Production and recovery of linear mono-olefins

Claim 1

In a process for dehydrogenating a hydrocarbon charge stock, consisting essentially of normal paraffins having from about 3 to about 20 carbon atoms per molecule to form linear mono-olefins the sequential steps of: (a) reacting said charge stock in the presence of hydrogen, in a dehydrogenation reaction zone, at dehydrogenation conditions selected to convert paraffinic hydrocarbons to linear mono-olefinic hydrocarbons; (b) separating the resulting dehydrogenation zone effluent, in a first separation zone, at separating conditions to provide (1) a hydrogen-rich, principally vaporous phase containing olefinic hydrocarbons and, (2) a second phase containing linear mono-olefinic hydrocarbons and unreacted normal paraffins; (c) separating said second phase, in a second separation zone to (1) recover said linear mono-olefinic hydrocarbons, and (2) provide a normal paraffin concentrate containing olefinic hydrocarbons; (d) reacting at least a portion of said hydrogen-rich vaporous phase, in a hydrotreating zone, at hydrotreating conditions selected to saturate the olefinic hydrocarbons therein; and, (e) introducing the resulting substantially olefin-free effluent from said hydrotreating reaction zone into said dehydrogenation reaction zone.