JP2010025544A - Hydrate slurry production device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrate slurry production device capable of preventing a pump power from increasing and a heat exchanger from being plugged, caused by excessive cooling at the time of generating a hydrate. <P>SOLUTION: The hydrate slurry production device includes the at least two heat exchangers connected in series, and an excessive cooling releasing means provided in a flow passage of an aqueous solution or a hydrate slurry arranged between the upstream heat exchanger and the downstream heat exchanger, in a device for producing the hydrate slurry containing the hydrate, by passing the aqueous solution of a guest compound generating the hydrate at a temperature higher than 0°C, to be cooled by heat exchange with a cooling medium. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hydrate slurry manufacturing apparatus.

  When an aqueous solution containing a guest compound (tetra n-butylammonium salt, tetraiso-amylammonium salt, tetraiso-butylphosphonium salt, various salts such as triiso-amylsulfonium salt) is cooled, a hydrate (liquid system inclusion) Hydrate) is produced. This hydrate can be produced at a temperature of 0 ° C. or higher, and has a large latent heat and can store cold heat having a heat quantity several times that of cold water. Further, this hydrate becomes fine particles and floats in an aqueous solution to form a hydrate slurry having a relatively high fluidity. For this reason, such a hydrate slurry has favorable characteristics as a cold storage material such as an air conditioner or a cold heat transfer medium.

  An apparatus used to produce the hydrate slurry described above is shown in FIG. The heat storage tank 1 stores a hydrate slurry in which a hydrate is dispersed in an aqueous solution. The aqueous solution in the heat storage tank 1 is sent to the hydrate slurry manufacturing heat exchanger 3 by the aqueous solution pump 2. In this heat exchanger 3, the aqueous solution is cooled by the refrigerator 4 and heat-exchanged with the cooling medium circulated by the cooling medium pump 5 to be cooled, and a hydrate slurry containing hydrate is generated. This hydrate slurry is sent to the heat storage tank 1. Further, the hydrate slurry in the heat storage tank 1 is sent to a load by the slurry pump 6, and its cold energy is used, and returns to the heat storage tank 1.

  By the way, for example, when an aqueous solution of tetra n-butylammonium bromide (TBAB) is used, a first hydrate having a hydration number of 26 and a second hydrate having a hydration number of 36 are formed. When the aqueous concentration of TBAB is about 20 wt%, the freezing point of the first hydrate is about 8.2 ° C., and the change temperature from the first hydrate to the second hydrate is about 8.0 ° C. . When the aqueous solution is cooled by the cooling medium in the heat exchanger 3 of FIG. 1, the first hydrate is not generated at the freezing point of the first hydrate, and the first hydrate is subcooled to a temperature several degrees lower than the freezing point. Monohydrate is produced. In addition, even if the temperature of the first hydrate reaches 8.0 ° C., it does not change to the second hydrate, and changes to the second hydrate after being supercooled to a temperature several degrees lower than the change temperature. .

  As described above, since supercooling occurs in hydrate formation, when the supercooling is released after the temperature difference with the cooling medium is reduced and the heat exchange amount is reduced or the large supercooling occurs, A hydrate is formed and viscosity increases, flow resistance increases, pump power increases, and in the worst case, the heat exchanger may be blocked.

  The objective of this invention is providing the hydrate slurry manufacturing apparatus which can prevent the increase in pump power resulting from the supercooling at the time of hydrate production | generation, and the obstruction | occlusion of a heat exchanger.

  The hydrate slurry manufacturing apparatus according to the present invention includes a refrigerator that supplies a cooling medium, and a hydrate containing a hydrate by cooling an aqueous solution of a guest compound that generates a hydrate by heat exchange with the cooling medium. In an apparatus for producing a product slurry, a first heat exchanger for supercooling an aqueous solution to a temperature below the freezing point of the hydrate, a second heat exchanger connected in series with the first heat exchanger, An aqueous solution or hydrate slurry channel disposed between the first heat exchanger and the second heat exchanger, and a supercooling release means provided in the channel; Release means is a cooling unit connected to a small refrigerator, an oscillation unit connected to an ultrasonic oscillator, a low-frequency vibrator having a frequency of several to several hundreds of Hz, a hydrate inlet, a static mixer, a stirring blade, a pump Or it is the low-temperature protrusion which consists of a Beltier element, It is characterized by the above-mentioned.

  In this invention, the said flow path is provided with the pipe line provided between the 1st heat exchanger and the 2nd heat exchanger, and a supercooling cancellation | release means may be provided in the said pipe line. .

  In the present invention, the flow path includes a pipe line provided between the first heat exchanger and the second heat exchanger, and the pipe line includes a bypass pipe line and a flow path switching valve. And the supercooling release means may be provided in the bypass pipeline.

  In the present invention, the flow path includes a conduit for returning a part of the hydrate slurry from the outlet of the second heat exchanger to the upstream side of the inlet of the heat exchanger. May include a shut-off valve and a pump.

  In the present invention, a plate heat exchanger or a shell-and-tube heat exchanger may be used as the first and second heat exchangers.

  In the present invention, as the guest compound, at least one selected from the group consisting of tetra n-butylammonium salt, tetraiso-amylammonium salt, tetraiso-butylphosphonium salt and triiso-amylsulfonium salt is used.

  ADVANTAGE OF THE INVENTION According to this invention, the hydrate slurry manufacturing apparatus which can prevent the increase in pump power resulting from the supercooling at the time of hydrate production | generation, and the obstruction | occlusion of a heat exchanger can be provided.

It is a block diagram which shows the conventional hydrate slurry manufacturing apparatus. It is a block diagram which shows the heat exchanger part of the hydrate slurry manufacturing apparatus which concerns on this invention. It is a block diagram which shows the heat exchanger part of the other hydrate slurry manufacturing apparatus which concerns on this invention. It is a block diagram which shows an example of the supercooling cancellation | release means which concerns on this invention. It is a block diagram which shows the other example of the supercooling cancellation | release means which concerns on this invention. It is a block diagram which shows the other example of the supercooling cancellation | release means which concerns on this invention. It is a block diagram which shows the other example of the supercooling cancellation | release means which concerns on this invention. It is a block diagram which shows the other example of the supercooling cancellation | release means which concerns on this invention. It is a block diagram which shows the other example of the supercooling cancellation | release means which concerns on this invention. It is a block diagram which shows the other example of the supercooling cancellation | release means which concerns on this invention. It is a block diagram which shows the other example of the supercooling cancellation | release means which concerns on this invention.

Hereinafter, the present invention will be described in more detail.
FIG. 2 is a view showing a portion of the heat exchanger according to one embodiment of the present invention, and is installed as the heat exchanger 3 of FIG. As shown in FIG. 2, a first plate heat exchanger 11 and a second plate heat exchanger 12 are connected in series. The aqueous solution of the guest compound from the heat storage tank enters the first plate heat exchanger 11 from the pipe 13 and is cooled, and then enters the second plate heat exchanger 12 through the pipe 14 and is further cooled. During this time, a hydrate is formed in the aqueous solution, and a hydrate slurry is produced. The produced hydrate slurry returns to the heat storage tank through the pipe line 15. On the other hand, the cooling medium from the refrigerator enters the second plate heat exchanger 12 through the pipe line 16 to exchange heat with the hydrate slurry, and enters the first plate heat exchanger 11 through the pipe line 17. It exchanges heat with the aqueous solution and returns to the refrigerator through the pipe 18. And the supercooling cancellation | release means 19 is provided in the pipe line 14 which connects the 1st plate type heat exchanger 11 and the 2nd plate type heat exchanger 12. FIG. The cooling medium may not be sent in series to the first and second heat exchangers, but may be sent in parallel or partially bypassed.

  In FIG. 4, an example of the supercooling cancellation | release means provided in the pipe line 14 is shown. The supercooling release means in FIG. 4 includes a cooling unit 32 connected to the small refrigerator 31, and the cooling unit 32 is inserted into the pipe line 14 from the outside.

  As shown in FIG. 2, the aqueous solution of the guest compound enters the first plate heat exchanger 11 and exchanges heat with the cooling medium from the refrigerator to approximately the freezing point of the first hydrate or the second hydrate. Cool down to change temperature. As shown in FIG. 4, the cooling part 32 provided in the pipe line 14 is cooled in advance by the small refrigerator 31 to a temperature lower than the change temperature to the second hydrate, and the second hydrate adheres to the surface thereof. is doing. When the aqueous solution supercooled to a temperature lower than the freezing point of the first hydrate or the change temperature to the second hydrate comes into contact with the cooling unit 32, the attached hydrate existing on the surface of the cooling unit 32 becomes a generation nucleus. Acts, the supercooling is released, and hydrates are easily formed. Thus, a hydrate slurry is formed through a slight supercooling. Therefore, a hydrate is suddenly generated in the second plate heat exchanger 12 to increase the viscosity, the flow resistance increases, the pump power increases, and the second plate heat exchanger 12 Occlusion is avoided.

  FIG. 3 is a view showing a portion of a heat exchanger according to another embodiment of the present invention. FIG. 3 shows a first shell-and-tube heat exchanger 21 and a second shell-and-tube heat exchanger instead of the first plate-type heat exchanger 11 and the second plate-type heat exchanger 12 in FIG. The configuration is the same as that shown in FIG. 2 except that the exchanger 22 is used. In this case, the same effect as described above can be obtained.

  The supercooling release means in the present invention is not limited to the cooling unit of the small refrigerator shown in FIG. 4, and other supercooling release means shown in FIGS.

  The supercooling release means in FIG. 5 includes an oscillating unit 34 connected to an ultrasonic oscillator 33, and the oscillating unit 34 is inserted into the pipe line 14 from the outside. When the aqueous solution supercooled to a temperature lower than the freezing point of the first hydrate or the change temperature to the second hydrate contacts the oscillating unit 34, the supercooling is released by vibration and a hydrate is easily generated. . Further, it may be a low frequency vibrator of several to several hundreds of Hz, not ultrasonic vibration.

  The supercooling release means in FIG. 6 includes an injection port 37 in which hydrate is injected from the hydrate slurry container 35 into the conduit 14 by the pump 36. When the aqueous solution supercooled to a temperature lower than the freezing point of the first hydrate or the change temperature to the second hydrate comes into contact with the hydrate injected from the inlet 37, the injected hydrate is formed. Hydrates easily form as nuclei. In this case, the hydrate injected from the injection port 37 is preferably a second hydrate.

  7 comprises a static mixer 38 having a mechanism such as a torsion plate for inverting and mixing the fluid provided in the pipe 14. The aqueous solution supercooled to a temperature lower than the freezing point of the first hydrate or the change temperature to the second hydrate is stirred by the static mixer 38 to release the supercooling, and a hydrate is easily formed.

  The supercooling release means of FIG. 8 is a freezing point or second hydrate of the first hydrate comprising a stirring blade 40 that is housed in a container inserted in the middle of the conduit 14 and is rotated by a motor 39. The aqueous solution supercooled to a temperature lower than the change temperature to is stirred by the stirring blade 40, the supercooling is released, and a hydrate is easily generated.

  As the supercooling release means, a low-temperature protrusion made of a Peltier element or the like may be inserted into the conduit. Similar to the cooling part of the small refrigerator shown in FIG. 4, such a low-temperature protrusion is cooled in advance to a temperature lower than the change temperature to the second hydrate, and the second hydrate adheres to the surface. ing. When an aqueous solution supercooled to a temperature lower than the freezing point of the first hydrate or the change temperature to the second hydrate contacts the low temperature protrusion, the attached hydrate present on the surface of the low temperature protrusion acts as a nucleus. The supercooling is released and a hydrate is easily formed.

  The supercooling release means in FIG. 9 is a pump in which an impeller rotates in a pump casing provided in the middle of the pipeline 14. The aqueous solution supercooled to a temperature lower than the freezing point of the first hydrate or the change temperature to the second hydrate is stirred by the pump 50 to release the supercooling, and a hydrate is easily formed. In this case, the aqueous solution pump 2 of FIG. 1 may be installed between the first heat exchanger and the second heat exchanger.

  FIG. 10 also shows a return pipe 60, a valve 61 and a pump for returning a part of the hydrate slurry from the outlet of the second heat exchanger 12 to the pipe line 14 between the first and second heat exchangers. 62, and a part of the hydrate slurry at the outlet of the second heat exchanger 12 is taken out and mixed with the supercooled aqueous solution at the outlet of the first heat exchanger 11 to release the supercooling.

  In addition, the installation position of the supercooling cancellation | release means in this invention will not be specifically limited if it is a position which can produce | generate the aqueous solution or hydrate slurry containing the at least 2 heat exchanger connected in series. For example, the supercooling release means may be provided at the inlet of the second plate heat exchanger 12 shown in FIG. 2 or the inlet of the second shell and tube heat exchanger 22 shown in FIG. Moreover, you may provide a supercooling cancellation | release means in the pipe chamber shown by A of the 1st shell and tube type heat exchanger 21 shown in FIG. Further, as shown in FIG. 11, a bypass pipe 41 is provided in the pipe 14 between the first heat exchanger and the second heat exchanger, and the flow path is switched to the pipe 14 and the bypass pipe 41, respectively. The valves 42 and 43 may be provided, and the bypass conduit 41 may be provided with a supercooling release means such as the cooling unit 32 of the small refrigerator. Further, the supercooling release means is not limited to one place, and may be provided at a plurality of places. Moreover, you may use together several types of different supercooling cancellation | release means.

DESCRIPTION OF SYMBOLS 1 ... Heat storage tank 2 ... Aqueous solution pump 3 ... Heat exchanger for hydrate slurry manufacture 4 ... Refrigerator 5 ... Coolant pump 6 ... Slurry pump 7 ... Load 11 ... First plate type heat exchanger 12 ... Second Plate type heat exchanger 13, 14, 15, 16, 17, 18 ... Pipe line 19 ... Supercooling release means 21 ... First shell-and-tube heat exchanger 22 ... Second shell-and-tube heat exchanger 31 ... Small refrigerator 32 ... Cooling part 33 ... Ultrasonic oscillator 34 ... Oscillator 35 ... Hydrate slurry container 36 ... Pump 37 ... Inlet 38 ... Static mixer 39 ... Motor 40 ... Agitating blade 41 ... Bypass pipes 42, 43 ... Flow path switching valve 50 ... Pump 60 ... Return pipe 61 ... Valve 62 ... Pump

Claims (6)

  In a refrigerator for supplying a cooling medium and an apparatus for producing a hydrate slurry containing a hydrate by cooling an aqueous solution of a guest compound that forms a hydrate by heat exchange with the cooling medium, A first heat exchanger that supercools the aqueous solution to a temperature below the freezing point; a second heat exchanger connected in series with the first heat exchanger; and the first heat exchanger and the second heat exchange. An aqueous solution or hydrate slurry channel disposed between the unit and a supercooling release unit provided in the channel, wherein the supercooling release unit is connected to a small refrigerator. Oscillating unit connected to an ultrasonic oscillator, a low-frequency projection consisting of a low-frequency vibrator having a frequency of several to several hundreds of Hz, a hydrate inlet, a static mixer, a stirring blade, a pump, or a Bertier element Hydrate slurry production equipment.   The said flow path is provided with the pipe line provided between the 1st heat exchanger and the 2nd heat exchanger, The said supercooling cancellation | release means was provided in the said pipe line, It is characterized by the above-mentioned. The hydrate slurry manufacturing apparatus according to Item 1.   The flow path includes a pipe line provided between the first heat exchanger and the second heat exchanger, the pipe line is provided with a bypass pipe line and a flow path switching valve, and the bypass pipe The apparatus for producing a hydrate slurry according to claim 1, wherein the supercooling release means is provided in a path.   The flow path includes a conduit for returning a part of the hydrate slurry from the outlet of the second heat exchanger to the upstream side of the inlet of the heat exchanger, and the conduit includes a shutoff valve and The apparatus for producing a hydrate slurry according to claim 1, further comprising a pump.   The hydrate slurry manufacturing apparatus according to any one of claims 1 to 4, wherein the first and second heat exchangers are plate heat exchangers or shell and tube heat exchangers.   The guest compound is at least one selected from the group consisting of a tetra n-butylammonium salt, a tetraiso-amylammonium salt, a tetraiso-butylphosphonium salt, and a triiso-amylsulfonium salt. Item 6. The hydrate slurry production apparatus according to any one of Items 1 to 5.

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