Chiller, air separation system, and related methods

12038,230

17/036439

September 29, 2020

A chiller can be configured as a chiller for a gasification system or other type of system or plant. In some embodiments, the chiller can be configured to utilize a single heat source, such as low grade waste heat in the form of hot water, and/or low pressure steam to drive one or more absorption-based chillers to cool inlet air to one or more adsorbers of a pre-purification unit (PPU). In the event of the detection of an undesired impurity spike (e.g. carbon dioxide spike, etc.) an additional amount of heat source can be withdrawn from the gasification system to increase the level of cooling the absorption chiller can provide to improve the removal of impurities. An automated control loop can be utilized in some embodiments. The control loop can be configured to check for an impurity concentration and adjust operations accordingly.

Air Products and Chemicals, Inc. (Allentown, PA, US)

Air Products and Chemicals, Inc. (Allentown, PA, US)

1. An absorption based chilling system for an air separation unit (ASU) of a plant, the absorption based chilling system comprising: at least one absorption chiller positioned to receive at least one process stream from a gasification section of the plant so heat from the at least one process stream is fed to at least one generator of the at least one absorption chiller, the at least one absorption chiller being positionable to: (i) cool air at a first pressure from a compression system of the ASU for feeding the cooled air to a pre-purification unit (PPU) for purification of the air to form a purified air flow for feeding the purified air flow to a cold box of the ASU, (ii) cool the purified air flow from the PPU before the purified air flow is fed to the cold box, and/or (iii) the cool air at a second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure, the first pressure being higher than the second pressure; wherein the absorption based chilling system comprises one or more sensors and wherein the one or more sensors is configured to detect an impurity concentration of the air and the at least one absorption chiller includes a primary absorption chiller and a secondary absorption chiller, and wherein one of: the absorption based chilling system is configured so that a first portion of the air at the first pressure from the compression system is fed to the primary absorption chiller for chilling and a second portion of the air at the first pressure from the compression system is fed to the secondary absorption chiller for chilling in response to the impurity concentration being at or above a pre-selected threshold, and the absorption based chilling system is configured so that (i) a first portion of a cooling medium to be fed to a direct contact cooler for cooling the air at the first pressure from the compression system, is fed to the primary absorption chiller, the primary absorption chiller to cool the first portion of the cooling medium to a pre-selected direct contact cooler chilling medium inlet temperature and (ii) a second portion of the cooling medium to be fed to the direct contact cooler for cooling the air at the first pressure, is fed to the secondary absorption chiller, the secondary absorption chiller to cool the second portion of the cooling medium to the pre-selected direct contact cooler chilling medium inlet temperature in response to the impurity concentration being at or above the pre-selected threshold.

2. The absorption based chilling system of claim 1 , wherein the at least one absorption chiller is positionable to: (i) cool the air at the first pressure from the compression system of the ASU for feeding the cooled air to the PPU for purification of the air to form the purified air flow for feeding the purified air flow to the cold box of the ASU, (ii) cool the purified air flow from the PPU before the purified air flow is fed to the cold box, and (iii) cool the air at the second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure.

3. The absorption based chilling system of claim 1 , wherein the at least one absorption chiller is positionable to: (i) cool the air at the first pressure from the compression system of the ASU for feeding the cooled air to the PPU for purification of the air to form the purified air flow for feeding the purified air flow to the cold box of the ASU, and (ii) cool the purified air flow from the PPU before the purified air flow is fed to the cold box.

4. The absorption based chilling system of claim 1 , wherein the at least one absorption chiller is positionable to: (i) cool the air at the first pressure from the compression system of the ASU for feeding the cooled air to the PPU for purification of the air to form the purified air flow for feeding the purified air flow to the cold box of the ASU, and (iii) cool the air at the second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure.

5. The absorption based chilling system of claim 1 , wherein the at least one absorption chiller is positionable to: (ii) cool the purified air flow from the PPU before the purified air flow is fed to the cold box, and (iii) cool of the air at the second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure.

6. The absorption based chilling system of claim 1 , wherein at least one evaporator of the at least one absorption chiller cools the air at the first pressure received from the compression system of the ASU for feeding the cooled air to the PPU, cools the purified air flow from the PPU before the purified air flow is fed to the cold box, and/or cools the air at the second pressure from the compression system.

7. The absorption based chilling system of claim 1 , wherein the direct contact cooler connected to the at least one absorption chiller to receive the cooling medium from the absorption chiller for cooling the air at the first pressure.

8. The absorption based chilling system of claim 7 , wherein the cooling medium is comprised of water or glycol and the PPU includes at least one radial adsorber.

9. The absorption based chilling system of claim 8 , wherein the cooling medium comprises water and the absorption based chilling system also comprises a cooling tower positioned between the cold box and the at least one absorption chiller to cool the cooling medium before the cooling medium is fed to the at last one absorption chiller, the cooling tower being positioned to receive a flow of cooling fluid from the cold box to cool the cooling medium before the cooling medium is fed to the at least one absorption chiller.

10. The absorption based chilling system of claim 1 , wherein the PPU includes radial adsorbers.

11. A plant comprising: an air separation unit (ASU) having the absorption based chilling system of claim 1 ; and the gasification section.

12. The plant of claim 11 , wherein the ASU has the compression system, the cold box, and the PPU and at least one knockout drum positioned between the absorption based chilling system and the cold box.

13. The plant of claim 11 , wherein the at least one process stream from the gasification section of the plant also heats a heater for heating regeneration fluid feedable to at least one adsorber of the PPU in an off-state position during operation of the plant for heating a regeneration fluid passed through the at least one adsorber for regeneration of adsorbent material within the at least one adsorber.

14. A method of cooling air in an air separation unit (ASU) of a plant, the plant also having a gasification section, the method comprising: positioning at least one absorption chiller in the ASU to receive at least one process stream from the gasification section so heat from the at least one process stream from the gasification section is feedable to at least one generator of the at least one absorption chiller; providing cooling via the at least one absorption chiller to facilitate: (i) cooling air at a first pressure from a compression system of the ASU for feeding the cooled air to a pre-purification unit (PPU) for purification of the air to form a purified air flow for feeding the purified air flow to a cold box of the ASU, (ii) cooling the purified air flow from the PPU before the purified air flow is fed to the cold box, and/or (iii) cooling the air at a second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure, the first pressure being higher than the second pressure; wherein the at least one absorption chiller includes a primary absorption chiller and a secondary absorption chiller, the method also comprising: one of: in response to one or more sensors determining that an impurity concentration level is at or above a pre-selected threshold, adjusting operations of the at least one absorption chiller so that a first portion of the air at the first pressure from the compression system is fed to the primary absorption chiller and a second portion of the air at the first pressure from the compression system is fed to the secondary absorption chiller, and in response to one or more sensors determining that the impurity concentration level is at or above the pre-selected threshold, adjusting operations of the at least one absorption chiller so that (i) a first portion of a cooling medium to be fed to a direct contact cooler, the direct contact cooler for cooling the air at the first pressure from the compression system, is fed to the primary absorption chiller, the primary absorption chiller to cool the first portion of the cooling medium to a pre-selected direct contact cooler chilling medium inlet temperature and (ii) a second portion of the cooling medium to be fed to the direct contact cooler for cooling the air at the first pressure from the compression system, is fed to the secondary absorption chiller, the secondary absorption chiller to cool the second portion of the cooling medium to the pre-selected direct contact cooler chilling medium inlet temperature.

15. The method of claim 14 , wherein the providing the cooling via the at least one absorption chiller includes: (i) the cooling of the air at the first pressure from the compression system of the ASU for feeding the cooled air to the PPU for purification of the air to form the purified air flow for feeding the purified air flow to the cold box of the ASU, (ii) the cooling of the purified air flow from the PPU before the purified air flow is fed to the cold box, and (iii) the cooling of the air at the second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure.

16. The method of claim 14 , wherein the providing the cooling via the at least one absorption chiller includes: (i) the cooling of the air at the first pressure from the compression system of the ASU for feeding the cooled air to the PPU for purification of the air to form the purified air flow for feeding the purified air flow to the cold box of the ASU, and (ii) the cooling of the purified air flow from the PPU before the purified air flow is fed to the cold box.

17. The method of claim 14 , wherein the providing the cooling via the at least one absorption chiller includes: (i) the cooling of the air at the first pressure from the compression system of the ASU for feeding the cooled air to the PPU for purification of the air to form the purified air flow for feeding the purified air flow to the cold box of the ASU, and (iii) the cooling of the air at the second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure.

18. The method of claim 14 , wherein the providing the cooling via the at least one absorption chiller includes: (ii) the cooling of the purified air flow from the PPU before the purified air flow is fed to the cold box, and (iii) the cooling of the air at the second pressure from the compression system of the ASU for feeding the cooled air at the second pressure to the compression system to undergo further compression to the first pressure.

19. The method of claim 14 , wherein at least one evaporator of the at least one absorption chiller cools the air at the first pressure received from the compression system of the ASU for feeding the cooled air to the PPU, cools the purified air flow from the PPU before the purified air flow is fed to the cold box, and/or cools the air at the second pressure from the compression system.

20. The method of claim 14 , comprising: utilizing the at least one process stream from the gasification section to heat regeneration fluid to feed the heated regeneration fluid to an adsorber of the PPU that is in an off-state position for regeneration of adsorbent material within the adsorber of the PPU that is in the off-state position.

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