Method and device for separating carbon dioxide from an exhaust gas of a fossil fuel-powered power plant

摘要

The method comprises burning a fossil fuel in a combustion process (1) to produce carbon dioxide-containing exhaust gas (2), contacting the carbon dioxide-containing exhaust gas with an absorption medium (4) in an absorption process (3) to absorb carbon dioxide by the absorption medium such that a loaded absorption medium and a purified exhaust gas is formed, which is free from exhaust gas to a large extent, sub-dividing the loaded absorption medium into a first partial stream and a second partial stream, and supplying the first partial stream to a first desorption process (8). The method comprises burning a fossil fuel in a combustion process (1) to produce carbon dioxide-containing exhaust gas (2), contacting the carbon dioxide-containing exhaust gas with an absorption medium (4) in an absorption process (3) to absorb carbon dioxide by the absorption medium such that a loaded absorption medium and a purified exhaust gas is formed, which is free from exhaust gas to a large extent, sub-dividing the loaded absorption medium into a first partial stream and a second partial stream, supplying the first partial stream to a first desorption process (8), forming a first regenerated absorption medium and a first gas-vapor mixture from the gaseous carbon dioxide and vaporous absorption medium, supplying the second partial stream to a second desorption process (11), supplying a heat energy from the first desorption process to the second desorption process, and forming a second regenerated absorption medium and a second gas-vapor mixture from the gaseous carbon dioxide and vaporous absorption medium. The heat energy provided to the second desorption process is removed from the first gas-vapor mixture. The first desorption process is carried out at a first temperature (T1), which is highly adjusted than a second temperature (T2), in which the second desorption process is carried out. The first temperature is adjusted by a first pressure (P1) in the first desorption process. The first pressure is highly adjusted than a second pressure (P2) in the second desorption process. The second pressure is adjusted over a pumping process downstream to the second desorption process. The carbon dioxide is thermally driven in the desorption processes. The partial streams are adjusted and are divided in equal parts. The absorption medium is a liquid such as fluid, gas, aerosol or suspension. A vaporizable solvent is used as fluid and is a solution made of water and amine derivatives. The heat energy is supplied to the first desorption process through vapor. The vapor is guided with the loaded absorption medium into a heat exchanger in a first heat exchanging process. The heat in first and second preheating processes is removed from the first and second regenerated absorption medium, and is delivered to the first and second partial streams respectively. The separated carbon dioxide from the first desorption process is guided together with the carbon dioxide from the second desorption process. The separated carbon dioxide is compressed in a compression process to develop a compressed or liquefied carbon dioxide, which is stored. An independent claim is included for a fossil fuel-powered power plant.