Feasibility Analysis And Technology Choice For Water-Energy Conservation Synergy In The Iron And Steel Sector

As important resources for human living and development,the shortages of water and energy,which are closely correlated,have become two major threats to global sustainable development.However,for a long time,the water and energy management in industry are relatively independent.Industrial technology choice and policy decision usually focus on a single system,probably leading to tradeoffs in other systems.Especially for the iron and steel sector,although its production and development are challenged by the duel pressures of water and energy conservation,it is still unclear how to coordinate the demand and use of these two resources.This study constrcuted an integrated model by integrating multi-regional input-output model,input-output based life cycle assessment hybrid model,econometric methods,cost-benefit analysis and Monte Carlo simulation.Based on the integrated model,this study analyzed the feasible space and technology choice for water and energy conservation synergy in the iron and steel industry from both the demand side and the supply side.The analysis identified key nodes of water and energy conservation,assessed the feasibility of water-energy synergy and proposed a collaborative management strategy by updating technology choice list.The study will faciliate policy decisions on taking the advantages of water-energy synergies and getting rid of water-energy tradeoffs in the iron and steel sector.The results show that strong steel demand stimulates the industry’s consumption for water and energy.Affected by the capital formation,steel use and the assoicated water and energy consumption haven’t decoupled from economic development in the short term.A 1%increase of per capita GDP is associated with 2.3%increase of true steel use,2.8%increase of water consumption and 2.6%increase of energy consumption associated with true steel use.Such strong relationship determines that the feasibility of saving water and energy simultaneously by countrolling steel demand is limited in the short term.China is the key node of water and energy consumption in the global steel industry:in 2013,China accounted for 74%of the water consumption and 54%of the energy consumption in the global steel production.But 37%of the water consumption and 24%of the energy consumption serve the final demand of other countries.Focusing on China’s steel production,this study found that water-energy tradeoffs exist in the adjustment of the steel production process and the application of low temperature rolling technology.From the life cycle perspective,replacing the Blast Oxygen Furnace(BOF)steel making process with the Electric Arc Furnace(EAF)steel making process could save 13.2%-15.7%of embodied energy per ton of crude steel at the expenses of an additional 10.6%-16.4%water consumption;Employing the technology of low temperature rolling steel production can reduce the energy consumption of 9-17 kilograms of standard coal but need to consume more than 0.1-0.2 m~3 of water resources.In addition,this study identified 18 of energy-saving technologies which have water-saving co-benefits,including combined cycle power generation technology(CCPP),dry quenching technology,blast furnace gas pressure energy recovery turbine unit(TRT,dry)technology.These technologies can save more than 20 m~3 water per ton of standard coal of energy saving;Incorporating these associated water impacts into the life-cycle cost-benefit assessment,this study found that the energy saving cost decreased by$2-26 per ton of standard coal,and the cost-effective energy saving potential increased.Based on these results,the research updated the priority of technology choice and set up a list of energy-saving technologies with water-saving synergy.