Life Cycle Assessment Of Carbon Disulfide Production

As an important chemical raw material,the market demand of carbon disulfide is increasing year by year,and China is a major producer and consumer of carbon disulfide,therefore,as a high pollution and high energy consumption of carbon disulfide industry,the environmental problems faced by it cannot be ignored.This paper adopts a life cycle assessment approach to evaluate the environmental impact of carbon disulfide process from the upstream stage of raw material acquisition,and then proposes rationalized recommendations for cleaner production of carbon disulfide.In this study,Ga Bi v.9.2 software was used to develop life cycle models for two typical carbon disulfide production processes of natural gas method and coke continuous method,and the functional unit: one ton of fine carbon disulfide was selected,and eight environmental impact types were selected for analysis and evaluation: human toxicity potential(HTP),terrestrial ecotoxicity potential(TETP),acidification potential(AP),photochemical ozone production potential(POCP),global warming potential(GWP),eutrophication potential(EP),abiotic depletion potential(ADP),and freshwater aquatic ecotoxicity potential(FAETP).Main research contents:(1)analyze the amount of environmental contribution of each reaction unit and the main environmental types of each reaction unit;(2)classify the impact for the main single environmental impact type and analyze the contribution of each energy substance;(3)further analyze the overall impact of each energy substance on the environment based on the classification results of the single environmental impact type;(4)compare the two processes,analyze which process has a(4)compare the two processes,analyze which process has less impact on the environment,and compare their advantages and disadvantages in terms of environmental impact;(5)combine the above analysis results,explore the sustainable development of the enterprise from the perspective of clean production and put forward reasonable suggestions.The main conclusions are as follows.(1)Environmental contribution of each reaction unit: order of environmental contribution in the coke continuous method: molten sulfur stage ?drying and carbon preparation ?reaction and sulfur capture ?desulfurization stage ?Kraus process?distillation stage.The order of environmental contribution in the natural gas method: molten sulfur stage ? desulfurization stage ? natural gas pressurization ? reaction and sulfur capture ? Krauss process ? distillation stage.The normalized results show that the main environmental impact types in each reaction unit of both processes are: ADP,GWP,HTP,and AP.(2)Classification of the main single environmental impact type contribution.In the coke continuous method,in ADP,GWP: sulfur ? coke ? natural gas ? electricity;in HTP: sulfur ? electricity ? coke ? natural gas;in AP: sulfur ? other ? electricity ? coke ? natural gas.In the natural gas method: for ADP,HTP,and AP sulfur contributes the largest percentage.For GWP,ammonia contributes the largest percentage.The type of environmental impact of electricity is mainly in HTP,and other types of pollutants contribute significantly to the type of AP.(3)Analysis of the overall environmental impact of key substances: The overall environmental contribution of substances in the coke continuous method: sulfur ? coke ? natural gas ? electricity ? ammonia.Among them,coke contributes to the overall environment in the following order: ADP?GWP?HTP?AP?POCP?EP,and has less influence on FAETP and TETP types.In the natural gas process,the overall environmental contribution of substances: sulfur ? natural gas ? ammonia ? electricity,and the order of the overall environmental impact of natural gas: ADP?GWP?HTP?POCP?AP,with insignificant contribution to EP,FAETP and TETP.The order of contribution of the main substance sulfur in both processes: ADP?HTP?AP?GWP?POCP?FAETP,and insignificant contribution to EP and TETP.(4)By comparing the environmental impact of the coke continuous process with the natural gas process route,all the evaluated categories except FAETP showed that the coke continuous process did better in terms of overall contribution to environmental impact.For the GWP type impact aspect it is most obvious that the coke continuous process is only 55% of the natural gas method production process.This is followed by the contribution of EP,where the coke continuous process is 56% of the natural gas process.In terms of the ADP type,which has the largest impact type in the above analysis,the coke continuous process is also only 73% of the natural gas method,while in terms of AP,HTP,and POCP,the advantage is not obvious.