气相流化床聚乙烯颗粒粒径分布的定制

基于气相法聚乙烯流化床反应器颗粒粒径分布的预测1],提出了颗粒粒径分布定制模型.通过模型的优化计算,可得到催化剂粒径及其分布、操作气速、反应温度、乙烯浓度和丁烯浓度等生产操作参数,由此进行生产可获得具有良好流态化特性的聚乙烯颗粒粒径分布,能为生产具有特定粒径分布的聚乙烯颗粒提供理论指导.模型由工业装置的生产数据分析了计算结果的合理性.最后,以三种粒径分布的聚乙烯颗粒为例讨论了模型的可行性.同时,运用粒子群优化算法求解模型的非线性规划问题,算法具有调整参数少、收敛速度快和全局优化等优点.

Customization of Particle Size Distribution in Continuous Polymerization Process

Based on the steady-state particle size distribution model proposed in the previous paper published by authors for the industrial fluidized bed gas-phase polyethylene production process, a particle size distribution tailored model (PSD-tailored model) was presented. After considering the restriction of technology, such as operation parameter ranges, the novel PSD-tailored model was solved by using an algorithm named as Particle Swarm Optimization (PSO), and the polyethylene PSD of an assigned objective value could be attained by optimization of the manipulated variable values, such as PSD of catalyst particles, superficial gas velocity, polymerization temperature, the concentration of ethylene and butylenes. Using the above obtained optimized operation parameters, the optimal fluidization quality could be attained and the stability of the production could be improved greatly. Meanwhile, using the PSO method could reduce the parameters needed to be optimized, save the calculation time and attain the global optimization during the calculation. The examples of using the PSD tailored operation strategy for three types polyethylene PSD were illustrated separately, which clarify the optimal strategy of polyethylene PSD tailored production in detail. It is shown that the commercial process could be enormously benefited by the optimal strategy proposed.