Comprehensive Evaluation Of Composting/Pyrolysis Of Municipal Organic Solid Waste Fermentation Biogas Residue

China’s economy has been growing steadily all year round and people’s living standards have been continuously improved.However,this has led to a significant increase in the output of municipal solid waste,resulting in serious environmental and social problems,affecting the natural environment and people’s normal life.Anaerobic fermentation is an efficient waste treatment technology,however,the biogas residue produced by it is the key problem to popularize this technology.The resource disposal of biogas residue is a technical direction in line with the national policy and economic development trend.In this context,based on the theoretical research of biogas residue pyrolysis and composting technology,this study will use the large-scale process simulation software Aspen Plus to simulate and analyze its process flow,and explore the change law of biogas residue thermochemistry and biochemistry;On this basis,the three environmental impact indicators of global warming potential（GWP）,acidification effect（AP）and eutrophication（EP）are quantitatively expressed by life cycle assessment method;Through data query,this paper makes economic analysis and evaluation on the investment,operation and product income of pyrolysis and composting technology,constructs an evaluation model with economy,environment and technology as indicators,and comprehensively evaluates the biogas residue disposal technology combined with fuzzy comprehensive evaluation and data envelopment analysis,so as to screen out a better biogas residue disposal technology scheme.The main conclusions are as follows:1.The biogas residue pyrolysis and composting model can be realized on Aspen Plus software.In the process of biogas residue pyrolysis,the simulated value of solid coke production is 47.21%,which is close to the literature data,and the model is effective.The output of solid product coke decreases gradually with the increase of temperature,and the downward trend slows down gradually.In addition,with the addition of CO₂atmosphere,the coke output also decreases gradually.In the process of biogas residue composting,the yield of organic fertilizer was 62.39%,which was close to the industrial results.However,due to the great influence of microorganisms in the process of aerobic composting,the change law of software simulation is not easy to realize.2.Among the environmental impacts caused by biogas residue pyrolysis and composting system,the potential value of global warming is the largest,which should be optimized first.GWP can be reduced by recycling CH₄in environmental emissions.For biogas residue pyrolysis technology,the environmental impact value of pyrolysis link accounts for the largest proportion,which is a key link that needs to be optimized and improved.It can be solved by optimizing the type selection of pyrolysis equipment,adopting energy-saving disposal mode and improving efficiency.In the biogas residue composting link,the environmental impact value of aerobic composting link accounts for a large proportion,which is mainly due to the degradation of biogas residue organic matter in this link,resulting in a large number of environmental emissions.3.Through economic analysis,the investment cost,operation cost and product income per ton of biogas residue in biogas residue pyrolysis technology are 86.76 yuan,221.4 yuan and 60.16 yuan respectively;Biogas residue composting technology is 17.00,434.53 yuan and 570 yuan respectively.Composting technology has greater economic advantages.4.The comprehensive evaluation results show that in terms of overall effectiveness,the overall pyrolysis efficiency value is 1,reaching the overall effectiveness;The composting technology is less than 1,which has the problems of excess input and insufficient output,or the existing scale is too large or too small.The technical efficiency of pyrolysis and composting is 1,which is technically effective,and the pyrolysis technology is also scaled effective;The scale efficiency of compost is less than 1,so it can be considered to expand the scale appropriately.