The Whole Process Simulation Of An Acrylonitrile Plant By Propylene Ammoxidation Sohio Technology

Acrylonitrile is a basic organic chemical product,and it is an important raw material for synthetic fibers,synthetic resins,rubber,dyes,pharmaceuticals and other industries.Based on the Sohio process,a simulation study on the ammoxidation of propylene to acrylonitrile was carried out.The Sohio process for the synthesis of acrylonitrile includes major production units such as reaction,quench absorption,refining,multi-effect evaporation,ammonium sulfate,compressors,and utilities.Based on the DSO dynamic simulation software platform which is developed by Beijing University of Chemical Technology independently,through the analysis of the equipment,the corresponding mathematical model was established,the whole process pipeline network topology was build up,and the NRTL thermodynamic model was chosen,the sequential modular method was adopted as the solution strategy,and the explicit Euler method was used to solve the equations.The whole process dynamic simulation was completed by using C++language programming.The simulation results are in good agreement with the production data,which shows that the established dynamic model is reliable.The dynamic characteristics of the recovery tower and the hydrocyanic acid tower in the refining unit were analyzed by the established dynamic model,the variation of operation parameters of two towers with time under disturbance of feeding conditions was obtained.A complete simulation training software for the whole process of acrylonitrile plant was developed,which has many functions,such as device start-up and shutdown,interlocking,alarm,accident training,scoring and so on.The software can be used for the operation training of enterprise employees,the operation research of dynamic process and the optimization of system parameters.Two energy-saving improvement schemes for the original process were proposed and simulated with Aspen Plus.In the first scheme,reaction gas was used as multi-effect evaporation heat source instead of steam,which can save a lot of steam.In the second scheme,reaction gas waste heat was used to generate low pressure steam,which can produce 8.15t/h low pressure steam of 0.4MpaG.