Patent ID: 7754102
Filing Date: 2010-07-13
Classification: B01D,Y02C

Abstract:
1. A method for the reclaim of carbon dioxide and nitrogen from boiler flue gas, comprising the following steps of: Washing flue gas with water for dust removal and then making water-washed flue gas to contact with a sulfite solution for desulfurization; Reusing adsorption liquid after sulfide products are obtained; Separating desulfurized flue gas by cyclone and sending desulfurized flue gas by an induced draft fan to a carbon dioxide absorber, wherein part of the carbon dioxide is absorbed by a carbon dioxide adsorption liquid and exhaust gas, which is emitted from the top of the carbon dioxide absorber, is, after the contained water is separated out, used as the material gas for the production of nitrogen, the said carbon dioxide adsorption liquid includes, besides water, 20-60 wt % water solution of compound amines, 5-10 wt % polyoxinolum, 1-5 wt % antioxygen and 1-5 wt % corrosion inhibitor based on the total weight of the carbon dioxide adsorption liquid; Freeze drying a nitrogen stream separated from the top of the carbon dioxide absorber for dehydration; providing liquid rich in carbon dioxide to a carbon dioxide heat exchanger and then to a rich-lean liquid heat exchanger and, after the heat is reclaimed, to a carbon dioxide regenerator; providing the adsorption liquid rich in carbon dioxide into the carbon dioxide regenerator from the top, wherein part of the carbon dioxide is desorbed by stripping, and then providing carbon dioxide adsorbed liquid into a reboiler for further desorption of the carbon dioxide; Making liquid lean in carbon dioxide flow out of the carbon dioxide regenerator from the bottom via exchanging heats in the rich and/or lean liquid heat exchangers into a water cooler and, after being cooled down, providing the liquid lean in carbon dioxide into the carbon dioxide absorber; Separating the desorbed carbon dioxide coupled with water vapor, after heat exchange and cooling, for the removal of the water, to resolve carbon dioxide as a product with purity of over 98.0%; and providing condensate water separated from regenerated gas to the carbon dioxide regenerator.