BNL-91286-2009-IR 

Evaluation of Gas, Oil and Wood Pellet Fueled 

Residential Heating System Emissions 

Characteristics 

Roger J. McDonald

December 2009 

Energy Sciences and Technology Department/Energy Resources Division 

Brookhaven National Laboratory

P.O. Box 5000 

Upton, NY 11973-5000 

www.bnl.gov 

Notice: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under 

Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The publisher by accepting the

manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up,

irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others 

to do so, for United States Government purposes. 
DISCLAIMER 

This report was prepared as an account of work sponsored by an agency of the

United States Government. Neither the United States Government nor any 

agency thereof, nor any of their employees, nor any of their contractors,

subcontractors, or their employees, makes any warranty, express or implied, or 

assumes any legal liability or responsibility for the accuracy, completeness, or any

third party’s use or the results of such use of any information, apparatus, product,

or process disclosed, or represents that its use would not infringe privately owned 

rights. Reference herein to any specific commercial product, process, or service 

by trade name, trademark, manufacturer, or otherwise, does not necessarily 

constitute or imply its endorsement, recommendation, or favoring by the United 

States Government or any agency thereof or its contractors or subcontractors. 

The views and opinions of authors expressed herein do not necessarily state or 

reflect those of the United States Government or any agency thereof. 
Evaluation of Gas, Oil and Wood Pellet Fueled Residential Heating System 

Emissions Characteristics 

Brookhaven National Laboratory 

Energy Sciences and Technology Department 

Energy Resources Division 

December 2009 

Roger J. McDonald 

Under Agreement No. 8909 

New York State Energy Research and Development Authority 

Managed by 

Brookhaven Science Associates, LLC 

For the United States Department of Energy under 

Contract No. DE-AC02-98CH10866
Legal Notes 

NYSERDA 

This report was prepared by Brookhaven National Laboratory in the course of performing

work contracted for and sponsored by the New York State Energy Research and 

Development Authority (NYSERDA). The opinions expressed in this report do not 

necessarily reflect those of NYSERDA or the State of New York, and reference to any 

specific product, service, or method does not constitute an implied or expressed 

recommendation or endorsement of it. Further, NYSERDA and the State of New York 

make no warranties or representations, expressed or implied, as to the fitness for 

particular purpose or merchantability of any product, apparatus, or service, or the 

usefulness, completeness or accuracy of any process, methods, or other information 

contained, described, disclosed, or referred to in this report. NYSERDA, the State of New 

York, and the contractor make no representations that the use of any product, apparatus,

process, method, or other information will not infringe privately owned rights and will 

assume no liability for any loss, injury, or damage resulting from, or occurring in

connection with, the use of information contained, described, disclosed, or referred to in 

this report. 

United States Department of Energy 

This report was prepared as an account of work sponsored by an agency of the United 

States Government. Neither the United States Government nor any agency thereof, nor 

any of their employees, nor any of their contractors, subcontractors, or their employees 

makes any warranty, express or implied, or assumes any legal liability or responsibility 

for the accuracy, completeness, or usefulness of any information, apparatus, product, or 

process disclosed, or represents that its use would not infringe privately owned rights. 

Reference herein to any specific commercial product, process, or service by trade name, 

trademark, manufacturer, or otherwise, does not necessarily constitute or imply its 

endorsement, recommendation, or favoring by the United States Government or any 

agency, contractor or subcontractor thereof. The views and opinions of authors expressed

herein do not necessarily state or reflect those of the United States Government or any 

agency, contractor, or subcontractor thereof. 

Acknowledgements 

The author would like to acknowledge the valuable contributions of many people who 

have either worked on parts of this project or provided valuable critique of the many

drafts of this report including C.R. Krishna, PH.D., Thomas A. Butcher, Ph.D., Yusuf 

Celebi, George Wei, Wei Lin Litzke all from Brookhaven National Laboratory, and John

E. Batey of Energy Research Center Inc. and of course the project managers at 

NYSERDA which included Raymond Albrecht (retired), Nathan Russell and Peter 

Douglas. 

ii
Table of Contents 

Legal Notes......................................................................................................................... ii

Acknowledgements ............................................................................................................ii

Executive Summary.......................................................................................................... vii 

I. Introduction ..................................................................................................................... 1 

A. Overview.................................................................................................................... 1 

B. Report Organization ................................................................................................... 2 

II. Background .................................................................................................................... 3 

A. Fuel Use Demographics and Current Fuel Specifications......................................... 3 

B. Fuel Characteristics.................................................................................................... 3 

C. Prior Research in Emissions from Residential Heating Systems............................... 4 

D. Fine Particulate Emissions and Related Air Quality Concerns.................................. 5 

E. Considerations Related to Pending Changes in Diesel Fuel Specifications............... 7 

F. MANE-VU ................................................................................................................. 7 

G. Importance of Sulfur Content in Petroleum Heating Fuels........................................ 8 

H. Middle Distillate Fuel Cost and Product Supply Concerns ....................................... 9 

III. Test Plan...................................................................................................................... 11 

A. List of Equipment Included in the Project .............................................................. 11 

B. Test Plan................................................................................................................... 11 

IV. Measurement Technique............................................................................................. 13

V. Results ..........................................................................................................................17 

A. Oil-fired cast iron boiler and flame retention head burner, firing various fuels...... 17 

B. Oil-fired warm air furnace, with flame retention head burner and various fuels..... 25 

C. Gas-fired cast iron boiler, atmospheric burner and electronic spark ignition .......... 28 

D. Gas-fired warm air furnace, in-shot induced draft burner with spark ignition ........ 30 

E. Gas-fired condensing aluminum boiler, premixed power burner, spark ignition..... 32 

F. Oil-fired condensing steel boiler, flame retention head burner, with various fuels . 33 

G. Oil-fired condensing furnace with flame retention head burner, various fuels ....... 38 

H. Oil-fired cast iron boiler with combustion gas recirculation burner (blue flame) ... 40 

I. Wood pellet stove; drop down over fed, open burner grate, and electric ignition .... 42 

J. Pellet stove, over fed burner, enclosed self-clean burn grate, electric ignition......... 44 

K. Wood pellet stove, horizontal under feed, open grate, with manual gel ignition .... 46 

VI. Conclusions................................................................................................................. 49 

A. Results for Oil-fired Heating Appliances................................................................. 49 

B. Discussion of Biodiesel Blends................................................................................ 51 

C. Results for Gas-fired Heating Appliances................................................................ 52 

D. Results for Wood Pellet Stoves Manufactured in the United States........................ 53 

E. Comparison of Results for all Residential Heating Appliances............................... 54 

VII. Recommendations..................................................................................................... 55 

Appendix A: Examples of Fuel Analysis Results............................................................. 57 

Appendix B: List of Abbreviations and Symbols .............................................................58

iii
List of Figures 

Figure 1. Schematic of the PM 2.5 Measurement............................................................. 15 

Figure 2. Cast iron boiler and PM 2.5 Dilution Tunnel Sampler...................................... 19 

Figure 3. BNL and EPA Staff Conducting Simulations PM 2.5 Measurements.............. 21 

Figure 4. Cast iron boiler fueled with ULS diesel fuel..................................................... 23 

Figure 5. Atmospheric gas-fired hydronic boiler.............................................................. 28 

Figure 6. Gas-fired warm air furnace with in-shot induced draft burner.......................... 31 

Figure 7. Gas-fired condensing boiler .............................................................................. 32 

Figure 8. Oil-fired condensing steel boiler during PM 2.5 dilution tunnel testing........... 34 

Figure 9. Cast iron boiler fired with biodiesel for comparison purposes.......................... 37 

Figure 10. Oil-fired condensing warm air furnace, 95% AFUE rating ............................ 38 

Figure 11. Combustion gas recirculation (blue flame) burner.......................................... 41 

Figure 12. Pellet stove with drop down over fed, open burner grate, electric ignition..... 42 

Figure 13. Stove, overfed burner, enclosed self-clean burn pot/grate, electric ignition... 44 

Figure 14. Pellet stove, side feed burner, open burner grate, and manual gel ignition..... 46 

Figure 15. Cast iron boiler, PM 2.5 as a function of sulfur content.................................. 50 

Figure 16. Cast iron boiler PM 2.5 mg/MJ, mg/kg, mg/dscm for three fuels................... 50 

Figure 17. PM 2.5 for conventional and condensing, boilers and furnaces...................... 51 

Figure 18. PM 2.5 emission factors for gas furnace, boiler and condensing boiler.......... 52 

Figure 19. Three stoves evaluated for PM 2.5 and PM > 2.5 Microns............................. 53 

Figure 20. Comparison of average PM 2.5 emissions for five heating fuel options......... 54 

iv
List of Tables 

Table 1. PM 2.5, oil-fired cast iron boiler, retention head burner, steady-state firing No. 2 ..... 19 

Table 2. PM 2.5, oil-fired cast iron boiler, retention head burner, cyclic operation, (EPA) ..... 20 

Table 3. Flue gases, oil-cast iron boiler, flame retention burner firing No. 2 fuel .................... 20 

Table 4. PM 2.5, oil-fired cast iron boiler with flame retention head burner firing LS fuel ..... 21 

Table 5. Flue gases, oil-fired cast iron boiler with flame retention head burner LS fuel .......... 22 

Table 6. PM 2.5, oil-fired cast iron boiler with flame retention head burner firing ULS........... 22 

Table 7. Flue gases, oil-fired cast iron boiler with flame retention head burner firing ULS ..... 23 

Table 8. PM 2.5, oil-fired cast iron boiler, flame retention head burner steady state, No. 2 ..... 24 

Table 9. Flue gases, oil-fired cast iron boiler with flame retention head burner, No. 2 ............ 24 

Table 10. PM 2.5, oil-fired cast iron boiler, retention head burner, No. 2, cyclic operation ..... 24 

Table 11. PM 2.5, oil-fired warm air furnace, retention head burner, No. 2 fuel ...................... 25 

Table 12. Flue gases, oil-fired warm air furnace, retention head burner, No. 2 fuel ................. 25 

Table 13. PM 2.5, oil-fired warm air furnace, retention head burner, LS fuel .......................... 26 

Table 14. Flue gases, oil-fired warm air furnace, retention head burner, LS fuel ..................... 26 

Table 15. PM 2.5, oil-fired warm air furnace, retention head burner, ULS fuel ....................... 27 

Table 16. Flue gases, oil-fired warm air furnace, retention head burner, ULS fuel .................. 27 

Table 17. PM 2.5, gas-fired cast iron boiler, atmospheric burner, steady state operation ......... 28 

Table 18. Flue gases, gas-fired cast iron boiler, atmospheric burner, steady state operation..... 29 

Table 19. PM 2.5, gas-fired cast iron boiler, atmospheric burner, cyclic operation .................. 29 

Table 20. PM 2.5, gas-fired furnace, induced draft burners, steady state operation................... 30 

Table 21. Flue gases, gas-fired furnace, induced draft burners, steady state operation ............. 30 

Table 22. PM 2.5, gas-fired furnace, induced draft burners, cyclic operation ........................... 31 

Table 23. PM 2.5, gas-fired condensing aluminum boiler, premixed power burner ................. 32 

Table 24. Flue gases, gas-fired condensing aluminum boiler, premixed power burner ............ 33 

Table 25. Flue gases, oil-fired condensing steel boiler, flame retention burner, No. 2 fuel ...... 33 

Table 26. PM 2.5, oil-fired condensing steel boiler, flame retention burner, No. 2 fuel ........... 34 

Table 27. PM 2.5, oil-fired condensing steel boiler, flame retention burner, ULS fuel ............ 35 

Table 28. Flue gases, oil-fired condensing steel boiler, flame retention burner, ULS fuel ....... 35 

Table 29. PM 2.5, oil-fired condensing steel boiler, flame retention burner, biodiesel ............ 36 

Table 30. Flue gases, oil-fired condensing steel boiler, flame retention burner, biodiesel ....... 36 

Table 31. PM 2.5, oil-fired cast iron boiler, flame retention head burner, biodiesel fuel .......... 37 

Table 32. Flue gases, oil-fired cast iron boiler, flame retention head burner, biodiesel fuel...... 37 

Table 33. PM 2.5, oil-fired condensing warm air furnace, retention head burner, No. 2 .......... 38 

Table 34. Flue gases, oil-fired condensing warm air furnace, retention head burner, No. 2 ..... 39 

Table 35. PM 2.5, oil-fired condensing warm air furnace, retention head burner, LS fuel ....... 39 

Table 36. Flue gases, oil-fired condensing warm air furnace, retention head burner, LS ......... 39 

Table 37. PM 2.5, oil-fired condensing warm air furnace, retention head burner, ULS ........... 40 

Table 38. PM 2.5, oil-fired condensing warm air furnace, retention head burner, ULS ........... 40 

Table 39. Flue gases, cast iron boiler with combustion gas recirculation burner, ULS ........... 41 

Table 40. PM 2.5, cast iron boiler with combustion gas recirculation burner, ULS ................. 41 

Table 41. PM 2.5, wood pellet stove, drop down over fed, open burner grate .......................... 43 

Table 42. Flue gases, wood pellet stove, drop down over fed, open burner grate ..................... 43 

Table 43. PM 2.5, pellet stove, over fed burner, closed self-clean burn grate ........................... 45 

Table 44. Flue gases, pellet stove, over fed burner, closed self-clean burn grate ...................... 45 

v
Table 45. PM 2.5, wood pellet stove, horizontal under feed burner, open grate ....................... 47 

Table 46. Flue gases, wood pellet stove, horizontal under feed burner, open grate .................. 48 

vi
Executive Summary 

This study has measured the emissions from a wide range of heating equipment burning

different fuels including several liquid fuel options, utility supplied natural gas and wood 

pellet resources. The major effort was placed on generating a database for the mass 

emission rate of fine particulates (PM 2.5) for the various fuel types studied. The fine 

particulates or PM 2.5 (less than 2.5 microns in size) were measured using a dilution

tunnel technique following the method described in US EPA CTM-039. The PM 2.5

emission results are expressed in several units for the benefit of scientists, engineers and 

administrators. The measurements of gaseous emissions of O2, CO2, CO, NOx and SO2

were made using a combustion analyzer based on electrochemical cells These 

measurements are presented for each of the residential heating systems tested. This 

analyzer also provides a steady state efficiency based on stack gas and temperature 

measurements and these values are included in the report. The gaseous results are within

the ranges expected from prior emission studies with the enhancement of expanding these 

measurements to fuels not available to earlier researchers. Based on measured excess air 

levels and ultimate analysis of the fuel’s chemical composition the gaseous emission

results are as expected and fall within the range provided for emission factors contained 

in the US-EPA AP 42, Emission Factors Volume I, Fifth Edition. Since there were no 

unexpected findings in these gaseous measurements, the bulk of the report is centered on 

the emissions of fine particulates, or PM 2.5. 

The fine particulate (PM 2.5) results for the liquid fuel fired heating systems indicate a 

very strong linear relationship between the fine particulate emissions and the sulfur 

content of the liquid fuels being studied. This is illustrated by the plot contained in the 

first figure on the next page which clearly illustrates the linear relationship between the

measured mass of fine particulate per unit of energy, expressed as milligrams per MegaJoule (mg/MJ) versus the different sulfur contents of four different heating fuels. These 

were tested in a conventional cast iron boiler equipped with a flame retention head 

burner. The fuels included a typical ASTM No. 2 fuel oil with sulfur below 0.5 percent 

(1520 average ppm S), an ASTM No. 2 fuel oil with very high sulfur content (5780 ppm 

S), low sulfur heating oil (322 ppm S) and an ultra low sulfur diesel fuel (11 ppm S). 

Three additional oil-fired heating system types were also tested with normal heating fuel, 

low sulfur and ultralow sulfur fuel. They included an oil-fired warm air furnace of

conventional design, a high efficiency condensing warm air furnace, a condensing 

hydronic boiler and the conventional hydronic boiler as discussed above. The linearity in 

the results was observed with all of the different oil-fired equipment types (as shown in 

the second figure on the next page). A linear regression of the data resulted in an Rsquared value of 0.99 indicating that a very good linear relationship exits. This means 

that as sulfur decreases the PM 2.5 emissions are reduced in a linear manner within the 

sulfur content range tested. At the ultra low sulfur level (15 ppm S) the amount of PM 2.5 

had been reduced dramatically to an average of 0.043 mg/MJ. 

vii
Cast Iron Boiler, Flame Retention Head Burner

With Four Distillate Fuels, Sulfur Range 11-5780 ppm

y = 0.0355x

R2

 = 0.9969

0

50

100

150

200

250

0 1000 2000 3000 4000 5000 6000 7000

Sulfur ppm

PM mg/kg

Cast iron boiler, PM 2.5 as a function of sulfur content 

Conventional and Condensing Oil Fired Heating Appliances

With Middle Distillate Fuels, Sulfur Range 11-1520 ppm 

y = 0.0009x

R2

 = 0.9892

y = 0.0014x

R2

 = 0.9907

y = 0.0013x

R2

 = 0.9999

y = 0.0013x

R2

 = 0.9961

0

0.5

1

1.5

2

2.5

3

0 500 1000 1500 2000 2500

Sulfur ppm

PM 2.5 mg/MJ

Boiler

Furnace

Cond. Boiler

Cond. Furnace

Linear (Boiler)

Linear (Furnace)

Linear (Cond. Boiler)

Linear (Cond. Furnace)

viii

PM 2.5 for conventional and condensing, boilers and furnaces
hree different gas-fired heating systems were tested. These included a conventional inhree wood pellet stoves were included in this study. Wood pellet properties vary greatly 

iscussion:

 currently have many choices to heat their homes. These choices include 

o summarize, natural gas has low PM 2.5 emissions but moderate carbon dioxide 

Transitioning the sulfur content of fuel oil to ultra low levels (less than 15 ppm) results in 

T

shot induced draft warm air furnace, an atmospheric fired hydronic boiler and a high

efficiency hydronic boiler. The particulate (PM 2.5) measured ranged from 0.011 to 

0.036 mg/MJ (as shown in the first figure on the next page). 

T

depending on the raw material source used in their manufacture. All three stoves tested 

were fueled with premium (low ash) wood pellets obtained in a single batch to provide 

for uniformity in the test fuel. Unlike the oil and gas fired systems, the wood pellet stoves

had measurable amounts of particulates sized above the 2.5-micron size that defines fine 

particulates (less than 2.5 microns). The fine particulate emissions rates ranged from 22 

to 30 mg/ MJ with an average value of 25 mg/MJ for the three stoves tested (as shown in

the second figure on the next page). 

D

Homeowners

burning natural gas, heating oil, wood. Natural gas use results in very low levels of PM

2.5 emissions but being a hydrocarbon fuel it emits substantial levels of carbon dioxide. 

ASTM No. 2 fuel oil fired heating appliances produce PM 2.5 levels that are about 130 

times higher than natural gas and higher emission levels of carbon dioxide. Wood pelletfired heating appliances made in the Untied States produce PM 2.5 levels that are

approximately 15 times higher than ASTM No. 2 fuel oil and from about 590 to 1850 

times the levels possible with either utility gas or ultra low sulfur oil fueled appliances. 

Wood pellet heating fuel is often selected over other forms of wood fuel choices based on 

EPA and DOE guidance. This guidance suggests that the use of wood pellet appliances is 

a good choice because they are considered to be the lowest emitters of particulates when 

compared to other type of wood burning appliances. Wood pellet fuel is a renewable 

resource that absorbs carbon dioxide during the natural growth cycle. This is considered

to be a benefit in helping to mitigate global climate changes by effectively reducing the 

carbon dioxide emissions that otherwise would be attributed to the use of wood pellet 

fuel. Like wood, biodiesel is also a renewable fuel and also absorbs carbon dioxide in the 

growth cycle of the crop plants used to produce the raw materials for biodiesel

production, for example soybean or other seed crops. Biodiesel can be blended with 

ASTM heating No. 2 or ultra low sulfur heating oil. In either case it would effectively 

reduce the emissions of carbon dioxide based on its renewable nature. The extent of the

carbon dioxide reduction would be proportional to the amounts of biodiesel used in the 

blends. 

T

emissions. Wood pellet fuel has much higher PM 2.5 emission levels (based on current 

technology) but effectively lower carbon dioxide emissions due the renewable nature of 

trees that absorb carbon dioxide as they grow. ASTM No. 2 fuel as currently used has 

higher emissions of PM 2.5 than natural gas, much lower PM 2.5 emissions than wood 

pellet fuel and higher levels of carbon dioxide emissions than both alternatives.

ix
PM 2.5 emission factors for gas furnace, boiler and condensing boiler

Three stoves evaluated for PM 2.5 and PM > 2.5 Microns

PM 2.5 Emission Factors for Several Natural Gas Fired Appliance

2

0.011

0.63

0.043 0.016

0.9

0.06 0.036

0.13

1.96

0

0.5

1

1.5

mg/MJ mg/kg Concentration at 3% O2

Furnace Boiler Condensing Boiler

0

100

200

300

400

500

600

mg/MJ mg/kg mg/dscm@ 3% O2 mg/MJ mg/kg mg/dscm@ 3% O2

Stove I Stove J Stove K

PM Less than 2.5 Microns (PM 2.5) PM Greater than 2.5 Microns

x
PM 2.5 emissions are on the same order of magnitude as natural gas (see figure below) 

its higher levels of carbon dioxide. Natural gas produces about 30 percent less

arbon dioxide per Btu when compared to ASTM No. 2 or ultra low sulfur heating oil. 

lending of ultra low sulfur with biodiesel in the future is anticipated as a alternative fuel 

hoice and the resulting fuel blend would have very low PM 2.5 emissions as well as low 

et carbon dioxide emissions when the renewable nature of the fuel is taken into 

accounted. This report presents carbon dioxide data as it was measured but the analysis of 

e net carbon dioxide reduction based on the use of renewable fuels is beyond the scope 

f the current project 

he question of how to reduce PM 2.5 emissions in areas that currently do not meet the 

ia for EPA attainment is complex and is not part of the scope of this project. This 

roject does however provide important data that should be useful to the overall decisionaking process with regard to residential heating technology in New York State as well 

s the other New England and Mid-Atlantic States where a majority of home heating is 

ased on fuel combustion technologies.

Comparison of average PM 2.5 emissions for five heating fuel options

but still em

c

B

c

n

th

o

T

criter

p

m

a

b

Comparison of Average PM2.5 for Five Heating Fuel Types

for Hydronic Boilers and Warm Air Funaces

0.016 0.025 0.49

1.32

0.011 0.06 0.51

2.1

25

0

5

10

15

20

25

30

Gas ULS LS ASTM No. 2 Wood Pellet

PM 2.5 mg/MJ

Boiler Furnace

Note: Wood pellet stoves included

xi
Evaluation of Gas, Oil and Wood Pellet Fueled Residential Heating System 

Emissions Characteristics 

I. Introduction 

A. Overview

This project provides an up-to-date evaluation of emissions from residential gas; oil and 

wood pellet fired heating equipment. This report contains an introduction to the topic and 

iscusses recent trends that impact the subject matter. Then the project plan is reviewed 

different ways including factors based on

concentration, weight and energy content. 

The project has developed emissions profiles for various equipment designs. These

include units considered to be of conventional design as well as more modern designs. 

Modern designs can be characterized by low emission factors (for example lower

nitrogen oxides) and or high thermal efficiency. High efficiency generally correlates with 

the inclusion of a condensing heat exchanger that captures latent heat and thereby reduces 

the energy discarded with the exhaust gases. This latent energy is typically lost as steam 

vapor contained in the stack gases. Different furnace and boiler units that incorporated

condensing technology were evaluated. These units are designed specifically for use with 

natural gas or heating oil. Efficiency levels range up to the 90-95% level for condensing 

models. Units designed for heating oil fuel were tested using normal ASTM No. 2 fuel 

oil, low sulfur fuel with sulfur content below 500 ppm, ultra low sulfur fuel with sulfur 

below 15 ppm and biodiesel fuel, also considered as an ultra low sulfur content fuel. The 

gas-fired units were tested using gas delivered via pipeline from the local utility on Long 

Island. During the course of the project the project sponsor (NYSERDA) funded an 

additional task to include measuring the emissions from wood pellet stoves. Three 

different wood pellet stoves were tested. These were all of currently marketed designs 

incorporating sidewall venting, variable fuel feed rates and forced room air circulation. 

The wood pellet units were fired with a premium wood pellet fuel, less than 1% ash

content, primarily intended for residential use. While the larger portion of the particulate

emissions of the three wood pellet stoves were categorized as fine particulates (PM 2.5) 

these units did have measurable amount of particulates sized over 2.5 microns in 

diameter. 

The pro ity and

commitment by NYSERDA. Phase one of the project sought to measure emissions from a 

representative sample of typical utility gas and oil-fired, residential heating systems as 

found in homes and small businesses in New York State. Oil-fired heating systems were 

tested with conventional heating oil (0.2% or 2,000 ppm sulfur), low sulfur diesel fuel

d

and the measurement techniques are discussed. The results of all testing are presented

including data on the traditional gaseous stack emissions including carbon monoxide,

calculated carbon dioxide based on oxygen concentration, nitrogen oxides and oxides of

sulfur. Emissions are also reported for fine particulates (PM 2.5) and those of larger size 

(larger than 2.5 microns) using a dilution tunnel sampling method. These particulate 

emissions are presented in various

ject was originally structured in two phases based on funding availabil

1
(500 ppm sulfur), and ultra-low sulfur diesel fuel (15 ppm sulfur). During phase o

was a great deal of emergin

ne there

g interest in renewable forest based fuels and before phase 

ne was completed a modification to the project added an additional task to investigate 

m wood pellet stoves. These were currently marketed as a primary heat

source for use in smaller open format homes and also a supplemental heat source for

ting in general. Phase two of the project sought to measure emissions from

ore advanced heating technologies including low NOx burners and condensing heating 

n oil heating technology was somewhat more 

xpansive due to the nature of the fuel and the perceived possibilities for improvement

o

the emissions fro

residential hea

m

appliances (boilers and furnaces). Phase two also included the testing of both

conventional and advanced, oil-fired, heating technologies with liquid biofuels

(biodiesel). 

The largest portion of the effort was expended in generating the fine particulate data set

for the various equipment types mentioned above. Originally the project was based on 

evaluating emissions from gas and oil fired heating systems. Given existing EPA

emission factors for gas, oil and wood combustion there was the expectation that 

emissions would be lowest for gas, slightly higher for oil and higher yet for wood

combustion. The amount of effort placed o

e

based on changing fuel characteristics and equipment designs. 

B. Report Organization 

The main report is structured into six sections including an introduction, a discussion of 

background material primarily related to the topic of oil and gas fired equipment, a

review of the test plan as followed, a description of the measurement techniques applied,

a presentation of the project results, a summary of findings and finally recommendations 

based upon the study. 

2
II. Background 

A. Fuel Use Demographics and Current Fuel Specifications 

Utility gas and heating oil are widely used sources of energy providing safe, economical 

and efficient space heating comfort in approximately 100 million homes in the United 

States. In New York State (NYS) the majority of homes are heated with these fuels. Gas 

is used in 3,292,188 housing units and this represents 47% of homes in NYS. The largest 

concentration of oilheat use in the nation is found in NYS with 2,336,714 housing units 

identified as using oil as the main heating fuel (33% of all homes in NYS). 1

 The United 

tates Department of Energy’s Energy Information Agency (DOE/EIA) research on

eir main heating fuel. The 

se of wood pellets to heat living spaces is a growing industry but still it represents a very

ng homes, less than one percent of homes in the USA. Pellet 

toves and pellet fuel use started in the Pacific Northwest. The popularity of the stoves

states with the highest annual sales. The East is now the number 

one market in the USA. The North Central and Rocky Mountains are number two, the 

Pacific Northwest is number three and the Southeast is number four. 4

In NYS approximately 600,000 homes use wood in some form for primary or 

supplemental space heating. 1

 There is no apparent statistical information on the number 

of homes currently using wood pellets in NYS. The use of wood pellets is fairly popular 

in the Northeast and New England states. It is expected that a significant percentage of 

the national population of wood pellet units are likely located in NYS. With traditional 

heating fuel energy prices recently increasing dramatically, there has been a growth spurt 

in pellet-fueled unit sales. This is also coupled with a growing environmental interest in 

wood sourced fuels as a renewable fuel option in some homeowner’s opinions. 

 

B. Fuel Characteristics 

The American Society of Testing and Materials (ASTM) maintain nationally recognized 

standards for specifications defining liquid fuels when used in the United States. These 

include those for No. 1 (kerosene) and No. 2 (heating oil) fuel oils that are used in most 

small residential and commercial sized fuel oil burning equipment. In addition to 

specifying physical properties such as density, viscosity and heating value the ASTM 

S

housing characteristics indicates that the average gas heated home uses 112,300 cubic 

feet of gas and average oil heated home consumes 873 gallons of fuel each year. 2

Applying these average uses to NYS produces an estimated fuel use of 369.7 billion 

cubic feet of utility gas and over 2.04 billion gallons of oil each year. 

According to the Pellet Fuel Institute (PFI), wood pellets as a residential heating fuel are 

currently consumed in approximately 800,000 homes nation wide. 3

 A great deal of these 

homes use wood pellets as a supplemental heating source not th

u

small fraction of all existi

s

was such that the second initial market was in the Northeast. Initially the fuel was 

transported from the west to the east coast. As the number of stoves increased in the east,

local production of pellet fuel began in the east. Then the market expanded to most other 

parts of the country. During the last five years there has been strong growth in the 

Northeast and Eastern

3
specifies the maximum sulfur content of the fuels. Sulfur content directly impacts

missions of sulfur oxides and particulates. The vast bulk of this middle distillate heating 

he ASTM specifications

egarding sulfur limits for both No. 1 and No. 2 fuels state that they must contain no more 

els were generally

ungible and were considered the same product stored in the same tank at fuel terminals.

on the ash content

f the fuel. Premium pellets used largely for residential equipment are specified as having

or Research in Emissions from Residential Heating Systems 

umerous emission studies have been conducted on oil, gas and wood pellet combustion 

e

fuel is No. 2 or more commonly referred to as heating oil. T

r

than 0.5% (5,000 ppm) sulfur by weight. Based upon a yearly survey of US oil refineries 

the typical sulfur level for No. 2 heating fuel over the last decade has been approximately 

2,000 ppm. This is well below the limit established in the ASTM specification. There are 

also two relatively new specifications, added in June of 2002, that define new low sulfur

fuel types, No. 1 Low Sulfur and No. 2 Low Sulfur, which contain no more than 0.05% 

or 500 ppm sulfur by weight. In addition diesel fuel is also a middle distillate fuel and can 

be considered as an acceptable heating oil fuel, if not for regulations segregating it by 

sulfur content and color (diesel is un-dyed) for taxation purposes. Diesel also has certain

specifications that fuel oil does not currently need to meet, sulfur content below 15 ppm 

being one of the most relevant to the current project. Diesel meets fuel oil specification

but fuel oil does not meet the diesel specification. Early on, these fu

f

As emissions from the transportation sector became a major concern the two were

basically separated based on sulfur content. Diesel first had a limit of 500-ppm sulfur and 

more recently that was reduced to the current ultra low level of 15 ppm. 

Utility or “Natural” gas is primarily methane and can contain minor amounts of other 

combustible hydrocarbon based gases. There is a very small amount of sulfur in natural 

gas and a large portion of this is from the sulfur containing odorants, compounds added to 

the gas to enable leak detection by its users. The combined sulfur content of utility gas is 

not openly reported in non-propriety documents and varies depending on geographic 

location of the source and degree to which it is removed. It is on the order of 10-ppm by

weight based on the analysis of the gas delivered by the local utility on Long Island, NY. 

Wood pellets are classified as premium, standard or utility grade based

o

less than 1% ash. Standard grade pellets can have up to 2% ash by weight and utility 

grade less than 6% ash. The exact chemical composition and physical properties of fuel

pellets are based upon the raw material and vary from place to place depending on what 

types of tree the wood comes from. There are specifications for minimum density,

physical dimensions; maximum chloride content, which limits the potential for stove 

corrosion and ash, content that factor into the cleaning and maintenance frequency for the 

user. Generally the heating value averages 8,000 –9,000 Btu per pound (dry basis). 3, 4 

C. Pri

N

systems. Very few of these studies have attempted to measure fine particulate (PM 2.5) 

emissions using a dilution tunnel based methodology on small residential heating

appliances. Individually these residential emission sources are not large enough to be of 

concern, but as a disperse source they are considered to be a significant concern. The last 

comprehensive emissions study on residential oil heating equipment was conducted at 

4
Brookhaven National Laboratory (BNL) in 1990. It answered a lot of questions and some

of that data was important in documenting the advances of equipment design at that time. 

This reduction in emissions resulted from many years of design improvements since the 

first oil appliance emissions study conducted by Battelle Laboratory –Columbus, OH in

1970. While both studies included particulate emissions neither dealt specifically with 

measuring fine particulates (PM 2.5). 5, 6, 6 

Currently the most important area of concern is the emission of fine particulate (PM 2.5)

due to health concerns as well as their contribution to atmospheric haze. There is also 

concern over how to measure it accurately and the meaning of those measurements when 

compared to alternative techniques. When using fuel oil, the formation of sulfur oxides,

sulfates and sulfides are the area of largest concern. These are obviously linked to the 

sulfur content of the fuel. Likewise the particulate emissions from residential gas fired 

heating systems had not been a major area of concern based on the low emission factors 

traditionally associated with gas combustion. 

 

The potential for PM 2.5 reduction with heating oil had also been documented to some

extent by the CANMET Energy Technology Center in Canada in an experiment where 

the emission rate for a range of varying sulfur content fuels from 6,000 down to 500 ppm 

as determined in a single boiler system of the type used in single-family residential 

our and 1-hour standards. Standards are set to protect the health of the most sensitive 

.

ard to the current

mbient air quality concerning the Northeast. Sulfur dioxide (SO2) is in attainment; this

w

buildings. The results indicated a basically linear relationship between sulfur content and 

fine particulates measured as PM 2.5. 7

 

D. Fine Particulate Emissions and Related Air Quality Concerns 

The U.S. EPA regulates six air pollutants SO2, NOx, O2, CO, Pb and particulate. EPA 

has established National Ambient Air Quality Standards including annual, 24-hour, 8-

h

humans. EPA set up a monitoring network to measure ambient air quality. EPA also 

developed an inventory of emissions. 8

 

Initially EPA regulated total suspended particulate (TSP). Later PM 10, which are

particles smaller than 10 microns and recently PM 2.5, particulates less than 2.5 microns

in size were regulated. These fine particulates can be easily trapped in the lungs during 

normal respiration. The current standards for PM 2.5, described in micrograms per cubic 

meter of air (ug/m3) are 65 ug/m3 – 24-Hour and 15 ug/m3 – annual average. Areas 

where concentrations are below the standards are referred to as non-attainment areas 9

The results from local EPA monitoring stations are mixed with reg

a

can affect the issue of acid rain and secondary particulate formation in the upper

atmosphere. With regard to particulate emissions; PM 2.5 – 24 Hour –is also in

attainment, with PM 2.5 – Annual non attainment areas include DC, WV, DE PA, NJ, 

Bronx, NY City & New Haven, CT. 

5
States with non-attainment areas are being required to prepare State Implementation 

Plans (SIPs) so as to regain and/or maintain attainment for all regulated emissions. In the 

Northeast there has been considerable effort to deal with this problem on a regional basis

for several reasons. There is a great deal of concern that the different states would have

different regulations. An example would be, if the sulfur content limit imposed on fuel oil 

varies form state to state, this would increase cost for everyone. It would unduly

omplicate the bulk delivery, storage and dispensing of the fuel. Like-wise the legal 

e Eastern United States, sulfates are a very 

portant part of the total ambient particulates. There has been considerable debate over 

he regional PM 2.5 picture. A national plan to 

mit air quality concerns with mobile sources is well in place for vehicles that use diesel 

rom numerous 

ources including in part, the combustion of home heating oil. This is of particular

n sector. EPA had no PM 2.5 data for residential

eating systems in its emission inventory until very recently. 

nd

itrate formed in the atmosphere from gaseous emissions of sulfur dioxide (SO2) and

to have, if one were to try to interpret the inventory 

f directly emitted PM 2.5 without the benefit of modeling or chemically characterized 

air samples. Studies related to coal fired power plants have attributed 40 percent or more 

c

requirements for wood burning appliances might impose market limitations if one state 

does not match the next with regard to allowable appliance emission limits. 

There is general agreement that ambient fine particulates (PM 2.5) do have significant 

potential health impacts and these are currently being addressed with regard to air quality. 

These fine particulates include organic and elemental carbon formed from combustion 

sources, acid aerosols that are produced as combustion products cool and mix with 

ambient air, road dust, and other sources. In th

im

the past decade about what size particulates should be regulated and what consideration 

should be given to composition versus simply total mass in regulations. The total mass of 

particulates under 2.5 microns is now the focus. Environmental regulators are currently 

working to put in place programs to meet the EPA ambient air standards for PM 2.5. In 

the Northeast and Mid-Atlantic regions the combustion of distillate oil in stationary and 

mobile sources is a very important part of t

li

fuel as discussed earlier. Ambient PM 2.5 includes sulfates and is emitted f

s

interest in New York State where over 2,300,000 households use oilheat as the primary 

heating fuel. The EPA has reported the major types of PM 2.5 as being carbon, sulfates,

ammonia and nitrate in descending order based on data from regional monitoring

stations. The major sources according to EPA are from all types of oil combustion, large 

industrial processes and the transportatio

h

The issue of combustion related PM 2.5 is complex and it results from ground level 

primary emissions of PM 2.5 and also secondary PM 2.5 that results from atmospheric 

chemical reactions of gaseous pollutants. A significant portion of the PM 2.5 is likely 

generated from ground sources as it forms rather rapidly once the combustion products 

hit the ambient air. The principal types of secondary particles are ammonium sulfate a

n

oxides of nitrogen (NOx), reacting with ammonia (NH3). The main sources of SO2 are 

the combustion of fossil fuels in boilers and the main sources of NOx are combustion of 

fossil fuel in boilers and mobile sources. Secondary particles comprise approximately 

50% of PM 2.5 ambient concentrations throughout the East and many western urban 

areas. Thus, direct emissions have only about one half the impact on PM 2.5

concentrations that they would appear

o

6
of the PM 2.5 from this type of upper atmosphere reaction causing secondary PM 2.5. 

Primarily this is reported as a sulfate related problem although some research papers have

suggested that merely limiting sulfur in the fossil fuel may not resolve the PM 2.5 issue.

This is because in the absence of SO2, additional NOx in the atmosphere would likely

react with the ammonium in its place and just displace one form of PM 2.5 with another. 

One point to underline is that the PM 2.5 concern is not a simple problem to analyze and

another important point is that solving one potential pollutant pathway may create a new 

pathway to open up. 

E. Considerations Related to Pending Changes in Diesel Fuel Specifications 

) to 500 ppm. The plans

all for a phased transition through the year 2010 when all diesel fuel, on-road and offThere has been past interest on the part of the NYS legislature and the Department of 

Environmental Conservation concerning the possible beneficial impacts of further

reducing the sulfur content of heating fuel down to ultra-low levels (ULS) of less than 15 

ppm. This interest was and is associated with recent changes that have occurred in the 

other part of the light distillate fuel market. Diesel fuels (No.1 D and No. 2D) and heating

fuels (No. 1 and No. 2) are both considered middle distillates and in fact for many years 

were basically the same fuel with minor differences usually accommodated by the use of 

fuel performance additives in diesel fuel only when required. An example would be an 

additive to boost the cetane level to meet diesel specifications. The difference between a 

No. 1 and No. 2 fuel, be it with heating oil or diesel fuel, is in general defined by the 

viscosity limits. Earlier transportation sector programs had in several metropolitan cities

already demonstrated on a small scale the clean air benefits of using ULS (No. 1) diesel 

in localized applications. The most recent activity in the NYS legislature has been to 

propose legislation that will mandate the use of ULS as heating fuel in New York State’s 

non-attainment areas starting in 2011. 10 

The reason for this national shift to the new ultra-low sulfur fuel is related to improved 

air quality. In a national effort to enhance ambient air quality, the US EPA mandated that 

diesel fuels for highway vehicles shift to 15-ppm sulfur starting in 2006, followed in 

2007 by off road diesel fuel shifting from 5,000 ppm (maximum

c

road, must be Ultra Low Sulfur (ULS) with a maximum of 15-ppm sulfur by weight. The

shift towards the ULS fuel has allowed vehicle manufacturers to utilize catalytic

converter technologies for diesel engines to reduce tailpipe emissions. The use of these

catalytic converters was not possible with higher fuel sulfur concentrations because the 

sulfur would poison the catalytic materials rendering them useless. The use of ULS diesel 

allows for reductions in both NOx and fine particulates, PM 2.5. 

F. MANE-VU 

The Mid-Atlantic/Northeast Visibility Union (MANE-VU) has been formed to develop 

an approach to improve air in the region. This organization is reacting to the Federal 

Clean Air Act and Regional Haze rule that requires that the various states with nonattainment areas within their borders create State Implementation Plans (SIP s) to address 

reasonable progress in correcting the current level of air quality. In the primary regions 

7
where oilheat is the most popular, the individual states have joined this group to 

formulate a joint regional plan. This plan includes Best Available Retrofit Technology

(BART) for large source emitters; limiting sulfur in distillate and residual fuel oils used 

in the region and includes a 90% reduction in sulfur dioxide emissions from 167 electric 

generating unit stacks. This plan also calls for a continued evaluation of other control 

measures. The goal is to reduce the particulate levels in the air that contribute to the 

formation of haze and reduce visibility. There is a general consensus that most pollutants 

that affect visibility also contribute to unhealthy concentrations of fine particulates and 

zone. 11 

he states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island,

llate fuel oil. The latest plan being proposed 

ould call for limiting sulfur in heating oil in two stages. The first would be to transition 

o reduce air pollutants 

esulting form the transportation sector it has already been virtually eliminated from 

els. The most recent change is the 2006 shift to ultra-low sulfur content 

iesel at less than 15-ppm.

o

T

Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, the District of

Columbia along with the Penobscot Indian Nation and the St. Regis Mohawk Tribe 

comprise the voting members of MANE-VU. It was formed to encourage a coordinated 

approach to meeting the requirements of EPA's regional haze rules and reducing visibility 

impairment in major national parks and wilderness areas in the Northeast and MidAtlantic region. MANE-VU provides technical assessments and assistance to its

members, evaluates linkages to other regional air pollution issues, provides a forum for 

discussion, and encourages coordinated actions. MANE-VU also facilitates coordination 

with other regions. 

BNL has presented preliminary data from this project at various venues documenting

the changes in fine particulates (PM 2.5) as a function of the variation of sulfur content in 

different fuel oils tested. Representatives from MANE-VU have participated at these 

meetings. MANE-VU is currently having ongoing discussions with key stakeholders 

regarding limiting sulfur content in disti

w

to less than 500-ppm in New York, New Jersey, Pennsylvania and Delaware starting in 

2012 (this may possibly be delayed until 2014) with the other states following by 2014. 

The second stage would be to limit sulfur content to less than 15-ppm in New York, New 

Jersey, Pennsylvania and Delaware by 2016 and in the other states by 2018. 12

G. Importance of Sulfur Content in Petroleum Heating Fuels 

Sulfur is an element and in many instances an essential component of all living cells, it’s 

also an old traditional medicine and it’s also used in numerous commercial applications 

and industries. However, generally speaking sulfur is a problem for the petroleum

industry. It has been an issue for gasoline as well as diesel. T

r

transportation fu

d

When burned, sulfur forms several oxides, sulfur dioxide (SO2) being the predominant 

one, but also sulfites (SO3) and sulfates (SO4). None of these are good for the oilheat

industry. Sulfur dioxide in the flue products contributes to secondary fine particulate 

formation in the upper atmosphere by means of photochemistry driven by sunlight. Sulfur 

8
dioxide is also one of the air emissions that alternate heating fuels suppliers like to point 

out when making comparisons to their own product that generally have very low levels of

sulfur dioxide emissions. Sulfites and sulfates also contribute to the primary fine

particulate (PM 2.5) produced by oilheating systems accounting for the largest portion of 

the particulates measured. 

Sulfates form sulfuric acid aerosols that react with the iron in the metal walls of heat 

exchangers to form iron-sulfates. More than half of the fouling deposits removed from a

well tuned oil-fired heating system consists of iron sulfates and these non-carbon related 

eposits are the most difficult to remove due to their tenacity, binding with the metal 

s resulting from a cleaner heat exchanger are also associated with the

eduction in fouling deposits. 13

e potential 

eduction in sulfur oxide emissions by using low sulfur fuel oil in New York State is 

e potential reduction of

ulfur oxide emissions for the US is 140,000 tons a year. 

ices. As with most energy types these prices are unregulated

nd are determined by the laws of supply and demand. They represent a freely traded 

d

walls. 

A prior NYSERDA market demonstration project involving low sulfur fuel oil has 

proven the numerous benefits for the consumer and the oilheat marketer with absolutely 

no detrimental effects over a three-year trial of the low sulfur (500-ppm) fuel in over a 

thousand homes located in Albany, NY. The primary benefits of using distillate fuel oil

with reduced sulfur content are: an 80% reduction in sulfur oxide emissions and lower 

service costs for homeowners by reducing the rate of fouling deposits on heat exchange 

surfaces in boilers and furnaces. A small increase in system efficiency (1-2% per year) 

and fuel cost saving

r

The immediate benefit of using 500-ppm sulfur fuel in place of normal heating oil in 

New York State and the US would be a substantial decrease in sulfur oxide emissions by

reducing fuel sulfur from 0.20% to 0.05%. The emission rate per million Btu of fuel oil 

that is burned decreases from 0.20 to 0.05 pounds of SO2 based on research by BNL and 

the Energy Research Center Inc. (Easton, CT) using US EPA emissions factors. The 

benefit to New York can be estimated based on the US Census data from 2000 and 

average fuel consumption figures resulting in an estimated fuel oil use of 2.3 billion 

gallons a year. This is equivalent to 322 trillion Btu of oil a year at 140,000 Btu per 

gallon. By applying the emission rates for normal and low sulfur fuel oil, th

r

67,620,000 pounds or 33,800 tons of sulfur oxide per year. Th

s

H. Middle Distillate Fuel Cost and Product Supply Concerns

Fuel costs are an issue of concern as is the question of supply sources and logistics. This 

is an even more sensitive area of concern for heating fuels because during the winter 

heating season the supply pressures during periods of very cold temperatures can cause 

dramatic increases in fuel pr

a

commodity where the price can change from day to day or even hour to hour. When 

temperatures drop and demand increases many additional buyers enter the market. Many 

represent interruptible rate natural gas users that switch to an alternative fuel, heating oil,

as required under their contracts with the gas utilities that provide lower prices for gas in 

9
exchange for the ability to drop gas delivery to these customers during periods of high

demand. As a result more buyers enter the heating oil market and drive the prices up as 

the inventory drops. These extreme periods of cold weather can also cause fuel deliveries 

to the terminals more difficult or impossible due to harbors and rivers freezing over. 

At the 15-ppm sulfur level that EPA has mandated for diesel fuel starting in 2006 the cost 

f 900-gallons, which is very typical in NYS. As a point of reference the current 

ntaxed cost differential between low sulfur No. 2 (500-ppm S) fuel and standard heating

nergy’s Energy Information Agency (DOE/EIA-032(93) 

Pellet Fuel Institute (PFI), http://www.pelletheat.org/3/residential/index.html 

differential has been estimated to be as low as five cents based on EPA estimates or as

high as fifteen cents based on API estimates on a per gallon basis. If this were to be 

applied to heating fuels, this translates to a range of $45 to $135 per household per year 

to be able to go down to the 15-ppm sulfur level. This range assumes an annual fuel 

usage o

u

fuel oil (2000 ppm typical) has ranged from less than two to about four cents per gallon 

or less than $18 to $36 projected per year for the same typical NYS home. The actual 

reported cost differential for ULS diesel fuel during the first two years has ranged from

approximately 15 to 25 cents per gallon. 

References, Section II 

1 Patterns and Trends, New York State Energy Profiles: 1993-2007, New York State 

Energy Research and Development Authority, January 2009 

2 United States Department of E

3

4 Personal communication with Dan Henry, Vice President of Advanced Technology 

Hearth & Home Technologies and Member of PFI 

5 Emissions Characteristics of Modern Oil Heating Equipment, R. Krajewski, Y. Celebi,

R. Coughlan, T. Butcher and R.J. McDonald, Brookhaven National Laboratory, July 

1990, BNL-52249 

6 Investigation of Particulate Emissions from Residential Oil Fired Residential Heating 

Units, R. E. Barrett, D. W. Locklin and S. E. Miller (Battelle Columbus Laboratory) 

EPA-650/2-74-026, March 1974 

7 Assessing PM 2.5 Emissions from Distillate Fuel Oil Heating, S. Win Lee (CANMET 

Energy Technology Center-Ottawa), Paper No. 02-13, Proceedings of the 2002 National 

Oilheat Research Alliance Technology Symposium, BNL-52670, August 2002 

8 http://www.epa.gov/air/caa/peg/cleanup.html

9 http://www.epa.gov/air/particlepollution/

tal conservation law, in

lation to requiring a reduction in sulfur for all heating oil used in non-attainment areas,

10 Assembly Bill: A6896, Title: An act to amend the environmen

re

http://assembly.state.ny.us/

11 http://www.manevu.org/ Mid-Atlantic, Northeast Visibility Union 

12 MANE-VU Statement on Controls In MANE-VU June 20, 2007 

13 NYSERDA Low Sulfur Home Heating Oil Demonstration Project, John E. Batey and

Roger J. McDonald, BNL-7456-2005-IR, June 2005 

10
III. Test Plan 

Phase one of the project sought to measure emissions from a representative sample of

typical natural gas and oil-fired, residential heating systems as found in homes and small

usinesses in New York State. Oil-fired heating systems were tested with conventional 

(water).

cluded in the Project

d burner and various fuels 

nition 

power burner, spark ignition

boiler, equipped with blue flame retention head burner and fuel oil 

urner, open burner grate, manual gel ignition 

and adjusted for proper combustion air 

ign to vary the air-fuel ratio and or draft

ff to very slightly increased combustion air per adjustment

2

the combustion products, which was 

used to determine carbon dioxide levels by instrument calculation based on the fuel

chemical composition. Smoke levels were measured using ASTM Method D-2156 for

distillate fuels. Early evaluation tests using oil and gas fired systems were conducted and 

b

heating oil (at 0.2% or 2,000-ppm sulfur), low sulfur diesel fuel (at 500-ppm sulfur), and

ultra-low sulfur diesel fuel (at 15 ppm sulfur). During phase one there was a great deal of 

emerging interest in renewable forest based fuels and before phase one was completed a 

modification to the project added an additional task to investigate the emissions from 

wood pellet stoves that were currently being marketed as a supplemental heat source for 

residential heating. Phase two of the project sought to measure emissions from more 

advanced heating technologies including low NOx burners, gas and oil fired condensing 

boilers and furnaces. Phase two also included the testing of both conventional and 

advanced, oil-fired, heating technologies with liquid biofuels (biodiesel). One reason for

this was to see if a condensing heat exchanger could help eliminate emissions due to the 

scrubbing of emissions into the condensate

A. List of Equipment In

1. Oil-fired cast iron boiler, equipped with flame retention hea

2. Oil-fired warm air furnace, with flame retention head burner and various fuels 

3. Gas-fired sectional cast iron boiler, atmospheric burner and electronic spark ig

4. Gas-fired warm air furnace, in-shot induced draft burner and electronic spark ignition

5. Gas-fired condensing aluminum boiler, premixed

6. Oil-fired condensing steel boiler, with flame retention head burner, with various fuels 

7. Oil-fired condensing warm air furnace, flame retention head burner and various fuels 

8. Oil-fired cast iron

9. Wood pellet stove, over feed burner, open burner grate, electric ignition 

10. Wood pellet stove, over feed burner, closed self-cleaning burn grate, electric ignition 

11. Wood pellet stove, side feed b

B. Test Plan 

Each unit was evaluated for correct operation

within the limits of the equipment’s des

conditions. Gas supply pressures were checked to conform to the manufacturers

requirements. Oil-fired systems were adjusted to operate by first finding the trace smoke

point and then backing o

standards used by the oil heat industry. 

Measurements of combustion emissions were performed for each heating appliance

tested. These included gaseous emissions of nitrogen oxides (NOx), sulfur dioxide (SO ), 

carbon monoxide as well as oxygen concentration in

11
indicated only small differences between operation under steady state and cyclic 

conditions. Some of these early tests indicated a slightly higher level of particulates 

would be measured under steady state conditions in comparison to cyclic tests. In other 

cases this trend reversed. Under either operating test condition, cyclic or steady state, the 

results were very close. Testing under cyclic conditions was quite possible when the 

emission factor was high enough to allow for tests in a timely manner. This was not the 

case with the units with very low emission factors and this could have required many 

weeks for each test (meaning a single run) to accumulate a sufficient sample size to be 

weighted accurately. The project schedule would not allow for this. As a result and with 

the concurrence of the NYSERDA project manager all subsequent tests were run under 

steady state conditions. 

12
IV. Measurement Technique 

The basic flue gas emissions data was obtained using an elecronic analyzer with electrochemical cells capable of measuring oxygen, CO, NO, NO2 and SO2 as well as measuring 

stack gas temperature and determining steady state efficiency. The acceptance of portable 

electrochemical-based analyzers by state and federal environmental agencies has grown

significantly over the past decade. Numerous third party organizations have tested and 

evaluated the technology and found that not only does it satisfy the accuracy

requirements of many compliance-testing programs, but also it offers a more affordable 

and better time managed solution. Coupled with great cross utilization capability that can

identify improvements in the combustion, process and product quality, these analyzers

make a valuable asset to many types of combustion research. The specific analyzer used

in this project was a Testo Model 350 equipped with low range CO and NOx capabilities.

This specific device was evaluated, tested and its performance verified under the US 

EPA’s Environmental Technology Verification Program (ETV) by the Advanced

Monitoring Systems (AMS) Center, one of six technology areas under ETV and operated 

by Battelle (Columbus, OH) in cooperation with the EPA’s National Exposure 

Laboratory.

Fine particulate measurements were conducted by a series of tests to determine the 

gravimetric amounts of particulates below 2.5 microns (PM 2.5). This measurement 

technique is based on US EPA Conditional Tests Method (CTM) 39 for Measurements

of PM2.5 and PM10 Emissions by Dilution Tunnel Sampling (Constant Sampling Rate

Procedures). This method was developed for larger emissions sources like oil or gasfired power generation utilities or manufacturing plants. These units have stack

dimensions sized in several feet not a few inches as in our application. The method was

modified to accommodate the tighter geometry found with residential heating appliance 

vents. The primary modification included not using the particle sizing cyclones except for 

the wood pellet stove evaluations. These cyclones are normally used inside the stack and 

are intended to function at the stack temperature. A review of the literature on emissions 

from gas and middle distillate oil-fired appliances resulted in several references 

indicating that the particle sizes were well below 2.5 micron, and actually below 1 micron 

in size. This allowed us to review the situation with our project manager and the decision 

was to forgo the use of the cyclones for No. 2 heating oil fuel and gas-fired appliances.

This decision was not applicable to the investigation of wood pellet stoves. In this case a

single cyclone was employed that captured particles larger than 2.5 microns. Due to the 

extremely small diameter flues (4-inch) used with wood pellet stoves the procedure was 

again modified and the cyclone was installed outside the flue and equipped with a high

temperature heater tape and automatic controller to maintain the temperature at the same 

level as the internal stack temperature. 

At the test conditions established, a series of three measurements were made. The three 

samples were obtained at the same operating conditions and provided data evaluation 

based on the standard deviation for statistical reasons. If the standard deviation was quite 

high due to one measurement that test was repeated to see if more consistent data was

obtainable. 

13
Fuel oil samples were sent to reliable commercial testing laboratories for analysis of

as possible. When evaluating the wood pellet stoves the sample flue gas 

asses through a cyclone, with a cut-off sized for 2.5 microns, which is heated to and 

eighed using the analytical balance to determine

e amount of particulate material recovered. A similar technique using an acetone wash 

density, heating values and chemical constituents including hydrogen, carbon, sulfur,

nitrogen, ash and oxygen by weight. Likewise a sample of the wood pellets was sent to a

laboratory with a strong reputation for solid fuel analysis. In the case of the utility gas 

information regarding the analysis of the gas was supplied by the local gas utility. This 

information coupled with calculations for flue gas volumetric flows inclusive of excess 

air determinations allowed for calculations of the total volume of flue product at a given 

firing rate during each run. Test report examples are provided in the Appendix . 

The smoke measurement was obtained using a “Bacharach” smoke tester designed to

conform to ASTM D1256-94 (1999), Standard Test Method for Smoke Density in Flue 

Gases from Burning Distillate Fuels. The “Bacharach” smoke tester is a manually

operated smoke pump used to set up the air fuel ratio. 

The PM2.5 measurement system’s schematic is shown in Figure 1. The stack gas is

sampled through a nozzle of know dimensions located in the stack at conditions as close 

to isokinetic

p

controlled at the stack temperature. The probe and the sample flow meter venturi, which 

is used to measure the sample flow rate, are also kept heated. The sampled gas is cooled 

and diluted to near ambient conditions by mixing, at the mixing cone, with HEPA filtered

ambient cool dry air at about 65-700

 F as shown. The combined gas stream has sufficient 

time in the residence chamber for particulates to form and/or condense before they are

trapped by the 142-mm filter. A computer is used to control temperatures, to maintain

flow rates as particulate builds up on the filter and to collect the experimental data. The 

normal filter is desiccated and weighed to the nearest 1/10 milligram using an analytical

balance (Mettler Toeldo AG104) before and after sampling to determine the mass of PM

2.5 particulates collected. The stack conditions (oxygen concentration) and the sampling

flow rates can be used to relate this to stack concentration and hence to the fuel burning

rates. Two types of filters are used. The gravimetric samples are collected on borosilicate

glass microfiber filters with woven glass cloth bonded with PTFE (Teflon). This is done 

in triplicate for reasonable statistics. The protocol followed (CTM-39) for setting up and 

operating the sampling system is more complex than suggested in this outline of the 

procedure. The complete method can be downloaded from the US EPA’s website. 1

The compact size of the dilution tunnel sampler used in this project provides for the 

ability to wash down with acetone and subsequent particulate residue recovery. The

acetone rinse and residue is collected in pre-weighted aluminum tins. Then the acetone is

evaporated in a hood and the residue is w

th

was used to recover the sample from the sizing cyclone when used in the testing of the 

three wood pellet stoves. Several other research organizations have conducted dilution

tunnel sampling using very large apparatus that preclude an accurate recovery of this 

residue. 

14
Figure 1. Schematic of the PM 2.5 Measurement 

Concurrent with the beginning of this work, BNL hosted a research team from the US 

EPA tasked with conducting a detailed speciation profile of the fine particulates for a 

typical residential oil-fired boiler. This project involved testing a single unit with a single

sample of fuel and was conducted over a three-day period. The EPA team utilized a very 

large custom-built dilution tunnel sampler. This measurement system has been deployed

to conduct speciation profiles for various different types combustion systems generating 

fine particulate mater. This was done to determine if there are any unique emissions

ial vendor of emissions sampling equipment and was based on the EPA design 

eveloped for EPA CTM-039. This design was generated by another arm of the US EPA 

characteristics from these generic source types that could then be traced in their detailed

air quality monitoring stations located throughout the country. This would then enable 

them to apportion ambient particulate concentrations to be the result of these various 

generic sources. The EPA dilution tunnel involved a large truckload of equipment and

components. This emissions sampler was a modified dilution sampling system like that 

used by Hildemann et al. 2

After researching different possibilities BNL had acquired a very compact dilution 

sampler obtained under the US DOE cost share portion of this project. It was built by a 

commerc

d

15
tasked with instrumentation development for multiple users, who are interested in 

conducting fine particulate measurements for compliance to EPA regulations. 

 

The availability of both dilution tunnel samplers allowed BNL to conduct a direct 

simultaneous side-by-side comparison of the two measurement systems. While the EPA 

researchers were at BNL conducting their project BNL ran its measurement system in 

parallel sampling off the same stack at the same time. This provided BNL an opportunity 

to evaluate the performance of its compact dilution sampler against a larger version of a 

modified dilution sampling systems like that used by Hildemann et al.2

The boiler tested was a conventional cast iron boiler equipped with a flame retention head

burner. In this case, at EPA’s request the boiler was tested under cyclic on and off 

conditions according to the duty cycle specified in ASHRAE Standard 103-1193. The

unit was fired with conventional ASTM No. 2 heating oil with a sulfur content of 1,440 

ppm. The test was repeated three times over the course of three days. The gravimetric 

fine particulate emission factor measured by the EPA group was reported as 49 +/- 5 

mg/kg. The BNL measurement using the compact dilution sampler was 46 mg/kg with a 

standard deviation of 8 mg/kg. These can be compared to the existing emission factor 

listed in EPA AP-42, a value of 57 mg/kg. As will be discussed in this report the 

particulate levels measured are strongly impacted by the sulfur content of the fuel. 3

References, Section IV

1 http://www.epa.gov/ttn/emc/ctm.html

2 Hildemann, L. M.; Cass, G. R.; Markowski, G. R. A dilution stack sampler for 

collection of organic aerosol emissions: Design, characterization and field tests. Aerosol 

Sci. Technol. 1989, 10, 193-204, 1989. 

3 Physical and Ch ission, Micael D.

ays, Lee Beck, et ), 2496-2502 , 27 

emical Characterization of Residential Oil Boiler Em

H al., Environmental Science Technology, 2008, 42 (7

February 2008

16
V. Results 

List of Heating Equipment Included in the Emissions Characterization Project 

ith various fuels

. Oil-fired condensing warm air furnace, flame retention head burner and various fuels 

h the

aseous emissions measured. 

retention head burner, firing various fuels 

as a 5-section design with a nominal fuel input of 

States Department of Energy (DOE)) funding, see Figure 2. 

The use of this measurement system required the development of a consistent

methodology for its use based on the CTM-039 method. The technique requires careful

preparations in clean prep/recovery laboratory (chemical lab) before the test is conducted.

Then the sampling system is set up in the HVAC combustion-testing laboratory. The 

measurements are conducted and monitored to verify that conditions remain in 

approximately steady state and isokinetic conditions within reasonable ranges. Ancillary 

measurements like stack gas and flow measurements also need to be performed and

recorded. The length of system operation and sampling run time depends on the fuel type.

It can be anywhere from a day up to a week for the cleanest fuels. Then post-test sample 

filter conditioning and weighing is performed. The dilution tunnel is washed down for

residue recovery and a sample mass determination after acetone evaporation is performed

in the sample prep/recovery laboratory. The routine procedure now used was the result of

several months of mistakes and improvements. 

 

1. Oil-fired cast iron boiler, equipped with flame retention head burner and various fuels 

2. Oil-fired warm air furnace, with flame retention head burner and various fuels 

3. Gas-fired sectional cast iron boiler, atmospheric burner and electronic spark ignition 

4. Gas-fired warm air furnace, in-shot induced draft burner and electronic spark ignition

5. Gas-fired condensing aluminum boiler, premixed power burner, spark ignition 

6. Oil-fired condensing steel boiler, with flame retention head burner, w

7

8. Oil-fired cast iron boiler, equipped blue flame retention head burner fuel oil 

9. Wood pellet stove, over feed burner, open burner grate, electric ignition 

10. Wood pellet stove, over feed burner, closed self-cleaning burn grate, electric ignition 

11. Wood pellet stove, side feed burner, open burner grate, manual gel ignition 

The results are presented in tabular form for each unit tested. First the particulate data

will be presented and immediately after the gaseous emissions data will follow. The sole

exception is the first table where the gaseous emissions were poorly documented and are 

included in a note attached to the table for reference. All other data will follow the 

general format of first a table with particulate related data followed by a table wit

g

A. Oil-fired cast iron boiler and flame

The first unit tested was a sectional cast iron residential oil-fired boiler equipped with a 

flame retention head burner. This unit w

1.45 GPH with a DOE output of 175,000 Btu/hr and an AFUE rating of 85 %. This unit 

provided the opportunity to develop and refine the measurement techniques. In particular 

the dilution tunnel sampler was a new research tool purchased by BNL using United

17
During the testing of the first unit three different types of fuels were tested with varying 

ulfur content. These included nominal heating oil (ASTM No. 2) with various sulfur 

onoxide 

t

2), CO, 

h

out to be 

the ASTM

,000-ppm sulfur. Due to the two different fuel samples,

our test runs were conducted to see if any significant differences were observable. The 

rd

eviation) of 5 mg/kg for the four tests or in alternate units, 1.32 mg/MJ with STDEV of 

y, and volume flows. When 

resenting results for natural gas fired appliances and wood pellet stoves some of the

s

levels in the range of 1440 to 5870-ppm, low sulfur fuel at less than 500-ppm and ultralow-sulfur at less than 15 ppm sulfur. Gaseous emissions measurements under the

beginning of the project were limited to oxygen, stack temperature and carbon m

(CO) concentration while the PM 2.5 method was developed under the US DOE cos

shared portion of the work. Later as the routine was developed a more sophisticated

combustion analyzer was used (Testo 350) which recorded carbon dioxide (CO

nitrogen oxides (NOx), sulfur dioxide (SO2), oxygen as well stack temperature and

efficiency data. Due to early procedure development trials and errors the tests wit

regular (No. 2) fuel were run a second time. In this case the fuel used turned

much higher in sulfur content (5870-ppm). This was actually higher than

specification of less than 5000-ppm. This unit was tested under both cyclic and steady 

state conditions. 

Table 1 presents the data for the first test series for the oil-fired cast iron boiler, equipped

with a flame retention head burner using ASTM No 2 heating oil with nominal sulfur 

content under steady state conditions. The test laboratory’s main fuel tank holds 1,000 

gallon of NO. 2 heating fuel and a fuel delivery occurred in the middle of the tests. This 

resulted in two different fuel sulfur contents that were both in what is considered the 

nominal range, approximately 2

f

average particulate level measured was 60 mg/kg of fuel with a STDEV (standa

d

0.12 mg/MJ. The particulate levels are also expressed as pounds per million Btu and 

pounds per 1,000 gallons that are more convenient for making comparison to

conventional emission databases that use these units. 

In subsequent tables, the data presented will be limited to the more important factors and

not include quite as much detail in terms of fuel flows, energ

p

terms will be slightly different appropriate to the fuel and emission factors commonly 

used in the literature. 

 

The stack samples for oil and gas emissions measurements were all conducted at 0.4

cubic feet per minute with a 12.5 dilution ratio. These were selected following a series of 

tests during development of the measurement methodology. Higher and lower dilution

ratios up to 20:1 were tested, which shortened or lengthened the residence time. After 

examining the results it was determined that 12.5:1 was an adequate dilution ration. 

Again, these tests were conducted at approximately isokinetic conditions by selecting a

nozzle to match flow rate to flue gas velocity in the stack. 

18
Table 1 

Oil-fired cast iron boiler, equipped with flame retention head burner in steady state operation

Fuel Type ASTM No. 2 ASTM No. 2 ASTM No. 2 ASTM No. 2 

Fuel Sulfur ppm 1700 1700 1440 1440 

Fuel Flow gph 1.50 1.50 1.50 1.50 

Lbs /hr 10.68 10.68 10.68 10.68 

Btu /lb 19696 19696 19342 19342 

Btu /minute 3506 3506 3442 3442 

kJ /minute 3699 3699 3632 3632 

kg fuel 399.62 323.25 116.58 97.52 

Oxygen % 5.2 4.8 4.9 4.9 

PM 2.5 sample mass mg 204.7 189.2 73.2 59.7 

Run time minutes

Steady State

4950 4004 1444 1208 

Volume sample dcf 1980.0 1601.6 577.6 483.2 

Volume sample m3 56.07 45.35 16.36 13.68 

Volume dcp / lb 234.4 228.7 230.1 230.1 

Volume dcp ft3 / hr 2503.2 2442.0 2457.1 2457.1 

Volume dcp m3/min 1.18 1.15 1.16 1.16 

Total stack volume dcp m3 5847.92 4614.66 1674.49 1400.82 Average STDEV

PM 2.5 mg/dscm 3.7 4.2 4.5 4.4 4.2 0.4

PM 2.5 mg/dscm @ 3% O2 4.2 4.6 5.0 4.9 4.7 0.4

PM 2.5 mg/MJ 1.17 1.30 1.43 1.39 1.32 0.12

PM 2.5 mg/kg 53.4 59.6 64.3 62.7 60.0 4.8

Lbs /MMBtu 0.0027 0.0030 0.0033 0.0032 0.0031 0.0003

Lbs. /1000 gallons 0.38 0.43 0.46 0.45 0.43 0.03

Note: No detailed gaseous emission data were recorded during this of series of tests used

for the development of the PM 2.5 test procedure. The oxygen level was monitored and 

ranged from 5.2-4.9 % with an average of ~ 4.9 %, the CO2 was ~ 12.1 %, and CO was ~ 

6 ppm with a stack temperature of ~370 OF and an efficiency of ~86%. 

 

Figure 2. Cast iron boiler and PM 2.5 Dilution Tunnel Sampler 

19
Table 2 presents the data for a secon ries for the oil-fired cast iron boiler,

e

nt under on off i as based on

Standard 103- Speci , the operating cycle followed a 9.7-

ime and a 33.3-m “off” repeated through a 12-hour test period. 

est runs were completed in this m This w serie sts mentioned 

where BNL had the op ty to est in conjunction with tests conducted

EPA, see Figure 3 US EP of researchers to BNL to 

udy of a residentia red bo he gra ic resu tained by B L 

inary values obtain EPA the iod a ented

boiler was operated clic so no t ility to re rt 

on levels of PM 2.5 with the of stea tate ope n. The dilu on

rovide egrate t as m r unit m of fuel or m ss

energy. The alue eporte a fine ulate emission

g/kg (1.06 ) of ned. mpares very closely to the 

.02 mg/MJ) stand viation g/kg ined by BNL. 

pare favorably with the EPA AP-42 value of 57 mg/

T

oiler, equip ith flam ntion h urner in ic o eration

d test se

quipped with flame retention head burner using ASTM No 2 heating oil with nominal

sulfur conte cyclic operating conditions. The cycl ng pattern w

ASHRAE 103 1193. fically

minute “on” t inute time,

Three t anner. as the s of te

earlier portuni run its t

by the US

conduct a st

. The A had sent a team

l oil-fi iler. T vimetr lts ob N

and prelim ed from

in a cy

during

pattern

test per

there is

re pres

rue ab

in Table 

3. The po

concentrati as case dy s ratio ti

tunnel technique does p an int d resul ass pe ass a

per unit value of final v EPA r d was partic

factor of 49 +/- 5 m mg/MJ fuel bur This co

value, 46 mg/kg (1 with a ard de of 8 m determ

Both values com kg.

able 2

Oil-fired cast iron b ped w e rete ead b cycl p

Fuel Type ASTM No. 2 ASTM No. 2 ASTM No. 2

Fuel Sulfur ppm 1440 1440 1440

Fuel Flow gph 1.50 1.50 1.50 

Lbs. / hr 10.7 10.6 10.8

Btu /lb. 19342 19342 19342

Btu /minute 3457 3431 3493

kJ /minute 3647 3620 3685

Cyclic 

kg fuel 28.62 13.27 13.29 

Oxygen % 3.098 2.819 3.072 

PM 2.5 sample mass mg 15.5 5.6 7.6 

Run time minutes - burner 353 165 162 Average STDEV

PM 2.5 mg/kg 48.7 37.1 51.9 45.9 7.8 

PM 2.5 mg/MJ 1.08 0.82 1.15 1.02 0.17 

US EPA Residential Oil Boiler (ROB) Evaluation of Fine Particulates 

PM 2.5 mg/kg 54.3 47.7 44.0 48.1 5.2 

PM 2.5 mg/MJ 1.20 1.05 0.97 1.06 0.12 

Table 3 

Residential oil cast iron boiler with flame retention burner firing No. 2 fuel (EPA Series)

Reading Number 1 2 2 4 Average Avg. @ 3% O2

Stack Temp. 0 F 386.8 399.3 349.9 343 369.8 * * * * 

Oxygen % 3.6 3.5 3.5 3.5 3.5 * * * * 

CO2 % 13 13.1 13.1 13.1 13.1 * * * * 

CO ppm 6 6 6 6 6 6.2 

Efficiency 86.9 86.7 87.9 88.1 87.4 * * * * 

20
Figure 3. BNL and EPA Staff Conducting Simulations PM 2.5 Measurements

T e

o more than 500- y en analyzed this fuel 

tent of 322-ppm n be seen in Table 4, the fine particulate emission 

fuel was significa wer at /kg (0.4 MJ) when compared to

sured for conventional m distillate heating fuel at 60 mg/kg. 

Table

Oil-fired cast iron boi uipped me rete head burner 

he third set of tests with this boiler was with highway use diesel fuel defined at the tim

as having n ppm sulfur b weight (LS Diesel). Wh

had a sulfur con . As ca

factor for this ntly lo 22 mg 9mg/

that mea iddle

4

ler, eq with fla ntion

sel L l

Fuel Sulfur ppm 332 332 

Fuel Flow gph 1.50 1.50 

Lbs /hr 10.74 10.74 

Btu /lb 19333 19333 

Btu /minute 3461 3461 

J /minute 3651 3651 

Oxygen % 3.5 4.0 

PM 2.5 sample mass mg 27.4 31.1 

Steady State

Fuel Type LS Die S Diese

k

Run time minutes 1372 1795 Average STDEV 

PM 2.5 mg/dscm 1.8 1.5 1.6 0.2 

PM 2.5 mg/dscm @ 3% O2 1.8 1.6 1.7 0.1 

PM 2.5 mg/MJ 0.52 6 0.49 0.04 

PM 2.5 mg/kg 23.3 20.8 2 

Lb 0.0011 00007

0.16 0.01 

0.4

22.0 

s /MMBtu 0.0012 0.0012 0.

Lbs. /1000 gallons 0.15 0.16 

21
Table 5 

Oil-fired cast iron boiler, equipped with flame retention head burner LS fuel

Reading Number 1 2 Average Average @ 3% O2

Stack Temp. 0 F 343 366 354.5 * * * * 

Oxygen % 3.5 3.8 3.7 * * * * 

CO2 % 88.1 12.9 50.5 * * * * 

CO ppm 5 6 6 5.7 

Efficiency 88.1 87.8 88.0 * * * * 

The fourth set of tests (Figure 4) with this boiler utilized ultra low sulfur diesel fuel 

(ULS), then being developed to meet future mandated EPA requirements for a cleaner 

on- highway diesel fuel as introduced in the fall of 2006. BNL had obtained a limited

quantity of fuel meeting ASTM No.1D specifications. The only ULS fuel type available 

at the time was from small pilot plants producing fuel for field trials in the transportation

ector. Unlike the previous tests, the tests using ULS diesel required much longer 

ope for 

ccurate weighing.

7.

s

rating times (~ 3 days) to accumulate a sufficient quantity of particulate (2-5 mg)

a

The measurement results are presented in Table 6. When analyzed the sulfur content of 

the ULS fuel was found to be 11 ppm. The particulate measurement data shown in Table 

6 indicate even further reductions in the particulate emission level, averaging 1.2 mg/kg 

(0.025 mg/MJ) with ULS. Gaseous flue gas constituents are found in Table

Table 6 

Oil-fired cast iron boiler, equipped with flame retention head burner 

Fuel Type ULS Diesel ULS Diesel

Fuel Sulfur ppm 11 11 

Fuel Flow gph 1.50 1.50

Lbs /hr 10.29 10.29

Btu /lb 19865 19865 

Btu /minute 3407 3407

kJ /minute 3594 3594

Oxygen % 4.1 4.5

PM 2.5 sample mass mg 2.0 4.8 

Steady State 

Run time minutes 2624 4150 Average STDEV 

PM 2.5 mg/dscm 67 .02

PM 2.5 mg/dscm @ 3% O2 72 .03

PM 2.5 mg/MJ 020 .031 .025 0.01 

PM 2.5 mg/kg .92 1.43 1.18 

Lbs /MMBtu 000046 .000072 .000059 0.00002 

Lbs. /1000 gallons 062 .0098 .002

0.0 0.102 0.085 0

0.0 0.111 0.092 0

0. 0 0

0 0.36 

0. 0 0

0.0 0 0.0080 0

22
Table 7 

Oil-fired cast iron boiler, equipped with flame retention head burner ULS fuel 

Reading Number 1 2 Average Average @ 3% O2

Stack Temp. 0 F 329 321.3 325.2 * * * * 

Oxygen % 4.1 4.3 4.2 * * * * 

CO2 % 12.6 12.5 12.6 * * * * 

CO ppm 3 3 3 3.2 

Efficiency 94.7 88.5 91.6 * * * * 

Figure 4. Cast iron boiler fueled with ULS diesel fuel 

After sev nits were tested, oiler, equipped with a flame 

retention as re-evaluated g the r techniques developed over

several ea s was to hopefully confirm that earlier findings were repeatable.

The unit was again tested with fuel delivered to the fuel supply tank. This tank is

used for all tests at BNL requiring ASTM No. 2 fuel oil. After the tests were conducted 

fuel resul ived for a sample se for sulfur and heating value analysis. The

fuel sulfur turned out to contain 5870-ppm sulfur. This is well above the ASTM

specificat 2 fuel oil. The heati alue wa ,999 Btu/lb. This fuel was used 

for both s as we under clic on and off use pattern as

presented in Tables 8, 9 and 10. The cy ttern gai f SHRAE

103 Stand

As can be s considerably h e particulate, 203 mg/kg (4.6 

mg/MJ) for steady state and 224 mg/kg (5.1 mg/MJ) for cyclic operatio h this high

sulfur con il. This can be w w ssed and 

found in T e) and Table cy is th ded result

at would have helped to confirm earlier findings. It did however once again support the 

assumption that the tests could be done under steady state conditions rather than 

eral other u the oil-fired cast iron b

head burner w usin efined

rlier tests. Thi

main

ts were rece nt out

ion for No. ng v s 18

a steady state test serie ll as a cy

clic pa was a n that de ined in A

ard 103-1193.

seen there wa igher amount of fin

n, wit

tent No. 2 o compared ith the lo er values as discu

able 1(steady stat 2 (EPA clic). Th was not e inten

th

23
consuming more time testing under cycl ons. It also provided another data point 

confirm

able

O boiler, eq ed lam tion head burner, steady state 

ic conditi

ing a relationship between fuel sulfur content and particulate emissions.

T 8

il-fired cast iron uipp with f e reten

el Type ASTM o. 2 2

57 0 780

el Flow gp

u/Min 34 5 405 Ste

Fu N ASTM No. 2 ASTM No.

Fuel Sulfur ppm 8 5 5780

Fu h 1.49 1.49 1.49 

Bt 0 3 3405

kJ / Min 3592 3592 3592 

Oxygen % 5.45 5.53 5.49 

PM 2.5 sample mass mg 207.5 200.1 237 

ady State

Run time minutes 1375 1300 1490 Average STDEV

PM 2.5 mg/dscm 13.3 13.6 14.0 13.7 0.4 

PM 2.5 mg/dscm @ 3% O2 15.4 15.8 16.3 15.9 0.4 

PM 2.5 mg/MJ 4.47 4.59 4.73 4.6 0.1 

PM 2.5 mg/kg 197.67 202.67 208.89 203.1 5.6 

Lbs /MMBtu 0.0104 0.0107 0.0110 0.011 0.0003

Lbs. /1000 gallons 1.41 1.45 1.49 1.4 0.04 

Table 9 

Oil-fired cast iron boiler, equipped with flame retention burner, steady state, sulfur = 5,780-ppm 

Reading Number 1 2 3 4 5 6 Average Avg. @ 3% O2

Stack Temp. 0 F 390.2 394.2 397.4 395.9 397.3 398.1 395.5 * * * * 

Oxygen % 5.52 5.22 5.23 6.16 5.53 5.46 5.52 * * * *

CO2 % 11.56 11.79 11.78 11.83 11.56 11.61 11.69 * * * * 

CO ppm 2 2.3 1.9 2.4 2.1 2 2 2.5 

NOx ppm 77.7 77.3 77.5 77.6 79.6 79.8 78.3 91.1 

2 ppm 218 228 233 231 224 228 227.0 264.2 

ciency 86.3 86.4 86.3 86.4 86.2 86.2 86.3 * * * * 

Table 10 

Oil-fired cast iron boiler, equipped with flame retention head burner, cyclic operation 

Fuel Type ASTM No. 2 ASTM No. 2 ASTM No. 2 

Fuel Sulfur ppm 5780 5780 5780 

Fuel Flow gph 1.49 1.49 1.49 

Btu/Min 

SO

Effi

3405 3405 3405 

kJ / Min 3592 3592 3592 

Oxygen % 5.35 5.20 5.20 

PM 2.5 sample mass mg 110.7 69.1 99.9 

 Cyclic 

Run time minutes 627 399 637 Average STDEV

PM 2.5 mg/MJ 5.0 5.2 5.1 5.1 0.1 

PM 2.5 mg/kg 220.4 229.8 223.3 224.5 4.8 

Lbs /MMBtu 0.0116 0.0121 0.0118 0.012 0.0003

Lbs. /1000 gallons 1.57 1.64 1.59 1.6 0.03 

24
B. Oil-fired warm air furnace, with flame retention head burner and various fuels

An o ed 

wi etention head oil a p H, a DOE output of

10 d an AFUE rati 81.6% unit w ted with three fuels of

dif ontent (No. 2, LS l and ULS diesel) and in steady state only. The

results are presented in Table 11 through Table e aver ne pa sion

rate with normal heating oil (144 sulfur) was 95.9 mg/kg (2.1 mg/MJ), with LS 

diesel (< 500-ppm sulfur) the emission rate was 24.9 mg/kg (0.51 mg/MJ) and with ULS 

(11 s 2.6 mg/kg (0.06 m .

able 1

ired warm air furnace, with flame retention head burner 

il-fired warm air furnace was the next appliance tested. The furnace was equipp

th a flame r burner with nominal in ut of 0.9 GP

1,000 Btu/hr an ng of . The as tes

fering sulfur c diese

16. Th age fi rticulate emis

0 ppm

ppm) it wa g/MJ)

T 1

Oil-f

Type

Flow gph 0.67 0.67 0.67

Steady State 

Fuel ASTM No. 2 ASTM No. 2 ASTM No. 2 

Fuel Sulfur ppm 1440 1440 1440 

Fuel

Btu /minute 1536 1536 1536 

kJ /minute 1621 1621 1621 

Oxygen % 6.3 6.2 6.2 

PM 2.5 sample mass mg 82.7 71.5 74.0 

1200 1020 1071 Average STDEV 

PM 2.5 mg/dscm 6.2 6.1 6.1 0.1

PM 2.5 mg/dscm @ 3% O2 7.5 7.5 7. 0.02

PM 2.5 mg/MJ 2.1 2.2 2 0.02

PM 2.5 mg/kg 95.7 96.7 95 0.7 

Lbs /MM 0. 0.00004

Lbs. /1000 gallons 0.69 0.69 0. 0.01 

Table

Oil-fired warm air furnace, with f ion head burner with No. 2 Fuel

12

Run time minutes

6.1 

4 7.5 

.1 2.1 

.3 95.9 

Btu 0.0050 0.0050 0049 0.005 

68 0.69 

lame retent

Reading Number 1 2 3 4 5 6 Average Avg. @ 3% O2

0 13.6 420.9 416.1 42 .2 416.7 

en % 6 6.4 6.2

% 1 1 0.9 11.

pm 0 0 0.3 

ency 8 9.3 89.

Stack Temp. F 418.3 411 4 0 * * * * 

Oxyg 6.2 6.3 6.2 .1 6.4 7 * * * * 

CO2 1 11 11 1.2 1 10.9 00 * * * * 

CO p 0 0 0 2 0

Effici 89.7 89.7 89.7 9.3 8 89.3 5 * * * * 

25
Table 13 

Oil-fired warm air furnace, with flame retention head burner 

Fuel Type LS Diesel LS Diesel LS Diesel

Fuel Sulfur ppm * 450 450 450 

Fuel Flow gph 0.67 0.67 0.67 

Btu /minute 1537 1537 1537 

kJ /minute 1622 1622 1622 

Oxygen % 5.52

Steady State 

6.23 6.26 

PM 2.5 sample mass mg 46.8 44.9 48.4 

Run time minutes 1200 1020 1071 

g/dscm 1.6 1.6 1.7 1.6 

PM 2.5 mg/dscm @3%O2 1.8 1.9 .1 1.9 

PM 2.5 mg/MJ 0.5 .54 0

PM 2.5 mg/kg 23 4.5 24.9 

Lbs /MMBtu 0.00 0013 0.0

Lbs. /1000 gallons 0.1 .18 0

ble),

Table

 air furnace, with f ntion burner - LS (<500 ppm sel f

14

Oil-fired warm lame rete head ) die uel

Average STDEV 

PM 2.5 m 0.1 

2 0.1 

2 0 0.48 .51 0.03 

.4 2 26.7 1.7 

12 0. 0.0011 012 0.00007 

7 0 0.19 .18 0.01 

* Fuel sulfur taken as 450-ppm (80% of maximum allowa likely lower. 

Reading Number 1 2 3 4 5 6 Avg. Avg. @ 3% O2

Stack Temp. 0 F 427.9 422.4 416.2 404.2 426.8 437.4 422.5 * * * * 

Oxygen % 5.63 5.43 5.45 5.65 5.4 5.44 5.50 * * * *

CO2 % 11.48 11.63 11.62 11.46 11.65 11.63 11.58 * * * * 

CO ppm 0.6 0 0.7 0.1 0.1 0.1 0 0.3 

NOx ppm 100.1 100.7 98.1 93.3 103.6 102.7 99.8 115.9

SO2 ppm 9 9 9 9 9 9 9.0 10.5

Efficiency 85.4 85.7 85.7 86 85.3 86 85.7 * * * *

26
-fired warm air f t t ad burner 

Table 15 

Oil urnace, wi h flame re ention he

Fuel Type ULS D1 ULS D1

Fuel Sulfur ppm 11 11

Fuel Flow gph 0.62 0.62

Btu /minute 1411 1411

kJ /minute 1489 1489

Oxygen % 6.5 6.4

PM 2.5 sample mass mg 9.0 6.2

Steady State 

Run time minutes 4167 4077 Average STDEV

PM 2.5 mg/dscm 0.2 0.04

PM 2.5 mg 0.2 0.05

PM 2.5 m 0.05 0.06 0.01

PM 2.5 2.1 2.6 0.6

Lbs /MMBtu 0.00015 0.00011 0.00013 0.00003

Lbs. /1000 gallons 0.022 0.015 0.018 0.005 

0.2 0.1 

/dscm @3%O2 0.2 0.2 

g/MJ 0.07 

mg/kg 3.0

Note: Two runs only, fuel availability constrained the number of tests 

Table 16 

Oil-fired warm air furnace, with flame retention head burner with ULS fuel 

Reading Number 1 2 3 4 5 6 Average Avg, @ 3% O2

Stack Temp. 0 F 402.4 404 396 405.4 400.3 399.9 40

Oxygen % 6.3 6.2 6.4 6.7 6.2 6.4 6.3

CO2 % 11 11 10.9 10.7 11 10.9 10

CO ppm 0 0 0 0 0 0 0 

Efficiency 86.2 85.8 86.4 85.7 86.6 85.6 

1.3 *** 

7 *** 

.92 *** 

0 

86.1 *** 

27
C. Gas-fired cast iron boiler, atmospheric burner and electronic spark ignition 

he third heating appliance tested was a mid-efficiency natural gas-fired hydronic boiler 

esigned for an input of 126,000 Btu/hr with a 104,000 Btu/hr output and an 81% AFUE, 

see Figure 5. The boiler was equipped with an atmospheric burner, intermittent pilot and 

vent damper. T ons as well as

cyclic conditions following the ASHRA he case with the

ULS diesel fired appliance tests, this boiler required long periods of run time to 

accumulate antity of partic ma accurate weighing. Even with 

these long r 4 to 7 days) samp gh sure the range of

roughly 3 to ms. The results are n i es 17, 18 and 19. Under steady 

state operation the particulate emission ra vera 0.90 mg/kg (0.016 mg/MJ) and 

under a cyclic operating pattern it averaged 2.7 mg/kg (0.049 mg/MJ). 

T

d

he gas boiler was tested under steady state operating conditi

E 103 cycle pattern. As was t

a sufficient qu ulate ss for

un times (~ le wei ts mea d were only in

 6 milligra show n Tabl

te a ged

Figure 5. Atmosphe ed hydronic boiler

Table 17 

Gas-fired sectional cast iron boiler, atmospheric burner and electronic spark ignition 

ric gas-fir

Fuel Type Natural Gas Natural Gas Natural Gas

Fuel Sulfur ppm 10.5 10.5 10.5 

Fuel Flow cubic ft /minute 1.934 1.934 1.934 

Btu/Min 1940 1940 1940 

kJ / Min 2047 2047 2047

Oxygen % 8.24 8.20 8.20 

PM 2.5 sample mass mg 4.7 5.7 2.7 

 Steady State 

Run time minutes 9825 9909 6145 Average STDEV 

PM 2.5 mg/dscm 0.042 0.051 0.039 0.04 0.01 

PM mg/dscm @ 3% O2 0.060 0.072 0.055 0.06 0.01 

PM 2.5 mg/MJ 0.016 0.019 0.014 0.016 0.002 

PM 2.5 mg/kg 0.87 1.04 0.80 0.90 0.1 

Lbs /MMBtu 0.000037 0.000044 0.000034 0.000038 0.000005

Lbs. /MM cubic foot 0.037 0.044 0.034 0.038 0.005 

28
Table 18 

Gas-fired sectional cast iron boiler, atmospheric burner and electronic spark ignition 

Reading Number 1 2 3 4 5 6 Avg. Avg. @ 3% O2

Stack Temp. 0 F 491.9 506.2 507.8 505.2 498.6 499.2 501.5 * * * * 

Oxygen % 8.26 8.15 8.31 8.29 8.27 8.19 8.25 * * * * 

CO2 % 7.09 7.15 7.06 7.07 7.11 7.12 7.10 * * * * 

CO ppm 0.7 0.7 0.7 1 0.4 0.6 1 1.0 

NOx ppm 92.9 97 91.9 92.7 99.9 100.1 95.8 135.4 

SO2 ppm 0 0 0 0 0 0 0.0 0.0 

Efficiency 79.5 79.2 78.9 79 79.3 79.3 79.2 * * * * 

Table 19 

Gas-fired sectional cast iron boiler, atmospheric burner and electronic spark ignition 

Fuel Type Natural Gas Natural Gas Natural Gas

Fuel Sulfur ppm 10.5 10.5 10.5

Fuel Flow cubic ft /minute 2.010 2.010 2.010 

Btu/Min 2016 2016 2016 

kJ / Min 2127 2127 2127 

xygen % 7.95 7.95 7.95

M 2.5 sample ma 3.9 

un time minutes

.047 .050 .051 49 0.002 

.57 .74 .79

bs /MMBtu 0011 0012 0012

bs. /MM cubic foot 11 .12 .12

O

P ss mg 6.2 3.8 

 Cyclic Operation 

R 4297 2470 2489 Average STDEV 

PM 2.5 mg/MJ 0 0 0 0.0

PM 2.5 mg/kg 2 2 2 2.70 0.1 

L 0.0 0.0 0.0 0.00011 0.000005

L 0. 0 0 0.11 0.005 

29
D. Gas-fired warm air furnace, in-shot induced draft burner with spark ignition 

he third heating appliance tested was a mid-efficiency natural gas-fired warm air 

urnace designed for an input of 125,000 Btu/hr with a 99,000 Btu/hr output and an 81% 

FUE, see Figure 6. This unit included in-shot induced draft burners and electric spark 

nition. The gas furnace was tested under steady state operating conditions as well as 

cyclic conditions following the ASHRA

bo e

weighing. Even with these long run times (~ 4 d s

nly in o 2 m m e s are n in

21 and 22. U te ta ra he cu m n rat ged

/kg (0.011 mg/M nd r li ra a t ged /kg

g/MJ). 

e

d warm air furn duced dr burn and ctro park ignition 

T

f

A

ig

E 103 cycle pattern. This unit like the gas-fired 

iler required long periods of run time to accumulate a sufficient quantity of particulat

mass for accurate ays) sample weight

measured were o the range of r ughly to 4 illigra s. Th result show

Tables 20, nder s ady s te ope tion t parti late e issio e avera

0.63 mg

(0.0

J) a unde a cyc c ope ting p ttern i avera 3.2 mg

58 m

Tabl 20

Gas-fire ace, in-shot in aft er ele nic s

Fuel Type Natural Gas Natural Gas Natural Gas

Fuel Sulfur ppm 10.5 10.5 10.5 

Fuel Flow cubic ft /minute 1.925 1.925 1.925 

Btu/Min 1931 1931 1931 

kJ / Min 2037 2037 2037 

Oxygen % 8.35 8.30 8.59 

PM 2.5 sample mass mg 2.0 1.8 2.2 

 Steady State 

Run time minutes 5630 5928 5996 Average STDEV 

PM 2.5 mg/dscm 0.031 0.027 0.032 0.030 0.003 

PM mg/dscm @ 3% O2 0.045 0.038 0.047 0.043 0.005 

PM 2.5 mg/MJ 0.012 0.010 0.012 

PM 2.5 mg/kg 0.65 0.55 0.69

Lbs /MMBtu 000028 000023 00029

Lbs. /MM cubic foot 0.028 .024 .029 0.027 0.003 

21

Gas-fired warm air furna raft nd el

eading Number 3 5 Average Avg. @ 3% O2

ack Temp. 0 F 463.8 454.4 .1 7 * * * * 

xygen % 8.34 8.57

O2 % 7.04 6.91 89 7.00 * * * * 

O ppm 5.8 6 5.8 8.3 

0.011 0.001 

0.63 0.1 

0. 0. 0.0 0.000027 0.000003

0 0

Table

ce, in-shot induced d burner a ectronic spark ignition 

R 1 2 4 6

St 455.2 453.5 464.2 455 457.

O 8.37 8.34 8.29 8.61 8.42 * * * * 

C 7.03 7.05 7.07 6.

C 5.8 5.8 5.4 6 

NOx ppm 57.3 55.8 56.3 56.1 54.7 54.7 55.8 80.1 

SO2 ppm 0 0 0 0 0 0 0.0 0.0 

Efficiency 80.2 80.3 80.1 80.1 80.1 80.1 80.2 * * * * 

30
Figure 6. Gas-fired warm air furnac in-sho ced draft burner

Tabl

air furnace, in-shot induced urner ectro

e with t indu

e 22

Gas-fired warm draft b and el nic spark ignition 

Fuel Type Natural Gas Natural Gas Natural Gas

Fuel Sulfur ppm 10.5 10.5 10.5

Fuel Flow cubic ft /minute 1.950 1.950 1.950

Btu/Min 1956 1956 1956 

kJ / Min 2064 2064 2064 

Oxygen % 9.55 9.55 9.55 

as g 4.0 2.2 2.4 

Cyclic Operation 

PM 2.5 sample m s m

Run time minutes 1896 1641 1896 Average STDEV

PM 2.5 mg/MJ 0.078 0.049 0.047 0.058 0.017

PM 2.5 mg/kg 4.29 2.72 2.57 3.19 0.9 

Lbs /MMBtu 0.00018 0.00012 0.00011 0.00013 0.000040

Lbs. /MM cubic foot 0.18 0.12 0.11 0.14 0.040

31
E. Gas-fired condensing aluminum boiler, premixed power burner, spark ignition

he condensing aluminum gas-fired boiler (see Figure 7) was designed to modulate its 

put rate from 80,000 up to 200,000 Btu/hr with a thermal output from 76,000 up to 

190,000 with an AFUE rating of 95%. Tests were conducted in steady state only due to 

the complexity of the automatic modulating control included to enhance the unit’s 

efficiency. The unit was operated at an input rate of approximately 115,000 Btu/hr. The 

particulate emission rate averaged 2.0 mg/kg of fuel (0.36 mg/MJ) as shown in Table 23.

The results of the gaseous emissions measurements can be found in Table 24. 

T

in

Figure 7. Gas- ensing boiler

a

ondensing aluminum boiler, premixed pow ner, spark ignition 

fired cond

T ble 23

Gas-fired c er bur

Fuel Type Natural Gas Natural Gas Natural Gas

Fuel Sulfur ppm 10.5 10.5 10.5

Fuel Flow cubic ft /minute 1.925 1.925 1.925 

Btu/Min 1312 1288 1290 

kJ / Min 1384 1359 1361

Oxygen % 5.86 5.86 5.92

PM 2.5 sample mass mg 

Steady State 

12.1 10.3 7.1

Run time minutes 8562 8462 5963 rage EV

PM 2.5 mg/dscm 0.12 0.11 0.11 0.11 0.01 

PM mg/dscm @ 3% O2 0.15 .13 .13 .13 .01

Ave STD

0 0 0 0

PM 2.5 mg/MJ 0.039 0.034 0.033 0.036 0.003 

PM 2.5 mg/kg 2.17 1.87 1.83 1.96 0.2 

Lbs /MMBtu 0.000092 0.000079 0.000077 0.000083 0.000008

Lbs. /MM cubic foot 0.092 0.079 0.078 0.083 0.008 

32
Table 24 

Gas-fired condensing aluminum boiler, premixed power burner, spark ignition 

Reading Number 1 2 3 4 5 6 Avg. Avg. @ 3% O2

Stack Temperature 0F 99.2 99.2 99.1 119.3 119 119.2 109.2 * * * * 

Oxygen % 5.9 5.87 5.86 6.06 5.93 5.91 5.92 * * * * 

CO2 % 8.41 8.42 8.43 8.32 8.39 8.4 8.40 * * * * 

CO ppm 2.7 2.6 2.6 2 2.1 1.8 2 2.7 

NOx ppm 8.9 9 9.2 8.5 9.1 9 9.0 10.7 

SO2 ppm 2 1 1 1 1 1 1.0 1.2 

Efficiency 89.7 89.7 89.7 89.3 89.3 89.3 89.5 * * * * 

F. Oil-fired condensing steel boiler, flame retention head burner, with various fuels 

The oil-fired condensing boiler (see Figure 8) was designed with two heat exchangers.

The primary heat exchanger is a unitized thick-shelled carbon steel boiler with

combustion chamber and integral steel heat exchanger with a system of removable 

baffles. Hot gases exiting the primary heat exchanger then proceed directly to the 

secondary heat exchanger fabricated from corrosion resistant stainless steel with a 

condensate drain. The unit is fired with a high static pressure flame retention head burner 

with a nominal input of 81,250 Btu/hr, an output rating of 76,000 Btu/hr and an AFUE 

rating of 95%. This unit was fired with three different fuels including No. 2 heating fuel,

ULS diesel and a soybean derived biodiesel meeting ASTM specifications as a blending 

product for use in diesel or heating fuels, see Tables 25 through 30. Particulate emissions 

averaged 109.8 mg/kg (2.5 mg/MJ) for No. 2 heating oil, 1.34 mg/kg (0.030 m /MJ) for

ULS diesel and 67.8 m sults determined when 

iring biodiesel was quite unexpected and unexplainable based on prior conceptions. As a

result yet another boiler of cast iron construction (not a condensing unit) was tested and

the da same

bio had an average .1 mg/kg (0.3 mg/MJ) 

which was still higher than typica es for iesel b ch closer to that expected

for nt fu is will cusse er in the conclusions and

rec ation sections of this .

Table

nden iler with ASTM No. 2 fuel – steady state 

g

g/kg (1.7 mg/MJ) for biodiesel. The re

f

ta is presented in Tables 31 and 32. This unit, see Figure 9, fired with the

diesel fuel particulate emission rate of only 12

l valu ULS d ut mu

an ultra low sulfur conte el. Th be dis d furth

ommend report

25

Oil-fired co sing bo

ding Number 4 Avg. Avg.

ck Temperature F

0 .8 167.8 169.4 .8 16

gen % 3.8 7 3.90 4.25 6 4

2 % 80 1 12.52 .58 12.65

ppm 6 1.0 7 1.7 

x ppm 82.5 82 85.4 85.6 85.7 84.3

2 ppm 3 69 9 6

Rea 1 2 3 7 8 @ 3% O2

Sta 162.4 161 169 170.5 7.9 * * * * 

Oxy 8 3.8 4.1 4.2 .08 * * * * 

CO 12.79 12. 2.78 12 12.6 * * * * 

CO 2.7 2. 2.9 0. 1.1 2 

NO 82.5 .2 90 

SO 53 5 51 6 69.0 2 66 

Efficiency 91.9 91.9 91.8 91.6 91.6 91.6 91.7 * * * * 

33
Table 26 

Oil-fired condensing steel boiler tested with flame retention head burner

el Type AS No. AS No. AS M N . 2

1900 

el Flow gp 0.57

tu /minute

/minute 

xygen % .9 3.9 3.9

Fu TM 2 TM 2 T o

Fuel Sulfur ppm 1900 1900 

Fu h 0.56 0.57 

B 1286 1307 1317 

kJ 1357 1379 1390 

O 3

PM 2.5 sample mass mg 142.5 143.0 137.5 

Steady State 

Run time minutes 1531 1490 1480 Average STDEV

PM 2.5 mg/dscm 8.2 8.5 8.2 8.3 0.2 

PM 2.5 mg/dscm @ 3% O2 8.6 8.9 8.6 8.7 0.2 

PM 2.5 mg/MJ 2.4 2.5 2.4 2.5 0.05 

PM 2.5 mg/kg 108.7 112.2 108.6 109.8 2.0 

Lbs /MMBtu 0.0057 0.0058 0.0056 0.0057 0.0001

Lbs. /1000 gallons 0.78 0.81 0.78 0.79 0.01 

 Figure 8. Oil-fired condensing steel boiler during PM 2.5 dilution tunnel testing

34
Table 27 

Oil-fired condensing steel boiler tested with flame retention head burner 

Fuel Type ULS ULS ULS 

Fuel Sulfur ppm 37 37 37 

Fuel Flow gph 0.58 0.57 0.55 

Btu /minute 1330 1309 1254

kJ /minute 1404 1382 1324

Oxygen % 4.36 3.92 3.87

PM 2.5 sample mass mg 5.4

Steady State 

7.4 6.2 

Run time minutes 5675 5862 5546 Average 

PM 2.5 mg/dscm 0.12 0.09 9

PM 2.5 mg/dscm @3%O2 0.12 0.10 9 0 0.02

PM 2.5 mg/MJ 0.03 028 0.005

PM 2.5 mg/kg 1.6 .3

Lbs /MMBtu 0065 60 0.00001

Lbs. /1000 gallons 0.011 .009 8 0.002

STDEV 

0.0 0.10 0.02 

0.0 0.1

6 0. 0.026 0.030 

1 1.2 1.34 0.2 

0.000083 0.00 0.0000 0.00007

0 0.00 0.010

Table 28 

Oil-fired condensing boiler with ULS Fuel –steady state 

Reading Number 1 2 3 4 5 6 Avg. Avg. @ 3% O2

Stack Temperature 0F 161.4 168.4 188.2 183.1 173.4 172.1 174.4 * * * * 

Oxygen % 4.36 4.36 3.96 3.9 3.85 3.82 4.04 * * * * 

CO2 % 12.43 12.43 12.74 12.77 12.82 12.84 12.67 * * * * 

CO ppm 2.3 2.6 2.8 2.8 3.3 3.1 2.8 3.0 

NOx ppm 66.6 66.6 64.3 64.8 65.1 65.2 65.4 69.0 

SO2 ppm 1 1 1 1 1 1 1 1.1 

Efficiency % 92.1 91.9 91.3 91.5 91.7 91.8 91.7 * * * * 

35
able 2

ndensing steel boiler tested flame tion head burner 

T 9

Oil-fired co with reten

el Type Biodiesel 

el Sulfur pp 164 164 164

el Flow gph 0.59 0.59 0.59

u /minute 1264 1256 1258 

/minute 1334 1325 1327

xygen % 4.4 4 3.8

2.5 sample mass mg 198.9 94.4 94.0

un time minutes 3240 1579 1399 Average STDE

2.5 mg/dscm 5.4 5.3 5.9 5.5 0.

5.9 5.6 6.2 5.9 0.3

2.5 mg/MJ 1.7 1.6 1.8 1.7 0.09

Fu Biodiesel Biodiesel 

Fu m 

Fu

Bt

kJ

O

PM

Steady State 

R V

PM 3

PM 2.5 mg/dscm @3%O2

PM

PM 2.5 mg/kg 67.6 64.3 71.4 67.8 3.6 

Lbs /MMBtu 0.0039 0.0037 0.0041 0.0039 0.0002 

Lbs. /1000 gallons 0.49 0.47 0.52 0.50 0.03 

e

Oil-fired condensing m tio e Bi Fu ady st

Tabl

e n

30

steel boiler, fla rete n burn r with odiesel el –ste ate

Reading Number 1 2 3 4 5 6 g. 2

Stack Temperature 0F165.6 174.2 201.3 200.8 112.1 112.5 1.1 * * * *

Oxygen % 4.35 4.3 4.18 4.17 3.8 3.76 .09 * *

Av Avg. @ 3% O

16

4 * *

CO2 % 12.44 12.47 12.57 12.58 12.85 12.88 12.63 * * * * 

CO ppm 1.6 1.4 0.6 0.3 2.1 1.8 1.3 1.4 

NOx ppm 59.7 60.3 64 64.1 61.1 61.7 61.8 65.8 

SO2 ppm 4 4 7 7 8 9 6.5 6.9 

Efficiency % 91.7 91.6 90.8 90.8 93 93 91.8 * * * * 

36
Table 31 

Oil-fired cast iron boiler tested with flame retention head burner 

Fuel Type Biodiesel Biodiesel Biodiesel 

Fuel Sulfur ppm 164 164 164 

Fuel Flow gph 0.766 0.766 0.766 

Btu /minute 1629 1629 1629 

kJ /minute 1719 1719 1719

Oxygen % 7.10 6.69 6.35 

PM 2.5 sample mass mg 

Steady State 

3.3 3.2 4.8

Run time minutes 390 400 405

PM 2.5 mg/dscm 0.75 1.05

PM 2.5 mg/dscm @ 3% O2 0.97 0.89 1.29 

PM 2.5 mg/MJ 0.27 0.25 0.36 0.3 0.06 

PM 2.5 mg/kg 11.14 10.23 12.1 2.4 

Lbs /MMBtu 

Lbs. /1000 gallons 0.081 0.075 0.09 0.02 

Tab 32

l-fired convention ast ir iler, f with iesel

Average STDEV

0.71 0.8 0.2 

1.0 0.2 

14.80 

0.00064 0.00059 0.00085 0.0007 0.0001 

0.108 

le

Oi al residential c on bo lame retention biod fuel

Reading Number 1 2 3 4 5 6 Avg. Avg. @ 3% O2

Stack Temperature 0F 360.4 369.1 369.3 369.3 364.6 368.1 366.8 * * * * 

Oxygen % 7.12 7.13 6.61 6.77 6.36 6.34 6.72 * * * * 

CO2 % 10.37 10.36 10.75 10.63 10.93 10.95 10.67 * * * * 

CO ppm 0 0 0 0 0 0.3 0 0 

NOx ppm 117.5 118.4 117.6 116.6 110.6 109.5 115.0 145.2 

SO2 ppm 10 10 10 10 11 12 10.5 13.3 

Efficiency % 86 85.8 86 86 86.4 86.5 8 * * * *

Figure 9. Cast iron boiler fired with biodiesel for comparison purposes 

6.1

37
G. Oil-fired condensing furnace with ntion head burner, various fuels

Th ntion head burner e i re 10) 

was also designed with two heat exchangers. The first non-condensing heat exchanger 

(pr ilt from a common stainless steel. The condensing heat exchanger 

(secondary) was fabricated from a very corro esista inless steel (alloy AL294C), which is extremely resistant to the corrosion environment expected from use with 

No. 2 (relatively high in sulfur content). The model tested was designed to fire at 0.5 

GP of 75,000 Btu/hr with a output of 73,500 Btu/hr and a AFUE of 95%. 

Th ree different fuels, No 2 oil (1,440 ppm sulfur), LS diesel (322 

ppm l (11 ppm sulfu fin rticula iss r red

and the flue gas analysis data are presented in Tables 33 through 38. 

flame rete

e flame rete quipped o l-fired condensing furnace (see Figu

imary) was bu

sive r nt sta

H, an input rated

e unit was tested with th

) and ULS diese r). The e pa te em ion facto s measu

Figure 10. Oil ed ns wa E rat

Table 33 

Oil-fired condensing warm air furnace, flame retention head burner 

-fir conde ing rm air furnace, 95% AFU ing

Fuel Type ASTM No. 2 ASTM No. 2 ASTM No. 2

Fuel Sulfur ppm 1440 1440 1440 

Fuel Flow gph 0.48 0.48 0.48 

Btu /minute 1114 1114 1114 

Kj /minute 1175 1175 1175 

Oxygen % 4.7 5.1 3.1 

PM 2.5 sample mass mg 152.1 106.3 91.3 

Steady State 

Run time minutes 2687 1578 1363 Average STDEV

PM 2.5 mg/dscm 5.0 5.9 5.9 5.6 0.5 

PM 2.5 mg/dscm @ 3% O2 5.5 6.7 5.9 6.1 0.6 

PM 2.5 mg/MJ 1.5 1.9 2.0 1.8 0.24 

PM 2.5 mg/kg 70.9 86.5 76.3 77.9 7.9 

Lbs /MMBtu 0.0036 0.0044 0.0047 0.0042 0.0006

Lbs. /1000 gallons 0.51 0.62 0.55 0.56 0.06 

38
Table 34 

Oil condensing warm air furnace, with flame retention head burner with No. 2 fuel 

Reading Number 1 2 3 4 5 6 Average Avg. @ 3% O2

Stack Temp. 0 F 91.2 91.2 90.5 90.5 89.7 87.4 90.1 * * * * 

Oxygen % 4 4.7 4.6 4.7 5.1 5 4.7 * * * * 

CO2 % 12.6 12.2 12.2 12.2 11.9 12.7 12.3 * * * * 

CO ppm 8 8 2 1 2 1 4 4 

Efficiency 93.6 93.6 93.6 93.6 93.3 94.6 93.7 * * * * 

Table 35 

Oil condensing warm air furnace with flame retention head burner 

Fuel Type LS Diesel LS Diesel

Fuel Sulfur ppm 332 332 

Fuel Flow gph 0.48 0.48 

Btu /minute 1080 1080 

kJ /minute 1139 1139 

Oxygen % 5.3 5.5 

PM 2.5 sample mass mg 26.1 49.5 

Steady State 

Run time minutes 1523 2889 Average STDEV 

PM 2.5 mg/dscm 1.5 1.5 1.5 0.0002 

PM 2.5 mg/dscm @ 3% O2 1.7 1.8 1.7 0.02 

PM 2.5 mg/MJ 0.496 0.502 0.499 0.005 

PM 2.5 mg/kg 22.3 22.6 22.4 0.2 

Lbs /MMBtu 0.00115 0.00117 0.00116 0.00001 

Lbs. /1000 gallons 0.158 0.160 0.159 0.001 

Note: Two runs only, fuel availability constrained the number of tests 

ng warm air furn ith flame retention h rner with LS fuel 

Table 36

Oil condensi ace, w ead bu

Reading Number Average @ 3% O2

Stack Temp. 0 F 85 85.4 85.2 * *

Oxygen % 5.4 5.5 5.5 

CO2 % 

CO ppm 2 0 1 1.2 

Efficiency 

1 2 Average 

* *

* * * * 

12.4 12.3 12.4 * * * * 

94.7 94.7 94.7 * * * * 

39
Table 37 

Oil condensing warm air furnace with flame retention head burner 

Fuel Type ULS ULS 

Fuel Sulfur ppm 11 11

gp 0.45 0.4

ute 1015 101

% 5.2 6.5

Steady State 

Fuel Flow h 5

Btu /min 5

kJ /minute 1071 1071 

Oxygen

PM 2.5 sample mass mg 4.1 2.2 

 

Run time minutes 5400 4330 Average STDEV 

PM 2.5 mg/dscm 0.07 0.04 0.06 0.02 

PM 2.5 mg/dscm @ 3% O2 0.08 0.06 0.07 0.01 

PM 2.5 mg/MJ 0.013 0.015 0.014 0.00 

PM 2.5 mg/kg 0.98 0.72 

Lbs /MMBtu .0000 0004

Lbs. /1000 gallons 0.01 .01

Note: Two runs only, fuel availability constrained the number of tests

condensing warm ith fl tent rner ith ULS f

Number 1 2 3 4 6 Avg. @

mp. 0 F 86.3 84.6 91.6 87.4 86.4 * *

6.3 5 5.9 .32 * * * * 

11 11.9 11 7 11.3 11.70 * *

4 2 1 2 3.9 

93.5 93.5 93.4 93.5 93.5 93.5 93.5 *

0.85 0.2 

0 3 0.0 0.00003 0.000003 

0 0.006 0.001 

Table 38 

Oil air furnace, w ame re ion bu w uel 

Reading 5 Average 3% O2

Stack Te 83.5 85 * *

Oxygen % 4.4 5 5.3 5

CO2 % 12.4 11.9 . * *

CO ppm 3 2 0

Efficiency * * *

H. Oil-fired cast iron boiler with combustion gas recirculation burner (blue flame) 

The c in a

conventional cast iron sectional h roni nit, as shown in Figure 10. The

tes esented in Tables nd 4 e particulate e ns were very

similar to those obtained for various units equipped with flame retention head burners 

(ye ). The gaseous em ns reflec decrease in NO compared to

the conventional yellow flame burne the United States. This unit was tested 

using ULS fuel only. Further testing was not warranted based on budget constraints and 

the small installed in ry is ty oil burner tech in the United 

tates. Projections for future sales are also very small in the U.S. market. 

ombustion gas recirculation (blue flame) burner (see Figure 11) was evaluated

yd c u the same boiler 

ts results are pr 39 a 0. Th missio

llow flame issio data ts a x when

r used in

extremely vento of th pe of nology

S

40
Table 39 

Cast iron boiler with combustion gas recirculation burner with ULS 

ement 2 3

emperature OF 317.3 

% 3.89 3.85 3.96 

2.79 12.82

3.1 3.3

m 45.2 45 45.5

m 0 0 0 

cy % 88.2 8.5 88.8 88.5

fired cast iro bustion gas recirculation b rner and U

Type UL S

lfur ppm 37 37 37 

Measur 1 Average Avg, @ 3% O2

Stack T 337.4 328.8 327.8 *** 

Oxygen 4.14 *** 

CO2 % 12.6 1 12.74 *** 

CO ppm 1.6 2.7 3.3 

NOx pp 45.2 55.8 

SO2 pp 0 0 

Efficien 8 *** 

Table 40 

Oil- n boiler with com u LS

Fuel ULS S UL

Fuel Su

Fuel Flow gph 0.67 0.65 0.68 

Btu /minute 1535 1485 1563 

Kj /minute 1619 1567 1649 

Oxygen % 4.0 4.0 4.0 

P

Steady State 

M 2.5 sample mass mg 7.3 7.6 7.1 

Run time minutes 4518 5751 4674 Average STDEV 

PM 2.5 mg/dscm 0.12 0.13 0.01 

PM 2.5 mg/dscm @3%O2 2 0.14 0.01 

PM 2.5 mg/MJ 0.043 0.035 0.040 0.039 0.004 

PM 2. 0.2 

Lbs /MMBtu 0.00010 0.00008 0.00009 0 .00001 

0.14 0.13 

0.15 0.1 0.14 

5 mg/kg 1.9 1.6 1.8 1.8 

.00009 0

Lbs. /1000 gallons 0.014 0.011 0.013 0.013 0.001 

Figure 11. Combustion gas recirculation (blue flame) burner 

41
I. Wood pe gnition 

The ev wa for im ut of 4. unds per

hou F 12. t co nts eat exchanger were

constructed primarily out of heavy gauge steel sheet wit uter cas of lighter

gau l. The design in sev otors driving the fuel fed auger, air 

circ wer and power blowe e unit equi with a control board 

that included an adjustment knob that varied the fuel input rate by changing the auger 

on/o nother knob on ntrol d was to control the air blower speed 

that he forced convec e heat tr m he stov y circulat room air

thro xchanger ba to th m. T t’s d incorpo d a pellet

ed auger that fed fuel pellets to the top of a downward chute that then dropped the 

pellets onto the top of the burner grate. The burn grate was open on the bottom allowing 

the maj bed of

fuel. Th ection

facing the stove’s glass door) and large ter one 

being very hot air jet that pr ed for automated ignition. This air jet 

flowing over an electric hot surface ignite ts the d pellets to the point of

ignition. The unit was also equipped with com n air by yet

anothe with an adjustab per raft c . It could be sidewall or 

vertically vented. The unit was only tested at the maximu put rating determined to be 

4.3 po the s gs us ring th ts. The stove was operated 

under conditions uge ol for 1

second 5 seconds r ng in mewh lic b atte is was

most evident in the wide swings in CO meas which esult han air-fuel

ratio changing over short time periods. The NOx level range on the other hand was 

relativ ost likely refle the that the est po n of bustion

NOx e related to th O tho n ound

nitrog x format rtic missi s w er in two 

size categories, smaller than 2.5 microns and those larger than 2.5 microns. The results 

are presented in Table 41 and the gaseous emissions data recorded are presented in Table 

42. 

llet stove; drop down over fed, open burner grate, and electric i

first wood pellet stove

r (~38,000 Btu/hr), see

aluated

igure

s rated

The ho

a max

mpone

um inp

and h

5 po

metal h an o ing

ge meta cluded eral m

ulation blo draft r. Th was pped

ff cycle. A the co boar used

provides t tiv ansfer fro t e b ing

ugh the heat e ck into e roo he uni esign rate

fe

or portion of the forced combustion air to flow upward through the burning

e burner grate also had eight air inlet holes across its front surface (dir

three r holes on the backside with the cen

the inlet for the ovid

r hea air an

forced bustio flow supplied

r blower le dam for d ontrol

m in

unds per hour based on ettin ed du e tes

near steady state . The a r pellet feed contr actually cycles on

and off for 1.1 esulti a so at cyc urn p rn. Th

ured, is a r the c ging

ely narrow m cting fact larg rtio com

missions are ermal N x versus se portio s related to fuel b

en and prompt NO ion. Pa ulate e on rate ere det mined

Figure 12. Pellet stove with drop down over fed, open burner grate, electric ignition 

42
Table 41 

Wood pellet stove, drop down over fed, open burner grate, electric ignition 

Fine Particulate (PM 2.5)

Lbs /hr 4.3 4.3 4.3 

Btu /minute 569 569 569 

Kj /minute 601 601 601 

Oxygen % 13.25 13.25 13.25 

PM 2.5 sample mass mg 11.1 15.8 14.8 

Steady State 

Operation 

(8001 Btu/lb) 

Run time minutes 75 60 90 Average STDEV 

PM 2.5 mg/dscm 16 22 15 18 4 

PM mg/dscm @ 3% O2 84 123 77 95 25 

PM 2.5 mg/MJ 28 39 24 30 8 

PM 2.5 mg/kg 519 718 447 562 140 

Lbs /MMBtu 0.065 0.090 0.056 0.070 0.018 

Lb /Ton 1.04 1.44 0.89 1.12 0.28 

Gram particulate /hr 1.00 1.03 0.93 0.99 0.05 

 

Larger Particulate (>PM 2.5) Cyclone Catch

PM > 2.5 sample mass mg 6.1 7.5 5.1 Average STDEV 

PM > 2.5 mg/dscm 14 21 16 17 4 

PM > mg/dscm @ 3% O2 71 112 81 88 21 

PM > 2.5 mg/MJ 24 35 26 28 6 

PM > 2.5 mg/kg 444 655 475 524 114 

Lbs /MMBtu 0.056 0.082 0.059 0.066 0.014 

Lb /Ton 0.89 1.31 0.95 1.05 0.23 

Gram particulate /hr 0.86 1.27 0.92 1.02 0.22 

Table 42 

Wood pellet stove, over feed, open grate, electric ignition 

Measurement Range Average Avg. @ 3% Oxygen 

Temperature OF 387.1-420.5 403.1   

Oxygen % 16.70-18.10 17.5 ** ** 

CO2 % 2.72-4.06 3.29   

NOx ppm 18.3-27.6 22.1 116.4 

CO ppm 60.7-187.4 117.7 619.7 

SO2 ppm 0-2 1 5.3 

Efficiency % 48.7-64.4 58.5 ** ** 

43
J. Pellet stove, over fed burner, enclos an burn grate, electric ignition

The ing

automatic ignition based a on v urface igniter. It was fabricated

iron as well as heavy gauge steel shee inco ted a self-cleaning feature

d yet another electric motor. sec nit n input 00 to 

/hour or about 1.8 - 7.5 pounds of fuel per hour. This unit was operated at 

same fuel input as the ot ood pellet stoves to make a more direct 

of performance. The actual ns co d in th 400 –

e s eaning ductile iron firepot

a microprocessor control tha lowed r c g es

uel type. In addition to emium ood ets (< 1% ash content) this 

urn standard grad d high ash content wood pellets, shelled field 

and other biomass fuels with higher ash contents like wheat and black oil 

ds. Like the previous uni pe are trans d from fuel

 the back of the unit to l fue ery c he

ps by gravity down the chute t ds d a ightly e the pot.

Once the pellets drop from the chute they fall onto the top of the burning fuel bed. 

orced through the f d f elo d thro a serie nlet

holes in the bottom plate of the burn pot. The bottom plate of the burn pot is hinged. 

Periodically the con longer detected the

pot drops aw n its ge a mo n s ar

s by moving across the bott

processor and o s on edete ned sc le base the

the firing rate selected nce t leani ycle is mpleted

and automatically re-starts the bu pro .

mission rates were again d maller than 2.5 

and those larger than 2.5 microns. The results are presented in Table 43 and the 

ata recorded are pre d in e 44

ed self-cle

second wood pellet stove was similar in form and function to the first includ

ery hot air jet using a hot s

from cast t. It rpora

that require The ond u had a range of 14,6

60,200 Btu

about the

comparison

her w

test ru were nducte e range of 34,

38,400 Btu/hr. The major design differences being th elf-cl

(fire grate) and t al fo ustomizin the stov

operation to the f pr w pell

unit was designed to b e an

corn (kernels),

sunflower see t, the llets again ferre the

storage hopper in to the p of an interna l deliv hute. T

fuel dro hat en behin nd sl abov burn

Combustion air is f ire be rom b w, fe ugh s of i

trol stops the burn process and once the fire is no

bottom plate of the burn ay o hin nd a tor drive carper b

cleans any clinker om of the open burn pot. This is all 

controlled by the micro ccur a pr rmi hedu d on

type of fuel and . O he c ng c co the unit 

feeds more fuel rning cess

Particulate e etermined in two size categories, s

microns

gaseous emissions d sente Tabl .

Figure 13. Stove, overfed burner, enclosed self-clean burn pot/grate, electric ignition

44
Table 43 

Pellet stove, over fed burner, closed self-clean burn grate, electric ignition

Fine Particulate (PM 2.5)

Lbs /hr 4.3 4.6 4.8 

Btu /minute 567 620 633 

Kj /minute 598 653 668 

Oxygen % 13.25 13.25 13.25 

PM 2.5 sample mass mg 23.9 19.6 17.2 

Steady State 

Operation 

(8001 Btu/lb) 

Run time minutes 90 62 60 Average STDEV 

PM 2.5 mg/dscm 24 28 26 26 2 

PM mg/dscm @ 3% O2 71 85 77 78 7 

PM 2.5 mg/MJ 20 24 22 22 2 

PM 2.5 mg/kg 377 450 409 412 37 

Lbs /MMBtu 0.047 0.056 0.051 0.051 0.005 

Lb /Ton 0.75 0.90 0.82 0.82 0.07 

Gram particulate /hr 0.73 0.95 0.88 0.85 0.11 

 

Larger Particulate (>PM 2.5) Cyclone Catch

PM > 2.5 sample mass mg 10.1 8.1 4.7 Average STDEV 

PM > 2.5 mg/dscm 10 12 7 10 2 

PM > mg/dscm @ 3% O2 30 35 21 29 7 

PM > 2.5 mg/MJ 9 10 6 8 2 

PM > 2.5 mg/kg 159 186 112 152 38 

Lbs /MMBtu 0.020 0.023 0.014 0.019 0.005 

Lb /Ton 0.32 0.37 0.22 0.30 0.08 

Gram particulate /hr 0.31 0.39 0.24 0.31 0.08 

Table 44 

Pellet stove, over fed burner, closed self-clean burn grate, electric ignition

Measurement Range Average Avg. @ 3% Oxygen 

Temperature OF 377.6-395.4 386.4   

Oxygen % 13.77-16.40 14.76 ** ** 

CO2 % 4.35-7.02 5.91   

NOx ppm 28.3-45.7 38.6 131.4 

CO ppm 34.9-91.1 57.7 196.4 

SO2 ppm 0 0 0 

Efficiency % 68.1-76.6 73.5 ** ** 

45
 K. Wood pellet stove, horizontal unde en grate, with manual gel ignition

The third pellet stove (see Figur heavy steel plate and included 

a few cast iron components as well. It was designed for a fuel input range of 0.75 to 5.5 

poun r (6,000 – 44,000 Btu/hr). ing tes it wa low of

4.9 to a high of 5.2 pounds of fuel per ho he er grate) t can best

be described as a rear under-fed design with front side combustion air inlets 

(app an under fed burner type) t th

dow eldment where an a ra ed the pellets forward into 

the base of the burner pot (grate). The unit was t eq ed au start 

featu he use of a fire star gel e ge as spread out on top of the 

fuel bed in the burn pot and ignited with a match star

burn pot had a series of holes for combustion ai irst, pelle re fed b the fuel

auger into the bottom of the burner grate. e of the grate they forced

upward towards the open burner face where ll b As rning

proc eeds the ash produced then falls off u ge o burn

with unit had a fuel feed rate adjustm d an ircula lower 

adjustment on the control board. It also was equipped with an induced draft blower as 

were the other stoves

Part es were again dete ed o si catego , smaller than 2.5 

microns and those larger than 2.5 microns e re s ar esente Table and the

gase ded are presen in T e 46

r feed, op

e 14) was fabricated from

ds per hou Dur the t run s fired from a

ur. T burn pot ( on this uni

roximating . Pelle s from e integrated storage bin dropped 

n into the feeder body w uger t nsferr

no uipp with an tomatic

re and required t ting . Th l w

to t the unit. The front face of the 

r. F the ts a y

 Then by the d sign are

the pe ets are urned. the bu

ess proc the o ter ed f the er grate. As

all three stoves this ent an air c tion b

. 

iculate emission rat rmin in tw ze ries

. Th

ted

sult

abl

e pr

.

d in 45

ous emissions data recor

Figure 14. Pellet stove, side feed burner, open burner grate, and manual gel ignition 

46
Table 45 

Wood pellet stove, horizontal under feed burner, open grate, manual gel ignition

Fine Particulate (PM 2.5)

bs /hr 4.9 5.5 5.2 

tu /minute 653 728 696 

j /minute 689 768 734 

xygen % 13.25 13.25 13.25 

M 2.5 sample mass mg 33.7 38.4 35.7 

Steady State 

Operation 

(8001 Btu/lb) 

un time minutes 91 112 110 Average STDEV 

M 2.5 mg/dscm 33 30 29 31 2 

M mg/dscm @ 3% O2 77 71 67 72 5 

M 2.5 mg/MJ 24 22 21 23 2 

M 2.5 mg/kg

L

B

K

O

P

R

P

P

P

P 451 417 393 421 29 

Lbs /MMBtu 0.056 0.052 0.049 0.053 0.004 

Lb /Ton 0.90 0.83 0.79 0.84 0.06 

ram particulate /hr 1.00 1.03 0.93 0.99 0.05 

 

G

Larger Particulate (>PM 2.5) Cyclone Catch 

PM > 2.5 sample mass mg 6.1 7.5 5.1 Average STDEV 

PM > 2.5 mg/dscm 6 6 4 5 1 

PM > mg/dscm @ 3% O2 14 14 10 13 3 

PM > 2.5 mg/MJ 4 4 3 4 1 

PM > 2.5 mg/kg 82 81 56 73 15 

Lbs /MMBtu 0.010 0.010 0.007 0.009 0.002 

Lb /Ton 0.16 0.16 0.11 0.15 0.03 

Gram particulate /hr 0.18 0.20 0.13 0.17 0.04 

47
Table 46 

Wood pellet stove, horizontal under feed burner, open grate, manual gel ignition

Measurement Range Average Avg. @ 3% Oxygen 

Temperature OF 410.9-424.1 419.7   

Oxygen % 11.69-14.43 13.23 ** ** 

CO2 % 6.22-8.84 7.36   

5 38.8 

CO ppm 09

SO2 ppm 0-15 4 10.9 

Efficiency 5.9 ** ** 

+ Three readings were off scale (>500 ppm CO), taken as 500 ppm in average.

NOx ppm 34.8-44. 105.7 

53.5-500+ 2 569.5 

% 71.4-78.2 7

48
VI. Conclusions 

T

e d in New tate. The resu te gaseou l as

p d gra rmination of fine particulate emissions for a broad 

c of oil, gas llet emissions including liquid fuels of various sulfur 

c . The oil-fired s ults will be reviewed first, followed by those for gasfired heating appliances and then wood-fired pellet stoves. Then a comp of results

between the different fuel options will be pres f the equip ested was

m red and avail stallation in the United States. The ination of 

fine particulates was based on a dilution tunnel measurement following a conditional test 

protocol developed by the US-EPA, Conditional Test Method 39 (CTM-039). 

. Results for Oil-fired Heating Appliances 

The gaseous measurements of O2, CO2, CO, NOx and SO2 are presented in the previous 

chapter of this report for each test series. The results are basically as expected and as 

reported in prior studies on emissions. Based on excess air levels and ultimate analysis of 

the fuel’s chemical composition the emission results are as expected and fall within the 

range of emission factors contained in the US-EPA AP 42, Emission Factors Volume I, 

Fifth Edition. One area of the work that does expand on prior knowledge is the 

documentation of gaseous emissions for heating systems fired with biodiesel. Since were 

no unexpected findings the bulk of this report discussion will be centered on the 

emissions of fine particulates, or PM 2.5. 

The results for fine particulate (PM 2.5) indicate a very strong linear relationship between 

the masses of fine particulate for the different fuel oils as a function of the sulfur content 

of the fuel in question. This is illustrated by the plot contained in Figure 15 which clearly 

illustrates the linear relationship between the measured mass of fine particulate per unit 

of energy expressed as mg/MJ versus the different sulfur contents of four different 

heating fuels when used in the conventional cast iron boiler equipped with a flame 

retention head burner. The fuels included a typical No. 2 fuel oil with sulfur below 0.5 

percent (1520 average ppm S), a No. 2 fuel oil with very high sulfur content (5780-ppm

S), low sulfur heating oil (322-ppm S) and an ultra low sulfur diesel fuel (11-ppm S). The

bar chart in Figure 16 is a summary of results for three fuels (No. 2, LS and ULS) again 

when fired in the conventional cast iron boiler with a flame retention head burner. Three 

different emission rate units with each bar labeled with the value given to two significant 

figures. Three additional heating system types were also tested with normal heating fuel, 

low sulfur and ultralow sulfur fuel. These included an oil-fired warm air furnace of 

conventional design, a high efficiency condensing warm air furnace, a condensing 

hydronic boiler and the conventional hydronic boiler as discussed above. The linearity in 

the results was observed with all of the different oil-fired equipment types as shown in 

Figure 17. In this plot only the three fuels were included which explains the difference in

the formula for the trend line and R2

 factor (the coefficient of determination which is an

indicator of goodness of the fit) of the linear regression analysis. In all four cases the rsquared for the linear regression was 0.99 or better. 

his project has provided a compilation of emission data for residential heating

quipment use York S lts upda s emissions as wel

rovide a detaile vimetric dete

omparison and wood pe

ontents ystems res

arison

ented. All o ment t

anufactu able for in determ

A

49
Figure 15. Cast iron boiler, PM 2.5 as a function of sulfur content 

 

0

0 1000 2000 3000 4000 5000 6000 7000

Sulfur ppm

Cast Iron Boiler, Flam

0.5

PM 2.5 mg/

MJ

e Retention Head Burner

With Three Distillate Fuels, Sulfur Range 11-1520 ppm

Cast Iron Boiler, Flame Retention Head Burner

With Four Distillate Fuels, Sulfur Range 11-5780 ppm

4.5

5

y = 0.0008x

R2

 = 0.9978

1.5

2

2.5

3

3.5

4

1

 

Figure 16. Cast iron boiler PM 2.5 mg/MJ, m

0.025 1.18 0.49 0.092

22

1.32 1.7

60

4.7

0

10

20

30

40

50

60

70

mg/MJ mg/kg mg/dscm @3% O2

ULS 11-ppm S LS 450-ppm S No. 2 1520-ppm S

g/kg, mg/dscm for three fuels

50
Figure 17. PM 2.5 for conventional and condensing, boilers and furnaces 

B. Discussion of Biodiesel Blends 

As discussed in Section VI, F, the results obtained while testing with a soy biodiesel were 

y = 0.0009x

R2

 = 0.9892

y = 0.0014x

R2 = 0.9907

y = 0.0013x

R2

 = 0.9961

0

0.5

1

1.5

2

0 500 1000 1500 2000 2500

PM 2.5 mg/MJ

Boiler

Furnace

Cond. Boiler

Cond. Furnace

Linear (Boiler)

Linear (Furnace)

Linear (Cond. Boiler)

Linear (Cond. Furnace)

Conventional and Condensing Oil Fired Heating Appliances

With Middle Distillate Fuels, Sulfur Range 11-1520 ppm 

y = 0.0013x

R2

 = 0.9999

2.5

3

Sulfur ppm

quite unexpected. The first test was with biodiesel fired into a condensing oil-fired 

hydronic boiler. The result was a fine particulate emission of 1.7 mg/MJ that was only 

slight lower then the level found in the same boiler, which was 2.5 mg/MJ when fired 

with No. 2 fuel with a typical sulfur content of 1900-ppm sulfur. The uniqueness of the 

condensing oil-fired boiler which had been used in a prior field demonstration caused

concern that either the condensing mode might be exhibiting an unknown phenomenon or 

that the nature of the biofuel was so radically different as to cause a major difference in

the particulate emissions even though it was very low in sulfur content. In an attempt to 

resolve this, a conventional oil-fired boiler was tested with the same fuel. The result was 

an emission rate of 0.3 mg/MJ, still higher than one would expect based on a fuel that is

supposed to be nearly sulfur free. This level is about 60 percent of the average value 

found when using LS (500-ppm S) fuel as determined during this project equivalent to a

fuel with approximately 300-ppm sulfur. Based on the measurable levels of sulfur

dioxide and prior fuel analysis that found sulfur content in soy based biodiesel at a level 

of 340-ppm the result from the conventional boiler seems reasonable. However the level 

in the condensing boiler is still about five times greater. It would appear that there is 

something unusual occurring with the condensing boiler. Whether this was an artifact 

from prior use in the field and possible particulates from the boiler being washed up in

the flue gas stream or some other particulate generation phenomenon is unknown.

51
52

0.9

0

Unfortunately this was the last oil-fired boiler tested during the project. Limited funds 

remained for completing the reporting and information dissemination tasks and the 

budget would not allow for any additional tests to further investigate this question. 

C. Results for Gas-fired Heating Appliances 

Again, the gaseous measurements of O2, CO2, CO, NOx and SO2 are presented in the 

previous chapter of this report and the results are basically as expected and reported in 

prior studies on emissions. Based on excess air levels and ultimate analysis of the fuel’s

composition, the emission results are as expected and fall within the range provided for

emission factors contained in the US-EPA AP 42, Emission Factors Volume I, Fifth

Edition. Since there were no unexpected findings, the bulk of this discussion will be 

centered on the emissions of fine particulates, or PM 2.5. 

PM 2.5 Emission Factors for Several Natural Gas Fired Appliance

1.96

1.5

2

1

Figure 18. PM 2.5 emission factors for gas furnace, boiler and condensing boiler 

Three different gas-fired heating systems were tested. These included a conventional inshot induced draft warm air furnace, an atmospheric fired hydronic boiler and a high 

efficiency hydronic boiler. The particulate (PM 2.5) measured ranged from 0.011 to 

0.036 mg/MJ as shown in Figure 18. Tests included both steady state and cyclic 

operation. These were very low emission rates and to obtain these values sampling

0.011

0.63

0.043 0.016

0.06 0.036

0.13

0

.5

mg/MJ mg/kg Concentration at 3% O2

Furnace Boiler Condensing Boiler
occurred over long periods of operation. The actual sample size collected ranged form 2 – 

12 mg. Although there appears to be a difference in the level of emissions based on the 

heating system type the actual difference is well with in the range expected for gas-fired

equipment based on prior studies. In a 1993 study done by the California Institute of 

on tunnel designs, the value determined

as 0.046 mg per MJ +/- 0.017 for the residential heating units evaluated in the field 

stoves had measurable amounts 

of particulates sized above the 2.5-micron size that defines fine particulates (less than 2.5 

microns). The fine particulate emissions ra 22 to 30 mg/MJ as indicated 

in Figure 19, also included in the graph are emissions expressed in milligrams per

kilogram mg/kg and emission concentration as mg per dry standard cubic meter 

(mg/dscm). Although “Stove I” had larger emissions than the other two they are still 

within the same order of magnitude relative to each other. In addition to the particulate 

emissions being so high it is important to note that these stoves had significant levels of 

carbon monoxide in their flue products and so special attention should be followed to

venting requirements to avoid human exposure as with any combustion system in a home. 

Carbon monoxide levels in the exhaust flue averaged between 200 and 600-ppm. 

Technology using one of the first original diluti

w

which closely matches the values obtained in the current study. 

D. Results for Wood Pellet Stoves Manufactured in the United States

Three pellet stoves were included in this study. Wood pellet properties vary greatly 

depending on the raw material source used in their manufacture. All three stoves were

fueled with wood pellets obtained in a single batch to provide for uniformity in the test 

fuel. Unlike the oil and gas fired systems the wood pellet

tes ranged from

Three Pellet Stoves Evaluated for PM 2.5 and PM > 2.5 Microns

100

200

300

400

500

600

Stove I ove J Stove K

PM Less than 2.5 Microns (PM 2.5) PM Greater than 2.5 Microns

St

Figure 19. Three stoves evaluated for PM 2.5 and PM > 2.5 Microns 

0

mg/MJ mg/kg mg/dscm@ 3% O2 mg/MJ mg/kg mg/dscm@ 3% O2

53
E. Comparison of Results for all Residential Heating Appliances 

A summary comparison of results averaged by fuel types is shown in Figure 20 for the 

equipment included in this study. This summarizes the basic conclusions of the study

with regard to fine particulate emissions. 

• Gas-fired equipment has the lowest current particulate emissions averaging 0.014 

h typical sulfur

Figur tions

milligram per mega-Joule (mg/MJ).

• Oil-fired units currently have emissions averaging 1.7 mg/MJ wit

levels and this is approximately 120 times greater when compared to those for 

gas-fired units; reductions of 71% can be accomplished by using low sulfur fuel 

oil (500 ppm limit). 

• In the near future when fuel oil will be required to meet Ultra Low Sulfur limits of 

15-ppm sulfur, the particulate emissions will be of the same order of magnitude as

those found for gas fired units. In parts of New York this may happen by 2011. 

• Wood pellet stoves have emissions averaging 25 mg/MJ and this is approximately 

15 times greater than those of oil-fired units or approximately 1800 times greater

than gas fired units. 

• Wood pellet stoves are considered to have the lowest level of all wood fueled

heating systems in the United States. 

Comparison of Average PM2.5 for Five Heating Fuel Types

for Hydronic Boilers and Warm Air Funaces

0.016 0.025 0.49

1.32

0.011 0.06 0.51

2.1

25

0

5

10

15

20

25

30

Gas ULS LS ASTM No. 2 Wood Pellet

PM 2.5 mg/MJ

Boiler Furnace

Note: Wood pellet stoves included

e 20. Comparison of average PM 2.5 emissions for five heating fuel op

54
VII. Recommendations 

This report has identified the emissions to be expected from a wide range of heating 

equipment based on liquid fuel options, utility supplied gas and wood pellet resources. 

The greater part of effort was placed on generating a database for the mass emission rate 

f fine particulates (PM 2.5) for the various fuel types studied when fired in residential 

applian

Dis s

Homeo

burning natural gas, heating oil, wood. Natural gas use results in very low levels of PM

2.5

ASTM

times h tfire h

approx

levels possible with either utility gas or ultra low sulfur oil fueled appliances. Wood

pel

and DO

good c e the lowest emitters of particulates when 

compared to other type of wood burning appliances. Wood pellet fuel is a renewable 

resource that absorbs carbon dioxide during the natural growth cycle. This is considered

to be a benefit in helping to mitigate global climate changes by effectively reducing the 

carbon dioxide emissions that otherwise would be attributed to the use of wood pellet 

fuel. Like wood, biodiesel is also a renewable fuel and also absorbs carbon dioxide in the 

growth cycle of the crop plants used to produce the raw materials for biodiesel 

production, for example soybean or other seed crops. Biodiesel can be blended with 

ASTM heating No. 2 or ultra low sulfur heating oil. In either case it would effectively 

reduce the emissions of carbon dioxide based on its renewable nature. The extent of the

carbon dioxide reduction would be proportional to the amounts of biodiesel used in the 

blends. 

To summarize, natural gas has low PM 2.5 emissions but moderate carbon dioxide 

emissions. Wood pellet fuel has much higher PM 2.5 emission levels (based on current 

technology) but effectively lower carbon dioxide emissions due the renewable nature of 

trees that absorb carbon dioxide as they grow. ASTM No. 2 fuel as currently used has 

higher emissions of PM 2.5 than natural gas, much lower PM 2.5 emissions than wood 

pellet fuel and higher levels of carbon dioxide emissions than both alternatives.

Transitioning the sulfur content of fuel oil to ultra low levels (less than 15 ppm) results in 

PM 2.5 emissions are on the same order of magnitude as natural gas but still emits higher

levels of carbon dioxide. Natural gas produces about 30 percent less carbon dioxide per

Btu when compared to ASTM No. 2 or ultra low sulfur heating oil. Blending of ultra low 

sulfur with biodiesel in the future is anticipated as a alternative fuel choice and the 

sulting fuel blend would have very low PM 2.5 emissions as well as low net carbon 

di s

report presents carbon dioxide data as it was measured but the analysis of the net carbon 

o

ces. 

cus ion:

wners currently have many choices to heat their homes. These choices include 

emissions but being a hydrocarbon fuel it emits substantial levels of carbon dioxide. 

No. 2 fuel oil fired heating appliances produce PM 2.5 levels that are about 130 

igher than natural gas and higher emission levels of carbon dioxide. Wood pelle

d eating appliances made in the Untied States produce PM 2.5 levels that are

imately 15 times higher than ASTM fuel oil and from about 590 to 1850 times the 

let heating fuel is often selected over other forms of wood fuel choices based on EPA 

E guidance. This guidance suggests that the use of wood pellet appliances is a

hoice because they are considered to b

re

oxide emissions when the renewable nature of the fuel is taken into accounted. Thi

55
dioxide reduction based on the use of renewable fuels is beyond the scope of the current 

roject

ess with regard to residential heating technology in New York State as well 

s the other New England and Mid-Atlantic States where a majority of home heating is 

l combustion technologies. 

p

The question of how to reduce PM 2.5 emissions in areas that currently do not meet the 

criteria for EPA attainment is complex and is not part of the scope of this project. This 

project does however provide important data that should be useful to the overall decisionmaking proc

a

based on fue

56
Appendix A: Examples of Fuel Analysis Results 

Liquid Fuels Performed by Outside Testing Laboratories

57
Utility Supplied Natural Gas Analysis

58
Utility Supplied Natural Gas Analysis

59
Wood Pellet Analysis Performed by Outside Testing Laboratory 

60
Appendix

< less than 

> greater than

~ approximately 

C carbon 

CO carbon monoxide 

CO2 carbon dioxide 

O oxygen 

O2 molecular oxygen 

H hydrogen 

S sulfur 

SO2 sulfur dioxide 

SO3 sulphur trioxide 

SO4 sulfate 

N nitrogen 

NH3 ammonia 

NO nitric oxide or nitrogen monoxide 

NO2 nitrogen dioxide 

NOx NO + NO2 

Pb lead 

Avg average 

AFUE Annual Fuel Utilization Efficiency (US DOE rating) 

ASHRAE American Society of Heating and Refrigeration and Airconditioning Engineers 

ASME American Society of Mechanical Engineers 

ASTM American Society for Testing and Materials 

ASTM International Current official designation of ASTM 

ASTM No. 2 petroleum middle distillate fuel oil used as a heating fuel 

ASTM No. D1 petroleum middle distillate diesel fuel (kerosene) used as a 

transportation fuel with less than 15-ppm sulfur content 

ASTM No. D2 petroleum middle distillate diesel fuel used as a transportation fuel 

with less than 15-ppm sulfur content 

BART best available retrofit technology 

Btu British thermal unit 

CANMET Canada Centre for Mineral and Energy Technology, CANMET 

Energy Technology Centre 

CTM contingency test method (as in EPA CTM-039) 

dcp dry combustion products 

dcf dry cubic foot (combustion products) 

DOE United States Department of Energy 

DOE-EIA United States Department of Energy - Energy Information Agency 

dscm dry standard cubic meter 

EPA, US EPA United States Environmental Protection Agency 

ETV US EPA Environmental Technology Verification Program

ft foot

B: List of Abbreviations and Symbols

61
62

ph gallons per hour 

 and Development Authority 

tion products) 

ess than 500-ppm sulfur 

tu ish thermal unit 

nstitute 

SIP 

ft3

 cubic foot 

g

g gram 

μg microgram 

mg milligram 

kg kilogram 

hr hour 

μm micrometers (microns) 

m meter 

m3

 cubic meter 

NY New York 

NYS New York State 

NYSERDA New York State Energy Research

dscm dry standard cubic meters (combus

J Joule 

Lb pound 

LS low sulfur content fuel oil, l

kJ kilo-Joule 

MJ mega-Joule 

MMB million Brit

PFI Pellet Fuel I

ppm parts per million

PM 2.5 particulates less than 2.5 microns 

PM 10 particulates less than 10 microns 

state implimentation plan

TSP total suspended particulates