CO2/CH4 Conversion to synthesis gas (CO/H2) in an internal combustion engine

We investigate a species and energy conversion process applied in an internal combustion engine. CO2 and CH4 is converted to synthesis gas (CO and H-2). This reaction is endothermic and in addition requires high temperatures. The temperature is increased via compression and a parallel exothermic reaction. We investigate this process with the aim of obtaining dependencies of the initial conditions on the CO2 conversion, as well as finding optimal conditions under which CO2 is converted and mechanical work is delivered. The dependencies of the initial conditions are investigated using two methods, a) a large parametric study; b) optimal conditions are found using a genetic algorithm that optimizes the CO2 conversion as target function. It was found that the gas mixture composition has the largest influence on the CO2 conversion, if there is a parallel partial oxidation of CH4 and DME (as a reaction enhancer) to CO and H-2. During the investigations, we found initial conditions in which up to 55% of the initial CO2 was converted, in combination with work output. The best results were found for fuel-rich conditions (phi = 2.5 to 3.5); argon concentration, heat losses and initial temperature showed a minor influence. We found that ignition must occur to reach the high temperatures required to convert large amounts of CO2. A suitable choice of the initial gas, CO2 is converted throughout the entire process, despite the (partial) oxidation of the fuel. (c) 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.