| High temperature incineration is currently recognized as an effective way to change the shape of medical waste,reduce its quality,completely kill pathogens,block the infection,and can be used as the preferred means of disposal of resources.In addition to setting up a suitable incinerator system,a quench device for dioxin controlling,an acid gas control device,a dust removal device and a final disposal of slag and dust remover are needed.For the formation of dioxins in the tail gas of high temperature incineration,the quench tower quickly reduce the exhaust gas temperature is currently main method of treatment,shorted the range of dioxin generating optimal retention time,and its generation can be controlled.The complicated flow field and temperature field in quench tower are the key factors for the stability of tower design and operation.It is difficult to describe the complicated flow field in a quench tower by simple laboratory tests.Therefore,it is a common method to simulate the system and optimize the process conditions by Computational fluid dynamics.In this paper,the numerical simulation and Optimization Study of gas-liquid two-phase flow in a quench tower of central waste incineration system of a medical waste harmless treatment center in Guangzhou was carried out by using FLUNET software.Pressure-Based solver k-ε equation model and Discrete Phase Model are selected to simulating the flue gas streaming and droplet evaporating in quench tower.The smoke flow and the droplet motion evaporation in the quench tower are simulated.The results showed that:smaller diameter of quench tower,higher of flue gas velocity,the collision of droplets and the tower wall cannot completely avoid,only as far as possible to reduce the collision probability and improve the inner wall temperature,to achieve stable operation of the quench tower;reasonable quench tower and nozzle protection structures can be achieved reasonable and stable "peak type" flow;liquid droplets is injected into high velocity region of flue gas which can reduce the probability of droplet impingement;through simulation experiments,the operation parameters and the working range of the quench tower and the nozzle ware obtained,the final choice is the FM10-20 type nozzle;the cooling water rate was 0.4-0.5kg/s,the export gas temperature range was 175-250 DEGC.Based on the simulation results,the quench tower of the medical waste incineration system in the harmless treatment center in Guangzhou was designed and constructed.The actual operation data matches very high with simulation data.its shows that the simulation results of FLUNET can guide the design of quench tower,and effectively short the equipment construction cycle. |
