A Novel IC Engine Fueled by H2/CH4 Blends with High-Efficiency and Ultra-Low NOx Emissions for Prime Power Distributed Generation

The Issue

In-state gas-fired generation accounts for more than half of the power generation sector’s greenhouse gas (GHG) emissions in California. Decarbonization efforts, such as using H2 fuel blends, can be used to support California’s ambitious GHG emission reduction goals of carbon neutrality by 2045. However, as the blends of H2 reach high amounts exceeding 30 percent, the increasing NOx emissions and other criteria pollutants become a major concern. One of the major challenges for gas-fired engines is abating NOx to ultra-low levels, where the typical approach is to use over-sized urea Selective Catalytic Reduction systems. However, urea injection for small gas-fired applications is not a preferred path, as it adds complexity to an otherwise relatively simple unit. To get additional benefits, gas-fired generation can be combined with heat production in a combined heat and power (CHP) system. Traditionally, CHP systems are required to be more than 100 kW to be economically and environmentally viable, but they do not have an economic benefit without continuous high electrical and heat demand. Large engines are more efficient than small engines, and the CHP systems need to be highly efficient to have a return on investment. Also, small gas-fired engines cannot maintain their efficiency while mitigating the NOx emissions, which is typically a negative outcome of adding high blends of H2 to the methane (CH4) fuel stream.