Improving performances of a lean burn cogeneration biogas engine equipped with combustion prechambers

Test of the unscavenged prechamber ignition system on a 150kW cogeneration engine fed with biogas are presented. The objective was to reach at least 36% in fuel conversion efficiency with exhaust gas emissions lower than the Swiss regulations limits (NOx, CO: 400 and 650mg/Nm3, 5% O2 and 0% relative humidity) without exhaust gas after-treatment. With a compression ratio of 12.0, it is shown that 40% of CO2 induces a CO reduction of 15% and an HC reduction of 8% for the same NOx emissions but with a slight reduction of 1% in fuel conversion efficiency compared to pure natural gas. The results for the compression ratio of 13.3, a spark timing of 8 caBTDC, an air factor ?l of 1.57 and 39,5% CO2 are a fuel conversion efficiency of 37.7% while keeping the NOx and CO emissions below the Swiss limit. This study shows that using unscavenged prechambers in biogas engines is particularly beneficial to reach interesting conversion efficiencies with low emissions. It allows a significant boost in energy conversion from biogas compared to existing systems.

[1]  R. J. Crookes,et al.  Spark-ignition engine performance with simulated biogas : a comparison with gasoline and natural gas , 1998 .

[2]  G. P. Mueller.  Landfill Gas Application Development of the Caterpillar G3600 Spark-Ignited Gas Engine , 1995 .

[3]  Daniel Favrat,et al.  Investigation of the prechamber geometrical configuration of a natural gas spark ignition engine for cogeneration: part. I, numerical simulation , 2003 .

[4]  K. C. Midkiff,et al.  Fuel Composition Effects on Emissions From a Spark-Ignited Engine Operated on Simulated Biogases , 2001 .

[5]  Daniel Favrat,et al.  Comparison between direct and indirect (prechamber) spark ignition in the case of a cogeneration natural gas engine, part II : engine operating parameters and turbocharger characteristics , 2002 .

[6]  R. J. Crookes,et al.  Assessment of simulated biogas as a fuel for the spark ignition engine , 1998 .

[7]  M. A. Goossens,et al.  Landfill gas power plants , 1996 .

[8]  Konstantinos Boulouchos,et al.  Natural Gas Engines for Cogeneration: Highest Efficiency and Near-Zero-Emissions through Turbocharging, EGR and 3-Way Catalytic Converter , 2000 .

[9]  R. D. Richardson,et al.  Operation of a Caterpillar 3516 spark-ignited engine on low-Btu fuel , 1987 .

[10]  Daniel Favrat,et al.  Lean-Burn Cogeneration Biogas Engine with Unscavenged Combustion Prechamber: Comparison with Natural Gas , 2002 .

[11]  Fokion N. Egolfopoulos,et al.  FUNDAMENTAL AND ENVIRONMENTAL ASPECTS OF LANDFILL GAS UTILIZATION FOR POWER GENERATION , 2001 .

[12]  John K. S. Wong,et al.  Study of Mixtures of Methane and Carbon Dioxide as Fuels in a Single Cylinder Engine (CLR) , 1977 .

[13]  G. Karim,et al.  Predicting the effects of the presence of diluents with methane on spark ignition engine performance , 2001 .

[14]  Daniel Favrat,et al.  Comparison between direct and indirect (prechamber) spark ignition in the case of a cogeneration natural gas engine, part I: engine geometrical parameters , 2002 .