PROCESS AND APPARATUS FOR THE DRY REMOVAL OF POLLUTING MATERIAL FROM GAS STREAMS

A process for the removal of acidic gases from carrier gases employing a finely divided alkaline sorbent material is disclosed. The process includes, optionally, the step of conditioning the carrier gas to lower its temperature. The process comprises introducing a stream containing the alkaline sorbent material and mixing the alkaline sorbent material and the carrier gas, introducing a stream of vapor and liquid droplets and mixing the stream of vapor and liquid droplets with the stream of carrier gas containing the alkaline sorbent material. Thereafter a portion of the vapor is condensed and the alkaline sorbent material reacted with the acid gases to form products of reaction. Finally, the products of reaction and the remaining alkaline sorbent material are separated from the carrier gas stream. Preferably, the alkaline sorbent material is calcium based, e.g., calcium hydroxide or calcium carbonate and the vapor and liquid droplets comprise low pressure steam and water, respectively. The mixing process is facilitated by a free jet nozzle operated with a low pressure drop across the nozzle. The separation step may be formed in a fabric filter (baghouse) or an electrostatic precipitator.