Treatment of Trace Chlorine Diffusing from a Hypochlorite Deodorization Process

Abstract

Treatment of trace chlorine in the exhaust gas from a hypochlorite deodorization process was investigated with sodium thiosulfate aqueous solution. The optimum conditions for treating 10 ppm of chlorine at normal temperature were clarified as follows; gas flow rate: 35 kg/h (superficial gas velocity: 1.5 m/s), liquid flow rate: 54 kg/h (liquid/gas ratio: 2l/m³), pH value of the absorption solution: 8-9, sodium thiosulfate concentration in the absorption solution: 500 ppm (w/v, molor ratio of Na₂S₂O₃/Cl₂: around 15). Under these conditions chlorine (0.1-0.2 ppm) in the exhaust gas was proved to be treated completely.