Читать книгу Encyclopedia of Renewable Energy - James Speight G., James G. Speight - Страница 75

Alkali washing (often referred to as caustic scrubbing) for hydrogen sulfide removal with caustic scrubbing is only economical in small amounts if hydrogen sulfide is present and suitable means of disposing the spent solution are available. The chemistry is simples and to some extent, depending upon the concentration of hydrogen sulfide in the gas stream, efficient. Thus:

Carbonate washing is a mild alkali process for emission control by the removal of acid gases (such as carbon dioxide and hydrogen sulfide) from gas streams and uses the principle that the rate of absorption of carbon dioxide by potassium carbonate increases with temperature. It has been demonstrated that the process works best near the temperature of reversibility of the reactions:

In the Benfield process, acid gases are scrubbed from the feed in an absorber column using potassium carbonate solution with Benfield additives to improve performance and avoid corrosion.

Water washing, in terms of the outcome, is analogous to washing with potassium carbonate (Kohl and Riesenfeld, 1985), and it is also possible to carry out the desorption step by pressure reduction. The absorption is purely physical, and there is also a relatively high absorption of hydrocarbon derivatives, which are liberated at the same time as the acid gases.

See also: Gas Cleaning, Gas Processing, Gas Treating, Hot Potassium Carbonate Process, Scrubbing.