### Date: January 9

, 201 3

Subject: Kraft Pulping Liquor and Woody Biomass Methane (CH 4 

### ) and Nitrous Oxide

(N 2 

### O) Emission Factor Literature Review

EPA Contract No. EP

- W

- 11

- 054; Task Order No. 04

From: Katie Hanks

Corey Gooden

To: Mike Hannan

U.S. Environmental Protection Agency

Washington, DC 20460

I. Introduction

On November 16, 2012 the American Forest & Paper Association (AF&PA) and the

American Wood Council (A WC) petitioned the U.S. Environmental Protection Agency ( EPA ) to

r econsider and revise the m ethane (CH 4 

### ) and nitrous o xide (N 2 

### O) emission factors within 40

CFR Part 98, Subparts AA and C for combustion of spent pulping liquor and wood residuals

. These emission factors are used to calculate and report annual emissions from pulp mill recovery

furnaces and wood

- fired stationary combustion units under EPA’s mandatory greenhouse gas

reporting program (GHGRP). In support of their petition, AF&PA and AWC (the “petitioners”)

submitted a recent study performed by the National Council for Air and Stre am Improvement

(NCASI), Technical Bulletin 998, which contains new CH 4 

### and N 2 

### O emissions test data that

were not previously available to the GHGRP. Table 1 summarizes the existing GHGRP emission

factors and the revised emission factors recommended by the petitioners.

Table 1

– Comparison of Existing and R ecommended CH 4 

### and N 2 

### O Emission F actors

Greenhouse Gas Existing GHGRP

Emission Factor

(kg/MMBtu) Petitioners ’

Recommended Emission

Factor

(kg/MMBtu) Percent

Difference

(%)

Table AA

- 1

– Spent Pulping Liquor

Methane 0.030 0.0019 94

Nitrous Oxide 0.005 0.00042 92

Table C

- 2

– Solid Biomass

Methane 0.032 0.0049 85

Nitrous Oxide 0.0042 0.0019 55

The purpose of this memorandum is to review the basis for the current GHGRP spent

pulping liquor and wood residual combustion emission factors, integrate the new CH 4 

### and N 2 

### O

emissions test data provided in NCASI Technical Bulletin 998 with previously avail able2 

### emissions test data , and recommend possible regulatory amendments based on this work

. Section

II of this memorandum discusses the recovery furnace ( spent pulping liquor) emission factors.

Section III discusses the wood and wood residuals emission factors.

II. Recovery Furnace CH 4 

### and N 2 

### O Emission Factors

A. Recovery Furnace Literature Review

The CH 4 

### and N 2 

### O emission factors for kraft pulping liquor combustion in pulp mill

recovery furnaces are provided in Table AA

- 1 of 40 CFR part 98 S ubpart AA. Table AA

- 1 is

reproduced in Exhibit 1 below.

The CH 4 

### and N 2 

### O emission factors in Table AA

- 1 were based on the World Resources

Institute/World Business Council for Sustainable Development (WRI/WBCSD) protocol

developed by NCASI in 2005

. 1 

### Appendix A 1 contains a reproduction of the CH 4 

### and N 2 

### O

emission facto r summary table from the WRI/WB C S D p rotocol and Appendix A2 contains other

relevant pages from the WRI/WBCSD protocol. As shown in Appendix A 1

, four international

references were cited in the WRI/WB C S D protocol

. 2

, 3

, 4

, 5 

### The median of three of the emission

1 

### Calculation Tools for Estimating Greenhouse Gas Emissions from Pulp and Paper

Mills. Version 1.1. July 8, 2005. Prepared by the National Council for Air and Stream

Improvement for The Climate Cha nge Working Group of The International Council of

Forest and Paper Associations (ICFPA). http://www.wbcsd.org/web/projects/forestry/pulp

- and

paper

- tool

- guidance.pdf

2 

### Japan Paper Association (JPA). 2002. Various personal communications between JPA and Reid

Miner of NCASI . Tokyo: Japan Paper Association.

3 

### Swedish Environmental Protection Agency (Swedish EPA). 2004. Sweden’s national Exhibit 1

Table AA

– 1 to Subpart AA of Part 98

— Kraft Pulping Liq uor Emissions Factors for

Biomass

- Based CO 2 

### , CH 4 

### , and N 2 

### O

Wood furnish Biomass

- based emissions factors

(kg/mmBtu HHV)

CO 2 

### a CH 4 

### N 2 

### O

North American Softwood 94.4 0.030 0.005

North American Hardwood 93.7

Bagasse 95.5

Bamboo 93.7

Straw 95.1

a 

### Includes emissions from both the recovery furnace and pulp mill lime kiln.3 

### factors from the references formed the basis for the CH 4 

### emission factors recommended in the

WRI/WBCSD protocol (0.0025 kg/MMBtu) , and the median of two studies was the basis for the

recommended N 2 

### O emission factor (0.002 kg/MMBtu)

. The second reference (JPA 2002) did not

have an N 2 

### O factor and therefore could not be used in calculating the WRI/WBCSD

recommended median N 2 

### O emission factor. The fourth reference (EEA 2004) was mentioned in

the WRI/WBCSD protocol for comparison, but was not used in calculating the WRI/WBCSD

recommended median CH 4 

### and N 2 

### O emission factors

.

Given that the WRI/WBCSD CH 4 

### and N 2 

### O emission factors were based on only two or

three references which appeared to be uncertain based on the wide range in emissions from the

references, the highest of the referenced emission factors was selected for inclusion in the U.S.

EPA’s GHGRP Table AA

- 1 as a conservat ive measure . The highest values chosen from the

WRI/WBCSD protocol for Table AA

- 1 were 30 kilograms (kg) of CH 4 

### per terajoule (TJ) which

converts to 0.030 kg CH 4 

### per million British thermal units [MMBtu] and 5 kg N 2 

### O/TJ (0.005

kg/MMBtu)

. These emis sion factors originated from the Swedish EPA report. The 0.030 kg

CH 4 

### /MMBtu and 0.005 kg N 2 

### O/MMBtu emission factors were included in the original

greenhouse gas reporting rule ( 74 FR 16448, April 10 2009 ).

I n their November 2012 petition for rulemaking, the petitioners stated that the current

Table AA

- 1 emission factors (0.030 kg CH 4 

### /MMBtu and 0.005 kg N 2 

### O/MMBtu) are overly

conservative , especially in light of the new information submitted in NCASI Technical Bulletin

998. To investigate the petitioners’ conce rns, RTI searched for each of the references from the

WRI/WBCSD protocol to determine whether the references contained actual emissions test data

that could be compared to the new data in Technical Bulletin 998.

We were unable to locate any formal documentation of the JPA 2002 reference from the

WRI/WBCSD protocol

. We successfully located the remaining references, and found that only

Fortum 2001 contained actual emissions test data

. The Fortum study is discussed further in

Section II.B of this memorandum

.

The Swedish EPA 2004 report documents Sweden’s national GHG inventory but d oes

not include actual emissions test data

. The N 2 

### O emission factor for spent pulping liq uor was

confirmed in the reference documentation, but the CH 4 

### value of 30 kg/TJ was not

. It appears that

the same CH 4 

### emission factor for wood waste was used for spent pulping liquor

. Ap pendix B

provides the emission factor tables from the Swedish EPA report.

inventory report 2004

– Submitted under the United National Convention on Climate

Change . Stockholm: Swedish Environmental Protection Agency.

http://www.internat.naturvardsverket.se/documents/pollutants/climate/climate/fcccdata/N

IR.pdf (27 October 2004).

4 

### Fortum Power and Heat Oy (Fortum). 2001. Methane and nitrous oxide emissions in the

Finnish energy production . Fortum, Finland: Fortum Power and Heat Oy, Technology.

5 

### European Environment Agency (EEA). 2004. EMEP/CORINAIR Emission Inventory

Guidebook

- Third edition, September 2004 Update . Copenhagen: European Environment

Agency. http://reports.eea.eu.int/EMEPCORINAIR4/en (27 October 2004).4 

### The EEA 2004 reference is an update of the EMAP/CORINAIR Emissions inventory

guidebook

– Third edition . We did not locate the 2004 version of this document, but found that it

was replaced with a 2006 version (and a 2007 version was available)

. We were unable to locate

the 2004 emission factors using the newer document but we note that the EEA 2004 emission

factor range (as referenced in the WRI/WBCSD protocol) is nearly the same as the range of

emission factors provided in the 2006 Intergovernmental Panel on Climate Change (IPCC)

Guidelines ( IPC C 2006 )

. 6 

### The table from IPCC 2006 that contains the spent pulping liquor

emission factor s is reproduced in Appendix C1

. The IPCC 2006 emission factors for spent

pulping liquor are:

• 1 to 18 kg CH 4 

### /TJ (0.001 to 0.019 kg CH 4 

### /MMBtu) with a recommended default of 3 kg

CH 4 

### /TJ (0.0032 kg CH 4 

### /MMBtu), and

• 1 to 21 kg N 2 

### O /TJ (0.001 to 0.022 kg N 2 

### O /MMBtu) with a recommended default of 2 kg

N 2 

### O /TJ (0.002 kg N 2 

### O /MMBtu)

The IPCC 2006 report refers back to the 1996 IPCC Reference Manual as the source of the

default emission factors included in IPCC 2006 Table 2.3 for the manufacturing and construction

industries. However, as shown in Appendix C2, the 1996 Reference Manual does not include

emission factors for spent puling liquor combustion. We were unable to determine the basis for

the range of emission factors for spent pulping liquor in either EEA 2004 or IPCC 2006 . No

emissions test data were available in either document

.

B. Recovery Furnace Emissions Test Data

As mentioned pr eviously, the only reference we located with spent pulping liquor CH 4



### and N 2 

### O emissions test data was Fortum 2001. The Fortum report provides emission factors

derived fr om Fourier Transform Infrared Spectroscopy (FTIR) and n o n

- d ispersive infrared

(NDIR) testing of two recovery furnaces located at a pulp mill in Finland. One of the furnaces

was tested twice (once with spent liquor derived from softwood furnish and once with hardwood

furnish)

. Appendix D contains the Fortum study

. It appears that each test included only one

measurement (e.g., one test run)

. The CH 4 

### and N 2 

### O emissi ons averages from all three tests were

less than or equal to 1 mil ligram per megajoule (mg/MJ) (0.0011 kg/MMBtu).

The most commonly referenced compilations of pulp mill emission factors in the U.S

. include EPA’s AP

- 42 Section 10.2 on Chemical Wood Pulping (dated September 1990 ), 7 

### and

more recent NCASI Technical Bulletins 973 (February 2010) and 884 (August 200 4 ). 8

, 9

6 

### 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse

Gas Inventories. Intergovernmental Panel on Climate Change. Accessed at http://www.ipcc

nggip.iges.or.jp/public/2006gl/index.html

7 

### AP 42, Fifth Edition, Volume I Chapter 10: Wood Products Industry. Section 10.2

– Chemical

Wood Pulping. September 1990. Available at

http://www.epa.gov/ttn/chief/ap42/ch10/final/c10s02.pdf

8 

### NCASI. Compilation of ‘Air Toxic’ and Total Hydrocarbon Emissions Data for Pulp and Pap er

Mill Sources

– A Second Update. Technical Bulletin 973. February 2010.

9 

### NCASI. Compilation of Criteria Air Pollutant Emissions Data for Sources at Pulp and Paper

Mills Including Boilers, Technical Bulletin 884. August 2004.5 

### However, n o CH 4 

### or N 2 

### O emission factors are available in these documents for recovery furnace

spent pulping liquor combustion.

The recent NCASI Technical Bulletin 998 submitted by petitioners contains FTIR testing

of eight recovery furnaces using ASTM 6 348

- 03. 10 

### The U.S. EPA reference method for FTIR

emissions testing is Method 320 ( Vapor Phase Organic & Inorganic Emissions by Extractive

FTIR ) in Appendix A to 40 CFR Part 63. 11 

### The ASTM D6348

- 03 method NCASI used for the

CH 4 

### and N 2 

### O testing is incorporated by reference into 40 CFR 63.14(b) as an approved

alternative to Method 320 under two national emission standards for hazardous air pollutants

(NES H AP) affecting the forest products industry.

Technical Bulletin 998 documents emissi ons testing from three non

- direct contact

evaporator (NDCE) recovery furnaces and five direct contact evaporator (DCE) recovery

furnaces

. All of the recovery furnaces tested processed spent pulping liquor derived from kraft

pulping of hardwood or softwood feedstock. None of the furnaces processed any spent liquor

derived from bagasse, bamboo, or straw

. The kraft process is the most commonly used pulping

process in the U.S. No chemical recovery combu stion units (CRCU) found at sulfite and

semichemcial pulp mills were included in Technical Bulletin 998. Under the GHGRP, the Table

AA

- 1 CH 4 

### and N 2 

### O emissions factors for kraft pulping are used to estimate emissions for spent

pulping liquor in CRCU because no other information is available

.

Table 2 summarizes the results of the recovery furnace tests from Technical Bulletin 998.

The number of valid CH 4 

### and N 2 

### O test runs ranged from three to 10. Consistent with EPA

emission factor development procedures, values one half of the method detection limit (MDL)

were used in test averages when some of the test run results were non

- detect (ND) but others

were detected.

Although it might be expected that DCE recovery furnaces could have greater CH 4



### emissions than NDCE furnaces due to contact of the hot flue gases with incoming pulping liquor

in the DCE, the ranges of CH 4 

### and N 2 

### O emissions reported in Technical Bulletin 998 overlap for

the NDCE and DCE recovery furnaces. Therefore, it is reasonable for the GHGRP to continue to

make no distinction between DCE and NDCE recovery furnaces and to consider test data from

both types of furnaces together in a consolidated emission factor. Similarly, the ranges of the test

results overlapped for liquor derived from hardwood a nd softwood feedstocks, and across air

pollution control device types (wet bottom electrostatic precipitator [WBESP] and dry bottom

electrostatic precipitator [DBESP]).

10 

### ASTM D6348

- 03, Standard T est Method for Determination of Gaseous Compounds by

Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy.

11 

### EPA Method 320. Vapor Phase Organic & Inorganic Emissions by Extractive FTIR

. EPA’s

CFR

- promulgated air emissions measurement methods are available at

http://www.epa.gov/ttn/emc/promgate.html

### Table 2

. Summary of Recovery Furnaces T ested in Technical Bulletin 998

CH 4 , kg/MMBtu N 2 O , kg/MMBtu

ID Mill

type RF

type Spent

liquor

feedstock Other

fuels C ontrol No.

runs No.

ND

runs Min Max Average No.

runs No.

ND

runs Min Max Average

BRF5 kraft NDCE softwood DBESP 3 1 0.00039 0.001 0.00093 5 0 0.00062 0.0011 0.00082

DRF1 kraft NDCE softwood DBESP 8 7 0.000034 0.000047 0.000042 7 3 0.00012 0.00018 0.00015

ER F1 kraft NDCE softwood ESP 10 0 0.000065 0.0057 0.0031 10 7 0.000099 0.00065 0.00034

ARF3 kraft DCE softwood No. 6

oil DBESP 10 1 0.00008 0.00068 0.0002 9 0 0.00013 0.00043 0.00027

FR F1 kraft DCE unspecified WBESP 6 0 0.002 0.016 0.01 6 0 0.00044 0.00085 0.00065

FR F3 kraft DCE unspecified WBESP 9 0 0.00026 0.0021 0.0011 9 0 0.00034 0.00076 0.00049

GRF1 kraft DCE hardwood DBESP 6 5 0.0001 0.00015 0.00011 6 0 0.00012 0.00031 0.0002

GR F2 kraft DCE hardwood WBESP 5 0 0.0001 0.00016 0.00013 6 0 0.000092 0.00033 0.00019

The average was based on 1/2

- MDL values for

N D runs. Average: 0.00195 0.00039

min 0.000042 0.00015

max 0.01 0.00082

median 0.000565 0.000305

### Only one of the eight furnaces tested burned a small amount of fossil fuel during the

test s . Thus, the emission factors in Technical Bulletin 998 are representative of the biogenic CH 4



### and N 2 

### O emissions from recovery furnaces. Fossil fuel emissions from recovery furnaces are

estimated separately using equations and emission factors under Subpart C of the GHGRP.

The petitioners requested that EPA replace the current GHGRP Table AA

- 1 CH 4 

### an d

N 2 

### O emission factors with the average factors from Technical Bulletin 998 , specifically 0.0019

kg CH4/MMBtu and 0.00042 kg N 2 

### O /MMBtu

. [We note that the petitione r s’ recommen dation of

0.00042 kg N 2 

### O/MMBtu does not exactly match the average N 2 

### O emission factor of 0.00039 kg

N 2 

### O/MMBtu calculated in Table 2 , likely due to rounding of the average emission factors from

each test when they were reported in technical Bulletin 998.] Based up on the literature we

reviewed , Technical Bulletin 998 appears to be the most recent and comprehensive sour ce of

U.S. recovery furnace CH 4 

### and N 2 

### O emission factors available to date.

The Fortum 2001 test data (the only other actual emissions data we located) compare

fairly well with the data in NCASI Technical Bulletin 99 8. If the Fortum 2001 tests were

included with the NCASI Technical Bulletin 998 data, the resultant emission factors would be

0.0018 kg CH 4 

### /MMBtu and 0.00052 kg N 2 

### O/MMBtu as shown in Appendix E

. Inclusion of the

Fortum 2001 tests would have little effect of the petitioners’ suggested emission factors , but

continued application for the Fortum 2001 data for U.S. pulp mill recovery furnaces is

questionable in light of more recent test data obtained by NCASI from repeated m easurements of

recovery furnaces at U.S. mills. Table 3 compares the emission factors in the GHGRP to those

derived considering the Technical Bulletin 998 test data with and without the Fortum 2001 data.

T able 3. Emission F act ors for Spent Liquor Combustion in the GHGRP Table AA

- 1

C ompared to Emission Factors Derived from Available Emissions Test Data

Reference CH 4 

### , kg/MMB tu N 2 

### O, kg/MMB tu

GHGRP Table AA

- 1 0.03 0.005

Revised emission factors

suggested by petitioners (TB

998) 0.0019 0.00042 1



### Average of all available data

(TB 998 and Fortum 2001 as

shown in Appendix E) 0.0018 0.00052

1. Calculated as 0.0 0 039 in Table 2 of this memorandum, likely due to rounding.8 

### III. Wood and Wood Residuals Combustion CH 4 

### and N 2 

### O Emission Factors

A. Wood and Wood Residuals Literature Review

The CH 4 

### and N 2 

### O emission factors for combustion of solid biomass are provided in

GHGRP Table C

- 2. Table C

- 2 contains one row for “Biomass Fuels

- Solid (All fuel types listed

in Table C

- 1)

. ” Table C

- 1 of the GHGRP provides separate default higher heating values and

carbon dioxide (CO 2 

### ) emission factors for each type of solid biomass ( wood and wood residuals,

agricultural byproducts, peat, and solid byproduc ts)

.

The existing Table C

- 2 emissi on factors are base d on the Tier 1 emission factors for

wood and wood waste in IPCC 2006

. Appendix C1 of this memorandum contains the table from

IPCC 2006 (Table 2

- 3) that was the source of the GHGRP Table C

- 2 solid biomass emission

factors

. The IPCC Tier 1 e mission factors ranged from 10 to 100 kg CH 4 

### /TJ (0.011 to 0.11 kg

CH 4 

### /MMBtu) and 1.5 to 15 kg N 2 

### O/TJ (0.0016 to 0.016 kg N 2 

### O/MMBtu)

. The default emission

factors recommended by IPCC 2006 were 30 kg CH 4 

### /TJ (0.032 kg CH4/MMBtu) and 4 kg

N 2 

### O/TJ (0.0042 kg N2O/MMBtu) on a net caloric value basis.

RTI traced th e source of the IPCC 2006 Tier 1 emission factors back to the 1996

Reference Manual. Relevant excerpts and the reference list from the 1996 Reference Manual are

provided in Appendix C2 of this memorand um

. The 1996 Reference M anual emission factors for

many different fuels were based on , “ the CORINAIR90 database, the CORINAIR 1994 default

emission factors, the EDGAR Version 2.0 database, National Communications to the FCCC,

Berdowski, et al. (1993a and 1993b), Radian Corporation (1990) and US EPA (1995). ” RTI was

able to obtain three of these references ( National Communications to the FCCC , Radian

Corporation 1995

, and US EPA 1995 ), but did not find any actual emissions test data in the

references

. RTI w as unable to locate the other references from the IPCC Reference M anual

. The

IPCC Reference Manual states that “ additional research will need to be undertaken to further

improve the quality of the emission factors. ” The 1996 Reference Manual contained a Tier 2

emission factor for CH 4 

### of 15 kg CH 4 

### /TJ (0.016 kg CH 4 

### /MMBtu) in addition to the Tier 1

default factors adopted in the GHGRP. The Tier 2 emission factor was based on US EPA 1995

.

The 2005 WRI/W BCSD protocol recommended an emission factor of 12 kg CH 4 

### /TJ

(0.012 kg CH 4 

### /MMBtu) and 4 kg N2O/TJ (0.0042 kg CH 4 

### /MMBtu) based on the median of

emission factors from various studies, including the IPCC Tier 1 and Tier 2 emission factors

. Table 4 lists the biomass combustion CH 4 

### and N 2 

### O emission factor references from the

WRI /WBCSD protocol

.9 

### Table 4. References for the Biomass Emission Factors

Included in the WRI/WBCSD Protocol

Abbreviated reference

from WRI/WBCSD

protocol Full reference

EEA 2004 

### European Environment Agency (EEA). 2004. EMEP/CORINAIR

Emission inventory guidebook

- Third edition, September 2004 Update

. Copenhagen: European Environment Agency.

IPCC 1997 Intergovernmental Panel on Climate Change (IPCC). 1997c. Revised 1996

IPCC guidelines for national greenhouse gas inventories: Reference manual

(Vol. 3) . IPCC National Gr eenhouse Gas Inventory Program.

USEPA 2001 United States Environmental Protection Agency (USEPA). 2001. AP

- 42

emission factors for wood residue combustion in boilers

– Supplement G, July

2001 . Washi ngton, DC: United States E nvironmental Protection Agency.

Fortum 2001 Fortum Power and Heat Oy (Fortum). 2001. Methane and nitrous oxide

emissions in the Finnish energy production . Fortum, Finland: Fortum Power

and Heat Oy, Technology.

NCASI 1980 National Council for Air and Stream Improvement, Inc. (NCASI). 1980. A

study of wood residue fired power boiler total gaseous non

- methane organic

emissions in the Pacific Northwest . Air Quality Technical Bulletin No.109.

Research Triangle Park, NC: Nationa l Council for Air and Stream

Improvement, Inc.

NCASI 1985 National Council for Air and Stream Improvement, Inc. (NCASI). 1985.

Volatile organic carbon emissions from wood residue fired power boilers in

the Southeast . Technical Bulletin No.455. Research T riangle Park, NC:

National Council for Air and Stream Improvement, Inc.

JPA 2002 Japan Paper Association (JPA). 2002. Various personal communications

between JPA and Reid Miner of NCASI . Tokyo: Japan Paper Association.

AEA Tech. 2001 AEA Technology. 2001. UK greenhouse gas inventory 1990

- 1999: Annual

report for submission under the Framework Convention on Climate Change

. Oxfordshire, England: National E nvironmental Technology Centre.

Swedish EPA 2004 Swedish Environmental Protection Agency (Swedish EPA). 2004. Sweden’s

national inventory report 2004

– Submitted under the United National

Convention on Climate Change . Stockholm: Swedish E nvironmental

Protection Agency.



### The WRI/WCBSD protocol compared t he emission factors from the above references to

the emission factor range presented in EEA 2004. The EEA 2004 reference was not used in

calculating the WRI/WBCSD

- recommended median CH 4 

### and N 2 

### O emission factors for woody

biomass combustion

. Appendix A1 contains a reproduction of the CH 4 

### and N 2 

### O emission facto r

summary table from the WRI/WB C S D protocol and Appendix A2 contains other relevant pages

from the WRI/WBCSD protocol.

RTI was unable to locate any formal documentation of the JPA 2002 reference fro m the

WRI/WBCSD protocol. We successfully located the remaining references, and concluded that

only USEPA 2001, Fortum 2001, NCASI 1980, and NCASI 1985 contained actual emissions test

data

. These st udies are discussed further in Section III.B of this memor andum.10 

### Appendix F presents the table containing emission factors for wood from the AEA

Technology 2001 repo r t 12 

### and indicates that the AEA T echnology 2001 emission factors were

based on CORINAIR (1992) and IPCC (1997)

. Emission factors for “Wood

– Other Industry”

appear to be the source of the emission factors i ncluded in the WRI/WBCSD protocol ( al though

for CH 4 

### our conversions yielded an emission factor an order of magnitude lower than that

reported in the WRI/WBCSD protocol). Using 20 GJ/t of dry solids , we calculated emission

factors of 2.4 kg CH 4 

### /TJ and 3.5 kg N 2 

### O/TJ as opposed to the 24 kg CH 4 

### /TJ and 3.4 kg N 2 

### O /TJ

provided in the WRI/WBCSD protocol . Either we were unable to identify the exact emissions

factors used from the AEA Technology 2001 report, or possibly there was a decimal place typo

in the WRI/WBCSD CH 4 

### emission factor

. T he AEA Technology 2001 report did not contain any

actual emissions test data for woody biomass CH 4 

### and N 2 

### O.

The Swedish EPA 2004 report documents Sweden’s national GHG inventory and did not

include emissions testing

. Appendix B of this memo provides the emission factor tables from the

Swedish EPA report.

B. Wood and Wood Residuals Emissions Test Data

The only sources of actual emissions test data for CH 4 

### or N 2 

### O RTI was able to locate to

date include EPA’s AP

- 42 (USEPA 2001)

, Fortum 2001, NCASI 1980, NCASI 1985 and the

new test data (new testing and bo iler MACT data) used in NCASI Technical Bulletin 998

. Tables

6A and 6B in this section present the test results from each of these references.

The EPA’s AP

- 42 Chapter 1.6 contains a CH 4 

### emission factor based on four emissions

tests and an N 2 

### O emission factor based on two tests. The 1998 Industrial Combustion

Coordinated Rulemaking (ICCR) data base was the source of the four CH 4 

### tests. The N 2 

### O tests

were conducted prior to 1993 and referenced from a prior AP

- 42 report.

Fortum 2001 is a Finnish study that contains CH 4 

### and N 2 

### O emissions testing for six

biomass boilers

. Three of the boilers were tested with different fuel mixtures, for a total of nine

fuel mixture test s cenarios . The average of the results for the nine test s was reported in the

WRI/WBCSD protocol

. Review of Fortum 2001 reveals that only fi ve of the test s involved

woody biomass, and thre e of these tests were for boilers burning 50 percent or more of peat

. The

other four tests were for boilers burning peat or a combination of peat and sludge (which was not

described as industrial or municipal sludge so we interpreted this sludge to likely differ from

forest products wastewater treatment residuals)

. Peat is turf resulting from an accumulation of

partial ly decayed vegetation and is arguably different from woody biomass

. Table C

- 1 in the

GHGRP distinguishes peat from woo d and wood residuals. T he IPCC 2006 guidelines treat peat

as fossil carbon due to the long length of time it takes to replace harvested pe at. 13

12 

### http://uk

- air.defra.gov.uk/library/reports?report_id=8

13 

### IPCC 2006, p. G.3. http://www.ipcc

nggip.iges.or.jp/public/2006gl/pdf/0_Overview/V0_2_Glossary.pdf11 

### The Fortum 2001 study does not specify the number of measurements (test runs)

performed during each of the tests, so it is unclear if a three

- run test was performed as is

customary in the U.S. for stack testing. Table 5 below presents the results of the Fortum 2001

testing converted to kg/MM Btu. Poor combustion (e.g., high carbon monoxide emissions) was

noted for one of the bark boiler tests (BFB2)

. This test was excluded from the WRI/WBCSD

protocol

. The three tests where at least 50 percent woody biomass was burned are included in the

summary Table s 6A and 6B later in this section

. The BFB2 CH 4 

### test was also included in Table

6A because the results are the same order of magnitud e as two other tests noted in Technical

Bulletin 998 (also noted for po or combustion). It is reasonable to expect that similar poor

combustion could occur in some U.S. boilers (as evidenced by the two high CH 4 

### tests in the

boiler MACT d ata set documented in Technical Bulletin 998).

Table 5. Fortum 2001 Results from Emission Testing of B iomass B oilers in Finland

Unit Fuel CH 4 , kg/TJ CH 4 , kg/MMB tu N 2 O, kg/TJ N 2 O,

kg/MMB tu

Circulating Fluidised Bed Boilers

CFB1 peat 1 0.0011 < 2 0.0021

CFB1 peat, wood

(15%) 1 0.0011 4 0.0042

CFB2 peat, wood

(20%) 1 0.0011 3 0.0032

CFB3 peat < 1 0.0011 26 0.0274

CFB3 bark 1 0.0011 10 0.0105

CFB

Average 1 0.0011 9.0 0.0095

Bubbling Fluidised Bed Boilers

BFB1 peat 2 0.0021 < 1 0.0011

BFB2 bark * 72 0.0759 < 2 0.0021

BFB3 peat, bark

(50%) < 1 0.0011 < 2 0.0021

BFB3 peat, sludge 3 0.0032 < 2 0.0021

BFB

Average 19.5 0.017 3.2 0.0034

Overall

average 0.0097 0.0061

*Poor combustion conditions.



### As mentioned previously, the emission factors reported in the WRI/WBCSD protocol

from the two NCASI technical bulletins, TB 109 (NCASI 1980) and TB 455 (NCASI 1985) are

based on actual emissions testing of multiple boilers so the emission factors fr om the two

technical bulletins were included in Table 6A

. Technical B ulletin 109 contains volatile organic

carbon (VOC) emissions testing for four boilers, and Technical Bulletin 455 contains VOC

test ing for six boilers. RTI reviewed these technical bulletins and found CH 4 

### concentration data.

CH 4 

### is usually measured as part of the total organic compounds in a gas, but is not a VOC . CH 412 

### is sometimes reported separately if measured in conjunction with VOC. No flow rate data were

reported with the concentration measurements in the two technical bulletins so we were unable to

verify the emission factors reported in the WRI/WBCSD protocol or to extract boiler

- specific

CH 4 

### test results from the technical bulle tins. The emission factors provided in Table 6A are the

aggregated emission factors provided in the WRI/WBCSD protocol.

The 2012 NCASI Technical Bulletin 998 submitted by petitioners contains FTIR testing

of CH 4 

### and N 2 

### O emissions from five pulp mill boilers using ASTM 6348

- 03

. At least 90 percent

of the boiler heat input was from biomass during testing

. In addition, NCASI Technical Bulletin

998 provides results from a review of EPA Method 18 CH 4 

### test data contained in EPA’s boiler

maximum achievable c ontrol technology ( MACT ) data base for boilers firing more than 80

percent of heat input as biomass. P redominantly woody biomass boilers of various designs

(stoker, fluidized bed, fuel cell, dutch oven) firing wood, bark, or wastewater treatment (WWT)

slud ge were studied.

RTI downloaded the boiler MACT data base referenced by the petitioners 14 

### to determine

if additional CH 4 

### and N 2 

### O tests were available for major or area sources firin g predominantly

woody biomass. Consistent with Technical Bulletin 998, 19 methane tests (using EPA Method

18) for major source boilers wer e identified in the data base. The units of measure in the data

base were par ts per million rather than kg/MM Btu. A code

- breaker and more information (e.g.,

gas flow rates) would be n eeded to map the 19 tests in the data base to the 19 tests listed in

Technical Bulletin 998. We suspect that NCASI used the original boiler MACT test reports to

assemble the information in Technical Bulletin 998 as opposed to the informatio n directly from

the data base. No N 2 

### O tests were found in the data base (consistent with NCASI Technical

Bulletin 998 which did not tabulate N 2 

### O data from the MACT testing). No additional CH 4 

### or

N 2 

### O tests were identified in the data base for area sources. From this we can infer that all of the

available biomass CH 4 

### data from the boiler MACT emissions testing data base was used in

Technical Bulletin 998 (i.e., that tests were not chosen selectively). T he control devices used on

the biomass boilers included p articulate matter c ontrols (cyclone or multiclone, electrified filter

bed [EFB]

, electrostatic precipitator [ ESP ] , fabric filter) and other controls with unknown (or

unpredictable) effect on methane (dry sorbent in jection followed by an ESP or fabric filte r , spray

dryer and fabric filter, and wet scrubbers).

The new CH 4 

### and N 2 

### O emissions test da ta provided in Technical Bulletin 998 and test

data from other references are summarized in Table s 6A and 6B

. The data shown in these tables

represent measurements from combustion of various woody biomass fuels in different types of

boilers. P oor combustion condi tions were reported in three o f the boilers tested for CH 4



### . Combustion conditions can vary from boiler to boiler

. For example, it has been documen t ed that

poor combustion leads to higher CH 4 

### emissions, and fluidized bed combustors may operate

within a range of combustion temperatures that favors formation of N 2 

### O

. 15

, 16 

### In addition, o ther

14 

### May 30, 2012 Boiler MACT Draft Emissions and Survey Results Databases. Available at:

http://www.epa.gov/ttn/atw/boiler/boile rpg.html

15 

### Intergovernmental Panel on Climate Change (IPCC). 1997c. Revised 1996 IPCC guidelines for

national greenhouse gas inventories: Reference manual (Vol. 3) . IPCC National Greenhouse Gas

Inventory Program.13 

### wood

- fired combustion sources with diff ering conditions (e.g., direct wood fired dryers) may use

the GHGRP wood and wood residuals emission factors developed in this memo

. Therefore, it

seems reasonable to retain in Table 6A the tests where poor combustion was suspected as leading

to higher CH 4 

### emissions in ord er to account for variability and avoid underestimation of GHG

emissions from wood

- fired combustors . Similarly, given that some of the woody biomass boilers

that report under the GHGRP are fluidized bed boilers, it seems reasonable to retain the Fortum

dat a for fluidized bed boilers in the N 2 

### O data set in order to avoid underestimation of N 2 

### O

emissions.

16 

### Fortum Power and Heat Oy (Fortum). 2001. Methane and nitrous oxide emissions in the

Finnish energy production . Fortum, Finland: Fortum Power and Heat Oy, Technology.14 

### Table 6A

. Me thane Emissions Test Data from T echnical Bulletin 998 and Other References

Count Data Source Source ID Test Date APCD CH 4 , kg/MMB tu Min run Max run No. runs note

1 TB 998

- NCASI

Testing ABB2 7/8/2008 wet scrubber 0.0011 0.00044 0.0016 4 stoker

- bark

2 CCB4 12/2/2008 ESP 0.0031 0.0004 0.0077 6 stoker

- bark, no. 6 oil

3 DBB1 2/18/2009 ESP 0.00028 0.00017 0.00047 10 stoker

- bark

4 FBB1 3/23/2009 2 boilers with

common wet

scrubber 0.041 0.017 0.078 10 poor combustion; 2 wood

stokers

5 GCB3 6/10/2009 Wet scrubber 0.00068 0.00054 0.00099 6 stoker

- bark, no. 6 oil

6 TB 998

- MACT HCB1 7/15/2009 Not Reported 0.00012 0.00011 0.00012 3 [all ND] bark, resin wood

7 ICB1 7/14/2009 Not Reported 0.0018 0.0016 0.002 3 hog fuel, MSW, gas

8 JCB2 7/1/2009 Not Reported 0.0076 0.0037 0.01 3 bark, TDF, oil

9 KCB2 8/4/2009 Not Reported 0.00043 0.00029 0.00061 3 bark

10 LCB1 8/13/2009 Not Reported 0.00072 0.00037 0.00092 3 wood/bark

11 MCB3 8/6/2009 Not Reported 0.00032 0.00022 0.00048 3 wood waste

12 NCB1 8/6/2009 Not Reported 0.001 0.0005 0.0014 3 bark

13 OCB4 8/11/2009 Not Reported 0.00023 0.00015 0.00031 2 bark, oil, gas; 1 run omitted

(0.00371 kg/mmbtu)

14 PCB4 8/5/2009 Not Reported 0.00018 0.00016 0.00021 3 bark, WWT sludge, TDF

15 QCB8 7/29/2009 Not Reported 0.0007 0.00064 0.00076 3 WWT sludge, bark

16 RCB1 9/2/2009 Not Reported 0.0016 0.00046 0.0036 3 bark

17 SCB1 8/14/2009 Not Reported 0.0022 0.00078 0.0047 3 bark, cross ties, gas, WWT

sludge

18 TCB1 8/11/2009 Not Reported 0.0015 0.00053 0.0024 3 wood

19 UCB2 6/24/2009 Not Reported 0.0027 0.00075 0.005 3 wood/bark, WWT sludge,

OCC rejects, gas

20 VCB2 8/6/2009 Not Reported 0.0012 0.00055 0.0023 3 bark, WWT sludge, cross

ties, gas

21 WCB1 7/30/2009 Not Reported 0.0012 0.00093 0.0014 3 bark, OCC rejects, gas,

WWT sludge

22 XCB1 8/13/2009 Not Reported 0.0052 0.003 0.0056 3 bark

23 YCB1 8/6/2009 Not Reported 0.046 0.032 0.056 3 poor combustion; bark, gas

24 ZCB1 10/8/2009 Not Reported 0.0048 0.0034 0.0046 3 bark

25 AACB1 7/29/2009 Not Reported 0.0048 0.00091 0.011 3 wood/bark

26 ABCB1 7/23/2009 Not Reported 0.0007 0.00063 0.00084 3 bark/wood

27 ACCB1 7/29/2009 Not Reported 0.00051 0.00014 0.00096 3 bark15 Count Data Source Source ID Test Date APCD CH 4 , kg/MMB tu Min run Max run No. runs note

28 NCASI 1980 pre

- 1980 None 0.0086 Avg EF Pre

- 1980 stoker ahead of

control device

29 NCASI 1985 pre

- 1985 Wet Scrubber 0.0028 Avg EF Pre

- 1980 stoker after

scrubber

30 Fortum 2001 CFB3 pre

- 2001 None 1 0.0011 FB

- bark

31 BFB2 pre

- 2001 None 1 0.0759 FB

- bark; poor combustion

32 BFB3 pre

- 2001 None 1 0.0011 FB

- peat, bark (50%); ND

33 AP

- 42, Ch 1.6 B109 9/24/1996 Wet Scrubber 0.020 0.037 0.053 3 Bark/Wet Wood

34 B47 6/1/1995 Fabric Filter 0.0030 0.0055 0.0090 3 Wet Wood. B47 & B48 are

dual stacks on the same

boiler.

35 B48 6/1/1995 Fabric Filter 0.0052 0.00016 0.025 3 Wet Wood. B47 & B48 are

dual stacks on the same

boiler.

36 B49 12/22/1994 ESP 0.0091 0.010 0.032 3 Wet Wood

NCASI Min 0.00012

TB 998 Max 0.046

Average 0.0049

Stdev 0.011

Median 0.0012

All Min 0.00012

Max 0.076

Average 0.0072

Stdev 0.016

Median 0.0016

All but Min 0.00012

Fortum Max 0.046

Average 0.0055

Stdev 0.011

Median 0.0016

Current GHGRP Table C

- 2 Factor 0.032



### 1. The report stated that all tests were completed with no limestone feed.16 

### Table 6B

. N 2 

### O Emissions Test Data from T echnica l Bulletin 998 and Other Refere nces

Count Data Source Source ID Test Date APCD N 2 O,

kg/MMB tu Min run Max run No. runs note

1 TB 998

- NCASI

Testing ABB2 7/8/2008 wet scrubber 0.0027 0.0014 0.004 5 stoker

- bark

2 CCB4 12/2/2008 ESP 0.0015 0.0012 0.0019 6 stoker

- bark, no. 6 oil

3 DBB1 2/18/2009 ESP 0.0011 0.00062 0.0013 10 [2 ND] stoker

- bark

4 FBB1 3/23/2009 2 boilers with

common wet

scrubber 0.00073 0.00028 0.0023 10 [2 ND] poor combustion; 2

wood stokers

5 GCB3 6/10/2009 Wet scrubber 0.0034 0.002 0.0048 6 stoker

- bark, no. 6 oil

6 Fortum 2001 CFB3 pre

- 2001 None 1 0.0105 FB

- bark

7 BFB2 pre

- 2001 None 1 0.0021 FB

- b ark; ND

8 BFB3 pre

- 2001 None 1 0.0021 FB

- peat, bark (50%);

ND

9 AP

- 42, Ch 1.6 pre

- 1993 Not Reported 0.010 FBC

- Wet Wood

10 pre

- 1993 Not Reported 0.0020 Stoker

- Wet Wood

NCASI Min 0.00073

TB 998 Max 0.0034

Average 0.0019

Stdev 0.0011

Median 0.0015

All Min 0.00073

Max 0.011

Average 0.0036

Stdev 0.004

Median 0.0021

All but Min 0.00073

Fortum Max 0.010

Average 0.0031

Stdev 0.0032

Median 0.0020

Current GHGRP Table C

- 2 Factor 0.0042



### 1. The report stated that all tests were completed with no limestone feed.17 

### Based up on the literature reviewed , Technical Bulletin 998 appears to be the most recent

and comprehensive source of wood

- fired boiler CH 4 

### and N 2 

### O emission factors available to date.

The data presented in Technical Bulletin 998 could be used alone or in conjunction with older

emissions test data to add a row to the GHGRP Table C

- 2 with emission factors for wood and

wood residuals. Tab le 7 summarizes the current solid biomass emission factors in Table C

- 2, the

revised emission factors requested by petitioners based on NCASI TB 998 , and other alternatives

incorporating older emissions test data

. The current GHGRP Table C

- 2 factors are not limited to

woody biomass and apply for “Biomass Fuels

- Solid (All fuel types listed in table C

- 1).”

However, the test data presented in Tables 6A and 6B are based primarily on boilers firing wood

and wood residuals. The refore, EPA could add a row to Table C

- 2 for “wood and wood

residuals” similar to the current Table C

- 1, and leave the existing Table C

- 2 biomass factors for

other forms of solid biomass.

Table 7. Emission factors for Wood and Wood Residuals Derived from the Available Data

Reference CH 4 

### , kg/MMBtu N 2 

### O, kg/MMBtu

GHGRP (based on IPCC

2006) 0.032 0.0042

Revised emission factors

suggested by petitioners (TB

998) 0.0049 0.0019

Average o f all available data 0.0072 0.0036

Averag e of available data

without Fortum 200 1 0.0055 0.0031

IV. Summary and Conclusions

RTI performed a literature review to document the basis for the existing GHGRP CH 4



### and N 2 

### O emission factors in Subpart AA for spent pulping liquor and in Subpart C for solid

biomass fuels (specifically wood and wood r esiduals). The purpose of the literature review was

to locate additional emission testing results that could be compared to new information (NCASI

T echnical Bulletin 998) supplied through a November 2012 petition for rulemaking. RTI found

that few of the previously referenced sources of CH 4 

### and N 2 

### O emission factors were based on

actual emission test data , and that the few references containing test data were dated and/or based

on emissions sources outside of the U.S

. The information provided in NCASI Technical Bulletin

998 appears to be the more rob ust than previous references due to the number and variety of U.S.

emission sources for which recent test data are provided

. The EPA can use the summary

information presented in this memorandum to consider w hether to adopt the emission factors

suggested by the petitioners based on NCASI Technical Bulletin 998 or to combine the new data

with previously available emission test data in order to revise the CH 4 

### and N 2 

### O emission factors

in Table AA

- 1 and C

- 2.

### Appendix A

Excerpts from the WRI/WBCSD Protocol, Calculation Tools for Estimating Greenhouse

Gas Emissions from Pulp and Paper Mills

, Version 1.1, July 8, 2005

Appendix A1: Biomass Combustion CH 4 

### and N 2 

### O Emission Facto r Summary Table from the

WRI/WB C S D Protocol

Appendix A2: Addi tional Excerpts from the WRI/WB C S D Protocol

Available at:

http://www.wbcsd.org/web/projects/forestry/pulp

- and

- paper

- tool

- guidance.pdf

### Appendix B

Emission Factor Tables from Swedish EPA 2004

Available at:

http://s3.amazonaws.com/zanran_storage/www.lansstyrelsen.se/ContentPages/70817864.pdf

### Appendix C

IPCC Emission Factor Documentation

Appendix C1: Portion of 2006 IPCC Guidance Document Table 2. 3, Default Emission Factors

for Stationary Combustion in the Manufacturing Industries and Construction

. Available at: http://www.ipcc

nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_2_Ch2_Stationary_Combu stion.pdf

Appendix C2: Excerpts from the Revised 1996 IPCC Guidelines for National Greenhouse Gas

Inventories Reference Manual (Volume 3), Chapter 1

– Energy.

Available at: http://www .ipcc

- nggip.iges.or.jp/public/gl/invs6a.html

### Appendix D

Fortum 2001

-

Methane and nitrous oxide emissions in the Finnish energy production

.

Available at :

http://energia.fi/sites/default/files/non

- co2

- raportti.pdf

### Appendix E

Emission Factor Data from Fortum 2001 Combined with

NCASI Technical Bulletin 998 Data

### Appendix E. Emission Factor Data from Fortum 2001 Combined with NCASI Technical Bulletin 998 Data

(The Fortum 2001 data are shaded.)

CH 4 , kg/MMBtu N 2 O , kg/MMBtu

ID Mill

type RF

type Spent

liquor

feedstock Other

fuels C ontrol No.

runs No.

ND

runs Min Max Average No.

runs No.

ND

runs Min Max Average

BRF5 kraft NDCE softwood DBESP 3 1 0.00039 0.001 0.00093 5 0 0.00062 0.0011 0.00082

DRF1 kraft NDCE softwood DBESP 8 7 0.000034 0.000047 0.000042 7 3 0.00012 0.00018 0.00015

ERF1 kraft NDCE softwood ESP 10 0 0.000065 0.0057 0.0031 10 7 0.000099 0.00065 0.00034

ARF3 kraft DCE softwood No. 6

oil DBESP 10 1 0.00008 0.00068 0.0002 9 0 0.00013 0.00043 0.00027

FRF1 kraft DCE unspecified WBESP 6 0 0.002 0.016 0.01 6 0 0.00044 0.00085 0.00065

FRF3 kraft DCE unspecified WBESP 9 0 0.00026 0.0021 0.0011 9 0 0.00034 0.00076 0.00049

GRF1 kraft DCE hardwood DBESP 6 5 0.0001 0.00015 0.00011 6 0 0.00012 0.00031 0.0002

GRF2 kraft DCE hardwood WBESP 5 0 0.0001 0.00016 0.00013 6 0 0.000092 0.00033 0.00019

RB1 unspecified softwood unspecified unspecified

RB1 unspecified hardwood unspecified 0.0011 unspecified 0.0011

RB2 unspecified softwood unspecified 0.0011 unspecified 0.0011

The average was based on 1/2

- MDL values for

ND runs. Average: 0.0018 0.00052

min 0.000042 0.00015

max 0.01 0.00105

median 0.00099 0.00042

### Appendix F

Wood Emission Factors from AEA Technology 2001

Available at: http://uk

- air.defra.gov.uk/library/reports?report_id=8