GB847699A - Quenching and purification of gaseous reaction products - Google Patents

Abstract

<PICT:0847699/IV(b)/1> In a process where hydrocarbons are present at low partial pressures in the presence of steam and the gaseous effluent contains polymer and other emulsion-forming contaminants and is quenched to lower the temperature and remove such contaminants, the effluent is passed into the lower section of a quench zone having an upper and a lower section separated by means preventing entrained liquid passing from the lower to the upper section, contacting the effluent with quench oil in the lower section and water in the upper section and recovering cooled effluent free of emulsion-forming contaminants. The quenching process is particularly useful for the effluent from a butene dehydrogenation process forming butadiene. In such a process the effluent from reactor 2 may be at 925 DEG -1,250 DEG F. and 2-10 psig. It is cooled to 450 DEG -700 DEG F. and passed into the lower section B of quench zone 7 where it is scrubbed with oil from line 16. The oil may be saturated or unsaturated having an initial boiling point above the highest temperature in zone B. The oil is circulated from the bottom of the zone back to the top with cooling, contaminated oil being removed by line 21 and fresh oil being added by line 15. The oil is passed to the zone at a rate of 350,000-900,000 lbs./hr. and a temperature of 140 DEG -230 DEG F. The gas passes up to the upper Section A the two sections being separated by a screen 9 or a layer of Raschig rings or Berl saddles or merely a space. In the upper section the gas is washed with water from line 10 to 90 DEG -200 DEG F. fed at a water to feed weight ratio of 0,5-2 : 1. The water removed by line 11 passes to separator 12 where oil is allowed to separate out and is passed by line 14 to zone B. The water is obtained by condensation of steam from the gases.