Multi-objective Sustainable Planning Of Chemical Production Chains

Sound management of chemicals is one of key contributors for achieving of the Sustainable Development Goals(SGDs).Facing the current development situation of the chemical sector,chemical industrial parks characterized by the accumulation of industrial space,rational allocation of production factors and the realization of intensive and sustainable development have become the mainstream of development at home and abroad.The question of how to properly plan the chemical production chains in the chemical industrial park at an early stage,and identify the final chemical products and the associated production routes,is of utmost importance.The aim of this work is to develop a multi-objective planning framework on the early planning and decisionmaking for chemical production processes,in order to obtain the maximum economic benefits,minimize the risk of possible chemical accidents to people,and minimize the environmental risk of production routes.In order to achieve this goal,this thesis will conduct a case study related to chemical production chains in the following three steps.The first step is to forecast the production of chemical products by building a GM(1,1)model.Using the production as an intermediate quantity,the relationship between year and price is established so as to forecast the price trend of chemical products from 2020 to 2030.The demand for the products and the price changes can provide a theoretical basis for reference in production practice.In the second step,the production chain of the industrial chemical park is evaluated,and three analytical indicators are defined:(1)economic index is expressed through added value;(2)safety index is evaluated in terms of the number of people affected by toxic and hazardous substances leaked in an accident;(3)The Environmental Index uses a hierarchical analysis model to determine the impact potential of chemical substances on the environment.The economic benefits,safety and environmental risks of the chemical product chain will be evaluated by these three indices.In the third step,the production process is simulated according to the chemical production network model,and a mixed integer linear programming(MILP)model is established by combining the three indicators of economic efficiency,safety and environmental risk with the production chain constraints.The differences of solution results under three scenarios will be explored and analyzed: single objective scenario,ε-constrained scenario and fuzzy optimization scenario.In the case study,the demand and price of PVC products for 2020-2030 are forecasted for the polyvinyl chloride(PVC)industry and the established framework is illustrated.The results of the single-objective scenario,the ε-constrained scenario and the fuzzy optimization scenario are compared.Carbon emissions of the two main production pathways are analyzed.The results of the fuzzy optimization scenario were found to meet the desired planning objectives,and the three indicators of economic,safety and environment could be traded off.Thus,a production chain was obtained in which propane was used as a raw material and ethylene was obtained by pyrolysis of propane;ethylene was generated by oxychlorination to 1,2-dichloroethane;vinyl chloride was then produced by dehydrochlorination of 1,2-dichloroethylene;and vinyl chloride was produced by ontogenic polymerization to PVC.