Research On Key Technologies Of Organic Solid Waste Composting System Based On Ventilation

The resource treatment of organic solid waste has become the focus of social attention.The composting treatment technology is simple,reliable,adaptable,flexible in process design,and low in secondary pollution.It can not only achieve harmless treatment of organic solid waste,but also realize resource utilization.It is one of the main methods of organic solid waste treatment.However,the traditional composting technology is extensive,the composting time is long,the process monitoring is simple,and the degree of intelligence is not high,resulting in unstable fertilizer efficiency,uneven quality,and low efficiency,which seriously hinders the development of composting technology and organic solid waste treatment industry.In order to develop the intelligent composting system,this thesis focuses on the key technologies such as ventilation influence,control and key structure.The main research work of the thesis includes:(1)Study on the amount of ventilation and its effects in the composting process.On the basis of experiments,the effects of ventilation on the parameters of temperature,pH value,total nitrogen,C/N ratio and seed germination index of composting process were studied,and the optimal ventilation capacity under experimental conditions was determined to be 2.5L/min.It can quickly enter the high temperature period and maintain a long high temperature time to achieve the complete harmless decomposing requirements.(2)Study on the influence of structural parameters of reactor air distribution device on air flow field.The internal air flow field of the compost reactor was simulated by Fluent software.The optimal opening ratio of the air distribution device was determined through the analysis of the flow field distribution of different cross sections.Based on this,the number of openings was further studied.The effect,ultimately resulting in a 9-hole arrangement at 9% open porosity,has the best airflow uniformity within the reactor stack.(3)Research on fuzzy PID control method for composting temperature.According to the complexity of the composting process,based on the regulation of ventilation,combined with the characteristics of classical PID and fuzzy control method,the fuzzy PID control algorithm of compost reactor temperature was studied and simulated.(4)Research on predictive model of compost maturity.In order to realize the prediction and control of composting process based on maturity,through the correlation analysis of theoretical analysis and experimental data,the auxiliary variables related to compost maturity were determined,and the prediction model of compost maturity was established based on multiple regression method.The prediction of the maturity prediction model shows that the predicted average error is about 10%.(5)Design of organic solid waste sequencing batch small composting system.On the basis of the above research,key structures and components such as compost reactor structure,air distribution device,tipping structure and monitoring system were designed to form a small-sequence batch composting system that can be monitored in real time.