共查询到20条相似文献,搜索用时 15 毫秒
1.
Mass and heat are very important resources in the process industry. Numerous approaches have been proposed for the optimization of either mass or heat exchange networks. Since the process usage of mass and heat is typically intertwined, it is important to account for such interactions. The objective of this paper is to introduce a systematic method for the simultaneous synthesis of combined mass- and heat-exchange networks (CMAHENs). The proposed method is based on a novel approach that incorporates the mass pinch technology (MPT) for mass exchange networks (MENs) synthesis and the pseudo-T-H diagram approach (PTHDA) for the heat exchange networks (HENs) synthesis. New bypass streams are included in the structural representation of the problem to expand the search space. A combined optimization approach is applied to minimize the total annualized cost of the CMAHEN. Finally, two cases are solved to illustrate the application of the proposed method. 相似文献
2.
The multipass heat exchanger is the most common type of heat transfer equipment used in heat exchanger networks (HENs) by the chemical process industries. There are many methods that have been proposed for the synthesis of HENs with multipass heat exchangers, which are mostly derived from the FT design method. In this paper, an alternative new method to synthesis multipass HENs is presented based on the classical pinch technology. In the multipass heat exchanger, both countercurrent and co-current flow are involved. For the co-current flow, composite curves and problem tables are modified, and compared with that of the countercurrent flow. A proper minimum temperature difference is also selected considering the energy-capital cost trade-offs, and then a multipass HEN is synthesized. Results of the case study demonstrate that the new approach meets operating requirements and minimizes the total cost successfully. 相似文献
3.
Ziyatdinov N. N. Emel’yanov I. I. Lapteva T. V. Ryzhova A. A. Ignat’ev A. N. 《Theoretical Foundations of Chemical Engineering》2020,54(2):258-276
Theoretical Foundations of Chemical Engineering - A new approach to the synthesis of a multistage heat exchange network is proposed based on the principle of fixation of variables. This principle... 相似文献
4.
For the optimal design of a heat exchanger network, the inlet and outlet stream temperatures of each heat exchanger in the network should be known. An explicit analytical solution of stream temperatures of an arbitrary connected heat exchanger network was introduced, which is suitable for the thermal calculation of heat exchanger networks. For the heat exchanger network synthesis, this solution was further developed and coupled with the stage-wise superstructure heat exchanger networks. The new calculation procedure reduced the computer memory requirement dramatically. On the basis of this solution, a mathematical model for synthesis of heat exchanger networks with genetic algorithm was formulated, which is always feasible and no iteration is needed. Two examples were calculated with the proposed approach and better results were obtained. 相似文献
5.
A new approach is developed to perform mathematical modeling of heat transfer with consideration of deformation of a physical system in a chemical reaction zone. This approach describes boundary conditions using fractional differential-integral calculus. A numerical analysis using the model proposed is undertaken to examine processes during nonlinear heat transfer accompanied by deformation of a physical system due to intense gas release in chemical reactions, particularly in processes of the production of materials by self-propagating high-temperature synthesis. 相似文献
6.
用遗传算法进行多流股换热器网络综合的研究 总被引:7,自引:0,他引:7
建立了多流股换热器网络综合数学模型,该模型改进了文献中等温混合的不合理假设。多流股换热器网络综合问题本质上是一个混合整数非线性规划问题(MINLP),这类问题的非凸非线性的特性使得目标函数存在多个局部最优解。传统的基于梯度的搜索方法在处理这类问题时由于计算规模庞大且极易陷于局部最优解而不再适用,而遗传算法却为解决这类问题提供了很有希望的一个方向。因而对遗传算法求解多流股换热器网络综合问题进行了研究,提出了可以自动产生可行的多流股换热器网络的方法策略,最后通过两个例题说明所提方法是可行的。 相似文献
7.
An algorithmic-evolutionary approach for the synthesis of heat exchanger networks is proposed. This approach is based on searching and breaking all heat load loops in the initial network. The method can effectively minimize the number of heat transfer units in an existing network without increasing its utility consumption above the minimum thermodynamic requirement. 相似文献
8.
用伪并行遗传/模拟退火算法进行多流股换热器网络综合的研究 总被引:4,自引:0,他引:4
The multi-stream heat exchanger network synthesis (HENS) problem can be formulated as a mixed integer nonlinear programming model according to Yee et al. Its nonconvexity nature leads to existence of more than one optimum and computational difficulty for traditional algorithms to find the global optimum. Compared with deterministic algorithms, evolutionary computation provides a promising approach to tackle this problem. In this paper, a mathematical model of multi-stream heat exchangers network synthesis problem is setup. Different from the assumption of isothermal mixing of stream splits and thus linearity constraints of Yee et al., non-isothermal mixing is supported. As a consequence, nonlinear constraints are resulted and nonconvexity of the objective function is added. To solve the mathematical model, an algorithm named GA/SA (parallel genetic/simulated annealing algorithm) is detailed for application to the multi-stream heat exchanger network synthesis problem. The performance of the proposed approach is demonstrated with three examples and the obtained solutions indicate the presented approach is effective for multi-stream HENS. 相似文献
9.
An interval based superstructure approach for combining the synthesis of heat and mass exchanger networks is presented in this paper. The technique involves combining the interval based MINLP superstructure (IBMS) for the synthesis of heat exchanger networks (HENs) with that of mass exchanger networks (MENs). The two networks are made to interact through the lean stream in the mass exchange network. The new approach involves the use of the lean substream concept to explore potential mass exchange temperatures. An example which involves a one-lean stream mass exchange problem alongside regeneration and hot and cold utilities is presented. 相似文献
10.
Pressure drop and fouling are important issues in heat exchanger network synthesis, which are usually neglected. Heat exchangers were designed in detail during the heat exchanger network synthesis, and pressure drop and fouling effects were taken into account. Pinch analysis combined with exergoeconomic analysis was used for determining optimal minimum approach temperature (ΔTmin) for heat exchanger network synthesis. Exergy consumption of heat transfer in HENs was calculated using a subsection integral on balanced composite curves. The heat transfer coefficients of all heat exchangers in the network were calculated iteratively to meet the requirements of optimal area and allowable pressure drops. The proposed method was applied to an industrial case. Numerical results indicate the importance of the detailed design of heat exchangers in HENs synthesis. 相似文献
11.
A thermoeconomic approach to the systematic evolutionary synthesis of energy-optimum and minimum-cost, heal exchanger networks is presented. The proposed approach can be applied by simple hand calculations and graphical manipulations to synthesis problems represented by either heat content diagrams or temperature interval diagrams. Applications of the approach have successfully generated optimum and suboptimum networks of five to ten process streams with much less time and effort compared to previous studies. It is shown that final networks for example synthesis problems can be obtained without performing cost evaluations of intermediate networks during the evolutionary synthesis. 相似文献
12.
This article presents a simulated annealing-based approach to the optimal synthesis of distillation column considering intermediate heat exchangers arrangements. T-he number of intermediate condensers and/or intermediate reboilers, the placement locations, the.operating pressure of column, and the heat duties of intermediate heat exchangers are treated as optimization variables. A novel coding procedure making use of an integer number series is proposed to represent and manipulate the structure of system and a stage-to-stage method is used for column design and cost calculation. With the representation procedure, the synthesis problem is formulated as a mixed integer nonlinear programming (MINLP) problem, which can then be solved with an improved simulated annealing algorithm. Two examples are illustrated to show the effectiveness of the suggested approach. 相似文献
13.
14.
Zhaoyi Huo Liang Zhao Hongchao Yin Jianxiong Ye 《Korean Journal of Chemical Engineering》2012,29(10):1298-1309
The heat exchanger network synthesis problem often leads to large-scale non-convex mixed integer nonlinear programming formulations that contain many discrete and continuous variables, as well as nonlinear objective function or nonlinear constraints. In this paper, a novel method consisting of genetic algorithm and particle swarm optimization algorithm is proposed for simultaneous synthesis problem of heat exchanger networks. The simultaneous synthesis problem is solved in the following two levels: in the upper level, the network structures are generated randomly and reproduced using genetic algorithm; and in the lower level, heat load of units and stream-split heat flows are optimized through particle swarm optimization algorithm. The proposed approach is tested on four benchmark problems, and the obtained solutions are compared with those published in previous literature. The results of this study prove that the presented method is effective in obtaining the approximate optimal network with minimum total annual cost as performance index. 相似文献
15.
Simultaneous synthesis of distillation sequences in overall process schemes using an improved minlp approach 总被引:2,自引:0,他引:2
This paper describes the synthesis of distillation sequences simultaneously with the synthesis of other process subsystems. An improved MINLP approach is proposed for the synthesis of complex problems. The improvements were made on three major MINLP levels. By postulating the superstructures we propose to use smaller and more compact superstructures of the distillation sequences included in the flowsheet superstructure rather than the usual tree and network representations. In the modelling step a higher degree of simultaneity has been accomplished by the use of simultaneous models of the distillation column and aggregated models of other process units. To facilitate the optimization phase the modified OA/ER algorithm [Kravanja and Grossmann, Ind. Engng. Chem. Res.26, 1869–1880 (1994)], implemented in the computerized synthesizer PROSYN-MINLP, has been used to reduce the effect of nonconvexities. Also, a special initialization and linearization scheme for simultaneous synthesis of HEN has been proposed. The improved method is illustrated by the synthesis of the separation subsystem followed by the simultaneous synthesis of the heat integrated separation system and its heat exchanger network (HEN). Finally, the optimization of the overall process and the simultaneous synthesis of its distillation system and heat integrated HEN is presented. 相似文献
16.
17.
Based on the pinch point method and a modification of the fast algorithm a new combined strategy is proposed for completing the synthesis of heat-exchange networks. To avoid the violation of minimum energy consumption and the assignment of overcomplicated structures, two new types of pinch situation (hidden and pseudo pinches) are distinguished and two new rules suggested. The total allowable heat load, determined iteratively, assures minimum energy consumption. The minimum heat load, as an arbitrary parameter, limits the exchangers' size and thus avoids the synthesis of overparcelled countercurrent cascades (too many, small, exchangers). The synthesis of heat-exchange networks is further improved by applying direct relaxation of the pinch principle (neglecting the pinch temperature) when the heating or cooling demand of the residue of a stream after a match is less than the minimum heat load. The structures and results of the computer program elaborated according to the new strategy proved to be quite reasonable for industrial problems. 相似文献
18.
Lealon L. Martin 《Chemical engineering science》2003,58(18):4291-4305
This paper demonstrates the use of the Infinite DimEnsionAl State space (IDEAS) approach in synthesizing optimal power cycles featuring minimum heat exchange area. IDEAS is used to synthesize power cycle networks which include splitters, mixers, pumps, turbines, and heat exchangers and feature a single or multiple working fluid(s). The overall synthesis goal is to minimize heat exchange area requirements, while delivering a fixed percentage of the maximum net power obtainable from a given set of hot and cold utilities. The global optimality of the obtained power cycle network configuration is guaranteed, since IDEAS gives rise to convex (linear) programs. The power of the proposed approach is demonstrated on a case study involving the generation of electricity by a bottoming cycle with a pure ammonia working fluid. Real thermodynamic data for pure ammonia and rigorous equipment models are employed in carrying out the proposed optimization. 相似文献
19.
提出在柔性换热器网络设计时考虑设备投入运行后实施在线清洗时序安排的同步优化方法,实现换热器网络动态综合。为降低该问题计算的复杂性,提出采用两阶段法。第一阶段利用虚拟温-焓图法初步综合获得考虑设备结垢过程和流股入口温度、热容流率发生变化时的多周期柔性网络,在同步优化之前识别出较优匹配候选。第二阶段,换热网络结构、设备面积和清洗时序安排利用遗传/模拟退火算法进行同步优化。通过积分方法来计算随时间变化的公用工程消耗,所建立的数学模型因此比以往文献更加严格。计算实例表明,所提方法有效降低年度总费用,同时能够解决大规模柔性换热器网络综合问题。 相似文献
20.
基于群体智能算法的换热网络同步最优综合 总被引:4,自引:4,他引:0
换热网络同步综合方法一般需要建立复杂的混合整数非线性数学规划模型,该模型具有非凸、非线、不连续的特点,属于最难求解的一类NP-hard问题,应用传统的优化算法很难确定其全局最优解,尤其是对大规模换热网络综合问题,甚至无法在合理时间内接近全局最优的局部最优解。针对换热网络同步综合问题,提出基于群体智能算法的分层优化策略,外层采用离散粒子群算法与遗传算法相结合的混合群体智能算法优化换热网络结构,内层在结构变量给定条件下利用改进粒子群算法优化冷热物流分流比与换热负荷。两个典型算例研究证明了该方法能以较高的效率和稳定性得到较好的优化结果。 相似文献