Thermodynamical Analysis and Optimization of Dry Reforming and Trireforming of Greenhouse Gases: A Statistical...

The paper deals with thermodynamic analysis of CH₄ reforming with different oxidants (CO₂, H₂O, and O₂) in DRM and TRM processes. Both processes producing syngas use simultaneously two components of greenhouse gases as feedstock: CO₂ and CH₄. Statistical methods (Response Surface Methodology, Ridge Analysis) were used to analyze the effects of temperature, pressure, and molar ratio of oxidants to methane on feedstock conversion, yield and selectivity of products, H₂ and CO, and the H₂/CO ratio characterizing the suitability of syngas for various syntheses. The problem of the propensity of carbon deposition in the Dry Reforming of Methane (DRM) process through the selection of operational process conditions was minimized, and in the case of the TRM process was reduced completely. The Dry Reforming of Methane (DRM) process, which is a source of synthesis gas for the subsequent synthesis of long-chain hydrocarbons (H₂/CO = 1), is recommended to be carried out at high temperature (1273 K), low pressure (1 atm) with a molar ratio of CO₂/CH₄ in the feedstock of about 1. Increasing the proportion of CO₂ in the feedstock reduces the cooking of the catalyst but at the same time reduces the hydrogen yield. Additional oxidants (O₂, H₂O) introduced into the system define the TRM process and enable the production of synthesis gas with a composition suitable for methanol production (H₂/CO = 2). A positive effect on increasing the H/CO ratio is the addition of H₂O, which intensifies the WGS reaction in the system. Both oxidants (O₂, H₂O) protect to some extent against catalyst cooking, but at the same time reduce hydrogen yield and CO₂ conversion, as they are more reactive in the reaction with CH₄.