## A Demonstration of Fat and Grease as an Industrial Boiler Fuel

Principal Investigator: Dr. Thomas T. Adams, P.E., Public Service Associate UGA Engineering Outreach Service (EOS)

Coinvestigators: Jim Walsh, GA Tech EDI Mike Brown, GA Tech EDI Dr. John Goodrum, UGA Bio. & Ag. Eng. Dr. Jackie Sellers, UGA Bio. & Ag. Eng.

Dr. Keshav Das, UGA Bio. & Ag. Eng.

Project Administrator: Dr. E. Dale Threadgill, Director Faculty of Engineering The University of Georgia

Project/Report Manager: Robert J. Synk, P.E., Project Management Resources, Inc.

Project/Report Contributors: Erin Callaghan, Public Service Representative, UGA, EOS Bryan Graffagnini, Res earch Engineer, UGA EOS Javier Sayago, Chemist, UGA EOS

The University of Georgia Engineering Outreach Service Driftmier Engineering Center Athens, GA 30606-4435

June 30, 2002

Jointly Funded by: Poultry Protein & Fat Council of the U.S. Poultry & Egg Association Fats and Proteins Research Foundation, Inc. The University of Georgia

# A Demonstration of Fat and Grease as Industrial Boiler Fuel

EXECUTIVE SUMMARY
The University of Georgia (UGA) Engineering Outreach Service (EOS) used fats and grease (chicken fat, yellow grease, choice white grease, and beef tallow) as industrial boiler fuels in the 100,000 lb./hr. No. 2 boiler at the UGA steam plant during January and February 2002. The project was funded by the Fats and Proteins Research Foundation, Inc. and the Poultry Protein & Fat Council of the U.S. Poultry & Egg Association. The objectives of the project were to publicly dem onstrate the use of biofuel for industrial steam production and to exam ine the procedures necessary for its use.

F uel No. of T e s t s N a tu r a l Ga s 9 Choi c e W h i t e G r eas e 10 Choi c e W h i t e G r eas e - F uel O i l B l end 12 T a llo w 13 T a llo w F u e l - O il B l e n d 15 Y e l l o w G r eas e - F uel O i l B l end 19 Y e llo w G r e a s e 21 No. 2 F uel O i l 22 Chi c k en F a t - F uel O i l B l end 23 Chi c k en F a t 29 To ta l 173

T e s t s w e r ec o nduc t e d J a n. 28 t h r u Ma r

. 15, 2002. 

### C o m bus t i on T e s t P r ogr a m S u m m a r y



## Biofuels, either singly or blended with No. 2 fuel oil, are technically and

econom ically viable alternatives to No. 2 fuel oil. Biofuels are user friendly and less hazardous than petroleum fuels. The addition of biofuel com bustion capability is sim p le and inexpensive. It is not necessary to replace or com p rom i se the operation of existing fossil fuel system s.
Industrial boiler operators can use these results to econom ically justify the use of biofuels and to support air em issions perm it subm ittals. Even lower em issions levels

m a y be obtained from boilers em ploying advanced com bustion system s.

Summary of Results:

1. Laboratory analyses showed that the fats and greases tested have high heating value, low ash, negligible sulfur, low m o isture, and other physical and chem ical properties conducive to their use as boiler fuel. Heating values for the biofuel blends tested are within 95% of the heating value of No. 2 fuel oil.

i

## 2. The 100,000 lb./hr. No. 2 boiler at the UGA steam plant was retrofitted to burn biofuels for approxim a tely $31,000, including the cost to add flue gas recirculation (FGR). This am ount does not include any expense for the construction of f

u el storage f acilities, which were not required f o r the dem onstration program . The biofuel heat exchanger was obtained without cost to the project. It was not necessary to replace or m odify the boiler fuel train or nozzle for these tests.

3. The tests dem onstrated that the biofue ls burn cleanly, readily, without odor and without dam a ge to boiler equipm ent.

4. During this test program , biofuels produced steam within 3.8% to 5.3% of the efficiency of No. 2 fuel oil. Biofuels blended with No. 2 fuel oil were m o re efficient than unblended biofuels, and can actually produce steam with m o re efficiency than No. 2 fuel oil. Throughout the tests part load efficiency was greater than m a xim u m load efficiency, and steam production with FGR was m o re efficient than without FGR.

5. Biofuels are clean burning. They generally produce fewer com bustion em issions than No. 2 fuel oil.

6. Flue gas recirculation is an effective way to reduce NO x 

## em issions for both fossil and biofuels.

Impact of the Research Results relative to the requirements for Boiler No. 2 in the UGA Part 70 Operating (air emissions) Permit (“the Permit”):

1. The Perm it prohibits the burning of any fuel whose sulfur content exceeds 1.3% (para. 3.2.1). The m a xim u m sulfur content of any biofuel tested was 0.007%, and 0.13% for any biofuel blended with No. 2 fuel.

2. The Perm it lim its particulate m a tter em issions to 0.417 lb/mm B tu (para. 3.4.1). The m a xim u m total particulate (non-condensible and condensible) em ission rate of any biofuel was 0.083 lb/mm B tu.

3. The Perm it lim its visible em issions to 40% opacity (para. 3.4.9). Sm okestack opacity ranged between 0% and 11% during the biofuel tests.

Impact of the Research Results relative to the GA Rules for Air Quality Control (the “Rules”):

1. The Rules (Sections (2)(d)2 & 3) lim it particulate em issions from all fuel-burning equipm ent, of any size, to 0.10 lb/mm B tu and opacity to 20%. The m a xim u m total particulate (non-condensible and condensible) em ission rate of any biofuel was 0.083 lb/mm B tu. Sm okestack opacity ranged between 0% and 11% during the biofuel tests.

ii

## 2. The Rules (Section (2)(d)4) lim it NO x 

## em issions to 0.3 lb/mm B tu from fuel oil burning equipm ent, of any size, in an attainm e nt area. The m a xim u m NO x 

## em ission rate of any biofuel tested was 0.23 lb/mm B tu.

Contents

Introduction Section 1 Analysis of Fats and Greases Section 2 Test Facility Description Section 3 Com bustion Dem onstration Section 4 Em issions Testing Section 5 Conclusions Section 6 R e f e r e n c e s S e c t i o n 7 Appendices Section 8

Acknow ledgements
This research project was jointly funded by Poultry Protein & Fat Council of the U.S. Poultry & Egg Association, the Fats and Protein Research Foundation, Inc., and The University of Georgia

The University of Georgia (UGA) Engin eering Outreach Service (EOS) gratefully acknowledges the support of:

• The test team : Erin Callaghan, Bryan Graffagnini, and Javier Sayago,

• UGA steam plant personnel, in particular: John Benca, Jim Olbrych, Danny Langston, Jerry Bray, Dwight Epps and Doug Pittard,

• UGA Environm ental, Health & Safety personnel, in particular, Mike Stover,

• UGA faculty, in particular: Dr. John Goodrum , Dr. Jackie Sellers, and Dr. Keshav Das,

• UGA Physical Plant Plum bing, Sheet Me tal, Electrical and W e lding Shops,

• Am erican Proteins, Inc., especially: Roger Sm ith, Kevin Custer, and Gary Bottom l ey,

• Griffin Industries: Shannon Behim e r and Dana Hand,

• The GA Dept. of Natural Resources: Don Holder and Susan Jenkins, and

• The Georgia Environm ental Partnership.

iii

## 2. ANALYSIS OF FATS AND GREASE

2.1. Introduction

Laboratory analyses of the fats and grease (biofuel oils) established their

comm e rcial specifications relative to standard m a rket product designations. The physical properties of the biofuel oils were used to design the test facility at the UGA central steam plant.

2.2. Sam p ling Procedures

During the com bustion test program , the test team random ly collected three 500-

m l sam p les of each fuel, one each at the beginning, m i ddle and end of each test series. A total of (33) fuel sam p les were obtained: six (6) sam p les each of chicken fat and yellow grease; and three (3) sam p les each of choice white grease, tallow, No. 2 fuel oil and the blends of chicken fat, yellow grease, choice white grease and tallow. (All blends consisted of 33% fat or grease and 67% No. 2 fuel oil.) The team also collected four (4) sam p les of various solid combustion byproduct residues from inside the boiler.

The project procedures m a intained sam p le chain of custody from initial sam p ling through analysis.

After initial cooling, the test sam p les were secured in refrigerated storage (4 deg. C.) while at UGA. The test sam p les were divided into sm aller sam p les for analyses by the UGA laboratories and by comm e rcial laboratories. The sam p les analyzed by comm e rcial laboratories were overnight shipped in “cold packs”.

Fig. 3. Fuel sam p ling during test

2 - 1

## 2.3. Fat and Grease Properties

Te s t C h ic k e n Fa t Ye l l o w G r eas e Ch oi c e W h i t e G r eas e Ta llo w

C0 8: 0 < 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C1 0: 0 < 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C1 1: 0 < 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C1 2: 0 < 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C1 4: 0 0

. 5 7 % 0. 70 % 1

. 5 7 % 2. 73 % C1 4: 1 0

. 2 6 % 0. 14 % 0

. 3 6 % 0. 50 % C1 5: 0 < 0. 10 % 0

. 1 1 % 0. 26 % 0

. 4 3 % C1 5: 1 < 0. 10 % < 0. 10 % < 0. 10 % 0

. 1 6 % C 1 6 : 0 2 2. 76 % 1 4. 26 % 2 2. 04 % 2 2. 99 % C1 6. 1 8

. 3 7 % 1. 43 % 5

. 0 3 % 2. 86 % C1 6. 2 < 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C1 6. 3 < 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C1 6. 4 < 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C1 7: 0 0

. 1 1 % 0. 33 % 0

. 6 3 % 1. 35 % C1 7: 1 0

. 1 2 % 0. 23 % 0

. 4 3 % 0. 75 % C1 8. 0 5

. 3 6 % 8. 23 % 9

. 9 5 % 19

. 4 4% C 1 8

. 1 4 2. 07 % 4 3. 34 % 4 2. 45 % 4 1. 60 % C 1 8

. 2 1 7. 14 % 2 6. 25 % 1 3. 17 % 3

. 9 1% C1 8. 3 1

. 0 7 % 2. 51 % 0

. 9 7 % 0. 49 % C1 8. 4 0

. 2 2 % 0. 47 % 0

. 2 9 % 0. 36 % C2 0. 0 < 0

. 1 0 % 0. 33 % 0

. 1 4 % 0. 14 % C2 0. 1 0. 45 % 0

. 4 8 % 0. 56 % 0. 33 % C2 0. 2 0. 20 % < 0. 10 % 0

. 1 9 % < 0

. 1 0 % C2 0. 3 0. 19 % < 0. 10 % 0

. 1 2 % < 0

. 1 0 % C2 0. 4 0. 45 % < 0. 10 % 0

. 3 4 % < 0

. 1 0 % C2 0. 5 < 0

. 1 0 % < 0

. 1 0 % 0. 11 % < 0. 10 % C2 1: 5 <0 .1 0 % <0 .1 0 % <0 .1 0 % <0 .1 0 % C2 2: 0 < 0

. 1 0 % 3. 50 % < 0. 10 % < 0. 10 % C2 2: 1 <0 .1 0 % <0 .1 0 % <0 .1 0 % <0 .1 0 % C2 2: 2 <0 .1 0 % <0 .1 0 % <0 .1 0 % <0 .1 0 % C2 2: 3 <0 .1 0 % <0 .1 0 % <0 .1 0 % <0 .1 0 % C2 2: 4 0. 10 % < 0. 10 % < 0. 10 % < 0. 10 % C2 2: 5 < 0

. 1 0 % < 0

. 1 0 % 0. 14 % < 0. 10 % C2 2: 6 < 0

. 1 0 % < 0

. 1 0 % 0. 22 % < 0. 10 % C2 4: 0 < 0

. 1 0 % 0. 12 % < 0. 10 % < 0. 10 % C2 4: 1 <0 .1 0 % <0 .1 0 % <0 .1 0 % <0 .1 0 %
unk no w n
c o m p on en t s 0. 56 % 0

. 7 2 % 1. 03 % 1

. 9 6 %

Mo i s tu re &

V o l a tile s 0. 12 % 0

. 3 8 % 0. 24 % 0

. 1 7 %

In s o lu b l e Im p u r i tie s 0. 08 % 0

. 0 6 % 0. 29 % 0

. 1 2 %

Un s a pon i f i a bl e M a tte r 0. 51 % 0

. 4 2 % 0. 73 % 0

. 3 0 % Ta bl e 1 , F a t an d G r ea se P r o p e rt i e s 1

1) W o o d s o n- T e n e n tLa bo r a t o r i e s , M e mp his

, T N F a t t y Aci d Pro f i l e , % Re l a ti v e :

M I U A nal y s i s :



### 2 - 2

## To establish the comm e rcial specif i cations of the f a ts and greases relative to standard m a rket product designations, W oodson-Tenent Laboratories Division of Eurofins Scientific, Inc., Mem phis, TN perform e d a fatty acid analysis of one

sam p le each of chicken fat, yellow grease, choice white grease and tallow, Table 1. The fatty acid profiles were determ ined using gas chrom a tography (AOCS m e thod CE2-66/CE1-620, 0.01% accuracy).

In addition, W oodson-Tenent perform e d MIU (m oisture, im purities, unsaponifiables) analyses of eight (8) biofuel sam p les, two (2) sam p les each of chicken fat, yellow grease, choice white grease and tallow, Table 1.

2.4. Viscosity and Specific Gravity

In the summ e r of 2001, the UGA Biological and Agricultural Engineering (BAE) Departm e nt analyzed representative sam p les of chicken fat and yellow grease, obtained from a local com p any, to establish a range of viscosity and specific gravity f o r the design of the test f acility.

In the spring of 2002, BAE analyzed fuel sam p les collected during the test program . The UGA laboratory used a Brookfield LVT viscom eter to determ ine dynam i c viscosity (1% accuracy and 0.2% full-scale reproducibility). Specific gravity was m easured directly. The dynam i c viscosity of each fat and grease, of four (4) biofuel blends and of No. 2 fuel oil was m easured over a range of five (5) tem p eratures and five (5) shear rates. The specific gravity of each fat and grease and of No. 2 fuel oil was m easured over a range of five (5) tem p eratures. One

sam p le of each fuel was tested. All biofuel blends consist of 33% biofuel and 67% No. 2 fuel oil. No. 6 fuel oil viscosity and specific gravity are given below for reference.

F uel Dy nam i c Vi s c o s i t y, cP S p e c if ic G r a v it y

No. 2 F uel O i l 1 

### 2. 3 4, 5 

### 0. 83 4


### Choi c e W h i t e G r eas e B l end 1 

### 4. 7 4, 5 n o tan al yz ed 

### Y e l l o w G r eas e B l end 1 

### 4. 9 4, 5 n o tan al yz ed 

### T a l l o w B l end 1 

### 5. 2 4, 5 n o tan al yz ed 

### Chi c k en F a t B l end 1 

### 12. 6 4, 5 n o tan al yz ed 

### Chi c k en F a t 1 

### 23. 3 4, 5 

### 0. 89 4


### Y e l l o w G r eas e 1 

### 23. 3 4, 5 

### 0. 89 4


### T a llo w 1 

### 24. 2 4, 5 

### 0. 89 4 

### Choi c e W h i t e G r eas e 1 

### 25. 0 4, 5 

### 0. 88 4


### No. 6 F uel O i l 2 

### 490 3 

### 0. 97 3 

### Ta ble 2 , B i of ue l & Fue l Oil P h y s i c a l P r ope r t ie s

1) G o o d r u m e ta l

. , 2002; 2) B a bc o c k & W ilc ox , 1976; 3) da t aa t38 de g. C

. ; 4) da t aa t 54. 4 de g. C

. ; 5) da t aa t12. 94 s -1 s h e a r r a te



### 2 - 3

## 2.5. Ultim ate Analysis and Heating Value

PSC Analytical Services, Reading, PA analyzed a total of (33) biofuel, biof uel/f uel oil blends and f u el oil sam p les to establish their com p arative

com bustion chem istry and heating values. (All biofuel blends consist of 33% biofuel and 67% No. 2 fuel oil.) PSC used standard ASTM test m e thods for all analyses. PSC is certified/ accredited by the USEPA, NIOSH, the US Corp of Engineers, and (12) states.

F uel E ner gy Cont ent
, B t u/ Lb. A s h C ar bon Hy dr ogen Ni t r ogen O x y gen S u l f ur M o i s t u r e

Chi c k en F a t 16, 873 0. 14% 75. 3% 11. 4% 0. 04% 13. 1% 0. 006% ( t race ) Chi c k en F a t - F uel O i l Bl end 18, 223 0. 02% 82. 7% 12. 2% 0. 06% 3. 83% 0. 12% ( t race ) Y e l l ow G r eas e 16, 899 0. 02% 76. 4% 11. 6% 0. 03% 12. 1% 0. 005% ( t race ) Y e l l ow G r eas e

- F

. O

. B l end 18, 543 0. 01% 80. 2% 11. 6% 0. 07% 8. 01% 0. 13% ( t race ) Choi c e W h i t e G r eas e 16, 893 0. 08% 76. 5% 11. 5% 0. 05% 11. 6% 0. 007% ( t race ) Ch. W h t

. G r eas e - F

. O

. B l end 18, 493 0. 01% 82. 2% 12. 1% 0. 09% 5. 48% 0. 13% ( t race ) Ta l l o w 16, 920 0. 03% 76. 6% 11. 9% 0. 02% 11. 4% 0. 003% ( t race ) T a l l ow F uel - O i l B l end 18, 523 0. 06% 80. 7% 11. 9% 0. 01% 7. 22% 0. 13% ( t race ) No. 2 F uel O i l 19, 237 0. 02% 84. 0% 11. 9% 0. 01% 3. 78% 0. 35% ( t race ) Ta b l e 3 , F u e l E n erg yCo n t en t an d Ul t i mat e A n al ysi s 1

1 ) P S C A n a l yt i c al S e r v i c es , R e ad i n g , P A



## 2.6. General Characterization

The Material Safety Data Sheets (MSDS) included in the Appendix indicate that the fats and greases tested are neither hazardous nor explosive. From the test team ’s experience, these fats and greases have a distinct and unpleasant odor. However, their volatility is low and the odors do not diffuse readily.

Reports from industry indicate that chicken fat is very m i scible in fuel oil and does not readily separate in solution. The test team subjectively confirm e d

m i scibility during the dem onstration project; however, def i nitive data was not collected.

2.7. Discussion

Prelim inary laboratory analyses indicated that fats and greases could be used with the No. 2 boiler burner nozzle and that the fuel handing system designed for the test program could easily handle these biofuels. Actual com bustion testing dem onstrated these findings. Later testing confirm e d that biofuels, both singly and blended, have high heating value, low ash, and low sulfur content. Heating values for the biofuel blends tested are within 95% of the heating value of No. 2 f u el oil.

2 - 4

## The test team concluded that the chicken fat delivered on January 29, 2002 was substandard; the results from the analyses and com bustion of this biofuel were

om itted f r om the report. Initially, the particulate content in the chicken f a t caused repeated plugging of the fuel handing system filters. Flue gas testing indicated high levels of NO x 

## . Subsequent laboratory analyses showed high levels of insoluble im purities.

Two additional deliveries of chicken fat were ordered and tested. Their particulate content was negligible, and the f u el handling system f

ilters did not plug. Insoluble im purity content and em issions of NO x 

## were consistent with the other biof uels tested. Insoluble im purities were 20% and NO x 

## em issions were 66% of that f r om the initial chicken f a t delivery. This report includes the findings from the latter chicken fat deliveries.

These results conf irm the need f o r a high degree of f

iltration f o r f a ts and greases delivered as boiler f u el. Inadequately pre-f iltered biof uel causes f u el handing problem s and m a y increase gaseous em issions.

PSC Analytical Services reported problem s m a intaining data consistency due to the lack of hom ogeneity of the fuel sam p les they analyzed. The unblended biofuel sam p les separated into fractions at room tem p erature. Heating and stirring of the sam p les is necessary before they can be analyzed.

Research by Dr. John Goodrum at UGA (see References, Section 8) showed that at 40 ° C chicken fat, yellow grease, choice white grease and tallow were alm o st entirely solid. Their liquid-solid transition occurs over 40 – 48 ° C, and they are all com p letely liquid by approxim a tely 50 ° C.

All of the sam p les (biofuels, both singly and blended, and No. 2 fuel oil)

exam ined by Dr. Goodrum exhibited viscosity that transitioned fromnonNewtonian to Newtonian. The viscosity of Newtonian fluids does not vary with shear rate. The viscosity of these f u els initially decreased with increasing shear rate (non-Newtonian fluid behavior), followed by viscosity that becam e independent of shear rate when the shear rate was increased beyond 12.94s -1 

## . In other words, the viscosity curves leveled off (viscosity becam e fairly constant at a given tem p erature) once the fluid was in m o tion.

The blends of chicken fat, yellow grease, choice white grease and tallow with No. 2 fuel oil showed rheological properties very sim ilar to those of pure No. 2 fuel oil.

2 - 5

## 3. TEST FACILITY DESCRIPTION

3.1. The University of Georgia Steam Plant No. 2 Boiler

All com bustion testing was conducted using the No. 2 boiler located at the central steam plant at The University of Georgia cam pus in Athens, Georgia. Com bustion Engineering, Inc. m a nufactured this boiler in 1970. It was designed to com bust natural gas, No. 2 oil and No. 6 oil for the production of 100,000 lbs./hr. of saturated steam at 250 psig. This boiler currently operates at 100 psig. using natural gas, with No. 2 fuel oil as an alternative.

The No. 2 boiler is a pressurized, water-tube design, package unit. It includes a forced-draft fan and a single steam /air atom ized fuel nozzle (Todd Com bustion, Inc. TCD Atom izer). The TCD Atom izer nozzle was developed in 1958, and does not include air or fuel staging to reduce NO x 

## form ation. This boiler does not have com bustion air preheating or an econom izer. Flue gas em issions control is not required.

Fig. 4 , Burner nozzle for the No. 2 boiler

3 - 1

## 3.2. Steam Plant Modifications

Neither the boiler burner nozzle nor the fuel train were changed or m odified for the com bustion tests. The biofuel handling system was piped into the fuel oil delivery piping upstream of the fuel train. For further details, please refer to the Appendix, Dwg. No. SK-001, Central Steam Plant Site Plan , and Dwg. No. SK002, Boiler No. 2 Process Flow Diagram

. A 7 hp gear pum p supplied biofuel to the boiler fuel train at a m a xim u m of 22 gpm . A pressure control valve and a safety relief valve m a intained the pum p discharge pressure to a m a xim u m of 275 psig. Two (2) cast iron basket strainers in parallel protected the pum p. A shell and tube heat exchanger, which

m a intained biofuel tem p erature, was rated for 150 psig and was installed on the gear pum p suction side. 1-1/2” di a. carbon steel sch. 40 piping and 300-lb.

m a lleable iron screwed fittings were used throughout. Som e sections of the piping were steam traced.

The biofuel delivery system was m a nually controlled. Instrum e ntation consisted of two (2) fuel flow m e ters, a rotary flow indicator, and necessary pressure and tem p erature gauges.
The only m odification to the boiler was the tem porary addition of a flue gas recirculation (FGR) duct and dam p er. No m odifications were m a de to either the boiler internals or instrum e ntation.

3.3. Fuel Handling System

The biofuel handling system consisted of both m obile equipm ent and equipm ent tem porarily installed f o r the tests. Biof uels were transported to the University and stored on site in a 7,000 gallon tanker-trailer. A second tanker trailer was utilized for biofuel/ fuel oil batch m i xing. The test protocols were planned so that the quantity of biofuel available at the beginning of each testing period was sufficient for the com p letion of that test, thus avoiding the com p lexity of changing fuel supply during a test.

3 - 2

## Fig. 5 , Delivery and m i xing tankers at UGA steam plant.

Previous industrial experience had indicated that after a 24 hour exposure to extrem e winter am bient tem p eratures, a 7,000 gallon tanker load of biofuel could becom e too viscous for handling. Therefor e, all biofuel was delivered warm (over 100 ° F) and within 4 hours after loading. All biofuel suppliers were located near Atlanta, GA, less than 80 m iles from the steam plant. Delivery tankers were piped to the fuel system imm e diately after they arrived at the UGA steam plant. The fuel system continuously recirculated the biofuel to the tanker and kept it

warm and m i xed.

A heat exchanger was included in the fuel handling system prior to fuel transfer to the boiler. The heat exchanger m a intained the biofuel tem p erature to approxim a tely 165 ° F to reduce its viscosity to that of No. 2 fuel oil. The source of heat for this unit was 5 psig steam

.

3 - 3

## Fig. 6 , Fuel heating, pum ping and m i xing system

.
3.4. Flue Gas Recirculation System

The FGR system consisted of a 20 inch diam eter duct connecting the boiler flue gas breaching (at 0.0 in. wg. static pressure) and the forced draft fan inlet (at negative 0.25 in. wg. static pressure). An adjustable butterfly dam p er was installed in the duct to control flow. Pitot tube flow m easurem ents indicated that 7 to 10% of the flue gas exiting the boiler was recirculated back into the burner.

3.5. Environm ental Protection

Provisions were m a de to m a intain personnel safety and to avoid and control spills in accordance with the UGA Spill Prevention Control and Counterm easure Plan (SPCCP) and the UGA Storm W a ter Pollution Prevention Plan (SW PPP). The biofuel transfer pum p, two fuel strainers, and the heat exchanger were located in a diked containm ent area to isolate them from the sanitary sewer system

.

3 - 4

## 3. TEST FACILITY DESCRIPTION

3.1. The University of Georgia Steam Plant No. 2 Boiler

All com bustion testing was conducted using the No. 2 boiler located at the central steam plant at The University of Georgia cam pus in Athens, Georgia. Com bustion Engineering, Inc. m a nufactured this boiler in 1970. It was designed to com bust natural gas, No. 2 oil and No. 6 oil for the production of 100,000 lbs./hr. of saturated steam at 250 psig. This boiler currently operates at 100 psig. using natural gas, with No. 2 fuel oil as an alternative.

The No. 2 boiler is a pressurized, water-tube design, package unit. It includes a forced-draft fan and a single steam /air atom ized fuel nozzle (Todd Com bustion, Inc. TCD Atom izer). The TCD Atom izer nozzle was developed in 1958, and does not include air or fuel staging to reduce NO x 

## form ation. This boiler does not have com bustion air preheating or an econom izer. Flue gas em issions control is not required.

Fig. 4 , Burner nozzle for the No. 2 boiler

3 - 1

## 3.2. Steam Plant Modifications

Neither the boiler burner nozzle nor the fuel train were changed or m odified for the com bustion tests. The biofuel handling system was piped into the fuel oil delivery piping upstream of the fuel train. For further details, please refer to the Appendix, Dwg. No. SK-001, Central Steam Plant Site Plan , and Dwg. No. SK002, Boiler No. 2 Process Flow Diagram

. A 7 hp gear pum p supplied biofuel to the boiler fuel train at a m a xim u m of 22 gpm . A pressure control valve and a safety relief valve m a intained the pum p discharge pressure to a m a xim u m of 275 psig. Two (2) cast iron basket strainers in parallel protected the pum p. A shell and tube heat exchanger, which

m a intained biofuel tem p erature, was rated for 150 psig and was installed on the gear pum p suction side. 1-1/2” di a. carbon steel sch. 40 piping and 300-lb.

m a lleable iron screwed fittings were used throughout. Som e sections of the piping were steam traced.

The biofuel delivery system was m a nually controlled. Instrum e ntation consisted of two (2) fuel flow m e ters, a rotary flow indicator, and necessary pressure and tem p erature gauges.
The only m odification to the boiler was the tem porary addition of a flue gas recirculation (FGR) duct and dam p er. No m odifications were m a de to either the boiler internals or instrum e ntation.

3.3. Fuel Handling System

The biofuel handling system consisted of both m obile equipm ent and equipm ent tem porarily installed f o r the tests. Biof uels were transported to the University and stored on site in a 7,000 gallon tanker-trailer. A second tanker trailer was utilized for biofuel/ fuel oil batch m i xing. The test protocols were planned so that the quantity of biofuel available at the beginning of each testing period was sufficient for the com p letion of that test, thus avoiding the com p lexity of changing fuel supply during a test.

3 - 2

## Fig. 5 , Delivery and m i xing tankers at UGA steam plant.

Previous industrial experience had indicated that after a 24 hour exposure to extrem e winter am bient tem p eratures, a 7,000 gallon tanker load of biofuel could becom e too viscous for handling. Therefor e, all biofuel was delivered warm (over 100 ° F) and within 4 hours after loading. All biofuel suppliers were located near Atlanta, GA, less than 80 m iles from the steam plant. Delivery tankers were piped to the fuel system imm e diately after they arrived at the UGA steam plant. The fuel system continuously recirculated the biofuel to the tanker and kept it

warm and m i xed.

A heat exchanger was included in the fuel handling system prior to fuel transfer to the boiler. The heat exchanger m a intained the biofuel tem p erature to approxim a tely 165 ° F to reduce its viscosity to that of No. 2 fuel oil. The source of heat for this unit was 5 psig steam

.

3 - 3

## Fig. 6 , Fuel heating, pum ping and m i xing system

.
3.4. Flue Gas Recirculation System

The FGR system consisted of a 20 inch diam eter duct connecting the boiler flue gas breaching (at 0.0 in. wg. static pressure) and the forced draft fan inlet (at negative 0.25 in. wg. static pressure). An adjustable butterfly dam p er was installed in the duct to control flow. Pitot tube flow m easurem ents indicated that 7 to 10% of the flue gas exiting the boiler was recirculated back into the burner.

3.5. Environm ental Protection

Provisions were m a de to m a intain personnel safety and to avoid and control spills in accordance with the UGA Spill Prevention Control and Counterm easure Plan (SPCCP) and the UGA Storm W a ter Pollution Prevention Plan (SW PPP). The biofuel transfer pum p, two fuel strainers, and the heat exchanger were located in a diked containm ent area to isolate them from the sanitary sewer system

.

3 - 4

## 4. COMBUSTION DEMONSTRATION

4.1. Introduction

Industrial boiler operating experience and data were obtained while firing natural gas, No. 2 fuel oil, biofuels, and biofuels blended with No. 2 fuel oil. Baseline

com bustion testing was conducted by firing natural gas and fuel oil. Testing was conducted both with and without flue gas recirculation and with a range of boiler loads to evaluate em issions and com bustion efficiencies under a wide range of operating conditions. The tests dem onstrated that the biofuels burn efficiently, cleanly, readily, without odor and without dam a ge to boiler equipm ent.

4.2. Test Schedule

The University of Georgia in Athens, GA is subject to m ild winter conditions and considers the winter heating season to extend from late Novem b er to m i dFebruary. Steam dem a nd on the central steam plant is in the 100,000 to 200,000 lb/hr range during the winter heating season. This dem a nd reduces to less than 50,000 lb/hr during the summ e r. Throughout the year, daily load peaks in the early m o rning.

The project team scheduled the tests during the winter heating season to allow for testing of the No. 2 boiler at m a xim u m load. The tests began January 28, 2002 and continued daily for three weeks until February 15, 2002. Maxim u m load tests were conducted in the m o rning, part load tests in the afternoon. A follow-up test on chicken fat was conducted on March 15, 2002.

In general, the sequence of the testing was chicken fat and blend, yellow grease, choice white grease and blend, tallow, yellow grease blend and tallow blend. All blends consisted of 33% fat or grease and 67% No. 2 fuel oil. Natural gas and No. 2 fuel oil testing was conducted periodically throughout the test period.

4.3. Boiler Efficiency

Boiler efficiency is calculated as boiler steam energy output (btu/hr), less feedwater energy input, as a percentage of boiler fuel energy input (btu/hr). Steam plant instrum e ntation m easured the flow (lb/hr) and pressure (psig) of the saturated steam produced by the boiler. Feedwater energy input was based on the tem p erature at the deaerator.

Fuel energy input is the product of the flowrate and the energy content of the fuel. The flowrate was determ ined from the flow at the boiler burner nozzle flowm e ter divided by the tim e interval between m e ter readings. PSC Analytical Services analyzed sam p les of each fuel to determ ine specific energy content.

4 - 1

### Fig. 7 , B o ile r E f f i c i e n c y , B i of ue l s a nd Fue l O i l

70 % 72 % 74 % 76 % 78 % 80 % 82 % 84 %

T Y C W W B Y B C B F T B Fue l s

1) M a x

. an d p a r t l o a d c o n d i t i o ns ar e av er

a g e d

. 2 ) E rro r ba rs s h o w s t d. e rror, n = 4 o r gre a t e r.

T 7 4. 9 % T A LL O W Y 7 5

. 6 % YEL L O W G R EASE C 7 5

. 9 % C H I C KEN F A T W 7 6

. 4 % C H O I CE W H I T E G R EASE W B 7 7

. 6 % C HO I C E W H I T E G R EASE - FUEL O I L BL EN D YB 7 8

. 0 % YEL L O W G R EASE - F U EL O I L BL END C B 7 9

. 0 % C HI C KEN F A T - F U EL O I L BL END F 8 0

. 2% No. 2 F U E L O I L T B 8 1

. 9 % T AL L O W - FUEL O I L BL EN D Fu e l A b rev. A v era g e E f

fi ci en cy Fu e l s



## Fig. 7 , Legend

4 - 2

### Fi g. 8 , B o i l e r E ffi ci e n cy, M ax. an d P a r t L o ad C o n d i t i o n s

72% 74% 76% 78% 80% 82% 84%

ABC D E F


### Fue l / B o i l e r Loa d

Error bars show st d. error, n=4 or great er.



### A 75. 6% B I O F UE LS @ M AX

. LO A D B 77. 2% B I O F UE LS @ P A R T LO A D C 77. 4% B L E NDE D B I O F UE LS @ M AX

. L O A D D 80. 0% No. 2 F U E L O I L @ M AX

. LO A D E 80. 5% No. 2 F U E L O I L @ P A R T LO A D F 8 0

. 9 % BL EN D E D BI O F U E L S @ PAR T LO AD Fue l/ Loa d A verag e E f

f i ci en cy Fue l & B o ile r Loa ding



## Fig. 8 , Legend

There was no significant difference in boiler e fficiency when using 100% #2 fuel oil and blends with 33% biofuel oil according to a Student’s t-test at the α = 0.05 significance level. Boiler efficiency of #2 fuel oil was significantly higher com p ared to biofuel oil alone. Boiler efficiency was significantly hi gher using tallow blend com p ared to #2 fuel oil under half load conditions.

4 - 3

### Fi g. 9 , B o i l e r E ffi ci e n cy,

w i t h a nd w / o FG R

70% 72% 74% 76% 78% 80% 82%

A B C D E F


### Fue l / FG R O p e r a t i o n

1) M a xi m u m boi l e r l o ad condi t i ons shown. 2) Error bars show st d. error, n=4 or great er. 3) 1% error assum e d for case E.



### A 74. 7% B I O F UE LS

, w / o F G R B 77. 0% B I O F UE LS w i t h F G R C 77. 2% B L E NDE D B I O F UE LS w / o F G R D 77. 4% B L E NDE D B I O F UE LS w i t h F G R E 79. 6% No. 2 F U E L O I L w / o F G R F 8 0

. 4 % N o . 2 FU E L OIL w i th FGR Fue l/ FGR

. O p erat i o n A verag e E f

f i ci en cy Flue Ga s R e c i r c ula t ion ( F GR ) Sta t u s



## Fig. 9 , Legend

4.4. Com bustion Characteristics

The steam plant did not experience any unusual operating problem s while burning biof uel or biof uel blends. The boiler lit of f quickly and ran quietly. There were no fat and grease odors in the plant.

Observations through the furnace sight glasses indicated that biofuels generally burn with a flam e that is m o re yellow-colored and widely dispersed than with either natural gas or No. 2 fuel oil. However, the flam e pattern was well contained within the furnace, as was verified by later internal inspection of the furnace.

4 - 4

## At m a xim u m load, fuel pressure to the boiler nozzle averaged 160 psig for unblended biofuels, 157 psig for blended biofuels, and 119 psig for No. 2 fuel oil. Atom izing steam pressure averaged 97 psig under all conditions.

A therm o couple was installed in the furnace to m easure its internal tem p erature. The therm o couple projected approxim a tely 3 ft. into the back of the furnace, at the flue gas backpass. Tem p erature readings were read from a handheld digital th e rmo me t e r

.

Fig. 10 , Furnace tem p erature m easurem ent system

4.5. Inspection of Boiler Internals

The test team inspected the interior of the boiler after several m onths of firing natural gas exclusively; then, after firing No. 2 fuel oil exclusively; and, finally, after three weeks of biofuel com bustion testing. The test team observed that the water tube exterior surfaces were clean and soot-free after natural gas firing. The tube surfaces were soot-covered, black-col ored, and som e what greasy after firing with No. 2 fuel oil.

Following biofuel burning, the interior of the furnace appeared to be alm o st as clean as it was after firing natural gas, and m u ch cleaner than it was after burning No. 2 fuel oil. A slight blackening of the tube surfaces, following the flam e pattern, was observed in the front half of the 25-ft. long furnace.

4 - 5

## A scattering of baked-on solid deposits (each approxim a tely 2-3 mm in diam eter) was found on the tube surfaces in the back half of the furnace. The UGA Chem ical Analysis Laboratory analyzed three (3) sam p les of this m a terial with an ICP m a ss spectrom e ter and found that they consist predom inately of the elem ents Fe, Na, P, K, and Ca.

Fig. 11 , Inspection of boiler heat transfer surfaces after testing biofuels

4.6. Discussion

The standard error calculated for the efficiency data ranged from 0.3% to 1.4%, plus or m i nus, with one data point showing a 2.6% +/- standard error, n = 4. The instrum e ntation used is standard industrial class equipm ent, and was not specially calibrated f o r this test. The greatest potential f o r error is the tim e recording taken between fuel m e ter readings. A tim e interval of 13 m i nutes was the m i nim u m used. All tim e readings were taken with a wristwatch to the nearest m i nute.
There was no significant difference in effici ency under part load conditions versus full load according to an unpaired Student’s t-test at the α = 0.05 significance level. Also, there was no significant difference in efficiency with or without FGR. However, com bustion with FGR resulted in significantly less excess air in the flue gas and indicates m o re com p lete com bustion and less loss of energy to the stack.

4 - 6

## 5. EMISSIONS TESTING

5.1. Particulate Testing
Advanced Air Consultants Inc. (AAC), Murrayville, GA perf orm e d em issions tests for condensible (both organic and inorganic) and non-condensible particulate. Two test runs, each one hour long and conducted under norm a l boiler operation, were perform e d on each of five different fuels (chicken fat, yellow grease, choice white grease, tallow, and No. 2 fuel oil). Sim u ltaneously with the particulate tests, the UGA Engineering Outreach test team m easured gaseous

em issions.

AAC conducted all particulate testing according to the reference m e thods developed by the US EPA and prom ulgated in the Code of Federal Regulations, Title 40, Parts 51 and 60. AAC is certified per NELAC procedures to perform EPA Method 5 particulate m easurem ent. All of the test equipm ent was

m a nufactured and calibrated as specified in the EPA m e thods.

The particulate testing location was in a straight section of the No. 2 boiler breaching, between the boiler and a com b ined boiler stack. The num ber of velocity traverse points was chosen based on the distance of the test ports from up and downstream flow disturbances. Flow disturbances were located 2.5 diam eters upstream and 1.0 diam eters downstream from the test ports. Twenty traverse points were sam p led.

Fig. 12. Inserting particulate testing probe into breaching.

5 - 1

## AAC used a sam p ling train consisting of a stainless steel nozzle, stainless steel union, stainless steel lined probe, glass filter holder with Teflon filter support, four glass im pingers, um bilical cord, vacuum pum p, dry gas m e ter and orifice. Both the probe and filter com p artm ent were heated to 250 deg. F. The im pingers were placed in an ice bath to rem ove m o isture from the sam p le gas stream . A "S" type pitot tube and an inclined m a nom eter m easured the gas velocity pressures. A type K therm o couple and a digital therm o m e ter m easured the gas tem p erature. The Denver Instrum e nts Model A-250 analytical balance in the AAC laboratory weighed the particulate sam p les.

In accordance with US EPA Method 19 (40CFR60), AAC calculated fuel FFactors using the fuel analysis data presented in Section 3 of this report. FFactors are used to calculate em ission rates in pounds per m illion Btu, per US EPA m e thodology.

The US EPA “F Factor” technique is a m o re convenient m e thod to determ ine

em issions on a m a ss per unit heat input basis. This technique allows the calculation of em issions without the need for precise m easurem ent of fuel flow and com bustion efficiency.

Fue l F

- F a c t or , Fd Chi c k en F a t 8

, 865 Y e l l o w G r eas e 9

, 108 Choi c e W h i t e G r eas e 9

, 145 T a l l o w 9, 179 No. 2 F uel O i l 8

, 850

S o ur c e : A d va nc e d A i r C o ns ulta nts
, Inc ., Mur r a y v ille , G A

R e f .: F eder al

R egi s ter , 40: 194, P a rtV

, O c t

. 6, 1975, 

### Ta ble 4 , F- Fa c t ors

F d is t h e r a t i o of

t h e qua nt it y of

dry e f

f l ue ntga s ge ne r a t e d by

c o m b u s tio n to th eg r o s s c a lo r i f i c va lu eof th ef u e l , d s c f /1 0 6 Btu

.



## AAC also m onitored sm okestack opacity. Maxim u m opacity with chicken fat was 4% and yellow grease was 6%. There was no opacity observed while burning tallow. Opacity was not m onitored while burning choice white grease.

Opacity testing was not perform e d in strict accordance with GA EPD com p liance regulations, which require an average value for a series of opacity observations over a one-hour period. Instead, opacity testing during the program consisted of a series of spot observations. However, all opacity readings were taken by GA EPD-certified opacity readers.

5 - 2

### Fi g. 1 3 , P a r t i c u l at e E m i ssi o n s, B i of ue l s a n d Fu e l O i l

0. 00 0 0. 01 0 0. 02 0 0. 03 0 0. 04 0 0. 05 0 0. 06 0 0. 07 0 0. 08 0 0. 09 0



### Fu e l s lb ./m m B t u

c o nd

. pa rt i c ul at e 0. 00 3 0

. 0 0 5 0. 01 2 0

. 0 0 3 0. 00 6

no n- c o nd

. pa rt i c ul at e 0. 00 9 0

. 0 1 4 0. 01 0 0

. 0 3 8 0. 07 7 Y T F W C



### 1 ) Test co n d itio n s : m a x i m u m b o iler lo adwith FGR. 2) C ondensi b l e part i c ul at e = organi c + i norgani c condensi b l e part i c ul at e. 3) Tot a l part i c ul at e = non-cond. + cond. part i c ul at e. 4) Error bars show st d. e rror for total particulate.



### Y T F W C F uel Ab re v

. F uel

CHI CK E N F A T YEL L O W G R EASE T A LLO W N o . 2 FU E L OIL C H O I C E W H I T E G R EASE



## Fig. 13. Legend

5.2. Gaseous Em issions Testing

The UGA Engineering Outreach team used an ENERAC 3000E analyzer to

m easure the gaseous em issions from the No. 2 boiler. The team recorded both average and instantaneous m easurem ents of flue gas concentrations for oxygen, carbon m onoxide, carbon dioxide, com bustible gases, excess air, nitric oxide, nitrogen dioxide, NO x 

## (NO + NO 2 

## ), and sulfur dioxide. The analyzer software

5 - 3

## program enabled the recording of em issions data directly to a spreadsheet file on the hard drive of a laptop com puter. Data was recorded during steady state operations for each fuel tested, at both m a xim u m and part loads and at each FGR dam p er setting.

The ENERAC 3000 portable em issions analyzer is a self-contained, extractive f l ue gas m onitoring system utilizing electrochem ical sensors with an internal

sam p le pum p designed for 600-900 cc/m i nute. A separate vacuum pum p extracted flue gas from a breaching port and discharged it to the ENERAC. Teflon tubing interconnected a filter probe in the breaching through two m o isture condensers to the vacuum pum p and then to the analyzer.

The ENERAC sensors use an electronically controlled circuit to m i nim i ze zero drift and reject cross interference from other com pounds, in com p liance with EPA Conditional Test Methods (CTM) –022, -030 and –034. The perform a nce specifications of the CTM-022 m e thod ar e equivalent to US EPA Method 7E requirem e nts. The accuracy of the sensors is +/-2%, and they are capable of operating at 1.5 orders of m a gnitude of gas concentrations.

Equipm ent was calibrated several tim es per week, and was checked daily for accuracy. The system was allowed to autozero daily. Span calibration of CO, NO, SO, NO 2 

## was perform e d 2-3 tim es per week using calibrated gases (CO at 78 ppm , NO at 124 ppm , SO 2 

## at 25 ppm , and NO 2 

## at 92 ppm .)

Fig. 14. Logging of em issions data from Enerac 3000E.

5 - 4

### Fi g

. 15 , N O x 

### E m i ssi on s

0 20 40 60 80 10 0 12 0 14 0

N

w. FG R Y

w. FG R T

w. FG R Y B

w. FG R N Y B C B

w. FG R T F

w. FG R Y T B

w. FG R WB

w. FG R F T B C B W B W

w. FG R W C

w. FG R C



### Fu el / FG R O p erat i o n NO x 

### , p p m

1) Al l t e st s were conduct e d at m a xi m u m boi l e r l o ad. 2) Error bars show std. error calculated for cases: CB w ith FGR (n=2) and T w/o FGR (n=3). 2% error assum e d for all of the other cases.

w/o FGR w . FGR % r e duct i on w/o FGR w . FGR de lta N 8 0 5 4 32. 5 % 1, 98 3 2

, 0 1 0 27 Y 9 3 7 1 23. 7 % 1, 75 5 1

, 8 3 0 75 T 9 0 7 7 14. 4 % 1, 82 4 1

, 9 2 8 104 Y B 89 80 10. 1 % 1, 77 3 1

, 8 1 1 38 CB 99 90 9. 1% 1, 75 6 1

, 8 4 3 87 F 9 8 9 1 7

. 1 % 1, 83 6 1

, 9 0 1 65 T B 98 95 3. 1% 1, 71 4 1

, 7 9 0 76 W B 101 97 4. 0% 1, 86 0 1

, 9 5 4 94 W 108 105 2. 8% 1, 85 5 1

, 8 8 6 31 C 118 112 5. 1% 1, 77 6 n

. a

. n

. a

. F u r n ace T e mp e rat u re, d e g

. F

. NO x emi ssi o n s, p p m Fue l L e g e n d

C H O I C E W H I T E G R EA SE - F U EL O I L B L E N D CH O I CE W H I T E G R E A S E C H IC K E N FAT NAT U RA L G A S YEL L O W GR EA SE T A LLO W YEL L O W GR EA SE

- F U EL OI L BL EN D C H I C KEN F AT - F U EL O I L BL EN D N o . 2 FU E L OIL T A LLO W - F U E L O I L B L E N D



## Fig. 15. Legend

5 - 5

### Fi g

. 1 6 , S O 2 

### E m is s i o n s

0 20 40 60 80 10 0 12 0 14 0

C N

w . FG R N W

w . FG R W Y C

w . FG R Y

w . FG R T T

w . FG R Y B Y B

w . FG R T B T B

w . FG R W B C B C B

w . FG R F W B

w . FG R F

w . FG R
Fue l/ FG R O p e r a t ion SO 2 , ppm



### 1) Al l t e st s were conduct e d at m a xi m u m boi l e r l o ad. 2) Error bars show std. error (n=2 or greater) calculated for cases: Y, YB, F, W
, and C with FGR; and cases T, C B and W w/ o FGR

. 2% error assum e d for al l of th e other cases.

w/o FGR w

. FGR de lt a N 0 Y 0 W 0 C 0 T 1 Y B 20 48 28 T B 59 69 10 W B 69 10 9 4 0 CB 72 80 8 F 8 7 N o . 2 FU E L OI L NAT U RA L G A S YE L L O W GR EA SE C H O IC E W H ITE GR E A S E CHI CK EN F A T TAL L OW YE L L O W GR EA SE - F U E L O I L BL EN D TA L L OW - FU E L OIL B L E N D CHO I C E W H I T E G R EA SE - F U E L O I L BLEND CHI CK EN F A T - F U EL O I L BLEND Fu e l Le ge nd SO 2 emi s s i o n s, p p m

0 0 1 1 0 0 0 0 4 3

1 2 7 4 0



## Fig. 16. Legend

5 - 6

### Fig. 1 7 , C O 2 

### E m i ssi o n s

5 6 7 8 9 10 11 12 13 14 15

W C B T C W B W

w . FG R Y T B Y B Y

w . FG R C

w . FG R CB

w . FG R TB

w . FG R T

w . FG R WB

w . FG R YB

w . FG R N N

w . FG R F F

w . FG R


### Fue l/ F G R O p e r a t ion CO 2 

### , %

1) A l l t e s ts wer e c onduc t ed at m a x i m u m boiler load. 2) E r r o r bar s s how s t d. er r o r ( n = 2 or gr eat er ) c a lc ulat ed f o r c a s e s : CB

, F

, and W wit h F G R, a nd T and W w/ o F G R. 3) 2% er r o r as s u m ed f o r

all of t he ot her c a s e s

.



### w/o FGR w. FGR de lt a 

### W 6 .9 7

. 5 0 .6 CB 7. 0 8

. 0 1. 0 T 7 .1 8

. 2 1 .1 C 7 .3 7

. 9 0 .6 W B 7. 3 8

. 3 1. 0

Y 7 .6 7

. 8 0 .2 T B 7. 7 8

. 1 0. 4 Y B 7. 7 8

. 5 0. 8 N 9 .0 1 0

. 0 1 .0 F 12. 6 13. 5 0

. 9 F u e l L eg en d CO 2 

### emi ssi o n s , %

N o . 2 FU E L OIL C H O I C E W H I T E G R EASE C H I C KEN F A T - F U EL O I L BL EN D T A LLO W CHI CK E N F A T C H O I C E W H I T E G R EASE - F U EL O I L BL EN D YEL L O W G R EASE T A L L O W - F U EL O I L BL EN D YEL L O W G R EASE - F U EL O I L BL EN D NA T URA L G A S


## Fig. 17. Legend

5 - 7

### Fi g

. 18 , C O E m is s i o n s

0 5 10 15 20 25 30 35 40 45

C C

w . FG R C B T B

w . FG R T B Y B N C B

w . FG R T W B Y W

w . FG R W Y

w . FG R F T

w . FG R N

w . FG R F

w . FG R WB

w . FG R


### Fue l/ FG R O p e r a t ion CO , p p m



### 1) Al l t e st s were conduct e d at m a xi m u m boi l e r l o ad. 2) Error bars show st d. error (n=2 or great er) cal cul a t e d for cases: Y, T, C B
, F, W
, and C wi th FGR
, and T w/ o FGR. 2% error assum e d for all of the other cases.

w/o FGR w . FGR de l t a C 0 CB 8 1 4 6 TB 9 9 0 YB N 1 T 1 W B 14 39 25

Y 1 W 1 F 2 C H O IC E W H ITE G R EA SE - F U EL O I L B L EN D Y E L L O W G R EA SE C H O IC E W H ITE G R EA SE not av ai l abl e F u e l L eg en d C O e m is s i ons , ppm

No. 2 F U EL O I L CHI CKE N F A T C H I C K EN FAT - FU EL OIL B L EN D T A LLO W - F U E L O I L B L E N D Y E L L O W G R EA SE - FU E L O I L BL E N D NAT URA L G A S T A LLO W 8 8

0 2 2 1 2 4 2 1 7

4 1 9 5 7 1 6

- 1 0 2 3 3 

## Fig. 18. Legend

5 - 8

### Fi g

. 1 9 , C o m b u s t i b l e s in F l u e Ga s

0. 00% 0. 05% 0. 10% 0. 15% 0. 20% 0. 25% 0. 30% 0. 35%

C Y

w . FG R CB

w . FG R C

w . FG R N T B W B W

w . FG R Y C B T F

w . FG R F N

w . FG R T

w . FG R TB

w . FG R WB

w . FG R W Y B

w . FG R YB



### F u el / F G R O p erat i o n C o m b ust i bl e

G ases , %

1) A l l t e s ts we r e c onduc t ed at m a x i m u m b o iler load. 2) E r r o r bar s s how s t d. er r o r ( n = 2 or gr eat er ) c a lc ulat ed f o r

c a s e s : Y

, T

, Y B

, CB

, F

, W

, and C wit h F G R; and c a s e s T

, CB and W w/o F G R. 3) 2% er r o r as s u m ed f o r

all of t he ot her c a s e s

.

w/o F G R w . FGR delta C H I C K E N F A T 0. 1 4 % 0

. 2 3% 0. 0 9 % N A T U R A L G A S 0

. 2 3% 0. 3 1 % 0

. 0 8% T A LL O W - F U E L O I L B L E N D 0

. 2 3% 0. 3 1 % 0

. 0 8% CH O I CE W H I T E G R EA SE - F U EL O I L BLEND 0

. 2 3 % 0

. 31 % 0

. 0 8 % YELL O W G R E ASE 0

. 23 % 0

. 1 6 % -0

. 0 7% C H I C K E N F A T - F U E L O I L B L E N D 0

. 2 6% 0. 1 9 %

- 0. 07 % T A LL O W 0. 2 8 % 0

. 3 1% 0. 0 3 % N o . 2 FU E L OIL 0 .3 1 % 0

. 3 1 % 0 .0 0 % C H OIC E W H ITE GR E A S E 0

. 3 1 % 0 .2 3 % -0 .0 8 % YELL O W G R E ASE - F U EL O I L BLEND 0

. 3 1 % 0

. 31 % 0

. 0 0 % Le ge nd C o m bus tible s in Flue Ga s , %



## Fig. 19. Legend

5.3. Odor Sam p ling

At no tim e during the dem onstration program did the test team receive any

com p laints about odor originating from the steam plant. Test team m e m b ers, BAE faculty and staff associated with the project, and the steam plant personnel (10 individuals, in total) m onitored the cam pus for odor and recorded their findings at least twice for each test series. Odor was m onitored (36) tim es throughout the dem onstration program . Each odor test began at the steam plant; and, if the wind speed exceeded 1 to 2 m ph, was repeated again 0.5 to 1.0 m iles down wind of the steam plant. A check of the UGA cam pus weather website preceding each test confirm e d the wind direction and velocity. All odor testers were asked to verify that they were not suffering from any nasal congestion.

5 - 9

## Odor was not detected during any of the (17) tests taken down wind of the steam plant. However, there were noticeable fat and grease odors detected in the vicinity (within 100 ft.) of the biofuel tankers.

5.4. Flue Gas Recirculation (FGR) Flow Measurem ent
Approxim a tely 7 to 10 % of the boiler breaching flue gas was recirculated to the forced draft fan inlet with the recirculation dam p er 100% open. The test team perform e d a series of flowrate m easurem ents using standard pitot tube traverse

m e thodology. Measurem ents were m a de for all fuels, at both full and part load conditions.

The arrangem e nt of the FGR ducting m a de pitot traversing difficult and im peded the accuracy of the tests. However, the tests are deem ed accurate within 25%, which is sufficient to determ ine that the system was functioning.

5.5. Discussion

The m o st significant source of data inaccuracy during the particulate testing is the % of isokinetic sam p ling, which is the ratio of flue gas flow rate to the sam p ling flow rate. The GA EPD allows these rates to average within 10% of each other during a one-hour sam p le period, i.e., a test accuracy of 10%+/-. For com p liance testing, two out of three sam p les m u st m eet the 10% criteria. During this test program , at least one particulate test for each fuel m e t the EPD requirem e nt.
Odor and opacity test readings were subjective. Their degree of accuracy cannot be docum ented. Statistical analysis using the Student’s t-test statistic was used to test for significant difference ( α = 0.05) for other data using Sigm a-Plot version 2.01 software (Jandel Corporation, San Raphael, CA).

Total particulate em issions from biofuel oil as a group were not significantly different from particulate em issions from #2 fuel oil. However, total particulate

em issions from chicken fat fuel was signifi cantly higher than the other biofuel oils and both chicken fat and choice white fat particulate em issions were significantly higher than #2 fuel oil. Particulate em issions from chicken fat fuel were significantly higher than those from choice white grease.

In general, the m o st significant source of data inaccuracy during gaseous em ission testing is the specified 2%+/- accuracy of the ENERAC sensors.

Most of the NO x 

## form ed during com bustion is from high tem p erature oxidation of atm o spheric nitrogen. This NO x 

## is referred to as “therm al NO x 

## and is popularly

m odeled as an exponential function of flam e tem p erature and a square root function of oxygen concentration. Thus, the form ation of therm a l NO x 

## can be controlled by m a nipulating the flam e tem p erature or the oxygen concentration (Agrawal and W ood, 2002). Average em issions of NO x 

## from the com bustion of

5 - 10

## all biofuel oils were not found to be signi ficantly different than em issions from #2 fuel oil (Student’s unpaired t-test, 0.05 significance level). However, the NO x 

## em issions from chicken fat alone were significantly higher than the other biofuel oils and #2 fuel oil and natural gas. This result is confounding, the chicken fat fuel contained higher ash (Table 3), however, total nitrogen was low and

com bustion conditions were identical to the other com bustion tests.

The procedures used in this testing of FGR both reduced oxygen (which decreases NO x 

## ) and increased furnace tem p erature (which increases NO x 

## , see Fig. 15, Legend). The net result was that for all cases when flue gas recirculation was used, NO x 

## decreased in the range of 2.8% to 32.5%, significantly different from

em issions without FGR according to a Student’s paired t-test ( α = 0.05). The discrepancy between the factors sim u ltaneously driving the increase and the decrease of NO x 

## should be further studied.

The ENERAC m a y have recorded SO 2 

## readings significantly lower than actual. Gas sam p les extracted from the breaching were cooled below the SO 2 

## condensation tem p erature (to rem ove excess m o isture) before the sam p le was analyzed by the ENERAC. However, the relative SO 2 

## data values presented in Fig. 16 are considered valid because this data is proportional to % sulfur analyzed in the fuels. The biofuel oils had practically zero am ounts of SO 2 

## in em issions and they were significantly less than the biofuel oil blends and #2 fuel oil. Additionally, biofuel oil blends had significantly lower SO 2 

## em issions that #2 fuel oil.

There were significantly lower CO 2 

## em issions from biofuel oil versus #2 fuel oil. Additionally, 33% blends of biofuel oil in #2 fuel oil had significantly lower CO 2 

## em issions.

There was no significant difference in CO em issions between the biofuel oils, blends, or #2 fuel oil. FGR had no significant effect on CO or com bustibles

em issions. Chicken fat and yellow grease em issions were significantly lower in

com bustibles than #2 fuel oil.

5 - 11

## 6. CONCLUSIONS
Fats and greases were dem onstrated as industrial boiler fuels. These biofuels easily and

econom ically displace No. 2 fuel oil using the sam e boiler operating procedures as fuel oil without any m odifications to internal boiler com bustion equipm ent. The biofuels need to be kept warm during cold weather in order to flow through piping and equipm ent. Wh en heated to about 160 ° F. biofuels are easily atom ized and ignited. Construction costs for the pum p, heat exchanger, instrum e nts, piping, valves, fittings, and electrical system f

o r a system to m a intain the 160 ° F. tem p erature and to transfer fuel from storage to the boiler was less than $31,000. This total does not include the cost of engineering or the procurem ent cost for the heat exchanger. Extra costs would be incurred if separate storage tanks were needed for biofuel storage. Research should be accom p lished focusing on the issues associated with using existing No. 2 fuel oil storage tanks for the storage of biofuel and biofuel blends.

Air em issions from the com bustion of the biofuel oils m e t or exceeded state and federal air quality perm it requirem e nts f o r The University of Georgia. Nitrogen oxides and particulate em issions were com p arable to em issions from the com bustion of No. 2 fuel oil, Table 4. Sulfur dioxide em issions and deposits on boiler tubes were sim ilar to those encountered when burning natural gas. Biofuels also have low carbon m onoxide

em issions. The fuel nozzle used in the UGA boiler was a 1950’s design and no special procedures were used to m i nim i ze em issions through nozzle placem ent. Flue gas recirculation (FGR) was tested with 7% to 10% of flue gas being recirculated. FGR did not significantly increase boiler efficiency but did significantly reduce NO x 

## em issions

com p ared to tests without FGR according to a Students t-test at the α = 0.05 significance level. NO x 

## em issions were not reduced enough to m eet regulations for new sources and for non-attainm e nt areas. Additional testing is required using low NO x 

## nozzle designs and other m e thods for m i nim i zing em issions. Wh en the boiler was operated at half load, boiler efficiency was significantly greater for a blend of 33% tallow with 77% #2 fuel oil than when using 100% #2 fuel oil ( α = 0.05).

The biofuel oils have high heating value; low am ounts of ash, nitrogen, and m o isture; and negligible am ounts of sulfur. Heating values of the biofuel oil blends tested are within 95% of the heating value of No. 2 fuel oil. Th e specific gravity of the biofuels is close to that of No. 2 fuel oil. The biofuels are m o re viscous than No. 2 fuel oil, but m u ch less viscous than No. 6 fuel oil. However, a blend of 30% biofuel with No. 2 fuel oil has a viscosity that is close to that of No. 2 fuel oil. Boiler efficiency while burning biofuel oil is com p arable to that of No. 2 fuel oil.

6 - 1NO x, lb ./M M B tu F i l t er ab l e P M

, lb ./M M B tu C O, lb ./M M B tu SO 2 , lb ./M M B tu 5

UG A Bo i l e r No

. 2 E m i ssi o n s , T e sted a t M a x. St e a m L o a d 1 : C h ic k e n Fa t, c o n t ro l l e d w i th FGR 7 0. 15 6 0

. 0 7 7 0. 00 8 0. 00 0 Y e l l o w Gre a s e , c o n t r o lle d w i th FGR 7 0. 09 7 0

. 0 0 9 0. 01 6 0. 00 1 Ch oi c e W h i t e G r ea s e , c o n t r o l l e d w i t h F G R 7 0. 15 0 0

. 0 3 8 0. 01 4 0. 00 0 T a ll o w , c o n t r o lle d w i th F G R 7 0. 10 1 0

. 0 1 4 0. 01 8 0. 00 7 N o . 2 Fu e l Oi l, c o n t r o ll e d w i th FGR 7 0. 11 6 0

. 0 1 0 0. 00 4 0. 21 9

U G A B o ile r N o . 2 E m i s s i o n s , E s tim a t e d a t M a x

. S t e a m Loa d 2 : C h ic k e n Fa t, u n c o n t r o l l e d ( w /o L N B o r FGR ) 0

. 1 6 4 n ot av ai l a bl e 0

. 0 00 0. 00 0 Y e l l ow G r e a s e , u n co nt rol l ed ( w / o LNB or F G R) 0

. 1 2 7 n ot av ai l a bl e 0

. 0 12 0. 00 0 Ch oi c e W h i t e G r ea s e , un c o n t r o l l e d ( w / o LN B o r F G R) 0

. 1 5 4 n ot av ai l a bl e 0

. 0 14 0. 00 0 T a l l o w , u n co nt rol l ed ( w / o LNB or F G R) 0

. 1 1 8 n ot av ai l a bl e 0

. 0 12 0. 00 2 N o

. 2 Fu e l Oi l, u n c o n t r o ll e d ( w /o L N B o r FGR ) 0

. 1 2 5 n ot av ai l a bl e 0

. 0 03 0. 15 0

Chi cken F a t
, b l en ded 6

, un c o n t r o l l e d 0

. 1 3 7 n ot av ai l a bl e 0

. 0 08 0. 12 4 Y e l l o w G r ea s e , bl en de d 6

, un c o n t r o l l e d 0

. 1 2 2 n ot av ai l a bl e n ot av ai l a bl e 0. 03 4 Ch oi c e W h i t e G r ea s e , bl en de d 6

, un c o n t r o l l e d 0

. 1 4 4 n ot av ai l a bl e 0

. 0 12 0. 11 9 T a l l ow , bl en de d 6

, un c o n t r o l l e d 0

. 1 2 9 n ot av ai l a bl e 0

. 0 08 0. 10 2

Chi cken F a t
, b l en ded 6 , c o n t r o lle d w

. F G R 7 0

. 1 2 5 n ot av ai l a bl e 0

. 0 14 0. 13 8 Y e l l o w G r ea s e , bl en de d 6 , c o n t r o lle d w

. F G R 7 0

. 1 0 9 n ot av ai l a bl e n ot av ai l a bl e 0. 08 3 Ch oi c e W h i t e G r ea s e , bl en de d 6 , c o n t r o lle d w

. F G R 7 0

. 1 3 8 n ot av ai l a bl e 0

. 0 33 0. 18 8 T a l l ow , bl en de d 6 , c o n t r o lle d w

. F G R 7 0

. 1 2 5 n ot av ai l a bl e 0

. 0 08 0. 11 9

U S EP A Em is s i o n Fa c t o rs f o r C r ite r ia Polluta nts ( b oile rs > 1 0 0 M M B t u/hr he a t input) 3, 4 : 0. 07 1 0

. 0 1 4 0. 03 6 0

. 3 9 3 0. 09 8 0

. 0 0 2 0. 08 2 0

. 0 0 0

0. 17 1 0

. 0 1 4 0. 03 6 0

. 3 9 3 0. 18 6 0

. 0 0 2 0. 08 2 0

. 0 0 0

1) A d v a n c e d A i r C o ns u l t a nt s , Mur r a y v i l l e , G A
2 ) E m i s s i on s d a t a h ave b e e n es t i m a t e d u s i n g t h e t e s t r e s u l t s f r om A d van c e d A i r C o n s u l t a n t s an d E N E R A C 3 0 0 0 E t e s t i n g

. 3) U S E P A F i ft h E d i t i o n 1995

, w i t h S u ppl e m e n t s : A( 1 996 )

, B ( 19 96)

, D ( 199 8)

, a n d E ( 1 9 98) 4) T h e U G A N o

. 2 B o i l e r O p e r a t i ng P e r m i ti s ba s e d upo n a 1 30 MM B t u/ h r h e a ti n p u t

. 5 ) S O 2 em i s s i on s d a t a h ave b een r e v i ew e d i n r e p o rtS e c t i o n 5

. 5

, D i scu ssi o n

. 6) A l l bl e n d e d f u e l s c o ns i s t of 3 3 % bi of u e l a nd 67% N o

. 2 f u e l o i l

. 7) T h e F G R s y s t e m w a s l i m i t e d t o 7% - 10 % f l ue g a s r e c i r c u l a t io n , s e e r e po rtS e c t i o n 3

. 4. 

### Tab le 5 , C o m p ar i s o n o f U G A T est E m i ssi on s to U S E P A C r iter i a P o l l u t an t E m i ssi on Factors

Fu e l & Fi r i n g C o n d i t i o n

N o

. 2 Fu e l Oi l f i r e d

, u n c o n t r o lle d (w /o L N B o r FGR ) N a tu r a l Ga s f i r e d

, u n c o n t r o ll e d ( w /o L N B o r F G R ) N o

. 2 Fu e l Oi l f i r e d

, c o n t r o lle d w i th FGR N a tu r a l Ga s f i r e d

, c o n t r o ll e d w i th F G R



## Additional research is needed to understand:

1. Wh at is the effect of biofuel/fuel oil blend proportions on viscosity and m i scibility? Wh at blend proportions m a intain fluidity (low viscosity) over the range of am bient storage tem p eratures (say, 32 to 100 ° F.) typical in industrial applications? Wh at is the m i nim u m am ount of agitation required?

2. 

## Wh at are m i nim u m required specifications for fats and greases used as biofuel? Wh at are the requirem e nts for solids rem oval (screening), MIU (m oisture, insolubles, unsaponifiables), Ultim ate analysis (C, H, N, S), energy content, specific gravity, viscosity, etc.? How shall biof uels be specif i ed f o r environm ental perm itting?

6 - 2

## 7. REFERENCES

1. Miller, G., Badger, M., Larsen, J., Clem ens, T., Moyer, D., W e hr, T., 1999. A dem onstration of pig lard as an industrial boiler fuel; presented at the 24 th 

## International Conf erence on Coal Utilization & Fuel System s, Clearwater, FL.

2. Pearl, G., April 2001. Turn up the heat, Render (18-21)

.
3. Shigehara, R. T., Neulicht, R. M., Sm ith, W

. S., Peeler, J. W

. , Summ a ry of F Factor Methods for Determ ining Em issions from Com bustion Sources

.

4. Goodrum , J. W ., Geller, D. P., Adam s, T. T., 2002. The rheological characterization of anim al fats and their m i xtures with #2 fuel oil

. The University of Georgia, Athens, GA. Unpublished results.

5. The Babcock & W ilcox Com p any, 1976. Steam/ Its Generation and Use , 39 th 

## edition., Babcock & W ilcox, New York, NY

6. Energy Efficiency System s, Inc., description of the ENERAC 3000.

7. Advanced Air Consultants, Inc., 2002. Air em issions report for boiler num ber 2, anim al fats engineering trials at UGA steam plant, Athens, GA, January 30 – March 15, 2002.

8. Georgia Departm e nt of Natural Resour ces,, Environm ental Protection Division, Air Protection Branch, Part 70 Operating Perm it, GA Environm ental Protection Division Perm it No. 8221-059-0059-V-01-0, for The University of Georgia, Oct. 30, 2000.

9. Agrawal, R. K., W ood, S. C., 2002. Innovative solutions for cost-effective NOx control, Pollution Engineering; 34(6): 18-25.

10. Georgia Departm e nt of Natural Resour ces, Environm ental Protection Division, Air Protection Branch, Rules for Air Quality Control Chapter 391-3-1, effective Decem ber 26, 2001.

11. U. S. Environm ental Protection Agency, 1998. Em ission Factors.

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