Methods For Assessing The Energy-saving Efficiency Of Industrial Symbiosis In Shandong Xinfa Eco-industrial Park

At present, the total energy consumption of China ranks second in the world, and China has grown up to be a big country of energy imports whose utilization rate of energy is only about 33%, lower 10% than that of developed countries. Following the consumption of energy, air pollution from fossil fuel is becoming burdensome. It is extremely urgent to save energy resource and reduce the emission of pollution.Energy-saving and emission reduction (ESER) work in China is still in an initial stage, research of which mainly focuses on the aspects of policies and regulations, renewable resources and high energy consuming industries.Construction of eco-industrial park(EIP), especially the development of industrial symbiosis(IS) has made an outstanding contribution to ESER. Moreover, eco-industrial park(EIP) is an important and effective carrier of the implementation of China’s basic national policy of circular economy which takes high-efficive use of resources and recycling as the goal,"3R" as the principle, forming closed circulation of material and energy cascade are used as the features. Since 2000, the EIP presented a great development and made outstanding contributions to ESER. Energy consumption per unit of GDP decreased 19.1% saving 630 milion tce, reducing 1.46billion tons emissions of CO2.In EEP, industrial symbiosis(IS) is a good mode to implement ESER, which is an effective method to optimize industrial structure, easing the contradiction between environment and economy, creating a resource-saving and environment-friendly society.Some typical patterns of industrial symbiosis have been established in China EIPs,like symbiosis network of cane-sugar-alcohol-paper-cogeneration in Guangxi Guigang EIP and green industry chains of ammonium phosphate-sulfuric acid-cement, use of sea water and thermokalite-power in Luxi chemical engineering EIP. Numerous scholars made considerable research on IS which mainly focused on methods of construction, factors affecting stability, analysis of carbon emission-reduction and wastewater reduction, material and energy flows, environmental and economic values. However, studies quantifying the energy-saving efficiency of IS remain insufficient. And analysis of energy-saving intensity and emission of SO2, NOx and dust through IS is absent. Moreover, there is no indexes system to make a quantitative evaluation on energy-saving of IS for theoretical and actual guidance when constructing IS mode in EIP.This paper proposes an index system for quantitative evaluation of the ESER efficiency of IS. Three standards and 17 element layers are selected, and Energy-saving indexes, financial indexes and environmental indexes compose the standards layer. Energy-saving indexes include the amount of energy-saving through IS, the IS energy-saving index, the contribution rate of energy saved through IS, fractional energy savings, and cut rate of energy consumption per total output value. Financial indexes include the IS investment payback period, IS input-output ratio, net present value (NPV), and internal rate of return (IRR) of IS. Environmental indexes contain emission reduction and emission-reduction rate of carbon, sulfur dioxide, nitrogen oxides and dust.Founded in 1972 and located in the Chiping Economic Development Zone in Liaocheng City, Shandong Province, the XinFa Eco-Industrial Park (XF EIP) is a development at the base of a thermal electric power plant. The XF EIP has 13 key enterprises that comprise an IS system of thermoelectricity, alumina, electrolytic aluminum, aluminum processing, caustic soda, calcium carbide, carbon processing, PVC, monosodium glutamate, and so on. The XF EIP owns 208 enterprises containing the largest local thermal EP plant in China. Three large production bases are designated for aluminum processing, aluminum powder production, and prebaked anode production. The proposed methods were applied to a case study on XF EIP, and data of 2008 and 2011 in XF EIP was investigated. The paper analysed the avenue of IS to save energy and reduce emission and quantitative effect of ESER through IS.Three energy-saving channels using IS were found in the XF IP:i)utilizing the energy of high-temperature materials among industrial processes, ii) recovering waste heat and steam between different processes, and iii) saving energy by sharing infrastructures. By means of the above channels,0.46million tce was saved counting 12.42% of the total energy consumption in XF EBP. The results showed that the energy efficiency index of IS was 0.33 accounting for 34.60% of the comprehensive energy-saving index(0.94) in 2011 which presented construction of IS in EIP was an effective way to save energy and reduce emission.0.19 billion Yuan was invested in constructing IS modes and the average values of the IS input-output ratio was 406.20 RMB/tce,57.20% lower than the price of standard coal. Static investment payback period in the XF IP was 8.5 months, indicating that the XF IP began to earn profit 8.5 months after the construction of all IS modes. The NVP and IRR of each IS mode in the XF IP were greater than zero, with average values equal to 1789.96 MRMB and 140.96%, respectively. The computation result for each indicator revealed that IS could lead to the use of energy with high efficiency and lighten the financial burden of enterprises in the XF IP. Emission of decrement of CO2,SO2, NOx and dust was 0.73 million ton,7.67 thousand ton,7.26 thousand ton and 4.46 thousand ton, respectively whose cut rate was 5.28%,7.87%,28.57% and 57.81% respectively.Based on the contribution of IS to ESER in EIP and the experience of constructing IS modes in XF EIP, we offered proposals for ESER in EIP and constructing IS modes.