High pressure carbamate condenser

Patent metadata

Field	Value
Publication number	US-11766627-B2
Application number	US-202217724085-A
Country	US
Kind code	B2
Filing date	Apr 19, 2022
Priority date	Oct 27, 2017
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

Described are a high pressure carbamate condenser, urea plant, and urea production process. The high pressure carbamate condenser as described is of the shell-and-tube heat exchanger type with a tube bundle and has a redistribution chamber connected to tubes of the tube bundle and to a duct. The duct extends between the redistribution chamber and the shell.

First claim

The invention claimed is:

1. A high pressure carbamate condenser comprising a shell-and-tube heat exchanger which comprises a vessel which comprises a shell and at least one tube bundle, wherein the shell encloses a vessel space, wherein the tube bundle comprises tubes having ends, and wherein a shell space is provided between the tubes and the shell,
wherein the heat exchanger further comprises a redistribution chamber located in said vessel space, wherein said redistribution chamber comprises a wall for separating a first fluid in the shell space from a second fluid inside the redistribution chamber,
wherein a plurality of said tubes are connected to a single redistribution chamber such that said second fluid can flow between said tubes and said redistribution chamber,
wherein the condenser further comprises a duct extending from an opening for the second fluid in said shell through said vessel space to said redistribution chamber, such that the second fluid can flow between a tube end and said opening for the second fluid in said shell through said redistribution chamber and said duct, wherein the duct has a first duct end connected with a wall of the redistribution chamber and a second end connected with the shell, wherein the high pressure carbamate condenser is configured for condensation of carbamate in the shell space,
wherein the vessel comprises a gas inlet to the shell space and an outlet for liquid from the shell space,
wherein the vessel further comprises a gas distributor connected to said gas inlet for distributing gas to be condensed in the shell space, wherein the condenser comprises at least two of said ducts including an inlet duct and an outlet duct, and comprises at least two of said redistribution chambers, including an inlet redistribution chamber for distributing cooling fluid feed from said inlet duct to a plurality of tubes and an outlet redistribution chamber for combining heated cooling fluid from a plurality of tubes to said outlet duct,
wherein the condenser is configured for being horizontally positioned in operation, wherein said tubes comprise straight tube parts, and wherein said gas distributor and said straight tube parts are parallel arranged, and wherein the tube bundle contains U-shaped tubes wherein each tube has a bend and two legs, wherein said legs are said straight tube parts;
wherein the condenser comprises a reactor part between the bend of the U-shaped tube bundle and the shell.

2. The high pressure carbamate condenser according claim 1 , wherein the legs are straight parts of the tubes having a length of 20% to 60% of the length of the vessel.

3. The high pressure carbamate condenser according claim 1 , wherein the shell comprises an essentially cylindrical middle part and two cap parts closing said middle part at opposed ends,
and wherein said shell space is a single shell space defined by said middle part and cap parts such that fluid can flow from said gas distributor to both of said cap parts.

4. The high pressure carbamate condenser according to claim 1 , wherein the redistribution chamber comprises a plurality of elements providing the wall of the redistribution chamber, and wherein at least one of said elements is openable and closable, for providing access to the inside of the redistribution chamber.

5. The high pressure carbamate condenser according to claim 1 ,
wherein a plurality of said redistribution chambers are stacked on each other,
and wherein a plate element with bore holes is common to said plurality of redistribution chambers.

6. The high pressure carbamate condenser according to claim 5 ,
wherein said plurality of redistribution chambers includes an inlet redistribution chamber and an outlet redistribution chamber of the same U-shaped tube bundle, arranged in the same stack of redistribution chambers.

7. The high pressure carbamate condenser according to claim 1 , wherein the first duct end is aligned with an opening in the wall and the second duct end is aligned with an opening in the shell, such that fluid can flow from outside the shell to the redistribution chamber through the duct; wherein the duct is at least in part located in the vessel; wherein the first duct end is located in the vessel; wherein the duct extends through the vessel space, and wherein the outer surface of the duct is exposed to the shell space.

8. The high pressure carbamate condenser according claim 1 , wherein the shell space includes baffles dividing the shell space into compartments that are not completely sealed off from each other.

9. The high pressure carbamate condenser according claim 8 , wherein a most downstream baffle has no opening in it, such that in operation liquid condensate flows over the baffle top to the liquid outlet in the shell.

10. The high pressure carbamate condenser according to claim 1 , wherein the redistribution chambers are spaced apart from the shell.

11. A urea production plant comprising a high pressure urea synthesis section comprising a reactor, a stripper and a high pressure carbamate condenser, wherein the high pressure carbamate condenser is according to claim 1 and wherein the reactor and the high pressure carbamate condenser are combined in the vessel which vessel comprises the liquid outlet for liquid from the shell space connected to the stripper.

12. The urea production plant according to claim 11 , wherein the high pressure carbamate condenser comprises a tube bundle that is connected through a redistribution chamber and a duct to a feed line for urea solution that also contains carbamate, wherein said feed line is connected to the stripper for receiving stripped urea solution from the stripper; wherein the high pressure carbamate condenser is configured for condensation of carbamate in the shell space, wherein the vessel comprises a gas inlet to the shell space and an outlet for liquid from the shell space, wherein the vessel further comprises a gas distributor connected to said gas inlet for distributing gas to be condensed in the shell space.

13. The urea production plant according to claim 12 , wherein the feed line comprises an expansion device and a gas/liquid separator for separating gas from the expanded urea solution, and wherein the feed line is configured for supplying at least a part of said expanded urea solution to said duct.

14. The urea production plant according to claim 12 , wherein said tube bundle is connected through said redistribution chamber and said duct to a gas/liquid separator having a liquid flow connection to a recovery section and a gas flow connection to a second condenser.

15. The urea production plant according to claim 14 wherein said second condenser operates at medium pressure.

16. The urea production plant according to claim 15 wherein the second condenser is in heat exchanging contact with an evaporation section of the urea plant.

17. The urea production plant according to claim 14 wherein said second condenser has a liquid flow connection for carbamate recycle to the high pressure carbamate condenser.

18. A urea production process wherein urea is formed in a reactor to give urea synthesis solution, at least a part of said urea synthesis solution is stripped in a stripper to give stripped urea solution, and wherein gas from the stripper is condensed in a high pressure carbamate condenser, wherein the process is carried out in a plant according to claim 11 .

19. The urea production process according to claim 18 , wherein at least one of said ducts is on both the inside and the outside of the duct in contact wit

Assignees

• Stamicarbon

Inventors

• Popa Dorin

Classifications

• B01D5/0075 Primary

  with heat exchanging (B01D5/0039 takes precedence) · CPC title

• B01D5/0009

  Horizontal tubes · CPC title

• B01D5/0081

  Feeding the steam or the vapours · CPC title

• B01D5/0087

  Recirculating of the cooling medium · CPC title

• B01D5/0093

  Removing and treatment of non condensable gases · CPC title