Patent ID: 8220247

Claim:
A process for controlling carbon dioxide exhaust from combustion of a gaseous fuel, comprising: (a) performing a power generation process, comprising (i) performing a combustion step by combusting a mixture comprising a gaseous fuel and an oxygen-containing gas, thereby generating a combustor exhaust stream comprising carbon dioxide and nitrogen, and (ii) routing the combustor exhaust stream as at least a portion of a working gas stream to a gas turbine, thereby generating electrical power and creating a turbine exhaust stream; (b) routing a first portion of the turbine exhaust stream back to the power generation process as a recycle gas stream; (c) withdrawing a second portion of the turbine exhaust stream as a partially concentrated carbon dioxide product stream; (d) routing a third portion of the turbine exhaust stream to a sweep-based membrane separation step, wherein the sweep-based membrane separation step comprises (i) providing a membrane having a feed side and a permeate side, and being selectively permeable to carbon dioxide over nitrogen and to carbon dioxide over oxygen, (ii) passing a feed gas comprising the third portion of the turbine exhaust stream across the feed side, (iii) passing air, oxygen-enriched air, or oxygen as a sweep stream across the permeate side, (iv) withdrawing from the feed side a carbon dioxide-depleted stream, (v) withdrawing from the permeate side a permeate stream comprising oxygen and carbon dioxide; and (e) passing the permeate stream back to the power generation process.