Process and plant for removal of acidic gas constituents from synthesis gas containing metal carbonyls

A plant for removal of carbon dioxide and hydrogen sulfide from a crude synthesis gas containing CO2, H2S, water and metal carbonyls with methanol as a scrubbing medium, comprising the following constituents and assemblies in fluid connection with one another:

• a) a means for supplying the crude synthesis gas to an absorption apparatus,
• b) an absorption apparatus, means for supplying the crude synthesis gas, a cold methanol sub-stream and at least one further methanol sub-stream recycled from downstream process stages to the absorption apparatus, means for discharging a product gas stream depleted in acidic gas constituents, water and metal carbonyls and a methanol sub-stream laden with acidic gas constituents, water and metal carbonyls,
• c) one or more apparatuses for multi-stage regeneration of the laden methanol sub-stream by pressure reduction (flashing) and/or temperature elevation (hot regeneration), means for supplying the laden methanol sub-stream to the regeneration apparatuses, means for recycling at least one regenerated methanol sub-stream to the absorption apparatus, means for discharging one or more carbon dioxide-and/or hydrogen sulfide-containing gas streams from the regeneration apparatuses, means for discharging a methanol sub-stream containing water and metal sulfides and depleted in acidic gas constituents from the regeneration apparatuses,
• d) a methanol-water separating column, means for introducing the methanol sub-stream containing water and metal sulfides and depleted in acidic gas constituents into the methanol-water separating column, means for discharging and recycling a methanol-containing tops product to the absorption apparatus and/or to the regeneration apparatuses, means for discharging a water-containing bottoms product,
• further comprising a methanol-water separating column and means
• e) which allow addition of water directly into a feed conduit of the methanol sub-stream containing water and metal carbonyls and depleted in acidic gas constituents before the introduction thereof into the methanol-water separating column and which
• allow injection of demineralized water directly into the methanol-water separating column at at least one point.