GB817560A - Removal of hydrocarbons from sulphur dioxide gases - Google Patents

Abstract

Sulphur dioxide gas containing hydrocarbons is contacted with an activated carbon adsorbent to remove the hydrocarbons. The humidity of the gas should be adjusted to below 10 per cent, preferably 1-6 per cent before contact with the adsorbent either by drying, e.g. with Conc. H2SO4, or without water removal by scrubbing with H2O at 0-80 DEG C., preferably 36 DEG C., and heating to 36-150 DEG C., preferably below 100 DEG C. The dew-point of the gas should be 0-80 DEG C. and the adsorption carried out not in excess of 150 DEG C., preferably 36-150 DEG C. The adsorbent may be coconut shell, peach nut shell, wood, or cellulose char, which has been steam activated at 400 DEG C., as pellets in a fixed or fluidized bed. The adsorbent is regenerated by water leaching and not air drying at 150 DEG C., and may also be treated with super heated steam at 400 DEG C. In the example gases from the roasting of leach sulphide concentrates are passed through an electrostatic precipitator at 0-90 DEG C., scrubbed with water at 20-22 DEG C., and passed through a second electrostatic precipitator at above 90 DEG C., a coke filter and the activated carbon layer, before entry into a contact H2SO4 plant containing a preheater, catalyst chamber, cooler and H2SO4 absorber.