Numerical Simulation And Optimization Of Ventilation For Cesspit In Waste Incineration Power Plant

Waste production is increasing year by year in our country, the main processing methods including landfill, composting and incineration. With the start and gradually development of waste incineration power generation technology, waste incineration becomes more and more widely used because of its various advantages. After entering the incineration power plant, the garbage can produce stench gas in each phase. Therefore, whether the stench gas in garbage cesspit will leak and affect the surrounding environment is gradually drawing attention.To solve the problem of garbage incineration power plant odor, various measures appear. The prevention measures of garbage cesspit odor including set vertical wind curtain in front of the waste discharge outlet, set automatic discharging door and set primary air fans extracting air from the garbage cesspit as incinerator combustion air in order to guarantee the negative pressure inside the cesspit, etc. For analysis and put forward the improvement scheme on this question, the flow field and pressure field of garbage cesspit was studied by the method of CFD numerical simulation under various conditions in this topic. Besides that, the design of the ventilation system under the condition of the accident is also considered.This paper discusses the typical and the adverse conditions by the method of CFD numerical simulation. Because of the difference of the fan open and discharging door open conditions, the pressure distribution, air flow, etc all can produce change, therefore, the pressure field and flow field should be studied through the numerical simulation. The simulation results show that in the case of don’t open the unloading door, negative pressure is too high inside the cesspit whether the fan is open or not. So the advice is to ensure open area of0.8m2; In the case of open a discharging door, when only to open a fan, air leakage will exist and may cause stench spillover; when to open in the last two fans, the micro-negative pressure can be formed. In the case of open two discharging door, only to open a primary air fan, will cause positive pressure at a few position and air leakage through part of the discharging door gap; When to pen two fans, although the cesspit is in a micro-negative pressure state, but the local position is in the critical state; When to open three fans, the negative pressure value is stable. According to the simulation results, the improved scheme of adding sew exhaustion is put forward. Simulation results show that the flow is more uniform, but the negative pressure value at the discharge outlet is still small, and can be greatly influenced by outside. Also leaks occur in adverse circumstances.In order to minimize the impact of odor to the environment around during the accident cases such as the furnace overhaul, this paper has carried on the design of emergency ventilation system. The air is extracted from the cesspit by the fan, and then transported through special air duct connecting to the liquid washing deodorant device to remove odor and pollution. After all these processes, the gas is expelled through the exhaust funnel.