Design Of Rotary Bioreactor Used In Municipal Solid Waste Aerobic Composting

Aiming at the municipal solid waste (MSW) aerobic composting process, a rotary bioreactor is designed to meet the need of the compost in this thesis. The research and development of aerobic composting technology and equipment is introduced. Several kinds of controllable factors which effect the process of aerobic composting is anlysized, including temperature, organic composition content, moisture content, PH, C/N and oxygen supply.According to the need of progress of the municiple solid waste anerobic composting, the structure of the rotary bioreactor has designed, including the structure design of reactor cylinder, the layout of the board, the selection and design of the gear, the structure design of the roller ring. The structure stress intensity of the rotary bioreactor is anlysized by ANSYS software. The simulation result shows that the maximum stress of the cylinder is located in the contact position between the bottom of the cylinder with the supporting device. The result is meet the strength requirement.The contact theory of the supporting device is studied, and the contact stress is analyzed by ANSYS software. The result shows that the maximum stress appears at the contact area of roller ring and roller, and the shape is rectangular, which is consistent with the Hertz contact theory. The result is meet the strength requirement.The internal flow field of the reactor is simulated and analyzed by FLUENT software. The simulation results of different structure of the board models show that maximum axial velocity appears at the spiral board model, minimal axial velocity appears at75°and80°resistant materials board models. The simulation results of different rotational velocity show that with the increasing of rotational velocity, the mixing extent between material and air increases. The simulation results of different material filling rate show that the axial pushing effect and the mixing effect of the material are the best when the filling rate is15%.After the completion of the installation and commissioning of the reactor, a series of preliminary experiments are carried on. The rotary bioreactor is used to compost MSW、MSW and dewatered sludge、MSW and waste paper. The effect of composting under different composting time is compared. The test results show that the reduction effect of all kinds of test materials is the best when composting time is2days, and the product of MSW is suitable for a raw material of the subsequent anaerobic digestion.The preliminary development of rotary bioreactor has achieved. The result will improve the efficiency of the MSW composting, and will guide the further structural optimization of the reactor in the future.