Abstract: A process for recovering olefins from a gas stream containing olefins and hydrogen. The process comprises compressing the gas stream in at least one compression stage to form a compressed gas stream, contacting the compressed gas stream with a membrane at conditions effective to obtain a permeate stream rich in hydrogen and a retentate stream depleted in hydrogen, and introducing the permeate stream into a pressure swing adsorption system at conditions effective to obtain a nonadsorbed stream rich in hydrogen and a desorbed stream comprising olefins.

Abstract: A process for recovering olefins from a cracking effluent containing olefins and hydrogen. The process comprises compressing the cracking effluent in at least one compression stage to form a compressed cracking effluent, contacting the compressed cracking effluent with a membrane at conditions effective to obtain a permeate stream rich in hydrogen and a retentate stream depleted in hydrogen, and introducing the permeate stream into a pressure swing adsorption system at conditions effective to obtain a nonadsorbed stream rich in hydrogen and a desorbed stream comprising olefins.

Abstract: C.sub.4 hydrocarbons are separated from a gaseous mixture containing the same and lower hydrocarbons and hydrogen, by cooling such a gaseous mixture (45) to a temperature between -60.degree. F. and +32.degree. F. until a portion of the C.sub.4 hydrocarbons is condensed. The mixture of gas and liquid C.sub.4 hydrocarbons thus produced is phase separated in a first phase separation (53), and the liquid from this first phase separation is withdrawn as C.sub.4 hydrocarbons product (69). Gas from the first phase separation (53) is further cooled (47) until substantially all of the remaining C.sub.4 hydrocarbons are condensed but not the hydrogen. The latter material is subjected to a second phase separation (75), and liquid from the second phase separation (77) is withdrawn as liquid C.sub.4 hydrocarbons product (69).

Abstract: C.sub.4 hydrocarbons are separated from a gaseous mixture containing the same and lower hydrocarbons and hydrogen, by cooling such a gaseous mixture (45) to a temperature between -60.degree. F. and +32.degree. F. until a portion of the C.sub.4 hydrocarbons is condensed. The mixture of gas and liquid C.sub.4 hydrocarbons thus produced is phase separated in a first phase separation (53), and the liquid from this first phase separation is withdrawn as C.sub.4 hydrocarbons product (69). Gas from the first phase separation (53) is further cooled(47) until substantially all of the remaining C.sub.4 hydrocarbons are condensed but not the hydrogen. The latter material is subjected to a second phase separation (75), and liquid from the second phase separation (77) is withdrawn as liquid C.sub.4 hydrocarbons product (69).

Abstract: Demoisturizing composition used for the displacement of liquid water, comprising a chlorofluorocarbon that is liquid at room temperature, containing a surface-active agent responding to the formula: ##STR1## in which R is an alkyl group in C.sub.6 -C.sub.18R' is an alkyl group in C.sub.1 to C.sub.2R" is an alkyl group in C.sub.1 to C.sub.18p is a value ranging between 1 and 2characterized in that the surface-active composition is prepared by mixing the following three constituents: ##STR2## where R.sub.F represents a straight or branched perfluorinated alkyl chain of formula C.sub.q F.sub.2q+1 in which q is a whole number ranging between 2 and 20 and where X is a divalent bond group that may be partially halogenated and R.sub.1 and R.sub.2 represent a hydrogen atom, an alkyl radical or a hydroxyalkyl radical, containing less than 6 carbon atoms.