Tail gas heating within PSA surge tank

Patent metadata

Field	Value
Publication number	US-10745276-B2
Application number	US-201816023374-A
Country	US
Kind code	B2
Filing date	Jun 29, 2018
Priority date	Jun 29, 2018
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

The present invention relates to a method of improving the efficiency of an integrated hydrogen generation system by the introduction of a means to heat the PSA tail gas within the PSA surge tank.

First claim

We claim:

1. A method of improving the efficiency of an integrated hydrogen generation system comprising:
producing a syngas stream in a steam reformer which has a combustion zone;
introducing at least a portion of the syngas stream to a water gas shift reactor;
cooling the shifted syngas stream to produce a cooled shifted syngas stream;
introducing the cooled shifted syngas stream into a pressure swing adsorption unit, thereby producing a stream of predominantly hydrogen and a tail gas comprising predominantly byproducts;
routing said tail gas to one or more surge tank(s) having a heat exchange device disposed therein and indirectly heating said tail gas by passing it over a surface of said heat exchange device inside which a hot fluid is cooled, thereby obtaining a heated tail gas; and
routing said heated tail gas to the combustion zone of a reformer.

2. The method of claim 1 , wherein a heated tail gas temperature ranges from about 150 to 500° F.

3. The method of claim 1 , wherein the heat exchange device is a coil, or a heat exchanger.

4. The method of claim 1 , wherein the hot fluid flowing through the heat exchange device disposed in the surge tank is a saturated or superheated low pressure steam stream from 225 to 400° F.

5. The method of claim 1 , wherein the hot fluid flowing through the heat exchange device disposed in the surge tank is a saturated or superheated high pressure steam stream from 350 to 800° F.

6. The method of claim 1 , wherein the hot fluid flowing through the heat exchange device disposed in the surge tank is heated water.

7. The method of claim 1 , wherein the hot fluid flowing through the heat exchange device disposed in the surge tank is syngas generated in the steam reformer.

8. The method of claim 1 , wherein the hot fluid flowing through the heat exchange device disposed in the surge tank is imported from outside of a hydrogen generation system.

9. The method of claim 1 , further comprising mixing the tail gas inside the surge tank to obtain a near homogeneous mixing with a Wobbe index variation of +/−5%.

10. The method of claim 1 , wherein the cooled shifted syngas stream is routed to the pressure swing adsorption unit at pressure ranging from 150 to 500 psig.

11. The method of claim 1 , wherein the heated tail gas routed to the combustion zone of the reformer is withdrawn from the surge tank at a pressure of between 1 and 50 psig.

12. The method of claim 11 , wherein the heated tail gas routed to the combustion zone of the reformer is withdrawn from the surge tank at a pressure of between 2 and 7 psig.

13. The method of claim 1 , wherein the tail gas comprises methane, water and other impurities.

Assignees

• Warta Andrew
• Kalp Bryan S
• Raybold Troy M
• Dmevich Raymond F
• Praxair Technology Inc

Inventors

• Warta Andrew
• Kalp Bryan S
• Raybold Troy M
• Dmevich Raymond F

Classifications

• C01B2203/1241

  Natural gas or methane · CPC title

• C01B2203/0894

  Generation of steam · CPC title

• C01B2203/0883

  by indirect heat exchange · CPC title

• C01B2203/0827

  at least part of the fuel being a recycle stream · CPC title

• C01B2203/0816

  Heating by flames · CPC title