ABSTRACT: FAME of lard, beef tallow, and chicken fat were prepared by base-catalyzed transesterification for use as biodiesel fuels. Selected fuel properties of the neat fat-derived methyl es- ters (B100) were determined and found to meet ASTM specifica- tions. The cold-flow properties, lubricity, and oxidative stability of the B100 fat-derived fuels also were measured. In general, the cold-flow properties of the fat-based fuels were less desirable than those of soy-based biodiesel, but the lubricity and oxidative sta- bility of the fat-based biodiesels were comparable to or better than soy-based biodiesel. Nitrogen oxide (NO x ) emission tests also were conducted with the animal fat-derived esters and com- pared with soybean oil biodiesel as 20 vol% blends (B20) in pe- troleum diesel. The data indicated that the three animal fat-based B20 fuels had lower NO x emission levels (3.2–6.2%) than did the soy-based B20 fuel. Paper no. J11054 in JAOCS 82, 585–591 (August 2005). KEY WORDS: Alkyl ester, biodiesel, chicken fat, cloud point, cold filter plugging point, high-frequency reciprocating rig, lard, NO x emissions, oxidation stability, tallow. The use of fats and oils as diesel engine fuels has been recog- nized since the advent of the diesel engine. Because of their high viscosities, however, it is now thought best to convert nat- ural fats and oils into their simple alkyl ester derivatives to im- prove their viability as replacements for petroleum diesel fuel (1–4). This conversion is usually accomplished by alkali-cat- alyzed transesterification of the oil or fat with a simple alcohol, typically methanol, which converts their TAG into the corre- sponding simple FA alkyl ester derivatives. The success of transesterification depends on several factors, including the type of catalyst used, the mole ratio of alcohol to TAG used, the FFA content of the oil or fat, the water content, the reaction time (5), and mixing (6). The term “biodiesel” is now gener- ally applied to these renewable alternative fuels when made from vegetable oils, animal fats, or recycled greases such as restaurant grease. In the United States, soybean oil methyl es- ters are the most common biodiesel fuel produced. There is a growing interest in the use of biodiesel fuels since biodiesel offers several fuel advantages over petroleum diesel, including improved lubricity, a higher flash point, lower toxic- ity, biodegradability, and no net contribution to the greenhouse effect because it is made from renewable resources. Also, the increased use of these alternative fuels not only helps in our ef- forts to decrease dependency on foreign oil but also provides for a cleaner environment. Experimental data have shown that the addition of biodiesel to diesel fuel reduces particulate and carbon monoxide emissions but increases nitrogen oxide (NO x ) emissions (7,8). Pure soy biodiesel (B100) increases NO x emis- sions by approximately 12% when compared with NO x emis- sion data for petroleum diesel. At the more widely used 20% blend level of biodiesel in petrodiesel, however, the increase in NO x emissions is only on the order of 2–4%. With increasingly strict environmental regulations, even this relatively small in- crease in NO x can negatively impact the use of biodiesel. Therefore, it may be of benefit to identify other feedstocks for producing a biodiesel that could improve NO x emissions when blended with petroleum diesel. Chicken fat, lard, and tallow are relatively inexpensive co- products of their respective industries, yet only tallow is used in significant amounts in nonfood applications. These materi- als are readily available and can be suitable feedstocks for con- version to biodiesel. A major drawback of animal fat-based biodiesel, however, is that it generally has poorer cold-temper- ature properties than does vegetable oil-based biodiesel (9–12). Nevertheless, it is possible to improve the cold-flow properties of the esters through dry fractionation of the fat before esterifi- cation (13). This study was intended to compare the fuel and NO x emis- sion levels of biodiesel produced from animal fats with exist- ing data for soy biodiesel. Cold-temperature properties and other selected properties such as lubricity of the animal fat- derived biodiesel fuels also were compared with soy biodiesel and petroleum diesel. MATERIALS AND METHODS Materials. Edible beef tallow, refined lard, and rendered chicken fat were obtained from HRR Enterprises (La Porte, IN), Holsum Foods (Albert Lea, MN), and Tyson Foods (Springdale, AR), respectively. Certified diesel fuel was ob- tained from Chevron Phillips Chemical Company (Houston, Copyright © 2005 by AOCS Press 585 JAOCS, Vol. 82, no. 8 (2005) *To whom correspondence should be addressed at U.S. Department of Agri- culture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Ln., Wyndmoor, PA 19038. E-mail: vwyatt@errc.ars.usda.gov Fuel Properties and Nitrogen Oxide Emission Levels of Biodiesel Produced from Animal Fats Victor T. Wyatt a, *, Melissa A. Hess a , Robert O. Dunn b , Thomas A. Foglia a , Michael J. Haas a , and William N. Marmer a a United States Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038, and b United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, Illinois 61604