Reducing emission of methane through advanced radical kinetics and adaptive burning in large engines (REMARKABLE)

Project summary:

This project seeks to reduce methane emissions from 2-stroke larger-bore compressor-station natural gas (NG) engines by improving lean-burn operation, thereby reducing exhaust methane emissions, maintaining low-criteria pollutant emissions, and reducing exhaust CO2 emissions. The project team will accomplish this through a two-fold implementation of technological advances, which include: 1) nanosecond non-thermal plasma-based ignition system capable of generating highly re-active intermediate species that result in rapid self-sustaining combustion, and 2) a predictive feed-forward cyclic combustion control strategy that predicts and mitigates partial-fire and misfire cycles. This concept succeeds in reducing methane emissions in several ways. First, non-thermal plasma discharges generate highly reactive intermediate species (e.g., methyl, peroxide, and ozone), enabling successful ignition and rapid burn of leaner fuel-air mixtures than other ignition sources (e.g., conventional spark ignition, SI). Second, plasma-based ignition systems provide consistently robust ignition of fuel-air mixtures from cycle to cycle, relative to conventional SI systems. Third, the proposed concept leverages a model-based, feedforward cyclic combustion control strategy that predicts the onset of misfire or partial-fire and correspondingly implements an intervening control scheme to avoid misfire or partial-fire, thus further substantially reducing engine exhaust methane emissions. The ultimate outcome of this work is to demonstrate a working, field-test validated, prototype plasma-ignition system and a model-based feedforward combustion control system that would be a disruptive and transformative technology for large NG engines with potential for large-scale market adoption.