High pressure carbamate condenser

Patent metadata

Field	Value
Publication number	US-10857480-B2
Application number	US-201816469129-A
Country	US
Kind code	B2
Filing date	Oct 26, 2018
Priority date	Oct 27, 2017
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

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 ( 100 ) comprising shell-and-tube heat exchanger ( 101 ) which comprises a vessel ( 102 ) which comprises a shell ( 1 ) and at least one tube bundle ( 103 ), wherein the shell ( 1 ) encloses a vessel space ( 104 ), wherein the tube bundle ( 103 ) comprises tubes ( 2 ) having ends ( 3 ), and wherein a shell space ( 105 ) is provided between the tubes ( 2 ) and the shell ( 1 ),
wherein the heat exchanger further comprises a redistribution chamber ( 7 ) located in said vessel space ( 104 ), wherein said redistribution chamber comprises a wall ( 8 ) for separating a first fluid in the shell space ( 105 ) from a second fluid inside the redistribution chamber ( 7 ),
wherein a plurality of said tubes ( 2 a , 2 b ) are connected to a single redistribution chamber ( 7 ) such that said second fluid can flow between said tubes ( 2 a , 2 b ) and said redistribution chamber ( 7 ),
wherein the condenser ( 100 ) further comprises a duct ( 9 ) extending from an opening ( 10 ) for the second fluid in said shell ( 1 ) through said vessel space ( 104 ) to said redistribution chamber ( 7 ), such that the second fluid can flow between a tube end ( 3 ) and said opening ( 10 ) for the second fluid in said shell through said redistribution chamber ( 7 ) and said duct ( 9 ).

2. The high pressure carbamate condenser of claim 1 ,
configured for condensation of carbamate in the shell space ( 105 ),
wherein the vessel comprises a gas inlet ( 4 ) to the shell space ( 105 ) and an outlet ( 5 ) for liquid from the shell space ( 105 ),
wherein the vessel further comprises a gas distributor ( 6 ) connected to said gas inlet ( 5 ) for distributing gas to be condensed in the shell space.

3. The high pressure carbamate condenser of claim 2 ,
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.

4. The high pressure carbamate condenser of claim 3 , wherein the condenser is configured for being horizontally positioned in operation, wherein said tube comprise or consist of straight tube parts, and wherein said gas distributor and said straight tube parts are parallel arranged.

5. The high pressure carbamate condenser according of claim 2 , 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.

6. The high pressure carbamate condenser of 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.

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

8. The high pressure carbamate condenser of claim 7 ,
wherein the tube bundle contains U-shaped tubes wherein each tube has a bend and two legs, and 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.

9. A urea production plant comprising a high pressure urea synthesis section comprising a reactor, a stripper and the high pressure carbamate condenser of claim 1 , and wherein optionally the reactor and the high pressure carbamate condenser are combined in a single vessel which vessel has a liquid outlet connected to the stripper.

10. A urea production plant according to claim 9 , 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 and/or wherein said feed line is connected to the reactor for receiving a part of the urea solution from the reactor.

11. The urea production plant of claim 10 , 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.

12. The urea production plant of claim 10 , wherein said tube bundle is connected through a redistribution chamber and a duct to a gas/liquid separator having a liquid flow connection to a recovery section and a gas flow connection to a second condenser.

13. 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 the plant of claim 9 .

14. A urea production process according to claim 13 , wherein at least one of said ducts is on both the inside and the outside of the duct in contact with a solution containing carbamate, and wherein the tubes of at least one tube bundle are on both the inside and the outside in contact with a solution containing carbamate.

15. The urea production process of claim 14 , wherein the gas from the stripper is supplied to the shell space of the condenser, wherein at least a part of the stripped urea solution, and/or a part of the urea synthesis solution that is not sent to the stripper, is expanded while also comprising carbamate, and wherein at least part of the expanded urea solution is, optionally after gas/liquid separation, supplied to a tube bundle of the high pressure carbamate condenser through a duct and a redistribution chamber, and is heated in the tube bundle by heat exchange with the condensing process medium in the shell space, such that carbamate in said urea solution decomposes in the tube bundle.

16. The high pressure carbamate condenser of claim 4 , wherein the tube bundle contains U-shaped tubes wherein each tube has a bend and two legs.

17. The urea production plant of claim 12 , wherein said second condenser operates at medium pressure.

18. The urea production plant of claim 12 , wherein said second condenser is in heat exchanging contact with an evaporation section of the urea plant.

19. The urea production plant of claim 12 , wherein said second condenser has a liquid flow connection for carbamate recycle to the high pressure carbamate condenser.

Assignees

• Stamicarbon

Inventors

• Popa Dorin

Classifications

• C07C273/14 Primary

  Separation; Purification; Stabilisation; Use of additives · CPC title

• B01D3/343

  the substance being a gas · CPC title

• F28F21/083

  from stainless steel · CPC title

• F28F9/0202

  Header boxes having their inner space divided by partitions · CPC title

• F28D7/06 Primary

  the conduits having a single U-bend (F28D7/10 takes precedence){(F28D7/0016 and F28D7/0033 take precedence)} · CPC title