Research On Co-control Of Energy,Air Pollutants,and Water In The Iron And Steel Industry Of Beijing-Tianjin-Hebei Region

Jing-Jin-Ji region(Beijing-Tianjin-Hebei)faces triple pressures of global warming,regional air pollution,and water scarcity.Iron and steel industry,one of the main energy consumers,air pollutants emitters,and water consumers of this region,is confronted with great chanllenges on how to co-control of the three problems during its transformation and upgrading.Advanced technology is the key factor in transition to clean,low carbon and efficient sustainable development.To promote the adoption of energy-saving and emission-reduction technologies,the Chinese government has released serials of the National Extension Directory of Important Energy Conservation Technology.Thus,it is necessary to study how the iron and steel industry in the Beijing-Tianjin-Hebei region can co-control energy,air emissions,and water and toward sustainable development through technology transformation and upgrading.Based on previous related literatures,combing with the special constraints resources and environmental faced by Jing-Jin-Ji region,considering the key stage of transformation and upgrading of iron and steel industry,this thesis focused on the problem of co-control of energy,air pollutants,and water of iron and steel industry in Jing-Jin-Ji region.First,the energy consumption,air pollutants emissions,and water consumption per ton of steel production are estimated based on life cycle assessment to provide basis for optimizing steel production structure;secondly,environmental benefits assessment method are adopted to quantify the impact of each energy saving and emission reduction technology on energy,air pollutants and water resources and the technologies' cost-effectiveness are evaluated based on Conservation Supply Curve method,which lay foundation for optimal selection of technologies;Finally,based on the previous two parts of the study,the operational research theory and the bottom-up modeling method are used to establish a comprehensive dynamic optimization model to optimize the technological development path in order to achieve the purpose of co-control of energy,air pollutants and water.In the process of quantitative study,the following innovations are achieved.(1)Considering current technology status of the iron and steel industry in Jing-Jin-Ji region,an accounting model for CO2 and air pollutants(SO2,NOx,and PM2.5)emission is established.The CO2 and air pollutants(SO2,NOx,and PM2.5)emission and water consumption per ton of steel production of different iron and steel production routes are calculated from the perspective of life cycle.Blastfurnace-basic oxygen furnace(BF-BOF)route and electric furnace(EAF)steelmaking route are two common steelmaking routes.In the EAF steelmaking route,much hot iron is added,instead of scrap,to compensate for scrap shortage in China.To facilitate comparative analysis,the iron and steel production routes are divided into three types:BF-BOF route,hot iron and scrap based EAF route,and scrap based EAF route.The results show that compared with the BF-BOF route,the EAF route has lower CO2,SO2,NOx,and PM2.5 emissions per ton of steel production,but the water consumption per ton of steel production is higher.The water consumption per ton of steel production of the hot iron and scrap based EAF route is 63.45%higher than the BF-BOF route.The reason why the CO2,SO2,NOx,and PM2.5 emissions of hot iron and scrap based EAF route are too high is excessive hot iron utility.The CO2,and air pollutants(SO2,NOx,and PM2.5)emissions per ton of steel production of scrap based EAF route are obvious lower than the BF-BOF route and hot iron and scrap based EAF route.For example,the PM2.5 emission of scrap based EAF route per ton of steel production only account for 3.9%and 4.5%of the BF-BOF route and hot iron and scrap based EAF route,respectively.Thus,in the Beijing-Tianjin-Hebei region,the proportion of scrap based EAF route can be appropriately increased.(2)Based on the advanced energy saving and emission reduction technologies of iron and steel industry,the quantity of air emissions reduction and water savings of each energy conservation and emissions reduction technology are quantified;the traditional Conservation Supply.Curve model is expanded by incorporating environmental benefits of energy conservation technology,which aims to analysis how the environmental benefits impact the cost-effectiveness and priority of energy conservation tehnology.The results reflect that energy conservation technology can reduce CO2 and air pollutants in the energy buring process by saving energy,which can join reuduce CO2 and air pollutants emission from scouce.Besides,some energy conservation technologies also have water-saving effects.For example,technologies,such as coke dry quenching,have good energy conservation,emission reduction and water-saving effects.An obvious advantage of end-of-pipe(EOP)measures is that they have better reduction effects for a specific pollutant,however,they consume additional energy and water,which results in an increased generation of CO2 and water consumption.Therefore,energy conservation technologies,which can reduce air emissions from source,should be given priority in the technology selection process,especially to these with better synergistic effects.In addition to energy saving effects,energy conservation technologies also have multiple environmental effects,such as CO2 and air pollutants reductio,water-saving.However,these environmental effects of energy conservation technologies are often ignored by decision makers,especially in cost-benefit assessment.The research results show that taking these environmental benefits into the cost benefit assessment not only affect cost-effectiveness of energy conservation technologies,but also update the priority ranks of the technology choices.Therefore,it is of great significance to take environmental benefits into the cost-effectiveness assessment of energy conservation technologies,which contributes to selecting optimal technology combinations from a societal perspective.(3)The water factor is introduced into the coordinated control framework of CO2 and air pollutants.Considering the triple constraints of greenhouse gas emission reduction,severe air pollution and extreme shortage of water resources in the Beijing-Tianjin-Hebei region,and the complexity of the steel production process,a bottom-up comprehensive dynamic optimization model is established with the minimum cost as goal,to simulate the dynamic development process of technology and the interrelationship between multiple dimensions of technology,and explore the optimal technological development path for the steel industry in Beijing,Tianjin and Hebei to achieve coordinated control of energy,air pollutants and water resources.Considering the uncertainties of future technical costs,water supply and other parameters,a comprehensive dynamic optimization model with uncertainty parameters of investment cost and water availability is established based on the two-stage stochastic optimization method.This work makes up for the deficiency of two-stage stochastic optimization method on technology investment decision of iron and steel industry.Combing comprehensive dynamic optimization model with scenario analysis,the energy demand,air pollutants emission(SO2,NOx,and PM2.5),and water demand of iron and steel industry in the Jing-Jin-Ji region during 2015-2030 are predicted.The results show that in order to achieve the goal of co-control of enrgy,air pollutants,and water,26 technologies that present co-control effects on energy,SO2,NOx,PM2.5,and water,such as new type of high-thermal-conductivity and high-density silica brick in coke oven,small pellet sintering technology,and top-pressure recovery turbines(TRT)should be given priority in technology promotion to meet the comprehensive constraints of energy,air pollution,and water.The implementation of energy saving and emission reduction technologies and the increasing proportion of EAFs could potentially result in 321.11 million tons of energy conservation,3.07 million tons of SO2 reduction,1.08 million tons of NOx reduction,1.02-million tons of PM2.5 reduction,and 965 million cubic meters of water conservation by 2030.On one hand,this study provides a new perspective for decision makers to jointly control CO2,air pollutants,and water.On the other hand,it provides a technology roadmap for the establishment of a science and technology demonstration zone of energy saving,emissions reduction,and industrial transformation and upgrading of the iron and steel industry in the Jing-Jin-Ji region,and it also provides important guidance for the transformation and upgrading of China's iron and steel industry.