Pierced cylindrical gas inlet device for sulfur dioxide removal from waste gas streams

Configuration of a gas inlet device can significantly affect the performance of a tower for gas purification or separation. In this paper, a pierced cylindrical inlet device is investigated which consists of an evenly perforated wall and is tangentially located at the lower portion of a jet bubble reactor where an absorbent slurry exists. Incoming gas streams are evenly distributed into and flow through the absorbent slurry after leaving the inlet device, therefore, intensive agitation is resulted. Consequently, the gas, liquid, and solid phases mix completely, and the interfacial area for mass transfer within the tower increases dramatically. Results show that the tower achieved 95% SO2 removal and over 90% dust removal at a pressure drop of about 3 kPa for the entire tower, an incoming SO2 concentration of 0.12% (v/v) and a gas flux of about 2000 m3/h. When the depth of immersion of the grid holes increased from 0 mm to 100 mm, the pressure drop within the tower increased from 1.5 kPa to 3 kPa, and removal efficiency of SO2 increased from 50% to 95%. This gas inlet device overcame the problems of uneven distribution and short-circuiting of gas streams within a typical gas inlet device in a jet bubble reactor, and removal efficiency of SO2 by the tower was improved considerably. Clogging and scaling within the tower were also avoided. This type of gas inlet device is simple and effective for purification and treatment of waste gas streams.