Removal of nickel tetra:carbonyl and iron penta:carbonyl from hydrogen sulphide gases - by washing with methanol and removing condensate

摘要

Removal of Ni(CO)4 and Fe(CO)5 from H2S-rich gases. esp. Claus gas produced during methanol washing of crude synthesis gas and regeneration of the loaded methanol, comprises subjecting the Claus gas, cooled in many stages, to postwashing with metal carbonyl-free methanol, adding the washing soln. to the methanol washings and completely or partially removing the condensate from the last cooling stage from the process. PREFERRED PROCESS - Pref. the Claus gas stream, cooled to at least 40 deg.C is cooled to -15 to -55 deg.C in the last stage. Postwashing takes place at -15 to -55 (pref. -25 to -45) deg.C at 100-400 kPa superpressure. Metal carbonyl-free cold methanol from washing of crude synethesis gas is used as the postwash methanol. Postwashing of the Claus gas occurs by fine distribution of the washing liq. in the gas stream. Postwashing is a one- or multistage process. The loaded postwashing methanol is fed into the liq. phase of the condensate from the cooling stages of the Claus gas. ADVANTAGE - The removal of metal carbonyl prevents disturbances in the Claus Proces