U.S. patent application number 12/875160 was filed with the patent office on 2011-07-28 for hydrogen generator system for a catalytic hydrogen burner.
This patent application is currently assigned to GIACOMINI S.P.A.. Invention is credited to Corrado GIACOMINI.
Application Number | 20110180396 12/875160 |
Document ID | / |
Family ID | 42634546 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110180396 |
Kind Code |
A1 |
GIACOMINI; Corrado |
July 28, 2011 |
HYDROGEN GENERATOR SYSTEM FOR A CATALYTIC HYDROGEN BURNER
Abstract
A hydrogen generator system (1) for a hydrogen powered unit or
user (3), such as for example a catalytic hydrogen burner or a fuel
cell, includes an electrolyzer (2) for the electrolysis of
distilled water, producing hydrogen and oxygen, provided with a
demineralizer device (5) and an A/C transformer/converter unit (7)
for supplying electrical power for the electrolysis process and, on
the outlet side, a device for purifying the hydrogen produced, such
system (1) further includes: a device (10) for recovering the heat
generated by the electrolysis process and/or a device (17) for
storing the hydrogen produced, such hydrogen generator system (1)
is accommodated in a casing (20) which has--externally--inlet and
outlet connection fittings.
Inventors: |
GIACOMINI; Corrado; (Orta S.
Giulio, IT) |
Assignee: |
GIACOMINI S.P.A.
San Maurizio d'Opaglio (NO)
IT
|
Family ID: |
42634546 |
Appl. No.: |
12/875160 |
Filed: |
September 3, 2010 |
Current U.S.
Class: |
204/229.4 ;
204/232 |
Current CPC
Class: |
H01M 8/0656 20130101;
H01M 16/003 20130101; Y02E 60/50 20130101; Y02P 90/40 20151101;
H01M 8/0643 20130101; H01M 8/186 20130101; Y02E 60/36 20130101;
Y02E 60/528 20130101; Y02P 20/133 20151101; Y02E 60/366 20130101;
H01M 8/0687 20130101 |
Class at
Publication: |
204/229.4 ;
204/232 |
International
Class: |
C25B 1/04 20060101
C25B001/04; C25B 9/00 20060101 C25B009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2010 |
IT |
CO2010A 000003 |
Claims
1. Hydrogen generator system for a hydrogen powered unit, such as
for example a hydrogen catalytic burner or a fuel cell, comprising
an electrolyser for the electrolysis of distilled water, producing
hydrogen and oxygen, containing, on the inlet side, an associated
demineralizer device and an associated A/C transformer/converter
unit for supplying electrical power for the electrolysis process
and, on the outlet side, a device for purifying the hydrogen
produced with the subsequent exit of the hydrogen to be supplied to
the hydrogen powered unit, as well as production of oxygen,
characterised in that it also comprises: a device (10) for
recovering the heat generated by the electrolysis process
associated to the electrolyser (2), and/or a device (17) for
storing the hydrogen produced, and in that the entire system (1)
for generating hydrogen is accommodated in a casing (20), which
has--externally--inlet connection fittings, for the water and
electrical power supply systems for feeding the electrolyser (2),
and outlet fittings for the generated hydrogen and for delivery and
return pipes of a heating system, for example that of a house, to
be connected to said heat recovery device (10).
2. Hydrogen generator system (1), according to claim 1,
characterised in that the device (10) for recovering the
electrolysis heat is formed by a heat exchanger (10), whose primary
circuit (11) is arranged in the electrolyser (2) and whose
secondary circuit (13) is connected to a heat user (16), for
example to a household or industrial heating system.
3. Hydrogen generator system (1) according to claim 1,
characterised in that the device (17) for storing hydrogen is a
tank under pressure or contains metal hydrides and forms or
comprises a hydrogen storage tank, wherein said storage of hydrogen
occurs at low pressure, for example at 6 bars maximum.
4. Hydrogen generator system (1), according to claim 1,
characterised in that the hydrogen storage device (17) is a
pressure storage device with or without compressor.
5. Hydrogen generator system (1), according to claim 1,
characterised in that it provides for a direct outlet of the
hydrogen produced, which is associable to a hydrogen inlet/outlet
of a hydrogen storage device (17) with metal hydrides, and in that
it provides for--in the secondary circuit (13) of the heat
exchanger (10)--a diversion for supplying heat to the storage
device (17). (FIG. 2)
6. Hydrogen generator system (1) according to claim 1,
characterised in that it provides for a double hydrogen outlet,
i.e. a first outlet derived directly from the electrolyser (2) at
low pressure and purified preliminarily, as well as a second
hydrogen outlet coming from the hydrogen storage device (16) with
metal hydrides and having a higher degree of purification, metals,
and in that it provides for--in the secondary circuit (17) of the
heat exchanger (10)--a diversion for supplying heat to the storage
device (17). (FIG. 3)
7. Hydrogen generator system (1), according to claim 1,
characterised in that it comprises a centralised control device
supported by a programmable software and suitable to manage--in the
most rational manner possible--the control and adjustment of all
controllable circuit devices and components to obtain utmost
efficiency and consumption.
8. Hydrogen generator system (1), according to claim 3,
characterised in that it uses an alloy of metal hydrides which
during the step of releasing hydrogen it requires a heat supply
capable of operating at ambient temperature or slightly higher,
wherein said amount of heat is preferably derived from the recovery
of the electrolysis heat.
9. Hydrogen generator system (1), according to claim 2,
characterised in that the device (10) heat exchanger cools the
electrolyser (2).
10. Hydrogen generator system (1), according to claim 1,
characterised in that it forms--with said casing (20) for
accommodating the system (1)--a preassembled unit (21) ready to be
installed and connected directly with the inlet and outlet lines.
Description
DESCRIPTION OF THE INVENTION
[0001] 1. Field of Application
[0002] The present invention refers to a hydrogen generator system
for a catalytic hydrogen burner according to the preamble of claim
1.
[0003] 2. Technological Background and State of the Art
[0004] Recently developed, as an alternative to the known liquid
fuel or gas heaters for producing heat, respectively for heating
systems, were burners for catalytic hydrogen combustion with the
ignition of the reaction at ambient temperature, without the
formation of a flame, with reaction below the temperature of
formation of NO.sub.x, with exhaust product solely made up of hot
moist air, and with the heat transferred entirely to a heat
exchanger for heating water of a heating system, for example of the
radiant type, in particular for residential buildings, i.e. with
surfaces for example up to about 250-300 m.sup.2. Hydrogen
catalytic burners of the indicated type are disclosed, for example,
by document WO 2005/024301 of the applicant. The supply of hydrogen
therein is provided for at low pressures, for example in the order
of 2-5 bars, where the supply of hydrogen must be ensured in a
reliable, safe and continuous manner.
[0005] Production of hydrogen at industrial level is obtained
through electrolysis of distilled water in alkaline electrolysers,
obtaining oxygen and hydrogen. Suitably demineralised supply system
water is supplied to the electrolysers and the required electrical
energy is supplied from the electrical supplky supply system using
an A/C transformer/converter unit, generally supplied with
three-phase current following the high current values and low
voltage values required, wherein heat is developed during the
electrolysis process. For practical use of the abovementioned
hydrogen catalytic burners it is necessary to provide a suitable
supply of hydrogen, i.e. continuous, at low pressure and with a
suitable degree of purity of hydrogen. One such supply is currently
available with plants or systems solely for generating hydrogen and
oxygen assembled with devices or components available in the
market, generally provided for industrial production of
hydrogen.
[0006] Thus, such systems reveal the following drawbacks: [0007]
they are generally made up of components or devices recovered
occasionally on the market, possibly modified and not designed in
function of the unit in question, [0008] these systems are
generally quite complex for the hydraulic and electric installation
technicians, in that they require quite long assembly and
installation times, errors may occur and they require a lot of
space, [0009] performance thereof is improvable, [0010] often used
are proton exchange membrane (PEM) electrolytic cells, which
actually provide higher purity of hydrogen with respect to the use
of electrolytic cells provided for according to the invention, but
have correspondingly higher costs and a more limited duration,
[0011] heat is developed during electrolysis, hence lowering the
performance of the system, [0012] an interruption of the electrical
energy entails an interruption of the production of hydrogen,
[0013] provided for is the sole production of hydrogen and
oxygen,
SUMMARY OF THE INVENTION
[0014] Thus, the task on which the present invention is based is
that of providing a hydrogen generator system for obtaining
hydrogen catalytic burners of the indicated type capable of
overcoming the drawbacks of the prior art systems and capable of
providing hydrogen produced with sufficient degree of purity in a
reliable and continuous manner as well as obtainable in an
inexpensive manner and with an improved performance.
[0015] A hydrogen generator system simplifying construction and
installation thereof falls within the task of this invention
[0016] The abovementioned task is obtained by means of a hydrogen
generator system for hydrogen catalytic burners having the
characteristics of claim 1. Further advantageous developments and
embodiments are observable from the dependent claims.
[0017] The hydrogen generator system according to the invention
allows attaining various important advantages obtained starting
from the known production of hydrogen through electrolysis of
distilled water and by using more rational formation criteria for
the single blocks into which the proposed hydrogen generator system
may be divided as illustrated more in detail hereinafter.
[0018] Another advantage of the proposed hydrogen generator lies in
the exploitation of the heat that is developed inside the
electrolyser during the electrolysis process, such heat being
advantageously useable as an integration of the pre-existent system
for heating and/or producing domestic hot water.
[0019] Reliable continuous supply of the produced hydrogen, even
during possible interruptions of the electrolysis process, may be
guaranteed in a further development of the base hydrogen
generator.
[0020] Obtained in a further development of the hydrogen generator
according to the invention is a suitable purification of hydrogen
using simple and inexpensive means.
[0021] Furthermore, a common advantage for all embodiments of the
hydrogen generator according to the invention lies in the fact of
providing a choice, targeted design and dimensions of the single
components required for obtaining the proposed hydrogen generator,
hence said circuit may be advantageously assembled in a compact
manner and accommodated in an installable casing inside or outside
the house.
[0022] Such casing shall thus be provided--externally--with inlet
fittings and outlet fittings alone, thus further facilitating the
connection of said casing, i.e. of the hydrogen generator according
to the invention, during the execution of the respective
connections.
[0023] Providing for a supply of electrical energy produced from
renewable sources (solar, wind energy, biogas) alongside the
presence of storage of hydrogen, allows obtaining an independent,
continuous and inexpensive operation, wherein hydrogen may be
produced substantially continuously when the renewable source is
available and stored for use thereof when actually required.
[0024] Furthermore, it is advantageous to provide a plurality of
embodiments of the proposed hydrogen generator, which are capable
of meeting the various characteristics to be taken into account
depending on the function of the unit to be supplied with hydrogen,
for example depending on the degree of purity of hydrogen, which is
fundamental should one decide to supply the catalytic burner or any
other unit, for example a fuel cell, or even the pressure or flow
rate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Further characteristics, advantages and details of the
hydrogen generator system for a hydrogen-powered unit, such as for
example a catalytic hydrogen burner, are observable from the
following description of some preferred embodiments, illustrated
for exemplifying purposes in the attached drawings, to which
reference shall be made even for possible details not outlined in
detail in the description that follows, and wherein:
[0026] FIG. 1 schematically shows an embodiment of a hydrogen
generator system for a hydrogen-powered unit, and
[0027] FIGS. 2 to 5 schematically show further embodiments of the
hydrogen generator system according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] In the various figures identical or functionally equivalent
components of the proposed system have identical reference
numbers.
[0029] First, reference is made to a base embodiment illustrated in
FIG. 1,
[0030] wherein the hydrogen generator system according to the
invention is indicated in its entirety with 1. The proposed system
1 comprises an electrolyser 2, i.e. an electrolytic cell,
containing a base alkaline solution (KOH) for the process of
electrolysis of distilled water for the production of oxygen and
hydrogen. Alkaline electrolysers are convenient in terms of costs.
Also alternatively used may be PEM electrolysers, i.e. having a
proton exchange membrane, such electrolysers being more expensive
but obtaining higher purity of the supplied hydrogen. Hydrogen, in
case of a catalytic burner 3, is supplied for example at the
pressure of 5 bars, where the control of the production occurs
through the value of the pressure.
[0031] The produced oxygen 4 may be released into the
atmosphere.
[0032] The water to be subjected to electrolysis is obtained from
the supply network and demineralised in a demineralizer 5,
advantageously of the reverse osmosis type, which provides high
purity of the distilled water suitable for the water electrolysis
requirements.
[0033] Advantageously, the demineralizer 5 is connected to a tank
6, which automatically requires filling thereof with demineralised
water when the level of the water therein drops beneath an
adjustable minimum threshold level. Even the dimensioning of the
tank 6, provided to have the desired operation autonomy, is
performed to have a smallest overall dimension possible. The tank 6
allows obtaining a constant operating safety even in case of
possible interruption of the water of the supply system.
[0034] The electrical energy required for the electrolysis process
may be drawn from the supply system, for example from a three-phase
power supply system following the high absorptions of the
electrolysis process (about 5 KW per cubic meter of the produced
hydrogen), by means of an A/C transformer/converter intermediate
unit 7 provided with a control system, not illustrated.
[0035] Alternatively provided for may be drawing electrical energy
from a renewable source, such as for example a solar, wind energy
or biogas system, not illustrated.
[0036] As mentioned beforehand, hydrogen is produced at a much
lower pressure, for example 5 bars due to reasons related to the
safety and duration of the system, wherein the hydrogen produced
through alkaline electrolysis may have traces of a base solution,
however having a purity exceeding 99%, and thus sufficient for a
catalytic burner, while the remaining part is formed by water in
vapour state or very slight traces of oxygen. It should be herein
observed that such impurities are uninfluential should one decide
to store hydrogen at low pressures (as illustrated more in detail
hereinafter) or in case of use of hydrogen in combustion processes,
as in the case of catalytic burners, while they are influential in
case of power supplying the fuel cells, which require purities of
higher degree, to avoid occurrence of damage thereon.
[0037] Further purification of the gases may require, as known, a
step 8 for the condensation of hydrogen through a chiller, not
illustrated, which may allow attaining an extremely high degree of
purity of 4.5 (99.995%). These chillers are however extremely
cumbersome and have high electrical energy consumptions to reduce
possible water residues, which are actually uninfluential for the
combustion, which generates water vapour.
[0038] However, as mentioned above in the case of hydrogen
catalytic burners, lower purity is required, for example at least
99.5%, which is doubtlessly obtainable through the mentioned steps
of condensation 8 supplied by a chiller.
[0039] According to the invention one may waiver the use of
chillers and add to the stage of condensation 8--instead--an active
carbon and teflon filter 9 for eliminating possible electrolytic
residues. This allows obtaining a less expensive and more compact
solution. Possible traces of oxygen are actually uninfluential,
given that hydrogen is intended for a combustion process.
[0040] A further teaching of the invention lies in the recovery of
the heat generated in the electrolyser, i.e. in the electrolytic
cell 2 during the electrolysis process, providing for a heat
exchanger device 10 associated to the electrolyser 2. The primary
circuit 11 of the heat exchanger 10 is inserted into the
electrolyser 2 and contains a circulation pump 12. The secondary
circuit 13 has a delivery 14 and a return 15 means associated to a
heating system 16. This heat exchanger device 10 constitutes a
source of heat which allows boosting the performance and energy
balance of the hydrogen generator system 1, wherein the heat
exchanger 10 also serves for cooling the electrolyser 2.
[0041] It should be observed that regarding this, generally, 1
Nm.sup.3 of hydrogen are required for producing about 5.3 KW of
electrical energy, 3.5 KW of which are actually used for
electrolysis, while the rest is substantially dissipated in heat
and by the hydrogen generator system 1 itself, for example through
its electric control panel, sensors, fans and so on and so forth.
The recovery illustrated above allows the performance of the
electrolytic cell 2 to exceed 90%.
[0042] Provided for according to a further important teaching of
the present invention is the storage of the produced hydrogen,
FIGS. 2, 3, 4 and 5. Due to reasons related to the space and
simultaneously to the purification of hydrogen, the storage device
provided for may either be based on a pressure storage, possibly
increased by means of a compressor, or on a storage based on the
absorption of hydrogen through metal hydrides, which have the
capacity to absorb hydrogen thereinto then releasing it, wherein
this solution allows having low-pressure storage devices and having
an optimal capacity with respect to the volume.
[0043] As known, metal hydrides must be cooled when they absorb
hydrogen while they develop heat when they release it. This
development of heat may be more or less relevant depending on the
composition of the alloy of the abovementioned metal hydrides,
wherein the ideal solution would be operating at ambient
temperature, or slightly higher with respect thereto. According to
the invention the required supply of heat may come from the heat
recovery 10 of the electrolysis process, hence--in this sense--the
system 1 may be autonomous, FIGS. 2 and 3. Provided for in this
case are electrically actuated three-way valves 22 and 23, of which
the first (22) serves for by-passing the storage device 17 while
the second (23) regulates the temperature according to the needs
mixing the water. As an alternative to this, heat may be produced
through an external source of heat, for example by means of an
electric resistance, not illustrated.
[0044] Another important advantage attained through the storage of
hydrogen on a solid base, i.e. metal hydrides, lies in the fact
that, alongside storing a good amount of hydrogen therein, the
metal hydrides also allow further purification of hydrogen,
advantageous for combustion thereof, wherein this allows obtaining
a purification unit per se included in the storage device 17.
[0045] Therefore, in cases where the unit or user does not require
particular purity, like in the case of a catalytic burner 3, the
unit may directly draw hydrogen from the electrolyser 2 and/or from
the storage device 17. Therefore, the hydrogen generator system 1
may have two outlets for the gas, FIG. 3, i.e. an outlet 18 for
purified hydrogen solely from the filter 9 and no longer from the
storage device 17 directly provided by the electrolyser 2, and an
outlet 19 for purer hydrogen, i.e. purified both by the filter 9
and by the storage device 16, and coming from the latter. The two
outlets 18 and 19 may supply the same unit or, as illustrated, two
units requiring different degrees of purity of hydrogen.
[0046] Alternatively, the storage of hydrogen may be obtained by
means of a container under pressure, which may be the same one
provided by the electrolyser 2 or it may be increased by a
compressor, not illustrated, FIG. 5. The embodiment of FIG. 4 shows
a hydrogen generator system 1 with separate heat management and
storage system.
[0047] The embodiment of FIG. 5 illustrates a hydrogen generator
system 1 according to the invention with storage of hydrogen under
pressure, without a compressor.
[0048] In all the embodiments illustrated above, improving
performance and consumptions requires a more rational management of
all circuit components and devices of the proposed system 1. Thus,
proposed according to the invention is the use of a logic, assisted
by a software, suitable to run the entire system, wherein for
example the production of hydrogen should function only if the
storage of sterilized water in the tank 6 of the demineralizer 5
and the storage of hydrogen in the storage device 17 drop below the
preset thresholds. Provided for the production of hydrogen and
management of the storage of hydrogen is a pressure control;
wherein--up to a given level or lower threshold--hydrogen is drawn
from the storage device 17, after which rechargeing thereof is
performed and/or the unit 3 is supplied with con hydrogen directly
by the electrolyser 2. Such solutions are provided for exemplifying
purposes and they are made using corresponding circuit arrangements
of the hydrogen generator systems 1 as illustrated in the
drawings.
[0049] A further teaching of the present invention lies in
accommodating--in a casing 20--a preassembled circuit or hydrogen
generation system 1 according to the invention, made in the most
compact manner possible according to the criteria illustrated
further above. In such manner, said casing 20 and the hydrogen
generator system 1 accommodated therein form a unit 21 that is
compact and installable in a simple and quick manner and excluding
possible errors related to the formation of the various circuits
provided for. The unit 21 shall externally be solely provided with
the required inlet and outlet fittings. Thus this shall also allow
quick and safe performance of the various connections, for example
to the water supply system pipe, to the source of electrical power,
as well as to the hydrogen outlet pipe/s 18, 19 for the units in
question, as well as for the delivery 14 and return 15 pipes of the
exchanger 10 to be connected to a heating system 16, for example of
the radiant type for a residential building, completed with a solar
system.
[0050] From the structural and functional description outlined
above it is observable that the hydrogen generator systems for
catalytic burners according to the invention allow an efficient
fulfilment of the indicated task and attaining the aforementioned
advantages.
[0051] What has been described above related to a catalytic burner
is obviously valid even for other hydrogen-powered units, like in
the case of fuel cells, which may be advantageously used for
producing electrical energy as a back-up service, for example in
hospitals to replace the common batteries, wherein also used in
such hospitals may be the produced oxygen and, for heating
purposes, if combined with a catalytic burner likewise supplied
with the produced hydrogen.
[0052] Following are two examples regarding the dimensioning of a
hydrogen generator system 1 according to the criteria and of the
invention illustrated above, respectively for a catalytic burner
and for a fuel cell.
Example 1
Catalytic Burner
[0053] Project Data:
[0054] User: 5.8 kW catalytic burner, 1.67 Nm3/h hydrogen
consumption
[0055] Storage duration: 12 hours
[0056] Duration of recharge cycle: 12 hours
[0057] Hypothesis for drawing solely from the storage and not
directly from the producer.
[0058] Dimensioning:
Minimum dimension of the storage means = 1.67 m 3 h 12 h = 20 m 3 =
20000 l ##EQU00001## Minimum electrolyser flow rate = 2 m 3 h
##EQU00001.2##
[0059] Where the required flow rate was rounded off to the higher
number for a safety factor and to near the flow rates available in
the market.
[0060] Amount of distilled water required to fill the
storage means = 20 m 3 0.87 l m 3 = 17.4 l ##EQU00002##
[0061] Where 0.87 represents the standard consumption of the
electrolyser. A 20 litre storage means is assumed for the sake of
safety.
Minimum water treatment flow rate = 20 l / 12 h = 1.67 l h
##EQU00003##
[0062] N.B. In this calculation example, the m.sup.3 shall be
considered under normal conditions.
[0063] Results:
[0064] Water treatment (minimum flow rate)=1.67 l/h
[0065] Demineralised water storage=20 litres
[0066] Electrolysis (recommended flow rate)=2 Nm3/h
[0067] Hydrogen storage=20000 litres
Example 2
Fuel Cell
[0068] Project Data:
[0069] User: 1 kW fuel cell, 14 litres/minute hydrogen
consumption
[0070] Storage duration: 8 ore
[0071] Duration of recharge cycle: 12 ore
[0072] Hypothesis for drawing solely from the storage and not
directly from the electrolyser.
[0073] Dimensioning:
User = 14 litres min 60 1000 = 0.84 m 3 h 1 m 3 h ##EQU00004##
[0074] In this dimensioning, the maximum consumption of hydrogen
was rounded off to the higher value so as to have a safety
margin.
Minimum dimension of the storage means = 1 m 3 h 8 h = 8 m 3 = 8000
l ##EQU00005## Minimum flow rate of the electrolyser = 8 m 3 / 12 h
= 0.67 m 3 h ##EQU00005.2##
[0075] Amount of distilled water required to fill the
storage means = 8 m 3 0.87 l m 3 = 6.96 l ##EQU00006##
[0076] Where 0.87 is the standard consumption of an electrolyser. A
10 litre storage means is assumed for the sake of safety.
Minimum water treatment flow rate = 10 l / 12 h = 0 , 83 l h
##EQU00007##
[0077] In this calculation example, the m.sup.3 shall be considered
under normal conditions.
Results:
[0078] Water treatment (minimum flow rate)=0.83 l/h
[0079] Demineralised water storage=10 litres
[0080] Electrolysis (minimum flow rate)=0.67 Nm.sup.3/h
[0081] Hydrogen storage=8000 litres
[0082] In this case, considering the substantial storage of
hydrogen, the storage device may be provided for outside the casing
20, i.e. unit 21.
[0083] In practice, those skilled in the art may introduce various
modifications and variants, such as for example providing for some
components outside the described casing 20 of unit 21, replacing
some components with other substantially functionally equivalent
elements, same case applying to providing different fields of
application, such as for example heating systems for industrial
use, such us for example heating greenhouses, or using oxygen for
oxygenating water for fish tanks in fish farming and so on and so
forth, without departing from the scope of protection of the
present invention as described and claimed in the attached
claims.
* * * * *