Removal of Butyl Oxitol from Metal Coating Factory by Wet Scrubber

Abstract

The ethyl glycol monobutyl ether (butyl oxitol, BO), a volatile organic compound, is a toxic andwater soluble substance. The removal of this pollutant by using a wet scrubber is an interesting techniquedue to its low operation cost and pressure drop. The aims of this study were to investigate the absorptionefficiency of the wet scrubber and to determine the optimum operating conditions, which cause minimumeffect to production line. The effect of solution flow rate and dissolved BO concentration on absorptionefficiency was conducted in a pilot plant wet scrubber at the site. It was found that the absorption efficiencyof all water flow rates achieved 100% at the beginning of operation. Then, they gradually decreased andreached the minimum at 60%, 60% and 30% for water flow rate of 24.7, 19.7, and 14.6 m3/h, respectively.A wet scrubber system with water recycle at laboratory scale was conducted to study the effect of BO vaporflow rate at various water temperatures and loading ratios on the solubility of BO. It was indicated that theabsorption capacity of BO increased with increasing vapor flow rate and loading ratio but decreasing withincreasing of water temperature. Moreover, the absorption efficiency significantly declined when dissolvedBO concentration reached 12,000 ppm. BO absorption rate in gas and liquid phase were 1.89x10-5 kg/m3(column volume).s and 1.92x10-5 kg/m3 (water volume).s respectively. The simulation result showed thatthe wet scrubber was subject to loading ratio of 2.5 l/m3. The water should be changed on the third day ofoperation.

Keywords : Absorption / Metal coating / VOC removal / Wet scrubber / Butyl oxitol