Integrated Assessment Of Exergy,energy And Carbon Dioxide Emission Reductions In An Iron And Steel Industrial Symbiotic Network

Fossil fuel consumption and pollutant emissions in many different industries around the world have caused problems to the resources and energy systems,in the economy,and the environment,especially global climate change caused by carbon dioxide?CO₂?emissions.Improving industrial system resources and energy efficiency,and reducing carbon dioxide emissions have become one of our major challenges.The concept of exergy has been widely applied to analyze processes of usage of resources and to investigate losses of energy quality from energy transformation.However,it is still difficult to assess availability of resources and energy,resources and energy efficiency,and related environmental impacts from using processes.The relationship between exergy and environmental impact is not clear,and there is also short of integrated assessment of exergy,energy,and carbon dioxide emission reductions in industrial symbiotic networks.First of all,this paper collected global data of energy consumption and CO₂ emissions to analyze relationship between CO₂ emissions and exergy losses which are from conversion of coal and nature gas,so as to build mathematical expressions of equivalent CO₂ emission potentials related to useful work from combustion of coal and nature gas.Thus,we determined link between exergy losses and environmental impacts.Secondly,we used an iron and steel industrial symbiotic network as research object to have an integrated assessment of exergy,energy and CO₂ emission reductions.Exergy efficiency and energy efficiency were used to analyze quality losses of energy conversion and performance of whole industrial symbiotic network.According to equivalent CO₂ emission potentials equations of coal and nature gas,we had the international average level of CO₂ emissions.This average emission level was used to compare actual emissions to calculate emission reduction potential.The results show that the sinter strand needs to be greatly improved and the wet quenching process needs to completely redesigned.The overall efficiency and energy efficiency can be improved by adopting industrial symbiosis measures.We found that adjusting the energy structure to use renewable energy and recycling solid waste can greatly reduce CO₂ emissions.Moreover,the maximum exergy losses occurred in the blast furnace with the maximum CO₂ emissions.We calculated CO₂ emissions caused by exergy losses from energy transformation of industrial symbiotic network through equivalent CO₂ emission potentials equations of coal and nature gas.Comparing with actual emissions of network,we found that emissions of iron making plant,steel making plant rolling plant and thermal power plant are higher than international average level of emissions.It is indicated that the future deployment of energy saving and emission reduction measures needs focusing on these four plants and there also needs improve processes to have higher energy conversion efficiency.