Abstract: The present invention relates to a process for the manufacture of hydrogen sulfide by reacting sulfur and hydrogen which comprises two hydrogenation reactions. The first hydrogenation reaction of the present invention comprises the steps of supplying hydrogen gas in a reactor containing sulfur at least a part of which is in a liquid phase at a temperature of not lower than 250.degree. C., and reacting the liquid sulfur and the hydrogen gas to produce a crude hydrogen sulfide effluent gas in the reactor. The sulfur vapor contained in the effluent gas is further reacted with fleshly added hydrogen gas in the second hydrogenation reaction to further concentrate the resulting hydrogen sulfide.

Abstract: It has been believed that the Claus reaction in water without additive gives no more than very low conversion and some additive such as buffer or catalyst must be used to attain satisfactory H.sub.2 S conversion.However, it was discovered that when H.sub.2 S and SO.sub.2 are introduced in water simultaneously and continuously for hours, the conversion increased gradually and became steady at high level. The present invention was accomplished base on this inventive knowledge.