Carbon dioxide recovery method and carbon- dioxide-recovery-type steam power generation system

Abstract

A carbon-dioxide-recovery-type steam power generation system comprises a boiler that generates steam through the combustion of fuel and generates an exhaust gas, an absorption tower that is supplied with the exhaust gas from the boiler, and allows carbon dioxide contained in the exhaust gas to be absorbed in an absorption liquid, a regeneration tower that is supplied with the absorption liquid having absorbed carbon dioxide from the absorption tower, discharges a carbon dioxide gas from the absorption liquid, and discharges the carbon dioxide gas, a reboiler that heats the absorption liquid discharged from the regeneration tower and supplies generated steam to the regeneration tower, a turbine that is supplied with steam from the boiler and is rotationally driven, a condenser that generates condensate by cooling steam exhausted from the turbine, a condensate pump that sends the condensate to a line, a water supply pump that is provided on the line and supplies water to the boiler, a compressor that compresses the carbon dioxide gas, and a cooler that is supplied with a part of the condensate and cools the carbon dioxide gas, which has been compressed by the compressor, while using the condensate as cooling water. The reboiler is supplied with steam that is exhausted from the turbine and steam that is generated by the cooling of the carbon dioxide gas at the cooler.

Description

technical field [0001] The invention relates to a carbon dioxide recovery method and a carbon dioxide recovery thermal power generation system. Background technique [0002] In power generation systems such as thermal power plants using a large amount of fossil fuels, an amine absorption method is used as a method of removing and recovering carbon dioxide, which is one of the causes of global warming (for example, refer to Patent Document 1). However, in the amine absorption method, a large amount of heat energy generated by low-pressure (for example, about 0.3 MPa) steam is required to regenerate the absorption liquid that has absorbed carbon dioxide. [0003] In order to compensate for this heat energy, the following method is proposed: the condensed water diverted from the turbine condensed water system, the heat carried by the recovered carbon dioxide, and the heat generated by compressing the carbon dioxide into the ground at high pressure (for example, about 8 MPa) Th...

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Problems solved by technology

[0004] However, in order to recover all the heat of carbon dioxide, there is a problem that the amount of condensed water is insufficient

Furthermore, as a result, there are problems in that the amount of condensed water flowing in the low-pressure heater is reduced, the amount of suction from the turbine is reduced and the heat transferred to the condenser is increased, and in order to reduce the effect of the conventional regeneration cycle, the output of the turbine is reduced relative to the recovered heat and not so much increase

[0005] Furthermore, when the recovered carbon dioxide is pressed into the ground, it is necessary to compress the carbon dioxide at a high pressure, but in order to secure such a compression power source, a huge output reduction of the power plant cannot be avoided

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