Thermodynamic calculation of methane combined reforming to synthesis gas process based on Aspen Plus
The product synthetic gas compositions in methane combined reforming are governed by thermodynamic equilibrium and the relevant coke deposition reactions are also dependent on operation conditions.Hence,quantitative thermodynamic analysis of the influences of operation conditions(feedstock composition,temperature,pressure)on product compositions and coke formation reactions are desirable for process design.In this contribution,the RGibbs reactor in Aspen Plus software was used to calculate Gibbs free energies at varied temperatures,the influence of feeding compositions,temperature and pressure on the compositions of equilibrated reaction mixtures by taking into consideration all relevant reactions.Both methane and carbon dioxide conversions increased as a consequence of temperature increase or pressure decrease,as reflected by the endothermic nature of the volume expansion reaction.When stoichiometric feed[CH4∶(CO2+H2O)=1∶1]was adopted,the influence of different conditions on the composition of reaction products was explored by changing the reaction temperature,pressure and feed composition and the equilibrium conversion of CH4 and CO2 increased with increasing temperature and tended to the limit with increasing temperature for all stoichiometric ratios.Meanwhile,methane conversion increased and the carbon deposition increased with increasing carbon dioxide to methane ratios,while methane conversion elevation and suppression of carbon deposition could be achieved by increasing the proportion of steam,even under pressurized operations.The H2/CO ratios in the product syngas could be manipulated to meet the required low concentrations for unconverted methane.With respect to specified downstream use of syngas,to generated methanol,ethanal,acetic acid and Fischer-Tropsch synthesis,the optimized operation conditions was identified.These calculations provided a thermodynamic basis for selection of bi-reforming conditions,process and catalyst design.
thermodynamicsAspen Plusmethane combined reformingGibbs free energycarbon dioxidenatural gas
万方数据
维普
