Methods of recycling carbon dioxide to the gasification system
View Patent ↗Method of producing syngas in an IGCC system, comprising compressing and heating carbon dioxide-rich gas to produce heated compressed carbon dioxide-rich gas, mixing the heated compressed carbon dioxide-rich gas with oxygen and feedstock to form a feedstock mixture, subjecting the feedstock mixture to gasification to produce syngas, cooling the syngas in a radiant syngas cooler, contacting syngas cooled in the radiant syngas cooler with compressed carbon dioxide-rich gas to further cool the syngas, and removing an amount of carbon dioxide-rich gas from the product mixture and compressing the removed carbon dioxide-rich gas prior to mixing with oxygen and feedstock.
1. A method of recycling carbon dioxide from a first syngas mixture of a gasification system, said method comprising:
removing carbon dioxide-rich gas from the first syngas mixture in a separation device;
compressing the carbon dioxide-rich gas;
heating the compressed carbon dioxide-rich gas to a temperature of between about 550° F. (278.8° C.) to about 700° F. (371.1° C.);
producing a second syngas mixture in a gasifier;
mixing the second syngas mixture and at least a first portion of compressed carbon dioxide-rich gas to form a combined syngas mixture; and
channeling the combined syngas mixture into a radiant syngas cooler to facilitate cooling the second syngas mixture.
2. The method as set forth in claim 1 further comprising:
channeling the cooled second syngas mixture into a syngas scrubber;
cooling the scrubbed syngas mixture; and
channeling the cooled scrubbed syngas mixture to the separation device.
3. The method as set forth in claim 1 further comprising:
contacting the cooled second syngas mixture with a second portion of compressed carbon dioxide-rich gas to form a mixture; and
channeling the mixture to a convective syngas cooler.
4. The method as set forth in claim 1 further comprising heating the compressed carbon dioxide-rich gas prior to channeling the second syngas mixture and the first portion of compressed carbon dioxide-rich gas to the radiant syngas cooler.
5. The method as set forth in claim 1 , wherein said removing carbon dioxide-rich gas from the first syngas mixture in a separation device comprises removing from about 15% (by total moles carbon dioxide present in the first syngas mixture) to about 50% (by total moles carbon dioxide present in the first syngas mixture) carbon dioxide-rich gas.
6. The method as set forth in claim 1 , wherein the first portion of the compressed carbon dioxide-rich gas is combined with at least one of oxygen and feedstock to form a feedstock mixture.