U.S. patent application number 14/503607 was filed with the patent office on 2016-04-07 for passive anode gas recovery system for fuel cell.
The applicant listed for this patent is NATIONAL UNIVERSITY OF TAINAN. Invention is credited to CHUN-YUAN CHANG, JENN-JIANG HWANG, JENN-KUN KUO, YEN-HSUN LU.
Application Number | 20160099477 14/503607 |
Document ID | / |
Family ID | 55633456 |
Filed Date | 2016-04-07 |
United States Patent
Application |
20160099477 |
Kind Code |
A1 |
HWANG; JENN-JIANG ; et
al. |
April 7, 2016 |
PASSIVE ANODE GAS RECOVERY SYSTEM FOR FUEL CELL
Abstract
A passive anode gas recovery system for fuel cells is revealed.
The system includes a fuel cell, a fuel supply device, an
electronically controlled regulator, a first ejection module, a
second ejection module, a hydrogen recovery module, and a
controller. The system is a passive fuel recovery system disposed
on an outlet end of an anode of the fuel cell. By the controller,
the hydrogen recovery module recovers unconsumed hydrogen gas in
the fuel cell provided by the fuel supply device into two ejection
modules with different orifice diameters for recycling and reuse.
The system has advantages of low cost, no extra energy consumed,
and no external controller required. The system can be applied to
developing fuel cell systems with high efficiency and low cost.
Inventors: |
HWANG; JENN-JIANG; (TAINAN
CITY, TW) ; CHANG; CHUN-YUAN; (TAINAN CITY, TW)
; LU; YEN-HSUN; (TAINAN CITY, TW) ; KUO;
JENN-KUN; (TAINAN CITY, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATIONAL UNIVERSITY OF TAINAN |
TAINAN CITY |
|
TW |
|
|
Family ID: |
55633456 |
Appl. No.: |
14/503607 |
Filed: |
October 1, 2014 |
Current U.S.
Class: |
429/415 |
Current CPC
Class: |
Y02E 60/50 20130101;
H01M 8/04104 20130101; H01M 8/1018 20130101; H01M 8/04097 20130101;
H01M 2008/1095 20130101 |
International
Class: |
H01M 8/04 20060101
H01M008/04; H01M 8/10 20060101 H01M008/10 |
Claims
1. A passive anode gas recovery system for fuel cells disposed on
an anode of a fuel cell for effectively recycling and reuse of
hydrogen gas not reacted comprising: a fuel cell having a fuel
input end and a fuel output end disposed on an anode thereof; a
fuel supply device used for storage of hydrogen gas the fuel cell
required; an electronically controlled regulator that is connected
to the fuel supply device and is used for regulating a pressure of
the hydrogen gas from the fuel supply device and outputting the
hydrogen gas; a first ejection module having a first solenoid
valve, a first ejector and a first hydrogen gas flow meter; one end
of the first ejection module receiving the hydrogen gas that comes
from the fuel supply device and having the pressure regulated by
the electronically controlled regulator; the first solenoid valve
allowing the hydrogen gas entering the first ejector to be
pressured and then the hydrogen gas passing through the other end
of the first ejection module and the fuel input end to be used by
the fuel cell; the first hydrogen gas flow meter connected to the
first ejector for monitoring flow rate of the hydrogen gas output
(by) from the first ejector; a second ejection module connected to
the first ejection module in parallel and including a second
solenoid valve, a second ejector and a second hydrogen gas flow
meter; a hydrogen recovery module that includes a third hydrogen
gas flow meter and a fourth hydrogen gas flow meter; one end of the
third hydrogen gas flow meter and one end of the fourth hydrogen
gas flow meter are connected to the fuel output end of the fuel
cell while the other end of the fourth hydrogen gas flow meter and
the other end of the third hydrogen gas flow meter are respectively
connected to the first ejector and the second ejector for
monitoring flow rate of the hydrogen gas recovered; and a
controller connected to the fuel supply device and used for
receiving parameters output from the first hydrogen gas flow meter,
the second hydrogen gas flow meter, the third hydrogen gas flow
meter, and the fourth hydrogen gas flow meter to judge the hydrogen
gas should be recovered to the first ejector or the second ejector
by the hydrogen recovery module for recycling and reuse; the first
ejector and the second ejector respectively having a plurality of
orifices with different diameters and made from electrochromic
materials; the controller provides proper current for adjustment of
the diameter of the orifice.
2. The system as claimed in claim 1, wherein the fuel cell is a
proton exchange membrane fuel cell (PEMFC).
3. The system as claimed in claim 1, wherein the electronically
controlled regulator is used for regulating a pressure of the
hydrogen gas from the fuel supply device to 1.about.10 bar and the
hydrogen gas is used by the first ejector and the second
ejector.
4. The system as claimed in claim 1, wherein the first ejector and
the second ejector respectively have six orifice diameters each of
which is ranging from 0.5 mm to 2 mm.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Fields of the invention
[0002] The present invention relates to a passive anode gas
recovery system for fuel cells, especially to a passive fuel
recovery system arranged at an outlet end of an anode of a fuel
cell that recovers unconsumed hydrogen gas in the fuel cell for
recycling and reuse. The passive fuel recovery system of the fuel
cell has high efficiency and low cost.
[0003] 2. Descriptions of Related Art
[0004] In order to provide current the load required, hydrogen gas
more than the anode of fuel cells required is supplied. Thus a part
of hydrogen gas unconsumed needs to be exhausted. However, once
being exhausted to the atmosphere, there is a risk of explosion due
to combustion reaction of the hydrogen gas. Thus the residual
hydrogen gas must be recovered during operation of the fuel cell.
In most of the fuel cells available now, active devices such as
pumps are added for recycling of the hydrogen gas. Yet the pump
added consumes more power. An extra controller is required for the
system. This causes increasing of the cost and the volume of the
system is larger. In order to solve the problem mentioned above,
some research uses certain structure such as ejectors for hydrogen
recovery of fuel cells. The two ejectors are connected to form a
large-scale ejector for recycling and reuse of hydrogen gas not
reacted. Yet the recovery efficiency is low due to insufficient
vacuum in the ejector caused by the larger air chamber in the
ejector. In order to overcome these shortcomings, there is a need
to provide a novel recovery system for fuel cells with advantages
of compact volume, light weight and low cost.
SUMMARY OF THE INVENTION
[0005] Therefore it is a primary object of the present invention to
provide a passive anode gas recovery system for fuel cells that
includes a passive fuel recovery system disposed on an outlet end
of an anode of a fuel cell and used for effective recycling and
reuse of unconsumed hydrogen fuel in the fuel cell. In combination
with features of PEMFC that has high energy density and provides
power required along with changes of load power, the recycling
system for fuel cells achieves higher efficiency with lower
cost.
[0006] In order to achieve the above object, the present invention
provides a passive anode gas recovery system for fuel cells in
which a fuel recovery system is arranged at an anode of a fuel cell
and is used for recycling and reusing unconsumed hydrogen fuel in
the fuel cell effectively. The passive anode gas recovery system
for fuel cells includes a fuel cell, a fuel supply device, an
electronically controlled regulator, a first ejection module, a
second ejection module, a hydrogen recovery module, and a
controller. In the fuel cell, a fuel input end and a fuel output
end are disposed on an anode. The fuel supply device is connected
to an electronically controlled regulator and is used for storage
of hydrogen gas the fuel cell required. The pressure of the
hydrogen gas is regulated by the electronically controlled
regulator and then the hydrogen gas is output. The first ejection
module is composed of a first solenoid valve, a first ejector and a
first hydrogen gas flow meter. One end of the first ejection module
is used to receive the hydrogen gas output from the fuel supply
device and with the pressure regulated by the electronically
controlled regulator. The first solenoid valve allows the hydrogen
gas entering the first ejector to be pressured. Then the hydrogen
gas passes through the other end of the first ejection module and
enters the fuel input end to be used by the fuel cell. The first
hydrogen gas flow meter is connected to the first ejector for
monitoring flow rate of the hydrogen gas output from the first
ejector. The second ejection module is connected to the first
ejection module in parallel. The second ejection module is formed
by a second solenoid valve, a second ejector and a second hydrogen
gas flow meter. The hydrogen recovery module includes a third
hydrogen gas flow meter and a fourth hydrogen gas flow meter. One
end of the third hydrogen gas flow meter and one end of the fourth
hydrogen gas flow meter are connected to the fuel output end of the
fuel cell while the other end thereof are respectively connected to
the first ejector and the second ejector for monitoring flow rate
of the recovered hydrogen gas. The controller is connected to the
fuel supply device and used for receiving parameters output from
the first hydrogen gas flow meter, the second hydrogen gas flow
meter, the third hydrogen gas flow meter, and the fourth hydrogen
gas flow meter. According to the parameters received, the system
judges the hydrogen gas should be recovered into the first ejector
or the second ejector by the hydrogen recovery module for recycling
and reuse. The first ejector and the second ejector respectively
have a plurality of orifices having different diameters and made
from electrochromic materials. The controller provides proper
current for adjustment of the orifice diameter.
[0007] The fuel cell is a proton exchange membrane fuel cell
(PEMFC).
[0008] The pressure of the hydrogen gas output from the fuel supply
device is regulated by the electronically controlled regulator to
be ranging from 1 bar to 10 bar. Then the hydrogen gas is used by
the first ejector and the second ejector.
[0009] The first ejector and the second ejector respectively have
orifices with six different diameters ranging from 0.5 mm to 2 mm.
It should be noted that the orifice diameters mentioned above are
only some embodiments of the present invention, not intended to
limit the scope of the present invention. People skilled in the
related art know that the amount of the recovered hydrogen gas of
the fuel cell 1 varies according to the orifice diameter of the
ejector.
[0010] Thereby the passive ejector of the present invention is used
to replace conventional active mechanical pump for hydrogen
recycling and having advantages of low cost, no extra energy
consumption, no external control device required, compact volume,
light weight, maintenance free etc. The present invention can be
applied to developing a fuel cell systems with high efficiency and
low cost. This is beneficial to development of industries such as
fuel cell electric vehicle, fuel cell generator, etc. Moreover, the
ejector compresses hydrogen gas provided to the fuel cell by
potential energy and sucks unused hydrogen gas. Such operation
requires no electricity or energy input of mechanical shaft. Thus
the mass of the equipment is reduced and the reliability is
improved. And the problem of conventional mechanical pump for
hydrogen recycling is solved. Two ejectors are used in the present
invention for hydrogen recovery. Thus the ejectors are easy to be
replaced and the cost can be effectively controlled. Furthermore,
the orifice of the ejector is made from electrochromic material.
The controller supplies proper current for adjustment of the
ejector orifice diameter according to system requirements. The
power range of the fuel cell is adjusted by the changes of the
ejector orifice diameter in real time manner. The wider the
operation range of the power is, the higher the recovery efficiency
the fuel cell has. The conventional ejector has the shortcoming of
poor recovery efficiency. The present invention has precise and
stable supply of hydrogen fuel by potential energy of the high
pressure steel cylinder and the design of hydrogen gas flow meter
to compensate the loss caused by low recovery efficiency of the
ejector. In addition, the system of the present invention features
on quick starting due to the proton exchange membrane fuel cell
with low working temperature used. And the system has advantages of
high reliability, long service life, strong environmental
adaptability and low cost because it has high energy density and
provides power required according to changes of load power.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The structure and the technical means adopted by the present
invention to achieve the above and other objects can be best
understood by referring to the following detailed description of
the preferred embodiments and the accompanying drawings,
wherein
[0012] FIG. 1 is a schematic drawing showing structure of an
embodiment of a passive anode gas recovery system for fuel cells
according to the present invention;
[0013] FIG. 2 is a schematic drawing showing cross section of an
ejector of an embodiment according to the present invention;
[0014] FIG. 3 is a flow chart showing steps of an embodiment
according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Refer to FIG. 1, a schematic drawing showing structure of an
embodiment of a passive anode gas recovery system used for fuel
cells for effective recycling and reuse of hydrogen gas not reacted
according to the present invention is revealed. The passive anode
gas recovery system for fuel cells includes at least one fuel cell
1, a fuel supply device 2, an electronically controlled regulator
3, a first ejection module 4, a second ejection module 5, a
hydrogen recovery module 6, and a controller 7.
[0016] The fuel cell 1 includes a fuel input end 111 and a fuel
output end 112, both disposed on an anode 11 thereof. The fuel cell
1 is a proton exchange membrane fuel cell with features of simple
structure, easy operation, low working temperature, quick starting,
no electrolyte loss, and excellent high current discharge
performance has become the focus of research and development of the
fuel cell 1. Hydrogen gas and oxygen gas are respectively delivered
to the anode 11 and a cathode 12. Hydrogen gas is split into
hydrogen ions and electrons by a catalyst at the anode 11. The
hydrogen ions are passed electrolytes and conducted to the cathode
12 while the electrons travel along an external circuit to the
cathode 12. On a catalyst layer of the cathode 12, oxygen molecules
react with the electrons and protons to form water, which flows out
of the cell along with gas at the cathode 12. Due to low
temperature operation of the PEMFC ranging about 60.about.80 , the
fuel cell starts up quickly. Moreover, PEMFC has high energy
density and provides power required according to changes of load
power. Thus it's a leading candidate for replacement of
conventional chargeable batteries and is applied to vehicles,
buildings or portable devices. Along with the increasing
applications, PEMFC has been developed along with high power, high
reliability, long service life, good environmental adaptation, low
cost, etc. The trend is more obvious in car fuel cells.
[0017] The fuel supply device 2 is connected to an electronically
controlled regulator 3 and is used for storage of hydrogen gas the
fuel cell 1 required. The pressure of the hydrogen gas is regulated
by the electronically controlled regulator 3 and then the hydrogen
gas is output. In a preferred embodiment, a high pressure steel
cylinder is used as the fuel supply device 2. The high pressure
steel cylinder is commonly used to store hydrogen gas. After the
pressure being reduced by the electronically controlled regulator
3, hydrogen gas is directly input into the fuel cell 1. When the
hydrogen gas is delivered into the fuel cell 1, the pressure is
increased a bit to ensure that the hydrogen gas is distributed over
active area of the membrane inside the fuel cell 1. The pressure
should not be too high otherwise flow field plates and the proton
exchange membrane may be damaged. Thus the pressure of the gas is
reduced by the electronically controlled regulator 3 and then the
gas is delivered into the fuel cell 1 to have reactions. As to
hydrogen gas unconsumed, it is recovered by a recovery system.
There is limited volume of hydrogen gas within the high pressure
steel cylinder. Once the hydrogen gas can be recovered, the service
life of the high pressure steel cylinder can be increased.
Moreover, the electronically controlled regulator 3 features on two
micro solenoid valves combined with software and hardware of
driving circuit with multi-pulse width modulation (M-PWM). Pressure
feedback technique is applied to precisely control the pilot
pressure of the designed valve and further control the force that
drives the main valve shaft for regulation of the pressure at the
outlet end of the valve.
[0018] In a preferred embodiment, the pressure of the hydrogen gas
output from the fuel supply device 2 and regulated by the
electronically controlled regulator 3 is ranging from 1 bar to 10
bar and the hydrogen gas is used by the following ejectors.
[0019] The first ejection module 4 consists of a first solenoid
valve 41, a first ejector 42 and a first hydrogen gas flow meter
43. One end of the first ejection module 4 is used to receive the
hydrogen gas output from the fuel supply device 2 and with the
pressure regulated by the electronically controlled regulator 3.
The first solenoid valve 41 allows the hydrogen gas entering the
first ejector 42 to be pressured. Then the hydrogen gas passes
through the other end of the first ejection module 4 and enters the
fuel input end 111 to be used by the fuel cell 1. The first
hydrogen gas flow meter 43 is connected to the first ejector 42 for
monitoring flow rate of the hydrogen gas output from the first
ejector 42. The first ejector 42 can be a Venturi Vacuum Pump. No
extra power is consumed and no additional control system is
required. The ejector has simple structure and many advantages such
as small volume, light weight, no maintenance, and low cost. Thus
the ejector has been applied to industrial fields such as
production and maintenance of vacuum state, low pressure vapor
returning, etc. The ejector is mainly composed of a nozzle, a
venture, a diffuser and a suction chamber. Energy and mass exchange
between working fluid and driven fluid occurs in a mixing chamber.
The speed of the working is decreased while the driven fluid is
increased. The speed of the two kinds of fluid gradually becomes
uniform at an outlet of the mixing chamber. While the mixed fluid
passes through the diffuser, a part of kinetic energy is converted
into pressure. The mixed fluid is output after being pressurized.
The mixed fluid can be vapor phase, liquid phase, or a mixture of
gas and fluid. The medium passed the nozzle is called working
medium. The working medium fluid and the driven medium fluid are
introduced into the mixing chamber for balancing the speed,
generally along with the increasing of the pressure. The pressure
of the fluid flowing from the mixing chamber to the diffuser keeps
increasing. At the outlet of the diffuser, the pressure of the
mixed fluid is larger than the pressure of the driven fluid
entering a receiving chamber. Thus the main function of the ejector
is to increase pressure of the driven fluid without consuming
mechanical energy directly. Refer to FIG. 2, a cross section of the
ejector is revealed. When hydrogen gas flows through an inlet (A)
of the ejector and arrives a narrow nozzle (D), according to Law of
conservation of mass:
{dot over (m)}.sub.A={dot over (m)}.sub.D,
wherein {dot over (m)} is the mass flow rate; and
{dot over (m)}=.rho.AV,
wherein .rho. is the gas density, A is the cross-sectional area,
and V is the average velocity of the fluid; the fluid is considered
as incompressible during the flowing process so that p can be
neglected.
A.sub.AV.sub.A=A.sub.DV.sub.D,
wherein A.sub.A>>A.sub.D because the diameter of the nozzle
(D) is much more smaller than the diameter of the inlet (A);
thus
V.sub.D>>V.sub.A,
according to Bernoulli's Principle:
P.sub.A+1/2.rho.V.sub.A+.rho.gh.sub.A=P.sub.D+1/2.rho.V.sub.D+.rho.gh.su-
b.D,
wherein P is the pressure, g is the gravity, h is the height; the
inlet (A) and the nozzle (D) are considered at the same horizontal
level so that h.sub.A=h.sub.D,
P.sub.A+1/2.rho.V.sub.A=P.sub.D+1/2.rho.V.sub.D,
thus P.sub.A>>P.sub.D, wherein P.sub.A is the input pressure;
.when the fluid flows to the nozzle (D), the pressure generated
P.sub.D is much smaller than the input pressure P.sub.A. The gas
moves form high pressure area to low pressure area. Thus a suction
force is generated at a suction inlet (C) when P.sub.D is smaller
than a fixed value so as to recover the hydrogen gas to the
ejector. Moreover, the suction force the ejector generated enables
hydrogen gas to carry water out. Then the water is removed by
liquid gas separation.
[0020] The second ejection module 5 is connected to the first
ejection module 4 in parallel. The second ejection module 5 is
formed by a second solenoid valve 51, a second ejector 52 and a
second hydrogen gas flow meter 53. The orifice diameter of the
first ejector 42 and the second ejector 52 is ranging from 0.5 mm
to 2 mm. In a preferred embodiment of the present invention, six
ejectors with the orifice diameter of 0.5 mm, 0.7 mm, 1 mm, 1.3 mm,
1.5 mm, and 2 mm respectively are used for compressing hydrogen
gas. The ejectors with the orifice diameter of 0.5 mm and 0.7 mm
are small-orifice-diameter ejectors. In case of smaller orifice
diameter, the ejector has smaller flow rate compared with other
ejectors. Thus the corresponding power/watt is also limited. This
is the shortcoming of ejectors with smaller orifice diameter. Yet
the recovery flow rate of the small-orifice-diameter ejector is
larger than the inlet flow rate. The small-orifice-diameter ejector
has higher recovery efficiency. Moreover, the ejectors with orifice
diameter of 1 mm, 1.3 mm, 1.5 mm, and 2 mm are
large-orifice-diameter ejectors. Thus the corresponding flow rate
is larger and the power is increased and having larger wattage
range. But compared with ejectors with small orifice diameter, the
large-orifice-diameter ejectors have lower recovery flow rate and
poor recovery efficiency. It should be noted that the orifice
diameters mentioned above are only some embodiments of the present
invention, not intended to limit the scope of the present
invention. People skilled in the related art know that the amount
of the recovered hydrogen gas of the fuel cell 1 varies according
to the orifice diameter of the ejector.
[0021] The hydrogen recovery module 6 includes a third hydrogen gas
flow meter 61 and a fourth hydrogen gas flow meter 62. One end of
the third hydrogen gas flow meter 61 and one end of the fourth
hydrogen gas flow meter 62 are connected to the fuel output end 112
of the fuel cell 1 while the other end thereof are respectively
connected to the first ejector 42 and the second ejector 52 for
monitoring flow rate of the recovered hydrogen gas.
[0022] The controller 7 is connected to the fuel supply device 2
and used for receiving parameters output from the first hydrogen
gas flow meter 43, the second hydrogen gas flow meter 53, the third
hydrogen gas flow meter 61, and the fourth hydrogen gas flow meter
62. According to the parameters received, the system checks that
the hydrogen gas should be recovered to the first ejector 42 or the
second ejector 52 by the hydrogen recovery module for recycling and
reuse. The first ejector 42 and the second ejector 52 respectively
have a plurality of orifices having different diameters and made
from electrochromic materials. The controller 7 provides proper
current for adjustment of the orifice diameter.
[0023] In the present invention, a fuel recovery system is disposed
on the anode 11 of the fuel cell 1 by experimental design method
and related experiments are carried out. LabVIEW graphical
programming platform is used for system control and measuring
experiment data. Then CFD-RC simulated software based on the
multi-step finite volume method is used to carry out multi-physics
coupling simulation according to structure and environment of the
experiment system. The Mathematical Model and system control method
related to the recovery mechanism are further discussed. At last,
design and develop an ideal passive recovery system according to
the fuel recovery efficiency the PEMFC required. And the recovery
system is integrated into the fuel cell 1 to form a complete system
of the fuel cell 1. Due to complicated structure, expensive
instrument, and risk of the hydrogen system, hydrogen gas is
replaced by air the in beginning of the research to construct a gas
recovery system for the fuel cell 1. Next the relation between air
flow rate and flow rate of hydrogen gas is calculated by Reynolds
number formula. Thus the performance of hydrogen gas in the ejector
recovery system can be learned.
[0024] Refer to FIG. 3, a flow chart showing steps of an embodiment
of the present invention is disclosed.
[0025] A. Reading Data and Simulating Requirement:
[0026] The fuel cell 1 reads data used and generates
satisfaction-power figure (S-P figure) to simulate the amount of
hydrogen gas the fuel cell 1 required.
[0027] B. Adjusting Pressure:
[0028] The fuel cell 1 sends a command to the electronically
controlled regulator 3 for pressure adjustment. A
Proportional-Integral-Derivative (PID) controller is used to reach
a reference value of S-P figure. PID controller is a control loop
feedback mechanism widely used in industrial control system. The
data collected is compared with a reference value by the PID
controller. Then a difference therebetween is used to calculate a
new input value. The new input value is used to make the data of
the system reach or maintain at the reference value. PID controller
can adjust the input value based on historical data and occurrence
frequency of the difference so as to make the system work/operate
more precisely and stably.
[0029] C. Checking On/Off State of the Ejection Module:
[0030] The first solenoid valve 41 disposed on the first ejection
module 4 controls whether the hydrogen gas enters the first
ejection module 4 or not. There are four combinations when the
first solenoid valve 41 disposed on the first ejection module 4 is
used together with the second solenoid valve 51 of the second
ejection module 5. The first combination is that both solenoid
valves 41, 51 are off. In the second combination, both solenoid
valves 41, 51 are on. In the third combination, the first solenoid
valve 41 is off while the second solenoid valve 51 is on. In the
fourth combination, the first solenoid valve 41 is on while the
second solenoid valve 51 is off.
[0031] D. Reading Equivalent Number:
[0032] Read the equivalent number of the fuel cell 1. The
equivalent number is divided by the value of 2. When the equivalent
number is smaller than 2, the first solenoid valve 41 is off while
the second solenoid valve 51 is on. And the system uses the second
ejection module 5 with larger orifice diameter and worse recovery
efficiency as the main device to recover hydrogen gas. When the
equivalent number is larger than 2, the first solenoid valve 41 is
pulsed while the second solenoid valve 51 is on. The system
activates the first ejection module 4 having smaller orifice
diameter for hydrogen recovery and having higher recovery
efficiency.
[0033] E. Adjusting Wattage:
[0034] The pressure is adjusted by electrically-controlled
regulator 3. Use PID program to make the pressure become consistent
with the reference value of S-P figure.
[0035] F. Reading Information and Storing Data:
[0036] Read program flow by all sensors. If there is a problem, the
program turns the flow back to the process B, the step of adjusting
pressure. The pressure is regulated by the
electronically-controlled regulator 3 and the reference value of
the S-P figure is reached by the PID controller. Once the sensors
check that there is no problem, record and store data related. The
recovery of hydrogen gas is completed.
[0037] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details, and
representative devices shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *