Study On Turbulent Agglomeration Of Coal-fired Fine Particles Under Vapor Phase Transition

The human living environment is being flooded with a lot of fine particles,which not only seriously affect the atmospheric environment but also endanger human health.Studies have shown that the main reason for the harm of fine particles is that they are small in size and large in number,and the existing dust removing equipment is difficult to remove.Therefore,using certain physical or chemical means to induce fine particles grow larger particles and remove by the conventional pretreatment technology has received more attention.Taking into account the current widespread use of coal-fired power plant wet,semi-dry flue gas treatment process,the flue gas has a greater relative humidity.Only adding a small amount of ste am can create the supersaturated environment required for heterogeneous nucleation of fine particles,which creates favorable conditions for the realization of vapor phase-change agglomeration technology.In addition,the turbulent agglomeration technique uses the vortex structure to guide the fine particles to aggregate with the vortex and agglomerate into agglomeration particles with a larger particle size.The utility model has the advantages of simple device structure and low operation cost,and also attracts extensive attention.In this paper,the corresponding modules of fine particle removal technology and fluid dynamics software are understood,and the advantages and disadvantages of various agglomeration techniques and simulation methods are compared.On the basis of summarizing the previous researches on the agglomeration technology of fine particles,further studies on the techniques of vapor phase-change agglomeration and turbulent agglomeration.The UDF was used to write a kernel function suitable for the vapor phase-change agglomeration technique,and the technique was coupled with the turbulent agglomeration technique.First of all,a vapor phase change reunion chamber was established,and the effect of the amount of steam and flue gas temperature on the agglomeration of fine particles was analyzed.The results show that the supersaturated environment is a necessary condition for heterogeneous nucleation.The more steam is added,the better the fine particle size increases.The greater the temperature difference between flue gas and steam,the higher the degree of supersaturation,the more significant the effect of particle size growth.Secondly,the agglomeration of fine particles and the effect of pressure drop in the agglomeration chamber under the two types of "one" and "C".The results show that the "C"-shaped scroll can produce a symmetric vortex structure compared to the "one" shaped scroll,and the number of outlet large particles is more dense and the "C"-shaped scroll can have a smaller Pressure drop level.The optimal arrangement of the "C"-shaped scroll was optimized and the best vortex spacing was selected.Finally,a new type of phase-change aggregation chamber is proposed based on vapor phase transition and turbulent agglomeration.The characteristics of the flow field and the agglomeration effect of the new phase change reunion chamber were analyzed,and the agglomeration effect was analyzed.It was confirmed that the new agglomeration chamber had good agglomeration effect.