Application Study Of Acoustic Agglomeration On Elimination Of Fine Particles

With the rapid development of economy,energy consumption is increasing year by year,while coal is in the main position of China's energy structure in the long term,so to control coal PM2.5 is urgent.Traditiona l dust removal equip ments are of low efficiency for PM2.5,so a large amount of fine particles discharge atmosphere.Agglomeration technology is to agglo merate fine particles first,then to remove larger partic les by traditional dust removal equipments.One of the potential and promis ing ways for PM2.5 remova l is acoustic agglomeration.Through both experiment and numerical simulation,this paper systematically studies the agglomeration effect of the fine particles.Orthokinetic agglomeration ? brownian agglo meration and turbulence agglo meration are chosen as coagulation mechanism in the acoustic agglo meration chamber.Based on the coupling of euler two-fluid model and population balance model,a relative ly perfect acoustic agglomeration calculation model is established.Numer ical simulation uses aerosol partic le number concentration measured in experiments of this paper as the initial conditions,and particle size distr ibution ranges from 0.3 to 2 microns.This paper established acoustic agglomeration experiment system,and the experiment system can verify the feasibility of using the established calculation model for numerical simulation analysis of the agglomeration effect of the fine particles and make experiments on the influence of acoustic frequency,sound intens ity,the angle between acoustic wave transfer direction and flow direction on agglo meration effect.The results showed that acoustic frequency exists an optimal value to achieve the best agglomeration effect,but in the range of experiment study,there is no optimum value of sound intensity,and the greater the sound intens ity is,the better the agglomeration effect is.The agglomeration effect of acoustic wave transfer direction paralle l to flow direction is better than the agglomeration effect of acoustic wave transfer direction vertical to flow direction.This paper puts forward a new type of acoustic agglomeration chamber,and this new type of acoustic agglomeration chamber add s turbulence device(cylinder,vortex sheet)to the traditional acoustic agglo meration chamber.Based on the discrete phase model,this paper has made numerical simulation research on flow field and particles movement in the new type of acoustic agglomeration chamber.The results found that vortex sheet can enhance sexual uneven distribution of flow field and extend the particle residence time,increasing the turbulent kinetic energy.In a word,vortex sheet is more suitable for the new type of acoustic agglomeration chamber.Based on acoustic agglomeration calculation model,this paper further optimizes the structure of the new type of acoustic agglomeration chamber,making numerical simulation research on the influence of the size,the column spacing,the line spacing,the shape and the arrange ment of vortex sheet and the particle volume fraction on agglomeration effect.Finally this paper obtained the best new type of acoustic agglomeration chamber.