Abstract: A process for the expansion of tobacco, wherein in step (a) the tobacco is cooled by being mixed with cold carbon dioxide; (b) the cooled tobacco is impregnated with liquid carbon dioxide through treatment with gaseous carbon dioxide under a predetermined pressure; (c) the liquid carbon dioxide condensed in the tobacco is converted to solid carbon dioxide through pressure reduction; and (d) the tobacco containing solid carbon dioxide is subjected to a hot gas treatment to achieve the expansion. In step (a) the tobacco is cooled to a temperature of -30.degree. C. to -100.degree. C. through expansion of liquid carbon dioxide and the simultaneous mixing of the tobacco therewith.

Abstract: The gaseous discharge from a dry cleaning machine containing dry cleaning solvents is purified by passage through a gas/gas heat exchanger from which the gaseous flow enters a gas/liquid heat exchanger after having been cooled and partially dehumidified in the gas/gas heat exchanger. An accumulation cooling circuit acts on the gas/liquid heat exchanger to further cool and purify the gaseous flow coming from the gas/liquid heat exchanger, such flow then being returned into the gas/gas heat exchanger, where it is warmed therein by the incoming flow to be purified before returning into the dry cleaning machine.