Carbon Dioxide Emission Reduction Effect And Mechanism Of Industrial Symbiosis In Chinese Iron And Steel Industry

As one of typical energy-intensive, pollution-intensive and resource-based industries, the iron and steel industry in China has undergone long-term expansion with dispute. More recently, it faced huge dual pressures on energy saving and CO2 emission reduction from home and abroad, which attracted increasing researches on CO2 abatement measures. Among them, industrial symbiosis has been discovered to play a more and more significant role. Therefore, the dissertation aims to carry out a systematic study on the CO2 abatement effect of industrial symbiosis and mechanism of emission reduction for the iron and steel industry in China, at process, regional and national scales respectively. Four contributions have been made as follows: 1) Survey on ecologicalization history of the iron and steel industryNine typical industrial symbiotic systems in history were sorted out based on documentation methods, case investigation and expert interview. Ecologicalizaiton pathways were uncovered for core processes, auxiliary processes and symbiotic processes. The core processes constitute the foundation of the evolution of symbiotic systems. Technological progress and resource availability act as the long-term driving forces for the evolution. Only recently, the role of environmental factors emerged. This study provided a logic basis to quantitatively analyze the CO2 abatement effect of industrial symbiosis in the iron and steel industry. 2) Quantification of the CO2 abatement effect and contribution of industrial symbiosis in the iron and steel industryThe dissertation defined and identified three types of symbiotic measures, i.e. reuse and recycling of solid waste/byproducts, comprehensive utilization of gaseous waste/byproducts, and recovery and cascade use of sensible heat, screening 34 different measures. Methods for calculating the CO2 abatement contribution of symbiotic measures were proposed, and applied in a typical blast furnace- basic oxygen furnace(BF-BOF) route integrated steel mill. The results indicated that the mill emitted 2128.9 kg/ton of steel, representing the advanced level in China, and that total emission reduction from the symbiotic measures amounted to 1269.8 kg/ton of steel, with different levels of contribution from comprehensive utilization of gaseous waste/byproducts(68.4%), reuse and recycling of solid waste/byproducts(27.3%), and recovery and cascade use of sensible heat(4.3%). The abatement contribution from on-site symbiotic measures(64%) was higer than the abatement contribution from off-site symbiotic measures(36%). 3) Scenario analysis of CO2 emission of the iron and steel industry in Beijing-Tianjin-Hebei regionLong-range Energy Alternative Planning(LEAP) model was used to analyze CO2 emissions of the iron and steel industry in Beijing-Tianjin-Hebei region. Four scenarios were established, reference case, reduction case, marketing case and transition case. The results showed that the reduction case can lead to the minimum of CO2 emissions, due to the main driving force being scale of production, then followed by structure adjustment and. The least two influence factors were scale effect and technological improvement. 4) Econometric analysis of the carbon intensity of the iron and steel industry and the macroeconomic and policy factorsA conceptual model and an econometric model were put forward to examine the relationships between CO2 emission reduction, investment, technological expenditure of the iron and steel industry, and their connections with economic growth and policies in China from 1990 to 2010. The results indicated that technological expenditure can significantly reduce carbon emissions, and that CO2 emission reduction also played a significant role in enhancing the technological expenditure of the industry. Investment expansion showed a negative impact on CO2 emission reduction The impacts of policy on the development and CO2 emission reduction of the iron and steel industry showed different stages. The year 2000 was testified as a demarcation point. The command and control policies had a significant, positive effect on CO2 abatement, while the significant effect of incentive instruments was not verified.