Device and method for jointly capturing and recovering carbon dioxide and nitrogen in flue gas

Abstract

The invention provides a device and method for jointly capturing and recovering carbon dioxide and nitrogen in flue gas. The device comprises a flue gas treatment system, a first CO2 membrane separation unit, a second CO2 membrane separation unit and an N2 membrane separation unit, wherein the flue gas treatment system is provided with a treatment inlet and a treatment outlet, and is used for treating the flue gas; the first CO2 membrane separation unit is provided with a first gas inlet, a first carbon dioxide enriched gas outlet and a first high-pressure impermeable gas outlet, and the firstgas inlet is connected with the treatment outlet; the second CO2 membrane separation unit is provided with a second gas inlet, a carbon dioxide product gas outlet and a second high-pressure impermeable gas outlet, and the second gas inlet is connected with the first carbon dioxide enriched gas outlet; the N2 membrane separation unit is provided with a nitrogen enriched gas outlet, and a gas inletof the N2 membrane separation unit is connected with the first high-pressure impermeable gas outlet. The device has a high enrichment degree of carbon dioxide and can recover nitrogen, thereby avoiding resource waste.

Description

technical field [0001] The invention relates to the technical field of gas recovery, in particular to a combined capture and recovery device and method for carbon dioxide and nitrogen in flue gas. Background technique [0002] Global warming is one of the major environmental problems in the world at present. Among the various greenhouse gases that cause climate change, carbon dioxide (CO 2 ) has the greatest impact on global warming, controlling CO 2 Emission has become one of the important technical routes to deal with climate warming. CO produced by human activities 2 The largest part of emissions comes from coal-fired power generation, and the CO in the combustion tail gas of coal-fired power plants 2 The emission has the characteristics of low concentration, stability, concentration and large volume, and is a large-scale CO emission reduction 2 one of the best fields. At the same time, the tail gas also contains a large amount of nitrogen (N 2 ), the concentration ...

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Problems solved by technology

[0006] The main purpose of the present invention is to provide a combined capture and recovery device and method for carbon dioxide and nitrogen in flue gas, so as to solve the problem of using membrane separation method to capture and recover CO in flue gas in the prior art. 2 However, the enrichment degree is low, the process is complicated, the membrane separation efficiency is poor, and a large amount of enriched nitrogen is wasted.

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