The oxidative coupling of methane （OCM） to ethylene over a perovskite titanate catalyst in a fixed bed reactor was studied experimentally and numerically. The two-dimensional steady state model accounted for separat...The oxidative coupling of methane （OCM） to ethylene over a perovskite titanate catalyst in a fixed bed reactor was studied experimentally and numerically. The two-dimensional steady state model accounted for separate energy equations for the gas and solid phases coupled with an experimental kinetic model. A lumped kinetic model containing four main species CH4, O2, COx （CO2, CO）, and C2 （C2H4 and C2H6） was used with a plug flow reactor model as well. The results from the model agreed with the experimental data. The model was used to analyze the influence of temperature and feed gas composition on the conversion and selectivity of the reactor performance. The analytical results indicate that the conversion decreases, whereas, C2 selectivity increases by increasing gas hourly space velocity （GHSV） and the methane conversion also decreases by increasing the methane to oxygen ratio.展开更多
An initial differential mathematical model of the process of catalytic reactions coupled in a membrane reactor is developed.The "donor" reaction refers to one that produces the key substance that may permeat...An initial differential mathematical model of the process of catalytic reactions coupled in a membrane reactor is developed.The "donor" reaction refers to one that produces the key substance that may permeate the membrane and be consumed by the "acceptor" reaction.According to the maximum principle in mathematics,the analysis indicates that,in order to obtain maximum yield of the "acceptor" reaction,there should exist our optimal profile of the packed-bed catalytic activity on the "acceptor" reaction side of the membrane reactor,which is a one-time open-close function at the optimum position,as followsξ *(z)=0 ? (0<z<z r ) ξ max (z r ≤z≤1)where ξ *(z) is optimal function of catalytic activity, ξ max its maximum value, z the position,and z r the optimum position.The function means physically that catalytic activity equals to zero near the inlet and that,at the optimum position,activity should be kept maximum constant value on the "acceptor" reaction side.Finally the effect of membrane permeability on the optimum catalytic activity is also investigated.It is found that,as the membrane permeability increases,the optimum open-close position of optimal catalytic activity profile function will move closer to the inlet of the membrane reactor.展开更多
文摘The oxidative coupling of methane （OCM） to ethylene over a perovskite titanate catalyst in a fixed bed reactor was studied experimentally and numerically. The two-dimensional steady state model accounted for separate energy equations for the gas and solid phases coupled with an experimental kinetic model. A lumped kinetic model containing four main species CH4, O2, COx （CO2, CO）, and C2 （C2H4 and C2H6） was used with a plug flow reactor model as well. The results from the model agreed with the experimental data. The model was used to analyze the influence of temperature and feed gas composition on the conversion and selectivity of the reactor performance. The analytical results indicate that the conversion decreases, whereas, C2 selectivity increases by increasing gas hourly space velocity （GHSV） and the methane conversion also decreases by increasing the methane to oxygen ratio.
文摘An initial differential mathematical model of the process of catalytic reactions coupled in a membrane reactor is developed.The "donor" reaction refers to one that produces the key substance that may permeate the membrane and be consumed by the "acceptor" reaction.According to the maximum principle in mathematics,the analysis indicates that,in order to obtain maximum yield of the "acceptor" reaction,there should exist our optimal profile of the packed-bed catalytic activity on the "acceptor" reaction side of the membrane reactor,which is a one-time open-close function at the optimum position,as followsξ *(z)=0 ? (0<z<z r ) ξ max (z r ≤z≤1)where ξ *(z) is optimal function of catalytic activity, ξ max its maximum value, z the position,and z r the optimum position.The function means physically that catalytic activity equals to zero near the inlet and that,at the optimum position,activity should be kept maximum constant value on the "acceptor" reaction side.Finally the effect of membrane permeability on the optimum catalytic activity is also investigated.It is found that,as the membrane permeability increases,the optimum open-close position of optimal catalytic activity profile function will move closer to the inlet of the membrane reactor.
