The Vulnerability Mechanism Of Coal Industrial Symbiosis Networks Under Economic Fluctuations

The resource flow path of the traditional coal mining industrial system is “coal mining department? coal supply department? production department? transportation department? consumer group? natural environment.” This one-way linear resource flow has caused serious eco-environmental problems.The symbiosis network is constructed based on the resource management concept by designing an industrial symbiosis chain and recycling the waste,which will solve the problem of industrial pollution,improve efficiency of resource circulation and increase economic and ecological efficiency,and also attracts great interest of experts.Compared to conventional eco-industrial parks,the unique industrial connection properties and growth environment of coal industrial symbiosis network(CISN)require harsher stability conditions.The major industries of CISN are all the fundamental industries of the national economy.The statistical analysis on Morgan Stanley Capital International Index shows,compared with other industries,these industries are more sensitive to macroeconomic fluctuations.Thus,economic fluctuation play an important role in the healthy development of CISN.In the context of the depth adjustment of the global economy and wild fluctuations in energy prices,the vulnerability issue of the CISN has become a key restriction in sustainable development of coal mining areas.In recent years,many challenge-seeking scholars have spent considerable effort on CISN design,evolution mechanism,efficiency evaluation,and resource metabolism.However,the studies on the vulnerability of CISNs,especially the impact of economic fluctuations on their vulnerability,are limited.In this study,on the basis of sorting the literature and theory at present,we attempt an exploratory study on the vulnerability of CISN under economic fluctuations based on the research paradigm of “structure determines function”.First,we establish a vulnerability analytical framework for CISN under economic fluctuations and illustrate the conduction relationship of “economic fluctuations? transformation of business operations? structural changes of CISN? function degradation? performance decline.” Second,considering the direction of internal resources flow in CISN and the heterogeneity of the enterpris we propose an improved cascading failure model with a directed weighted network and design five network performance indicators(i.e.,relative value of cascading failure,relative value of maximal connected sub-graphs,average path length,network efficiency,and structure entropy)to measure the degree of damage on the whole CISN.Third,taking three coal eco-industrial parks in China as cases,through the simulation and comparative analysis on the improved model,we identify the impacts of energy price shocks and the falling demand on the vulnerability and of three types of CISN(i.e.,equality-based,dependent-based,and nested-based CISNs).The results indicate that the interaction between economic fluctuation and network structure is the key factor in determining system vulnerability.Concerning overall vulnerability,equality-based CISN is highest,dependent-based CISN is next,and nested-based CISN is lowest.Regarding disturbance type,the changes in the five performance indicators of the three types of CISN are more intense under energy price shocks than with declining demand.Moreover,the cascading failure scale of equalitybased CISN is greatest with declining demand,while the other two kinds of CISN's is greatest under energy price shocks.Concerning disturbance intensity,equality-based CISN shows initial value sensitivity to economic fluctuation,and nested-based CISN has the strongest tolerances for economic fluctuation.From the network performance perspective,the performance of nested-based CISN is superior to that of dependentbased and equality-based CISNs.Due to longer average path length and lower network efficiency,the failure diffusion trend of equality-based CISN shows the curve of TypeS,and the diffusion rate is smooth and slow.Contrariwise,the initial diffusion rate of dependent-based CISN is the highest,indicating that the loss of system efficiency can somewhat improve the system's anti-risk ability.The paper simulated and compared the impacts on CISN vulnerability of economic fluctuation by multi-agent modeling approach and obtained some results,which helps to widen or enrich the research perspective,content and method on the CISN vulnerability in theory,and the related research results provided a decision-making reference for the planning,design and stability governance of CISN in practice.