The Analysis And Improvement Of The Ventilation System In Mixed Sludge Biochemical Treatment Process Of A Certain City

During the process of mud fermentation, the aeration gives off large amount of vapor, ammonia and other foul gases, which will result in paroxysmal diffused pollution. Meanwhile, fresh air should be sent to satisfy the microorganism reaction conditions in the process of mud fermentation, through the piled body, air turns into waste gas, containing large amount of vapor, ammonia and other foul gases, disperses in the workshop and causes constant diffused pollution. With insufficient control of polluted gases, gases in the workshop will diffuse outside of the workshop, which will definitely lead to air pollution and affect the whole fermentation process.Higher requirements of ventilation and dehumidification are put forward, former related designs lay more emphasis on the control of foul gases of the workshop, while dehumidification is relatively neglected, which causes dehumidification problems of workshops in the cold regions in winter and failure to meet the requirements of the certain degree of craftwork.In view of these problems discussed before, this paper chooses the polluted gas emission system of mud fermentation of the workshop as the study subject, which aims at designing air current organization reasonably in order to control diffuse distribution of polluted gases in the workshop, in the meantime, focuses on solutions of dehumidification in cold weather by means of local ventilation.First of all, analyze the polluted gas in the workshop through general ventilation in large buildings such as a mud plant; analyze the yearly thermal process and combines with craftwork to undertake related study of diffusion characteristic of pollutants given off from the surface of composter.Secondly, carry out the construction of CFD model and the study of simulation, in order to perfect the injecting ventilation scheme of the mud fermentation workshop. Conduct related numerical simulation of integral ventilation effect and local ventilation effect of axial compressor ventilation, and at the same time, bring forward the plan of installing guide vane on the basis of the original design from the perspective of airflow structure, which aims at optimizing ventilation effectiveness. By installing different angles of the guide vane on axial flow fans, according to the ventilation simulated effect, draw a conclusion of movement of polluted gases and analyze the reason of producing pollutants recalculating zone.Thirdly, according to the difficulty of dehumidification in cold weather, put forward a ventilation airflow control scheme of "single hose"+"drape" in attempt to solve the problem, which mainly includes high possibilities of condensation of moisture and even freeze in workshop in winter. Take advantage of local ventilation and by way of reducing heat exchange to lessen the negative effects of condensation of moisture and freeze on craftwork, conduct orthogonal numerical model tests and analyze the results of streamline, airflow velocity field of this control scheme. The results show that the airspeed is higher in the air duct, the average speed is15m/s, it helps drying rapidly.Last but not the least, combine the practical project to accomplish a ventilation and dehumidification design of mud workshop of a city, reconstruct the original system in order to optimize the dehumidification effect and airflow structure, and provide reference for future designs.