Coal-Gas-Burned High Efficiency Power Plant which Recovers Carbon Dioxide Generated

Abstract

This paper describes a construction and a characteristics of a coal-gas-burned high efficiency power plant which emits no carbon dioxide (CO₂) into the atmosphere. In a plant, CO₂ gas and superheated steam are used as the main and the sub working fluid, respectively, of a closed dual fluid regenerative gas turbine power plant. Since coal gas composed of CO, H₂, CO₂ and CH₄ is burnt in a combustor using oxygen, the exhaust gas led into a condenser includs only CO₂ and H₂O. Hence, CO₂ gas can be easily separated at the condenser outlet from condensate. In the plant, the combustion gas is first used to generate power by driving a turbine. High-temperature turbine exhaust gas is next utilized at a regenerator to heat the main working fluid of CO₂ gas flowing into the combustor, and then is utilized at a waste heat boiler to produce the superheated steam injected into the combustor. It is estimated that the power can be generated with gross thermal efficiency of 54.4%, and that the power generating efficiency is 46.7% which is calculated by subtracting the power required for producing the high-pressure oxygen used for combustion from the generator output. It is shown that the estimated efficiency is higher by 18.1 percentage points than that of a conventional boiler steam turbine power generating plant into which a process for removing and recovering CO₂ from the stack gas by utilizing alkanolamine-based solvent is integrated.