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SELECTION OF MULTICOMPONENT BATCH DISTILLATION SEQUENCES 总被引:1,自引:0,他引:1
Omar J. Chiotti Hector E. Salomone Oscar A. Iribarren 《Chemical Engineering Communications》1993,119(1):1-21
As in continuous distillation systems, the design of batch distillation begins with the selection of a sequence of separations. This paper considers the usual case where the column processes multicom-ponent mixtures with the recycle of intermediate cuts. It is proved that this cyclic operation does converge to a “steady state” balance. This permits to model batch distillation with recycle as a function of the steady state variables, i.e. without the need of successive simulations to obtain the steady state. Furthermore, we use simplified analytical models which permit a quick approximation to the optimal design of a given sequence, thus aiding the designer in the screening of alternative separation sequences, to preselect one, or a small set of good sequences. 相似文献
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引 言80年代末 ,余国琮、杨志才等[1] 参照连续精馏开工过程的操作方法提出并实验证明了一种新的间歇精馏操作方法─—塔顶累积全回流间歇精馏(流程见图 1) .对于特定的分离任务 ,采用此操作方法间歇精馏与传统的恒回流比操作方法相比 ,能耗比较低 ,可望在工业生产上获得应用 .本文采用此操作方法推导了在理想操作条件下 ,间歇精馏二元理想混合物所需最小气化总量的计算方法 .Fig.1 Flowsheetofbatchdistillationundertotalrefluxandtopaccumulation1,7—produc… 相似文献
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In distillation column control, secondary measurements such as temperatures and flows are widely used in order to infer product composition. This paper addresses the design of the linear static estimators using the secondary measurements for estimating product compositions of distillation columns. Based on the unified framework for the estimator design, the relationships among various static estimators are discussed in terms of the estimator structure. Il is shown that the projection estimator is equivalent to the regression estimators in the special cases. Since the projection estimator heavily depends on the measured inputs such as reflux flow and heat input to the reboiler due to its structural characteristic, the estimation performance is far more sensitive to measurement noise and nonlinearity of them, compared wiih the regression estimators based on the PCR or PLS method. It is also found that the use of the measured inputs leads to performance deterioration of both the projection and regression estimators because of their nonlinear effects on the product compositions especially in high-purity columns. Design guidelines for the PCR and PLS estimators are presented by analyzing the results of the simulation studies on a high-purity column example. The estimator based on the guidelines is robust to sensor noise and has a good predictive power 相似文献
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夹紧区是精馏塔内出现的浓度几乎不变的区域,对于三元物系来说,根据夹紧区在塔内出现的位置可分为:上、中和下加紧区.在无穷板数和任一瞬时釜浓下选择不同的回流比可使分批精馏处于不同夹紧区下操作.文中讨论了三元恒回流比分批精馏过程中夹紧区的演变,在Rayleigh方程的基础上建立了应用夹紧区原理确定多元恒回流比分批精馏最小回流比的方法.该方法并不要求相对挥发度为常数,并且能准确计算顶浓,克服了通常所采用的Underwood公式法的缺陷,为多元分批精馏的简捷设计奠定了基础. 相似文献
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Eduardo Castellanos-Sahagú n Jesú s Alvarez 《Chemical Engineering Communications》2006,193(2):206-232
The two-point composition control problem of binary distillation columns is addressed. First, the exact model-based inventory control problem is studied, yielding the underlying solvability conditions with physical meaning, the limiting behavior attainable with any controller, and its equivalence with nonlinear geometric and MPC controllers. This control behavior is recovered via a measurement-driven linear controller made of a pair of decoupled PI loops and a static interaction compensator. A closed-loop dynamics study formally shows the recovery feature and provides stability conditions coupled with conventional-like tuning rules. The controller implementation needs only four static parameters that have direct physical meaning and can be estimated from plant data and/or simulation packages. The proposed technique is tested with two representative examples in the presence of actuator errors, measurement delays, and load disturbances, matching or improving the behavior obtained with previous schemes. 相似文献
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Raymond C. Waggoner 《Chemical Engineering Communications》1990,90(1):1-21
An analog of the Rayleigh Equation has been applied for many years to describe batch distillation with rectification for binary mixtures. A solution is obtained by iterative graphical computations followed by numerical integration. When the batch distillation algorithm is stated in terms of distillate composition a computational non-iterative soluton may be obtained. For a binary separation this expression may be solved on a programmable calculator and the integral may be obtained in segments to describe the progress of the operation expressed in terms of the quantity remaining in the still-pot. This variable is not a linear function of time since even at constant reboiler duty the boil-up rate varies as the still-pot composition changes. If the time rate of the operation is to be determined, this effect must be considered. Procedures have been developed to describe the time-responses of the plate compositions and temperatures, the boil-up rate as well as the conventional variable, the volume remaining in the still-pot
Application of this procedure is illuatrated by evaluating operating strategies for batch distillation. A capacity factor is based on the time required to make a complete separation so that both the distillate product and the heel meet specific composition and disposition of a slop cut (if any) is accounted for. The reboiler is specified to operate at capacity but it is recognized that the boil-up rate will then drop off as the still-pot material becomes heavier and warmer. The distillate composition profiles and the boil up profiles are used to designate changes in objectives during the over-all runs.
Batch processing. The chemical processing industry has been using batch operations increasingly during recent years and these procedures have been drawing increasing attention in chemical engineering publications. Batch distillation is often selected as a significant purification in these processes and has likewise enjoyed a resurgence in investigations and reported advances and results.
Major companies have reported a broad use of batch processing. Chowdhury (1988) has reported that DuPont and Rohm and Haas operate numerous processing lines for hundreds of product variations. Professor G.V. Reklaitis of Purdue has developed a simulation program for designing, scheme selection, and scheduling batch processes and has founded a company, Batch Processing Technologies, Inc. to distribute results from his program.
Batch processing units are most often used in one of two ways. A sequence of equipment may be required to manufacture several different products. This method is often encountered when the products are based on various formulations and rely primarily on mixing and purification to meet customer requirements. Batch processing may also be specified when a particular product is produced from different raw materials and through various processing routes. In either case the same equipment is used repeatedly to perform similar but different operations and is scheduled to operate almost continuously by rapid turnarounds between functions to minimize downtime. 相似文献
Application of this procedure is illuatrated by evaluating operating strategies for batch distillation. A capacity factor is based on the time required to make a complete separation so that both the distillate product and the heel meet specific composition and disposition of a slop cut (if any) is accounted for. The reboiler is specified to operate at capacity but it is recognized that the boil-up rate will then drop off as the still-pot material becomes heavier and warmer. The distillate composition profiles and the boil up profiles are used to designate changes in objectives during the over-all runs.
Batch processing. The chemical processing industry has been using batch operations increasingly during recent years and these procedures have been drawing increasing attention in chemical engineering publications. Batch distillation is often selected as a significant purification in these processes and has likewise enjoyed a resurgence in investigations and reported advances and results.
Major companies have reported a broad use of batch processing. Chowdhury (1988) has reported that DuPont and Rohm and Haas operate numerous processing lines for hundreds of product variations. Professor G.V. Reklaitis of Purdue has developed a simulation program for designing, scheme selection, and scheduling batch processes and has founded a company, Batch Processing Technologies, Inc. to distribute results from his program.
Batch processing units are most often used in one of two ways. A sequence of equipment may be required to manufacture several different products. This method is often encountered when the products are based on various formulations and rely primarily on mixing and purification to meet customer requirements. Batch processing may also be specified when a particular product is produced from different raw materials and through various processing routes. In either case the same equipment is used repeatedly to perform similar but different operations and is scheduled to operate almost continuously by rapid turnarounds between functions to minimize downtime. 相似文献
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介绍两种适用于分批精馏及多用途填料塔的液体分布器——槽式和双排管式高弹性液体分布器。目前通用型液体分布器的操作弹性一般为4:1,而这种液体分布器,其操作弹性可达10:1左右。本文提出的小孔排量计算方法同样也适用于大型填料塔的液体分布器。 相似文献
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The distillation column dynamics is very nonlinear, especially at high purity. Multivariable control system designs, which are essentially linear, may not be able to perform well at different operating conditions. This paper looks at three different multivariable design techniques—decoupling control, optimal state feedback and pole assignment as applied to distillation column control. Robustness of these techniques are analyzed by looking at the performance of these controllers at different operating conditions. Some interesting results are obtained. 相似文献
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介绍了丙烯精馏系统传统设计流程及改进设计流程,并对其流程特点进行了分析,明确指出了各自的优缺点。针对改进设计双塔流程,利用流程模拟计算PRO-Ⅱ软件平台,分别研究了无中间再沸器和设置中间再沸器两个流程方案,在能耗相同的条件下,计算出不同塔盘数时的丙烯损失,并对其增加塔盘数后的可实施性、投资增加与多回收丙烯的经济性进行了初步分析。无中间再沸器流程在投资及年收益方面均优于设置中间再沸器流程,在装置急冷水热量充足的情况下,应首先推荐应用。 相似文献
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引 言在以往的研究中 ,间歇精馏塔的模型大部分建立在平衡模型的基础上[1] ,系统初值的选取基于伪热初始状态 ,即每层塔板上有足够的积液量 ,塔板温度在泡点温度以上的汽液平衡状态 .多数间歇精馏过程的仿真模拟软件中使用伪热状态作为初始状态[2 ] ,例如 ,HYSYS R○ (Hyprotech )、BATCHFRACTM (Aspentech )和CC -BATCH R○(CHEMCAD) .它们都是通过稳态和平衡计算为微分代数方程组提供了满足一致性要求的初始值 .间歇精馏过程的一个特点就是精馏塔频繁地从冷状态启动 ,初始状态会因再… 相似文献
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Michael D. Barrera Lawrence B. Evans M.A. Farrell Epstein Eng.Sc.D. 《Chemical Engineering Communications》1989,82(1):45-66
The economical design of continuous chemical processes to produce commodity products has reached an advanced state of development. Modern computer tools are used routinely to simulate and optimize these processes. This is not the case, however, for the manufacture of speciality products which must be made in batch operations. The continuing shift towards the production of higher value-added specialty products by the CPI has stimulated efforts aimed at developing good computer assisted design strategies for batch processes.
This paper discusses the formulation of the problem for the optimal design and operation of batch processes. The batch problem differs from the continuous one in a number of important ways. First, batch plants do not operate at steady state. There are important trade-offs between the processing time and the severity (intensity) of processing in single units. Cycle time and performance trade-offs also exist among the various units in the process. Second, batch plants produce multiple products in many cases. There is often a competition for shared resources (labor, utilities, and equipment) among the various products. This paper presents a hierarchical solution approach for the design and optimization of a batch process. The approach is demonstrated by solving an example problem which illustrates the fundamental economic trade-offs. 相似文献
This paper discusses the formulation of the problem for the optimal design and operation of batch processes. The batch problem differs from the continuous one in a number of important ways. First, batch plants do not operate at steady state. There are important trade-offs between the processing time and the severity (intensity) of processing in single units. Cycle time and performance trade-offs also exist among the various units in the process. Second, batch plants produce multiple products in many cases. There is often a competition for shared resources (labor, utilities, and equipment) among the various products. This paper presents a hierarchical solution approach for the design and optimization of a batch process. The approach is demonstrated by solving an example problem which illustrates the fundamental economic trade-offs. 相似文献
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引 言膜蒸馏是一项新型膜分离技术 ,具有常压低温操作、可利用废热等优点 ,受到越来越多研究者的重视[1] .可用于膜蒸馏的组件有多种 .从商业角度考虑 ,中空纤维膜及管式膜更具吸引力 ,因其单位体积设备可得到较大的膜面积 ,且能减轻极化现象的影响 .许多膜蒸馏研究工作中采用了中空纤维膜组件 ,Agashichev等求解了层流状态下的传热方程[2 ] ,Hogan等人将膜蒸馏与太阳能装置耦合 ,并通过换热系统回收部分热量 ,有效地提高了热效率[3] .但目前尚没有针对膜蒸馏设计的膜组件 ,膜蒸馏通常采用微滤膜组件 .而由于传热现象的影响… 相似文献
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引 言2 0世纪 80年代末 ,余国琮、杨志才等[1] 参照连续精馏开工过程的操作方法提出并实验证明了一种新的间歇精馏操作方法———塔顶累积全回流法(本文简称“全回流”) .采用此法 ,笔者[2 ] 最近推导出在理想操作条件下间歇精馏二元理想混合物精馏过程中塔顶贮槽内液体流动为完全混合时最小汽化总量计算法 .由于采用此法 ,塔顶贮槽内存液量可能很大 ,往往必须考虑塔顶贮槽内液体流动时的混合程度 .本文以多级串联混合模型的级数表示采用此操作方法塔顶贮槽内液体流动时的混合程度 ,以在理想操作条件下间歇精馏二元理想混合物为例 ,通过举… 相似文献