M.S. Thesis: A Study on Performance and Emissions of a 4-stroke IC Engine Operating on Landfill Gas with the Addition of H2, CO and Syngas
By Jechan Lee
Advisor: Dr. Marco J. Castaldi
Department of Earth and Environmental Engineering
Fu Foundation School of Engineering & Applied Science
Fossil fuels supply nearly 80% of world energy demand . Burning of fossil fuel always has associated with it emissions in the forms of nitrogen oxides (NOX), sulfur oxides (SOX), carbon monoxide (CO), unburned hydrocarbons (UHC). These emissions have environmental impacts that are both local and global. Moreover, in recent years, air quality has become a severe problem in many countries, and the interest to replace fossil fuels with renewable and sustainable energy sources has increased for reducing CO2 and methane emissions.
Landfill gas, a potential alternative energy source, is generated from anaerobic decomposition of municipal solid waste deposited in landfills. The main portion of landfill gas is mainly comprised of methane and carbon dioxide together with a smaller amount of oxygen and nitrogen and trace amounts of other gases as shown in Table 1.1. Methane is a highly potent greenhouse gas with a global warming effect almost 21 times greater than carbon dioxide when directly released into the atmosphere. Recently, landfill gas has attracted considerable interest as a source of alternative energy for generating heat, power or fuel with the benefit of reducing direct methane emission into the atmosphere, for example there have been about 450 LFGTE projects in the US . However, there are some disadvantages in the use of landfill gas: composition changes considerably depending on the landfill condition, season, and the type of waste, corrosiveness, lower heating value, high maintenance issues and capital costs. Due to these disadvantages, landfill gas is sometimes not considered as a good sustainable energy resource. Hence, in order to effectively utilize the landfill gas, these problems must be adequately addressed through appropriate engineering and technological approaches.
In this research, a small spark ignition engine was operated using pure methane, a simulated landfill gas, and the addition of hydrogen and carbon monoxide, and these various 9 fuels were compared in terms of the engine performance and emissions for the purpose of assessing the efficient utilization and direct application of landfill gas.