Effects of magnetized water on vapor condensation and growth of fine particles

In order to promote the vapor condensation and growth of fine particles in the flue gas of coal-fired power plants and improve removal efficiency,a method to enhance the effect of particle growth under low super-saturation with magnetized water was proposed.The surface tension of water before and after being magnetized and its influence on the contact angle of carbonaceous particles with a poor wettability were measured.The supersaturated environment was formed by contact between hot water and cool air sol.The growth characteristic of carbonaceous particles was investigated in growth tube under magnetized water and tap water.Based on the classical heterogeneous nucleation theory,the effects of magnetized water on the critical saturation and growth rate of carbonaceous particles in the transition stage were calculated.The experimental results indicated that the surface tension of water decreased by 4.5 mN/m after 30 min of cyclic magnetization at 800 mT and the contact angle with carbonaceous particles decreased by 3°,which implied the wettability of carbonaceous particles was improved.Compared with tap water,the geometric mean particle size of carbonaceous particles increased from 1.42 μm to more than 3 μm,with better growth effect,and the promotion effect was more obvious at a lower supersaturation level.The theoretical calculation results showed that when water was magnetized,the critical saturation for the heterogeneous condensation of carbonaceous particles with the same size decreases significantly,which is more conducive to promoting the heterogeneous condensation of particles with smaller size.Magnetized water can help to improve the growth rate of carbonaceous particles in the transition stage under low supersaturation.The growth rate of carbonaceous particles in the transition stage under magnetized water is always higher than that of tap water.When at a lower supersaturation level,the growth rate of carbonaceous particles in the transition stage was improved obviously by magnetized water,and the growth effect of large particles is better.Magnetized water coupled vapor phase transition technology will be beneficial to the condensation of carbonaceous fine particles and the improvement of dusting efficiency of flue gas indirectly.