Reducing foaming of alkaline wash liquids - for cracked hydrocarbon gases by adding heavy hydrocarbon oils

摘要

Foaming of thermally regenerable wash liquids, for removing CO2 and/or H2S from gases, is reduced by adding heavy hydrcarbon oils which contain unsatd., aromatic and/or polycyclic cpds. Esp. suitable are quench or heating oils from the thermal cracking of liq. hydrocarbons, heating oil from petroleum distn. or residual oil from the distillation separation of the products of hydrogenation of cracked benzene; if necessary, these oils are diluted with low-viscosity and-density hydrocarbons until their viscosities at 37.8 degrees C are 1.5 St or less and densities at 25 degrees C are 0.98g/cm3 or less. The antifoaming agent is added to the wash liq., before or as it is passed into the wash tower, to the extent of 0.05-3, pref. 0.1-0.5. vol. %. The antifoaming agent is removed, before or during regeneration of the wash liquid, by using a water-immiscible solvent; this may be a halogenated hydrocarbon or an aromatic-rich fraction from the thermal cracking of liq. hydrocarbons (in which case the oil-enriched soln. may be used for the cooling of cracked gas or mixed with heating oil and burned).