Study On Resource Utilization And Industrialization Of Kitchen Waste Based On Hydrothermal Method

In recent years,the production of domestic waste(including kitchen waste)in China has grown rapidly,and the corresponding treatment capacity does not match the growth rate,which makes it an increasingly important research topic to deal with domestic waste efficiently,especially kitchen waste with high moisture content and rich organic matter.In this paper,according to the characteristics of high water content and high organic matter content of kitchen waste,the rapid reduction and resource utilization of kitchen waste are carried out by hydrothermal method,and the pilot experiment is carried out to explore the feasibility of industrialization,which has important theoretical and practical significance.The main work of this paper is as follows : the experimental study of kitchen waste hydrothermal fertilizer,and the use of biological compost maturity evaluation method to analyze and evaluate the fertilizer effect of kitchen waste after hydrothermal treatment;the thermal energy and utilization of kitchen waste after hydrothermal carbon production were studied and explored.According to the characteristics of hydrothermal carbon utilization of kitchen waste,the calculation model of mass and energy balance was given.Process design and pilot equipment development of energy recycling equipment for kitchen waste ecological treatment;combined with the above research and analysis,a new model of on-site reduction and resource utilization of kitchen waste was proposed.Details are as follows :Combined with laboratory exploration and industrial test,the optimal reaction temperature for the hydrothermal synthesis of organic fertilizer from kitchen waste should be controlled at 170 – 180 °C,and the optimal reaction time should be 45 – 60 min.Except p H,all parameters of hydrothermal fertilizer for kitchen waste fully meet the relevant standards.The content of total nutrients,nitrogen,phosphorus and potassium reaches more than 6.4 %,and the content of organic components reaches more than 70 %,far exceeding the standard requirements.However,through the evaluation method of biocomposting maturity,the analysis and evaluation of the hydrothermal fertilizer effect of kitchen waste and the pot experiment verification,it was found that the hydrothermal fertilizers prepared under different reaction conditions were not completely mature,and the hydrothermal fertilizers prepared need to be reprocessed to be used safely.With the increase of hydrothermal reaction temperature,kitchen waste will be carbonized to form hydrothermal biochar.The most important factor affecting the thermal utilization of kitchen waste biochar is its free water content,and its bound water content has little effect on it.The calorific value of the hydrothermal carbon prepared after the hydrothermal reaction of kitchen waste also increased to a certain extent.Compared with the raw material,the hydrothermal biochar at 220 °C,250 °C and280 °C increased by 20.56 %,26.18 % and 35.22 %,respectively,and the calorific values were 21.99 MJ / kg,23.02 MJ / kg and 24.67 MJ / kg,respectively.Then according to the characteristics of kitchen waste hydrothermal carbonization,the calculation formula of mass and energy balance model is given,and the simulation calculation is carried out to draw the energy flow diagram of kitchen waste hydrothermal carbonization.Based on the feasibility of hydrothermal resource utilization of kitchen waste in laboratory,a complete set of ecological treatment equipment for kitchen waste was designed and developed for practical application and production.On the basis of large-scale treatment of kitchen waste,environmental impact analysis and thermal recycling were carried out to save energy and time to the maximum extent.Among them,the key technologies of ’ Gemini ’ reactor in pilot plant mainly include heat transfer oil energy cycle and hydrothermal steam energy cycle.Finally,based on the above experimental research and industrialization analysis,a new model of in-situ reduction and recycling of kitchen waste based on hydrothermal method is proposed,which provides a reference for the industrial development of kitchen waste hydrothermal treatment.There are 31 figures,18 tables and 112 references.