Process and apparatus for compressing hydrogen gas in a centrifugal compressor

Patent metadata

Field	Value
Publication number	US-11773873-B2
Application number	US-202117201399-A
Country	US
Kind code	B2
Filing date	Mar 15, 2021
Priority date	Mar 15, 2021
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

A process for producing compressed hydrogen gas including: electrolysing water to produce hydrogen gas, and compressing the hydrogen gas in a multistage compression system including: a centrifugal compression stage and a recycle system for recycling a portion of the hydrogen gas from a product end to a feed end of the centrifugal compression stage; wherein hydrogen gas feed is fed to the feed end at a pre-determined feed temperature and pressure and mole fraction of water; wherein a portion of the hydrogen gas is removed from the product end, reduced in pressure in the recycle system to the pre-determined feed pressure and is then recycled to form at least part of the hydrogen gas feed to the centrifugal compression stage; and further including cooling hydrogen gas comprising the reduced pressure hydrogen gas such that the water mole fraction in the hydrogen gas feed is at the pre-determined water mole fraction.

First claim

The invention claimed is:

1. A process for producing compressed hydrogen gas, the process comprising:
electrolysing water to produce the hydrogen gas, and
compressing the hydrogen gas in a multistage compression system to produce compressed hydrogen gas;

the multistage compression system comprising:
a centrifugal compression stage with a feed end and a product end, and
a recycle system for recycling a portion of the hydrogen gas from the product end to the feed end of the centrifugal compression stage;

wherein hydrogen gas feed is fed to the feed end of the centrifugal compression stage at a pre-determined feed temperature and pressure and having a pre-determined mole fraction of water;
wherein a portion of the hydrogen gas is removed, as required, from the product end, reduced in pressure in the recycle system to the pre-determined feed pressure before any cooling step to provide reduced pressure hydrogen gas which is then recycled to form at least part of the hydrogen gas feed to the centrifugal compression stage; and
wherein the process comprises cooling the hydrogen gas comprising the reduced pressure hydrogen gas such that the mole fraction of water in the hydrogen gas feed is at the pre-determined mole fraction of water.

2. The process according to claim 1 , wherein the hydrogen gas comprising the reduced pressure hydrogen gas is cooled to a temperature within ±2° C. of the pre-determined feed temperature.

3. The process according to claim 1 , wherein the pre-determined feed temperature is from 20 to 60° C.

4. The process according to claim 1 , wherein the hydrogen gas feed to the centrifugal compression stage has an apparent molecular weight in a range from 2.2 to 3.5.

5. The process according to claim 1 , wherein the apparent molecular weight of the hydrogen gas comprising the reduced pressure hydrogen gas after cooling is equivalent to an apparent molecular weight of the hydrogen gas feed.

6. The process according to claim 1 , wherein the centrifugal compression stage is an initial stage of the multistage compression system.

7. The process according to claim 1 , wherein the multistage compression system comprises a first section and at least one further section downstream of the first section.

8. The process according to claim 1 , wherein the compressed hydrogen gas is consumed in at least one downstream process, and wherein during periods when more hydrogen gas is produced by the electrolysis than is required by the at least one downstream process(es), the process comprises feeding excess compressed hydrogen gas to storage, optionally after further compression; and
wherein during periods when more hydrogen gas is required by the at least one downstream process(es) than is produced by the electrolysis, the process comprises withdrawing compressed hydrogen gas from the storage and, after suitable pressure reduction, feeding said hydrogen gas from the storage to a stage of the multistage compression system.

9. The process according to claim 8 , wherein said hydrogen gas from the storage is fed to a stage of the multistage compression system by feeding it to an inter-cooler upstream of said stage.

10. The process according to claim 1 , wherein the hydrogen gas comprising the reduced pressure hydrogen gas is cooled in the recycle system.

11. The process according to claim 1 , wherein the hydrogen gas comprising the reduced pressure hydrogen gas is cooled in the hydrogen gas feed.

12. The process according to claim 1 , wherein the multistage compression system comprises:
a second centrifugal compression stage downstream of the centrifugal compression stage, the second centrifugal compression stage comprising a feed end and a product end,
a second recycle system for recycling a portion of the hydrogen gas from the product end to the feed end of the second centrifugal compression stage;

wherein the hydrogen gas feed is fed to the feed end of the second centrifugal compression stage at the pre-determined feed temperature and pressure and having the pre-determined mole fraction of water:
wherein a portion of the hydrogen gas is removed, as required, from the product end of the second centrifugal compression stage, reduced in pressure in the second recycle system to the pre-determined feed pressure before any cooling step to provide reduced pressure hydrogen gas which is then recycled to form at least part of the hydrogen gas feed to the second centrifugal compression stage; and
wherein the process comprises cooling hydrogen gas comprising reduced pressure hydrogen gas in the hydrogen gas feed to the second centrifugal compression stage such that the mole fraction of water in said hydrogen gas feed to the second centrifugal compression stage is at the pre-determined mole fraction of water.

13. An apparatus for producing compressed hydrogen gas, the apparatus comprising:
a plurality of electrolysers arranged in parallel for electrolysing water to provide hydrogen gas;
an electricity generation system for generating electricity to power the plurality of electrolysers, the electricity generation system being in electrically conductive communication with the plurality of electrolysers;
a multistage compression system for compressing the hydrogen gas to provide a compressed hydrogen gas, the multistage compression system comprising:
an inlet end, an outlet end and a centrifugal compression stage having a feed end and a product end, the inlet end being in fluid flow communication with the plurality of electrolysers via a feed header; and
a recycle system in fluid flow communication with the product end and the feed end of the centrifugal compression stage, the recycle system comprising: a valve for reducing the pressure of recycled hydrogen gas to a pre-determined feed pressure before any cooling step to provide reduced pressure hydrogen gas;

a cooler for cooling the hydrogen gas comprising the reduced pressure hydrogen gas in the recycle system and/or in the feed header to the centrifugal compression stage.

14. The apparatus according to claim 13 , wherein the multistage compression system comprises:
a second centrifugal compression stage downstream of the first centrifugal compression stage, the second centrifugal compression stage comprising a feed end and a product end and the feed end being in fluid flow communication with the product end of the first centrifugal compression stage via a feed header; and
a second recycle system in fluid flow communication with the product end and the feed end of the second centrifugal compression stage, the second recycle system comprising: a valve for reducing the pressure of recycled hydrogen gas to the pre-determined feed pressure for the second centrifugal compression stage before any cooling step to provide reduced pressure hydrogen gas;
a second cooler for cooling the hydrogen gas comprising the reduced pressure hydrogen gas in the feed header to the second centrifugal compression stage.

Assignees

• Air Prod & Chem

Inventors

• Wehrman Joseph Gerard
• Higginbotham Paul
• White Vincent

Classifications

• F04D29/5826 Primary

  Cooling at least part of the working fluid in a heat exchanger · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title

• C25B1/50

  Processes · CPC title

• F04B25/00

  Multi-stage pumps · CPC title

• F04D17/12

  Multi-stage pumps · CPC title