US Patent 7300498 Regeneration of adsorption beds using heated nitrogen

A system and method for removal of solvents, or other materials, from an exhaust stream, uses an active adsorption bed and a bed that is periodically regenerated. Electrically heated nitrogen may be used to regenerate the beds. A portion of the exhaust stream to be cleaned is diverted to a heat exchanger, so as to pre-heat the nitrogen used for regeneration. Liquid nitrogen, preferably from the same source as that used to provide gas for regeneration, is directed to the active bed, lowering its temperature and increasing its efficiency. The invention avoids the need for the use of steam to heat the nitrogen, and provides a system that is more efficient than those known in the prior art.