Study On Environmental Impact Assessment And Green Development Of Typical Steel Enterprises Based On Life Cycle Assessment

Iron and steel industry is a typical energy-intensive and high pollutant emitting industry in China.China's crude steel production is the largest in the world,and it reached 928 Mt in 2018,accounting for 51%of the world's crude steel output.In 2015,the iron and steel industry accounted for approximately 15%of China's total energy consumption and released 1,533 Mt of CO₂,accounting for 15.4%of the total CO₂ emissions.In 2018,88%of the crude steel manufactured in China was produced by blast furnace-basic oxygen furnace?BF-BOF?route.This leads to high energy consumption and greenhouse gas emissions in China's iron and steel industry.Therefore,it is necessary to analyze the life cycle of steel enterprises and explore their green development path.Firstly,GaBi v.8.7 software was used in this study to establish the life cycle list of typical steel enterprises covering bf-bof and EAF,and eight impact categories were evaluated,including Human Toxicity Potential?HTP?,Terrestrial Eco-Toxicity Potential?TETP?,Acidification Potential?AP?,Photochemical Ozone Creation Potential?POCP?,Global Warming Potential?GWP?,Eutrophication Potential?EP?,Abiotic Depletion Potential?ADP?,and Cumulative Energy Demand?CED?.Secondly,direct/indirect emissions from steel production are discussed,and the environmental impacts of two typical routes are analyzed.Finally,this research is also equipped with three production scenarios used to study:scenario 1?existing conditions?,scenario 2?replacement of coke and anthracite in BF with charcoal?,scenario 3?increase electric arc furnace?EAF?route?,so as to provide scientific reference for steel enterprises and explore the green development approach of the steel industry.The main conclusions are as follows:?1?The proportion of blast furnace units is the highest in almost every environmental impact category,and the normalization results also show that the overall impact of blast furnace is the largest,among which,GWP?40%?has the largest impact on the environment,followed by ADP?35%?and HTP?17%?.Throughout the steel process,the HTP category accounted for 33%of the seven evaluation categories studied,followed by GWP?30%?and ADP?25%?.?2?Among the direct/indirect contributions of each process,this study found that the use of coke in iron making was an important cause of environmental pollution.For HTP,the indirect contribution accounted for almost all the impact contribution,while for GWP,the direct contribution was far greater than the indirect contribution.In terms of indirect contributions,the two main causes of global warming are electricity and coke consumption.Secondly,by comparing the environmental impacts of BF-BOF and EAF production routes,the impact assessment categories all indicate that the use of arc furnace is better in environmental protection.For GWP contribution,EAF route is only 32%of BF-BOF route,and for CED energy data,EAF is 27%of bf-bof,because it avoids the use of a large amount of fossil energy.For HTP and TETP,it is mainly caused by a large amount of electricity consumed by EAF.?3?It is found that charcoal replace fossil energy and increase the proportion of electric furnace production can reduce the environmental impact.Scenario 2 could save 108 kg/t anthracite and 58kg/t coke,and the two energy impacts?ADP and CED?show a large reduction,and the global warming potential reduces by 454 kg of CO₂ eq?19%?.For scenario 3,all the environmental impact categories except HTP and TETP showed significant improvement,and CED?43%?,ADP?45%?,and GWP?40%?could achieve more than 40%reduction compared with scenario 1.Finally,the normalized data of the environmental impact assessment results show that the total environmental impact of scenario 2 and scenario 3 is reduced by 14%and 25%,respectively,compared with that of scenario 1.