基于相对分子质量分布指标的HDPE生产过程模拟

提出一种以相对分子质量分布为指标,关联熔体流动速率(MFR)的高密度聚乙烯(HDPE)工业生产过程流程模拟方法。基于Innovene S HDPE装置工业生产中的聚合过程,采用流程模拟软件Aspen Plus Polymers建立基于严格过程机理的HDPE过程框架模型,结合工业操作参数及实验数据,计算聚合物相对分子质量、相对分子质量分布指数,并关联MFR,利用TableCurve软件拟合得到HDPE的MFR模型。通过相对分子质量和MFR随氢气用量变化的灵敏度分析,在乙烯用量一定的条件下,氢气流量为0.20~0.45 kg/h,生产的相对分子质量分布呈双峰的管材专用HDPE PN049-030-122为优等品。     

基于联立法的乙烯淤浆聚合牌号切换过程动态模拟

以乙烯淤浆聚合流程为研究对象,建立了包含动力学和热力学的动态机理模型,采用有限元正交配置法对控制变量和状态变量同步离散化,实现了全联立动态模拟。热力学物性计算采用Kriging函数估计,可适用于多个工况,最大误差不超过2%。利用Aspen Plus 5个牌号工况的数据,进行了模型稳态验证,并实现了牌号切换动态模拟,计算了平均分子量等质量指标,与Aspen Dynamic曲线吻合较好,为牌号切换的优化奠定了基础。     

Aspen Plus模拟在氟化工中的应用研究

Aspen Plus是生产装置设计、稳态模拟和优化的大型通用流程模拟系统。全球各大化工、石化、炼油等过程工业制造企业及著名的工程公司都是Aspen Plus的用户。举例介绍了Aspen Plus模拟在氟化工中的应用,分析可能存在的困难,并展望Aspen Plus模拟在氟化工中的应用前景。     

基于COM技术的MATLAB与AsPen Plus接口及高级应用

基于COM技术研制开发了MATLAB和Aspen Plus的接口工具箱MAP,实现了在MATLAB环境下对Aspen Plus中数据进行读写操作,并控制模拟的运行.MAP接口将MATLAB计算能力和Aspen Plus的模拟能力结合在一起,扩展了Aspen Plus的高级应用.通过精馏塔进料软测量的示例,阐述了如何通过MAP接口来调用自主开发的禁忌搜索优化算法,解决由于Aspen Plus中的优化算法的局限性所无法实现的模拟与优化问题.     

基于Aspen Plus的动力学子程序开发及固定床反应器模拟

介绍了Aspen Plus用户子程序的开发过程。采用Aspen Plus的Rplug模块,结合Fortran动力学子程序,对固定床反应器进行了模拟,并与考虑了径向温度、浓度分布的二维模拟结果进行了比较。通过对比表明AspenPlus与动力学子程序相结合的方法模拟固定床反应器结果可靠。     

规模化聚酯装置酯化过程的机理模型化

聚对苯二甲酸乙二醇酯(PET)酯化反应体系的热力学物性计算、动力学常数的整定是实现聚酯工业生产装置模型化的2个重要部分。对聚酯酯化过程的各主副反应——酯化反应、缩聚反应、水解反应、醇解反应、二甘醇生成反应进行机理分析和参数比较,确定了聚酯生产全流程模拟的动力学常数的合理范围。通过动力学参数对目标产物对苯二甲酸、二甘醇、乙二醇、PET质量流量影响的灵敏度分析,修正了反应动力学常数使之适应特定的工业装置,结合物性计算方程建立了规模化聚酯装置酯化工段的机理型数学模型。利用不同生产负荷的工业数据对模型进行了验证,其误差在3%以内。     

氯乙烯精馏过程的模拟与分析

采用Aspen Plus通用模拟软件模拟计算了氯乙烯双塔精馏过程,得到了适宜的操作参数,对氯乙烯的工业生产具有一定的指导意义。     

二氟一氯乙烷的精馏过程模拟与分析

本文利用Aspen Plus流程模拟软件对HCFC-142b精馏过程进行了模拟和计算,分别考察了进料板位置、操作回流比和馏出物/进料比等参数对精馏过程的影响,得到了适宜的操作条件.     

利用Aspen Plus模拟工业MTBE装置

MTBE(甲基叔丁基醚)是一种提高汽油辛烷值的添加剂和化工原料。工业上要提高MTBE产量、减少装置能耗,就需要探索最优的操作条件。文中运用Fortran语言编写反应动力学程序,并嵌入Aspen Plus中来模拟复杂的工业MTBE装置,模拟结果与工业装置较好吻合。通过模拟结果分析了反应精馏塔的温度、组成分布和MTBE生成速率,同时考察改变工艺参数对产品MTBE纯度和异丁烯转化率的影响。优化后MTBE产品质量分数高达98.5%,异丁烯转化率为99.7%。     

裂解C_9馏分中分离石油树脂原料工艺流程模拟

研究了从裂解C_9馏分中分离石油树脂原料的工艺流程。使用Aspen Plus过程模拟软件对整个分离流程进行模拟计算,选择了合适的压力,优化了理论板数、回流比和进料位置,获得较佳的工艺参数,从而为设备的设计计算和工业应用提供理论与实践基础。     

苯乙烯连续搅拌釜式本体聚合工业过程模拟

采用了机理分析建模法对苯乙烯工业本体预聚过程进行了模型化研究，并通过对流体在反应器中混合模式的分析，表明预聚釜可视作全混流（CSRT）反应器模型，此外对热聚合机理中的引发级数和终止反应进行了考察，利用预聚釜的工业数据确立了三分子引发，同时考虑偶合和歧化终止以及向溶剂链转移的反应机理模型，并选取了合适的动力学参数，然后利用工业装置采集的数据进行了模拟，从宏观转化率，平均分子量和微观分子量分布两个方面对模型进行了验证，模拟结果和工业数据符合得较好，该模型方程不仅能模拟稳态，非稳态预聚过程，同时也为装置开发新产品，改造扩建，优化操作方案等提供了理论基础。     

Multiobjective dynamic optimization of a semi-batch epoxy polymerization process

Multiobjective Pareto optimal solutions for epoxy semi-batch polymerization process are obtained by adapting nondominated sorting genetic algorithm II (NSGA II). The objective is to produce polymer of maximum possible number average molecular weight (M_n) with a specified value of polydispersity index (PDI) and number average molecular weight in minimum possible time. The M_n and reaction time are, therefore, taken as two objectives where the first one is maximized and the second one is minimized. The decision variables are addition profiles of various reactants and the reaction time itself and PDI is treated as a constraint. In another optimization study, the time intervals are also been changed from hourly addition assumptions to equal interval additions for an optimized time frame. Additionally, similar analysis has been performed with a new addition strategy with total additions of reactants very close to available experimental conditions. Sensitivity analysis for estimated kinetic parameters and analysis for stabilization of products are also studied. A validated model, taking care of required physico-chemical aspects of the proposed reaction mechanism, is a prerequisite for this kind of study.     

Simulation and optimization of the continuous tower process for styrene polymerization

The continuous tower process, a popular industrial process for the manufacture of polystyrene, was simulated and optimized. A kinetic model for the thermal polymerization of styrene, which takes into account the Trommsdorff effect and the volume change accompanying the reaction, was developed. This was used to formulate model equations for the continuous flow stirred tank reactor (CSTR) and plug flow reactor (several sections) in the tower process. The model can predict monomer conversion, number‐ and weight‐average molecular weights, polydispersity index (PDI), and temperature at various locations in the unit, under specified operating conditions. Multiobjective optimization of this process was also carried out, for which an adaptation of a genetic algorithm (GA) was used. The two objectives were maximization of the final monomer conversion and minimization of the PDI of the product. The conversion in the CSTR was constrained to lie within a desired range, and polymer having a specified value of the number‐average molecular weight was to be produced. The optimal solution was a unique point (no Pareto sets were obtained). The optimal solutions indicated that the tower process is operated under near‐optimal conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 775–788, 2004     

乳液聚合丁腈橡胶聚合过程的稳态模拟

运用美国Aspen Tech公司研发的Polymer Plus软件模拟乳液聚合丁腈橡胶生产中聚合部分的流程,通过对热力学参数的拟合和反应动力学参数的调整,建立了牌号为N41的丁腈橡胶聚合部分的模型。8个反应釜的模拟结果表明转化率、丙烯腈结合率和数均相对分子质量均符合乳液聚合机理的特性,与生产现场实验室分析结果能较好地吻合,相对误差在4%以内。将此热力学和动力学参数系统应用于牌号为N32的丁腈橡胶的模拟过程中,对参数的准确性进行考察,结果表明反应模型具有较好的适应性,模拟结果与实验室分析结果的相对误差在5%以内。     

基于Monte Carlo方法的聚苯硫醚聚合反应动力学建模

根据聚苯硫醚（PPS）聚合机理及过程分析并通过合理假设,提出了基于Monte Carlo方法的PPS聚合反应动力学模型。利用文献数据对模型参数进行了拟合回归,结果表明动力学模型计算值与相应的实验数据符合良好,并且模型外推预测与相同条件的实验接近,两者偏差小于2%;通过模型对反应物配比的影响进行模拟计算,结果与文献值相符合。最后,通过建立工业PPS聚合反应器模型对工业生产过程进行了模拟计算,结果表明PPS生产过程宜采用多釜串联的方式。相关研究结果可对PPS聚合反应动力学建模和工业过程的设计和优化提供理论依据。     

Systematics and modelling representations of LPG thermal cracking for olefin production

Pyrolysis of hydrocarbons is an important commercial process for the production of ethylene, propylene and 1,3 butadiene. These low molecular weight olefins are among the most important base chemicals for the petrochemical industries for polymer production. A simulation program of the reaction kinetics and coke formation inside the coils of a thermal cracking unit can provide information on the effects of operating conditions on the product distribution. The aim of this study was to develop a mechanistic reaction model for the pyrolysis of LPG that can be used to predict the yields of the major products from a given LPG sample with commercial indices. A complete reaction network, using a rigorous kinetic model, for the decomposition of the LPG feed has been developed, which is used for the simulation of industrial LPG crackers. This model has been adapted using industrial data for the pyrolysis yields of LPG. The present paper attends on the asymptotic coking mechanism and describes the development of a kinetic coking model in the pyrolysis of LPG. Detailed and accurate information about the product distribution, growth of coke layer, the evolution of the tube skin temperatures can be obtained from this simulation. Simulations of this kind can be used to optimize the furnace operation. They can be used as a guide for the adaptation of the operating variables aiming at prolonging the run length of the furnace. The reactor model, as well as kinetic scheme, is tested in an industrial cracking furnace.     

序列分布导向的CGC催化乙烯与1-辛烯共聚过程建模

限制几何构型催化剂(constrained geometry catalyst,CGC)特别适用于乙烯与α-烯烃溶液聚合法制备高性能聚烯烃弹性体POE(polyolefin elastomer)。基于CGC催化乙烯与1-辛烯共聚反应机理,建立了乙烯与1-辛烯共聚反应动力学模型并确定了动力学参数。采用前期实验获得的乙烯消耗速率曲线与催化剂平均活性验证了动力学模型的准确性。基于动力学模型和面向序列结构的共聚机理,建立了乙烯与1-辛烯共聚过程序列分布模型。模型可准确预测序列分布与短支链含量及其随反应条件的变化趋势。结果表明,随着1-辛烯浓度的增加,乙烯序列长度逐渐减小,其平均序列长度线性降低,而1-辛烯平均序列平均长度呈线性增加的趋势。所建模型可为从聚合过程角度调控POE链结构提供理论参考。     

Modeling and control of continuous stirred tank reactor for thermal copolymerization

A mathematical model is developed for solution copolymerization in a continuous stirred tank reactor. For the thermal copolymerization of styrene and acrylonitrile (SAN), the kinetic rate expression for thermal initiation is derived by applying the pseudo-steady-state hypothesis to the intermediates, and the kinetic parameters are estimated by experimental investigation. The moment equations of living and dead polymer concentrations are derived by applying the pseudokinetic rate constantmethod. The model is used to calculate the conversion, the copolymer composition, the weight-average molecular weight, and the polydispersity. It is demonstrated that this model can predict the industrial data very well under various operating conditions. The dynamic analysis of the reaction system enables us to determine the polymer properties against the changes in the operation parameters. It is noticed that the monomer conversion is controlled to some extent by the reaction temperature and the feed monomer fraction. The monomer conversion control of a solution copolymerization reactor is treated with different control algorithms. The fuzzy/proportional–integral–derivative controller shows satisfactory performances for both setpoint tracking and disturbance rejection and can be easily applied to continuous polymerization processes. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:921–931, 1998