固定床F-T合成反应器的稳态和动态行为特性 I.数学模型及其数值计算方法(英文)

讨论了固定床反应器模型的建立过程和工作步骤,确定固定床Ｆ－Ｔ合成反应器用非均相二维模型来描述。总结评价了固定床反应器模型方程的数值计算方法,确定了固定床Ｆ－Ｔ合成反应器模型方程的数值计算方法。     

固定床反应器参数灵敏性与失控分析

本文采用邻二甲苯氧化的复合反应动力学模型分析了固定床反应器的参数灵敏性和失控行为,并与该反应的简单反应动力学模型的研究结果作了比较,发现二者间有显著的差别。本文还考察了固定床反应器对冷却介质流量和进口温度的灵敏性,发现反应器对冷却介质流量和进口温度的发迹极其敏感。因此对于强放热反应过程,考虑反应器对冷却介质的流量和进口温度的参数灵敏性对反应器的设计和控制是必要的。     

生物乙醇重整制氢反应器

生物乙醇重整制氢是一种具有良好应用前景的制氢技术,是当前低碳能源领域的研究热点.发展生物乙醇重整制氢技术的关键是研发在低温下具有高活性和高选择性的新型重整催化剂,以及开发新式高效的催化反应器.本文着眼于反应器对生物乙醇重整制氢过程的影响,综述了国内外固定床反应器、微通道反应器和膜反应器等生物乙醇重整制氢反应器的研究现状...     

微反应器和微聚合反应器

微反应器是指容量仅为零点几μm^3或宽度为1μm左右的反应“容器”，反应在这个微小区域内有控地进行。以表面科学与微制造技术为核心，新型微反应器近年来发展很快。本文介绍五种微反应器，即反相胶束微反应器，聚合物微反应器，固体模板微反应器，微条纹反应器和微聚合反应器，以及它们在各高科技领域中的可能应用。     

均四甲苯氧化制二酐宏观动力学分析

为了提高均四甲苯氧化制均苯四甲酸二酐的收率,以某二酐生产企业生产的高效钒钛催化剂,在固定床反应器中对均四甲苯气相氧化制均苯四甲酸二酐反应体系的动力学进行了研究。首先提出了可能的反应网络,然后设计相关动力学测试实验,建立均四甲苯氧化反应的幂函数宏观动力学模型。进一步的实验和统计分析表明,模型计算值与实验值吻合较好。宏观动力学方程的建立为后续将其用于相应的固定床反应器模拟提供了基础保证。     

阴极冷却固定床电合成乙醛酸的连续过程模拟

联用反应动力学、电荷衡算和物料衡算建立阴极冷却固定床草酸电合成乙醛酸反应器模型方程.针对反应器连续化操作过程,用正交配置法数值求解该模型方程.结果表明,在连续化操作的反应初期,反应液中的乙醛酸能够较快地达到预定浓度,但继续增加反应器的长度,反应的效果不明显.该模型还模拟了分段温控和部分回流对反应的影响.结果表明,分段温控和部分回流均可较好地提高乙醛酸在阴极液中的浓度.计算结果与试验操作基本相符.该结果对阴极冷却固定床草酸电合成乙醛酸的连续化操作工艺和反应器的优化具有重要的参考意义.     

煤在固定床反应器中加压热解成气过程

煤的加压热解是煤炭加压气化中的一个重要阶段,也可单独作为煤转化的一种技术,已经引起了人们越来越多的重视。但目前对于这一过程的了解和掌握还很不够,还需要作大量的深入研究。目前,我国大多数煤气化都采用固定床气化工艺。故本文在小型固定床反应器中,     

多孔Pd/α-Al2O3 活性膜上 1,5-环辛二烯选择加氢

利用微乳液及浸渍技术制备了多孔Pd/α-Al2O3催化活性膜.利用透射电镜、扫描电镜和X射线衍射对微乳液中及α-Al2O3陶瓷膜孔结构中纳米Pd颗粒的形貌和分布进行了表征.分析结果表明,通过浸渍技术,微乳液中的纳米Pd颗粒以几百纳米大小的晶体形态均匀负载于陶瓷膜孔中.在"催化接触器"型膜反应器中,以1,5-环辛二烯催化加氢为模型反应,考察了多孔Pd/α-Al2O3膜的活性与选择性,并与Pd-聚丙烯酸(PAA)有机催化膜反应器、悬浮床反应器和固定床反应器中的催化性能进行了比较.结果表明,Pd/α-Al2O3膜反应器的催化活性与目的产物1-环辛烯的选择性远高于Pd-PAA有机膜反应器和固定床反应器.Pd/α-Al2O3膜反应器在强化传质和消除孔内扩散方面效果显著,这与Pd在陶瓷膜孔中的分布及反应物在膜反应器中的高速流动有关.     

固定床反应器中丙酮酸乙酯在Pt/γ-Al2O3催化剂上的不对称加氢反应

采用固定床反应器对辛可尼定修饰的Ｐｔ／γ－Ａｌ２ｏ３催化剂上丙酮酸乙酯的多相不对称加氢体系进行了研究,同时用高压釜反应器进行了对比,分别取得６０％和９０％的ｅ．ｅ．值。在两种不同的反应器中,溶剂对反应结果的影响不同,在高压釜反应器中乙酸的效果好于乙醇,而在固定反应器中则相反,推测在固定床反应器中催化表面反应机理与所用溶剂的介电常数或其极性有关,以ＣＯ探针分子对辛可尼定在催化剂表面的吸附行为进行了红外光谱研究,表明辛可尼定和金属铂主要通过大π键相互作用。     

甲醇水蒸气重整制氢独立反应探讨

分析了甲醇重整氢反应可能的反应途径，分析结果表明体系中有2个独立反应，则至少应有2个动力学方程才能描述，利用平衡温距的概念，分析了WGS反应在甲醇水重整反应体系中的作用，根据在固定床反应器上的实验结果，证明变换反应不宜出现在动力学模型中，合理的动力学模型认为水蒸气重整反应和甲醇分解反应平行进行，CO和CO2同时生成。     

Dynamic modeling of a H2O-permselective membrane reactor to enhance methanol synthesis from syngas considering catalyst deactivation

In this paper,the effect of water vapor removal on methanol synthesis capacity from syngas in a fixed-bed membrane reactor is studied considering long-term catalyst deactivation.A dynamic heterogeneous one-dimensional mathematical model that is composed of two sides is developed to predict the performance of this configuration.In this configuration,conventional methanol reactor is supported by an aluminasilica composite membrane layer for water vapor removal from reaction zone.To verify the accuracy of the considered model and assumptions,simulation results of the conventional methanol reactor is compared with the industrial plant data under the same process condition.The membrane reactor improves catalyst life time and enhances CO2 conversion to methanol by overcoming the limitation imposed by thermodynamic equilibrium.This configuration has enhanced the methanol production capacity about 4.06% compared with the industrial methanol reactor during the production time.     

Efficient continuous kinetic resolution of racemic 2-aminobutanol over immobilized penicillin G acylase

In this paper, an efficient method was established for continuous kinetic resolution of racemic 2-aminobutanol by selective hydrolysis of N-phenylacetyl (±)-2-aminobutanol over immobilized penicillin G acylase (PGA) in a fixed-bed reactor. Several N-acylated derivatives of 2-aminobutanol were screened in batch experiments, and it was found that the hydrolysis of N-phenylacetyl (±)-2-aminobutanol proceeded smoothly in the presence of immobilized penicillin G acylase with satisfied enantioselectivity. Thus, the reaction parameters were optimized in a fixed-bed reactor. Under the optimized conditions, 39.3% conversion of N-phenylacetyl (±)-2-aminobutanol and 98.2% ee value of S-2-aminobutanol were obtained. This fixed-bed system was operated continuously for 40 h without significant decrease of enzyme activity. It has been demonstrated to be more efficient compared to the batch experiments.     

STEADY-STATE AND DYNAMIC BEHAVIOR OF FIXED-BED CATALYTIC REACTOR FOR FISCHER-TROPSCH SYNTHESIS II.STEADY-STATE AND DYNAMIC SIMULATION RESULTS

In this paper, the steady state and dynamic behavior of the F-T fixed-bed catalytic reactor were discussed. An investigation has been made on the impact of the operation conditions on the steady state behavior of the reactor. A study was made on the reactor dynamic behavior for step changes in the feed temperature, fluid rate and the wall temperature.     

固定床F-T合成反应器的稳态和动态行为特性 Ⅱ.稳态和动态模拟计算结果(英文)

讨论了固定床F－T合成反应器的稳态和动态行为。首先研究了操作条件对固定床F－T合成反应器稳态行为的影响,然后探讨了当反应器进口原料温度、原料流速和冷却介质温度突变后床层的动态响应行为。     

Study on methane fermentation and production of vitamin B12 from alcohol waste slurry

We studied biogas fermentation from alcohol waste fluid to evaluate the anaerobic digestion process and the production of vitamin B₁₂ as a byproduct. Anaerobic digestion using acclimated methanogens was performed using the continuously stirred tank reactor (CSTR) and fixed-bed reactor packed with rock wool as carrier material at 55°C. We also studied the effects of metal ions added to the culture broth on methane and vitamin B₁₂ formation. Vitamin B₁₂ production was 2.92 mg/L in the broth of the fixed-bed reactor, twice that of the CSTR. The optimum concentrations of trace metal ions added to the culture liquid for methane and vitamin B₁₂ production were 1.0 and 8 mL/L for the CSTR and fixed-bed reactor, respectively. Furthermore, an effective method for extracting and purifying vitamin B₁₂ from digested fluid was developed.     

绝热固定床反应器的参数灵敏性

分析了绝热固定床反应器的参数灵敏性,建立了参数灵敏度的微分方程,提出了求解参数灵敏度方程的简便方法,并对固定床反应器中进行的工业反应实例进行了模拟计算和分析。     

Computational fluid dynamics study of the dry reforming of methane over Ni/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst in a membrane reactor. Coke deposition

This work investigates the dry reforming of CH₄ as an important process for the conversion of greenhouse gases to synthesis gas. The mixture of methane and CO₂ is readily available in the greenhouse gas which makes realization of dry reforming of methane process more convenient. The paper is an attempt to numerically analyse by computational fluid dynamics (CFD) the coking and gasification mechanisms in the lab-scale membrane module with a fixed-bed supported nickel catalyst (Ni/Al₂O₃). The concentrations and molar fluxes obtained by the simulation are compared with the experimental profiles to validate the CFD model. It was found that working in a catalytic fixed-bed membrane reactor, in the case of the dry reforming of methane and under specific conditions, was not critical, from the point of view of catalyst deactivation.     

Simulation of nonisothermal reactive liquid chromatography using two-dimensional lumped kinetic model

A nonisothermal two-dimensional lumped kinetic model of reactive liquid chromatography is formulated and applied to simulate the separation of multicomponent mixtures in a fixed-bed cylindrical column operating under nonisothermal condition. The axial and radial variations of concentration and temperature as well as reversibility of the chemical reactions are incorporated in the model equations. The model comprises a system of convection-diffusion-reaction partial differential equations coupled with algebraic and differential equations. Due to the nonlinearity of adsorption and reaction kinetics, it is required to apply an accurate numerical scheme for solving the model equations. In this study, an efficient and accurate high-resolution flux-limiting finite-volume scheme is proposed to solve the model equations. A number of stoichiometrical reactions are numerically simulated to determine the level of coupling between the temperature and concentration profiles. Moreover, the effects of various critical parameters on the process performance are examined. The results obtained are beneficial for understanding reaction and separation processes inside a liquid chromatographic reactor and to improve its performance.     

Nonideal flow in tubular reactors

A compact and flexible method for modeling nonideal flow in tubular reactors is presented. The procedure involves dividing the reactor into discrete elements, each being an ideal reactor, but with characteristics of each assigned stochastically. Flow between cells is also shown as a stochastic behavior. The calculation steps are given in case of a fixed-bed reactor with unidirectional flow.