Reinluft process

Regardless of method, desorption is never complete. Adsorbent capacity is always less following regeneration than it is on initial loading of adsorbent. Some adsorbable materials undergo chemisorption they chemically combine with the adsorbent. An example is the Reinluft process (52) for removing SO2 from flue gas on activated carbon. The SO2 is attached to the carbon as sulfuric acid. Desorption occurs only upon heating to 370°C a mixture of CO2, evolved from the chemically bound carbon, and SO2 are driven off. 

In the 1960s there were attempts to use a moving bed of carbon to remove sulphur dioxide from flue gas on a pilot scale. As described by Katell(46) and Cartelyou(47), this Reinluft process was abandoned because of the problems caused by the carbon igniting in the presence of oxygen. 

Reinluft A flue-gas desulfurization process using coke. The carbon acts as a catalyst for the oxidation of the sulfur dioxide to sulfur trioxide in the presence of water, and the sulfur trioxide is retained on the coke. The coke is regenerated in another vessel by heating with a hot gas stream, which reduces the sulfur trioxide back to sulfur dioxide and expels it for use in sulfuric acid manufacture. The key to this process is the inexpensive adsorbent. Developed by Reinluft GmbH and Chemiebau Dr. A. Zieren GmbH, and marketed as the Reinluft (Clean Air) Process. Four plants had been built by 1985. 

Using active carbons and some other carbonic adsorbents, several processes have been elaborated to output commercial products (sulphuric acid, sulphur, and sulphur dioxide), Reinluft (FRG), Hitashi (Japan), and Westvaco (USA). However, because of the deficit and high cost of adsorbents, these processes may be recommended only for purification of small volumes of ejected gases. Recently, the methods using natural acid-stable clinoptilolite- and mordenite-type zeolites as adsorbents have been introduced into industry. It is safe to say, however that general drawback of all granular physical adsorbents is their low sorption activity at a sufficiently low concentration of SO2 n g comparatively high aerodynamic resistance. 

In the Reinluft carbon adsorption process, the adsorbent is a slowly moving bed of carbon. The carbon is made from petroleum coke and activated by heating under vacuum at 1100°F (593°C). 

Furken, H., 1970, The Reinluft (Clean Air) Process for the Purification of Flue Gas from Power Stations, Proceedings of the American Power Conference, Vol. 32, No. 673. 

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