Abstract: The crystallization mechanism of crystallizer, crystal slurry tank and aging kettle and the separation process of centrifuge were studied for the crystallization process in the combined process of crystallization and adsorption separation in PX unit. The calculation model of solid-liquid phase equilibrium for PX crystallization related multicomponent system was selected by PRO Ⅱ simulation software. The simulation modules of crystallizer, crystal slurry tank and aging kettle generated by PX crystal were established. These simulation modules included both solid-liquid phase equilibrium calculation model and crystallization kinetic model. The maximum relative deviations of each component flow predicted by these modules were 0.011%, 0.020% and 0.031% respectively. A complex centrifuge simulation module with filter cake and mother liquor was established. The maximum relative deviation of filter cake and mother liquor flow predicted by the module were 0.010% and 0.009% respectively. A complete simulation software package for crystallization process in PX unit was established, which could be applied in engineering design of PX unit.

Key words: PX unit, crystallization, kinetic model, crystallizer, crystal slurry tank, aging kettle, centrifuge

摘要： 针对对二甲苯(PX)装置结晶与吸附分离组合工艺中的结晶工艺流程,研究了结晶器、结晶晶浆罐和老化釜的结晶机理与离心机的分离过程。利用PRO Ⅱ流程模拟软件选取了PX结晶相关多元体系固液相平衡计算模型。建立了有PX结晶晶体生成的结晶器、结晶晶浆罐和老化釜模拟模块,这些模块含有固液相平衡计算模型及结晶动力学模型。结晶器、结晶晶浆罐和老化釜模拟模块预测各组分流量最大相对偏差分别为0.011%,0.020% 和0.031%。建立了复杂的有滤饼和母液两种产物存在的离心机模拟模块,该模块预测滤饼和母液流量最大相对偏差分别为0.010%和0.009%。建立了完整的PX装置结晶工艺流程模拟软件包,该软件包可用于PX装置的工程设计。

关键词: PX装置, 结晶, 动力学模型, 结晶器, 晶浆罐, 老化釜, 离心机