GB764401A - Improvements in or relating to methods of purifying chlorine - Google Patents

Abstract

<PICT:0764401/III/1> A gaseous mixture containing chlorine with inert atmospheric gases is introduced into an absorption zone at 30-210 lbs./sq. in. superatmospheric pressure, and contacted countercurrently therein with a carbon tetrachloride introduced at -9 to 90 DEG F. to form a solution of chlorine in carbon tetrachloride, which is withdrawn from the absorption zone at 50-95 DEG F. above the entering temperature of the carbon tetrachloride and substantially pure chlorine is recovered from the solution. A mixture of air with 30-50 per cent chlorine is compressed in 2 to 30-80 lbs./sq. in., may be cooled in optional cooler 4, and enters absorber 6 at 60-85 DEG F. Carbon tetrachloride at about 0 DEG F. enters absorber 6 at 7 and flows countercurrent to the gases dissolving chlorine. The solution is pumped from the base of the absorber through heat-exchanger 20 to a mid point of distillation column 12, in the lower portion of which stripping of the last traces of chlorine is effected by withdrawing some carbon tetrachloride through boiler 18 and returning it at 260 DEG F. to the column 12, while in the upper portion chlorine is separated from the carbon tetrachloride by fractionation. Chlorine is condensed in 14 and part is returned as reflux to column 12, while the remainder is withdrawn to produce. Carbon tetrachloride is pumped from column 12 through heat-exchanger 20 and water and brine coolers 22, 24 to absorber 6. In a modification in Fig. 2 (not shown) for treating air containing less than 20 per cent chlorine, solution is withdrawn from the base of the absorber and returned to a mid-point through a boiler. Other chlorine-containing gas mixtures from various methods of preparation are referred to as being suitable for treatment.