Aldehyde production process with multi-stage condensation
View Patent ↗A hydroformylation system for making aldehyde by reacting olefin with synthesis gas by way of hydroformylation is improved by multi-stage condensation of gaseous reactor effluent for providing liquid feed to a gas-liquid contact zone. The process provides for condensing and separating the gaseous reactor output stream in a plurality of successive condenser stages into gaseous condenser output streams and liquid condenser output streams having differing temperatures and feeding the recovered liquid to the gas-liquid contact zone to improve olefin recovery by stripping.
1. A method of recovering a crude aldehyde product stream from a gaseous stream containing aldehyde and unreacted olefin from a hydroformylation system comprising:
(a) condensing and separating the gaseous stream in a first condenser stage into (i) a first condenser stage liquid product stream at a first temperature and (ii) a first condenser stage gaseous output stream;
(b) condensing and separating at least a portion of the first condenser stage gaseous output stream in a second condenser stage into (i) a second condenser stage liquid product stream at a second temperature lower than said first temperature of said first condenser stage liquid stream and (ii) a second condenser stage gaseous output stream;
(c) feeding at least both of the first condenser stage liquid stream and the second condenser stage liquid stream as liquid feed to a gas-liquid contact zone in order to adjust a liquid feed temperature to the gas-liquid contact zone;
(d) stripping unreacted olefin from the liquid feed with synthesis gas in said gas-liquid contact zone; and
(e) recovering a crude liquid aldehyde product stream from said gas-liquid contact zone having a lower olefin content than the liquid feed to said gas-liquid contact zone.
2. The method according to claim 1 , wherein the liquid feed temperature to the gas-liquid contact zone is at a temperature intermediate the first temperature of the first condenser stage product stream and the second temperature of the second condenser stage product stream.
3. The method according to claim 1 , wherein said first condenser stage liquid stream and said second condenser stage liquid stream are combined prior to providing them to the gas-liquid contact zone.
4. The method according to claim 1 , wherein the liquid feed temperature is between 68° C. and 85° C.
5. The method according to claim 1 , wherein the first condenser stage liquid stream is at a temperature of from 70° C. to 105° C.
6. The method according to claim 1 , wherein the second condenser stage liquid stream is at a temperature of from 50° C. to 70° C.
7. The method according to claim 1 , wherein the first condenser stage liquid stream and the second condenser stage liquid stream are supplied to the gas-liquid contact zone without external heating.
8. The method according to claim 1 , wherein the ratio of unreacted olefin to aldehyde in the crude liquid aldehyde product stream is less than 1 g olefin/kg aldehyde.
9. Apparatus for recovering a crude aldehyde product stream from a gaseous stream containing aldehyde and unreacted olefin withdrawn from a hydroformylation reactor comprising:
(a) a plurality of successive condenser stages including a first and last condenser stage, each of which condenser stages is adapted for condensing and separating the gaseous stream into a liquid product stream and a gaseous output stream thereby generating a (i) a plurality of staged liquid product streams at successively lower temperatures and (ii) a plurality of staged gaseous output streams at successively lower temperatures;
(b) a gas-liquid contact zone ducted directly to said plurality of staged liquid product streams in order to receive said plurality of staged liquid product streams in order to adjust a liquid feed temperature to said gas-liquid contact zone, said gas-liquid contact zone being configured and adapted to strip unreacted olefin from the liquid feed with synthesis gas in said gas-liquid contact zone as well as provide a crude liquid aldehyde product stream from said gas liquid contact zone having a lower olefin content than the liquid feed.
10. The apparatus according to claim 9 , wherein the liquid feed temperature to said gas-liquid contact zone is at a temperature below a temperature of the first condenser stage liquid product stream and above a temperature of the last condenser stage liquid product stream.
11. The apparatus according to claim 9 , wherein said plurality of successive condenser stages consists of two successive condenser stages.
12. The apparatus according to claim 9 , wherein said plurality of successive condenser stages consists of three successive condenser stages.
13. The apparatus according to claim 9 , wherein said plurality of successive condenser stages consists of four successive condenser stages.
14. The method according to claim 1 , wherein the olefin is propylene and the aldehyde product is butyraldehyde.
15. The method according to claim 2 , wherein the olefin is propylene and the aldehyde product is butyraldehyde.
16. The method according to claim 3 , wherein the olefin is propylene and the aldehyde product is butyraldehyde.
17. The method according to claim 4 , wherein the olefin is propylene and the aldehyde product is butyraldehyde.
18. The method according to claim 1 , wherein the olefin is ethylene and the aldehyde product is propionaldehyde.
19. The method according to claim 2 , wherein the olefin is ethylene and the aldehyde product is propionaldehyde.
20. The method according to claim 3 , wherein the olefin is ethylene and the aldehyde product is propionaldehyde.