Assessing the chlorine metabolism and its resource efficiency in chlor-alkali industrial symbiosis - A case of Shanghai Chemical Industry Park

Abstract

As an important part of China's chemical industry, chlor-alkali enterprises were featured by heavy consumption of natural resource and large amount of pollutants. Circular economy in chlor-alkali industry should be developed in China to achieve a balance between economic growth and resource consumption. This study took three chlor-alkali enterprises in Shanghai Chemical Industry Park as a case, and three scenarios were established for chlorine metabolism: Scenario 1 (Chlorine flows independently), Scenario 2 (Chlorine flows from Enterprise A to Enterprise B and C), Scenario 3 (Closed loop of Chlorine Gas). An integrated methodology based upon Substance Flow Analysis (SFA), Life Cycle Assessment (LCA), Life Cycle Cost (LCC), and Data Envelopment Analysis (DEA) was set up and used to evaluate the Chlor-Alkali Industrial Symbiosis. The results showed that the resource efficiency, production and conversion rate of chlorine was significantly improved with the establishment and optimization of symbiosis scenarios, which also showed very positive environmental and economic benefits according to LCA-LCC analysis. DEA was performed to analyze the Chlorine's resource efficiency in its metabolism, and the results showed that the efficiency of Scenario 1, Scenario 2 and Scenario 3 were 0.8548, 0.9490 and 1, respectively. Especially, in Scenario 3, a new chemical technology, catalytic oxidation of hydrogen chloride, can convert the by-product hydrogen chloride into chlorine, which can be reused and finally made a closed-loop in this industrial symbiosis. The results of this study can provide a new way to optimize the resource recycle, pollutants discharge and carbon emissions of chlor-alkali industry.