Patent ID: 8128898

Claim:
A process for at least partially removing hydrogen cyanide from synthesis gas to be used for Fischer-Tropsch synthesis and which includes carbon dioxide, the process including: feeding a synthesis gas containing hydrogen cyanide to a gas-liquid contacting stage; in the gas-liquid contacting stage, contacting the synthesis gas with an aqueous washing solution comprising at least one dissolved metal salt, with metal cations of the metal salt being capable of forming metal cyanide complexes and/or metal cyanide precipitates, and weak organic acid anions of the metal salt serving to buffer the pH of the washing solution in a range between 6 and 10, the washing solution including metal salts in a concentration in a range of 1 to 20 mass %, with hydrogen cyanide being washed from the synthesis gas by the washing solution to form a treated synthesis gas and a spent washing solution; withdrawing, from time to time or continuously, at least a portion of the spent washing solution from the gas-liquid contacting stage; and withdrawing the treated synthesis gas from the gas-liquid contacting stage.