JP7450586B2 - Cold energy recovery system and cold energy utilization method - Google Patents

Description

The present invention relates to a technology for utilizing thermal energy, and in particular to a system and method for effectively utilizing cold energy generated when city gas is decompressed.

In recent years, major gas companies have been working on gas pressure difference power generation at governor stations in city gas pipelines. This is a system that recovers the energy wasted when reducing the pressure of city gas and generates electricity.

However, the pressure reduction of city gas is adiabatic expansion, and the reduced pressure city gas is cooled from 0°C to about -30°C, so it was necessary to warm it to 0°C or higher by heating. For this reason, the profits from gas pressure differential power generation are offset by the costs required for heating, making it unviable as a business and hindering the spread of gas pressure differential power generation.

In view of this situation, Patent Document 1 discloses that exhaust gas from an internal combustion engine that drives a generator provided in a governor station is used for heating a gas conduit. Heating cold energy with discarded thermal energy generates new thermal energy, which can reduce costs compared to the case where this is used for heating. However, it is still the case that the generated energies cancel each other out, and it is difficult to say that this is an improvement in energy efficiency.

In addition, Patent Document 2 discloses that the cold heat of adiabatically expanded gas is absorbed by gas hydrate, which has a higher heat storage property than gas, and is used as a heat removal source for heat exchange with a highly fluid refrigerant such as gas. A technology has been disclosed in which the heat source is used as a cold source for air conditioning equipment and the like. If thermal energy is used in this way, it is possible to use cold energy as cold energy, so it is thought that energy efficiency can be improved. However, the configuration in which gas is hydrated and then heat exchanged with the refrigerant increases the number of heat exchanges and requires at least a gas circulation route, a water circulation route, and storage of gas hydrate. There are concerns that the facility will become larger due to the need for additional elements and refrigerant circulation routes.

Japanese Patent Application Publication No. 8-325583 Japanese Patent Application Publication No. 2003-139357

Therefore, an object of the present invention is to provide a cold heat recovery system and a cold heat utilization method that can efficiently utilize cold heat generated by gas depressurization (adiabatic expansion) with relatively simple equipment.

A cold heat recovery system according to the present invention for achieving the above object includes a heat exchanger that includes at least a shell and a tube, and in which adiabatically expanded gas is supplied to the shell, and a liquid or colloid solution having a freezing point of 0° C. or lower. A heat storage material supply section that supplies a fluid heat storage material consisting of the above to the tube, and a heat storage material recovery section that collects the fluid heat storage material cooled by the heat exchanger.

Further, in the cold heat recovery system having the above characteristics, the fluid heat storage material is composed of a mixture of paraffin, a surfactant for emulsifying the paraffin, water, and a solute that lowers the freezing point of the water. It's good to have one. By having such characteristics, even when the temperature of the fluid heat storage material becomes 0° C. or lower due to heat exchange, the fluidity can be maintained, and it becomes possible to pump the material under pressure.

Furthermore, in the cold heat recovery system having the above characteristics, it is desirable that the solute be sodium chloride or calcium chloride. By having such characteristics, it becomes possible to manufacture the fluid heat storage material at low cost.

Further, the method for utilizing cold energy according to the present invention for achieving the above object includes a heat exchanger that includes at least a shell and a tube, and in which adiabatically expanded gas is supplied to the shell, and a liquid or The heat storage system of the cold heat recovery system includes a heat storage material supply section that supplies a fluid heat storage material made of a colloidal solution to the tube, and a heat storage material recovery section that recovers the fluid heat storage material cooled by the heat exchanger. The fluid heat storage material recovered by the material recovery section is supplied to a cooling facility or a cooling box to cool the inside of the cooling facility or the cooling box.

According to the cold heat recovery system and the cold heat utilization method having the above-mentioned characteristics, the cold heat generated by gas depressurization (adiabatic expansion) can be efficiently used with relatively simple equipment.

FIG. 1 is a diagram showing the configuration of a cold heat recovery system according to an embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a cold energy recovery system and a cold energy utilization method of the present invention will be described in detail with reference to the drawings. First, with reference to FIG. 1, the configuration of a cold heat recovery system according to an embodiment will be described. The embodiments described below are only some of the preferred embodiments for carrying out the present invention, and the present invention may be implemented even if a part of the configuration is changed as long as the effects of the invention are achieved. It can be considered as part of

[composition]
The cold heat recovery system 10 according to the present embodiment includes at least a heat exchanger 12, a heat storage material supply section 18, a heat storage material recovery section 20, and a heat storage material flow path 22. The heat exchanger 12 may be of a general tube type, for example, and may have at least a shell 14 and a tube 16. The shell 14 includes a space in which a fluid for heat exchange is retained, and includes a fluid inlet 14a that allows fluid to flow into the space, a fluid outlet 14b that discharges fluid from the space, a tube fluid inlet 14c, and a tube. It has a fluid outlet 14d. The tube 16 is a tubular member that is disposed in the internal space of the shell 14 and connects the tube fluid inlet 14c and the tube fluid outlet 14d.

The heat storage material supply section 18 is an element for storing the fluid heat storage material supplied into the tube 16 from the tube fluid inlet 14c, and specifically, if it is a tank capable of storing the fluid heat storage material, etc. good. Further, the heat storage material recovery unit 20 is an element for recovering the fluid heat storage material that has undergone heat exchange with the gas in the shell 14 by the heat exchanger 12, and specifically, Similar to the section 18, any tank capable of storing a fluid heat storage material may be used. Note that the heat storage material flow path 22 is a flow path that connects the heat storage material supply section 18 and the tube fluid inlet 14c, and the heat storage material recovery section 20 and the tube fluid outlet 14d, respectively.

Note that the fluid heat storage material according to the present embodiment may be a liquid having a freezing point of 0° C. or lower, or a colloidal solution (sol). A fluid heat storage material with such characteristics has no risk of solidification within the tube 16 even in heat exchange with gas at 0°C or lower, and maintains high heat storage performance compared to gas. I can do it.

A specific example of the fluid heat storage material is a mixture of paraffin, a surfactant for emulsifying the paraffin, water, and a solute that lowers the freezing point of water to 0° C. or lower. Here, the solute that lowers the freezing point of water is preferably sodium chloride or calcium chloride, for example. This is because a fluid heat storage material having such a configuration can maintain a viscosity that allows transportation (pressure feeding) with a pump (not shown) in a temperature range of about 0° C. to -40° C. Furthermore, by using sodium chloride or calcium chloride as the solute, it becomes possible to manufacture the fluid heat storage material at low cost.

[Effect]
In the cold heat recovery system 10 having such a configuration, gas (for example, city gas) that has been cooled to 0° C. or lower (for example, -30° C.) by adiabatic expansion or the like is supplied into the shell 14 through the fluid inlet 14a. . On the other hand, the fluid heat storage material supplied from the heat storage material supply section 18 through the heat storage material channel 22 flows into the tube 16 disposed inside the shell 14, and the gas inside the shell 14 and the tube Heat exchange is performed with the fluid heat storage material in the shell 16, and the fluid heat storage material is cooled to 0° C. or lower, and the gas in the shell is heated to 0° C. or higher.

The gas heated to 0° C. or higher is discharged from the fluid outlet 14b and used as gas. On the other hand, the fluid heat storage material cooled to 0° C. or lower is discharged from the tube fluid outlet 14d and flows out to the heat storage material recovery section 20 via the heat storage material channel 22. The fluid heat storage material flowing into the heat storage material recovery section 20 is used as a coolant for cooling the inside of a cooler box, a cooling box for a refrigerator/freezer vehicle, or a cooling facility such as a refrigerated/freezer warehouse. Note that the form of use of the fluid heat storage material as a coolant is not limited. For example, it may be packed in units of size and weight that are easy to handle, or it may be transported as a cold source for a heat exchange device (cooling equipment) via piping or the like.

[effect]
According to the cold heat recovery system 10 and the cold heat utilization method configured as described above, there is no need to generate a heat source for heating gas. Therefore, there is no need for facilities for generating a heat source, and it becomes possible to efficiently utilize the cold energy generated by the reduced pressure (adiabatic expansion) of the gas using relatively simple equipment. Furthermore, the fluid heat storage material cooled using cold energy can be used and sold as a coolant.

10... Cold heat recovery system, 12... Heat exchanger, 14... Shell, 14a... Fluid inlet, 14b... Fluid outlet, 14c... Tube fluid inlet, 14d...... Tube fluid outlet, 16... tube, 18... heat storage material supply section, 20... heat storage material recovery section, 22... heat storage material flow path.

Claims (4)

a heat exchanger comprising at least a shell and a tube, and adiabatically expanded gas is supplied to the shell;
a heat storage material supply unit that supplies a fluid heat storage material made of a liquid or colloidal solution with a freezing point of 0° C. or lower to the tube;
a heat storage material recovery unit that recovers the fluid heat storage material cooled by the heat exchanger for use outside the system ;
A cold heat recovery system characterized by not having a path for returning the fluid heat storage material from the heat storage material recovery section to the heat storage material supply section . The fluid heat storage material is composed of a mixture of paraffin, a surfactant for emulsifying the paraffin, water, and a solute that lowers the freezing point of the water. Cold heat recovery system. 3. The cold heat recovery system according to claim 2, wherein the solute is sodium chloride or calcium chloride. A heat exchanger comprising at least a shell and a tube, and adiabatically expanded gas being supplied to the shell; and a heat storage material supply unit supplying a fluid heat storage material made of a liquid or colloidal solution with a freezing point of 0° C. or lower to the tube. and a heat storage material recovery unit that recovers the fluid heat storage material cooled by the heat exchanger for use outside the system. supplying the material to a cooling facility outside the cold heat recovery system or a cooling box,
A method for utilizing cold energy, characterized in that the inside of the cooling facility or the inside of the cooling box is cooled without being returned to the heat storage material supply section .

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