The Effect Of Particles Wetting On Dust Cake Uring The Process Of Gas-Solid Separation

Nowadays, the environment problem has become the focus of theworld because of the great negative influence of particles (especially PM2.5)pollution. Bag filters have assumed a commercially dominant role in dustremoval because of their excellent dust collection capabilities. The dustremoval arises as the dust-gas mixture passes through the filter media.Besides interception rate of particulates, pressure drop is also one ofimportant parameters evaluating bag filter performance. The increase ofpressure drop during filtration cycle is very significant because itdetermines the frequency of regeneration of the filter process andconsequently affects the lifetime of the filter bag. The porosity of dust cakedetermines the increasing rate of pressure drop, and the porosity of dustcake is closely relative with particle size distribution, particle inter-atomicforces, so increasing particle inter-atomic forces could lower pressure dropand reduce the regeneration frequency.Particle inter-atomic forces include van der Waals force, electrostaticforce and capillary force. In the environment of high humidity, capillaryforce increases to be the largest force because of the liquid bridge. Sowetting particulates in high humidity environment could increase particleinter-atomic forces so that improve the porosity of dust cake and reduce theregeneration frequency.The aim of this study is to give a better understanding of humidity effects on particle accumulation in bag filtration with a new hydrophobicPTFE membrane which has the high flux and the lower filtration resistance.Humidity is varied by inputting water vapor. The effect of humidity on thecapillary force between particles is considered, and the influence ofadhesion force on the particles accumulation behavior is alsoexperimentally investigated. In order to confirm the effect of adhesionforce on the cake formation, a special emphasis is given to the imageanalysis of the dust cake microscopic structure. As a theoretical guidance, asimulation method that accounts for the effects of adhesion force betweenparticles on the compression behavior of dust cakes composed ofmonodisperse particles will be developed in this study.