Method for Production of Blue Ammonia

Patent metadata

Field	Value
Publication number	US-2024208808-A1
Application number	US-202218555519-A
Country	US
Kind code	A1
Filing date	Apr 6, 2022
Priority date	Apr 28, 2021
Publication date	Jun 27, 2024
Grant date	—

Abstract

The present invention provides a method and system for producing blue ammonia, providing for a higher percentage of carbon capture. The method and system of the invention may be used in any ammonia plant.

First claim

1 . A process for producing ammonia comprising the steps of:
a) removing sulphur and other contaminants from a hydrocarbon feed; b) reforming the hydrocarbon stream from step a) and obtaining synthesis gas comprising CO, CO 2 , H 2 , H 2 O and CH 4 ; c) sending the gas from step b) through a shift reaction step reducing the CO content; d) sending the gas from step c) to a CO 2 removal step where it is split in at least 2 streams: a CO 2 rich stream; and a hydrogen rich stream; e) sending the hydrogen rich stream from step d) through:
i) hydrogen purification and nitrogen wash, where H 2 O, CO, CO 2 , CH 4 are removed in an off-gas stream and N 2 is added to obtain a synthesis gas stream comprising N 2 and H 2 ; or
ii) a PSA, resulting in a hydrogen stream containing more than 99.5% hydrogen to which nitrogen is added to obtain a synthesis gas stream comprising N 2 and H 2 and an off-gas stream; or
iii) methanation step, converting the CO and CO 2 together with H 2 into CH 4 and H 2 O, to obtain a synthesis gas stream, N 2 , H 2 and inerts comprising CH 4 ;
f) sending a part of the synthesis gas stream from step e) through an ammonia synthesis section, where it is converted to NH 3 and another part of the synthesis gas stream is sent to the fuel systems, wherein at least part of the off-gas removed in step e) i) and e) ii) or at least part of recovered CH 4 stemming from synthesis gas in step e) iii) are compressed and sent to step a) or b).

2 . The process according to claim 1 , wherein in step d) the gas from step c) is sent to a CO 2 removal step where it is split in at least 3 streams: a CO 2 rich stream, a flash gas and a hydrogen rich stream, wherein the flash gas is compressed together with streams and sent to step a) or b).

3 . The process according to claim 1 , wherein a hydrocarbon fuel, flash gas from step d), off-gas from step e) and part of the synthesis gas streams from step e) are either premixed or fed separately to the fuel systems g).

4 . The process according to claim 1 , comprising an adiabatic pre-reforming step b 0 ) of the hydrocarbon stream from step a), before step b), wherein a synthesis gas comprising CH 4 , CO, CO 2 , H 2 and H 2 O is obtained.

5 . The process according to claim 1 , wherein the amount of air to the air blown secondary reformer is adjusted to obtain a specific ratio of N 2 and H 2 between 1 to 2.5 and 1 to 3.5, in the stream from the methanation reactor.

6 . The process according to claim 5 , wherein the stream obtained from step e) comprises N 2 and H 2 in a ratio of 1 to 3.0.

7 . A system for producing ammonia according to the process in claim 1 , comprising:
a) a desulfurization unit; b) a reforming unit; c) a shift unit d) a CO 2 removal unit; e) a nitrogen washing unit or a pressure swing adsorption unit or a methanation unit, f) an ammonia synthesis section; and g) fuel systems, wherein streams are directed to fuel systems g) and wherein streams are directed to desulfurization unit a) and/or to reforming unit b).

8 . The system for producing ammonia according to claim 7 , wherein the carbon content in the combined flue gases from the fuel systems g) is less than 5% of the combined carbon content in the hydrocarbon feed and the hydrocarbon fuel.

9 . The system according to claim 7 , wherein a further pre-reforming unit b 0 ) is upstream to the reforming unit b).

10 . The system according to claim 7 , wherein the reforming unit b) comprises an autothermal reformer or a tubular reformer followed by an autothermal reformer or a tubular reformer followed by an air blown secondary reformer.

11 . The system according to claim 7 , wherein the shift unit c) comprises a high temperature reactor or a medium temperature reactor or a low temperature reactor or any combination of at least two of these.

12 . The system according to claim 7 , wherein the fuel systems g) comprise tubular reformers, fired heaters, auxiliary boilers and gas turbines.

13 . The system according claim 12 , wherein the fuel systems g) comprise one or more burners.

14 . A method comprising using the CO 2 obtained in step d) of claim 1 for CO 2 storage.

15 . A method comprising using the CO 2 obtained in step d) of claim 1 to produce chemicals.

Assignees

• Topsoe As

Inventors

• Kakoti Ameet
• Dahl Per Juul

Classifications

• C01C1/0405

  from N2 and H2 in presence of a catalyst · CPC title

• C01B2203/146

  At least two purification steps in series · CPC title

• C01B2203/068

  Ammonia synthesis · CPC title

• C01B2203/0485

  the impurity being a sulfur compound · CPC title

• C01B2203/0475

  the impurity being carbon dioxide · CPC title