JPH09158522A - Heater equipment for low temperature liquefied gas tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the temperature control easier and improve durability by filling up a gap space between the side wall of a cylindrical underground tank and a cut-off wall with crushed stone, pouring hot water from the top of the crushed stone layer and draining from a bottom portion thereby circulating hot water through a heat exchanger. SOLUTION: A gap between the exterior wall 15 of a low temperature liquefied gas tank 1 and a cut-off wall 9 is filled up with crushed stone thereby forming a cylindrical crushed stone layer 21; and hot water is poured from the top with a ring-shaped hot water supply pipe 23 thereby heating the crushed stone layer 21 and preventing freezing in nearby ground 3. Also, hot water poured into the crushed stone layer 21 is collected by a conduit tube 27 and pumped up above the ground with a storage pump 29; and water temperature is raised by a heat exchanger 33, supplied to a hot water supply pipe 23 and circulated for use. Moreover, a crushed stone layer 16 is formed at the lower side of a tank bottom plate 13, and freezing of the bottom ground 3 is prevented in the same manner as side wall 15. And the temperature control of the circulating hot water is made easier. By doing this, the heater facilities with excellent durability can be obtained at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater facility for controlling the freezing range of the ground around a low temperature liquefied gas tank.

[0002]

2. Description of the Related Art Generally, in a low temperature liquefied gas tank for storing LNG (liquefied natural gas) or the like, LNG is -162 degrees Celsius.
Since the temperature is extremely low, there is a problem that the surrounding ground freezes. Conventionally, in order to prevent the freezing line, which is the boundary between the frozen part and the non-freezing part of the surrounding ground, from spreading outward, heater equipment is provided to prevent the growth of the frozen part and control the position of the freezing line. For this heater equipment,
Side heaters, crushed stone heaters, etc. are used.

In the conventional side heater, heater tubes are vertically installed at a predetermined pitch in the ground outside the tank body, and hot water is passed through the heater tubes. As the heater pipe, a pipe for outgoing water and a pipe for returning water that are vertically provided are connected at the deepest portion to allow hot water to pass therethrough, or a double pipe is provided to make the inner pipe for outgoing hot water and return for the outer pipe. There are things to use.

FIG. 5 is a vertical sectional view of a conventional low temperature liquefied gas tank 101, showing a case where a double tube consisting of an inner tube and an outer tube is used as a heater tube 103. When constructing the underground tank 101 in the ground 105, first, a vertical water blocking wall 109 is provided in an annular shape so as to reach the impermeable layer 107 having an appropriate depth and layer thickness. The water blocking wall 109 is also used as a mountain retaining wall, and the water blocking wall 10 will be used in the next stage.
The inside of 9 is excavated to the flooring position 111.

Then, a cylindrical side wall 115 is constructed along the inner surface of the water blocking wall 109 so as to come into full contact, a crushed stone layer 157 is provided at the flooring position 111, and a bottom slab 113 is constructed above the crushed stone layer 157.

A domed roof 117 is provided on the side wall 115.
Is placed. Further, the heater tubes 103 are arranged outside the water blocking wall 109 at a predetermined pitch. Hot water is circulated inside the heater tube, and the cooled hot water is circulated during the heat exchanger 11
Reheat with 9 or the like. Since the degree of cooling of the hot water varies depending on the storage amount of the low temperature liquefied gas 102 and the like, the temperature of the hot water is constantly monitored by a thermometer (not shown) and the heat exchanger 11
The heating amount by 9 is determined.

FIG. 6 shows the conventional heater tube 10 shown in FIG.
FIG. 7 is a horizontal cross-sectional view showing the shape of a freeze line around the side of the low temperature liquefied gas tank 101 when No. 3 is used. Heater tube 1
Since the ground is warmed closer to 03, the position of the freezing line is closer to the center of the tank around each heater tube 103, and farther from each heater tube 103, the farther from the center of the tank. Therefore, the freezing line 121 has a waveform as shown in FIG.

FIG. 7 is an explanatory view of the principle of the conventional crushed stone layer heater 151. The crushed stone layer heater 151 includes the tank body 155 (the side wall 115 and the bottom plate 11) of the low temperature liquefied gas tank 101.
A crushed stone layer 157 is laid in the shape of a disc with a predetermined thickness below 3), and warm water is passed through the crushed stone voids to form the tank skeleton 155.
It controls the freezing line of the ground around the lower part of. The warm water is supplied to the crushed stone layer 157 from the lower part of the supply pit 159 and pumped from the pumping pit 161.

[0009]

However, the conventional heater equipment for a low temperature liquefied gas tank using a heater tube has the following problems. That is, a) Since the heater tubes are installed at a predetermined interval as shown in FIGS. 5 and 6, the freezing line has a waveform as shown in FIG. 6, and the operation management of the heater equipment is difficult.

B) Since a large number of heater tubes are installed, the construction period becomes long. c) The cost of the heater tube equipment is high. d) Problems such as corrosion of the heater tube occur during long-term use.

The present invention has been made in view of the above problems, and an object of the present invention is that the freezing line is almost a circle and temperature control is easy, construction is easy, construction period is short, and construction cost is low. Is to provide a heater equipment for a low temperature liquefied gas tank that is inexpensive and has good durability.

[0012]

In order to achieve the above-mentioned object, the present invention is a heater equipment for controlling freezing of the ground around a low temperature liquefied gas tank provided in the ground, wherein the low temperature liquefied gas tank A first crushed stone portion provided on an outer periphery of a side portion of the tank skeleton, and an injecting means for injecting warm water into a void of the first crushed stone portion from an uppermost portion of the first crushed stone portion; It comprises a discharge port for discharging water from below the crushed stone portion, a pumping device for pumping the water discharged from the discharge port to the injection means, and a heating device for warming the pumped water. This is a heater equipment for a low temperature liquefied gas tank. In the present invention, a crushed stone portion is provided on the outer periphery of the side portion of the tank body, and hot water is injected from above the crushed stone portion to form a side heater.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a vertical sectional view showing a schematic configuration of a low temperature liquefied gas tank 1 according to the present embodiment, and FIG. 2 is a horizontal sectional view taken along line HH of FIG.

When constructing the low temperature liquefied gas tank 1 for storing the low temperature liquefied gas 2 in the ground 3, first, a vertical stop is made so as to reach the impermeable layer 7 having an appropriate depth and layer thickness from the ground surface 5. The water wall 9 is provided in an annular shape. The water blocking wall 9 is also used as a mountain retaining wall, and the inside of the water blocking wall 9 is excavated to the floor-attached position 11.

Then, a bottom crushed stone layer 16 having a predetermined thickness is provided at the flooring position 11. The bottom crushed stone layer 16 is used as a crushed stone layer heater (bottom crushed stone layer heater). Bottom crushed stone layer 1
Build a bottom plate 13 on top of 6.

While constructing an annular side wall 15 having an outer radius smaller than the inner radius of the water stop wall 9 by a length A, a gap of thickness A between the water stop wall 9 and the side wall 15 is filled with crushed stone. , The side crushed stone portion 21. Dome-shaped roof 1 on the side wall 15
7 is placed. The tank body 19 includes a side wall 15 and a bottom plate 13.
Consists of An annular hot water supply pipe 23 is provided above the side crushed stone portion 21. The hot water supply pipe 23 is provided with holes for releasing hot water at predetermined intervals, and hot water is supplied as shown in FIG.

The crushed stone size of the side crushed stone portion 21 and the filling method can discharge a sufficient amount of heat when the voids of the crushed stone are filled with hot water, and can reduce the load of the tank body 19 and the low temperature liquefied gas 2 It is determined so that it can be supported and the buoyancy acting on the tank body 19 due to the hot water in the void does not become excessive.

The temperature, the supply rate or the supply amount of the hot water are
It is determined by controlling the freezing line in the surrounding ground 3 by a thermometer (not shown) arranged at a predetermined position. The warm water is radiated and cooled as it flows downward of the side crushed stone portion 21.

The bottom surface of the side crushed stone portion 21 is inclined,
For example, several places on the bottom surface are made the lowest so that water having a lowered temperature is accumulated. 25 shows the deepest part. A drainage port is provided at the deepest point 25, and a water guiding pipe 27 that penetrates from the discharge port to the outside of the water blocking wall 9 is provided.
A pumping pump 29 is provided outside the water conduit 27, and a pumping pipe 31 is provided.
Water is led to the heat exchanger 33 provided on the ground.

In the heat exchanger 33, the cold water is warmed to hot water of a predetermined temperature, and the hot water supply pipe 23 is supplied through the supply pipe 35.
To supply. The hot water discharged from the hot water supply pipe 23 flows down the side crushed stone portion 21, and the pumping pump 2 from the water conduit 27.
Reach 9. That is, the side crushed stone portion 21 functions as a side heater. Hot water is supplied to the bottom crushed stone layer 16 by another method.

As described above in detail, according to the present embodiment, a cylindrical surface heater can be constructed instead of the line heater as in the conventional heater tube.
As shown in, the shape of the freezing line 37 is close to a circle, and temperature control is easy.

Further, as compared with the case where a large number of heater tubes are installed, the construction is easy, the construction period is short, and the construction cost is low. Further, the heater tube is not corroded, which has been a problem when the heater tube is used for a long period of time, and the durability of the heater equipment is good.

In this embodiment, the hot water circulating method is such that separate hot water is supplied to the side crushed stone portion 21 and the bottom crushed stone layer 16, but both the side crushed stone portion 21 and the bottom crushed stone layer 16 are supplied. The same hot water may pass through.

[0024]

As described above in detail, according to the present invention, the freezing line is close to a circle and temperature control is easy,
It is possible to provide a heater equipment for a low temperature liquefied gas tank that is easy to construct, has a short construction period, is inexpensive to construct, and has good durability.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a low temperature liquefied gas tank 1.

FIG. 2 is a horizontal sectional view taken along line HH of FIG.

FIG. 3 is a diagram showing the supply of hot water.

FIG. 4 is a diagram showing the shape of a freeze line.

FIG. 5 is a vertical sectional view of a conventional low temperature liquefied gas tank 101.

FIG. 6 is a horizontal sectional view showing the shape of a freezing line when a conventional heater tube 103 is used.

FIG. 7 is an explanatory view of the principle of a conventional crushed stone layer heater 151.

[Explanation of symbols]

 1 ...... Low-temperature liquefied gas tank 2 ...... Low-temperature liquefied gas 3 ………… Soil 5 ………… Ground surface 7 ………… Impermeable layer 9 ………… Water blocking wall 11 ………… Floor mounting position 13 ………… Bottom slab 15 ………… Side wall 16 ………… Bottom crushed stone layer 17 ………… Roof 19 ………… Tank frame 21 ………… Side crushed stone portion 23 ………… Hot water supply pipe 25 ………… Deepest point 27 ………… Water pipe 29 ... Pumping pump 31 ... Pumping pipe 33 ... Heat exchanger 35 ... Supply pipe

Claims (2)

[Claims] 1. A heater facility for controlling the freezing of the ground around a low temperature liquefied gas tank provided in the ground, wherein the first crushed stone portion is provided on the outer periphery of the side of the tank body of the low temperature liquefied gas tank. An injecting means for injecting hot water into the void of the first crushed stone portion from the uppermost portion of the first crushed stone portion; a discharge port for discharging water from below the first crushed stone portion; A heater equipment for a low temperature liquefied gas tank, comprising: a pumping device for pumping the discharged water to the injection means; and a heating device for warming the pumped water. 2. A second crushed stone portion provided below the tank skeleton, wherein hot water injected from the uppermost portion of the second crushed stone portion flows into the second crushed stone portion. The heater equipment for a low temperature liquefied gas tank according to claim 1.