應用數學規劃法作批次製程質/能交換器網路之合成與設計

本論文旨在以數學規劃法分別探討批次製程中的質/能整合問題。在不考慮生產排程問題的前題之下，雖然批次製程的生產週期及各程序流體的起始與結束時間均為已知，但流體的存續時間仍為設計批次製程網路的主要困難。此，相對於連續製程的質/能整合問題，在整合批次製程工廠中各程序流體之物質或能量時，除了濃度/溫度等限制條件依然必須考量之外，常必須藉由另行設置儲存槽的方式以暫存多餘的堪用流體，待與後續流體有整合的機會時再依需求釋出，以克服各程序流體的存續時間常有落差的限制。論文的第一部份首先探討批次製程的質量整合問題。為了充分發揮數學規劃法的特點，也就是可先考量到所有可能狀況再整併出可行的最佳設計。本研究依據給定的生產週期及各程序流體的起始與結束時間，將整個批次製程生產週期區隔為數個操作區段。如此，個別操作區段內的質量整合問題均可視同連續製程的質量整合問題。本研究提出一個包括暫存槽且考量到所有操作可能性的質量交換器網路超結構，其中分別討論間歇性操作和連續性操作的質量交換網路。兩類操作模式的最佳網路合成問題都可基於最小化額外貧流之消耗或總年度成本為目標，分別制定為混合整數非線性規劃。最後再以一個文獻中的焦媒爐氣體的淨化問題為例，用以驗證對半連續程序所提出之質量網路結構整合方法的適用性。本論文的第二個部分為針對批次工廠中間接熱能交換網路之合成與其能量儲存策略，提出一個能描述廣泛使用狀況的熱能交換器網路超結構。首先使用一個原本存在於低溫槽的熱能轉移介質去吸收熱流中過剩的熱量，並且將已升高溫度的熱能轉移介質隨後暫時地存放在高溫儲槽中。其已累積相當熱能的熱能轉移介質隨後被使用在加熱後續的程序冷流，之後已被冷卻的熱能轉移介質將返回到原本的低溫儲槽中。藉由反覆循環在儲存槽間的熱能轉移介質，在批次工廠中與時間相關的熱/冷流的熱能交換限制因此可以被放寬，其中，儲存槽並包含兩種類型，即固定溫度/可變化質量之熱能儲存槽與可變化溫度/可變化質量之熱能儲存槽。依據所提出的熱能交換網路超結構，以最小化公用能源消耗與年度成本為設計目標，可分別制定兩個混合整數非線性規劃來描述使用不同類型熱儲存槽之間接性熱能交換網路合成問題。最後，採用一數值例子來比較狹點分析/設計和所提之方法所得結果，並用兩個較複雜的程序驗證所提出的間接式熱能合成方法之適用性。

關鍵字

批次程序；合成；質量交換器網路；能量交換器網路；超結構；混合整數非線性規劃

並列摘要

This dissertation aims to confer the mass and heat integrated problems in batch processes by mathematical programming. Under the situation that does not consider the problem of production scheduling, although the production cycle and starting and ending times of each process stream in batch processes are both known, the existing time of streams is still the main difficulty for designing the networks in the batch processes. Hence, comparing with the mass and heat integrated problems in continuous processes, besides considering the composition/temperature limitation for synthesis the material or energy of process streams in batch plants, storage tanks are often used to overcome the constraint, the drop of the existing times for process streams. The first part in this dissertation is to analyze the mass exchange network synthesis problem in batch processes. To exhibit amply the mathematical programming feature that is to ponder all possible conditions first and then to merge the feasible optimized design, the entire production cycle of batch process is divided into several operating periods according the given of production cycle and starting and ending times of each process. Therefore, the mass exchange network synthesis problem within each operating period resembles the mass integration problem of continuous process. This research presents a superstructure including storage tanks and mass exchange network (MEN) for all possible operations, where the mass exchange network is operating in intermittent and the continuous modes. The synthesis problems of two operating modes are formulated as mixed-integer nonlinear programs (MINLPs) based on the objectives of minimizing the external mass separating agents (MSAs) or the total annual cost (TAC). Finally, a coke oven gases (COGs) purification problem from the literature is used to demonstrate the applicability of the proposed MEN synthesis method for semi-continuous processes. The second part in this dissertation aims at proposing a generic superstructure of a heat exchange network (HEN) focusing on indirect heat integration and its associated thermal storage policy. The thermal storage uses a heat transfer medium (HTM) that initiated in a cold tank. It is then sent to absorb surplus heat from hot process streams and results at an elevated temperature, before it is to be temporarily stored in a hot tank. The accumulated hot HTM is then utilized to heat subsequent cold process streams, and the cooled HTM is circulated back into its source cold tank. By applying the re-circulated HTM storing in indirect thermal storages, the limitation of heat interchange between time-dependent hot/cold process streams in batch plants can be relaxed. The heat storage system consist of two types, the fixed temperature/variable-mass (FTVM) heat storage and the variable-temperature/variable-mass (VTVM) heat storage. Based on the proposed heat exchange network superstructure, the synthesis problems of indirect HENs for different types of thermal storages are formulated as two MINLPs, where the objective is to minimize the utility consumption and the total annual cost. One numerical example are analyzed to compare results from the pinch analysis technique and the newly proposed methods, and two complex processes are used to demonstrate the applicability of proposed indirect heat integration synthesis method.

並列關鍵字

Batch process ； Synthesis ； Mass exchange network (MEN) ； Heat exchange network (HEN) ； Superstructure ； Mixed-integer nonlinear programming (MINLP)

參考文獻

[3] Foo, C. Y.; Manan, Z. A.; Yunus, R. M.; Aziz, R. A. Synthesis of mass exchange network for batch processes- part i: utility targeting. Chem. Eng. Sci. 59, 1009-1026

[6] El-Halwagi, M. M.; Manousiouthakis, V. Synthesis of mass exchange networks. AIChE J. 35, 1233-1244 (1989).

[7] Gremouti, I. D. Integration of batch processes for energy savings and debottlenecking. Master's thesis, Department of Chemical Engineering, University of Manchester Institute of Science and Technology (UMIST), U. K. (1991).

[8] Foo, C. Y.; Manan, Z. A.; Yunus, R. M.; Aziz, R. A. Synthesis of mass exchange network for batch processes - part ii: minimum units target and batch network design.

Chem. Eng. Sci. 60, 1349-1362 (2005).

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應用數學規劃法作批次製程質/能交換器網路之合成與設計

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