气相卧式搅拌釜聚丙烯反应器的模拟及多稳态分析

聚合过程是强放热的非线性过程,这类过程一般存在多稳态现象,且不同的稳态具有不同的局部稳定性.采用气相卧式搅拌釜聚丙烯反应器的Innovene工艺是目前生产聚丙烯最先进的工艺之一.本文开展了该反应器的稳态模拟与多稳态分析研究,对平稳生产、新牌号开发都有着重要的意义.利用Polymer Plus建立了更符合实际且适用于稳定性研究的气相卧式搅拌釜聚丙烯反应器非等温模型,以GPC数据进行聚丙烯反应网络的参数反演.通过灵敏度分析求解系统的多稳态解,通过推理分析的方式判断各个反应区域的稳定性,解决了该问题多稳态研究中的稳定性判断问题,并通过稳定性分析,从本质安全角度出发识别出适于操作的稳态点范围.     

气相丙烯聚合反应器定态模拟

建立了气相丙烯聚合CSBR反应器的定态模型,通过计算,考察了反应器的热稳定性及各工艺参数即催化剂进料量、循环丙烯量、新鲜丙烯进料量和温度对反应器定态行为的影响.研究结果表明:反应器是在假稳态点下操作的,循环丙烯量是影响体系温度的主要因素,反应温度随催化剂进料量和新鲜丙烯进料温度的增加而增大.随循环丙烯馈的增加而降低;体系压强与温度成反向变化关系.     

乙炔加氢反应器二维非均相机理动态建模及分析

乙炔加氢反应器具有非线性、慢时变的特点,当前用于预测控制的模型过于简化,使得对反应器长期运行的控制效果难以达到最佳,因此有必要建立精确的模型作为乙炔加氢反应器的实验室虚拟装置,研究更加有效的控制方法。通过机理分析的方法建立了乙炔加氢反应器严格的二维非均相动态数学模型,并且考虑了催化剂失活的问题。基于动态流程模拟软件gPROMS分析了重要模型参数对反应器稳态模拟的影响,为不同的装置选择参数提供了依据,并且针对本文模拟的实际对象提供了一组数据。模拟分析了催化剂失活对于系统长期运行的影响。对所建立的动态数学模型进行了动态模拟,结果基本反映了实际生产情况。将动态机理模型线性化,得到动态机理模型在不同操作点上的线性状态空间模型特征值,以此进行稳定性分析。动态模拟和稳定性分析的结果表明,在反应温度控制开环的条件下,所研究的反应器在大范围的操作点是稳定的。     

丙烯氯醇化反应过程的模型化

将单塔自然液相循环的丙烯氯醇化反应器视为两个串联的鼓泡塔 ,在两塔分别进行溶氯和氯醇化反应 .在对反应机理和宏观动力学进行探讨的基础上 ,建立了反应器的一维定态模型 .通过流程模拟 ,研究了操作参数对反应结果的影响 .结果表明 ,所建立的一维定态模型能正确描述重要操作参数的影响规律     

平板微反应器中甲烷蒸气重整与甲烷催化燃烧的耦合分析

针对间隔式甲烷蒸气重整与甲烷催化燃烧的平板微反应器,建立了二维稳态多组分传输反应的耦合模型,探讨在甲烷催化燃烧侧进口条件不变的情况下,甲烷蒸气重整侧进口速度以及反应通道长度对反应性能及热量匹配的影响.结果表明,可以通过调整重整侧甲烷进口速度来实现热量的良好匹配;增大反应通道的长度可以提高重整侧的甲烷转化率和降低反应器出口的温度.     

甲苯液相催化氧化过程稳态模拟

通过分析甲苯氧化反应的特点,依据反应动力学模型和物料衡算关系,提出了对甲苯液相催化氧化过程进行稳态模拟的方法,研究了稳态连续操作时反应温度、进料甲苯流量等操作条件对苯甲酸浓度的影响。采用的反应动力学模型考虑了苯甲醛、苯甲醇等组分对反应的影响,并用生产数据对反应动力学参数进行了重新回归。使用回归得到的动力学参数进行稳态模拟,结果显示：苯甲酸质量分数的计算值与测量值的相对误差在5%以内。     

稳态反应模型在气相聚乙烯反应器中的应用

通过对气相流化床聚乙烯工艺稳态反应模型的应用进行分析，讨论了中间控制参数温度、氢气乙烯摩尔比、共聚单体乙烯摩尔比、催化剂产率等输入变量对反应器输出变量树脂性能－熔体流动指数（MI）的影响。选择工业实例，对系统出现波动后人工调控MI与利用稳态反应模型的计算机调控MI的过程分别进行了计算，并对2种调控过程进行了比较，证明了稳态反应模型在工业质量控制中的优越性。     

基于HYSYS的烷烃异构化反应过程的模拟与优化

轻质烷烃异构化技术是满足汽油质量升级要求的重要工艺路线。以某炼厂异构化固定床反应装置为研究对象,将异构化汽油划分为10个集总并建立反应网路,同时以实际生产数据为基础进行了动力学参数计算,并建立了HYSYS平推流速率反应器的稳态模型。利用此模型对异构化装置关键操作参数与产品性质的平衡关系进行灵敏度分析,为异构化反应器操作调整提供科学的理论指导。并制定了装置优化方案,即继续采用一次通过流程,调节反应器运行温度至130.4℃后与重整油按比例调和后去下游装置,或通过稳定分离单元将部分低辛烷值单甲基戊烷循环至反应器,提高后续异构化汽油辛烷值。     

加氢反应器简体热应力有限元分析

通过有限元软件ANSYS,分别计算了加氢反应器筒体在启动和稳态操作情况下的温度及热应力分布.结果表明,加氢反应器堆焊层与基层的交接区产生热应力集中,同时温度的快速上升对筒体热应力也有一定的影响.     

低温精馏过程模拟及其分离特性分析(Ⅱ)带有侧线返回进料的低温精馏塔模拟

应用严格的热力学模型研究了带有侧线返回进料的氢同位素低温精馏塔的分离特性.根据氢同位素低温精馏体系的特点，以平衡级模型为基础建立了氢同位素低温精馏稳态模拟模型，确定了模型方程适宜的求解方法.塔的一股侧线出料流股经过一个平衡反应器完成平衡反应后，作为内部进料流股，与原外部进料混合后重新进入精馏塔内进行分离操作.通过对带有侧线返回进料的塔的计算模拟阐明了这一侧线流股对塔分离特性的影响.在平衡反应器内，HD部分分解为H₂和D₂，塔顶产品中H₂的浓度增加了8.635%，塔底D₂的浓度增加了11.327%.     

REACTOR MODELING OF AN INNOVATIVE LIQUID-SOLID CIRCULATING MOVING BED FOR THE SYNTHESIS OF LINEAR ALKYL BENZENES

The circulating moving bed is an innovative coupled reactor for producing linear alkyl benzenes. It can be used with shorter life span catalysts compared to traditional fixed bed reactors. A model is developed in which the effect of catalyst deactivation on the reaction is simulated using infinitesimal balance equations. The results of step changes between steady states and unsteady states have been calculated with the model.     

REACTOR MODELING OF AN INNOVATIVE LIQUID-SOLID CIRCULATING MOVING BED FOR THE SYNTHESIS OF LINEAR ALKYL BENZENES

The circulating moving bed is an innovative coupled reactor for producing linear alkyl benzenes. It can be used with shorter life span catalysts compared to traditional fixed bed reactors. A model is developed in which the effect of catalyst deactivation on the reaction is simulated using infinitesimal balance equations. The results of step changes between steady states and unsteady states have been calculated with the model.     

液固循环移动床反应-再生系统的颗粒循环量调节和输送

液固循环移动床反应－再生系统由上下两个或两个以上的反应室、再生室、连通管和颗粒提升管组成。颗粒经再生室、反应室向下移动,进入输送管后被向上输送返回至再生室。颗粒循环能力决定了反应室和再生室内的颗粒更新速率。是循环移动床操作的关键之一,对反应器的颗粒循环进行了实验研究,提出了一种射流输送和调节结构并对射流输送行为进行了模拟计算。     

Syngas chemical looping process: Dynamic modeling of a moving‐bed reducer

The syngas chemical looping process coproduces hydrogen and electricity with iron oxide based oxygen carriers in a circulating moving bed system. In this article, a one‐dimensional (1‐D) dynamic model is developed to simulate the countercurrent gas–solid reactive flow in the moving‐bed reducer. This model is validated by TGA and bench‐scale experiments. Both the steady state and dynamic composition profiles are obtained to help understand the reaction and reactor behaviors. Numerical simulation on the effects of reactor length is conducted to optimize the moving‐bed reducer design. It is also found that minor variations in the feed rate ratio near a critical point that is represented by the reaction equilibrium could yield a significant difference in the time required for the reactions to reach a steady‐state operation. Such a difference has an important practical implication in that the moving‐bed reducer should be designed and operated to circumvent the critical point. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3432–3443, 2013     

Sorbent-enhanced/membrane-assisted steam-methane reforming

Thermodynamic equilibrium and kinetic reactor models are used to simulate a fluidized bed membrane reactor with in situ or ex situ hydrogen and/or CO₂ removal for production of pure hydrogen by steam methane reforming. In the equilibrium model, the membranes and CO₂ removal are located in separate vessels downstream of the reformer. As the recycle ratio increases, the overall performance approaches that where membranes are located inside the reactor. Whether located in situ or ex situ, hydrogen removal by membranes and CO₂ capture by sorbents both enhance hydrogen production. In the kinetic reactor model, a circulating fluidized bed membrane reformer is coupled with a catalyst/sorbent regenerator. Sorbent enhancement combined with membranes could provide very high hydrogen yields. In addition, since carbonation is exothermic, with its heat of reaction similar in magnitude to the endothermic heat of reaction of the net reforming reactions, sorbent enhancement can provide much of the heat needed in the reformer. The overall heat needed for the process would then be provided in a separate calciner, acting as a sorbent regenerator. While the technology is promising, several practical issues need to be examined.     

液固循环移动床反应器操作规律和模拟

液固循环移动床反应 -再生系统由上下两个或两个以上的反应室、再生室、连通管和颗粒提升管组成 .颗粒经再生室、反应室向下移动 ,进入输送管后被向上输送返回至再生室 .颗粒循环能力和各流股间的窜液行为是循环移动床连续操作的关键 .通过实验对该液固循环移动床的颗粒循环、斜管窜液和连接段窜液的规律进行了研究 ,同时建立了循环移动床的液固流动模型 ,并进行了模拟计算     

Simulation of activity loss of fixed bed catalytic reactor of MTO conversion using percolation theory

In this investigation, a reactor model for prediction of the deactivation behavior of MTO's porous catalyst in a fixed bed reactor is developed. Effect of coking on molecular transport in the porous structure of SAPO-34 has been simulated using the percolation theory. Thermal effects of the reaction were considered in the model and the temperature profile of the gas stream in the reactor was predicted. The predicted loss in catalyst activity with time-on-stream was in very good agreement with the experimental data. The resulting coke deposition and gas temperature profiles along the length of reactor suggested a reaction front moving toward the outlet of the fixed bed reactor at the operating experimental conditions of 1 h⁻¹ and 723 K for methanol space velocity and inlet temperature, respectively. Effects of space time, coordination of Bethe network, and effective diffusivity of component in reaction mixture on the reactor performance are presented.     

Study on the stress distribution and modeling of the stand pipe in a circulating moving bed

The liquid-solid circulating moving bed reactor is a novel one, which consists of two reaction chambers and a particle transport system. Particles move down to the lower reaction chamber from the upper reaction chamber through a coupling standpipe and to the particle transport system through a bottom standpipe, and are then conveyed into the upper reaction chamber through a riser. A stress distribution model based on the equations of continuity and momentum balance in the reactor is established and used for simulations which shows that the stress concentration regions are at the coupling standpipe and the bottom of the regeneration chamber. To reduce the largest stress in the stress concentration regions and to minimize catalyst consumption, the regeneration chamber should be designed to give a low ratio of height to diameter. Zoning diagrams of the flow patterns in the bottom standpipe are proposed and the flow patterns can be readily deduced from the pressure gradient.     

甲醇制烯烃反应动力学及反应器模型研究进展

甲醇制烯烃（MTO）工艺是现代煤化工领域的研究热点,MTO反应动力学及其反应器模型研究是高效反应器开发和工业装置操作优化的基础。本文综述了甲醇制烯烃反应动力学研究进展,详细论述了机理型动力学模型、八集总动力学模型、五集总动力学模型,指出集总动力学模型适用于描述MTO反应过程,如何考虑水、积炭等因素的影响是MTO动力学研究的难点和关键。结合现有动力学模型,评述了MTO反应过程在工业规模的固定床反应器、提升管反应器、循环流化床反应器、湍动流化床反应器中产物分布和转化率模拟情况,结果表明：循环流化床反应器和湍动流化床反应器适合MTO工业过程。最后指出,甲醇制烯烃反应动力学下一步研究方应集中于工业规模流化床反应器气固两相流动模拟,以及与动力学模型结合获得准确预测工业反应结果的MTO反应器模型。     

移动床甲醇制丙烯技术的工艺与工程

提出了一种新型的移动床甲醇制丙烯工艺（MMTP）并进行工程化分析。首先,根据反应器必须与催化剂的反应失活速率相匹配的原则,认为移动床是与失活速率处于中等水平的ZSM-5催化剂相匹配的最佳反应器。因此,MMTP工艺在充分发挥ZSM-5催化剂多产丙烯优势的基础上,结合移动床的中等循环速率进行反应-再生,从而实现催化剂高产丙烯的连续化与稳定化;其次,针对MTP反应的强放热特点,对比了流化床工艺的一步法操作与固定床工艺的两步法操作,发现MMTP工艺采用两步法操作既能合理地分配反应热,又能灵活地调控产品分布;最后,通过换热网络的优化设计与醇油共炼的工艺集成,使得MMTP工艺在节水节能的同时仍具有高丙烯收率。目前,在现有的MMTP工艺技术基础上,已经完成1万吨丙烯/年的工艺包设计,技术和经济的竞争优势十分明显,市场推广应用前景广阔。