Effect Investigation of Composite Humidification Way on Wall Deposition of Water Droplets and Desulfurization Process in Semi-dry CFB-FGD Tower

The single humidification ways is adopted in CFB-FGD technology, but it is difficult to achieve high efficiency desulfurization process as well as decreasing wall deposition of water droplets effectively. A new composite humidification way is put forward in this paper. The characters of water droplets particle concentration and diameter distribution and desulfurization efficiency were tested by PDA and FTIR spectrometer separately in semi-dry CFB-FGD tower. The effect of composite humidification way on wall deposition of water droplets and desulfurization process was analyzed. The results show that: Compared with single in-tower humidification way, the wall deposition of water droplets can be reduced effectively under composite humidification way. The appropriate R_in/total (quality ratio of in-tower humidification water to total humidification water) is between 61% and 78%. In this range both decreasing wall deposition effectively and keeping high efficiency desulfurization reaction can be achieved. The area of main desulfurization reaction is more focused on lower position of the tower, desulfurization reaction rate decreases more rapidly along the tower, but the whole desulfurization efficiency is enhanced in appropriate range of R_in/total under composite humidification way.