Apparatus and system for swing adsorption processes related thereto

• US 10,124,286 B2
• Filed: 08/10/2016
• Issued: 11/13/2018
• Est. Priority Date: 09/02/2015
• Status: Active Grant

• Current Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Original Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Inventors: McMahon, Patrick D. J., Johnson, Robert A., Ramkumar, Shwetha, Oelfke, Russell H., Thomas, Eugene R., Nagavarapu, Ananda K., Barnes, William
• Primary Examiner(s): Lawrence, Jr., Frank M
• Application Number:
  US15/233,623
• Publication Number:
  US 20170056813A1
• Time in Patent Office: 825 Days
• Field of Search: 95 96- 99, 95104-106, 95117, 95122-124, 95139, 96108, 96121, 96126-128, 96143, 96144, 62618
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2253/116 Molecular sieves other than zeolites
• CPC Class Codes: B01D 2256/24 Hydrocarbons
• CPC Class Codes: B01D 2256/245 Methane
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/40 Nitrogen compounds
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 2259/40013 Pressurization
• CPC Class Codes: B01D 2259/40043 Purging
• CPC Class Codes: B01D 2259/40054 treated before its reuse
• CPC Class Codes: B01D 2259/40086 by using a purge gas B01D2259/4009 takes precedence
• CPC Class Codes: B01D 2259/4009 using hot gas
• CPC Class Codes: B01D 2259/4062 using six beds
• CPC Class Codes: B01D 2259/416 involving cryogenic temperature treatment
• CPC Class Codes: B01D 53/0407 Constructional details of adsorbing systems
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01D 53/0473 Rapid pressure swing adsorption
• CPC Class Codes: C10L 2290/543 Distillation, fractionation or rectification for separating fractions, components or impurities during preparation or upgrading of a fuel
• CPC Class Codes: C10L 3/104 : Carbon dioxide
• CPC Class Codes: C10L 3/106 : of water
• CPC Class Codes: F25J 2200/02 : in a single pressure main column system
• CPC Class Codes: F25J 2200/40 : Features relating to the provision of boil-up in the bottom of a column
• CPC Class Codes: F25J 2200/70 : Refluxing the column with a condensed part of the feed stream, i.e. fractionator top is stripped or self-rectified
• CPC Class Codes: F25J 2205/04 : in the feed line, i.e. upstream of the fractionation step
• CPC Class Codes: F25J 2205/64 : by pressure-swing adsorption [PSA] at the hot end
• CPC Class Codes: F25J 2205/66 : Regenerating the adsorption vessel, e.g. kind of reactivation gas
• CPC Class Codes: F25J 2220/66 : Separating acid gases, e.g. CO2, SO2, H2S or RSH
• CPC Class Codes: F25J 2220/68 : Separating water or hydrates
• CPC Class Codes: F25J 2230/32 : Compression of the product stream
• CPC Class Codes: F25J 2230/60 : the fluid being hydrocarbons or a mixture of hydrocarbons
• CPC Class Codes: F25J 2240/02 : Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
• CPC Class Codes: F25J 3/0209 : Natural gas or substitute natural gas
• CPC Class Codes: F25J 3/0233 : separation of CnHm with 1 carbon atom or more
• CPC Class Codes: F25J 3/0238 : separation of CnHm with 2 carbon atoms or more
• CPC Class Codes: F25J 3/061 : Natural gas or substitute natural gas
• CPC Class Codes: Y02C 20/40 : of CO2

Abstract

Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve passing streams through adsorbent bed units to remove contaminants, such as water, from the stream. As part of the process, the adsorbent bed unit is purged with a purge stream that is provided from the overhead of the demethanizer. The configuration integrates a PPSA dehydration system with a cryogenic recovery system.

Claims

1. A cyclical swing adsorption process for removing contaminants from a gaseous feed stream, the process comprising:

a) performing one or more adsorption steps, wherein each of the adsorption steps comprises passing a gaseous feed stream at a feed pressure and feed temperature through an adsorbent bed unit to remove one or more contaminants from the gaseous feed stream and to form a product stream that is passed to a cryogenic recovery system including a demethanizer;

b) passing the product stream through a gas/gas exchanger;

c) passing at least a portion of the product stream to the demethanizer to separate the at least a portion of the product stream into a final product stream and a demethanizer overhead stream;

d) passing at least a portion of the demethanizer overhead stream through the gas/gas exchanger to lower the temperature of the product stream;

e) performing one or more depressurization steps, wherein the pressure of the adsorbent bed unit is reduced by a predetermined amount with each successive depressurization step;

f) performing one or more purge steps, wherein each of the purge steps comprises passing a purge stream through the adsorbent bed unit in a counter flow direction relative to the flow of the gaseous feed stream to form a purge product stream, wherein the purge stream comprises at least a portion of a demethanizer overhead stream from the demethanizer;

g) performing one or more re-pressurization steps, wherein the pressure within the adsorbent bed unit is increased with each re-pressurization step by a predetermined amount with each successive re-pressurization step; and

repeating the steps a) and e) to g) for at least one additional cycle.

2. The cyclical swing adsorption process of claim 1, wherein the purge stream comprises at least 20 volume % of the demethanizer overhead stream.

3. The cyclical swing adsorption process of claim 1, wherein the purge stream comprises at least 50 volume % of the demethanizer overhead stream.

4. The cyclical swing adsorption process of claim 1, wherein the purge stream comprises at least 95 volume % of the demethanizer overhead stream.

5. The cyclical swing adsorption process of claim 1, wherein the purge stream is at a purge temperature within a range between 10°

F. below the feed temperature (5.6°

C. below the feed temperature) and 350°

F. above the feed temperature (194°

C. above the feed temperature).

6. The cyclical swing adsorption process of claim 1, wherein the purge stream is at a purge temperature within a range from 10°

F. below the feed temperature (5.6°

C. below the feed temperature) and 25°

F. above the feed temperature (13.9°

C. above the feed temperature).

7. The cyclical swing adsorption process of claim 1, wherein the cycle duration is greater than 1 second and less than 600 seconds.

8. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream is a hydrocarbon containing stream having greater than one volume percent hydrocarbons based on the total volume of the feed stream.

9. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream comprises hydrocarbons and H₂O, wherein the H₂O is one of the one or more contaminants and the gaseous feed stream comprises H₂O in the range of two parts per million molar to saturation levels in the gaseous feed stream.

10. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream comprises hydrocarbons and H₂O, wherein the H₂O is one of the one or more contaminants and the gaseous feed stream comprises H₂O in the range of 50 parts per million molar to 1,500 parts per million molar.

11. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream comprises hydrocarbons and CO₂, wherein the CO₂ is one of the one or more contaminants and the gaseous feed stream comprises CO₂ in the range between 0 molar percent and 5 molar percent of the total volume of the gaseous feed stream.

12. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream comprises hydrocarbons and the one or more contaminants comprise CO₂, wherein the CO₂ in the gaseous feed stream is less than the quantity of one minus the molar fraction of heavy hydrocarbons in the gaseous feed stream times a sales gas CO₂ maximum concentration specification.

13. The cyclical swing adsorption process of claim 1, wherein the feed pressure is in the range between 400 pounds per square inch absolute (psia) and 1,400 psia.

14. The cyclical swing adsorption process of claim 1, wherein the cycle duration is greater than 2 seconds and less than 300 seconds.

15. The cyclical swing adsorption process of claim 1, wherein water content in the product stream is in the range between 0.0 ppm and 5.0 ppm.

16. The cyclical swing adsorption process of claim 1, wherein the cryogenic recovery system is a cryogenic natural gas liquids recovery system.

17. The cyclical swing adsorption process of claim 1, wherein the cryogenic recovery system is a cryogenic controlled freeze zone recovery system.

18. The cyclical swing adsorption process of claim 1, wherein at least one of the purge steps produces a purge output stream which is compressed to form a sales gas stream, and the pressure of the purge output stream is within a range of 10% of the pressure of the sales gas stream.

19. The cyclical swing adsorption process of claim 1, wherein the adsorbent bed unit comprises an adsorbent material of Zeolite 3A, Zeolite 4A or Zeolite 5A.

20. A system for removing contaminants from a gaseous feed stream, the system comprising:

one or more adsorbent bed units, wherein each of the one or more adsorbent bed units is configured to separate contaminants from a gaseous feed stream and to output a product stream, wherein the gaseous feed stream is provided at a feed temperature;

a cryogenic recovery system configured to receive the product stream and pass at least a portion of the product stream to a demethanizer to separate the at least a portion of the product stream into a final product stream and a demethanizer overhead stream;

a gas/gas exchanger unit configured to receive the product stream from the adsorbent bed unit and to lower the temperature of the product stream by heat exchange with the at least a portion of the demethanizer overhead stream to produce an exchanger output stream; and

wherein a purge stream is passed through the each of the one or more adsorbent bed units and comprises at least a portion of the demethanizer overhead stream.

21. The system of claim 20, further comprising:

a glycol contactor unit configured to receive an input stream and to remove at least a portion of the water from the input stream to form an output stream from the glycol contactor unit; and

a filter unit configured to receive the output stream from the glycol contactor unit and to conduct away particulates and liquid droplets and to provide the feed stream to the one or more adsorbent bed units.

22. The system of claim 20, wherein the gaseous feed stream water content is below saturation levels.

23. The system of claim 20, further comprising a subcooler unit configured to receive a portion of the exchanger output stream from the gas/gas exchanger unit and to adjust the temperature of the portion of the exchanger output stream to the desired temperature for the demethanizer by heat exchange with the at least portion of the demethanizer overhead stream.

24. The system of claim 20, further comprising a compressor configured to receive the demethanizer overhead stream from the gas/gas exchanger unit;

increase the pressure of the demethanizer overhead stream into a compressed demethanizer overhead stream; and

provide the compressed demethanizer overhead stream to a regeneration adsorbent bed unit as the purge stream.

25. The system of claim 20, wherein the cryogenic recovery system is a cryogenic natural gas liquids recovery system.

26. The system of claim 20, wherein the cryogenic recovery system is a cryogenic controlled freeze zone recovery system.