It is usually regarded that industrial eco-systems perform quite well in economic benefits, social benefits and environmental benefits. Many successful cases of industrial eco-systems around the world have been reported in literatures. Social background, economic system, industrial categories and even geographical features may differ significantly among one another. Because of these differences, it seems very difficult to propose a universal framework to explain why some cases achieve more success and how the unsuccessful industrial systems can be transformed.
All the material/energy flows intra- and inter- any factories follow the same physical law and chemical law, providing the most promising and acceptable way to establish the method for understanding the process of eco-oriented transformation in industrial systems. Similar sectors and factories, with different organizing forms of production, may lead to different resource efficiencies and environmental benefits. The structure of industrial organization form plays a key role in connecting production activities at the micro level and the overall impact at the macro level. In recent years, the emergence of network theory shows great potentials in establishing a new method to uncover structural changes during transformation processes of industrial systems. The scientific question in this paper is how the structure of industrial systems changes within the process of ecology-oriented transformation.
From the common cognition in the research field of industrial ecology, industrial eco-system is abstracted and deconstructed into three types of networks: production network (PN), physical exchange network (PEN, by-products and product relations included), and industrial symbiosis network (ISN, utility sharing and physical exchange relations included). Based on the social network and complex network theory, a special analytical framework was suggested to uncover structural features of different networks. We collected 38 case studies published in SCI and CNKI databases and finally chose 13 cases with the guide of proposed principles of data filtering. In total, 15×3 industrial networks were reconstructed.
Subgraph was defined as the meso-structure of industrial networks. It was found that in most cases, the frequency of subgraphs with bidirectional subgraphs in PENs appeared much more often than in PNs. PENs preferred to form feed-forward subgraphs, quite different from the characteristics that subgraphs identified in natural eco-systems, but no structural preferences appeared in PNs or PENs. PNs showed obvious hierarchical features, while physical exchanges and utility sharing relationships tended to connect upstream and downstream production units and formed more complex structures. Meanwhile, these two types of symbiotic relationships formed some close-loop circulations of materials within production systems, which diversified the chains of material and energy transfer in ISNs.
• Complexity, resilience and sustainability , • Industrial symbiosis and eco-industrial development , • Network theory for industrial ecology
