NOVELTY - Purifying gases comprises gasifying a fuel (1) to raw synthesis gas containing carbon monoxide and vapor in a gasification reactor (2) in the presence of a calcium compound and vapor, removing halogens (7), converting carbon monoxide and vapor, contacting shifted gas (9) with a sulfur sorbent, regenerating the sorbent and transferring hydrogen sulfide into the gasification reactor and removing purified shifted gas (10).    USE - The method is useful for purifying gases (claimed), in particular desulfurization of gases, which is useful for the production of e.g. ammonia and methanol.    ADVANTAGE - The method is simple for cleaning high thermal efficiency of gases from gasification units. The method reduces the sulfur.    DETAILED DESCRIPTION - Purifying gases from a gasification unit, comprises gasification of a fuel (1) to raw synthesis gas (3) containing carbon monoxide and vapor in a gasification reactor (2) in the presence of a calcium containing compound and vapor; removal of halogen compounds (7) from the raw synthesis gas, catalytic conversion of carbon monoxide and vapor in the raw synthesis gas to carbon dioxide and hydrogen in a water-gas-shift-conversion step (8), in order to obtain a converted gas, contacting the shifted gas (9) with a solid sulfur sorbent, regeneration of the sorbent for the solid sulfur by means of a vapor stream (12) through the solid sulfur sorbent against the direction of flow of the shifted gas to retain the vapor stream containing hydrogen sulfide, transferring the vapor stream containing hydrogen sulfide from the sorbent for the solid sulfur directly into the gasification reactor and removing the purified shifted gas (10) from the solid sulfur sorbent.    DESCRIPTION OF DRAWING(S) - The flow diagram illustrates the gas purification method:    Fuel; (1)    Gasification reactor; (2)    Synthesis gas; (3)    Fine ash; (5)    Halogen; (7)    Water-gas-shift-conversion step; (8)    Shifted gas; (9)    Purified gas; (10)    Sulfur absorption reactor; (10)    Vapor stream. (12)