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

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.