Reduction of Methane Emissions from Natural Gas Integral Compressor Engines through Fuel Injection Control

Abstract

Methane emissions from over 7000 large-bore natural gas engines used for gas compression in the United States result from combustion inefficiency and the escape of unburned methane through the crevices. Methane is a strong greenhouse gas with a warming potential 28 times that of carbon dioxide. The Inflation Reduction Act passed by the Biden administration in 2022 imposes a methane “waste” fee that accumulates yearly to invest in clean energy and climate action starting in 2024. This study aims to reduce the amount of methane emissions from large bore engines through fuel injection techniques, thereby advancing sustainable energy development. The strategies explored investigate fuel injection pressure and timing optimization, crankcase methane emissions quantification and mitigation, and ring-pack methane quantification. While varying injection pressures and injection timing on the engine, the performance and methane emission characteristics were measured. Also, a model of the engine was created for computational fluid dynamics (CFD) simulations using CONVERGE Studio v 3.0. Experimental results showed that methane emissions are minimized with late-cycle fuel injection at 500 psi and 100 degrees BTDC. Computational results showed that the ring pack contributes up to 34% of methane emissions in the large bore engine model.