Methane Emission Reduction Technologies for Natural Gas Engines: A Review

• Published in: Energies (Basel) Vol. 16; no. 20; p. 7054
• Main Authors: Huonder, Andrew, Olsen, Daniel
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.10.2023
• Subjects: Air pollution; Air quality management; Carbon dioxide; catalytic oxidation; Emission standards; Emissions; Emissions (Pollution); Energy consumption; Engines; Greenhouse gases; Hydrocarbons; Hydrogen; hydrogen blending; Inflation Reduction Act 2022-US; Internal combustion engines; Laws, regulations and rules; Methane; methane emissions; Natural gas; natural gas engines; Piston rings; Power; regenerative thermal oxidation; Reporting requirements; Stroke; Valves; VOCs; Volatile organic compounds; United States > US
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en16207054

This review summarizes technologies to reduce methane emissions from natural gas engines with a focus on exhaust treatment. As regulations on methane emissions from natural gas facilities become more restrictive, methane emission reduction technologies become increasingly important. Methane is the second most prevalent human-generated greenhouse gas. In 2020, 197,000 metric tons of methane were released as a result of methane slip. In-cylinder methods such as optimized valve timing and crevice volume reduction are effective in reducing methane slip. Exhaust treatment methods such as catalytic oxidizers and regenerative thermal oxidizers can achieve near 100% methane reduction under certain conditions. Implementation of hydrogen blending and exhaust gas recirculation systems results in a decrease in methane emissions of between 20 and 30%. Future research should focus on testing full-scale catalytic oxidation systems on lean-burn natural gas engines. Research should also focus on implementing regenerative thermal oxidizers on natural gas engines, as well as combining hydrogen blending with these techniques.