(609c) IC Engine Performance and Emissions Operating On Landfill Gas and Synthesis Gas

In the United States, the decomposition of MSW in landfills emits a total of 7.2 billion m³ of methane a year. As CH₄ is over 20 times as potent a greenhouse gas as CO₂, capturing and exploiting its energy content has been a point of interest for several decades. The CH₄ emitted from landfills is mixed with an equal volume on average of CO₂. The presence of CO₂ detracts from using this landfill gas (LFG) as a fuel, as it decreases engine performance and increases pollutant emissions. Through dry reformation of LFG over a Rh/Al₂O₃ catalyst, synthesis gas (H₂/CO, SG) can be made in situ. A 5% addition of SG to LFG has been shown to reduce NO_x, CO, and unburned hydrocarbons (UHC) emissions by 40, 70, and 80 percent, respectively, and increase engine efficiency by 7 percent. NO_x, CO, and UHC emissions data and thermal efficiencies from combustion in a Honda GC 160E-QHA engine will be presented as a function of synthesis gas percentage (<5% to maximum SG capacity) in 50/50 v.% CH₄/CO₂ LFG; equivalence ratio; and power load (0.2 to 2 kW). Other gases such as H₂S are often found in trace amounts in LFG. SO_x emissions due to the introduction of trace H₂S (<0.5% by v.) to the simulated LFG will also be presented.