JPH08178190A - Device for suppressing BOG generated in LPG storage tank - Google Patents

Abstract

(57) [Summary] [Objective] In a device for suppressing BOG generated in an LPG storage tank, the equipment is reduced, the BOG suppression operation cost is reduced, and the prompt response of control is improved. [Structure] An LPG storage tank 1 is equipped with an injection nozzle 16 for injecting an injection liquid in a divergent manner at an upper portion thereof, and an LPG
The LPG supercooled by the heat exchanger 7 is supplied to the injection nozzle 16
By injecting in a divergent manner from the inside, the injection liquid in the portion close to the canopy 1a having a large heat input is localized, and the pressure in the LPG storage tank 1 is detected by the pressure detection sensor 15
The LPG control valve 5 and the supercooling liquid control valve 12 are automatically controlled by the control device 14 so that the pressure value becomes a set value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for suppressing BOG generated in an LPG storage tank.

[0002]

2. Description of the Related Art In the LPG storage tank, BOG is generated due to natural heat input or the like, and the tank internal pressure rises. Therefore, it is necessary to take measures to suppress the generation of this BOG. The following are known examples.
An LPG that was once pumped out from the LPG storage tank by installing a diffusion type spray device in the upper part of the LPG storage tank.
Was supercooled by using a supercooling liquid such as LNG, and this was sprayed into the tank from the spray device to generate BOG.
Is reliquefied (Japanese Utility Model Laid-Open No. 64-31299).

[0003]

However, the above-mentioned known example has the following drawbacks. In the LPG storage tank, since the spray device is attached to a position close to the canopy, the temperature in the gas phase is supercooled to a position close to the canopy. For this reason, the temperature difference between the inside and the outside of the canopy with the highest heat input is wide in a wide range, the relative heat input increases, and the BOG suppression effect decreases. This leads to increase in operating costs. Moreover, in the case of the above-mentioned known example, B
OG cannot be suppressed (poor responsiveness).

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the constitution thereof is as follows. 1. LPG extracted from the LPG storage tank is LPG
Supercool with supercooling liquid in a heat exchanger,
In a BOG suppressing device for returning to a gas phase in a PG storage tank to suppress BOG generated in an LPG storage tank, an injection nozzle for injecting supercooled LPG in a divergent manner is provided in an upper part of the LPG storage tank. Installed
A flow sensor and an LPG control valve are attached to an LPG branch line that guides LPG to the LPG heat exchanger,
Supercooled LPG from LPG heat exchanger into LPG storage tank
A supercooled LPG temperature detection sensor is attached to the supercooled LPG line for sending the supercooled LPG line, and a supercooled liquid flow rate sensor and a supercooled liquid control valve are further installed in the supercooled liquid branch line for sending the supercooled liquid to the LPG heat exchanger. Installed
An LPG storage tank internal pressure detection sensor is attached to the LPG storage tank, and is detected by the LPG storage tank internal pressure detection sensor based on the flow rate detected by each of the flow rate sensors and the temperature detected by the supercooled LPG temperature detection sensor. A control device for controlling the LPG control valve and the supercooling liquid control valve so that the pressure to be set becomes a set value, a device for suppressing BOG generated in an LPG storage tank is provided. 2. 1. In the above-mentioned 1, a device for suppressing BOG generated in an LPG storage tank using a perforated plate type injection nozzle. 3. 1. The device for suppressing BOG generated in an LPG storage tank according to the above 1, which is formed by using a tip spray type injection nozzle. 4. In 1 or 2 or 3 above, LN is used as a supercooling liquid.
A device for suppressing BOG generated in an LPG storage tank using G.

[0005]

The LPG supercooled by the LPG heat exchanger is injected from the injection nozzle into the gas phase of the LPG storage tank. At the time of this injection, the injection nozzle spreads the supercooled LPG in a diverging manner, that is, the injection surface area of the portion near the canopy of the LPG storage tank is small, and the supercooled LPG becomes larger toward the bottom.
Since it has the characteristic of injecting G, the injection area near the canopy, which receives a lot of heat, is localized. This localization effect reduces heat input and effectively suppresses BOG. next,
The pressure in the LPG storage tank is constantly detected by the pressure sensor, and the control device immediately suppresses the supercooled LPG amount and the supercooled liquid amount so that the pressure becomes the set value.

[0006]

FIG. 1 shows an embodiment of the present invention, in which 1 is LPG.
Storage tank, 1a canopy, 2 LPG pump, 3 LP
G pumping line, 4 pumping LPG branch line, 5
Is an LPG control valve, 6 is an LPG temperature detection sensor, 7 is an LPG heat exchanger, 8 is a supercooled LPG line, 9 is a supercooled LPG temperature detection sensor, 10 is a supercooled liquid (LNG) line, and 11 is a supercooled liquid. A branch line, 12 is a supercooling liquid control valve, 13 is a supercooling liquid temperature detection sensor, 14 is a control device, 15 is a pressure detection sensor in the LPG storage tank 1, and the control device 14 is a pressure detection sensor 15. LPG control valve 5 so that the detected pressure maintains the set pressure.
And the supercooling liquid control valve 12 is controlled. 16 is LPG
An injection nozzle attached to a position close to the canopy 1a in the storage tank 1, and an inlet side of the injection nozzle 16 is connected to the supercooling LPG line 8.

2A and 2B show the injection nozzle 1
The sixth embodiment (A) is a so-called perforated nozzle configured so that a large number of injection holes 17 are provided on the front surface of the nozzle and the supercooled LPG can be injected in a divergent manner. . On the other hand, in the case of (B), the tip 18 is
Is a so-called tip spray type nozzle configured so as to be capable of injecting supercooled LPG in a divergent manner. In addition, this injection nozzle 16 is (A),
The method is not limited to (B), and any method of spraying in a divergent manner can be used. Further, the injection nozzle 16 of the embodiment is only attached to the center of the upper part of the tank, but a plurality of injection nozzles 16 may be attached.

In the above embodiment, the LPG supercooled by the LPG heat exchanger 7 is sprayed from the spray nozzle 16 toward the liquid surface in the LPG storage tank 1 in a divergent manner. As a result, the BOG in the gas phase is cooled and reliquefied. The control device 14 detects the pressure in the tank by the pressure detection sensor 15, calculates the amount of supercooled LPG and the amount of supercooled liquid to be injected, and controls the LPG control valve 5 and the supercooled liquid control valve 12.

[0009]

As described above, according to the present invention, when the supercooled LPG is returned to the LPG storage tank, the injection nozzle is selected so that the injection liquid is localized. In the region close to
PG is localized. Therefore, the area of the portion where the temperature difference between the inside and outside is large is small, while the supercooled LPG is directed downward.
Since the contact area between the BOG and the BOG is large, it is possible to effectively suppress the amount of BOG generated while preventing heat input from the canopy. As a result, when compared with the above-mentioned conventional technology,
It is possible to reduce BOG suppression equipment and reduce BOG suppression operating costs. Further, according to the present invention, the amount of supercooled LPG (amount to be injected) and the amount of supercooled liquid are automatically controlled by the control device so that the tank internal pressure becomes the set value, so the responsiveness and stability are improved. .

[Brief description of drawings]

FIG. 1 is an explanatory view of an apparatus for suppressing BOG generation according to the present invention.

FIG. 2 is an explanatory diagram of an embodiment of a supercooled LPG injection nozzle.

[Explanation of symbols]

 1 LPG storage tank 2 LPG pump 3 LPG pumping line 4 LPG pumping branch line 5 LPG control valve 6 LPG temperature detection sensor 7 LPG heat exchanger 8 Supercooling LPG line 9 Supercooling LPG temperature detection sensor 10 Supercooling liquid line 11 Supercooling Liquid branch line 12 Supercooling liquid control valve 13 Supercooling liquid temperature detection sensor 14 Control device 15 Tank pressure detection sensor 16 Injection nozzle 17 Hole 18 Chip

Claims (4)

[Claims] 1. An LP pumped out from an LPG storage tank
A BOG suppressing device for supercooling G in a LPG heat exchanger using a supercooling liquid, returning it to a gas phase in the LPG storage tank, and suppressing BOG generated in the LPG storage tank. A supercooled LP that spreads out in the upper part of the inside
An injection nozzle for injecting G is attached, a flow rate sensor and an LPG control valve are attached to an LPG branch line for guiding LPG to the LPG heat exchanger,
Supercooled LPG from LPG heat exchanger into LPG storage tank
A supercooled LPG temperature detection sensor is attached to the supercooled LPG line for sending the supercooled LPG line, and a supercooled liquid flow sensor and a supercooled liquid control valve are further installed in the supercooled liquid branch line for sending the supercooled liquid to the LPG heat exchanger. The LPG storage tank pressure detection sensor is attached to the LPG storage tank, and the LPG storage tank pressure detection is performed based on the flow rate detected by each of the flow rate sensors and the temperature detected by the supercooling LPG temperature detection sensor. A control device for controlling the LPG control valve and the supercooling liquid control valve so that the pressure detected by the sensor becomes a set value, and a control device for BOG generated in the LPG storage tank, comprising: 2. The device for suppressing BOG generated in an LPG storage tank according to claim 1, wherein the perforated plate injection nozzle is used. 3. The B generated in the LPG storage tank according to claim 1, which is formed by using a tip spray type injection nozzle.
OG suppression device. 4. The device for suppressing BOG generated in an LPG storage tank according to claim 1, 2 or 3, wherein LNG is used as a supercooling liquid.