Systems and methods for production and separation of hydrogen and carbon dioxide

Patent metadata

Field	Value
Publication number	US-11066298-B2
Application number	US-201816185188-A
Country	US
Kind code	B2
Filing date	Nov 9, 2018
Priority date	Nov 9, 2017
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

The present disclosure relates to systems and methods useful for providing one or more chemical compounds in a substantially pure form. In particular, the systems and methods can be configured for separation of carbon dioxide from a process stream, such as a process stream in a hydrogen production system. As such, the present disclosure can provide systems and method for production of hydrogen and/or carbon dioxide.

First claim

The invention claimed is:

1. A process for hydrogen production, the process comprising:
reacting a hydrocarbon feed and oxygen in a reactor unit to form a product gas stream comprising H 2 +CO;
passing at least a portion of the product gas stream comprising H 2 +CO through a steam generating boiler to add steam to the product gas stream comprising H 2 +CO;
converting the product gas stream comprising H 2 +CO in at least one reactor to form CO 2 and thus form a stream comprising H 2 +CO 2 ;
processing the stream comprising H 2 +CO 2 in a pressure swing adsorber, wherein the stream comprising H 2 +CO 2 processed in the pressure swing adsorber comprises at least 40 mol % CO 2 , to separate out H 2 and provide a product stream formed of substantially pure hydrogen and also provide an H 2 -depleted waste gas stream comprising the CO 2 formed in the at least one reactor;
forming a liquid CO 2 product stream in a low temperature separation unit operating with auto-refrigeration by passing the H 2 -depleted waste gas stream comprising CO 2 therethrough such that at least 50 mol % of the CO 2 in the waste gas stream comprising CO 2 is separated into the liquid CO 2 product stream; and
recycling a vapor phase stream from the low temperature separation unit.

2. The process of claim 1 , wherein the low temperature separation unit operating with auto-refrigeration operates without using an external refrigerant.

3. The process of claim 1 , wherein the low temperature separation unit comprises:
a drier configured for removing moisture from the waste gas stream comprising CO 2 ;
at least one heat exchanger configured for cooling the waste gas stream comprising CO 2 against one or more cooling streams and providing the waste gas stream comprising CO 2 as a two-phase stream; and
at least one expander configured for cooling the two-phase stream via expansion of the two-phase stream.

4. The process of claim 3 , wherein the low temperature separation unit further comprises
a compressor configured for compressing the waste gas stream comprising CO 2 , the compressor being positioned upstream from the drier; and
a separator configured for separating the two-phase stream into the vapor phase stream and the liquid CO 2 product stream.

5. The process of claim 1 , wherein a portion of the waste gas stream comprising CO 2 exiting the pressure swing adsorber is compressed and recycled back to the reactor unit.

6. The process of claim 1 , wherein at least a portion of the vapor phase stream from the low temperature separation unit is recycled back to the reactor unit.

7. The process of claim 1 , wherein the vapor phase stream from the low temperature separation unit is processed through a second pressure swing absorber to remove at least a portion of any H 2 present in the vapor phase stream prior to recycling of the vapor phase stream from the low temperature separation unit.

8. The process of claim 1 , comprising removing at least a portion of any argon and nitrogen present in one or both of the product gas stream comprising H 2 +CO and the stream comprising H 2 +CO 2 prior to entry of the stream comprising H 2 +CO 2 into the pressure swing absorber such that the total concentration of argon and nitrogen in the stream comprising H 2 +CO 2 at an inlet of the pressure swing adsorber is in the range of about 3 mol % to about 12 mol %.

9. The process of claim 1 , wherein at least 80 mol % of the CO 2 in the waste gas stream comprising CO 2 is separated into the liquid CO 2 product stream.

10. The process of claim 1 , wherein forming the liquid CO 2 product stream in the low temperature separation unit comprises:
providing the waste gas stream comprising CO 2 at a pressure such that a partial pressure of the CO 2 in the process stream is at least 15 bar;
drying the waste gas stream comprising CO 2 sufficiently so that a dew point of the waste gas stream comprising CO 2 is reduced to a temperature of about −20° C. or less;
cooling the waste gas stream comprising CO 2 in at least one heat exchanger to provide the waste gas stream comprising CO 2 as a two phase stream;
expanding the two phase stream so as to reduce the temperature of the two phase stream to a temperature that is within about 15° C. of a freezing point of the two phase stream; and
separating the two phase stream to provide the vapor phase stream and to provide the liquid CO 2 product stream.

11. The process of claim 1 , wherein the vapor phase stream from the low temperature separation unit is passed through a catalytic CO shift unit with an economizer heat exchanger, has steam added thereto, and is then passed through a catalytic reactor to convert at least a portion of the contained CO by reaction with the steam to form a further stream comprising H 2 +CO 2 and to form a gas stream containing at least 60 mol % Hz.

12. The process of claim 1 , wherein the reactor unit comprises a partial oxidation reactor unit arranged to receive the oxygen and a first stream of the hydrocarbon feed and produce synthesis gas, and a reformer in fluid communication with the partial oxidation reactor unit.

13. The process of claim 12 , further comprising receiving, at the reformer, the synthesis gas from the partial oxidation reactor, a second stream of the hydrocarbon feed, and a steam stream from at least one heat exchanger so as to form the product gas stream comprising H 2 +CO.

Assignees

• 8 Rivers Capital Llc

Inventors

• Rafati Mohammad
• Allam Rodney John

Classifications

• Y02C20/40

  of CO2 · CPC title

• C01B2203/1241

  Natural gas or methane · CPC title

• C01B2203/1235

  Hydrocarbons · CPC title

• C01B2203/0475

  the impurity being carbon dioxide · CPC title

• C01B2203/046

  Purification by cryogenic separation · CPC title