Apparatus for producing hydrate slurry

• US 20050163681A1
• Filed: 03/14/2003
• Published: 07/28/2005
• Est. Priority Date: 05/31/2002
• Status: Active Grant

• Current Assignee: JFE Engineering Corporation (JFE Holdings Incorporated)
• Original Assignee: JFE Engineering Corporation (JFE Holdings Incorporated)
• Inventors: Takao, Shingo, Furumoto, Naoyuki, Ogoshi, Hidemasa, Matsumoto, Shinegori
• Granted Patent: US 7,541,009 B2
• Time in Patent Office: Days
• US Class Current: 422/198
• CPC Class Codes: F24F 5/0017 using cold storage bodies, e.g. ice
• CPC Class Codes: F25B 2315/003 Hydrates for sorption cycles
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: F25B 5/02 arranged in parallel
• CPC Class Codes: F25D 17/02 for circulating liquids, e.g. brine
• CPC Class Codes: F28F 13/125 by stirring
• CPC Class Codes: Y02E 60/14 Thermal energy storage

Abstract

An apparatus produces hydrate slurry, which is a mixture of aqueous solution and hydrate, by cooling aqueous solution containing a guest compound, which generates the hydrate at temperature higher than 0° C., by using a cooling medium. The apparatus includes a first heat exchanger for supercooling the aqueous solution while holding the aqueous solution in a liquid state and in a second heat exchanger, which is provided on the downstream side of the first heat exchanger for cooling hydrate slurry.

Claims

1. An apparatus for generating hydrate slurry, wherein the hydrate slurry is a mixture of aqueous solution and a hydrate, the hydrate slurry is generated by cooling aqueous solution containing a guest compound by using a cooling medium, and the guest compound generates a hydrate at temperature of more than 0°

C.,

the apparatus comprising a first heat exchanger and a second heat exchanger, the first heat exchanger supercooling the aqueous solution while holding the aqueous solution in a liquid state and the second heat exchanger cooling the hydrate slurry, the second heat exchanger being provided on the downstream side of said first heat exchanger.

2. The apparatus according to claim 1, characterized in that canceling means for canceling the supercooling of the aqueous solution is provided between said first heat exchanger and said second heat exchanger.

3. The apparatus according to claim 1 or 2, characterized in that a plurality of said second heat exchangers are provided so as to be switchable.

4. The apparatus according to claim 2, characterized in that the canceling means comprises means for introducing the hydrate slurry into the supercooled aqueous solution.

5. The apparatus according to claim 4, characterized in that the aqueous solution supercooled by the first heat exchanger has a supercooling degree of 0.7°

C. or more.

6. The apparatus according to claim 4, characterized in that the hydrate slurry introduced into aqueous solution supercooled by the first heat exchanger is in an amount of 1 vol % or more of the total amount of the aqueous solution.

7. The apparatus according to claim 4, characterized in that the hydrate slurry introduced into aqueous solution supercooled by said first heat exchanger is in an amount of 1.8 vol % or more of the total amount of the aqueous solution.

8. The apparatus according to claim 4, characterized in that the aqueous solution has a Reynolds number of 4500 or more.

9. The apparatus according to claim 4, characterized in that the hydrate slurry introduced into supercooled aqueous solution is generated by the second heat exchanger.

10. The apparatus according to claim 4, characterized in that the hydrate slurry introduced into supercooled aqueous solution is accommodated in a thermal storage tank for hydrate slurry.

11. The apparatus according to claim 2, characterized in that the means for canceling supercooling is a cooling portion of a small refrigerating machine, a low-temperature protrusion, an oscillating portion of an ultrasonic oscillator, a low-frequency oscillator, a static mixer, a mixing blade, or a pump.

12. The apparatus according to claim 3, characterized in that when adhesion of hydrate is detected in a second heat exchanger which is being used to generate hydrate slurry, of said plurality of second heat exchangers, operation is performed such that the production of hydrate slurry is stopped in the second heat exchanger and the second heat exchanger is switched over to another one to continue the production of hydrate slurry, and the hydrate slurry in the second heat exchanger in which the production of hydrate slurry is stopped is melted.

13. The apparatus according to claim 3, characterized in that said plurality of second heat exchangers are switched over successively at the fixed time interval to perform melting operation.

14. The apparatus according to claim 1, characterized in that said guest compound is at least one selected from the group consisting of tetra-n-butyl ammonium salt, tetra-iso-amyl ammonium salt, tetra-n-butyl phosphonium salt, and tetra-iso-amyl sulfonium salt.

15. In an apparatus for generating hydrate slurry containing a hydrate of guest compound by cooling aqueous solution containing a guest compound which generates a hydrate at temperature of higher than 0°

C., the apparatus comprising;

a refrigerating machine having a plurality of evaporators provided so as to be switchable;

a circulation system for the aqueous solution of the guest compound, so as to cool the aqueous solution of the guest compound by each of said evaporators;

controlling means for stopping cooling the aqueous solution of the guest compound in one evaporator when the circulation system for the aqueous solution of the guest compound in the evaporator is blocked, and the circulation system for starting cooling the aqueous solution of the guest compound in another evaporator; and

means for supplying a high-temperature refrigerant in said refrigerating machine to an evaporator in which cooling the aqueous solution of the guest compound stops.

16. The apparatus according to claim 15, characterized by further comprising means for detecting that the circulation system arranged in said evaporator is blocked by hydrate.

17. The apparatus according to claim 16, characterized in that said detecting means is at least one of a flowmeter and a thermometer provided on an outlet pipe from the evaporator of said circulation system and a differential pressure gage provided across an inlet pipe to the evaporator of said circulation system and the outlet pipe from the evaporator.

18. The apparatus according to claim 15, characterized in that said refrigerating machine is an absorption refrigerating machine and has means for supplying refrigerant gas generated in a generator to the evaporator in which cooling the aqueous solution of the guest compound stops.

19. The apparatus according to claim 15, characterized in that said refrigerating machine is a compression refrigerating machine and has means for supplying refrigerant gas generated in a compressor to the evaporator in which cooling aqueous solution of the guest compound stops.

20. The apparatus according to claim 15, characterized in that said refrigerating machine is a compression refrigerating machine and has means for supplying refrigerant liquid generated in a condenser to the evaporator in which cooling the aqueous solution of the guest compound stops.

21. The apparatus according to any one of claims 15 to 20, characterized in that the aqueous solution of the guest compound is supercooled in the circulation system arranged in said evaporator, and canceling means for canceling the supercooled state of the supercooled aqueous solution to generate the hydrate slurry is located onto an outlet pipe of the circulation system for the aqueous solution of the guest compound from said evaporator.

22. The apparatus according to claim 21, characterized in that said canceling means is a cooling portion of a small refrigerating machine, a low-temperature protrusion, an oscillating portion of an ultrasonic oscillator, a low-frequency oscillator, hydrate slurry injecting means, a static mixer, a mixing blade, or a pump.

23. The apparatus according to any one of claims 15 to 20, characterized in that said guest compound is at least one selected from the group consisting of tetra-n-butyl ammonium salt, tetra-iso-amyl ammonium salt, tetra-iso-butyl phosphonium salt, and tri-iso-amyl sulfonium salt.