Method and apparatus for purifying a gas stream in a sorption filter

Claim 1

Method for the purification by adsorption in a sorption medium of a gas stream loaded with organic gases or vapors, especially up to near the saturation limit, in a sorption filter, which comprises circulating a gas in a loop through a sorption medium layer, introducing a gas stream to be purified containing organic impurities from a source outside of the loop into the circulating gas stream at a point in the loop prior to passage through the sorption medium layer, maintaining a volumetric flow of the circulating gas which is larger than the volumetric flow of the gas to be purified introduced into the circulating gas stream passing the mixture of circulating gas and gas containing organic impurities through the sorption medium layer to remove organic impurities, withdrawing a portion of said purified mixture of gases after passage through the sorption medium layer, maintaining a volumetric flow of said portion of gases which substantially corresponds to the volumetric flow of the gas to be purified, and continuing the circulation of the remainder of the purified mixture of gases as circulating gas to the mixing point to be mixed with gas to be purified and circulating this mixture of gases to the sorption medium layer.