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<正>在伴有多个反应的分离过程数学模拟中,反应量的存在使模型变量增多,非线性增强.文献[1~3]在普通精馏的基础上,提出了不同的算法来改进收敛性.他们对各种反应类型,均以动力学计算反应量,迭代变量多,算法也较复杂.Doherty针对平衡反应过程,提出了变换组成变量的概念计算反应相平衡.本文引入此概念,并对流率、焓等物理量进行了相应的变换,使变换后的反应精馏过程数学模型在形式上与普通精馏过程的模型完全一致.并以修正的Newton-Raphson法对对二甲苯和邻二甲苯的反应精馏过程进行了计算. 相似文献
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超重力场精馏过程探讨 总被引:1,自引:0,他引:1
在常压、全回流操作条件下,以甲醇-水溶液为物系,研究了超重力场精馏过程中超重力因子、回流量、气相动能因子对超重力精馏装置传质性能和流体力学性能的影响规律;研究了转子结构对超重力精馏装置传质性能的影响.结果表明在超重力场中,精馏过程存在最佳操作条件;转子结构对精馏装置的精馏性能有较大影响.应用最小二乘法建立了超重力装置精馏过程的传质模型与流体力模型. 相似文献
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热集成变压精馏分离水-异丙醇-二异丙胺的工艺模拟 总被引:1,自引:1,他引:0
在分析水-异丙醇-二异丙胺体系共沸特性的基础上,提出了热集成变压精馏工艺. 采用UNIQUAC-RK方程计算气液相平衡数据,并利用实验数据在模拟压力范围内(0.004~1.0 MPa)对UNIQUAC方程中的二元交互作用参数进行修正. 利用ASPEN PLUS过程模拟软件中的RADFRAC严格精馏模型,对提出的热集成变压精馏工艺进行过程模拟与参数优化. 得到了热集成变压精馏分离水-异丙醇-二异丙胺体系的最佳工艺参数、塔内气液浓度分布及精馏塔设备参数等,并通过实验对模拟结果进行验证. 结果表明,热集成变压精馏工艺比常规的变压精馏工艺约节能34.3%. 相似文献
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基于非平衡级和拟均相假设,建立了乳酸提纯反应精馏新工艺实验装置的动态机理模型.通过改进的数值计算方法提高了模型的求解效率,设计并实现了包含物性估算系统的模型仿真平台,以促进新工艺的工业化应用.利用仿真平台对新工艺装置进行了动态特性分析,在此基础上设计了两种单端质量控制方案:直接物料平衡和间接物料平衡方案.在不同类型和幅度的过程扰动下,分析比较了两种控制方案的调节性能.结果表明直接物料平衡方案控制品质优于间接物料平衡方案,可在不同扰动情况下满足过程的产品质量和转化率的联合控制要求.非平衡级动态机理模型能够反映反应精馏过程的动态特性,分析发现反应精馏过程有着独特的过程特性,基于机理模型的仿真平台是分析反应精馏特性的有效工具. 相似文献
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针对氰乙酸甲酯传统的间歇精馏分离过程,提出了连续精馏分离氰乙酸甲酯的三塔、四塔和五塔工艺流程,并对3种分离流程进行工艺分析,确定了连续精馏五塔分离工艺.利用ASPEN PLUS软件中的RADFRAC精馏模型和WILSON方程对五塔精馏分离流程进行优化模拟计算,得到了该流程的最佳工艺操作参数及相关的设备参数.生产数据表明,与目前普遍采用的间歇精馏工艺相比,能耗降低了近30%,产品收率提高了2.4%,为氰乙酸甲酯的连续分离开辟了一条新的工艺技术路线. 相似文献
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反应精馏及其研究进展 总被引:13,自引:0,他引:13
反应精馏是化学反应和精馏分离耦合在一个设备中进行的操作。简述了反应精馏技术,介绍了稳态均相反应精馏过程模拟的平衡级模型、非平衡级模型、非平衡池模型、统计模型、微分模型以及相应的计算方法,并指出了今后的研究方向。 相似文献
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催化蒸馏合成乙二醇乙醚的过程模拟 总被引:17,自引:1,他引:17
修正了非平衡级速率模型,使之能适用于催化蒸馏过程的模拟.此催化蒸馏塔的精馏段和提馏段为一般的填料塔结构,而反应段为CR&L公司提出的特定结构的催化剂填充层.采用专门测定此特殊结构的催化剂填充层的气膜和液膜传质系数关联式来计算反应段中的传质速率,用Onda的关联式计算精馏段和提馏段填充层中的传质速率.结合在NKC-01分子筛催化剂上环氧乙烷与乙醇反应的动力学方程式,采用Newton-Raphson技术完成了催化蒸馏合成乙二醇乙醚过程的模拟,结果是令人满意的. 相似文献
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《Chemical Engineering and Processing: Process Intensification》1988,24(3):133-143
A distillation tower algorithm which accounts for two liquid phases on some trays is presented. The major assumptions being made are constant molal overflow, uniform pressure across the tower, ideality of the vapour phase and 100% tray efficiencies. A simplified inside—-out technique is used to achieve convergence to the steady-state solution. In an inner loop vapour and average liquid compositions are calculated. In the outer loop an efficient phase-splitting algorithm developed by the authors is used where necessary to calculate estimates of the liquid-liquid equilibrium compositions. In this outer loop volatility parameters are also updated.Simulation results for example problem 2 by Block and Hegner compare well with those reported by these authors. 相似文献
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In this paper, we propose a novel algorithm for the rigorous design of distillation columns that integrates a process simulator in a generalized disjunctive programming formulation. The optimal distillation column, or column sequence, is obtained by selecting, for each column section, among a set of column sections with different number of theoretical trays. The selection of thermodynamic models, properties estimation, etc. is all in the simulation environment. All the numerical issues related to the convergence of distillation columns (or column sections) are also maintained in the simulation environment. The model is formulated as a Generalized Disjunctive Programming (GDP) problem and solved using the logic based outer approximation algorithm without MINLP reformulation. Some examples involving from a single column to thermally coupled sequence or extractive distillation shows the performance of the new algorithm. 相似文献
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Young Sei Lee Moon Gab Kim Dong Myeong Ha Akiyoshi Oda Chikara Ito Tsutomu Aragaki Hideki Mori 《Korean Journal of Chemical Engineering》1997,14(5):321-324
Multicomponent packed column distillation is simulated using a rate-based model and the simulation results are compared with
the experimental results obtained from a 0.2 m diameter pilot-scale packed column. The simulation algorithm used is previously
proposed by the authors, which based on an equation-tearing method for (6c+7) equations of one packing segment and the whole
column is solved by an iterative segmentwise calculation with the overall normalized θ method for acceleration. The performance
of two packings is examined by simulating the pilot-scale column experiments using the published correlations for estimating
liquid and vapor phase mass transfer coefficients and an effective interfacial area. 相似文献
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Nonlinear feedback control scheme for reactive distillation column has been proposed. The proposed control scheme is derived
in the framework of Nonlinear Internal Model Control. The product compositions and liquid and vapor flow rates in sections
of the reactive distillation column are estimated from selected tray temperature measurements by an observer. The control
scheme is applied to an example reactive distillation column in which two products are produced in a single column and the
reversible reaction A+B=C+D occurs. The relative volatilities are favorable for reactive distillation so that the reactants
are intermediate boilers between the light product C and the heavy product D. Ideal physical properties, kinetics, and vapor-liquid
equilibrium are also assumed. It is shown that the proposed control scheme keeps tight product composition control. 相似文献
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2-Methylpropylacetate synthesis via catalytic distillation 总被引:1,自引:0,他引:1
The paper deals with a 2-methylpropylacetate synthesis process development. The process is based on esterification of acetic acid with 2-methylpropanol by the reactive distillation method. A column in which separation of the reaction products takes place together with esterification in catalytic active separation packing is utilized in this process. Computer simulation of catalytic distillation has been performed to study the process and to evaluate the pilot plant experimental data. KATAPAK® S structural packing was used in the reaction zone, while stripping and rectifying sections of the column were packed by CY® packing. A good agreement between the simulation results and pilot plant data has been achieved. 相似文献
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In this paper heat exchange coefficient and separation efficiency of an annular structured internal heat-integrated distil ation column (HIDiC) were experimental y measured. About 50%heat of the inner ... 相似文献
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Distillation-pervaporation in a single unit (DPSU) column can perform separations that are not possible in conventional distillation by overcoming distillation boundaries. Unlike conventional hybrid distillation-pervaporation columns, in a DPSU system the pervaporation membrane is located inside the column. The separation by distillation and pervaporation is carried out simultaneously inside the same column section. In a previous work, a simplified model was used to design and analyze distillation-pervaporation in a single unit (DPSU) systems with a hybrid rectifying-pervaporation section, where the membrane constitutes the whole section. In this study, this simplified model is applied to DPSU columns where the membrane partially constitutes the rectifying or the stripping sections, including the model derivation of the stripping section and the operation leaves. The simplified model is applied for the separation of two mixtures with different Serafimov's topology classifications: acetone-isopropanol-water (topology type 1.0-2) and ethyl acetate-ethanol-methanol (topology type 2.0-2b). Thermodynamic limitations are identified for the separation of the ethyl acetate-ethanol-methanol mixture. Multiple operation leaves are produced depending on the liquid composition at the beginning of the membrane section, hindering the conditions that help to overcome the distillation boundary through a DPSU column. For some conditions, a section that is partially constituted by a membrane performs better than if the membrane constitutes the whole section. 相似文献
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Analysis of the environmental impact of butylacetate process through the WAR algorithm 总被引:1,自引:0,他引:1
The WAR algorithm, a methodology for determining the potential environmental impact (PEI) of a chemical process, is applied to the case study of n-butyl acetate production. Two different schemes are considered: the conventional process, in which the reaction and separation are carried out in separated devices, and the reactive distillation process in which the reaction and separation are carried out in a packed column simultaneously. The WAR algorithm allows determining which process is better from the point of view of generation of PEI into the process, based on the output wastes and energetic consumption. 相似文献
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An application of a cascaded Clarke-Gawthrop self tuning regulator (STR) to a Karr liquid-liquid solvent extraction column is presented. The Karr column, a reciprocating plate column, exhibits nonlinear asymmetric responses which are complex functions of the operating conditions and requires adaptive control in order to prevent instability. The outer loop of this cascade scheme controls the extract concentration of the continuous phase while the inner loop controls the hydrodynamic holdup in the column and prevents flooding. The manipulated variable was the frequency of reciprocation. The STR-STR cascade arrangement is compared with a fixed parameter Proportional plus Integral (PI) controller in the outer loop and an STR in the inner loop. 相似文献