Analysis Of Energy Saving And Emission Reduction Potential Of Steel-Cement-Power Polygeneration System

Since the reform and opening up,China’s industrialization development has made world-renowned achievements,but the current "high investment,high consumption,high pollution,low efficiency,and low output" development model of China’s industry has not been fundamentally improved.Accelerating the construction of ecological civilization in the industrial field and guiding the industry to change to a green direction have become a national development strategy.The purpose of this article is to analyze the energy conservation and emission reduction potential of C hina’s key energy-consuming industries by establishing a multi-generation system framework with utilization of solid waste,product structure adjustment,energy consumption and carbon emissions during production as the linkage points.First of all,a detailed analysis was made of the production processes,energy consumption,carbon emissions,and the discharge and utilization pathways of solid waste in the steel,cement,and power industries.Based on this,a multi-generation system-is designed and established,which uses solid waste resources such as blast furnace slag and fly ash as ecological connections.The dynamic material flow analysis method is applied to the steel-cement industry,and through the bottom-up method,the production forecast model is established through the analysis of the life distribution,demand and output of products in various downstream industries.The results show that China’s cement output reached a peak of 2492.07 Mt in 2014.It was in a state of dynamic equilibrium from 2013 to 2025,followed by a significant downward trend from 2025 to 2050,until it fell to 1522 Mt in 2050,and then gradually stable.The life of downstream products has a great impact on cement demand,but it will not change the time when cement demand reaches its peak.China’s steel demand has also peaked and will continue to decline in the future,until it drops to 440.38Mt in 2043,after which it will stabilize from 2045.According to the regional power demand,China’s total power demand is summarized and calculated.From 2015 to 2050,total electricity demand will continue to increase until it reaches 10665 TWh in 2050.Taking into account the impact of blast furnace slag and fly ash on the adjustment of the product structure in the cement industry,the impact of technology promotion and structural adjustment on power emission factors in the power industry,and the impact of the output ratio of electric furnace steel on the blast furnace slag output in the iron and steel industry,four scenarios including BAU,OPS,LCT,and PAD are established to assess the overall energy-saving and emission reduction potential of the steel-cement-power polygeneration system from 2015 to 2050.The results show that product structure adjustment and industrial symbiosis have a significant impact on energy conservation and emission reduction in key industries.By 2050,the total energy consumption and carbon emissions of polygeneration systems will reach 38697.64 PJ and 3767.73Mt CO₂.Product structure adjustment will lead to an increase in indirect carbon dioxide emissions,and the promotion of advanced technologies can avoid it.Based on scenario analysis,the indirect emissions from various industries,the production and use of solid waste in the polygeneration system,and the economic benefits they bring are discussed.Under the PAD scenario,by 2050,the proportion of fly ash used as a cement raw material will increase to 41%,and blast furnace slag supply may be insufficient.By 2050,comprehensive utilization of solid waste can bring economic benefits of 238.319 billion yuan to the system.Moreover,when the prices of blast furnace slag and fly ash are different,economic benefits of the polygeneration system will be affected to varying degrees.When prices increase by 50%,100%,and 150%,the economic benefits by 2050 will be 226.657 billion yuan,214.995 billion yuan,and 203.333 billion yuan.