PROCESS FOR THE REMOVAL OF NOX AND SOX FROM GAS STREAMS USING A WATER-SOLUBLE POLYMERIC CHELATE OF A POLYVALENT METAL AND MEMBRANE SEPARATION MEANS

摘要

The invention is a cyclic proces for removing NOx and SOx from a gas stream. The gas stream is scrubbed with an aqueous reaction solution containing an organic, water-soluble, polymeric chelate containing a polyvalent metal ion. The NOx is absorbed and in the presence of SOx, the imidodisulfonate is formed. The aqueous reaction solution containing chelate and imidodisulfonate is contacted with a first separation membrane, wherein calcium oxide is added to the first permeate stream, resulting in the precipitation of calcium sulfite. The calcium sulfite is filtered from the first permeate stream, the first permeate stream combined with the first non-permeate stream, and the combined stream contacted with a second separation membrane which removes a portion of the water and other low molecular weight materials. The remaining non-permeate stream containing chelate is recycled to the scrubber. Water-soluble alkali is added to the process as needed.