A liquid/gas reactor includes a bulk catalyst bed and means for supplying fresh feed and recycled at least partially converted liquid product stream to the bulk catalyst bed. The reactor also includes means for collecting an at least partially converted liquid product stream from the bulk catalyst bed and recycling at least a portion thereto. A minor catalyst bed extends substantially vertically through the bulk catalyst bed. Means for supplying recycled at least partially converted product stream only to the minor catalyst bed is also provided. A separating wall is disposed between the bulk catalyst bed and the minor catalyst bed.
1. A liquid/gas reactor comprising:
(a) a bulk catalyst bed and means for supplying fresh feed and recycled at least partially converted liquid product stream to said bulk catalyst bed;
(b) means for collecting an at least partially converted liquid product stream from said bulk catalyst bed and recycling at least a portion thereof to step (a);
(c) a minor catalyst bed extending substantially vertically through the bulk catalyst bed and means for supplying recycled at least partially converted product stream only to said minor catalyst bed; and
(d) a separating wall between said bulk and said minor catalyst bed.
2. A reactor according to claim 1 wherein the minor catalyst bed is located such that it is central to the bulk catalyst bed which forms on annulus therearound.
3. A reactor according to claim 1 wherein all of the partially converted product stream is recycled with a portion being recycled to the bulk catalyst bed and a portion being passed to the minor catalyst bed.
4. A reactor according to claim 1 wherein the reactor additionally includes a heater or cooler on the recycled, at least partially converted, liquid product stream.
5. A reactor according to claim 1 wherein the beds are operated at different temperatures.
6. A reactor according to claim 5 wherein the separation wall is fabricated from insulating material.
7. A reactor according to claim 1 wherein the ratio of the minor catalyst bed to the bulk catalyst bed will be from about half to about twice the ratio of the flowrates of recycle to the minor bed to the feed plus the recycle to the bulk bed.
8. A reactor according to claim 7 wherein the ratio is substantially 1:1.
9. A reactor according to claim 1 where the catalyst in the minor catalyst bed is different to the catalyst in the major catalyst bed.
10. A process for a gas/liquid reaction comprising the steps of:
(a) supplying feed comprising fresh feed and recycle product stream to the bulk catalyst bed of claim 1 ;
(b) plying gas to the reactor of claim 1 ;
(c) allowing reaction to occur in the bulk catalyst bed;
(d) collecting an at least partially converted liquid product steam;
(e) recycling at least a portion of said partially converted liquid product stream to the bulk catalyst bed;
(f) supplying at least a portion of said partially converted liquid product stream to the minor catalyst bed of claim 1 ;
(g) allowing reaction to occur in the minor catalyst bed; and
(h) collecting the product stream from the minor catalyst bed.
11. The process according to claim 10 wherein the partially reacted stream returned to the reactor is heated or cooled before being recycled.
12. The process according to claim 10 for the hydrogenation of an aldehyde to alcohol.
13. The process according to claim 10 for the selective hydrogenation of a diene or an alkyne to an olefin.
14. The process according to claim 13 wherein the diene is butadiene.
15. The process according to claim 10 for the hydrogenation of the aromatic ring in an aromatic compound.