Gas/solid contact method for removing sulfur oxides from gases

Claim 1

A process for removing oxides of sulfur from a waste gas which comprises one or more oxides of sulfur and substantially all of the carbon is as carbon dioxide, said process comprising: a. continuously passing a stream of said waste gas into concurrent contact with fluidizable particles of a regenerable sulfur oxide adsorbent in a riser at a gas flow rate sufficiently high to assure fast fluid transport of said particles by said gas through said riser in a solely dilute phase entrained solids contacting zone for a period of time less than 30 seconds, at a superficial gas velocity of between 40 to 80 ft. per second and at a temperature between 250° F. to in excess of 1700° F., employing sufficient of said fluidizable particle to adsorb a desired amount of the oxides of sulfur in said gas, said adsorbent consisting essentially of particles having a particle size distribution suitabl for fluidization and being in the size range of about 20 to 150 microns with an average particle size in the range of 50 to 80 microns. b. immediately separatiing the gas from adsorbent particles now laden with oxides of sulfur at the outlet of said riser in a high efficiency separator to recover the majority of the adsorbent particles, whereby the adsorbent particles and gas containing oxides of sulfur are in contact with each other under conditions such that a bed of adsorbent particles is present, c. continuously passing the separated fluidizable particles of adsorbent into a regeneration zone, which is in flow communication with said adsorption zone, and containing said particles of adsorbent in said regeneration zone with a stream of reducing gas containing an effective amount of water vapor for a time and at a temperature sufficient to release substantially all adsorbed sulfur oxides and form a gas comprising hydrogen sulfide, d. continuously separating said gas comprising hydrogen sulfide from the hot fluidizable particles of absorbent now depleted of sulfur; and e. continuously circulating the fluidizable particles of adsorbent from step (d) to the riser in step (a) for contact with an incoding stream of gas containng one or more oxides of sulfur.