Design And Optimization Of The Equipment For Kitchen Waste Pretreatment

With the improvement of people’s living standards, the amount of municipal solid waste (MSW) in China is ever increasing, so the reasonable disposal of MSW is of significant importance. Due to the advantage of clean energy recovery, anaerobic digestion (AD) has been focused on and applied widely world-over as organic waste disposal. However, the complex component of kitchen waste in China which is influenced by citizens easily leads to the deterioration of the AD system. For solving the bottleneck of kitchen waste bio-energy utilization technology, efficient kitchen waste pretreatment equipment used for crushing and removing residuals is designed and R&D to achieve efficient separation of biomass, plastic and heavy components to enhance AD system efficiency and plastic recycling utilization. The main results of this thesis are as follows:(1) The analysis of kitchen waste physical and chemical properties in Hangzhou indicated that, the corrodible organic component of kitchen waste accounts for 68.36% on average, VS/TS averaged 71.43%, C/N averaged 15, therefore, the recycling potential is of a great promise. Because of high impurity rate (>30%), Including plastics, textiles, woods, glasses, ceramics, it posed a greater challenge on the application of anaerobic digestion.(2) Based on the efficient biomass crushing and fraetional sorting, two novel equipment for kitchen waste pretreatment with different physical properties was developed, and the theoretical calculation was performed. With the comparative analysis and evaluation, the concept design of vertical pretreatment equipment was selected. Based on the concept design of vertical pretreatment equipment, the size parameters and functional parameters in each functional zone were systematically calculated. The overall size of equipment was 1.6 m×1.6 m×3.5 m, and the theoretical power consumption was 41.91 kW. In addition, the theoretical capacity was 5 t/h, and the specific energy consumption of equipment was 8.4 kW·h/t-kitchen waste.(3) Using Solidworks software and designing the transmission system, the virtual prototype of pretreatment equipment was conducted and optimized. For the next step, the separate parts were assembled. For the independent functional zone as design unit, the virtual prototype was conducted, and the 3D design with finite element analysis was optimized. Based on the virtual prototype, the material of components was confirmed, and the pretreatment prototype was processed and assembled. An on-line debugging experiment with simulated waste was employed. Though the experiment analysis, the optimal values of conveying mechanism speed was confirmed. Correspondingly, the removal efficiency of heavy material and the purification efficiency of biomass were higher than 91% and 99%, respectively. The equipment for kitchen waste pretreatment basically meets the design requirements.