Process for quenching and cleaning a fuel gas mixture

Claim 1

A process for both (i) quenching a fuel gas mixture including at least one gaseous hydrocarbonaceous foulant which is (a) highly viscous in the liquid state, (b) higher boiling than water at the operating pressure in the zone wherein quenching is effected, and (c) a mist-former upon rapid cooling of the mixture, and (ii) removing from the fuel gas mixture at least a portion of said hydrocarbonaceous foulant without substantial formation of mist thereof in the fuel gas mixture, said process comprising the steps of: (a) contacting a flow of the gas mixture with a liquid jet spray of large droplets of a coolant mixture comprising liquid water and viscous liquid hydrocarbon, the temperature of said large droplets at the beginning of said contacting step being sufficiently lower than the lowest temperature at which said hydrocarbonaceous foulant vaporizes at the operating pressure in the zone wherein said contacting step is effected so as to enable the liquefication of a substantial portion of said foulant, the water being present in said coolant mixture at said beginning in a sufficiently low amount such that a substantial portion of the water will vaporize during a continued contact of said gas mixture with said coolant mixture, said continued contact being for a period of time sufficient to effect transfer of the resulting water vapor into admixture with said fuel gas mixture with the remaining droplets being substantially free of water, and (b) maintaining the contact for said period of time such that a substantial portion of said hydrocarbon foulant is liquefied and collected on said remaining droplets, and (c) removing said remaining droplets having hydrocarbon foulant deposited thereon from the treated fuel gas mixture in a gravitational separation zone.