一种用于二维稳态固定床的通用计算方法

摘要

Fixed-bed reactor is the most widely used reactor in the chemical process.However,the programming for solving its mathematical model has been case by case via solving partial differential equations till now.In such a situation,it is impossible to build up a complete calculation module for the fixed-bed reactor model and incur the workload and burden in simulation.In this work, a general method to obtain the distribution of temperature and concentration of fixed-bed reactor at steady state is proposed.The method makes use of mole fractions of key components as variables and then applies orthogonal collocation to solve the formula of partial differential equations,which is deduced in the material and heat balance.Molar flow rate of reaction mixture is introduced at the same time and the relationship between the instantaneous molar flow rate,the initial value and mole fraction of key components are also built with a variable transfer method,to make the solution have versatility.Therefore,the computing module,which is used to solve partial differential equations,becomes programmable independent of a specific reaction,i.e.,a common program module.For a specific reaction,only a kinetic equation program is required to be added into the module.%针对固定床反应器模拟过程难以形成其模型完整通用的计算模块且编程工作量大的问题，提出了一种稳态下固定床反应器中反应物和产物温度及浓度分布的通用计算方法。该方法以关键组分的摩尔分数作为变量，推导出关键组分在物料与热量衡算中的偏微分方程组中的通式，并利用正交配置法求解。同时考虑固定床反应器内气相流速的变化，将其描述为关键组分摩尔分数的函数进一步实现模型的通用性。对于特定的反应，只需提供目标反应的动力学方程及操作条件即可求解。最后利用所提出的方法实现乙苯催化脱氢制苯乙烯与乙炔法制氯乙烯反应过程的模拟，结果表明该方法具有通用性和高效性。