Proceedings available at: http://www.extension.org/67668
The purpose of this research is to review engine performance and technology issues relating to generating electricity from digester gas in reciprocating internal combustion engines. Research performed at the Colorado State University (CSU) Engines & Energy Conversion Laboratory (EECL) and published material from other organizations is utilized.
Digester gas (digas) can be used effectively in internal combustion engines for electricity production to offset operating costs and/or sell to the electric utility. Stationary industrial engines are generally employed for this purpose. Four application areas where systems have been successfully demonstrated are sewage processing plants, animal waste facilities, landfills, and agricultural waste processing systems. Digas is generated through anaerobic digestion, or biomethanization, for all these cases. There are many common engine technical issues within these areas, although the digas generation systems employed in each case are different. In this presentation issues pertinent to running engines on digas are explored. The focus is on animal waste facilities, but the presentation draws upon the other application areas for technical insight related to engine technology. Specific stationary engine types are discussed. High engine efficiency and power density are important to the economic viability of anaerobic digestion systems. Engine operational and design changes to maintain high efficiency and power density for digas fueling are analyzed. Management of engine maintenance problems is also key to economic viability. Corrosive gases contained in digas, such as hydrogen sulfide (H2S), are evaluated.