Optimization of operating conditions of an internal combustion engine used as chemical reactor for methane reforming using ozone as an additive

Internal combustion engines can be used as chemical reactors exploiting the high temperature and pressure as well as short residence time for chemical conversion. For instance, methane and CO${}_2$ can be efficiently converted to H${}_2$ and CO (syngas). The process can be boosted by additives such as dimethyl ether (DME). In this paper, the focus is on optimizing the operating conditions for the use of ozone, O${}_3$, as an alternative fuel additive for dry reforming of methane. Furthermore, methane can be converted to C${}_2$ hydrocarbons, which is also studied numerically to find optimized operating conditions, again using O${}_3$ as an additive. The engine is modelled as a single-zone batch reactor under ideal gas assumptions with a variable volume profile. An elementary-step reaction mechanism consisting of 749 reactions among 132 species and including O${}_3$ chemistry was used for the simulations. CO${}_2$ conversion of over 70% is possible using O${}_3$ as an additive, whereas the maximum achievable using DME was around 50%. The optimized yield of C${}_2$H${}_4$ is higher with O${}_3$ as an additive as compared to DME, at all the inlet gas temperatures, whereas it is lower for CH${}_2$O and comparable for C${}_6$H${}_6$ and CH${}_3$OH.