- Rectisol
Rectisol is the trade name for a acid gas removal process that uses
methanol as a solvent to separateacid gas es such ashydrogen sulfide andcarbon dioxide from valuable feed gas streams. [cite book|author=Kohl, A, and Nielsen, R.|title=Gas Purification|edition=Fifth edition|publisher=Gulf Publishing Company|year=1997|id=] By doing so, the feed gas is made more suitable forcombustion and/or further processing. Rectisol is used most often to treatsynthesis gas (primarilyhydrogen andcarbon monoxide ) produced bygasification of coal or heavyhydrocarbons , as the methanol solvent is well able to remove trace contaminants such asammonia usually found in these gases.Process description
In the Rectisol process (licensed by
Lurgi AG ), cold methanol at approximately –40 °F (–40 °C) dissolves (absorbs) the acid gases from the feed gas at relatively high pressure, usually 400 to 1000 psia (2.76 to 6.89 MPa). The rich solvent containing the acid gases is then let down in pressure and/or steam stripped to release and recover the acid gases. The Rectisol process can operate selectively to recoverhydrogen sulfide andcarbon dioxide as separate streams, so that the hydrogen sulfide can be sent to aClaus unit for conversion to elementalsulfur , while at the same time the carbon dioxide can be sequestered or used for enhanced oil recovery.Rectisol, like
Selexol , is a physical solvent, unlike amine based acid gas removal solvents that rely on a chemical reaction with the acid gases. While the methanol solvent is inexpensive compared to the proprietary Selexol solvent, the Rectisol process is relatively complex and requires costlyrefrigeration to maintain the low temperatures required.References
External links
* [http://www.linde-engineering.com/process_plants/hydrogen_syngas_plants/gas_processing/rectisol_wash.php Rectisol Wash]
ee also
*
Hydrodesulfurization
*Selexol
*Amine treating
*Sour gas
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