JP4507458B2 - Method for producing hydrate slurry - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a hydrate slurry.
[0002]
[Prior art]
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 transport medium.
[0003]
Conventionally, the production of such a hydrate slurry and its use in a load-side air conditioning facility or the like have been performed as follows. That is, an aqueous solution containing, for example, tetra n-butylammonium bromide (TBAB) is supplied to the hydrate slurry tank, and the slurry manufacturing operation (heat storage operation) is started. The aqueous solution in the hydrate slurry tank is sent to a slurry production heat exchanger (for example, an evaporator of a refrigerator) by a production pump and cooled by heat exchange to produce a hydrate slurry. This hydrate slurry is stored in a hydrate slurry tank. Further, during the load operation, the hydrate slurry in the hydrate slurry tank is sent to the load-side heat exchanger by the load pump and the cold heat is used to form an aqueous solution, and the aqueous solution is returned to the hydrate slurry tank.
[0004]
By the way, tetra n-butylammonium bromide (TBAB) can produce a first hydrate having a low hydration number and a low production temperature in a low concentration region and a second hydrate having a high hydration number and a high production temperature. (It is known that only the first hydrate is produced in the high concentration region). Of the two types of hydrates, the second hydrate has a larger heat density and a larger amount of cold heat, so it is desirable to use a hydrate slurry containing the second hydrate for the air conditioning load operation.
[0005]
However, if cooling is continuously performed in a slurry production heat exchanger according to a conventional method, supercooling may be released after large supercooling occurs, and in such a case, a hydrate is rapidly formed. In addition, the viscosity increases, the flow resistance increases, the pump power increases, and in the worst case, the heat exchanger may be blocked. In addition, after the first hydrate is first formed during the slurry production operation, the first hydrate is changed to the second hydrate even when the temperature is about 8.0 ° C. or less at which the second hydrate can be formed. Instead, it often happened that after being cooled down to a lower temperature, it changed to the second hydrate, resulting in pump power fluctuations.
[0006]
For this reason, in order to operate stably at the time of manufacture of the hydrate slurry, it is important to generate the second hydrate as soon as possible.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a method capable of promptly producing a second hydrate at the time of producing a hydrate and stably producing a hydrate slurry.
[0008]
(1) The method of producing the hydrate slurry according to the present invention, the guest compound to generate a second hydrate large thermal density large hydration number than the monohydrate or said monohydrate a method of cooling the aqueous solution to produce a clathrate hydrate slurry, a tank for storing the hydrate slurry containing the first dihydrate connected to the load-side heat exchanger slurry manufacturing heat exchangers, to the tank A part of the hydrate slurry stored and the aqueous solution transported from the load side heat exchanger are transported to the slurry production heat exchanger to be cooled, and a part of the hydrate slurry stored in the tank is cooled. It is transported to the load side heat exchanger and uses cold energy .
[0011]
( 2 ) Further, in the above ( 1 ), the flow rate of the load pump that transports a part of the hydrate slurry stored in the tank to the load-side heat exchanger is Qf, and is stored in the tank. A flow rate of a production pump for transporting a part of the hydrate slurry and the aqueous solution returning from the load side heat exchanger to the slurry production heat exchanger is controlled so that Qm> Qf. It is what.
In the present invention, as the guest compound, 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 is used. It is done.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a slurry manufacturing / air conditioning system used for carrying out the method of the present invention. As shown in FIG. 1, a buffer tank 1 for storing a hydrate slurry containing a second hydrate is provided so as to be connected to a slurry production heat exchanger 11 and a load side heat exchanger 21. More specifically, a feed pipe 3 including a production pump 2 is provided between the buffer tank 1 and the slurry production heat exchanger 11, and a return pipe 4 from the slurry production heat exchanger 11 is provided in the buffer tank 1. It is connected to the. Between the buffer tank 1 and the load side heat exchanger 21, a feed pipe 6 having a load pump 5 is provided. A return pipe 7 from the load side heat exchanger 21 is connected to the slurry production heat exchanger from the buffer tank 1. 11 is connected to the feed pipe 3.
[0013]
Cold water cooled by the refrigerator 12 is transported to the slurry production heat exchanger 11 by a cold water pump 13 and used for slurry production.
[0014]
The flow rate Qm of the production pump 2 and the flow rate Qf of the load pump 5 are measured by a flow meter (not shown), and these flow rates are controlled by the controller 31.
[0015]
The slurry manufacturing / air conditioning system is operated as follows. First, an aqueous solution containing, for example, tetra n-butylammonium bromide (TBAB) as a guest compound is placed in the buffer tank 1, and a heat storage operation is performed in advance to store a hydrate slurry containing a second hydrate in the buffer tank 1. deep. Then, a load operation is performed, and a part of the second hydrate slurry of the buffer tank 1 is transported to the load-side heat exchanger 21 by the load pump 5 and the cold heat is used, while the production pump 2 uses the first of the buffer tank 1. A part of the dihydrate slurry and the aqueous solution returning from the load side heat exchanger 21 are transported to the slurry production heat exchanger 11 and cooled. Such a load operation can be performed by controlling the flow rate Qm of the production pump 2 and the flow rate Qf of the load pump 5 by the controller 31 so that Qm> Qf.
[0016]
When such an operation is performed, since the second hydrate slurry and the aqueous solution are mixed and transported to the slurry production heat exchanger 11, the first hydrate is generated in the slurry production heat exchanger 11. The second hydrate slurry is stably produced. The hydrate slurry returning from the slurry production heat exchanger 11 passes through the buffer tank 1 and is then transported from the buffer tank 1 to the load side heat exchanger 21. For this reason, even if the first hydrate is generated at the outlet of the slurry production heat exchanger 11, the first hydrate is mixed with the second hydrate slurry in the buffer tank 1 as a result. Change to Japanese.
[0017]
【The invention's effect】
As described in detail above, according to the present invention, by transferring a part of the hydrate slurry containing the second hydrate of the buffer tank and the aqueous solution returning from the load side heat exchanger to the slurry production heat exchanger, It is possible to stably produce a hydrate slurry containing the second hydrate without causing supercooling in the slurry production heat exchanger and without producing the first hydrate.
[Brief description of the drawings]
FIG. 1 is a block diagram of a slurry manufacturing / air conditioning system used for carrying out the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Buffer tank 2 ... Production pump 3 ... Feed pipe 4 ... Return pipe 5 ... Load pump 6 ... Feed pipe 7 ... Return pipe 11 ... Slurry manufacture heat exchanger 12 ... Refrigerator 13 ... Cold water pump 21 ... Load side heat exchanger

Claims (2)

A method of cooling the aqueous solution of the guest compound hydration number than the monohydrate or said monohydrate to produce a large thermal density is larger second dihydrate producing hydrate slurry, wherein A tank for storing a hydrate slurry containing a second hydrate is connected to a slurry production heat exchanger and a load side heat exchanger, a part of the hydrate slurry stored in the tank and the load side heat exchange. The aqueous solution transported from the vessel is transported to the slurry production heat exchanger and cooled, and a part of the hydrate slurry stored in the tank is transported to the load side heat exchanger to utilize the cold energy. A method for producing a hydrate slurry. Qf is a flow rate of a load pump that transports a part of the hydrate slurry stored in the tank to the load-side heat exchanger, a part of the hydrate slurry stored in the tank and the load-side heat exchange the solution returning from vessel as Qm the flow rate of the production pump transport to the slurry preparation heat exchanger, Qm> method for producing a hydrate slurry according to claim 1, wherein the controller controls so that Qf.

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