JP2000130695A - Method of reserving natural gas in absorption type natural gas storage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of reserving a natural gas in an absorption type natural gas storage tank, which can restrain adsorbent from raising its temperature when the natural gas is reserved in the storage tank. SOLUTION: A liquefied natural gas is fed into an adsorption type natural gas storage tank 12 mounted on a natural gas engine automobile and incorporated therein with adsorbent, from an LNG tank 10. In this phase, the quantity of a liquefied natural gas fed into the storage tank 12 is monitored by a pressure sensor 16. When the pressure detected by the pressure sensor 16 reaches a predetermined value, a shut-off valve 18 is closed so as to stop the supply of the liquefied natural gas. Since the temperature of the liquefied gas is low, the temperature rise of the adsorbent caused by heat of adsorption when the natural gas being adsorbed to the adsorbent in the tank 12, can be held to be low, thereby it is possible to restrain the adsorbed amount from lowering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for storing natural gas in a storage natural gas storage tank containing an adsorbent therein.

[0002]

2. Description of the Related Art Conventionally, as a natural gas storage tank mounted on a natural gas vehicle or the like that uses natural gas as a fuel, a storage type natural gas storage tank that contains an adsorbent therein and adsorbs and stores natural gas is known. Are known. In such a storage natural gas storage tank, at a relatively low pressure,
There is an advantage that a large amount of natural gas can be stored.

[0003]

However, for example, GRI (Gas Research Institute) in the United States
e) As pointed out in the report, when compressed natural gas is filled into a storage natural gas storage tank, heat of adsorption is generated by the adsorption of natural gas to the adsorbent, and the temperature of the adsorbent rises. Therefore, there is a problem that the amount of natural gas adsorbed is greatly reduced.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to store natural gas in a storage natural gas storage tank and suppress the rise in temperature of the adsorbent. It is to provide a method for storing natural gas in a storage tank.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method for storing natural gas in a storage type natural gas storage tank which contains an adsorbent and adsorbs and stores natural gas. It is characterized by supplying natural gas in gaseous state.

[0006]

Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 shows an example of an apparatus for carrying out a method for storing natural gas in a storage-type natural gas storage tank according to the present invention. A feature of this embodiment is that when supplying natural gas to the storage type natural gas storage tank, low temperature liquefied natural gas (LNG) is used instead of high temperature compressed natural gas (CNG). On the point.

In FIG. 1, an LNG tank 10 in which a liquefied natural gas is stored at a natural gas filling station is stored in a natural gas vehicle or the like, and a storage type of natural gas stored in an adsorbent is stored. Liquefied natural gas is supplied to the tank 12. The LNG tank 10 and the storage tank 12 are connected by a coupler 14. When liquefied natural gas is supplied from the LNG tank 10, the pressure of the storage tank 12 increases.
Is monitored, and when a predetermined pressure is reached, a detection signal is output from the pressure sensor 16, and the shutoff valve 18 is closed by this signal. Thereby, when a predetermined amount of liquefied natural gas is supplied from the LNG tank 10 to the storage tank 12 due to the pressure of the storage tank 12, the supply of the natural gas is stopped. Since natural gas is in a liquid state, it is not immediately adsorbed by the adsorbent stored in the storage tank 12, but is gradually adsorbed within a predetermined time.

The amount of liquefied natural gas to be supplied to the storage tank 12 at the time of filling can be determined by the volume of the storage tank 12, the amount of the adsorbent, the adsorption characteristics of the adsorbent, and the like. The method of measuring the supply amount of the liquefied natural gas to the storage tank 12 is not limited to the pressure sensor 16, but may be a level sensor or the like.

As described above, in the present invention, since natural gas is supplied in the state of liquefied natural gas to the storage tank 12 containing the adsorbent, even if heat of adsorption is generated during adsorption to the adsorbent, Since the temperature of the liquefied natural gas is low, it is possible to suppress the temperature of the adsorbent from increasing and the amount of adsorption from decreasing.

FIG. 2 shows another example of an apparatus for carrying out the method for storing natural gas in the storage type natural gas storage tank according to the present invention. In FIG. 2, the storage tank 12
Are provided, and a shutoff valve 18 is provided between the storage tank A and the storage tank B. Further, unlike the case of FIG. 1, the pressure sensor 16 for measuring the amount of the liquefied natural gas in the storage tank 12 is not provided.
When supplying liquefied natural gas to the storage tanks A and B from the LNG tank 10 on the filling station side, the shut-off valve 18 is closed,
Liquefied natural gas is supplied only to storage tank A. When the liquefied natural gas is supplied to the storage tank A until it is full, the supply of the liquefied natural gas to the storage tank A is stopped. This point is set as the end point of the liquefied natural gas supply. In this state, the natural gas vehicle can be started at any time.

After the supply of liquefied natural gas from the LNG tank 10 is completed, the shut-off valve 18 is opened. As a result, the liquefied natural gas that cannot be completely adsorbed by the adsorbent in the storage tank A is supplied to the storage tank B via the shutoff valve 18 and is adsorbed by the adsorbent in the storage tank B. As described above, the volume of the storage tank A and the storage tank B is determined by the storage tank B when the storage tank A is full.
The relationship may be such that it can be adsorbed.

In FIG. 2, if the adsorbent contained in the storage tank A can adsorb all of the liquefied natural gas supplied to the storage tank A until it becomes full, the storage tank B becomes unnecessary. FIG. 3 shows an example in which such an adsorbent is used for the storage tank 12.

In FIG. 3, a pressure sensor 16 for measuring the amount of liquefied natural gas supplied to the storage tank 12, a storage tank B for adsorbing liquefied natural gas which cannot be adsorbed, and the like are not provided. This is because it contains an adsorbent capable of adsorbing all of the liquefied natural gas supplied to the storage tank 12. Thereby, when the storage tank 12 is filled, the storage tank 1 is always transferred from the LNG tank 10 on the filling station side.
It is sufficient to supply liquefied natural gas until 2 is full.

In each of the embodiments described above, the rate of supplying liquefied natural gas to the storage tank 12 can be made higher than the rate of supplying liquefied natural gas in the state of compressed natural gas, so that the filling time can be shortened. . This is because, in the case of compressed natural gas, the filling rate depends on the adsorption rate of methane, so that it takes a certain amount of time. In the case of liquefied natural gas, the liquid only needs to enter the storage tank 12, and the adsorption is This is because the operation is performed in a predetermined time after that, and the suction speed can be increased because the suction speed does not depend on the suction speed.

Further, in a normal liquefied natural gas storage tank, when the pressure in the tank rises, this is released into the atmosphere to adjust the pressure, so that the loss of natural gas increases. On the other hand, according to the present invention, since the storage type natural gas storage tank is used, the pressure is relatively low and stable even at room temperature. As a result, there is no need to release natural gas into the atmosphere, and natural gas loss can be reduced.

[0017]

As described above, according to the present invention,
Natural gas is supplied to the storage natural gas storage tank containing the adsorbent in the form of liquefied natural gas instead of compressed natural gas. As a result, the supply speed of the natural gas can be increased, and the charging time can be reduced.

Since the temperature of liquefied natural gas is low,
Even if heat of adsorption is generated when natural gas is adsorbed by the adsorbent in the storage tank, an increase in the temperature of the adsorbent can be suppressed, and a decrease in the amount of adsorption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an apparatus for performing a natural gas storage method in a storage type natural gas storage tank according to the present invention.

FIG. 2 is a diagram showing another example of an apparatus for performing the natural gas storage method in the storage type natural gas storage tank according to the present invention.

FIG. 3 is a view showing still another example of the apparatus for performing the natural gas storage method in the storage type natural gas storage tank according to the present invention.

[Explanation of symbols]

10 LNG tank, 12 storage tank, 14 coupler, 16 pressure sensor, 18 shut-off valve.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukio Terashima 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3E072 AA03 DA04 EA10 3E073 AA05 DA04

Claims (1)

[Claims] 1. A method for storing natural gas in a storage type natural gas storage tank containing an adsorbent and adsorbing and storing natural gas, wherein the natural gas is supplied in a liquefied natural gas state. Natural gas storage method in natural gas storage tank.