Evaluating The Metabolism Behavior Of Ferrous/Carbon Of An Iron And Steel Industrial Symbiosis Network

Industrial symbiosis is an important branch of industrial ecology,providing participants with environmental,economic and social benefits.The current research is mainly to assess the environment and economic benefits of industrial symbiosis.However,there are few studies concentrating on the metabolic behavior among participants of the industrial symbiosis network,especially lacking of the intra-firm level study.This paper takes the industrial symbiosis network of an iron and steel group in northwestern China as an example to study time-series metabolic behavior of involved compartments in terms of network utility,network control,network stability and information-based performance with ecological network analysis(ENA)by combining ferrous and carbon metabolism at intra-firm level.By setting up carbon emission reduction scenario analysis,the metabolic behavior of the iron and steel industrial symbiosis network in further realizing carbon emission reduction is evaluated,thus providing suggestions for optimizing iron metabolism and carbon metabolism.Main results are:(1)The number of direct fluxes of ferrous metabolism and carbon metabolism increases with the improvement of industrial symbiosis measures.Compared to ferrous metabolism,carbon metabolism always has more direct flow,and the link strength and connectivity of carbon metabolism are tighter than that of ferrous metabolism.It shows that the exchange of carbon resource is more intensive along the processes in the iron and steel industrial symbiosis network.(2)With the development of the industrial symbiosis network,the largest net producers of ferrous resource gradually change from dressing and ironmaking to sintering and ironmaking,and the net outputs of ironmaking gradually decreases which indicates that industrial symbiosis increases the supply capacity of ferrous resource of sintering and eases the pressure of ironmaking.The largest net consumers gradually change from the external environment and ironmaking to the externalenvironment and steelmaking.Thus,the production steelmaking is improved during the development of industrial symbiosis.In the carbon metabolism,coking and ironmaking are the biggest net producers,but the contribution of coking gradually decreases and then become smaller than that of ironmaking.The largest net consumers changes from the external environment and ironmaking to the external environment and coking.The increasing net input utilities of the external environment is reflected in the increase in production of pig iron and rolled steel.In addition,industrial symbiosis increases the capacity of ironmaking in supplying carbon resource and alleviates the pressure of coking in providing carbon resource.The increasing input net utility indicates that the external environment gains more carbon resource in the development of industrial symbiosis.The received net utility of waste management has gradually decreased,reflecting the advantages of industrial symbiosis in reducing waste emissions.Mutualism is the main pairwise type in ferrous metabolism,while exploitation is more prominent in carbon metabolism.The two substance metabolism both reach overall mutualism.(3)In the initial stage of industrial symbiosis network,the external environment has the highest control of ferrous metabolism and carbon metabolism for respectively54% and 58%,indicating that the production mainly depends on the materials and energy provided by the external environment.35% control on the ferrous metabolism is divided by steelmaking and rolling.But the external environment’s control degree over carbon resource transfers to the increasing control for iron-making,and steelmaking and rolling do not show major control over the carbon metabolism.The dependence of ferrous metabolism on the external environment gradually decrease during the development of industrial symbiosis.The control degrees of ironmaking and steelmaking are on the rise,but the distribution of the control over carbon metabolism has no obvious change,indicating that the implementation of industrial symbiosis affects the distribution of ferrous resource more.In general,the control degree of a process is proportional to the total throughflow of the process,but the change in control degree is more sensitive to the distribution of iron resources.(4)The hierarchical structure of the iron and steel industrial symbiosis network consists of six nutrient grades of the producer(the external environment),primary consumers(dressing,coking,sintering,pellet),secondary consumer(ironmaking),tertiary consumer(steelmaking),ultimate consumers(rolling)and decomposers(waste management).With the development of iron and steel industrial symbiosisnetwork,the structural composition of ferrous metabolism is relatively uniform.But the contribution of the external environment decreases while the contribution of dressing increased.The carbon metabolism structure gradually develops into a triangle,which meets the requirements of stable ecosystems.However,the carbon resource is mainly distributed at the bottom of the hierarchical structure,and the metabolism efficiency is relatively low.(5)Although the developmental capacity of ferrous metabolism and carbon metabolism is significantly positively correlated,carbon metabolism develops faster than ferrous metabolism.The growth of development capacity mainly depends on the expansion of the scale of the metabolic network,not the diversity.In the balance between efficiency and resistance,ferrous metabolism is dominated by efficiency,while carbon metabolism is dominated by resistance which explain that the utilization of ferrous resources is more efficient under the premise of emphasizing the production of steel products.(6)According to the scenario analysis,the scenario based on the fourth phase cannot achieve the emission reduction targets of 2020 and 2030.The promotion of new technologies can achieve substantial carbon emission reduction which only meets the carbon emission reduction target of 2020 but 2030.By adjusting energy structure,the emission reduction targets of 2030 can be achieved.Scrap-Electric furnace scenario does not show obvious emission reduction,mainly due to the low ratio of steel production.Only adjusting the energy structure or increasing the scrap-electric furnace separately cannot meet the emission reduction targets.As the ascendancy of ferrous metabolism in each emission reduction scenario increases significantly and exceeds that of carbon metabolism.Therefore,in realizing carbon emission reduction,the development of ferrous metabolism is required to be greatly improved,and the metabolic efficiency should be continuously improved.The ratio of ascendancy to development capacity in carbon metabolism is decreasing,reflecting that the increase of redundancy in carbon metabolism is faster,so the distribution of carbon resource among processes should be more uniform.