Screening models for batch process development are applied to several case studies. Two different processes are examined, and the targeting models derived for the reaction tasks illustrate the ability of screening mod...
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Screening models for batch process development are applied to several case studies. Two different processes are examined, and the targeting models derived for the reaction tasks illustrate the ability of screening models to employ information that is commonly available early in process development to perform aspects of the process synthesis. Bounds for the extents and selectivity of reaction are derived in terms of key operating variables. The first process demonstrates the ability of the screening models to identify favorable processing structures and illustrates the need to consider a rich enough set of processing configurations when generating the process superstructure. The application of the screening models to an industrial siloxane monomer process demonstrates the ability of the screening models to identify favorable processing structures early in the design of a real-world example process, and illustrates how the screening models facilitate the dynamic optimization of particular process structures. (C) 1999 Elsevier Science Ltd. All rights reserved.
Screening formulations for batch process development are introduced. Screening models bound the dynamic performance of batch distillation and reaction tasks with algebraic models. The discrete design decisions related...
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Screening formulations for batch process development are introduced. Screening models bound the dynamic performance of batch distillation and reaction tasks with algebraic models. The discrete design decisions related to the structure of the processing network and the assignment of equipment are considered simultaneously with the dynamic decisions concerning the operating policies of the tasks within a convex mixed-integer model that yields a rigorous lower bound on the cost of the design. These formulations not only provide design targets to measure the potential for improving existing designs, but also perform aspects of the process synthesis such as selection of separation structures and solvents from a list of candidates. The derivation of the screening models and the way in which they can be used to enhance existing techniques for batch process development are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.
The design of an industrial water system, which makes the most efficient use of the water resources available, is a complex problem that involves different trade-offs. If we assume that no fundamental process changes ...
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The design of an industrial water system, which makes the most efficient use of the water resources available, is a complex problem that involves different trade-offs. If we assume that no fundamental process changes can be performed (i.e. wet cooling towers cannot be replaced by air-coolers, etc.), then we can improve the efficiency of the water system through practices as water re-use, regeneration of water prior to re-use, or regeneration and recycling. The inherent combinatorial nature of the problem calls for the development of a systematic methodology that can deal with the high dimensionality of the design problem. In this paper we propose an integrated methodology for the design of industrial water systems. This approach brings the engineering insights provided by the water-pinch analysis together with powerful mathematical programming tools. The method is based on a decomposition scheme for the optimisation of a superstructure model that includes all the possible features of a design. The proposed decomposition strategy is based on a recursive procedure. With this new approach, a network featuring minimum total annualised cost can be found where the complexity of the network structure is under the control of the designer and many practical constraints can be incorporated. (C) 1998 Elsevier Science Ltd. All rights reserved.
This paper reviews the basic terminology associated with process scheduling and planning problems, the technical issues underlying their formulation and solution, and the considerations associated with installing, sch...
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This paper reviews the basic terminology associated with process scheduling and planning problems, the technical issues underlying their formulation and solution, and the considerations associated with installing, scheduling and planning software. This review motivates a discussion of next generation scheduling and planning technology. Examples are provided to illustrate both basic applications, and to show the scope of industrial scale problems. (C) 1997 Elsevier Science Ltd.
Pitchmatching algorithms are widely used in layout environments where no grid constraints are imposed. However, realistic layouts include multiple grid constraints which facilitate the applications of automatic routin...
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Pitchmatching algorithms are widely used in layout environments where no grid constraints are imposed. However, realistic layouts include multiple grid constraints which facilitate the applications of automatic routing. Hence, pitchmatching algorithms should be extended to those realistic layouts. This paper formulates a pitchmatching problem with multiple grid constraints. An algorithm for solving this problem is constructed as an extension of conventional pitchmatching algorithms. The computational complexity is also discussed in comparison with a conventional naive algorithm. Finally, examples and application results to realistic layouts are presented.
An optimal planning problem of a co-generation plant is studied which is constructed by combining gas turbine generators, waste heat boilers, auxiliary boilers, etc. The planning problem proposed is to determine the o...
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An optimal planning problem of a co-generation plant is studied which is constructed by combining gas turbine generators, waste heat boilers, auxiliary boilers, etc. The planning problem proposed is to determine the optimal configuration of the plant equipment taking into account the optimal operational policy of the plant for the annual energy demands of electric power and heat given a priori . Based on the annual cost method, the long-term economics of the plant is evaluated by the annual total cost, which is the objective function to be minimized. This optimal planning problem is formulated as a mixed-integer linear programming problem, and the optimal solution is derived by adopting the branch and bound method. As a result, both the configuration of the plant equipment and the operational policy are optimally determined reflecting the difference in economics and efficiency of the scale of each equipment. In addition, both the power to be purchased and the value of maximum contract demand of the purchased power is optimally determined. Using a numerical example, the validity and effectiveness of the optimal planning method proposed here is ascertained.
The demand for electricity varies substantially from hour to hour, from day to day, and from season to season. Because electricity is a highly perishable commodity which can be stored only at great expense, and becaus...
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The demand for electricity varies substantially from hour to hour, from day to day, and from season to season. Because electricity is a highly perishable commodity which can be stored only at great expense, and because the penalty for failing to meet demand is severe, the fluctuations of demand over time are crucial in determining an optimal investment strategy for generating equipment. Traditionally, demand is represented by a load-duration curve which neglects the time of day when peaks and troughs occur. By incorporating a load-distribution curve into the model in a computationally tractable manner, this paper demonstrates that the results of the traditional models may be sensitive to changes in the assumptions implied by the load-duration curve. [ABSTRACT FROM AUTHOR]
This paper deals with an optimization problem for a system composed of continuous and discrete subsystems. The discrete subsystem is introduced to express a combinatorial constraint in conventional control problems. T...
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This paper deals with an optimization problem for a system composed of continuous and discrete subsystems. The discrete subsystem is introduced to express a combinatorial constraint in conventional control problems. The objective, the state equation and the constraint are assumed linear. Then, the problem is formulated as a mixed-integerlinear program with staircase structure. A feasible decomposition method is developed for obtaining a suboptimal solution of the problem. In applications to an optimal energy control and planning problem of a large-scale production Plant, the method gives a solution satisfying the condition that the number of switching times for the boiler operation is as small as possible.
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