基于热力学分析的甲烷干重整反应积炭抑制策略及反应条件优化OA

Dry reforming of methane(DRM)can convert greenhouse gases CH4 and CO2 into high-value syngas,with dual benefits of environmental mitigation and energy upgrading.However,this reaction usually needs to be carried out above 700℃,leading to high energy consumption and catalyst deactivation due to metal sintering and carbon deposit.The equilibrium compositions in the DRM system were systematically evaluated based on thermodynamic analysis,and the effects of reaction temperatures,inert gas contents,reaction pressures and feed ratios of raw gas(n(CH4):n(CO2))on the catalytic performances and carbon deposit behaviors of catalysts were discussed.The deviations between actual reaction results reported in the literature and the theoretical equilibrium predictions were also thoroughly analyzed.The results show that reducing n(CH4):n(CO2)to 1:2 can lower the complete conversion temperature by 200℃and effectively suppress carbon deposit formation at above 700 ℃.In addition,changing the inert gas dilution ratio n(CH4):n(CO2):n(inert gas)to 1:1:2 can remarkably suppress carbon deposit from 500℃to 800℃.However,high-pressure operations suitable for the industrial applications are not conducive to raw material conversion and can promote carbon deposit.It is more reasonable to evaluate the actual reaction results in the low-temperature zone(<600℃)and high-temperature zone(>800℃)using the no carbon deposit formation model,while the actual reaction results from 600℃to 800℃need to be evaluated in conjunction with the carbon deposit equilibrium model.This research clearly defines the operational boundaries and suppression strategies of carbon deposit for DRM based on thermodynamic analysis,in order to provide an essential theoretical basis for catalyst design and catalytic performance evaluation and optimization.