Nonequilibrium stage model is a significant improvement in multicomponent separation process simulation,but more equations are involved and the solution of the model equations,which relies on an adequate initial guess...Nonequilibrium stage model is a significant improvement in multicomponent separation process simulation,but more equations are involved and the solution of the model equations,which relies on an adequate initial guess for convergence of the Newton method,is difficult.In this work,based on the concept of pseudo-transient continuation approach,we proposed a new pseudo-transient(PT)nonequilibrium method.The proposed method decouples the strongly coupled model equations by introducing dynamic equations for material and energy conservation,as well as transition equations.Thus,the steady-state solution of the nonequilibrium stage model can be obtained through a robust and fast integration process,and the initial guess issue in Newton method can be effectively avoided.Two simulation cases were used to demonstrate the advantages and applicability of the proposed PT nonequilibrium method.展开更多
A nonequilibrium stage model was used to simulate countercurrent multicomponent catalytic distillation processes for methyl acetate hydrolysis. Computations of stage efficiencies or height equivalent to a theoretical ...A nonequilibrium stage model was used to simulate countercurrent multicomponent catalytic distillation processes for methyl acetate hydrolysis. Computations of stage efficiencies or height equivalent to a theoretical plate (HETP) were entirely avoided by this model. The consistency of simulated results and experimental data in conversions and concentration of each component along a column indicates that the model predicts the actual process well. The influences of operating parameters on hydrolytic conversions, such as feed molar ratios, feed locations, feed and reflux rates, heights of reactive and stripping sections, were analyzed adequately by simulating calculations. A good operating mode was then obtained, which is helpful to the development of a new process.展开更多
基金supported by the National Natural Science Foundation of China(21978203).
文摘Nonequilibrium stage model is a significant improvement in multicomponent separation process simulation,but more equations are involved and the solution of the model equations,which relies on an adequate initial guess for convergence of the Newton method,is difficult.In this work,based on the concept of pseudo-transient continuation approach,we proposed a new pseudo-transient(PT)nonequilibrium method.The proposed method decouples the strongly coupled model equations by introducing dynamic equations for material and energy conservation,as well as transition equations.Thus,the steady-state solution of the nonequilibrium stage model can be obtained through a robust and fast integration process,and the initial guess issue in Newton method can be effectively avoided.Two simulation cases were used to demonstrate the advantages and applicability of the proposed PT nonequilibrium method.
文摘A nonequilibrium stage model was used to simulate countercurrent multicomponent catalytic distillation processes for methyl acetate hydrolysis. Computations of stage efficiencies or height equivalent to a theoretical plate (HETP) were entirely avoided by this model. The consistency of simulated results and experimental data in conversions and concentration of each component along a column indicates that the model predicts the actual process well. The influences of operating parameters on hydrolytic conversions, such as feed molar ratios, feed locations, feed and reflux rates, heights of reactive and stripping sections, were analyzed adequately by simulating calculations. A good operating mode was then obtained, which is helpful to the development of a new process.
