U.S. patent application number 11/061739 was filed with the patent office on 2006-08-24 for fuel cell system comprising modular design features.
Invention is credited to Dingrong Bai, Jean-Guy Chouinard, David Elkaim.
Application Number | 20060188763 11/061739 |
Document ID | / |
Family ID | 36913085 |
Filed Date | 2006-08-24 |
United States Patent
Application |
20060188763 |
Kind Code |
A1 |
Bai; Dingrong ; et
al. |
August 24, 2006 |
Fuel cell system comprising modular design features
Abstract
There is described a fuel cell power system including a fuel
processor subsystem, a fuel cell subsystem, and a power
conditioning subsystem. The fuel processor subsystem comprises a
main module for producing hydrogen rich streams from a hydrocarbon
fuel, a balance of plant module for auxiliary components, and a
control and electronic module for monitoring and controlling the
fuel processor subsystem. The fuel cell subsystem comprises a main
module for generation of electric power and thermal energy from
hydrogen rich streams produced by the fuel processor module and
air, a balance of plant module for auxiliary components, and a
control and electronic module for monitoring and controlling the
fuel cell subsystem. Each module has individual components attached
thereto, the modules being designed and manufactured separately and
assembled together to form the respective subsystems.
Inventors: |
Bai; Dingrong; (Dorval,
CA) ; Chouinard; Jean-Guy; (Ville St-Laurent, CA)
; Elkaim; David; (Ville St-Laurent, CA) |
Correspondence
Address: |
OGILVY RENAULT LLP
1981 MCGILL COLLEGE AVENUE
SUITE 1600
MONTREAL
QC
H3A2Y3
CA
|
Family ID: |
36913085 |
Appl. No.: |
11/061739 |
Filed: |
February 22, 2005 |
Current U.S.
Class: |
429/413 ;
429/425; 429/440; 429/470; 429/511; 429/900 |
Current CPC
Class: |
H01M 8/04052 20130101;
H01M 8/04074 20130101; Y02E 60/50 20130101; H01M 8/247 20130101;
H01M 8/0612 20130101; H01M 8/0625 20130101 |
Class at
Publication: |
429/022 ;
429/019; 429/023; 429/026; 429/037 |
International
Class: |
H01M 8/04 20060101
H01M008/04; H01M 8/06 20060101 H01M008/06; H01M 8/02 20060101
H01M008/02 |
Claims
1. A fuel cell power system including a fuel processor subsystem, a
fuel cell subsystem, and a power conditioning subsystem,
characterized in that: said fuel processor subsystem comprises a
main module for producing hydrogen rich streams from a hydrocarbon
fuel, a balance of plant module for auxiliary components, and a
control and electronic module for monitoring and controlling said
fuel processor subsystem; and said fuel cell subsystem comprises a
main module for generation of electric power and thermal energy
from hydrogen rich streams produced by said fuel processor module
and air, a balance of plant module for auxiliary components, and a
control and electronic module for monitoring and controlling said
fuel cell subsystem; each said module having individual components
attached thereto, said modules being designed and manufactured
separately and assembled together to form the respective
subsystems.
2. The system as claimed in claim 1, wherein said power
conditioning subsystem comprises a control and electronic subsystem
module for monitoring and controlling said power conditioning
subsystem, and a main module for converting DC power generated by
said fuel cell subsystem into regulated DC and/or AC power.
3. The system as claimed in claim 1, wherein said control and
electronic module is composed of an electrical module for hardware
components and a control module for software components.
4. The system as claimed in claim 1, further comprising a heat
recovery subsystem.
5. The system as claimed in claim 4, wherein said heat recovery
subsystem is comprised of a main module for recovering thermal
energy from said fuel processor subsystem and said fuel cell
subsystem and supplying the recovered thermal energy to meet
thermal energy demand, a balance of plant module for auxiliary
components, and a control and electronic module for monitoring and
controlling said heat recovery subsystem.
6. The system as claimed in claim 5, wherein said heat recovery
subsystem also comprises a heat storage module for storing heat
recovered by said heat recovery subsystem, and a supplementary heat
production module to supply heat demands that are beyond the
thermal production capacity of said system.
7. The system as claimed in claim 1, wherein said components on
said balance of plant modules are arranged in a two-dimensional
fashion.
8. The system as claimed in claim 7, wherein said components are
connected by flexible tubing.
9. The system as claimed in claim 1, wherein said fuel cell
subsystem is a stack assembly of plates mechanically clamped
together.
10. The system as claimed in claim 9, wherein all said plates in
said stack assembly have a same cross-section.
11. The system as claimed in claim 10, wherein said stack assembly
comprises of assemblies of plates for heat exchangers and
humidifiers mechanically clamped together.
12. A fuel cell power system including a fuel processor module, a
fuel cell module, and a power conditioning module, characterized in
that: a balance of plant module regroups all system balance of
plant components and is separate from said fuel processor module,
fuel cell module, and power conditioning module; and an electrical
and control module regroups all electrical and control devices to
control and operate said system and is separate from said fuel
processor module, fuel cell module, and power conditioning
module.
13. The system as claimed in claim 12, wherein said fuel cell
module and said fuel processor module are combined and integrated
into one subsystem.
14. The system as claimed in claim 12, further comprising a heat
recovery module.
15. The system as claimed in claim 12, wherein said fuel cell
module is a stack assembly of plates mechanically clamped
together.
16. The system as claimed in claim 15, wherein all said plates in
said stack assembly have a same cross-section.
17. The system as claimed in claim 16, wherein said stack assembly
comprises of assemblies of plates for heat exchangers and
humidifiers mechanically clamped together.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is related to commonly assigned
pending U.S. patent application entitled "Integrated Fuel Cell
Power Module", filed on Sep. 24, 2004 and bearing Ser. No.
10/948,794, the content of which is hereby incorporated by
reference.
TECHNICAL FIELD
[0002] The present invention relates to devices which produce an
electrical current by means of a chemical reaction or change in
physical state, and more specifically, electrochemical fuel cell
power generation systems comprising multiple subsystems including
fuel processing, fuel cell stack, power conditioning, electronics
and controls as well as the components of balance of plant.
BACKGROUND OF THE INVENTION
[0003] Fuel Cells (FC's) are electrochemical devices that directly
convert the chemical energy of a fuel into electricity. In contrast
to energy storage batteries, fuel cells operate continuously as
long as they are provided with reactant gases. In the case of
hydrogen/oxygen fuel cells such as proton exchange membrane fuel
cells, which are the focus of most research activities today, the
only by-product is water and heat if pure hydrogen is used. The
high efficiency of fuel cells and the prospects of generating
electricity without pollution have made them a serious candidate to
power the next generation of vehicles, houses and mobile devices.
More recently, focus of fuel cell development has extended to
remote power supply and applications, in which the current battery
technology reduces availability because of high recharging times
compared to a short period of power supply (e.g. cellular
phones).
[0004] There are basically three major applications of fuel cells,
namely, transportation, stationary and portable powers. In the case
of transportation applications, pure hydrogen appears to be the
most desirable fuel rather than on-board hydrogen production from
hydrocarbon fuels, given the factors such as complexity, cost and
slow start-up. This suggests that a fuel cell power system without
fuel processing is most appropriate for transportation
applications. In the case of stationary applications, especially in
the low power range (<10 kW), two types of application, i.e.
residential and backup power (or uninterruptible power units) are
typical, with the former being generally installed with both a fuel
processor and a fuel cell power system, and the latter only a fuel
cell power system. Depending on the applications, fuel cell
manufacturers have been putting their resources on either
transportation, residential or backup. The products developed and
manufactured in such cases cannot be transferable, i.e. each
product requires a separate, lengthy and costly process of
development, manufacturing and assembly.
[0005] Still, one of the most important issues impeding the
commercialization of fuel cells is the cost. Besides the material,
the complexity in the present designs shares a significant portion
of the high cost. As it is well known in the field, a fuel cell
power plant commonly comprises of hundreds (if not thousands) of
components, with all of these components being properly connected,
integrated, and housed in a chamber. It is a common feature that
these multiple components have been made to best utilize the space
inside the chamber in order to make the fuel cell system more
compact. However, this feature has led to poor manufacturability,
poor accessibility for assembling and poor serviceability. It is
often the case that the whole system or subsystem (such as fuel
processor, fuel cell stack) must be replaced even though there is
only one part that has actually failed.
SUMMARY OF THE INVENTION
[0006] It is therefore an objective of the present invention to
provide a fuel cell system and a method to design and manufacture
the same.
[0007] According to the present invention, the fuel cell system
will be suitable as a stand-alone product for hydrogen production,
pure hydrogen based transportation and backup power systems and
fossil fuel residential applications as a result of disclosed
modular design features. The functionally grouped and mechanically
integrated modules can be separately manufactured, and serviced.
Once manufactured, these modules can be easily installed and
integrated to form a fuel processor, a fuel cell backup power
system, or a residential fuel cell combined heat and power system.
It provides the great degree of flexibility in manufacturing,
assembly, and service. Each module can be easily replaced once it
fails without sacrificing the entire system.
[0008] While this invention will be discussed mostly in relation to
a Proton Exchange Membrane Fuel Cells (PEMFC), operated at either
commonly referred low-temperature (e.g. <100.degree. C.) or
high-temperature (e.g. 120-250.degree. C.) conditions, it is also
applicable to other types of fuel cells such as alkaline fuel cell
(AFC), phosphoric acid fuel cell (PAFC), molten carbonate fuel cell
(MCFC), and solid oxide fuel cell (SOFC).
[0009] The present invention discloses a fuel cell system that is
comprised of functionally grouped and mechanically integrated
modules at all levels of system, subsystem and components, with the
objective to increase the manufacturability, assembling ability and
serviceability. Another objective is to increase the simplicity,
and compactness of fuel cell systems. Yet another objective is to
reduce the costs associated with fuel cell manufacturing, assembly,
maintenance and service. Still another objective is to provide a
method that allows quick development of various fuel cell products,
e.g. fossil fuel residential or stationary CHP units, direct
hydrogen fueled backup power units, and hydrogen production fuel
processor.
[0010] The fuel cell power generation system is an integrated
package from some or all of four major subsystems including fuel
process subsystem, fuel cell subsystem, power conditioning
subsystem and heat recovery subsystem. Furthermore, the fuel
processor subsystem consists of three modules: fuel processor
module, balance of plant module and electronics and controls
module. Similarly, the fuel cell subsystem is made of three
modules: fuel cell module, balance of plant module and electronics
and controls module. The fuel processor module and fuel cell module
each contain several separately manufactured and serviceable
component modules, which are appropriately integrated. Linkage
between the modules can be flexible and/or quick-connectable type.
All the modules from component, subsystem to system are designed
and constructed separately, and once manufactured they are linked
or somehow stacked together according to the flow scheme to form an
integrated compact device. The modular design feature as presented
in this invention allows ease of manufacturing, leak testing,
assembling and maintenance. It also allows repairing or replacing
individual modules easily and cost effectively, once a failure has
been detected.
[0011] In accordance with the present invention, there is provided
a fuel cell power system including a fuel processor subsystem, a
fuel cell subsystem, and a power conditioning subsystem. The fuel
processor subsystem comprises a main module for producing hydrogen
rich streams from a hydrocarbon fuel, a balance of plant module for
auxiliary components, and a control and electronic module for
monitoring and controlling the fuel processor subsystem. The fuel
cell subsystem comprises a main module for generation of electric
power and thermal energy from hydrogen rich streams produced by the
fuel processor module and air, a balance of plant module for
auxiliary components, and a control and electronic module for
monitoring and controlling the fuel cell subsystem. Each module has
individual components attached thereto, the modules being designed
and manufactured separately and assembled together to form the
respective subsystems.
[0012] In accordance with a second broad aspect of the present
invention, there is provided a fuel cell power system including a
fuel processor module, a fuel cell module, and a power conditioning
module, wherein a balance of plant module regroups all system
balance of plant components and is separate from the fuel processor
module, fuel cell module, and power conditioning module; and an
electrical and control module regroups all electrical and control
devices to control and operate the system and is separate from the
fuel processor module, fuel cell module, and power conditioning
module.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Further features and advantages of the present invention
will become apparent from the following detailed description, taken
in combination with the appended drawings, in which:
[0014] FIG. 1. is a block diagram of the fuel cell power generation
system in accordance with a preferred embodiment of the present
invention;
[0015] FIG. 2a illustrates the separate modules that make up the
fuel processor subsystem in accordance with a preferred embodiment
of the present invention;
[0016] FIG. 2b illustrates the separate modules that make up the
fuel processor subsystem in accordance with another preferred
embodiment of the present invention;
[0017] FIG. 3a illustrates the separate modules that make up the
fuel cell subsystem in accordance with a preferred embodiment of
the present invention;
[0018] FIG. 3b illustrates the separate modules that make up the
fuel cell subsystem in accordance with another preferred embodiment
of the present invention;
[0019] FIG. 4 illustrates the separate modules that make up the
power conditioning subsystem in accordance with a preferred
embodiment of the present invention;
[0020] FIG. 5 illustrates the separate modules that make up the
heat recovery subsystem in accordance with a preferred embodiment
of the present invention;
[0021] FIG. 6 illustrates the modular design at the component level
for the fuel processor subsystem in accordance with a preferred
embodiment of the present invention;
[0022] FIG. 7 illustrates the modular design at the component level
for the fuel cell subsystem in accordance with a preferred
embodiment of the present invention; and
[0023] FIG. 8. is a block diagram of the fuel cell power generation
system for a high-temperature system in accordance with a preferred
embodiment of the present invention.
[0024] It will be noted that throughout the appended drawings, like
features are identified by like reference numerals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] FIG. 1 shows a fuel cell power system 10 comprising of four
major subsystems, namely, a fuel processor subsystem (FPS) 20, a
fuel cell subsystem (FCS) 30, a power conditioning subsystem (PCS)
40 and a heat recovery subsystem (HRS) 50. If designed and
manufactured separately, FPS 20, FCS 30 and PCS 40 can be
independent devices for hydrogen production and pure hydrogen based
fuel cell power generators. When combined in a way such as shown in
FIG. 1, it becomes an integrated fossil fuel based fuel cell power
system for either small or large stationary applications. When they
are further integrated with HRS 50, it can provide both heat and
power for users. This provides a modular design at the system
level.
[0026] For the fuel processor subsystem module, as schematically
illustrated in FIG. 2a and FIG. 2b, it further consists of four
general sub-modules, namely, [0027] a fuel processor module 21, in
which all fuel processor sub-components such as steam reformer,
shift reactor, desulfurizer, preferential oxidation reactor (PROX)
and heat exchangers are independently manufactured, and
interconnected according to the fuel processing flow and thermal
management in a preferably compact fashion; [0028] a fuel processor
balance of plant module 22, which is a platform on which all the
auxiliary components in relation to the fuel processing, such as
hand valves, solenoid valves, pressure regulators, check valves,
compressors, flowmeters, and filters, are installed and connected.
There are also connecting ports in predetermined locations for
quick connections of streams from the supply sources and to the
above mentioned fuel processor module 21; [0029] an electrical
module 23, which controls and coordinates the fuel processor
operation by collectively installed all electrical devices such as
I/O boards; [0030] a control module 24, which monitors and controls
the fuel processing subsystem operation, including data acquisition
and display (GUI).
[0031] On FPS 20a, there is a fuel stream 100 supplying the fuel
(e.g. natural gas, liquefied petroleum gas), and a water stream 300
for use in hydrocarbon reforming. Air 200 is shown here only for
illustration purposes because it will actually be taken from
surrounding space. There is another stream, anode off gas recycling
stream 190, which supplies the majority of burning fuel for the
fuel processor in the case that the fuel processor is part of the
fuel cell power system. In the case of stand-alone, this stream
will be compensated by a burning fuel stream which is generally the
same as, and will be split within the fuel processor balance of
plant module 22 from, fuel 100 supplied to the reformer. In case of
cogeneration applications, the cogeneration water 360 from HRS 50
can be supplied to the FPS 20 to recover the available heat from
combustion flue gases. All incoming fluid streams (100, 200, 360,
190, 300) and exhausting streams (hydrogen rich reformate stream
180, flue gas 240, warm cogeneration water 370, and water
condensate 600) are connected to and from the ports on fuel
processor balance of plant module 22 of FPS 20a. Fluids are fluidly
communicating between fuel processor module 21 and balance of plant
module 22 by means of quick connectable, either rigid or flexible
tubes between ports 21a and 22a (i.e. hydrocarbon fuel 101, anode
off gas 191, air 201, cogeneration water 361, deionized water 301,
reformate 179, flue gas 239, warm cogeneration water 369, water
condensate 599). The electric power 430, preferred as DC power,
used to operate the electrical components collectively installed on
electrical module 23 and controllers 24 of FPS 20 can be either
supplied from an external power source (FPS stand-alone) or from
the PCS 40 that converts and conditions the DC power output from
the fuel cell stack (FPS integrated with FCS and PCS). Part of the
electrical power 432 is supplied to operate the fuel processor
balance of plant components on 22 that require electrical power
such as solenoid valves, air blowers, compressors, and electrical
heaters. And the rest of electrical power 431 is supplied to fuel
processor control module, which may receive a control signal 500
from, and send a control signal 505 to the central control system
of fuel cell system 10. The control signals 501 and 504 can be
passed between fuel processor control module 24 and fuel processor
electrical module 23, and signals 503 and 504 can be passed between
fuel processor electrical module 23 and fuel processor balance of
plant module 22.
[0032] FIG. 2b illustrates an alternative to FIG. 2a, in which the
exhausting streams are directly connected from fuel processor
module 21 of FPS 20b. This may be advantageous over 20a, because
the fluid communication between fuel processor module 21 and fuel
processor balance of plant module 22 can be simpler.
[0033] The produced hydrogen rich gas 180 can be used in any way,
or directly supplied to a fuel cell power subsystem 30 (30a or
30b). As for FPS 20, the FCS 30 can also be made up of four
independently manufactured sub-modules, namely, [0034] a fuel cell
module 31, which is an entirely integrated compact assembly
including at lease one fuel cell stack, at least one fuel cell heat
exchanger, a fuel cell stack cooling loop with a coolant expansion
tank and a coolant filter, at least one cathode blower, and
necessary water condensate drainage valves. All these components
are mechanically manufactured and integrated in a preferred compact
fashion; [0035] a fuel cell balance of plant module 32, which is a
mechanical platform on which all necessary auxiliary components
(such as valves, regulators, pumps, etc.) to make the fuel cell
module operable and functional are collectively installed. There
are also connecting ports in predetermined locations for quick
connections of streams from the supply sources and to the fuel cell
module 31; [0036] a fuel cell electrical module 33, a mechanical
platform where all electrical and control devices such as power
supplies, switches, delays, and I/O boards, are collectively
installed, and [0037] a fuel cell control module 34, which monitors
and controls the fuel cell subsystem operation, including data
acquisition and display (GUI).
[0038] In case of direct hydrogen systems, the stream 180 can be
replaced by a pure hydrogen source. Again, an air stream 250 to
cathode of the fuel cell stack is shown here only for illustration
purpose. The water stream 370, flowing from either the FPS 20 or
directly from HRS 50, enters the FCS 30 to remove the heat produced
by the electrochemical reactions of fuel cells. The incoming fluid
streams 180, 250 and 370 are supplied to fuel cell subsystem 30 by
means of quick connectable, rigid of flexible, tubes to ports on
fuel cell balance of plant module 32, from where they are sent to
fuel cell module 31 by collecting either rigid or flexible tubes
181, 251, and 371 between ports 31a and 32a. A stack coolant
stream, 700 and 701, may flow between fuel cell module 31 and fuel
cell balance of plant module 32. The residue fuel 182 flowing out
the fuel cell stack 31 is sent to fuel cell balance of plant module
32, from where it can be discharged or recycled to fuel processor
subsystem 20 as anode off gas stream 190. The fuel cell module
generally includes a fuel cell stack having a plurality of fuel
cells, at least one heat exchanger to transfer fuel cell produced
heat to cogeneration water, and possibly humidifiers for
humidifying fuel stream and/or cathode air. The fuel cell balance
of plant module generally includes all components such as air
blowers, pumps, filters, and solenoid valves necessary for
operating fuel cell system. The warmed water 380, which connects to
stream 379 from fuel cell module 31, flows out the fuel cell
balance of plant module 32 of FCS 30 and returns to HRS 50 while
useful heat can be utilized in any appropriate way by, for
instance, flowing water streams 350 and 390. On the FCS 30, there
is still another output port for discharging a water condensate
stream 601 that may be produced in fuel cell module 31 and flows as
stream 602. The DC power 400 produced is generally subject to a
converter and power conditioner PCS 40. The electric power 420 used
to operate the electronics collectively installed on fuel cell
electrical module 33 and controllers collectively installed on fuel
cell control module 34 of FCS 30 is generally supplied from the PCS
40, which produces the power 440 for end users. The electrical
power 421 and 422, required by the fuel cell control module 34 and
fuel cell balance of plant module 32 respectively, are supplied
from fuel cell electrical module 33. There may be electrical power
supply 423 to the fuel cell module 31. The fuel cell control
module, when stands alone, sends to, and receives from, fuel cell
electrical module 33 the control signals 511 and 514 to control
operations of electrical components there. Similarly, there may
have control signals 512 and 513 between fuel cell electrical
module and fuel cell balance of plant module for control electrical
components operation.
[0039] Similarly, the fuel cell subsystem 30 can be constructed as
other alternatives to one illustrated in FIG. 3a. One of such
alternatives is illustrated in FIG. 3b, in which the output of the
fluid streams from fuel cell subsystem can be from the fuel cell
module 31.
[0040] FIG. 4 illustrates a modular power conditioning subsystem
40. On PCS 40, it first has a control module 46 which controls the
PCS operation. The control module 46 may be communicating with a
centralized control system of fuel cell system 10 by receiving a
control signal 520 and sending a control signal 535. The control
module 46 also sends to, and receives from the electrical module 45
the control signals 521 and 522. There is also an electrical module
45 which collectively installs all electronic devices such as I/O
boards, power sources and switches. Interacting with the PCS
control module 46 and electrical module 45, there generally have
three modular components, namely: [0041] a DC/AC converter module,
which converts the fuel cell produced DC power into AC power for
end use. The DC/AC converter module may have an electrical input
441 and an electrical output 446, and it may receive a control
signal 523 and send a feedback control signal 524. [0042] a DC/DC
converter module, which converts the fuel cell produced unregulated
DC power to regulated DC power, which is then possibly used for
fuel cell system auxiliaries. The DC/DC converter module may have
an electrical input 442 and an electrical output 443, and it may
receive a control signal 525 and send a feedback control signal
526. [0043] an AC/DC converter module, which will convert the AC
power from commercial grid to regulated DC power for use of fuel
cell system auxiliaries. The AC/DC conversion is often necessary
during fuel cell system start up when there is no electrical power
production from fuel cell system. On the AC/DC converter module,
there may have an electrical input 447 and an electrical output
445, and it may receive a control signal 527 and send a feedback
control signal 528.
[0044] On PCS electrical module 45, there is generally a DC
electrical power input port to receive the fuel cell produced DC
power 440, and another input port to receive the AC power 450 from
commercial grid. There is also an output port to deliver the
converted AC power 400 for end use, and another output port for the
regulated DC power 410, either converted from fuel cell produced DC
power or from commercial grid AC power.
[0045] FIG. 5 shows a modular design of heat recovery subsystem 50
according to one of the preferred embodiments of the present
invention. The HRS 50 can generally be constructed by assembling
several independently manufactured sub-modules, namely: [0046] a
heat recovery control module 55, which controls the HRS operation
by collectively installed devices for data acquisition and display.
The control module 55 may receive a control signal 540 from, and
send a control signal 550 to, a centralized control subsystem of
fuel cell system 10. The control system 55 is powered by preferably
a DC power 411 supplied from an electrical module 54, and it may
send a control signal 541 to, and receive a control signal 542 from
the electrical module 54. [0047] an electrical module 54, which
collectively houses all electronic devices for operating the HRS
50. The electrical module 54 is powered by preferably a DC power
410, and outputs a portion of the power 411 to the control module
55 and another portion 412 to a heat recovery balance of plant
module 53. On the module 54, there may be input ports and output
ports for sending and receiving control signals 541 to 544. [0048]
a heat recovery balance of plant module 53, which is a platform to
house, install all necessary auxiliaries such as valves, pumps and
regulators in order to make the HRS 50 functionally operational.
The hot water stream 380 from the fuel cell system 10 returns to
the heat recovery balance of plant module 53, from where it further
flows to a heat storage module (generally a thermal storage tank)
52 by collecting the stream 381. [0049] The circulation
cogeneration water 382 from the storage module 52 is send back to
the fuel cell system via the heat recovery balance of plant module
53 as water stream 360. Between the heat recovery balance of plant
module 53 and the heat storage module 52 there may have control
signals 545 and 546 for operation control; [0050] a heat storage
module 52, which generally is a water storage tank in which the
heat recovered by the HRS is temporally stored. Whenever there is a
thermal demand from the end use, the heat stored will be withdrawn
by supplying a hot water stream 350. A city water stream 390 may be
supplied to the storage module to make up the water withdraw in any
preferred method; [0051] a supplementary heat production module 51,
which, in most cases, includes a supplementary gas burner, and may
preferably be integrated with the heat storage module 52. The
supplementary heat production module 51 is generally provided to
supply the heat demands that are beyond the thermal production
capacity of fuel cell system 10, or that are not available during
the moments of fuel cell operations. A city water stream 390, a
fuel stream 102, and an air stream 202 can be supplied to the
supplementary heat production module 51 for heat production.
[0052] Now referring further to FIGS. 6 and 7 for the concepts of
modular design at subsystem levels. In FIG. 6, the fuel processor
subsystem FPS 20 is made of four modules, i.e. fuel processor
module 21, a balance of plant panel module 22 and a fuel processor
related electrical module and a control module (not shown). All
these modules can be manufactured separately, and once finished
they can be simply integrated by quick connections. The fuel
processor module 21 is preferably a mechanically integrated,
compact fuel processor with only input (QC-109 to QC-114) and
output ports (QC-115 to QC-117) for fluids. As will be described
later, the fuel processor 21 generally consists of multiple devices
such as reformer, burner, steam generator, water-gas shift reactor,
preferential oxidizer and heat exchangers, which are all connected
and integrated inside the fuel processor module 21. One will only
view the input ports and output ports for streams of hydrogen rich
gas 180, combustion flue gas exhaust 240 and warmed cogeneration
water 370. On the fuel processor balance of plant panel module 22,
all fuel processor accessories such as valves, flow meters,
filters, check valves, pressure regulators, compressors are
preferably arranged in a two-dimensional fashion. The components on
the panel 22 can be connected preferably by flexible tubing. The
panel 22 holds all components of the balance of plant and the
collecting ports for accepting input streams of fuel 100, anode off
gas recycling 190, cogeneration water 360 and water to boiler 300.
It also has the connectors for connection of gas streams to the
fuel processor module 21 through preferably flexible tubing 101 for
fuel, 191 for anode off gas recycling, 201 for burner air, 210 for
PROX air, 361 for cogeneration water and 301 for water to boiler.
All the ports are preferably of the quick-connection type, which
allow quick and easy installation. The modules 23 and 24 contain
all power electronics and controls, connecting to the panel 22 by
preferably a cable and interface connectors.
[0053] Similar to fuel processor subsystem module shown in FIG. 2,
fuel cell subsystem module 30, as shown in FIG. 7, is further
divided into three modules: fuel cell module 31, the module of
balance of plant 32 and fuel cell electronics and controls modules
33 and 34. Again, all these modules can be manufactured separately,
and once finished they can be simply integrated by quick
connections. The fuel cell module 31 is preferably a mechanically
integrated, compact subsystem with only input and output ports for
fluids, and inside there are sub-modules of fuel cell stack,
humidifier, heat exchangers, coolant tank and coolant circulation
pump. However, only the input connection ports and output ports can
be seen. On the balance of plant panel module 32, all fuel cell
accessories such as valves, pressure regulators, air blowers
(compressors) are preferably arranged and installed in a
two-dimensional fashion. The hydrogen or hydrogen rich reformate
180, nitrogen (used for stack purging generally) 310, and the
cogeneration water 370 are connected to the panel 32, and after
proper flow arrangement they, together with the cathode air 251 and
cooling air 260, are sent to the fuel cell module 31 through the
connection ports 32a on the panel 32. All the ports are preferably
of the quick-connection type, which allow quick and easy
installation. The modules 33 and 34 contain all power electronics
and controls, connecting to the panel 32 by preferably a cable and
interface connectors.
[0054] The modular design concept at subsystem level described
above can be further illustrated in FIGS. 6 and 7, which
demonstrate the modular design concept at component level. It
should be understood that they are provided here only for
illustration purpose and in practice, the flow arrangement and the
involved components can be determined by the actual process and
application characteristics, which are beyond the scope of this
invention.
[0055] FIG. 6 shows one example of the embodiments according to the
present invention with regard to the fuel processor module 21 and
its balance of plant module 22. As already mentioned earlier, there
are for input ports on the module 22 to be connected to the
external streams: QC-100 for fuel 100, QC-101 for anode off gas
recycling 190, QC-102 for water to boiler 300 and QC-103 for
cogeneration water 360. A hand valve HV-100 is positioned right
after the fuel is entered through QC-100, which will be manually
opened or shutdown for security needs of system operations. Fuel is
passed through a dust filter FL-100 before flowing through two
successively installed solenoid valves SOV-100 and SOV-101, which
in this case are installed based on safety regulations, and will be
actually controlled by a regulatory recognized reliable electronic
controller (not shown). The fuel is then split into two streams;
one is to be sent to the reformer as feed, and the other to be
supplied as supplementary fuel to anode off gas as burner fuel. On
the feed line, there may be installed a solenoid valve SOV-102, a
compressor CPM-100 to lift the feed supply pressure high enough to
overcome the downstream flow resistance (pressure drop), a flow
meter FM-100 to measure and monitor the feed flow rate, and a check
valve CV-100 to prevent any possible backflow, before the feed
stream reaching to the outlet connector QC-104. The supplementary
fuel line will likely see a compressor CMP-101, a solenoid valve
SOV-103, and a pressure regulator PR-100, before it is connected to
the output connector QC-105. The supplementary fuel flow rate is
adjusted by a control mechanism likely based on burner temperature
and on the anode off gas flow rate that is supplied from the
connector QC-101 and mixed with the fuel prior to the QC-105. On
the panel module 24, there may also be installed one water pump
P-100 to deliver the water to the boiler, and two air blowers
BL-100 and BL-101 to supply the air separately to burner, and
preferential oxidizer (PROX) reactor, all inside the fuel processor
module 21.
[0056] It should be understood that all the components within the
module 24 can be mounted on a two-dimensional panel or plate;
therefore it can also be referred to as plate of balance of plant.
This module can be manufactured separately, and the components can
be installed and connected independently. The module will be
eventually installed on a system frame structure, which will
integrate all the system modules into the desired product. The
module will be easily removable from such a frame structure, and be
repaired or replaced.
[0057] Now referring to the fuel processor module 21 in FIG. 6,
there are six input connectors QC-109 to QC-114 to be connected
with the panel module 22 for various streams input, and three
output connectors QC-115 to QC-117 for exiting the streams. The
fuel processor shown schematically herein is a stream reforming
based process developed by the author of the present invention. The
fuel processor consists of several key components, including a
hydrodesulfurizer (HDS), an integrated steam reformer and burner
(SMR+Burner), three heat exchangers (HX-1, HX-2, and HX-3), a
desulfurized feed a superheated steam mixer, a steam boiler, a
medium temperature water gas shift reactor (MTS), a low temperature
water gas shift reactor (LTS), and a preferential oxidizer (PROX).
All the components herein are preferably designed and constructed
separately, and once manufactured they are linked or somehow
stacked together according to the flow scheme to form an integrated
compact device. This feature will allow ease of manufacturing, leak
testing, and assembling. It also allows repairing or replacing
individual components without destroying the entire fuel processor,
once a failure has been detected in a component.
[0058] Now referring to FIG. 7 for fuel cell module 31 and its
balance of plant module 32. Three connectors QC-200, QC-201 and
QC-202 are placed on the panel module 32 to receive fuel stream
180, nitrogen stream 310 and cogeneration water 370. On each of the
fuel and nitrogen line, there may be installed a solenoid valve
(SOV-200 and SOV-201) and pressure regulator (PR-200 and PR-201).
Before either fuel or nitrogen (only used when purging) is
connected to the output connector QC-203, there is a hand valve
HV-200 for manual control. Two air blowers or compressors BL-200
and BL-201 are installed on the panel to supply air to the cathode
of the fuel cell stack and a backup air cooling heat exchanger
HX-2, respectively. The cogeneration water from the connector
QC-202 flows to the connector QC-206, while it might be partially
or completely bypassed through a solenoid valve SOV-202 to the
output connector QC-207, which eventually is connected to the
stream after the output connector QC-213 on the fuel cell module
31.
[0059] The fuel cell module shown schematically in FIG. 7 is
typical of the PEMFC system, which consists of several key
components, including fuel cell stack having an anode, a cathode
and a cooling side. There is an air humidifier, which humidifies
the incoming cool and unsaturated air by exchanging humid and heat
with the cathode exhausting air that is generally saturated at or
near the stack temperature. There may also have another humidifier,
in which the incoming dry hydrogen or semi-hydrated reformate can
be humidified by exchanging humid and heat with the exhausting wet
anode off gas. A heat exchanger HX-1 is placed to remove the heat
that the stack produced to the cogeneration water. A second heat
exchanger HX-2, which differs from the HX-1, is also designed to
serve as a backup heat exchanger, i.e. to remove the extra heat not
sufficiently removed by the HX-1, to ensure an appropriate
temperature of coolant before it flows into the coolant tank. A
coolant circulation pump circulates the coolant back to the stack.
All these components are preferably designed and constructed
separately, and once manufactured they are linked or somehow
stacked together according to the flow scheme to form an integrated
compact device.
[0060] One may remove the PROX reactor, and probably LTS, from the
fuel processor module shown in FIG. 6, when the produced reformate
is supplied to a high temperature membrane fuel cell, in which the
fuel cell stack can safely be operated with reformate containing up
to a few percentage CO (e.g. 5%), therefore only a high and/or
medium temperature water gas shift reactor can satisfy this CO
level requirement. For high temperature fuel cells, it is also
possible to remove one or two humidifiers shown in FIG. 7 because
humidification for high temperature membrane such as
polybenzimidazoles (PBI) based is unnecessary. Instead, there may
be an additional heat exchanger, arranged in a preferred way, to
pre-heat the incoming cold air to close to the stack temperature,
which is generally between 120 and 200.degree. C.
[0061] Furthermore, there may be other variations to the fuel cell
power system 10 of FIG. 1, by separating, combining or rearranging
the basic subsystems, modules and components based on the present
invention. One such example is schematically shown in FIG. 8, which
is one of the preferred embodiments in accordance with the present
invention for a combined heat and power plant based on a steam
reforming based fuel processor and a high temperature membrane
based fuel cell stack. In FIG. 8, the fuel processor module 21 can
be similar to what is shown in FIG. 6 but without LTS and PROX, and
the fuel cell module 31 can be similar to what is shown in FIG. 7
but without two humidifiers, and they can be manufactured
separately as they are for low temperature fuel cell systems. Given
the fact that the MTS temperature is in the same range as the high
temperature fuel cell stack (i.e. 160-200.degree. C.), the fuel
processor module 21 and fuel cell module 31 can even be designed
and manufactured as an integral assembly 60 as shown in FIG. 8, in
which the MTS is expected to be placed in the neighborhood of the
fuel cell stack. Accordingly, the balance of plant modules 22 and
32 for fuel processor subsystem 20 and for fuel cell subsystem 30
can be integrated to form an integrated balance of plant module 25
in FIG. 8, and all the electrical and control modules shown in
FIGS. 2, 3, 4 and 5 can be designed and manufactured as an
integrated assembly 45. In such an arrangement, a steam reforming
and high temperature fuel cell based CHP system 10a will include
five major modules, namely, [0062] an electrical and control
module, in which all electrical and control devices are
collectively installed, to control and operate the CHP system by
interacting with other system modules; [0063] a balance of plant
module, in which all system balance of plant components such as
valves, blowers, compressors, regulators, filters and pumps are
collectively installed. It receives a fuel stream 100 and a water
stream 300 from external supplying sources, and sends a feed stream
101, a fuel stream 191, an air stream 201 and a water stream 301 to
the combined fuel processor and fuel cell module 60. It may also
receive electrical power and control signals from the electrical
and control module 45 by preferably connecting with a cable 560;
[0064] a combined fuel processor and fuel cell module 60, in which
hydrocarbon feed is first converted to a hydrogen rich reformate in
fuel processor part 21, which is subsequently supplied to fuel cell
31 to react with air to generate electricity 400 and usable thermal
energy, with the latter to be recovered by flowing a cogeneration
stream 360 from, and 380 to, a heat recovery module 50. The
combined fuel processor and fuel cell module 60 may receive an
electrical power and a control signal from, and send a control
signal to, the aforementioned electrical and control module 45
through a connecting cable 561; [0065] a power conditioning module
40, which converts and conditions the fuel cell produced power 400
to generate an AC power 440 for end use. This module is essentially
the same as one shown already in FIG. 4. The PCS module 50 is
controlled by interacting with the electrical and control module 45
by connecting a cable 562; and [0066] a heat recovery module 50,
which is essentially the same as one shown in FIG. 5.
[0067] The embodiments of the invention described above are
intended to be exemplary only. The scope of the invention is
therefore intended to be limited solely by the scope of the
appended claims.
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