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This paper deals with the application of emergy analysis of industrial systems in considering wastes. Making process system engineering decisions that are ecologically conscious requires emergy analysis of both industrial and ecological processes. The traditional emergy analysis methods of a natural ecological system usually do not consider the impact of wastes. This paper considers the impact of wastes and improves existing emergy analysis methods for industrial system. A new index of sustainability for industrial processes is presented. [Copyright &y& Elsevier]

Summary China is coal dependent, and this situation will persist for a long time. Because more and more attention has been paid to energy security, the coal-chemical industry has become a hot topic and has developed quickly. To improve efficiency and reduce emissions, industrial symbiosis (IS) can be introduced when establishing a coal-chemical eco-industrial system to achieve harmonious development between nature, industry, and society. In order to learn the influence of IS on the current industrial system, a model of coal-chemical eco-industrial systems was built. Using scenario optimization and linear programming, the behaviors and optimal industrial structures of the system under different scenario settings were compared, and industrial ecological analysis was performed. By comparative analysis, results showed that the greatest proportional decrease in the use of coal for coking was 15% compared with actual data for 2005. The resource-productivity and eco-productivity were 828 yuan/ton and 2.51, which are much higher than the values of 548 yuan/ton and 1.23 in 2005. The symbiosis index and the link density were found to be 0.675 and 1.67, compared with 0.588 and 0.94 in 2005. Research results showed that the coal-chemical eco-industrial system achieved a high value-added utilization of coal and an updated product profile. Such systems will constitute the main direction and the inevitable trend of China's coal utilization in the future, which will reduce the harm to the environment from increased coal use and benefit the energy industry, the economy, and society. [ABSTRACT FROM AUTHOR]

Abstract: China, an oil and NG scarcity country, is coal dependent, and this situation will remain for a long time. DME, as an ideal replacer of liquid fuel, is considered to develop. The efficient way of producing DME from coal is under research. Considering the components of coal and natural gas (NG), we choose co-feed (coal and NG) and co-production (electricity and DME) system (Co–Co system) to be studied on. Three systems which are the standalone system, co-generation system and Co–Co system are simulated by Aspen-Plus. The simulation results concerning material flows, exergy flows, CO2 emission and the evaluation indexes are obtained. It is found that Co–Co system has higher exergy efficiency, higher economic benefit, and it is environmental friendly because of releasing the least CO2.The analysis illustrates that Co–Co system has obviously advantage over the other two kinds of systems. [Copyright &y& Elsevier]

Modern human activities greatly disturb substance flows in nature and senselessly discard massive amounts of precious resources to natural waste reservoirs; phosphorus (P) is a good example of this. In this article, substance flow analysis is employed to quantify and explore the temporal evolution of China's P consumption in main metabolic nodes from 1984 to 2008, and then the environmental implications for P flows into both surface waters and natural soil are investigated. Results show that the metabolic nodes of human life and animal husbandry have demanded increasingly more P inputs, while disseminating more and more P wastes, with the waste recycling ratios of these processes dropping, respectively, from 65.9% and 66.1% in 1984 to 50.7% and 40.6% by 2008. These change traits were closely related to national polices including the Household Contract Responsibility System and the Shopping Basket Program, as well as the policy vacuum existing between China's agricultural and environmental administration departments. To achieve high crop yield, increasingly more inorganic P fertilizers have been utilized in China, but their use efficiency has decreased by 46.3%. From 2003 to 2008, the total P load into surface waters was stabilized at about 900.0 kilotons (kt), while the total P load into natural soil increased by more than 3.8 times to 3,131.3 kt P in 2008. City life and the intensive breeding of crops are identified as the main targets for further pollution control and nutrient recycling in China. Some suggestions for achieving environmentally sound practices and resource sustainability in China are proposed at the end of this article. [ABSTRACT FROM AUTHOR]

Abstract: Substance flow analysis was used to develop a stock and flow model that was applied to time-series data from 1984 to 2008 to explore the correlation between change traits of anthropogenic phosphorus (P) metabolism in China and socioeconomic variables, quantify the accumulation of P in natural reservoirs and search for man-made stocks with the greatest potential for recovering P resources. The results showed that a total of 154.5 Tg P was extracted in China, but 80.5% was lost to natural water and soil, indicating the unsustainability of societal P metabolism. Urbanization, improved standards of living and population growth are responsible for the rising magnitudes of the P flows related to ore extraction, use and waste generation and the declining ratio of recycled P wastes, while inefficient small mines and corresponding restrictive policies contributed to the large fluctuation in ore extraction and waste generation in 2001–2008. Financial and policy support, combined with technological advances, strongly promoted the progress of the phosphate fertilizer industry in China, which transformed the country from a net importer into a net exporter of P materials after 2000. Three anthropogenic stocks were formed: 38.3 Tg P in agricultural soil, 19.0 Tg P in natural water and 105.3 Tg in natural soil. The last stock included 41.4 Tg P in mining wastes abandoned by small mines, which will be valuable human-induced mines for the secondary recovery of P resources in the future. Model uncertainties are analyzed, and conclusions and suggestions are presented. [Copyright &y& Elsevier]

Abstract: It is important to analyze why phosphorus metabolism is unsustainable in China''s modern industrial society. In this paper, the Substance Flow Analysis (SFA) approach is used to build different models of phosphorus metabolism for the following three periods: the prehuman period, traditional agricultural period and modern industrial period. Based on these models, the evolution process of phosphorus metabolism in China is analyzed from the viewpoint of its metabolic structure and intensity. The indices of intensity analysis involve phosphorus input, phosphorus circulation and recycling efficiency, phosphorus production and production efficiency, water phosphorus emission and water emission proportion, solid waste phosphorus output and solid waste discharge proportion. Through the analysis of the evolution process, the key factors that cause the lack of sustainability of phosphorus metabolism in China are identified, which can be summarized by four aspects: the increase of soil phosphorus accumulation, the increase of water phosphorus emission, the decrease of recycling efficiency and the decrease of production efficiency in croplands. Furthermore, the specific unsustainable processes of phosphor resources utilization in China are discussed. For these unsustainable processes, the relevant solutions for the phosphor resources crisis are given. [Copyright &y& Elsevier]