Stoichiometric Operation of a Gas Engine Utilizing Synthesis Gas and EGR for NOx Control

Abstract

This paper presents the results from an internal research study conducted at the Southwest Research Institute (SwRI) on the effects of stoichiometric mixtures of natural gas and synthesis gas with exhaust gas recirculation (EGR) on engine performance and exhaust emissions. Constant load performance and emissions tests were conducted on a modified, single-cylinder, Caterpillar 1Y540 research engine at 11.0 bar (160 psi) bmep. Engine performance and emissions comparisons between natural gas with EGR, and natural gas with syngas and EGR are presented. In addition, the performance characteristics of the fuel reforming catalyst are presented. Results show that thermal efficiency increases with increasing EGR for both natural gas operation and natural gas with syngas operation at constant load. The use of syngas with natural gas extended the EGR tolerance by 44.4 percent on a mass basis compared to natural gas only, leading to a 77 percent reduction in raw NOx emissions over the lowest natural gas with EGR NOx emissions. [S0742-4795(00)00504-4]

A comparison of the emission and impingement heat transfer of LPG–H2 and CH4–H2 premixed flames

“…Shresta and Karim [8] pointed out that burning a typical hydrocarbon fuel together with hydrogen leads to a reduction in CO and NO x emissions. Similar decrease in NO x emission has been reported in [9,10]. Other benefits of hydrogen addition to natural gas-fueled spark-ignition engines can be found in [11e13].…”

Characterization of the effects of hydrogen addition in premixed methane/air flames

“…As a consequence, the proportion of end gas recirculation (EGR) accepted by the engine can be increased [12] and NO x emissions are decreased [12][13][14]. Hydrogen addition is also interesting for HCCI engines (homogeneous charge compression ignition) [15][16][17].…”

Natural gas spark ignition engine efficiency and NOx emission improvement using extreme exhaust gas recirculation enabled by partial reforming

“…Blending gasoline with 30 per cent partial oxidation reforming products reduced NO x emissions by between 55 and 85 per cent by increasing the EGR limit. Smith and Bartley [27] reported the EGR tolerance enhancement of an NG SI engine to be 44 per cent more than the baseline case. They utilized the synthesis gas in the EGR system by using a partial oxidation CH 4 catalyst.…”