茂金属聚乙烯气相开车过程动态模拟

Dynamic modeling of the start-up process for metallocene catalyzed gas-phase ethylene polymerization

开车过程作为聚乙烯装置运行的初始环节,对废料量、产品质量等有重要影响,而关于茂金属聚乙烯气相聚合开车过程动态模拟的研究比较少。本文以gPROMS为建模工具建立了气相流化床反应器中乙烯、1-丁烯在茂金属催化剂催化下共聚的动态模型,包括反应动力学、物料衡算、热量衡算等,并利用该模型模拟了乙烯气相聚合开车过程。模拟结果显示,开车过程所用时间、达到稳态后的各项指标与实际装置可以很好地吻合,聚乙烯分子量分布较窄也符合茂金属催化剂单一活性位的特点,表明建立的模型是准确有效的,可用于开展进一步的研究工作。

As the initial part of the process, the start-up procedure has an important effect on the amount of the waste, product quality, and so on. But there is less research on dynamic modeling of the start-up process for metallocene catalyzed gas-phase ethylene polymerization. This paper has developed a dynamic model for the process of ethylene-1-butene copolymerization catalyzed by a metallocene catalyst in a gas phase fluidized bed reactor by means of gPROMS, which includes reaction dynamics, material balance, energy balance, etc. Furthermore, we have made use of this model to simulate the start-up process. The modeling result shows that the model fits well with the actual situation, and the produced polyethylene has a narrow molecular weight distribution which agrees with the metallocene＇s one-site activity characteristic. It also indicates that the model is accurate and efficient, which can be used for further study.