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.); and
feeding at least a first portion of the compressed carbon dioxide-rich gas to a gasifier.
2. The method as set forth in claim 1 , wherein upon gasification, a second syngas mixture is produced, said method further comprises cooling the second syngas mixture in a radiant syngas cooler.
3. The method as set forth in claim 2 further comprising supplying the cooled second syngas mixture to a syngas scrubber.
4. The method as set forth in claim 3 further comprising:
cooling the scrubbed syngas mixture discharged from the syngas scrubber; and
channeling the cooled scrubbed syngas mixture to the separation device.
5. The method as set forth in claim 2 further comprising contacting the second syngas mixture with a second portion of compressed carbon dioxide-rich gas in the radiant syngas cooler to facilitate cooling the second syngas mixture.
6. The method as set forth in claim 5 further comprising:
contacting the cooled second syngas mixture with a third portion of compressed carbon dioxide-rich gas to form a mixture; and
channeling the mixture to a convective syngas cooler.
7. 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.
8. The method as set forth in claim 1 , wherein said feeding the first portion of compressed carbon dioxide-rich gas facilitates increasing carbon conversion by up to about 3%.
9. The method as set forth in claim 1 , wherein said feeding the first portion of compressed carbon dioxide-rich gas facilitates reducing oxygen consumption per unit of syngas production by up to about 2%.
10. 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.