JPH04169780A - Solid hydrogen generator - Google Patents

Abstract

PURPOSE:To improve a cooling efficiency by forming cooling means of a freezing material supply unit for feeding a freezing material under pressure to a solid hydrogen generation unit, and a discharge unit for discharging the material which has cooled the generation unit out of a vacuum vessel, and providing an exhaust pump for forcibly exhausting the material in the discharge unit. CONSTITUTION:Cryogenic heads 2, 3 are cooled to a predetermined temperature by evaporating supplied LHe, and He becoming a state containing partial LHe is forcibly sucked and discharged out of a vacuum vessel 1 through exhaust conduits 55a, 55b by the operations of vacuum pumps 57a, 57b. Since the He which has cooled the heads 2, 3 is sucked by the pumps 57a, 57b in the cooling of the heads 2, 3, the pressures of the heads 2, 3 side can be reduced as compared with that when the vacuum pumps are not provided. Thus, the heads can be cooled to lower temperature than that of a prior art device, thereby improving its cooling efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a solid hydrogen generation device that cools and solidifies hydrogen or hydrogen isotopes such as hydrogen, deuterium, or tritium.

[Conventional technology]

Conventionally, a hydrogen pellet injection device, for example, is known as a solid hydrogen generation device. This method generates hydrogen pellets by cooling and solidifying hydrogen gas, and injects the hydrogen pellets into the plasma of a fusion plasma experimental device, and is used to control the plasma particle density.

As the above-mentioned hydrogen pellet injection device, the one shown in Fig. 3 has been proposed (for example, Japanese Patent Application No. 62-2689
(See Publication No. 84). This consists of a vacuum container a, a pair of cryoheads b placed in the vacuum container a, a pellet carrier disk C placed between the pair of cryoheads b, and the pellet carrier disk C brought to an extremely low temperature. It has a cooling means d for cooling, a hydrogen gas supply means e for supplying hydrogen gas for hydrogen pellets, and a high pressure gas supply means f for firing hydrogen pellets, and the supplied hydrogen gas is cooled and solidified to form pellets. carrier disc C
Hydrogen pellets are generated in the plasma, and the hydrogen pellets are ejected by high-pressure gas, guided through a gun barrel g, and injected into the plasma.

The cooling means d includes a cold material supply section that pumps liquid helium (hereinafter referred to as LHe) as a cold material to a pair of cryoheads b, and extracts the LHe after heat exchange to the outside of the vacuum vessel a by the pressure difference. hot water tank i
Helium gas (hereinafter referred to as GHe) is completely vaporized by
It consists of a discharge part j that discharges the water outside the system.

In the cryohead b, the amount of heat of evaporation of LH+ is required to be greater than the amount of heat flowing into the cryohead b by conduction and radiation, and based on this, the amount of LHe supplied from the cold material supply section is determined. .

In this cold material supply section, a pumping pressure corresponding to the amount of LHe is applied, whereby a predetermined amount of LHe is supplied to the cryohead b.

[Problems to be Solved by the Invention] In a conventional solid hydrogen generation device, in order to generate high quality hydrogen pellets, it is necessary to cool the cryohead to a certain temperature or lower. For this reason, an operation is performed to increase the pressure for feeding the LH+ in accordance with this temperature, thereby increasing the amount of LHe supplied.

However, as the pumping pressure increases, the evaporation temperature of LHe also increases, so the cooling temperature does not decrease even though the amount of LHe increases, and the conventional device described above cannot be fully satisfied in terms of cooling efficiency. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid hydrogen generator that can improve cooling efficiency.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a vacuum container, a solid hydrogen generation section disposed in the vacuum container, a cooling means for cooling the solid hydrogen generation section to an extremely low temperature, and a solid hydrogen generation section. In the solid hydrogen generation device having a hydrogen gas supply means for supplying hydrogen gas, the cooling means includes:
It consists of a cold material supply section that pumps the cold material to the solid hydrogen generation section, and a discharge section that discharges the cold material after cooling the solid hydrogen generation section out of the vacuum container. The structure is equipped with an exhaust pump that forcibly evacuates the material.

[Effect]

According to the above configuration, the LHe pressure in the cryohead is lowered due to forced evacuation by the evacuation pump than when evacuation is performed simply by a pressure difference with atmospheric pressure in the conventional apparatus. The evaporation temperature of LHe decreases as the pressure decreases, so the evaporation temperature of LHe supplied to the cryohead decreases by the amount that the pressure decreases. The amount of heat of evaporation increases and the cryohead is cooled to a lower temperature.

Therefore, assuming that the amount of heat flowing into the cryohead is constant, the amount of LHe required to cool and maintain the cryohead at the same temperature will be reduced compared to conventional equipment, and conversely, if the same amount of LHe is supplied to the cryohead , this cryohead is cooled lower than conventional devices.

〔Example〕

In FIG. 1, the solid hydrogen generation device includes a vacuum vessel 1, first and second cryoheads 2.3, a pellet carrier disk 4 in which generated hydrogen pellets are held, and the pellet carrier disk 4 is It basically consists of a cooling means 5 for cooling to a low temperature and a hydrogen gas supply means 6 for supplying hydrogen gas for hydrogen pellets.

A cylindrical cryogenic housing 20 is disposed inside the vacuum vessel 1, and a first cryohead 2 is formed on one end surface of the cryogenic housing 20. This cryogenic housing 20
Inside, a second cryohead 3 is arranged facing the first cryohead 2, and a pellet carrier disk 4 is interposed between the two so as to be rotatable around a horizontal axis. The pair of cryoheads 2.3 and the pellet carrier disk 4 constitute a solid hydrogen generation section.

A downstream end of a cold material supply pipe 51 of the cooling means 5 is connected to the first and second cryoheads 2.3, and an upstream end of this cold material supply pipe 51 is connected to the dewar bottle 52. It is connected to the stored LHe. Also, this dewar bottle 52 is G
This GHe cylinder 5 is connected to the He cylinder 53.
3 and the dewar bottle 52 are configured so that the LHc in the dewar bottle 52 can be pumped to the cryohead 2.3 at a predetermined pressure using this as a pressure source. Further, the cold material supply pipe 51 is provided with an air cylinder 54, and the air cylinder 54 is configured so that the cold material supply pipe 51 is opened and closed by its operation.

The cold material supply pipe 51, the dewar bottle 52, the GHe cylinder 53, and the like constitute a clogging material supply section of the cooling means 5. The first and second cryoheads 2 and 3 are cooled to a predetermined extremely low temperature by LHe supplied by the cold material supply pipe 51.

Furthermore, the upstream ends of exhaust pipes 55a and 55b are connected to the first and second cryoheads 2°3, respectively, and these exhaust pipes 55a and 55b are connected to the hot water tank 5.
6 and this hot water tank 56
Vacuum pumps (exhaust pumps) 57a and 57b are installed on the downstream side of
is provided. And these exhaust pipes 57a, 57b
The downstream end of is connected to a helium recovery pipe (not shown). In the exhaust pipes 55a, 55b, the used LHe in the cryohead 2.3 is forcibly exhausted by the operation of the vacuum pumps 57a, 57b. Further, the hot water tank 56 is heated by the exhaust pipe 55a.
, 55b is configured to completely vaporize helium.

On the other hand, a cooling surface 2 that is in surface contact with the pellet carrier disk 4 is provided on the opposing surfaces of the pair of cryoheads 2 and 3.
1.31 is formed and the pellet carrier disk 4
is cooled by pressing both sides of the pellet carrier disk 4 against the cooling surface 21.31.

A plurality of pellet generation holes (not shown) are formed on the same circular locus in the pellet carrier disk 4, and a plurality of hydrogen gas introduction pipes 61 from the hydrogen gas supply means 6 are led opposite to the pellet generation holes. .

The first cryohead 2 is connected to a plurality of launch tubes 71 through which high-pressure gas is introduced from the high-pressure gas supply means 7, and the second cryohead 3 is connected to a plurality of launch tubes 71 through which hydrogen pellets are introduced into the fusion plasma experimental equipment. The gun barrel 32 of is connected,
The firing tube 71 and the gun barrel 32 are arranged so as to face the hydrogen pellet generating hole by rotating the pellet carrier disk 4.

The pair of cryoheads 2 and 3 are surrounded by a shield casing (not shown), and this shield casing is cooled by liquid nitrogen in a liquid nitrogen supply conduit wrapped around its outer surface.

In the solid hydrogen generator having the above configuration, the first and second
The cryoheads 2 and 3 are supplied with L supplied from the cooling means 5.
The pellet carrier disk 4 is cooled to an extremely low temperature by He, and the cryohead 2.3 cools the pellet carrier disk 4. As a result, the hydrogen gas supplied to the hydrogen pellet generation hole through the hydrogen gas introduction pipe 61 is cooled and solidified, and hydrogen pellets are generated. Next, by rotating the pellet carrier disk 4, the hydrogen pellet generation hole is aligned with the firing tube 71 and the gun barrel 32, and in this state, high pressure gas is introduced from the high pressure gas supply means 7 into the hydrogen pellet generation hole. hydrogen pellets are injected into the gun barrel 32. The hydrogen pellets are then accelerated within the gun barrel 32 and introduced into the plasma.

The LHe in the dewar bottle 52 is the GH in the GHe cylinder 53.
As a result, the LHe is supplied to the cryoheads 2 and 3 at a predetermined pressure through the cold material supply pipe 51.
supplied to The supplied LHe evaporates to cool the cryohead 2゜3 to a predetermined temperature, and a portion of the LHe evaporates.
Hp that has become a state containing e is pumped by vacuum pumps 57a and 57.
By the operation of b, the air is forcibly sucked and exhausted out of the vacuum container 1 through the exhaust pipes 55a and 55b. This He is completely vaporized by passing through the hot water tank 56 and is supplied to a recovery pipe (not shown).

In cooling the cryohead 2.3, after cooling the cryoheads 2 and 3, He is pumped to the vacuum pumps 57a and 57a.
7b, the vacuum pump 57a
, 57b are not provided.
The pressure on the third side can be lowered, and the pressure for pumping LHe from the dewar bottle 52 can be lowered by this lower pressure.

As shown by the solid curve A in Figure 2, which shows the relationship between LHr and its saturated pressure and temperature, the lower the pressure, the lower the saturated temperature. The saturation temperature of LHe decreases accordingly.

As a result of investigating the thermal state quantity of He, curve A shows the relationship between the pressure and temperature T (0K) in the saturated state, and curve B, shown by a dashed line, shows the enthalpy Hin (Hin) of LHe in the saturated state. According to the relationship between Joule/'gram (J/g) and temperature T, and the curve C shown by the two-dot chain line, GHe
('7°K) enthalpy Hout (J/g)
The relationship between T and T is shown.

Here, the heat of vaporization Qin (J/s) of LHr in the cryoheads 2 and 3 is the enthalpy Hin of LHe in the saturated state and the enthalpy Hou of GHe (7°K).
Based on t and the supply flow rate G (g/s) of LHe, Qin= (Hout −Hln) XG−−・・
It is represented by ...-■. In this equation 0, (H
Since the value of (ul-Hin) increases as the temperature decreases, the evaporative heat amount Qin increases as the temperature decreases. Therefore, even if the supply flow rate G of LHe is the same, the amount of heat of evaporation Qin increases as the temperature decreases,
The temperature of cryohead 2.3 becomes lower. Conversely, if the heat of evaporation Qin is kept constant, the temperature will be low (Hou
Since the value of t-Hin) increases, it becomes possible to reduce the LHe supply flow rate G in inverse proportion to this.

Therefore, according to this embodiment, when the LHe supply flow rate is set to be the same, the cryoheads 2 and 3 can be cooled to a lower temperature than in the case of the conventional apparatus shown in FIG. This results in better quality hydrogen pellets and reduces the amount of LHe required to cool the cryohead 2.3 to the same temperature as with conventional equipment, reducing the cost for hydrogen pellet production. be able to.

[Test example]

When LHe is pumped at a pressure of about 1°7 atm to cool cryohead b to a predetermined temperature using the conventional device shown in FIG. 3, the LHe supply flow rate is 18 to 19
//h. Next, when the vacuum pumps 57a and 57b were operated using the embodiment shown in FIG. 1 to achieve the same cooling temperature as the cryoheads 2 and 3 of this conventional device, the pumping pressure was approximately 0. .7 atm, L
The supply flow rate of He was approximately 15 A'/h.

These test results are verified using the formula 0. First, the saturation temperature T1 of LHe when the pressure is 1.7a+m is determined from the curve shown by the solid line in Fig. 2, and Hin at this temperature T1 is calculated.
The values of and Hout are determined from the curves shown by the one-dot chain line and the two-dot chain line. From these values, (
The value of Hoot-Hin) was found to be approximately 32.4. Similarly, when the pressure is 0.7a+m (Hout
-Hin) was approximately 40.9.

Next, the value (32, 4) of (Hoi - Hln) in the case of the conventional device and the supply flow rate value (19) of LHe are set to 0.
Based on the amount of heat of evaporation found by substituting it into the formula, and setting this and the amount of heat of evaporation in the case of the example device to be equal to each other, LHe
If we back-calculate the required supply flow rate of
15) was obtained. Therefore, the above test results and the theoretical values almost match.

In the above embodiment, the vacuum pumps 57a and 57b are used as a means for forced evacuation, but the device is not limited to this, and any device capable of forcibly ejecting He from the cryohead to lower the pressure may be used. For example, an ejector may be used. etc. may also be used.

〔Effect of the invention〕

According to the solid hydrogen generator of the present invention, the LHe pressure at the cryohead is reduced by forced exhaust by the exhaust pump.
The amount of heat of evaporation of LHe can be increased by an amount lower than that in the case of evacuation based on a mere pressure difference from atmospheric pressure in conventional devices.

Therefore, if the amount of heat flowing into the cryohead is constant, the amount of LHe required to cool and maintain the cryohead at the same temperature can be reduced compared to conventional equipment. When the cryohead is supplied to the head, the cryohead can be cooled to a lower temperature than conventional devices, and cooling efficiency can be improved.

Therefore, in producing solid hydrogen, it is possible to produce better quality solid hydrogen and reduce its cost.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, and FIG. 2 is a He
FIG. 3 is an explanatory diagram showing a conventional solid hydrogen generator. 1...Vacuum container, 2.3...Cryotosoto, 4
... Pellet carrier disk, 5 ... Cooling means, 6
. . . Hydrogen gas supply means, 51 . . . Closure supply pipe line, 5
2... Dewar bottle, 53-G He cylinder, 55a
, 55b...exhaust pipe line, 57a, 57b...vacuum pump.

Claims (1)

[Claims] 1. A vacuum container, a solid hydrogen generation section disposed in the vacuum container, a cooling means for cooling the solid hydrogen generation section to an extremely low temperature, and a hydrogen gas supply means for supplying hydrogen gas to the solid hydrogen generation section. In the solid hydrogen generation device, the cooling means includes a cold material supply section that pumps cold material to the solid hydrogen generation section, and a cold material supply section that discharges the cold material after cooling the solid hydrogen generation section to the outside of the vacuum container. 1. A solid hydrogen generation device comprising: a discharge section; the discharge section is provided with an exhaust pump for forcibly exhausting the cold material.