纳滤膜传质过程的研究

作为一种新型膜分离技术,描述纳滤膜传质过程的数学模型有:不可逆热力学模型、电荷模型、细孔模型以及道南-立体细孔模型和静电位阻模型等.针对这些典型数学模型的建立和应用发展情况进行了重点介绍.并在此基础上,讨论了各种溶质对纳滤膜传质过程的影响.     

投资项目经济可行性综合评价数学模型及应用

根据专家打分的机制提出了一种适用于投资项目经济可行性综合评价的数学模型,同时也提了MSE准则.在此准则下可以创建一个非线性规划的NLP模型.这种数学模型具有简便性、客观性等诸多优点.还提出了投资项目综合评价的分批模型.     

用于浆态床费托合成的错流过滤数学模型的研究进展

分析了浆态床费托合成错流过滤过程中滤膜污染的机理,并分别综述了三相过滤和两相过滤过程中数学模型的研究进展根据阻力不同,将模型分为堵塞阻力模型、滤饼层阻力模型和组合阻力模型.在对现有模型研究总结的基础上,通过对比和分析指出了组合阻力模型是浆态床费托合成错流过滤数学模型研究的方向.     

连续式双膜分离塔研究

本文对由毛细管硅橡胶膜和中空醋酸纤维膜构成的连续式双膜分离塔作了研究.探讨了在不同条件下采用该塔分离双组分混合气体(He-CH_4)的分离性能.建立了连续式双膜分离塔的数学模型.将本模型与已发表的数学模型作了比较,并用实验数据验证了所建立的数学模型.     

反渗透膜元件及膜系统的数学模型

介绍了反渗透膜元件性能指标的差异,讨论了建立性能各异膜元件系统运行模型的必要性,给出了单支反渗透膜元件的运行数学模型,分析了并联及串联膜元件的运行数学模型,从而建立了各类膜系统结构的通用数学模型.     

单元玻璃窑炉富氧燃烧空间的数值模拟研究

本文建立了单元玻璃窑炉富氧燃烧空间三维数学模型,其中气相流动模型由质量守恒定律、动量守恒定律、能量守恒定律和标准k-ε湍流模型组成,化学反应模型使用有限速率/涡耗散模型,辐射传热模型使用离散坐标模型.以年产2万吨玻璃纤维的熔窑为对象,利用Fluent软件对富氧燃烧空间内气体的流动状况和温度分布进行数值模拟.通过模拟结果与现场实测数据进行比较可以看出,该数学模型能够比较客观地反映单元玻璃窑炉富氧燃烧空间的温度场和速度场的分布规律.在此基础上,对喷枪的布置加以调整和改进后得到了更佳的模拟效果,还说明该数学模型对窑炉富氧燃烧在生产过程的研究和应用也有一定的指导作用.     

钴膦催化剂丙烯低压醛化制丁醇数学模型的研究

本文报导丙烯低压醛化制丁醇气液并流填料鼓泡反应器的数学模型的研究.在实验室模型级装置上验证了该数学模型的结果,表明带有接触效率系数的本征动力学方程式可以作为丙烯低压醛化制丁醇的反应器数学模型,为放大设计提供参考.     

模拟流态化床煤燃烧的数学模型

前言有关流态化床煤燃烧器的数学模型已经提出了不少。J.Olofsson(1980)和D.Park 等(1981)曾分别对这些模型在其文章中进行了评论和比较。根据他们的报告和论文,提出的模型都有它们各自的优点和缺点。因此,流态化床燃烧器的数学模型化似乎尚处于发展阶段。     

循环流化床燃烧及气化反应数学模型的概述

本文简要介绍了有关文献中循环流化术煤炭燃烧、气化及生物质气化的数学模型。根据中数学有所使用流体动力学模型的差异，将其分为鼓泡流化床数学模型，拟流体数学模型，区段数学模型，颗粒轨道数学模型及多维数学模型，并着重叙述了各模型所用到的流体动力学模型。     

对苯二甲酸加氢精制反应器的数学模拟

分析了对苯二甲酸加氢精制固定床反应器的传质特性,在对反应器进行合理简化后,建立了对苯二甲酸加氢精制反应器的非均相一维平推流数学模型,对有关物性数据和模型参数进行了计算.利用该数学模型对工业装置对苯二甲酸加氢精制反应器进行了模拟计算,计算了各组分沿反应器床层的浓度分布.模拟结果与实验数据相吻合,说明建立的数学模型是可信的.     

Numerical Simulation on Gas-Solid Two-Phase Turbulent Flow in FCC Riser Reactors(Ⅰ) Turbulent Gas-Solid Flow-Reaction Model

Gas-solid two-phase turbulent flows,mass transfer,heat transfer and catalytic cracking reactions areknown to exert interrelated influences in commercial fluid catalytic cracking(FCC)riser reactors.In the presentpaper,a three-dimensional turbulent gas-solid two-phase flow-reaction model for FCC riser reactors was devel-oped.The model took into account the gas-solid two-phase turbulent flows,inter-phase heat transfer,masstransfer,catalytic cracking reactions and their interrelated influence.The k-V-k_P two-phase turbulence modelwas employed and modified for the two-phase turbulent flow patterns with relatively high particle concentration.Boundary conditions for the flow-reaction model were given.Related numerical algorithm was formed and a nu-merical code was drawn up.Numerical modeling for commercial FCC riser reactors could be carried out with thepresented model.     

Numerical Simulation on Gas-Solid Two-Phase Turbulent Flow in FCC Riser Reactors(Ⅱ) Numerical Simulation on the Gas-Solid Two-Phase Turbulent Flow

Numerical simulation on the flow,heat transfer and cracking reactions in commercial fluid catalyticcracking(FCC)riser reactors were carried out employing the developed turbulent gas-solid two-phase flow-reac-tion model for FCC riser reactors given in Part Ⅰ of the present paper.Detailed information about the turbulentflow fields in the riser reactor obtained revealed the basic characteristics of the gas-solid two-phase turbulentflows when heat transfer and catalytic cracking reactions were co-existing in the riser.Results showed that thedistributions of the flow,the turbulence kinetic energy and the catalyst particle concentration are not uniform inthe axial,radial and tangential directions.The most complicated part of the riser reactor is the feed injectingzone.The complicated configuration of the turbulent gas-solid two-phase flows would exert a great influence onthe results of interphase heat transfer and cracking reactions.     

两段提升管催化裂化技术

提出了单提升管催化裂化技术的弊端,介绍了两段提升管催化裂化技术的基本原理,分析了两段提升管催化裂化技术的研究情况,最后,讨论了两段提升管催化裂化技术在国内炼油工业的应用。     

小型提升管反应器流动-反应耦合模拟

在提升管气固两相湍流流动模型和重油反应动力学集总模型的基础上,利用Fluent软件建立了催化裂化提升管反应器气固两相流动与反应耦合模型,对实验室小型提升管反应器进行了数值模拟,考察了气固两相的流动、传热、传质与反应过程。结果表明,提升管反应器内气固两相在轴向和径向的流动、传热与反应的分布不均匀。在入口附近。原料和催化剂温度变化显著,各组分的浓度变化剧烈,在提升管上部,变化平缓。反应器出口各组分质量分数的模拟值和实验值基本吻合。说明该模型对提升管反应器出口参数和反应结果具有较好的预测性。     

Interactions of flow and reaction in fluid catalytic cracking risers

Fluid catalytic cracking (FCC) is the primary conversion process in oil refining. The performance of an FCC riser strongly depends on the interactions between oil/catalyst flow and cracking kinetics, but most FCC riser models do not consider such interactions. Accordingly, this work develops a computationally simple model capturing the dominant features of flow‐reaction coupling in the riser's dense phase and acceleration zones. Specifically, the particle–particle collision force and the particle–fluid interfacial force are considered. With a four‐lump kinetic model, the riser model predicts conversion and selectivity from the axial profile of the catalyst‐to‐oil ratio resulting from particle–fluid interfacial momentum transfer. The cracking intensity in the riser bottom zone is much greater than that calculated from conventional riser models, which neglects oil‐catalyst hydrodynamic coupling and catalyst dilution due to volume expansion. The present model compares well with published data and predicts conversion‐selectivity patterns that are qualitatively different from those obtained from conventional models. © 2011 American Institute of Chemical Engineers AIChE J, 2011     

CFD modeling of gas-solid flow and cracking reaction in two-stage riser FCC reactors

The Eulerian-Eulerian approach was applied to simulate the flow behavior and catalytic cracking reactions in the riser reactors of two-stage riser fluid catalytic cracking (TSRFCC) technology. A k-ε-k_p-ε_p-Θ gas-solid turbulent flow model was used, which took account of the particle turbulence and the interaction of turbulence between gas and particle phases. A 14-lump kinetics model was used for simulating cracking reactions. The approach and model were validated with both experimental results and commercial data. The distributions of particle fraction volume and velocity, as well as product yields in the TSRFCC riser reactors were first analyzed. The simulations were then carried out for optimization studies to understand the influence of the operating conditions on the performance of commercial TSRFCC riser reactors. The model and results presented here are valuable for the design and optimization of TSRFCC technology.     

Kinetic modeling of FCC process

Catalytic cracking of petroleum fractions a process termed as FCC is usually carried out in a reactor block with somewhat complicated hydrodynamic regime. The reactor block is considered as a combination of two different reactors. The riser is a near ideal plug-flow displacement of the catalyst and reaction mixture, while the main reactor vessel (separator) is considered as an ideal mixing CSTR. Temperature gradient along the plug-flow riser can vary on a linear and non-linear dependence. This is reflected by the thermal effect on the cracking products, along the altitude of the riser. Moreover, it can exert a considerable influence on the selectivity of the process in general, as characterized by the diversity of different hydrocarbon groups both in the gaseous and liquid products. The fluid catalytic cracking (FCC) is a process of conversion of a heavy oil fraction into lighter products in a catalytic fluidized reactor. The chemical composition and the structure of the feed are reflected on the catalyst's selectivity and the amount of coke deposited. It is, therefore, necessary to consider the feed type on modeling the process. Cracking reaction in the model was represented as a five-stage process. Reaction rates for the plug-flow riser and the ideal mixing separator are described mathematically in differential and algebraic forms. The model takes into account, exponential dependence of the specific reaction rate on temperature, as well as reflects the influence of the real and bulk catalyst densities, circulation rate, equilibrium and fresh catalyst's activities, reactor pressure, feed rate and unit construction. The model was developed based on a data taken from an industrial FCC unit, that were used to compute the kinetic constants and other parameters. Concrete computed kinetic parameters were compared with corresponding experimental data for adequacy. FCC process is in constant technological development with modernization of especially the riser reactor. Kinetic modeling of the catalytic FCC reactor will give a further understanding of the process and explain the complicated mechanism involved for an efficient and optimal conversion of the feed stock.     

Effect of feed atomization on FCC performance: simulation of entire unit

Entire fluid catalytic cracking (FCC) unit, comprising of a riser and a regenerator, is simulated by integrating FCC riser model presented in our earlier work (Chem. Eng. Sci. 56 (2001) 4489) with an FCC regenerator model. The effect of feed atomization (quantified by average drop size generated by the feed nozzle) on the performance of the unit is evaluated.     

下行式循环流化床用于催化裂化过程的数学模拟

采用十一集总动力学,结合气固流体力学行为和轴、径向扩散行为,建立了适合于提升管及下行式循环流化床催化裂化的数学模型,采用此模型对催化裂化过程计算的结果表明,下行床内目的产品选择性显著高于提升管,但在与工业提升管相同的操作条件下,下行床内原料转化率较低,优势不能发挥。适当增加下行床长度、增大床径、使物料循环反应、增加剂油比、提高反应温度或反应压力等可以改善下行床的反应效果。下行床用于催化裂化过程,与之较匹配的应该是具有更高活性的催化剂,研制新型高活性催化剂也是下行床推向工业的重要措施之一。     

催化裂化提升管反应器模型的建立

工业催化裂化提升管反应器内既存在着气固两相的湍流流动,又存在着传热和裂化反应,而且这些过程是相互影响,高度耦合在一起的。本文全面系统地考虑湍流气因两相流动,传质,传热及反应等复杂因素及其相互影响,建立了催化裂化提升管反应器三维气固两相流动反应模型,形成了相应的数值解法,编制了大型的模拟计算程序。由此可对工业催化裂化提升管反应器内湍流气固两相流动进行系统的数值模拟研究。