Title : Auto thermal reforming of biogas to syngas: Thermodynamic optimization for low CO2 emissions
The innovative utilization of renewable energy sources, such as biogas, with relatively low carbon emission have drawn increasing attention. Biogas is a mixture of mainly methane and carbon dioxide that is produced by the anaerobic digestion of residual biomass. Biogas reforming can convert two greenhouse gases to valuable syngas, which is beneficial to environment protection. However, the multiple components in biogas remain a big problem in the selection of biogas reforming technology and parameters. The effects of components besides CH4 and CO2, such as O2, have not been sufficiently studied on biogas reforming. The process of combining dry and partial oxidative reforming of methane, also known as auto-thermal reforming of methane, have been reported to be effective in compensating energy consumption of dry reforming and adjusting the H2/CO ratio of syngas.
This paper, we focus on the thermodynamic optimization of biogas auto-reforming process with various operations conditions (gas components, temperature, and pressure). A minimum Gibbs free energy method and economic-technical analysis method based on Aspen-Plus was applied to modeling the biogas auto-thermal reforming process, with the optimization of biogas conversions, selectivity, energy consumption, and CO2 emissions. Results show that carbon deposition can be reduced by increasing O2 contents and reaction temperature. The auto-reforming of biogas stand for a good option for biogas utilization with minimum CO2 foot print.