JP4792198B2 - Method and apparatus for supplying liquefied petroleum gas and method for replacing liquefied petroleum gas storage means - Google Patents

Description

  The present invention relates to an exchange method for exchanging storage means such as a liquefied petroleum gas (LPG) cylinder. The present invention also relates to an LPG supply apparatus and method for supplying LPG while exchanging LPG storage means. Furthermore, the present invention relates to a fuel cell system using LPG as a raw fuel.

  The fuel cell system has been actively developed as a power generation system or cogeneration system with good energy utilization efficiency.

  A fuel cell is a system that generates electricity by an electrochemical reaction between hydrogen and oxygen. As one of the hydrogen supply methods, there is a method of reforming liquefied petroleum gas (LPG) to obtain a reformed gas that is a hydrogen-containing gas. This method has already been provided with a socially established LPG supply system. This is more advantageous than a method using pure hydrogen.

  In a fuel cell system using LPG as a raw fuel, for example, the reformer reacts LPG with water to mainly decompose it into carbon monoxide and hydrogen, and then reacts most of the carbon monoxide with water in a shift reactor. Then, it is converted into hydrogen and carbon dioxide, and finally a small amount of residual carbon monoxide is reacted with oxygen to form carbon dioxide in a selective oxidation reactor.

  LPG originally contains some sulfur, and the odorant also contains sulfur. Since the sulfur content deteriorates the reforming performance of the reformer, the sulfur content is also removed by a desulfurizer upstream from the reformer.

  Now, generally, in order to use LPG continuously at home, two 50 kg cylinders are prepared, and when the remaining amount of one cylinder becomes small, switching to the other cylinder is performed. Actually, the cylinder is automatically switched when the pressure of the cylinder in use drops below a predetermined pressure.

  For the cylinder switching, an automatic switching type regulator as described in Non-Patent Document 1, pages 24 to 25 is generally used. As shown in FIG. 4, the automatic switching regulator includes two integral switching units (primary regulators that have both an automatic switching function and a primary pressure reducing function) 100 a and 100 b. This switching unit has diaphragms 101a and b and springs 102a and b, respectively. The pressure of the LPG and the force by the spring are applied to the diaphragm, and the valve 104b is forcibly opened (mechanically) by the rod 103 on the cylinder side (right side of the drawing), and the spare cylinder side ( On the left side of the drawing, the diaphragm 101a is pushed up by the pressure of the LPG supplied from the cylinder in use, and the valve 104a is closed (FIG. 4A). When the LPG remaining amount in the cylinder in use becomes small, the LPG pressure in the regulator is lowered, the diaphragm 101a is pushed downward by the spring 102a, the valve 104a is opened, and LPG is also supplied from the spare cylinder. (FIG. 4B).

  Then, the LPG supplier stops forcibly opening the valve (the right side of the paper) with the rod 103b, and forcibly opens the valve (the left side of the paper) with the rod 103a, and replaces the cylinder with the LPG remaining amount being small ( FIG. 4 (c)).

LPG suppliers visited homes, etc. to check the remaining amount of LPG cylinders, and replaced cylinders when necessary.
"Liquefied petroleum gas mechanic lecture text", edited and published by the High Pressure Gas Safety Association, March 8, 2001 Revised version

  As the amount of LPG remaining in the cylinder decreases, the sulfur content contained in the LPG flowing out of the cylinder tends to increase rapidly. FIG. 1 shows that the amount of LPG consumed in a household 50 kg LPG cylinder based on actual measurement values by the inventors (0% means that the cylinder is full, and 100% indicates that the remaining amount of LPG is zero. ) And an example of the correlation between the sulfur concentration contained in the LPG flowing out from the cylinder. The sulfur concentration, which was 2 to 3 ppm by mass, suddenly increases when the cylinder is nearly empty and reaches about 60 ppm by mass.

  On the other hand, while the LPG remains in a liquid state in the cylinder, the pressure in the cylinder is substantially constant, and the pressure in the cylinder suddenly decreases from the point in time when the liquid phase almost disappears and only the gas phase is present. That is, in the conventional switching method using pressure, switching is performed when the consumption amount is almost 100%. Therefore, immediately before the cylinder is switched, the LPG released from the cylinder contained a relatively high concentration of sulfur.

  When LPG discharged from a cylinder is used in equipment such as a gas stove, it can be used without any problem even at a sulfur concentration of about 60 mass ppm, for example, but such a high sulfur concentration LPG is supplied to the fuel cell system. If this is done, the allowable range of the desulfurizer may be exceeded, and the performance of the reformer or fuel cell may be reduced.

An object of the present invention is to prevent the LPG containing a high concentration of sulfur flows out in supplying LPG from LPG storage means, to provide a L PG supplied how you allow this is there.

Another object of the present invention is that the LPG containing a high concentration of sulfur in the fuel cell system to raw fuel of LPG is prevented from flowing, LPG supply how to the fuel cell system capable of this Is to provide.

According to the present invention, in a method for supplying liquefied petroleum gas from replaceable liquefied petroleum gas storage means having a first system and a second system,
The liquefied petroleum gas is supplied from the other storage means without supplying the liquefied petroleum gas from one of the storage means of the first system and the second system. Measuring step;
A step of transmitting a signal when the integrated flow rate exceeds a predetermined value, wherein the predetermined value is a value at which the liquefied petroleum gas consumption of the other storage means is 95% or less;
Using an automatic switch, upon receiving the signal, the liquefied petroleum gas supply from the one storage means is automatically started and the liquefied petroleum gas supply from the other storage means is automatically stopped. A switching step of automatically switching the storage means for supplying the gas; and a step of receiving the signal and replacing the other storage means within a predetermined time , provided that the predetermined time is a liquefied petroleum of the storage means of one system It is a time determined based on a value obtained by dividing a value of 95% or less of the gas filling amount by the assumed maximum liquefied petroleum gas consumption rate.
A method for supplying liquefied petroleum gas having the following is provided.

  According to the present invention, there is provided a liquefied petroleum gas supply method to a fuel cell system, wherein the liquefied petroleum gas is supplied to the fuel cell system by the liquefied petroleum gas supply method.

  In addition, when it is said that LPG is supplied from the storage means, the use device side is stopped depending on the case, and the LPG may not actually flow from the LPG supply device to the use device. If a flow path leading from the LPG storage means to the use device side is formed, it is included in the state of supplying LPG.

  According to the present invention, the LPG storage means can be switched before LPG having a high sulfur concentration flows out. Therefore, LPG having a low sulfur concentration can be continuously supplied to a device to which LPG is supplied.

  Further, according to the present invention, in a fuel cell system using LPG as a raw fuel, it is possible to continuously operate while avoiding adverse effects due to sulfur.

  The present invention can realize the above-described effects with a simple and relatively inexpensive configuration, and is suitable for small-scale facilities such as home use.

  Furthermore, according to the present invention, since the timing of cylinder replacement is notified to the LPG supplier, it is not necessary for the LPG supplier to go around and check the remaining amount of the cylinder.

  Hereinafter, when LPG is supplied to the fuel cell system, the relationship of LPG consumption-sulfur concentration shown in FIG. 1 is established, and when LPG having a sulfur concentration of 10 ppm or more is supplied to the fuel cell system, the fuel cell system Examples of embodiments of the present invention will be described with reference to the drawings on the assumption that there will be an influence, but the present invention is not limited to these.

  For example, the LPG utilization apparatus may be a hydrogen production apparatus that reforms LPG to produce hydrogen. An example of such a utilization device is a small-scale hydrogen station for supplying hydrogen to a vehicle using hydrogen as a fuel.

  Further, FIG. 1 shows a correlation based on actual measurement values for a 50 kg LPG cylinder generally used for home use. Even if the tendency shown in FIG. 1 is recognized, the correlation shown in FIG. 1 is strictly established in all cases. Do not mean. However, the correlation between LPG consumption and effluent sulfur concentration can be determined experimentally according to the assumed situation.

  Furthermore, the allowable sulfur content level is not limited to 10 ppm, but varies depending on the specifications of the equipment on the user side to which LPG is supplied.

[First form (reference form) ]
FIG. 2 shows an embodiment of the LPG supply device. This form is for reference only. This facility has two systems of LPG storage means connected in parallel. In the figure, a solid line connecting the devices indicates an LPG pipe, and a broken line indicates a signal path. The signal path may be wired or wireless.

  As the LPG storage means, exchangeable known storage means such as an LPG container including an LPG cylinder can be appropriately used. The present invention makes it possible to prevent the outflow of LPG having a high sulfur concentration with a simple and relatively inexpensive configuration. Therefore, the present invention is applied to a small-scale system for home use where the storage means is an LPG cylinder of 50 kg or less. It is particularly preferably applied. The two systems of LPG storage means may be, for example, one container each, or may be a container group in which a plurality of containers are connected to each other.

  Here, one 50 kg LPG cylinder is adopted for one system. The 50 kg cylinders 1a and 1b are connected to check valves 2a and 2b, respectively, and the two systems are merged and connected to the microcomputer meter 6. LPG is supplied to the fuel cell system from the outlet of the microcomputer meter.

  Further, a pressure reducing valve 5 is provided as necessary. If necessary, a plurality of pressure reducing valves can be provided to reduce the pressure in multiple stages.

  As the check valve and the pressure reducing valve, known ones that can be used for LPG supply equipment can be appropriately adopted.

The microcomputer meter 6 compares the measuring flow rate such as an integrated flow meter with the measured integrated flow rate and a predetermined value input in advance, and when the integrated flow rate is equal to or greater than a predetermined value (F ¹ ). It also has a transmission means for emitting a signal (S ¹ ). As such a microcomputer meter, a known one can be used. Further, if there is a measuring means and a transmitting means, a microcomputer meter is not necessary.

The transmission controller 21 is an example of a reporting unit that reports at least a unique identification code to an LPG supplier through, for example, a telephone line when receiving the signal S ¹ from a transmission unit or a microcomputer meter. A well-known transmission controller can be used as appropriate.

  A controller-integrated microcomputer meter in which a microcomputer meter and a transmission controller are integrated can also be used. A well-known microcomputer meter can be used.

When an LPG supplier such as an LPG supplier receives the above notification, it replaces the cylinder. An identification code unique to the LPG supply device is notified and received by the computer 7 constituting the LPG supply management system on the LPG supplier side. The LPG supplier holds customer data such as the location of the LPG supply device, the type of cylinder, the number of cylinders per system in the form of a database, etc., and the received identification code and customer data are collated by a computer, etc. , You can easily know the location and number of cylinders to be replaced. In addition, it is possible to know when the cylinder should be replaced from the date and time when the notification is received (the date and time when it is detected that the integrated flow rate is F ¹ or more may be included in the notification itself) and the predetermined time T ¹ . Based on this information, the LPG supplier arranges replacement of the cylinder, and the truck 8 loaded with the full cylinder is directed to the location of the LPG supply facility, and exchanges the used cylinder and the full cylinder.

  Note that the LPG supplier is, for example, an LPG supplier that has a contract with an LPG consumer or user (including agents acting on behalf of at least part of the business).

  Here, LPG is supplied simultaneously from both cylinders to the fuel cell system during normal times (while there is room in the remaining amounts of the cylinders 1a and 1b). When replacing the cylinder, the two cylinders are replaced with a time difference. First, the original valve of the cylinder 1b is closed and removed while the cylinder 1a is allowed to flow out of LPG, a new cylinder 1b is connected and the original valve is opened, and the cylinder 1b side is allowed to discharge LPG. Next, the cylinder 1b is closed and removed while the cylinder 1b is capable of flowing out LPG, a new cylinder 1a is connected and the valve is opened, and the cylinder 1a is allowed to flow out LPG. As a result, the LPG can be supplied to both systems again.

  By such a cylinder replacement method, LPG can be continuously supplied to the fuel cell system side.

The predetermined integrated flow rate value F ¹ is related to the allowable sulfur level of the LPG-using device to which LPG is supplied and a predetermined time (T ¹ ) for cylinder replacement. The predetermined time T ¹ is set as the time required for the replacement work to be completed after the signal S ¹ for replacement is issued.

This will be described with reference to FIG. For example, assuming that LPG having a sulfur concentration of 10 ppm or more is supplied to a user device, the LPG consumption amount giving a sulfur concentration of 10 ppm is calculated (approx. 95% in FIG. 1), and unit time. The maximum LPG consumption that can be consumed at the predetermined time T ¹ is determined from the maximum value of the per LPG consumption and the predetermined time T ¹ for replacement (assuming 10% of the cylinder filling amount). At this time, if a cylinder replacement notification is issued when the LPG consumption reaches 85%, the sulfur concentration can be substantially avoided from reaching 10 ppm.

Since the amount of LPG filled in the new cylinder is known, an amount corresponding to 85% of the filling amount (for two cylinders) is set in the microcomputer meter 6 in advance, and when the integrated flow rate reaches that amount. A signal S ¹ for exchange is generated. When the cylinder replacement work is completed, the integrated flow rate is reset, and the integrated flow rate starts to be counted again.

  In addition, considering the case where the cylinder is not replaced even though there is a report of the cylinder replacement, the microcomputer meter will generate an interlock signal when the integrated flow rate exceeds the amount corresponding to 95% of the LPG consumption. It is also possible to stop the fuel cell system by sending this signal to the fuel cell system.

Assuming that the LPG filling amount of one cylinder is V, the predetermined value of the integrated flow rate for generating a signal for replacement is F ¹ , and the integrated flow rate for generating an interlock signal is F ¹ _int , here, LPG is simultaneously applied from two cylinders. To supply,
F ¹ = 0.85 (2V),
F ¹ _int = 0.95 (2V)
It can be expressed as.

[Second form]
FIG. 3 shows another form of LPG supply equipment. This facility has an automatic switch 30 and can control the automatic switch from a controller 31 with a transmission function. In the above-described embodiment, LPG is supplied to the fuel cell system from the two cylinders at the same time except when the cylinder is replaced. However, in this embodiment, the LPG is automatically switched between the two cylinders while the LPG is switched to the fuel cell system. Supply.

The controller with a transmission function, when receiving the signal S ² for cylinder switching from the transmission means or the microcomputer meter, for example, a reporting means for reporting at least a unique identification code to the LPG supplier through a telephone line, and a signal S ² When received, it also has a function of a control signal transmission means for sending a signal for controlling each automatic shut-off valve. In response to the signal sent from the controller with the transmission function, the actuator provided in the automatic switch operates to switch the opening and closing of the two cylinders. A well-known controller can be used as a controller with a transmission function.

At the beginning of the initial use, the LPG is full in both the cylinders 1a and 1b. First, the automatic switch 30 is opened on the 1a side (closed on the 1b side), and only the cylinder 1a can flow out LPG, and the use of LPG is started. The integrated flow rate is monitored, and when the integrated flow rate exceeds a predetermined value (F ² ), the microcomputer meter 6 issues a signal to open the 1b side of the automatic switch 30 via the controller 31 with a transmission function. (The 1a side is closed). At the same time, at least a unique identification code is reported from the controller 31 with a transmission function to the cylinder supplier. At this time, the integrated flow rate is reset, and the integrated flow rate is newly counted from zero. In this way, only the cylinder 1b can flow out of LPG.

Cylinder supplier that has received the notification is to replace the cylinder 1a in a predetermined time T ^2, since in this case the cylinder 1b may be exchanged cylinder 1a while until slightly remaining from full liquid state, The predetermined time T ² for replacement in the second mode can be longer than the predetermined time T ¹ for replacement in the first mode.

In addition, the predetermined integrated flow rate value F ² for knowing the timing of issuing a signal for switching is set to an amount equivalent to LPG consumption 85% in consideration of the time for cylinder replacement in the first embodiment. In the second embodiment, cylinder switching can be performed automatically and instantaneously and LPG can be continuously supplied, so there is no need to consider the time for cylinder replacement, and the LPG consumption can be equivalent to 95%. it can. That is, in the first embodiment, the cylinder is replaced with the LPG remaining amount being 85%, but in the second embodiment, the cylinder can be used until the LPG remaining amount becomes 95%. At this time, T ² can be determined in consideration of a safety factor based on a value obtained by dividing 95% of the LPG filling amount of one cylinder by the maximum expected LPG consumption rate.

The predetermined value F ² of the integrated flow rate in the second embodiment is
F ² = 0.95V
It can be expressed as.

Only cylinder 1b as described above using the LPG as possible LPG outlet, when the cumulative flow becomes again a predetermined value F ^2, the microcomputer meter 6 emits a signal S ^2, via the transmission function with the controller 31 automatically The 1a side of the switching device 30 is opened (the 1b side is closed). Simultaneously, the controller 31 with transmission function notifies the cylinder supplier, and the monitored integrated flow rate is reset. Thus, only the cylinder 1a can be supplied with LPG again, and the cylinder supplier replaces the cylinder 1b. Thereafter, the cylinders 1a and 1b are switched so that the low-sulfur LPG can always be supplied to the fuel cell system.

When determining the predetermined values F ¹ and F ² of the integrated flow rate and the predetermined times T ¹ and T ² , it is possible to appropriately multiply the safety factor.

[Fuel cell system]
The fuel cell system includes a desulfurizer that desulfurizes supplied LPG, a reformer that reforms the desulfurized LPG to obtain a reformed gas containing hydrogen, a fuel cell that uses the reformed gas as fuel, and the like. A known fuel cell system using LPG as a raw fuel can be used, and the above-described LPG supply device can be attached thereto.

It is a graph which shows an example of the correlation of the consumption of LPG in a LPG cylinder, and the sulfur concentration contained in LPG which flows out from a cylinder. It is a schematic diagram which shows the outline of one form of an LPG supply apparatus. It is a schematic diagram which shows the outline of another form of an LPG supply apparatus. It is typical sectional drawing which shows the conventional automatic switching type regulator which switches cylinders using a pressure.

Explanation of symbols

1a, 1b: LPG cylinder (first system, second system)
2a, 2b: Check valves (first system, second system)
5: pressure reducing valve 6: microcomputer meter 21: transmission controller 30: automatic switch 31: controller with transmission function 100a, 100b: automatic switching regulator 101a, 101b: diaphragm 102a, 102b: spring 103a, 103b: rod 104a, 104b: Valves S ¹ and S ² : Signals issued when the integrated flow rate exceeds a predetermined value

Claims (2)

In a method of supplying liquefied petroleum gas from replaceable liquefied petroleum gas storage means having a first system and a second system,
The liquefied petroleum gas is supplied from the other storage means without supplying the liquefied petroleum gas from one of the storage means of the first system and the second system. Measuring step;
A step of transmitting a signal when the integrated flow rate exceeds a predetermined value, wherein the predetermined value is a value at which the liquefied petroleum gas consumption of the other storage means is 95% or less;
Using an automatic switch, upon receiving the signal, the liquefied petroleum gas supply from the one storage means is automatically started and the liquefied petroleum gas supply from the other storage means is automatically stopped. A switching step of automatically switching the storage means for supplying the gas; and a step of receiving the signal and replacing the other storage means within a predetermined time , provided that the predetermined time is a liquefied petroleum of the storage means of one system It is a time determined based on a value obtained by dividing a value of 95% or less of the gas filling amount by the assumed maximum liquefied petroleum gas consumption rate.
A method for supplying liquefied petroleum gas.   A liquefied petroleum gas supply method to a fuel cell system, characterized in that the liquefied petroleum gas is supplied to the fuel cell system by the liquefied petroleum gas supply method according to claim 1.

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