JP2004257475A - Liquefied gas force feed method, hydrogen manufacturing method, and liquefied gas force feed equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquefied gas force feed method capable of easily force-feeding liquefied gas, a hydrogen manufacturing method for controlling increase in the number of steps by using the liquefied gas force feed method, and liquefied gas force feed equipment capable of simplifying the configuration. <P>SOLUTION: In the method in which liquefied gas sealed in a gas cylinder is boosted and fed by at least two pumps disposed in series, liquefied gas is fed to a first pump out of the pumps, and the liquefied gas is preliminarily pressurized by the first pump so that the minimum pressure of the liquefied gas reaches the pressure pmin higher than the saturated vapor pressure PV when sucking the liquefied gas of the second pump disposed on the downstream side of the first pump. Generation of bubbles in the first pump can be easily prevented, and liquefied gas can be reliably and easily fed at the predetermined pressure without using any special method such as a known super-cooling method. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquefied gas pumping method using a plurality of pumps, a hydrogen production method, and a liquefied gas pumping apparatus.
[0002]
[Prior art]
As a liquefied gas pumping device and a liquefied gas pumping method, a device using supercooling means is known (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2002-106789 (page 3-4, FIG. 1)
[0004]
FIG. 1 of Patent Document 1 will be described with reference to FIG. The reference numerals have been re-assigned.
FIG. 4 is a system diagram of a conventional liquefied gas pumping apparatus, and shows liquefied gas pumping equipment in which a liquefied gas container 101, a liquid storage container 102, a pump 103, an evaporator 104, and a high-pressure gas container 105 are connected in this order.
[0005]
The liquid storage container 102 as the supercooling means is a closed container having a heat insulating structure, and includes a liquefied gas inflow path 107 connected to the liquefied gas container 102, a liquid phase portion 108 of the liquid storage container 102, and a suction port of the pump 103. A liquefied gas outflow path 112 connecting the gas reservoir 111, a gas discharge path 114 for discharging gas from the gas phase portion 113 of the liquid reservoir 102, a gas discharge valve 115 provided in the gas discharge path 114, and a gas vent of the pump 103. 117, and a degassing path 118 connected to the degassing path 117.
[0006]
[Problems to be solved by the invention]
In the above-mentioned liquefied gas pumping equipment, since the liquid storage container 102 having many of the above-described structures is required in order to be in a supercooled state, the structure of the equipment is complicated, and the cost is increased.
In addition, it is necessary to precisely control the temperature and pressure of the liquefied gas in order to bring it into a supercooled state, and the process becomes complicated as a liquefied gas pumping method.
[0007]
Furthermore, for example, when this liquefied gas pumping equipment is used for a hydrogen production method, if liquefied gas pumping equipment, a reformer, and a hydrogen separator are provided in this order to obtain hydrogen from liquefied gas, Is complicated, the number of steps in the entire hydrogen production method increases, and productivity decreases.
[0008]
Accordingly, an object of the present invention is to provide a liquefied gas pumping method capable of easily pumping a liquefied gas, a hydrogen production method using the liquefied gas pumping method to suppress an increase in the number of steps, and a liquefied gas pumping apparatus capable of simplifying the configuration. And to provide.
[0009]
[Means for Solving the Problems]
To achieve the above object, a first aspect of the present invention is a method of increasing the pressure of a liquefied gas enclosed in a container by at least two pumps arranged in series and sending out the liquefied gas in a liquid state. Liquefied gas is pre-pressurized by the upstream pump so that the liquefied gas becomes higher than its saturated vapor pressure when the liquefied gas is sucked by the downstream pump arranged downstream of the upstream pump. It is characterized by the following.
[0010]
By pre-pressurizing the liquefied gas to a pressure higher than its saturated vapor pressure when the liquefied gas is sucked by the downstream pump by the upstream pump, it is possible to easily prevent the generation of bubbles in the downstream pump. Thus, the liquefied gas can be easily delivered at a predetermined pressure without using a special method such as conventional supercooling.
[0011]
Claim 2 is a hydrogen production method for producing high-purity hydrogen by generating a reformed gas by a reforming reaction using hydrocarbon as a raw material and selectively separating hydrogen from the reformed gas by a hydrogen separation membrane. The liquefied gas is supplied to the upstream pump in a liquid state so that the liquefied gas composed of hydrocarbons sealed in the container is pressurized and sent out by at least two pumps arranged in series. The liquefaction after the pre-pressurization is performed by pre-pressurizing the liquefied gas to a pressure higher than its saturated vapor pressure at the time of suction of the liquefied gas by the downstream pump arranged downstream of the upstream pump by the pump. It is characterized by obtaining hydrogen using gas as a raw material.
[0012]
By adopting the liquefied gas pumping method as the hydrogen producing method, it is possible to suppress an increase in the number of steps of the hydrogen producing method including the liquefied gas pumping method, and to increase productivity.
[0013]
Claim 3 is a liquefied gas pumping device which pressurizes and sends out a liquefied gas enclosed in a container by at least two pumps arranged in series, wherein the liquefied gas pumping device sucks the liquefied gas in the container. It comprises an upstream pump for increasing the pressure and a downstream pump connected to the downstream side of the upstream pump and increasing the liquefied gas to a predetermined pressure. It is characterized in that the gas is pre-pressurized to a pressure higher than its saturated vapor pressure.
[0014]
The liquefied gas pumping device is composed of an upstream pump and a downstream pump, and liquefied gas is pumped by the liquefied gas pumping device, so that the liquefied gas can be reliably sent as a liquid state at a predetermined pressure with a simple configuration. Can be.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals.
FIG. 1 is a system diagram of a hydrogen production apparatus provided with a liquefied gas pumping apparatus according to the present invention. A hydrogen production apparatus 10 includes a gas cylinder 11 as a container containing a liquefied gas 11a and a liquefied gas pipe extending from the gas cylinder 11. 12; a hydrogen generator 13 connected to the tip of the liquefied gas pipe 12; a back pressure regulator 14 provided in a gas outlet pipe 13a serving as an outlet for gas discharged from the hydrogen generator 13; A liquefied gas flow control valve 15 is provided in the middle of 12, a first pump 16 as an upstream pump, and a second pump 17 as a downstream pump.
The above-described first pump 16 and second pump 17 constitute a liquefied gas pumping device 18.
[0016]
The gas cylinder 11 is configured such that the outlet 21 is located at the lowermost position by inverting the gas cylinder 11 so that the liquid phase 22 faces the outlet 21. Reference numeral 23 denotes a gas phase formed in the gas cylinder 11.
As the liquefied gas, normal butane gas, isobutane gas, propane gas, auto gas, and liquefied natural gas are suitable.
[0017]
The hydrogen generator 13 converts the reforming catalyst layer 26 filled with the reforming catalyst, the hydrogen separation layer 27 disposed inside the reforming catalyst layer 26, and the reforming catalyst in the reforming catalyst layer 26 to a predetermined temperature. Heaters 28, 28 provided outside the reforming catalyst layer 26 to raise the temperature to promote the reforming reaction; a water supply pipe 31 for supplying water to the reforming catalyst layer 26; An air supply pipe 32 for supplying air to the HFC, a gas outlet pipe 13a described above, and a hydrogen recovery pipe 33 for recovering hydrogen from the hydrogen separation layer 27.
[0018]
The reforming catalyst layer 26 has a built-in reforming catalyst, and the raw material gas and water (or raw material gas and air, or the raw material gas, water and air in some cases) while maintaining the reforming catalyst at a high temperature. Supplies hydrogen to cause a reforming reaction, producing hydrogen, carbon dioxide, and trace amounts of carbon monoxide.
[0019]
The hydrogen separation layer 27 separates only hydrogen in the reformed gas formed by reforming in the reforming catalyst layer 26 with the pressure in the reforming catalyst layer 26 through the hydrogen separation membrane. It comprises a hydrogen separation membrane adjacent to the catalyst layer 26 and a chamber formed inside the hydrogen separation membrane.
[0020]
The first pump 16 is a device for pre-pressurizing the liquefied gas and sending it to the first pump 17 so that when the second pump 17 sucks the liquefied gas, the liquefied gas has a pressure higher than its saturated vapor pressure. Press.
[0021]
The second pump 17 is a device that pressurizes the liquefied gas preheated by the first pump 16 in a liquid state to a predetermined pressure and feeds the liquefied gas to the hydrogen generator 13 under pressure.
The back pressure regulator 14 is a device that adjusts a pressure value when pressurized by the second pump 17, that is, a device that adjusts the pressure in the reforming catalyst layer 26 of the hydrogen generator 13.
[0022]
As described above, by using the liquefied gas 11a as a raw material, the hydrogen production apparatus 10 requires a lower pressure in the gas cylinder 11 as compared with, for example, using a high-pressure gas or the like as a raw material, and the gas cylinder 11 can be reduced in size. As a result, handleability can be improved.
[0023]
2 (a) to 2 (c) are explanatory views showing the first and second pumps according to the present invention. FIG. 2 (a) explains the structure, and FIGS. 2 (b) and 2 (c) explain the operation. The first pump 16 and the second pump 17 have the same structure. Hereinafter, the first pump 16 will be described, and the description of the second pump 17 will be omitted.
1A, the first pump 16 is of a diaphragm type, and includes a pump case 36 and a driving unit 37 attached to the pump case 36.
The pump case 36 includes a pump chamber 41, a diaphragm 42 forming a side wall of the pump chamber 41, an inlet valve 43 provided at an inlet of the pump chamber 41, and an outlet valve 44 provided at an outlet of the pump chamber 41. .
[0024]
The diaphragm 42 is an elastic member having a circular cross section.
The inlet valve 43 is a one-way valve, and has an inlet valve case 46 integrally formed with the pump chamber 41, an inlet pipe 47 provided on the gas cylinder 11 (see FIG. 1) side of the inlet valve case 46, and an inlet pipe 47. A ball 48 provided in the inlet valve case 46 so that the inlet valve case 46 can be closed, and a partition wall having through holes 51 provided on the pump chamber 41 side of the inlet valve case 46 (wherein represents a plurality, the same applies hereinafter). 52.
[0025]
The outlet valve 44 is a one-way valve, and includes an outlet valve case 54 integrally formed with the pump chamber 41, an outlet pipe 55 provided on the second pump 17 (see FIG. 1) side of the outlet valve case 54, and an outlet pipe 55. A ball 56 is provided in the outlet valve case 54 so that the valve 55 can be closed, and a partition 58 with through holes 57 provided on the second pump 17 side of the outlet valve case 46.
[0026]
The drive unit 37 accommodates a plunger 61 attached to the diaphragm 42, a flange 62 provided integrally with the plunger 61, a solenoid 63 for sucking the flange 62, and a part of the plunger 61 and the flange 62 so as to be movable. And a drive case 64 containing a solenoid 63.
[0027]
The operation of the first pump 16 described above will now be described.
In (a), when the solenoid 63 is energized and the flange 62 is attracted to the solenoid 63 side, the plunger 61 moves in the axial direction as shown in (b), the diaphragm 42 bends so as to be substantially flat, and the pump The pressure in the pump chamber 41 is increased by reducing the volume of the chamber 41. As a result, the liquefied gas stored in the pump chamber 41 pushes back the ball 56 of the outlet valve 44 and flows to the second pump side through the through holes 57 of the partition wall 58.
[0028]
Next, when the energization of the solenoid is stopped, the diaphragm 42 returns to the original state (state of (a)) as shown in FIG. As a result, the volume of the pump chamber 41 increases, and the pressure in the pump chamber 41 decreases. Therefore, the liquefied gas pushes the ball 48 from the gas cylinder side and flows into the inlet valve 43, and further flows into the pump chamber 41 through the through holes 51 of the partition wall 52.
By intermittently energizing the solenoid described above, the liquefied gas can be continuously delivered.
[0029]
FIG. 3 is a graph showing the pressure generated by the first and second pumps according to the present invention, wherein the vertical axis represents the first pump internal pressure P11, the first pump outlet pressure P12, the second pump internal pressure P21, and the second pump outlet pressure. P22, the horizontal axis represents time T.
The first pump internal pressure P11 and the second pump internal pressure P21 are the pressure in the pump chamber 41 (see FIG. 2) (the pressure at the point A shown in FIG. 2A and the gauge pressure), and the first pump. The outlet pressure P12 and the second pump outlet pressure P22 are the pressures in the outlet valve 44 (the pressure at point B shown in FIG. 2A and the gauge pressure).
[0030]
In FIG. 1, the liquefied gas flow control valve 15 is opened to adjust the flow rate of the liquefied gas to a predetermined flow rate, and the solenoid 63 of the first pump 16 (see FIG. 2A) is energized. Thereby, the liquefied gas flows out to the first pump 16 side due to the pressure of the gas phase 23 in the gas cylinder 11, that is, the vapor pressure of the liquefied gas.
[0031]
In FIG. 3, the first pump internal pressure P11 is an amplitude (p4-p3) with the saturation vapor pressure PV of the liquefied gas (hereinafter simply referred to as "vapor pressure PV") as a median value starting from time t1. The pulse-like change of the cycle dt1 is repeated.
[0032]
Even when the first pump internal pressure P11 becomes lower than the vapor pressure PV, the first pump outlet pressure P12 is isolated from the pump chamber 41 by the ball 56 as shown in FIG. Therefore, in FIG. 3, the pressure does not drop below the vapor pressure PV.
[0033]
Therefore, the first pump outlet pressure P12 rises from the vapor pressure PV to p5 at time t1. This pressure p5 is substantially equal to the pressure p4.
Then, after the first pump outlet pressure P12 rises, the pressure becomes p5 when the first pump internal pressure P11 is p4, and gradually decreases when the first pump internal pressure P11 is p3. The amount of pressure decrease at this time is dr1.
[0034]
First, similarly to the first pump outlet pressure P12, the second pump internal pressure P21 rises from the vapor pressure PV to the pressure p6 starting at the time t1, and maintains the pressure p6 until the time t2. Then, energization of the solenoid of the second pump is started at time t2. As a result, the second pump internal pressure P21 rises from the pressure p6 to the pressure p7 at the time t2, and thereafter, the pulse-like change of the amplitude (p7−pmin) and the cycle dt2 is repeated with the pressure p6 as a central value.
[0035]
At this time, the pressure minimum value pmin of the second pump internal pressure P21 is set to be higher than the vapor pressure PV. That is, by making the second pump pressure P21 higher than the vapor pressure PV of the liquefied gas, it is possible to prevent the liquefied gas from becoming bubbles in the second pump, and to keep the liquefied gas in a liquid state and at a reduced pressure. The supply to the hydrogen generator can be ensured while suppressing the decrease.
[0036]
The second pump outlet pressure P22 rises from the vapor pressure PV to the pressure p8 at time t1, maintains the pressure p8 until time t2, and rises from the pressure p8 to the pressure p9 at time t2. This pressure p9 is substantially equal to the pressure p7.
Thereafter, when the second pump internal pressure P21 is p7, the pressure becomes p9, and when the second pump internal pressure P21 is pmin, the pressure gradually decreases. The amount of pressure drop at this time is dr2.
[0037]
As described above, in the first pump, the outlet pressure P12 is pre-pressurized to the pressure p5, and in the second pump, the outlet pressure is increased to the pressure p9 based on the outlet pressure p5 of the first pump.
[0038]
As described above with reference to FIGS. 1 and 3, the present invention firstly provides a method of sending out a pressurized liquefied gas 11 a enclosed in a gas cylinder 11 by using at least two pumps arranged in series. The liquefied gas 11a is supplied in a liquid state to a first pump 16 of the pumps, and when the liquefied gas is sucked by a second pump 17 arranged downstream of the first pump 16, the liquefied gas 11a Is pre-pressurized to a pressure higher than the saturated vapor pressure PV, that is, a minimum pressure value pmin.
[0039]
The liquefied gas 11a is pre-pressurized by the first pump 16 so that the liquefied gas 11a is at least a pressure pmin higher than the saturated vapor pressure PV at the time of suction of the liquefied gas by the second pump 17, so that the inside of the second pump 17 Can be easily prevented, and the liquefied gas 11a can be easily delivered at a predetermined pressure p9 without using a special method such as conventional supercooling.
[0040]
The second aspect of the present invention is a hydrogen production method in which a reformed gas is produced by a reforming reaction using a hydrocarbon as a raw material, and hydrogen is selectively separated from the reformed gas by a hydrogen separation membrane to produce high-purity hydrogen. In the method, the liquefied gas 11a is supplied to the first pump 16 in a liquid state in order to pump out the liquefied gas 11a composed of hydrocarbon sealed in the gas cylinder 11 by using at least two pumps arranged in series. When the liquefied gas is sucked by the second pump 17 disposed downstream of the first pump 16, the liquefied gas 11a is supplied by the first pump 16 to a pressure pmin which is at least higher than its saturated vapor pressure PV. The pre-pressurization is performed so that hydrogen is obtained from the liquefied gas 11a after the pre-pressurization as a raw material.
By adopting the liquefied gas pumping method as the hydrogen producing method, it is possible to suppress an increase in the number of steps of the hydrogen producing method including the liquefied gas pumping method, and to increase productivity.
[0041]
Thirdly, the present invention relates to a liquefied gas pumping device 18 which pressurizes and sends out a liquefied gas 11a sealed in a gas cylinder 11 with at least two pumps arranged in series. And a second pump 17 connected to the downstream side of the first pump 16 for increasing the pressure of the liquefied gas 11a to a predetermined pressure p9. The pump 16 is characterized in that when the second pump 17 sucks the liquefied gas, the liquefied gas 11a is pre-pressurized so as to have a pressure pmin that is at least the higher than the saturated vapor pressure PV.
[0042]
The liquefied gas pumping device 18 is composed of a first pump 16 and a second pump 17, and the liquefied gas 11a is pumped by the liquefied gas pumping device 18. Can be transmitted reliably.
[0043]
In the present embodiment, the first and second pumps are used as pumps. However, the present invention is not limited to this, and another pump may be used as the first and second pumps according to the pressure setting in the hydrogen generator. Further, they may be connected in series.
[0044]
【The invention's effect】
The present invention has the following effects by the above configuration.
In the liquefied gas pumping method according to the first aspect, the liquefied gas is supplied in a liquid state to an upstream pump of the pumps, and when the liquefied gas is sucked by a downstream pump arranged downstream of the upstream pump by the upstream pump. Since the liquefied gas is pre-pressurized to a pressure higher than its saturated vapor pressure, the generation of bubbles in the downstream pump can be easily prevented, and a special method such as conventional supercooling can be used. It is possible to easily send the liquefied gas at a predetermined pressure without using the gas.
[0045]
In the hydrogen production method according to the second aspect, the liquefied gas is sent to the upstream pump in a liquid state in order to pump out the liquefied gas composed of the hydrocarbon sealed in the container by increasing the pressure by at least two pumps arranged in series. When the liquefied gas is suctioned by a downstream pump arranged downstream of the upstream pump, the liquefied gas is pre-pressurized so that the liquefied gas has a pressure higher than its saturated vapor pressure. Since hydrogen is obtained using the liquefied gas after pre-pressurization as a raw material, by adopting the liquefied gas pumping method as the hydrogen production method, the number of steps in the hydrogen production method including the liquefied gas pumping method is suppressed, and productivity is reduced. Can be enhanced.
[0046]
A liquefied gas pumping device according to claim 3 includes an upstream pump that suctions and raises the liquefied gas in the container, and a downstream pump that is connected to the downstream side of the upstream pump and pressurizes the liquefied gas to a predetermined pressure. The upstream pump pre-pressurizes the liquefied gas to a pressure higher than its saturated vapor pressure when the downstream pump sucks the liquefied gas. The state can be reliably transmitted.
[Brief description of the drawings]
FIG. 1 is a system diagram of a hydrogen production apparatus provided with a liquefied gas pumping device according to the present invention. FIG. 2 is an explanatory view showing first and second pumps according to the present invention. FIG. Graph showing pressure generated by two pumps. [FIG. 4] System diagram of conventional liquefied gas pumping apparatus. [Description of symbols]
11: container (gas cylinder), 11a: liquefied gas, 16: upstream pump (first pump), 17: downstream pump (second pump), 18: liquefied gas pumping device, p9: predetermined pressure, PV: saturation Vapor pressure.

Claims (3)

A method in which a liquefied gas sealed in a container is pressurized and sent by at least two pumps arranged in series,
Supplying the liquefied gas in a liquid state to an upstream pump of the pumps,
A liquefied gas characterized by pre-pressurizing the liquefied gas to a pressure higher than its saturated vapor pressure when the liquefied gas is sucked by a downstream pump arranged downstream of the upstream pump by the upstream pump. Pumping method. A hydrogen production method for producing high-purity hydrogen by generating a reformed gas by a reforming reaction using hydrocarbon as a raw material and selectively separating hydrogen from the reformed gas by a hydrogen separation membrane,
Supplying the liquefied gas in a liquid state to an upstream pump in order to pressurize and send out the liquefied gas composed of the hydrocarbon enclosed in a container by at least two pumps arranged in series; Thus, when the liquefied gas is sucked by the downstream pump disposed downstream of the upstream pump, the liquefied gas is pre-pressurized so as to have a pressure higher than its saturated vapor pressure, whereby the liquefaction after the pre-pressurization is performed. A method for producing hydrogen, comprising obtaining hydrogen from a gas. In a liquefied gas pumping device that pressurizes and sends out liquefied gas enclosed in a container by at least two pumps arranged in series,
The liquefied gas pumping device comprises an upstream pump for sucking and increasing the pressure of the liquefied gas in the container, and a downstream pump connected to the downstream side of the upstream pump and for increasing the pressure of the liquefied gas to a predetermined pressure. A liquefied gas pumping device, wherein the upstream pump pre-pressurizes the liquefied gas to a pressure higher than its saturated vapor pressure when the downstream pump sucks the liquefied gas.

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