Patent ID: 6159440
Filing Date: 2000-12-12
Classification: C01B

Abstract:
A process for continuous production of ammonium thiosulphate from a feed gas comprising H.sub.2 S, SO.sub.2 and NH.sub.3 comprising steps of producing in a first absorption step a solution of ammonium hydrogen sulphite by contacting a first gas stream comprising SO.sub.2 with NH.sub.3 and an aqueous solution comprising ammonium hydrogen sulphite in one or more absorbers connected in series and withdrawing a vent gas from one of the absorbers, passing the solution produced in the first absorption step to a second absorption step in which a second gas stream comprising H.sub.2 S is contacted with NH.sub.3 and an aqueous solution of ammonium thiosulphate thereby producing a solution being rich in ammonium thiosulphate and an off-gas,wherein the off-gas and the feed gas are incinerated and the incineration product is passed into the first absorption step.