JPS62159895A - Device for preventing freezing of stratum for low-temperature storage tank - Google Patents

Abstract

PURPOSE:To reduce an operating cost by operating a heat pump with a low temp. source such as seawater, etc. and the coolness of a low temp. carrying liquid as heat sources. CONSTITUTION:Two hydrogenated metals having different equilibrium characteristics to pressure and temperature are filled into reaction containers 21-24 respectively. Heat from a low heat source is applied to one reaction container which is filled with the hydrogenated metal of the same temp. and a high equilibrium pressure, to generate a hydrogen gas by the decomposition reaction on the hydrogenated metal. Or, by providing a first heat exchanger 25 by means of which a generated heat accompanying the forming reaction of the hydrogenated metal is absorbed by an extremely low heat of a low temp. carrying liquid in a low temp. storage tank 12, a high temp. due to heat generating reaction between a hydrogen gas and the hydrogenated metal from one reaction container is fed to a heating medium in the other reaction container. By this structure, an operating cost can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is an antifreeze-1 method for preventing surrounding strata from freezing in a low-temperature liquefied gas such as LPG or l-NG. Regarding the improvement of the neck, we attempted to reduce operating costs by using a P1-pump that utilizes the cold heat γI of the low-temperature shipping liquid.

[Conventional technology]

When storing low-temperature liquefied gases such as LPG (liquefied petroleum gas) and 1-NG (liquefied natural gas), side walls are installed in the ground-L type low) B storage (mediation layer) installed on the ground. Underground cryogenic storage tanks are used.

For example, in an underground low-temperature storage tank that is easy to harmonize with the surrounding I/F boundary, concrete is poured on the sides and bottom of a recess formed in the stratum to form a concrete bottom slab from Concrete 1 to the side walls. Low-temperature liquid can be poured into the interior ft'+ through an insulated cold insulator! j4 Build two! I2 shell structure
Often old.

In such an underground low-temperature storage tank, when low-temperature liquid is stored in the inner tank, it gradually leaks through the concrete side wall and -1 concrete bottom plate, despite the insulation and cold insulation (A) being installed on the outside of the inner tank. The surrounding strata are YOIned and frozen.

This causes expansion of the strata, etc., and a large pressure is applied to the concrete upper wall and the concrete bottom slab, which may cause In damage.

Therefore, in order to prevent freezing of the strata around the low-temperature storage tank, a heater is installed as an antifreeze device.

Freeze protection IL kot! (For example, as shown in Figure 3,
A side heater 3 made of heat transfer tubes is installed on the outer periphery of the side wall of a low-temperature storage tank 2 buried in a geological formation 1 and connected to a header, and a secondary side heat exchanger 5 is connected to the side heating circulation pump 4. While circulating the heated secondary hot water, a bottom heater 6 composed of a heat transfer tube was installed under the bottom plate of the low temperature storage tank 2, and the water was heated by the secondary bottom heat exchanger 8 by the circulation pump 7 for bottom heating. The secondary hot water is circulated.

The primary hot water, which serves as a heating source for the two secondary heat exchangers 5.8, is heated in the primary heat exchanger 9 by a heating medium such as steam from a boiler.

In addition, the side heaters 3 and the bottom heater 6 are each constructed of heat transfer tubes.1. ! In some cases, anti-freeze devices are used that consist of electric heaters and are heated directly by electricity.

[Problems that the invention attempts to solve]

In such an antifreeze device, operating costs are very high because steam or electricity is used as a heating source for the side heater 3 J3 and the bottom heater 6, and the management cost of the low humidity storage tank 2 is 30~/I.
There is a problem that the bond insurance burden is large, accounting for 0% of the total.

The present invention has been made in view of the prior art, and aims to provide a simple geological freeze prevention device for a low temperature storage tank, which reduces operating costs by utilizing the cold energy of the liquid shipped from the low temperature storage tank. That is.

Means for Solving Problem C] In order to solve the above problems, the present invention installs a heating heat exchanger close to the part of the low temperature storage tank buried in the stratum,
In this antifreeze device, which supplies a heating medium to a heat exchanger to prevent formations from freezing, two metal hydrides with different equilibrium characteristics with respect to pressure and temperature are filled into a reaction vessel, and the equilibrium pressure at the same temperature is high. 1 q of heat from a low heat source is applied to one reaction vessel filled with metal hydride to generate hydrogen gas due to the decomposition reaction of the metal hydride, or the extremely low heat of the low temperature shipping liquid in the low (!+a storage) is generated. A first heat exchanger is installed to absorb the heat generated by the metal hydride production reaction, and the high heat generated by the exothermic reaction between the gas and metal hydride is transferred to the other reaction vessel. The apparatus is characterized in that it is provided with a second heat exchanger which decomposes and regenerates the metal hydride by supplying the heating medium to the heat source or by using the heat from the low heat source.

[For production]

Low-temperature storage (freezing is prevented by supplying a heating medium to a heat exchanger installed close to the installation part in the corner stratum and covering it, but due to the heating of this heating medium, the temperature between two metal hydrides with different equilibrium properties In order to perform the decomposition reaction and production reaction reversibly by changing the pressure conditions, a low heat source such as seawater and the cold heat of the low-temperature shipping liquid are used.The heat generated by the production reaction is used to heat the metal hydride. J: Build a heat pump using sea urchin and cover it to prevent freezing of the geological formation, which is an inexpensive heat source.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

Figure 1 shows the cryogenic storage (a) geological freeze prevention device Ff of this invention
A schematic configuration diagram according to an embodiment of the present invention.

This freezing prevention ¥1id10 is applied to the underground low temperature storage tank 12 buried in the stratum 11, and the low temperature storage tank 1
An inlet header 1 with a larger diameter than the low-temperature storage tank 12 is installed on the ground surface around 2.
3a and an outlet header 13b are installed, and the low temperature storage f? f1
Heating tubes 13c formed of a large number of double tubes are arranged at equal intervals around the circumference close to the side wall of the header 2, and the inner tubes are connected to the inlet header 1.
3a, an outer tube is connected to an outlet header 13b, and a side heater 13 for side heating is constructed.

J: A heat exchanger tube 14a for b heating is arranged under the bottom plate of the low temperature storage tank 12 in a meandering manner or in a coil shape in accordance with the shape of the bottom plate, and a bottom heater 11I for heating the bottom is configured. .

A heating medium is supplied to these side heaters 13 and bottom heater 14 for heating.
It is heated using the heat generated by the pump 15.

In other words, primary hot water 16 is produced by heat exchange with the heat generated by 4q by the heat pump 15, and this secondary hot water 16 is supplied to the side heater 13 through the side heating circulation pump to be fed to the low temperature storage tank 12. The stratum 11 on the outer periphery of the side wall is heated, the heated primary hot water 16 is sent to the secondary drought heater 18 to heat the secondary hot water 19, and this secondary hot water 19 is sent to the bottom heater using the bottom heating circulation pump 20. 14 to heat the bottom plate of the low temperature storage tank 12.

This heat pump 15 uses two types of metal hydrides that have different equilibrium characteristics with respect to pressure and humidity, uses natural Z ice cubes, air, etc. as a low heat source, and [! However, the cold energy of the shipping liquid in the storage tank 12 is utilized.

The metal hydride is expressed in the following equation (1) with the J-reaction ISj characteristic. It is an endothermic reaction.

Here, Me: hydrogen storage alloy MOto IX, Me 1-IX+1/: metal water me 1
Compound Q: Heat of reaction.

Therefore, we investigated 62 types of metal hydrides Me 1-1x , M(! 1-1x
+y and M e' l-I X' M O' l-I X
' +V is used to configure pumps 1 to 15 that operate according to the cycle of one heater 1 and pump 4J as shown in FIG.

For example, metal hydrochloride Hcllx, Me tlx4
If V has a higher equilibrium pressure for the same temperature T, then its equilibrium characteristic ('t is in the figure, and the other metal hydride M O'I-1X', M (!'HX'
The equilibrium characteristic of 10V is 8 in the figure.

Then, the points on the heat pump cycle are a and b.

c, d, the quality and pressure corresponding to each point have the following physical meanings.

Ta: Temperature of a low heat source obtained from the natural world.

T1]: The temperature at which 1vl of J is applied to the heat pump.

Td: Extremely low temperature of the two-lower temperature shipping liquid.

Pa: Equilibrium pressure of metal hydride Me' +y at temperature 1a.

Pb: Temperature T b of metal hydride fVlol-1x
Knee 1j + J equilibrium pressure 1゜I'll: Temperature Td of metal hydride He'
equilibrium pressure.

PC; warm UTc of hydride Mcl-1x+y (=1-a
) to the equilibrium pressure of J5.

In this Bee 1-Pump 1 Nicle, first, between a and b (
d5, gold at point a B) water A; compound M O' I-(
x' +y When heated with a low heat source Ta such as in nature, the above formula (
The endothermic reaction on the right side of 1) occurs, and M Q' II X'
It decomposes into δ and hydrogen gas soot (2) is generated.

■ When this hydrogen gas -142 is supplied to one metal hydride Met-1x at point b and reacted, the reaction on the left side of the above equation (1) occurs and McHx+y is generated, and ■
The reaction heat Q at a higher temperature Tb is generated, and the reaction heat Q at a lower temperature is used for heating the heating medium.

Next, in order to regenerate the generated metal hydride Met-1x+y by a-ta between c-<1, it is set as ii at point 0.
A low heat source Tc (=Ta) such as water is heated to cause the reaction on the right side of the above equation (1) to produce (1) McHx and hydrogen gas-1-12.

Then, suppose that this hydrogen gas-1-12 is supplied to the metal hydride M O'HX' at point d to cause the reaction on the left side of the above equation (1) and regenerated to M e' t x' +y. , the reaction heat generated is Q8.
(By removing I, the reaction continues.

The metal hydride M O' l-I X' Fy thus regenerated is heated again at point a with a low heat source TQ such as seawater and used for the reaction between a and b.

According to such a heat pump cycle, high temperature reaction heat
This can be used to prevent the strata around the cryogenic storage tank from freezing.

Next, the specific configuration of the heat pump that performs this heat pump cycle will be explained.

Points a and b of the heat pump cycle in Figure 2.

c, d: 4. It! a (7) Set up reaction vessels 21, 22, 23, 24, and place metal hydride M e' in each reaction vessel 21, 22, 23, 24.
I-1x' +y.

Me lx, Me t-1x+y, Me'
Hx' is filled with tγ1, and the heat exchanger 25.
26, 27, and 28 to enable heating and cooling of the reaction vessel.

Then, the reaction vessels 21 and 22 are housed in one package 29 and connected by piping, and the reaction vessels 23 and 2/
I is placed in one package 3o and connected with piping, and the position of package 29 or 3o is exchangeable and J3 <
.

Heat exchangers 25 - provided in each reaction vessel 21 - 24
28, the heat exchanger (receiver 25.27 is supplied with heat from a low heat source in the natural world of sea water), and the reaction vessel 2
The second dry water 16 is circulated through the heat exchanger 26 of the reaction vessel 24, and the cold fJl is exchanged with the low-temperature shipping liquid 31 through the heat exchanger 32 and sent to the heat exchanger 28 of the reaction vessel 24. The cooled medium 33 is circulated by the circulation pump 31:
It's becoming a sea urchin.

J3, the heat exchange medium supplied to these heat exchangers 25 to 28 is that when the packages 29 and 30 are exchanged, the heat exchanger 25 receives the cooling medium 33, and the heat exchangers 26 and 28 receive the coolant from a low heat source. Heat is supplied to the primary hot water 16 to the heat exchanger 27, respectively.

In such a heat pump 15, the reaction between a and b of the heat pump cycle is carried out simultaneously in the two packages, and the reaction between C and 4 is carried out simultaneously in the package 30, and -
The next dry water 16 is heated and used to stop freezing.

Then, when the reaction in each package 29 and 30 is saturated, replace the bulkheads 29 and 30, and heat 1G of primary hot water using series 'F' and sea urchins.

Continuously heating the primary hot water 16, metallic water: (
It is also possible to regenerate the compound tvlcHx in a dormant state. It is preferable that the exchanger 2G be capable of switching between the primary hot water 16 and the il+7 water.

In addition, as the metal hydride used in the pumps 1 to 15, for example, lanthanum nickel and Mitsushi metal nickel iron can be used, and these can be used in low-temperature storage tanks for LNG and LPG. 12, the equilibrium temperature T J of each point a to d of the heat pump cycle
j J: and equilibrium pressure] P is, for example, the following value J:' When secondary hot water of about 15°C is heated to about 50°C,
This can be used to prevent freezing.

a (ladle 20℃, approx. 11 K9/cfflabs)
.

b (approximately 60'C, approximately 7 to 9/ciabs).

C (approx. 10℃, approx. IK'J/cnf abs
).

d (approximately -40℃, approximately O07 to 9/aj abs
).

<K J3, As for metal hydrides, various kinds of lanthanum nickel and Mitshu metal nickel and Mitshu metal nickel, iron and ditanium 1:1 mu manganese can be used. It's a monkey.

J: The target for freezing prevention is the side wall J'3 of the above-ground cryogenic storage tank.
J: Applicable not only to the strata around the bottom slab, but also to the strata around the slab of an above-ground low temperature storage tank.

[Effects of the Invention] As specifically explained in Section 1 above-Execution 1, according to the present invention, exothermic reactions and endothermic reactions due to the production and decomposition of two types of metal hydrides with different equilibrium characteristics with respect to pressure and temperature can be achieved. A pump is configured using the reaction, and this heat pump is operated using a low heat source such as seawater and the cold heat of the low temperature shipping liquid as a heat source, and the high temperature reaction heat is used to generate a low heat pump. fli
Because it heats the strata around the storage tank to prevent freezing, operating costs can be significantly reduced compared to conventional antifreeze devices that use steam or electricity as their heat source.

Furthermore, the cold energy of the low-temperature shipping liquid can be effectively used, and even when the liquid is heated with a heater during shipping as in the conventional case, the energy can be saved, resulting in energy saving V of the low-temperature storage tank system.

In general, this anti-freeze device has no moving parts, so it can be used to control the operation of circulation pumps, etc., and is easy to maintain and highly reliable.

In addition, the structure of the device is simple, making it easy to apply to conventional devices.
It's easy.

4. Figure 1 is a schematic diagram of an embodiment of a geological freeze prevention device for a low crystal storage tank according to the present invention, and Figure 2 is an explanation of a bomb tank using a metal hydride. FIG. 3 is a schematic configuration diagram of a conventional device.

10... Freeze prevention device, 11... Geological stratum, 12...
Low humidity/storage tank, 13...Side heater, 14...Bottom heater, 15...P1~pump, 16...-Next hot water, 17...Circulation pump for side heating, 18... - Secondary drought heater, 19... Secondary hot water, 20... Bottom heating circulation pump, 21-24... Reaction vessel, 25-28.
...Heat exchanger, 31...Low temperature shipping liquid.

Claims (1)

[Claims] In an anti-freeze system that installs a heating heat exchanger close to the part of the low-temperature storage tank buried in the stratum and supplies a heating medium to the heat exchanger to prevent the stratum from freezing, equilibrium characteristics with respect to pressure and temperature are used. Two metal hydrides with different values are filled into reaction vessels, and one reaction vessel filled with a metal hydride at the same temperature and higher equilibrium pressure receives heat from a low heat source to cause a decomposition reaction of the metal hydride. A first heat exchanger is provided that generates hydrogen gas or uses the cold heat of the low-temperature shipping liquid in the low-temperature storage tank to absorb the heat generated by the metal hydride production reaction,
A second step for decomposing and regenerating the metal hydride by supplying high heat from the exothermic reaction between the hydrogen gas from the one reaction container and the metal hydride to the other reaction container, or by obtaining heat from the low heat source. A geological freeze prevention device for a low temperature storage tank characterized by being equipped with a heat exchanger.