Catalytic dehydrogenation process

A catalytic dehydrogenation process which comprises the steps of:

• (a) charging a C.sub.2 -C.sub.6 paraffinic hydrocarbon into a reaction zone in admixture with hydrogen and contacting said mixture therein with a dehydrogenation catalyst at dehydrogenation conditions of temperature and pressure effecting the formation of a reaction zone effluent stream comprising hydrogen, an olefinic hydrocarbon product, and unreacted paraffinic hydrocarbon;
• (b) compressing and cooling said effluent stream to a pressure and temperature effecting the formation of a liquid phase comprising said hydrocarbons and a hydrogen-rich vapor phase, and introducing said effluent stream into a gas-liquid separation zone maintained at said conditions of temperature and pressure;
• (c) recovering said hydrocarbon phase;
• (d) recovering one portion of said vapor phase substantially equivalent to the net hydrogen make;
• (e) expanding the remaining portion of said vapor phase and effecting a substantial reduction in the pressure and temperature thereof;
• (f) passing the thus cooled vapor phase in indirect heat exchange relationship with the effluent stream of step (b) to promote said temperature conditions in said gas-liquid separation zone;
• (g) thereafter combining one portion of the vapor phase with the effluent stream from step (a) whereby said vapor phase is recycled to said gas-liquid separation zone to control the amount of vapor expanded in accordance with step (e) and the temperature of said separation zone in accordance with step (f);
• and,
• (h) recycling the remaining portion of the hydrogen-rich vapor phase to said reaction zone in admixture with the paraffinic hydrocarbon charged thereto in accordance with step (a).