| Industrial parks,concentration area of industrial enterprises,have been the most active and potential economic growth point of China over the past thirty years,and has made an immense contribution to the national economic development.Due to the high concentration of industrial enterprises,industrial parks are severely restricted by resources,environment and other factors.Energy consumption intensity of resources and the high intensity of emission intensity caused the industrial park to enter the bottleneck.In order to alleviate the contradiction between economic output and environmental pollution of industrial parks,the concept of eco-industrial park emerged.Eco-industrial park is part of the implementation of circular economy strategy in China.By the end of 2016,there are 48 parks in China that have been officially approved as the national eco-industrial demonstration zone,and another 45 parks have been approved for the construction of the national eco-industrial demonstration zone.In the construction practice of more than ten years,the eco-industrial parks have achieved remarkable results in economic development,material decrement and circulation,and pollution control,but also exposed the problems of insufficient management of the parks.Industrial metabolic efficiency and industrial symbiosis structure of the industrial park are the main factors affecting the construction effect of ecological industrial parks.Through summarizing the research processes of industrial metabolic and industrial symbiosis structure of eco-industrial parks,and filed research of typical eco-industrial parks,we find that the research on industrial metabolic of small scale was still lacking,and the research on the evolution mechanism of industrial symbiosis network in the parks was not deep enough.Therefore,the objective of this article is to explore the relationship between industrial symbiosis network structure and material metabolic efficiency,to identify the operation state,to improve the operation effects of industrial parks,then to guide the symbiotic development of industrial parks from the perspective of process control.Specific research contents and conclusions are as follows:(1)By establishing the element flow analysis model at the small scale level of the parks,the industrial metabolism level of the core elements of the parks was dynamically analyzed and evaluated,the key links and influencing factors that limit the metabolic efficiency of the park were identified.The case study of the chlor-alkali industrial chain of Xinfa showed that the utilization efficiency of chlorine element in this industry chain has reached a high level,and the production process also has less impact on the environment from the perspective of elemental metabolism.Chlorine was discharged mainly in the form of chloride ions in wastewater,including brine transport,waste hydrochloric acid,waste alkali liquor,stripping wastewater,centrifugal mother liquid and other links.From the perspective of resource output,the development trend of chlorine-alkali industry is gradually changing from increasing the efficiency of material utilization and reducing pollutant emission to the product deep processing,which could obtain the higher resource yield of the industrial chain system.The case study of Xiangguang ecological industrial park showed that The metabolism efficiency of copper element and the metabolism efficiency of chlorine were both in a higher level,the reason was that the stable operation of the beneficiation unit in the park made the copper scrap could be recycled and reused,which caused the copper can be recycled inside the park.In Xingguang park,the copper elements were mainly lost in the form of slag,and the sulfur elements were lost by exhaust emission.Therefore,there were two ways to improve the level of copper element and sulfur element metabolism.The first way was technological innovation,through improving copper technology to reduce the copper content of smelting slag,and through improving acid technology to raise the rate of sulfur dioxide capture.The second way was the extension of industrial chains,the forward extension could guarantee the supply of raw materials,the rearward extension could improve the level of deep processing,and build a recycling network for waste copper recycling.(2)The topology model of industrial symbiosis network based on specific materials,energy carriers or key processes was established to analyze the structural characteristics of industrial symbiosis networks of eco-industrial parks from the point of the node and the network as a whole.At the same time,the key nodes of the industrial symbiosis network were identified and the vulnerability of the industrial symbiosis network is evaluated.This chapter took the Xinfa eco-industrial park as a case study.First,the core nodes in the industrial symbiosis network and the key nodes that may restrict the future development of the park were identified from the perspective of the degree centrality,betweenness centrality,closeness centrality and coreness.Second,according to the degree centrality and betweenness centrality,electrolytic aluminum,aluminum oxide powder and cogeneration were the most influential and dominant nodes in the industrial symbiosis network.At the same time,wastewater,bauxite and red mud also showed higher betweenness centrality.According to the closeness centrality,wastewater,electricity,fresh water showed relatively higher closeness centrality,which indicated that the industrial structure of Xinfa eco-industrial park is highly dependent on water and energy.Then,cohesion and centrality of industrial symbiosis network structure were evaluated from the overall perspective of the network,and the concept of symbiotic circle was put forward.Compared with 2006,the network density and clustering coefficient reduced,the network average distance is larger,and the symbiotic network shows a higher elasticity.The cohesive subgroups contained in the symbiosis network changed from two symbiotic circles including alumina powder and electrolytic aluminum to three symbiotic circles including alumina powder,electrolytic aluminum and liquid caustic soda.Upgrading of the industrial symbiosis network made the chlor-alkali industry become the core business of Xinfa industrial symbiosis network.(3)The influence mechanism of industrial symbiosis on the material,energy and water metabolism of the parks has been analyzed,and the concepts of eco-node and eco-edge have been put forward.Symbiosis network structure variation and operational effects of Xinfa eco-industrial park from 2006 to 2015 have been evaluated,by which the link between the industrial symbiosis network structure and the efficiency of material metabolism,and the feedback mechanism has been further discussed.The new industrial symbiosis network node will directly or indirectly affect the industrial metabolism efficiency.For example,the addition of venous node will greatly improve the comprehensive utilization rate of industrial solid waste in the park,the addition of intermediate product nodes will improve the efficiency of energy utilization and reduce the comprehensive energy intensity of the park,the addition of infrastructure nodes will improve the efficiency of water resources utilization and reduce the fresh water consumption intensity of the park.Take Xinfa industrial park as an example,by dynamic analysis of the energy consumption,water consumption and waste discharge from 2006 to 2015,the results showed that the waste nodes were translated into eco-nodes because of the addition of new nodes and formation of some industrial symbiosis relationships.The results also indicated the utilization efficiency of resources,energy and water in the park had been considerably improved.(4)At last,the management and control strategies based on process control were put forward aimed at the problems found in the research.Control strategies based on industrial metabolism perspective were to strengthen the construction of information statistics system,to set up the industrial metabolism analysis software system platform.The analysis results of industrial metabolism could assist to grasp the production and operation status of the park,and to find problems and inform relevant enterprises to take corresponding measures to preserve the stability of the park function.The control strategies based on industrial symbiosis network structure was to identify the problems by the construction of industrial symbiosis network model,to simulate the variation of industrial symbiosis networks,and to analyze the impact of new project introduction or original project exit on industrial symbiosis network,then to provide scientific support for management decisions. |
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