U.S. patent application number 12/874534 was filed with the patent office on 2011-07-28 for burner for the combustion of hydrogen on a catalyst and boiler for said burners.
This patent application is currently assigned to GIACOMINI S.P.A.. Invention is credited to Corrado GIACOMINI.
Application Number | 20110180023 12/874534 |
Document ID | / |
Family ID | 42651138 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110180023 |
Kind Code |
A1 |
GIACOMINI; Corrado |
July 28, 2011 |
Burner for the Combustion of Hydrogen on a Catalyst and Boiler for
said Burners
Abstract
A burner (20) for the combustion of hydrogen on a catalyst, has
a body (21), a first self-ignition catalyst (23) and a subsequent
group of oxidation catalysts (26), as well as a heat exchanger (35)
heated by the burnt gases, wherein in the burner (20) the heat
exchanger (35) is obtained as a common heat exchanger and it is
arranged outside the body (21) of the burner (20) accommodating the
catalysts (23, 26). A head (22) accommodating the self-ignition
catalyst (23) may be separated by a body (40) accommodating the
oxidation catalysts (26). A second heat exchanger (45), passed
through by cold water, allows production of high purity distilled
water. In the proposed boiler (41) a first part (42) accommodates
the burner modules (20) and another part (43) accommodates the
common heat exchanger (35) and the possible additional heat
exchanger (45) for producing distilled water.
Inventors: |
GIACOMINI; Corrado; (Orta S.
Giulio, IT) |
Assignee: |
GIACOMINI S.P.A.
San Maurizio d'Opaglio (NO)
IT
|
Family ID: |
42651138 |
Appl. No.: |
12/874534 |
Filed: |
September 2, 2010 |
Current U.S.
Class: |
122/4D ;
422/202 |
Current CPC
Class: |
Y02B 30/00 20130101;
F23C 5/08 20130101; F24D 2200/18 20130101; F23C 13/04 20130101;
Y02B 30/14 20130101; F24H 1/0045 20130101; F24D 12/02 20130101 |
Class at
Publication: |
122/4.D ;
422/202 |
International
Class: |
F23C 10/01 20060101
F23C010/01; F28D 21/00 20060101 F28D021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 27, 2010 |
IT |
CO2010A 000005 |
Claims
1. Burner for the combustion of hydrogen on a catalyst,
comprising--in a body for housing the burner--a first self-ignition
catalyst and a subsequent group of oxidation catalysts, as well as
a heat exchanger heated by the burnt gases, characterised in that
the heat exchanger (35) is arranged outside the body (21) of the
burner (20) containing the catalysts (23, 26).
2. Burner according to claim 1, characterised in that the body (21)
of the burner (20) accommodating the catalysts (23, 26) forms a
module for the burner (20).
3. Burner according to claim 2, characterised in that the body (21)
of the burner (20) is formed by a head (22) for accommodating the
self-ignition catalyst (23) and a body (40) accommodating the
oxidation catalyst (26), wherein the head (22) and the body (40)
are separable.
4. Burner according to claim 3, characterised in that the oxidation
catalysts (26) are accommodated in a tubular accommodation (24)
forming the inner wall of a cooling chamber (30) delimited by an
outer jacket (29) having an inlet connection (31) and an outlet
connection (32) for the cooling liquid coming from the separate
heat exchanger (35).
5. Burner according to claim 3, characterised in that provided for
in the head (22) upstream of the self-ignition catalyst (23) is a
chamber (41) for mixing the supplied air and hydrogen.
6. Burner according to claim 4, characterised in that located in
the accommodation (24) holding the oxidation catalyst (26)
downstream of the latter (26) is a reaction chamber (25) receiving
the moist burnt gases.
7. Burner according to claim 1, characterised in that associated
thereto--for supplying the combustion air--is a compressor or a fan
having the pumping head required to overcome loss of head of the
catalysts (20) and of the heat exchanger (35).
8. Arrangement of burners (20) with separate heat exchanger (35)
according to claim 1, characterised in that it comprises an
additional heat exchanger (45), which: a) is associated fluidically
to the common heat exchanger (35) to exploit the heat produced by
the burners (20) better, or b) still impacted by the moist burnt
gases, it is passed through by cold water for the production of
high-purity distilled water.
9. Boiler for housing modules for burners (20) according to claim
1, characterised in that it has a part (42) for accommodating the
modules for burners (20) provided for and a part (43) for
accommodating the sole heat exchanger (35), suitably dimensioned,
common for all the accommodated modular burners (20), regardless of
the number thereof.
10. Boiler according to claim 9, characterised in that it
comprises, between the modular burners (20) and the separate heat
exchanger (35), a conveyor for the moist burnt gases.
11. Boiler according to claim 10, characterised in that it
accommodates an arrangement of modules for burners (20) and heat
exchangers (35, 45).
12. Boiler according to claim 9, characterised in that it has a
vertical arrangement.
Description
DESCRIPTION OF THE INVENTION
[0001] 1. Field of Application
[0002] The present invention refers to a burner for the combustion,
i.e. by oxidation, of hydrogen on a catalyst according to the
preamble of claim 1 and a heater therefor according to the preamble
of claim 9.
[0003] 2. Technological Background and State of the Art
[0004] Burners for the combustion of hydrogen mixed with air are
known in various embodiments. They use, for such purpose, composite
catalysts made up of two types of catalysts i.e. a first
self-ignition catalyst, used for triggering the oxidation of
hydrogen mixed with air, and a subsequent operating catalyst,
usually in several parts, on which the main part of hydrogen
combustion/oxidation is performed.
[0005] Document EP 1.179.709 A2 discloses a burner of this type
used in which--during the triggering step--is a air/hydrogen mixing
ratio which abundantly exceeds the flammability limit (about 4% in
volume of the air/hydrogen mixture ratio) and even nears extremely
hazardous conditions of detonability (air/hydrogen mixing ratio up
to 12.5% in volume). Alongside requiring a regulation system with
two states of the hydrogen flow to the mixing chamber, i.e. a first
flow rate for said primary phase or pre-combustion and a second
rate for the operating combustion, the use of this primary step
with respective catalyst, evidently gives rise to safety problems
both for the people and for the surrounding environment and the
burner itself, thus firstly entailing damage to the catalyst.
Furthermore, an external supply of energy is required in this
burner for triggering the oxidation of hydrogen. It should also be
observed that the mixing air is supplied by means of a tangential
fan, which must also provide for pushing the hot oxidation gases
through the heat exchanger for heating the thermal carrier
fluid.
[0006] Document PCT/EP2006/005686 of the applicant discloses a
zero-emissions hydrogen catalytic burner for heating, wherein the
oxidation of hydrogen occurs without a flame as well as by means of
a composite catalyst having a first catalyst suitable to trigger
the reaction at ambient temperature and a second operating catalyst
which continues and completes the reaction. The air/hydrogen
mixture is controlled mechanically and kept at a value below 4%.
The reaction temperature is about 300.degree. C., hence this allows
preventing the formation of nitrogen oxides harmful for health.
Such burner may be advantageously used for residential building a
heating systems, wherein the outlet water temperature is comprised
between about 40-45.degree. C. For such purpose, the burner
incorporates a heat exchanger for heating water. Therefore, such
burner is made up of a so-called reaction channel and by an
incorporated heat exchanger with igniter plug and therefore the
burner itself forms a complete and functional machine, having power
in the order of magnitude of 6.38 kW. In order to provide greater
power, as usually required for residential building boilers,
several catalytic burners used to be accommodated as a "burners
module" in a casing serving as a heater. Provided for are different
configurations and sizes of casings depending on the number of
burner modules to be accommodated. The latter have an extended
cylindrical shape of about 800 mm and a diameter of about 120 mm,
hence developing in only one direction and this may lead to, for
example in the case of few modular burners, a heater with overall
dimensions extended length-wise and difficult to manage.
[0007] It should also be observed that in the composite catalysts
the self-ignition catalyst is a fragile body and, thus, requires
handling with care to avoid breaking thereof.
SUMMARY OF THE INVENTION
[0008] The task of the present invention is that of simplifying the
burners and indicating boilers for accommodating the same.
[0009] The abovementioned task is attained, according to the
invention, by means of a hydrogen combustion burner on a catalyst
having the characteristics outlined in claim 1 and having a boiler
having the characteristics outlined in claim 9.
[0010] Several and important advantages both for the burners and
for the boilers or heaters accommodated therein are attained
according to the invention by separating the reaction channel from
the heat exchanger.
[0011] According to the invention, the modules to be accommodated
in the heater are no longer formed, as in the previous case, by a
burner incorporating the heat exchanger, but by the burner alone,
while the heat exchanger is provided separated therefrom, wherein
only one heat exchanger shall be provided for in each boiler
regardless of the number of modules, i.e. burners, accommodated in
the heater.
[0012] Several and important advantages are attained with burners
according to the invention.
Regarding the Burners:
[0013] simplified manufacturing and assembly, [0014] the
self-ignition catalyst is easier to handle and positioning thereof
is easy, hence reducing hazards related to breakdowns, and thus the
waste, of these catalysts, which are also quite expensive, [0015]
reduction of the overall dimensions is attained, [0016] the overall
exploitation of the produced heat is efficiently integrated with a
simple cooling chamber of the burner without inserts, [0017] by
providing for separated heat exchangers, the latter may be easily
manufactured by means of any technology, for example as tube heat
exchangers or as radiator heat exchangers.
Regarding the Boiler:
[0017] [0018] due to the fact of accommodating smaller modules, the
casing itself may be smaller and easier to define configuration
thereof, wherein development in vertical direction is equally
allowed, [0019] an easy accommodation of the heat exchanger and
simple access to the heat exchanger are attained, hence for example
facilitating assembly and maintenance operations, [0020] an easy
possibility of accommodating--between the burner modules and the
heat exchanger--a conveyor for the burnt gases towards the heat
exchanger is attained, [0021] easier execution of hydraulic
connections between the modules, in series or parallel, and the
heat exchanger is obtained in a much easier manner, [0022] the use
of a safety circuit excluding damage in case of possible hydraulic
connection between the modules may be provided for, [0023]
according to the invention, further provided for is the use of a
second heat exchanger or auxiliary exchanger, which is
advantageously accommodated in the heater and which, alongside
improving the heat performance, allows producing high purity
distilled water. Such high purity distilled water represents a high
quality product and it is used, for example, in laboratories,
hospitals and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Further characteristics, advantages and details of burners
and boilers according to the invention shall be clearer from the
following description of some embodiments and connection of burners
and boilers according to the invention, illustrated for
exemplifying purposes in the attached drawings, schematically
illustrating, and as representations of the principle, wherein:
[0025] FIG. 1 is a vertical median section through a burner of the
prior art,
[0026] FIG. 2 is a vertical median section through a burner
according to the invention with the separate heat exchanger
associated,
[0027] FIGS. 3A, 3B, 3C and 3D are three different arrangements of
burner modules in a boiler,
[0028] FIG. 4 is a schematic perspective view illustrating a boiler
according to the invention,
[0029] FIG. 5 shows an arrangement of three burner modules
connected in series and to the external heat exchanger;
[0030] FIG. 6 shows the diagram of the three burners connected
parallel and having the external heat exchanger,
[0031] FIG. 7 shows an arrangement of a burner module with the
external exchanger and with the auxiliary heat exchanger for
producing high purity distilled water associated.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0032] First, reference shall be made to FIG. 1, which corresponds
to FIG. 2 of the modular burner illustrated in PCT/EP2006/005686
and shows a median longitudinal section through the same.
[0033] Indicated with 4 in the modular burner 1 is the composite
burner made up of the first self-ignition catalyst 3 and a group 2
of single catalysts which form the group of operating catalysts on
which the hydrogen oxidation reaction is performed. The air and
hydrogen are introduced into the mixing chamber 7 respectively
according to arrows 8 and 100 and the air/hydrogen mixture then
first impacts the self-ignition catalyst 3 and subsequently the
operating catalyst 4 for performing the oxidation of hydrogen with
the ensuing formation of burnt gases and water vapour.
[0034] Indicated with 11 is a toroidal jacket enclosing an
exchanger 5 of the igniter plug type, i.e. extended longitudinally,
and which is impacted by the burnt gases formed thereof. The water
to be heated flows in from the inlet 12A of the exchanger 5 and,
after heating, it is introduced into the toroidal jacket 11 for
further drawing of heat before leaving the burner, arrow 13.
Indicated in 18 and 19 are two turbulators for improving heat
exchange. The burnt gases and the water vapour collected in the
conduction and collection chamber 15 flow out from the burner from
the opening 14.
[0035] As illustrated in the introduction, these burners 1, to be
inserted as modules in the casing of a boiler, are thus modular
burners with incorporated heat exchanger.
[0036] This construction method is entirely abandoned by the
invention, according to which the heat production part, i.e. the
actual burner channel, is separated from the part forming the heat
exchanger, also simultaneously proposed in which is a new
construction for said burner, as initially illustrated in FIG.
2.
[0037] In FIG. 2 the burner 20 has a body 21 which is formed by a
head 22, which contains the ignition catalyst 23, and a body 40
with an accommodation 24 defining a reaction chamber 25, contained
in which is the operating catalyst 26 on which hydrogen oxidation
is performed. The accommodation 24 in turn defines, with the front
sides 27, 28 and an outer jacket 29 a cooling chamber 30 with an
inlet 31 and an outlet 32.
[0038] The composite catalyst 33 is even in this case made up, in a
manner similar to that of the prior art, of the ignition catalyst
23 and the oxidation catalyst 26, wherein both may be provided for
by a plurality adjacent discs. Regarding the composition of
catalysts 23 and 26 reference shall be made to the respective
descriptions of document PCT/EP2006/005686.
[0039] Illustrated as a heat exchanger in FIG. 2 is a plate
exchanger 35 with an inlet 36 and an outlet 37, wherein a pipe 38
connects the inlet 31 of the burner 20 with the outlet 37 of the
exchanger 35.
[0040] Therefore, in the new proposed method of construction, the
head 22 represents an independent element fixable, for example by
means of screws, to the body 40 of the burner 20 containing the
accommodation 24. This solution allows a direct and simple
insertion of the self-ignition catalyst 23 into the head 22 and
practically eliminates inadvertent breaking of the same during
handling thereof. Furthermore, FIG. 2 shows that provided in the
head 22 upstream of the self-ignition catalyst 23 is a chamber 41
for premixing the air and hydrogen supplied in a known manner, such
mixture directly impacting the self-ignition catalyst 23, wherein
also this solution contributes to reduce the overall dimensions of
the burner 20 in its entirety.
[0041] In addition, FIG. 2 shows that in the chamber 30, which does
not have any insertion, the water flowing out from the heat
exchanger 35 is conveyed for cooling the burner, hence allowing, on
one hand, to recover all the heat available on the catalyst 26 and,
on the other hand, it causes the stabilisation of the temperature
of the outer jacket 29.
[0042] Indicated in FIGS. 3A, 3B, 3F and 3C are possible rational
arrangements of the burner modules 20 inside the boiler casing not
illustrated further.
[0043] An exemplifying arrangement of two burner modules 20 in a
boiler is illustrated in FIG. 4, wherein the heater 41 comprises a
first casing 42 accommodating the two modules 20, in a suitably
insulated manner, and a second casing 43 accommodating the heat
exchanger 35. As mentioned above, the heat exchanger 35 according
to the invention is always provided separate from the burner
modules 20 and is always provided for as a single exchanger
regardless of the number of burners 20, wherein the dimensioning
thereof shall be matched from time to time to the provided number
of burners.
[0044] FIGS. 5 and 6 illustrate the connection circuit diagram
between three burner modules 20 and the associated heat exchanger
35, wherein illustrated in FIG. 5 is a series connection and in
FIG. 6 is a parallel connection.
[0045] According to a further disclosure of the invention, and
illustrated in FIG. 7, at a circuit arrangement of the burner 20
and separate heat exchanger 35 analogous to that illustrated in
FIG. 2, additionally provided for with respect to the heat
exchanger 35 is a further heat exchanger 45. This exchanger 45 is
also preferably accommodated in the casing 43 of the boiler 41 and
it has a double function. On one hand, it allows recovering further
heat and further reducing the temperature of the exhaust steam. On
the other hand, this second heat exchanger 45 also allows the
production of high purity distilled water, as mentioned in 46 and
explained hereinafter.
[0046] According to a further aspect of the invention, in order to
perform and optimise the performance and reduce thermal
dispersions, provided for is a conveyor, not illustrated, arranged
in the boiler 41 between the two casings 42 and 43, for directing
the hot air coming from the burner modules 20 towards the mouth 47
of the heat exchanger 35.
[0047] Furthermore, using this conveyor allows using a vertical
geometry for the heat exchanger maintaining the module/s of the
burner 20 horizontal. This solution, not illustrated, allows
further optimising the overall dimensions and improving safety, in
that the hydrogen--being extremely light--it tends to disperse
upwards very fast.
[0048] The separation of the heat exchanger 35 from the burner
module 20 allows the abovementioned reduction of the overall
dimensions of the modules 20 optimizing the spaces to the uttermost
and containing--therein--the same catalysts and at the same amount
and size as provided for the burner disclosed by the document
PCT/EP2006/005686.
[0049] In detail, the channel has a length such to contain the
packet of oxidation or operating catalysts 26, while the
accommodation of the self-ignition catalyst 23 in the head allows
incorporating--inside the latter--the mixing chamber 41 and also
facilitates the assembly and positioning of control probes, not
illustrated.
[0050] According to the invention in order to recover all the
available heat, the accommodation cylinder or jacket 24 is made of
material with good thermal conductivity properties, for example
made of copper and the water circulating in the cooling chamber 30
is the same water flowing out from the heat exchanger 35. The outer
jacket 29 on the contrary shall be made of material with good
thermal insulation properties, so as to prevent excessive heat
dispersion, for example made of stainless steel. The head 22 may be
made of different material, but preferably material having good
insulation properties. The burner modules 20 in the casing 42 shall
be surrounded by a highly insulating material, for example
polyurethane.
[0051] The series or parallel connection illustrated in FIGS. 5 and
6 may be used to integrate the circulation of the water of the heat
exchanger 35 and of the burner modules 20. It should be observed
that the series connection is made in a simple manner but, in case
of inadvertent interruption of the flow of water inside a module
the circulation of water inside the heater is stopped with the
consequent malfunctioning of the same. Though parallel connection
allows overcoming this criticality, manufacturing thereof is more
complex to obtain, but in case of interruption of circulation by a
burner module 20 the heater operates correctly. According to the
invention, provided for higher inherent safety is the integration
of two circuits in series and parallel with a bypass circuit, not
illustrated, actuatable in case of failure of one or more burner
modules or, alternatively, each module may be provided with an
automatic valve, not illustrated, for actuating the circulation of
the water when the reaction begins, wherein this solution is
actuatable solely through the parallel connection.
[0052] Regarding the production of high purity distilled water
according to the invention by means of the additional heat
exchanger 45 all that shall be required is to pass cold water in
the same for total condensation of the burnt gases using water
vapour coming out from the heat exchanger 35, wherein the water
vapour is formed by the catalytic reaction and hence obtaining high
quality water in terms of purity. This heat exchanger 45, operating
as a condensation step, shall be dimensioned taking into account
the temperature coming out from the heat exchanger 35 and the
temperature of the water that is supplied to said heat exchanger
45. It should be observed that the vertical configuration of the
heater allows easily recovering the condensate that is formed in
the heat exchanger 35 or in the exchanger 45 as the condensation
step, wherein--in this manner--the condensate never comes into
contact with the catalysts of the burner modules 20.
[0053] From the structural and functional description illustrated
further above it is observable that the disclosures of the present
invention efficiently execute the indicated task and the
abovementioned advantages are attained.
[0054] Those skilled in the art may introduce modifications and
variants regarding, for example, dividing the separated exchanger
35 into a battery of exchangers, the execution of the body of the
heaters into one or more parts and so on and so forth, without
departing from the scope of protection of the present invention as
described in the claims that follow.
* * * * *