Modeling Application And Optimization Research Of Separation System Cracking Device In First Chemical Plant

Affected by the factors such as composition and supply of raw materials, the cracking device in First Chemical Plant have some problems that the operation stability of separation system is lower, the loss rate of Ethylene and Propylene is higher, energy consumption of device is bigger. In order to solve the problems, the study adopting real-time operating data and test data, establishing the basic model, the equipment accounting model, the process condition study and the optimization model by Aspen Plus process simulation software.This study is to calculate of calibration apparatus, material balance, energy balance, chemical equilibrium, pressure balance by based model, to analysis processing capacity of device, calculation of key product loss and the quality of the products, to compute the operating parameters of device such as flooding factor each layer of tray, down-comer velocity, the clear liquid height, the gas-liquid load, to judge the running status and operation flexibility of the rectifying column, to find out the system bottleneck, with equipment accounting model. Study on effects of towers feed position, feed temperature, reflux ratio, amount of product, operating pressure to the quality of the products, the output of products, energy consumption. Under the condition of meet the quality of the products, get a set of optimized operation parameters including larger operation flexibility, higher product yield and lower energy consumption.The calculation process of the Aspen Plus model, accounting model, the working condition of research model and optimization model is convergence, accurate and reliable. The flow error of any system point is rarely more than 5%. The temperature error is rarely more than±2℃. The pressure error is rarely more than±5kPa. The project can reflect the actual running state of current separation system. The calibration of the device accurate, it can be used as an important basis for performance evaluation. Though equipment accounting, determines the system bottleneck is flooding to occur in the deethanizer ET-421 and ethylene tower ET-432. In the range of equipment to withstand ability, using optimization measures that increasing the load of demethanizer condenser and reboiler, can effectively take off the ethylene loss of the top tower to 0.47%. By reducing the recovery position of propylene that the 15 layer, this propylene content of tower kettle can control in 17.7%, produced amount of polypropylene increased to 304kg/h, the load of condenser and reboiler is reduced than 7%.