Dynamic Simulation Of Acetonitrile Plant

Acetonitrile is an important organic intermediate and is a by-product of the ammoxidation of propylene to acrylonitrile.The crude acetonitrile from the upstream contains a large amount of water and impurities such as hydrocyanic acid and oxazole,and the purity of the product is ensured in the industry through a continuous recycling process.Since the acetonitrile-water system is azeotropic,separation of components is often achieved by means of extractive distillation and pressure swing distillation.Since the pressure swing distillation method does not introduce an extractant,the energy consumption problem can be optimized by the heat integration method,and it is widely used in industrial production.The paper selected a petrochemical company's 5500t/a acetonitrile continuous recovery process and conducted a series of studies.The steady-state simulation was carried out in Aspen Plus software,and the selection and convergence strategy of thermodynamic methods were analyzed.The effects of the reflux ratio of the dehydrogenation cyanide column on the cumulative oxazole content were discussed.The liquid extraction position and flow rate of the improved solution were analyzed.The effect of the reflux ratio of dehydrocyanate column on the content of hydrocyanic acid in the sideline products is discussed,and a countermeasure method is proposed for the problem of high hydrocyanic acid content in the system.Depending on the Aspen Dynamics platform,different dynamic control schemes were designed.The improved measures were proposed for the shortage of the original control scheme,which can cope with a certain degree of feed flow disturbance.Based on the DSO platform of Beijing University of Chemical Technology,an accurate equipment model through C language programming calculation was built,and a chemical dynamic simulation system for a plant's acetonitrile plant was developed.The system can simulate the normal opening and stopping process of the device and the emergency handling process of the accident,which can be used for operator training.