應用數學規劃法設計含批式與連續式製程之跨廠區用水網路

Abstract

本文針對跨廠區水網路，提出以數學規劃法的方式進行整體最適化的設計，在些許的廠區內同時擁有批式與連續式的製程。 此論文針對整合這兩種製程提出兩種情況進而討論之。第一種是針對連續式製程為主的廠區，提出兩階段的構想。 首先將所有批式單元視為連續式操作，設計最小新鮮水消耗量的跨廠區水網路系統。而後去計算批式單元儲存桶的儲存流量， 達到最小化儲存桶的大小；第二種情況則是以批式製程為主的廠區。將連續式單元視為批式單元之特例， 而操作的起始與結束時間點分割是根據批式單元為定。 本研究以超結構為基礎建立數學模式，並利用此數學模式分析兩種不同的目標函數最小化新鮮水消耗量以及最小化儲存桶大小。 本論文所提出之方法皆經由不同的例子去說明。

This work presents a mathematical technique for the synthesis of inter-plant water network, where some of the plants involve batch and continuous processes. To integrate both kinds of process units, two scenarios are investigated. Scenario one is for continuous units in majority, a two-phase approach is proposed for this scenario. First, all batch units are treated as operating in continuous mode, and the inter-plant water network is synthesized for minimum fresh water consumption. Policy of water storage for these batch units is then determined, on which they can be operated as continuous units with the aids of a pair of input/output storage tanks for each batch unit. The objective of the second phase is to minimize the capacity of storage tanks subject to determined water flow rates. Scenario two is for batch units in majority, where each continuous unit is divided into a series of batch operating sections according to the start and end times of existing batch units. A batch water network with or without storage tanks is synthesized accordingly. The model formulation is based on superstructures, and the system is designed according to two objectives including the minimization of fresh water consumption and the minimization of storage tank size. Illustrative examples are supplied to demonstrate the applicability of proposed schemes for inter-plant water network synthesis.