Method of operating downflow boiling point reactors in the selective hydrogenation of acetylenes and dienes

A process for the hydrogenation of acetylenes and dienes in a stream containing hydrogen, methane, C.sub.2-C.sub.6 olefins and paraffans, C.sub.2-C.sub.6 acetylenes, dienes, benzene, toluene, xylenes, and other C.sub.6+ components comprising the steps of:

• (a) passing said stream over a hydrogenation catalyst contained in a downflow boiling point reactor operated at the boiling point of the mixture in the reactor and the heat of reaction is absorbed by the boiling liquid to produce a first liquid/vapor effluent and a portion of the acetylenes and dienes are converted to their corresponding olefins and paraffins of the same carbon number;
• (b) separating the first liquid/vapor effluent to a first liquid and first vapor;
• (c) returning a portion of the first liquid to said downflow boiling point reactor in an amount to ensure that the catalyst is fully wetted at all positions within said downflow boiling point reactor;
• (d) condensing a portion of the first vapor corresponding to the mass evaporated in the reactor to produce a second liquid/vapor effluent;
• (e) separating the second liquid/vapor effluent to a second liquid and second vapor;
• (f) returning said second liquid to said downflow boiling point reactor, thereby controlling the steady state composition of the material flowing through the reactor;
• and
• (g) feeding said second vapor to a C5/C6 splitter where C5 and lighter material are taken as overheads and C6 and heavier material are taken as bottoms.