The Optimization Of Process Simulation And Control Scheme On Isobutylbenzene Separation

There are many problems existing in the process of batch distillation for isobutylbenzene, such as high consumption of cooling water and steam, low level of automation with more labour and so on. To solve these problems, the technology of continuous distillation process was applied for separation of the synthetic fluid coming from isobutylbenzene synthesis process. Steady-state simulation for the separation was performed with the software of Aspen Plus and the optimization of control scheme was achieved on the basis of the obtained process parameters.Firstly, the composition of synthetic fluid was analyzed, and at the same time the properties, applications and stability of all the components in the synthetic fluid were studied. The simulation process was appropriately simplified by using a main component instead of the complicated components. The continuous distillation separation process based on the separation rules and the property of the main components was determined.Secondly, the steady-state simulation of total separation process with three columns for isobutylbenzene was achieved and the parameters of separation process were obtained with the "heuristic" optimization algorithm. Among the columns, the theoretical tray number of4-methyl-l-pentene recovery column (T01) is24and reflux ratio is1.68; Toluene recovery column (T02) is22and reflux ratio is0.6; Isobutylbenzene recovery column (T03) is112and reflux ratio is4.77. Product results:the purity of isobutylbenzene is up to mass fraction of99.99%and recovery rate is as high as99.9%, both impurity contents of toluene and n-butyl benzene are all50ppm or less; The mass fraction of4-methyl-1-pentene is99.8%or higher purity and recovery rate is98%; The purity of toluene is as high as99.6%and n-butyl benzene is99.8%.Finally, the parameters of auxiliary equipments were set and the initial control scheme of the total separation process for isobutylbenzene was chosen on the basis of accurate steady-state simulation. The dynamic performance of the process and the control structure were analyzed by investigating the dynamic response under the disturbance of the initial control scheme. It is the appropriate complex control strategy like cascade control, dual-temperature control to improve the control quality and control precision. The whole control scheme was optimized with the dynamic simulation software Aspen Dynamics. In order to meet the requirements of product quality, purity and yield, the analysis and adjustment based on the optimized control scheme of disturbance response. The control strategy was included to improve the control structure, so that the ultimate control scheme of separation process for isobutylbenzene with continuous distillation was determined.The results in this paper with a certainly reference value to reform isobutylbenzene continuous separation process and improve the automation level in the control system can be used to improve the isobutylbenzene separation process.