Patent EA-005015-B1 (EA)
Title: System for wet and dry removal of pollutants from gas and process therefor
Inventor: PAHLMAN JOHN E
IPC: C01G45/02
Filed: 2001-09-13
Abstract: 1. A system for combined wet and dry removal of target pollutants from gases comprising: a wet scrubber supplied with an acidic aqueous slurry of a sorbent of regenerable oxides of manganese being in particle form having an average particle size of less than about 0.1 to about 500 microns and a BET value ranging from about 1 to about 1000 m<2>/g, the wet scrubber being configured for introduction of a gas containing at least first and second target pollutant and to allow the gas be vented from the wet scrubber; a dry scrubber comprised of at least one reaction zone, a feeder configured to deliver a sorbent to the reaction zone, and a controller for regulating system operational parameters of the subsystem, the feeder containing a supply of a dry sorbent in particle form, the reaction zone being at least one bag house having fabric filter bags disposed therein, the bag house being connected to the reaction zone and configured to receive sorbent from the feeder and gas vented from the wet scrubber containing at least second target pollutant, the sorbent being regenerable oxides of manganese and/or regenerated oxides of manganese, which, upon regeneration, are in particle form and are defined by the chemical formula MnOX, where X is about 1.5 to 2.0 and wherein the oxides of manganese have a particle size of about 0.1 to about 500 microns and a BET value ranging from about 1 to about 1000 m<2> /g; a controller individually or simultaneously monitors and adjusts subsystem operational parameters and provides integrated control of subsystem differential pressure, target pollutant capture rates, gas inlet temperature into the reaction zone, sorbent feed rate, wherein the controller monitors and adjusts subsystem operational parameters relative to preset set points for each operational parameter and regulates differential pressure within the subsystems that any differential pressure across the subsystem is no greater than a pre-set differential set point and regulates target pollutant removal so that the target pollutants are removed at a rate not less than a pre-set target pollutant capture rate set point. 2. The system as claimed in Claim 1 wherein the system is comprised of two reaction zones, the two reaction zones being a first reaction zone and a second reaction zone. 3. The system as claimed in Claim 2 wherein the first reaction zone is a dry scrubber selected from the group consisting of a fluidized bed, a pseudo-fluidized bed, a reaction column, a fixed bed, a pipe/duct reactor, a moving bed, a bag house, an inverted bag house, bag house reactor, serpentine reactor, and a cyclone/multiclone and the second reaction zone is a wet scrubber. 4. The system as claimed in Claim 2 wherein the first reaction zone is a wet scrubber and the second reaction zone is a dry scrubber selected from the group consisting of a fluidized bed, a pseudo-fluidized bed, a reaction column, a fixed bed, a pipe/duct reactor, a moving bed, a bag house, an inverted bag house, bag house reactor, serpentine reactor, and a cyclone/multiclone. 5. A process for the removal of target pollutants from a gas stream with a system incorporating wet removal comprising the steps of: providing a system according to Claim 1; introducing a gas containing at least two target pollutants into a wet scrubber; contacting the gas in the we scrubber with the oxides of manganese in the sorbent slurry to capture the target pollutant through the formation of a reaction product of the first target pollutant and oxides of manganese to substantially strip the gas of the first target pollutant; and venting the gas from the reaction zone; introducing the gas vented from the wet scrubber into the bag house having fabric filter bags disposed therein, the gas containing at least the second target pollutant; contacting the gas in the bag house having fabric filter bags disposed therein with the sorbent for effective capturing of at least the second target pollutant through the formation of a reaction product of the second target pollutant and sorbent to substantially strip the gas of the second target pollutant; and venting the gas from the bag house of the systems at least the second target pollutant.