Abstract
Batch operation is the main production pattern for high value-added chemicals, and the wastewater from different batch production lines features differently in properties, such as contaminant concentrations, toxicity, pH, and chemical oxygen demand. Less attention has been drawn on the batch water network design with water property considered. To address this issue, this work develops a superstructure-based optimization approach to incorporate property integration within the synthesis of batch water network. Multiple production lines are considered in the study, so in addition to the water re-using system inside each production line, the re-using across lines and the central property treatment system are included by involving intermediate storage tanks as hubs for in-line, inter-line water allocation and treatment. The property treatment system is constructed by a list of property interceptors, which operate in semi-continuous manner with optimized treating performance in different time intervals. To obtain the desired network structure, a Mixed Integer Nonlinear Programming (MINLP) model is formulated, and the operation schedule of interceptors and storage tanks are optimized as well. Finally, a multi-property case is elaborated to validate the proposed method. By considering the potential interactions among batch production lines, a 22.12 % drop in Total Annual Cost (TAC) is achieved in the case study, demonstrating the effectiveness of the method.
