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CO<inf>2</inf>-enriched flue gas recycling for more effective CO<inf>2</inf> sequestration
Date Issued
01-01-2009
Author(s)
Seepana, Sivaji
Indian Institute of Technology, Madras
Abstract
In the present paper, a new design of oxy-coal gasification combined cycle power plant is proposed based on the Intermediate temperature Diluted Oxygen Carbon sequestration (INDOCS) concept. Unlike in conventional exhaust gas recycling, the synthesis gas from coal gasification (syngas) is burnt in the presence of a preheated oxidant consisting of a reduced concentration of oxygen and CO2-enriched recycled flue gas. The oxidant is constituted by mixing oxygen from an air separator unit with exhaust gases from the gas turbine from which steam is partially removed in a flue gas conditioner. The reduced oxygen concentration will lead to lower conversion of N2 to NOx while recycling of the CO2-enriched, preheated exhaust gas leads to a higher mass flow rate and lower volumetric flow rate of the gaseous mixture. Thus, a more compact gas turbine can be used to generate the same power. The resulting flue gas is also significantly richer in CO2 at the gas turbine exit enabling a more efficient sequestration of CO2.