Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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METHOD AND APPARATUS FOR PRODUCING AND SEPARATING
COMBUSTIBLE GASSES
FIELD OF THE INVENTION
This invention relates to a method and apparatus for producing and
separating combustible gasses. More particularly, this invention relates to an
electrolysis cell and method in which hydrogen gas and oxygen gas
produced through the electrolysis of an aqueous electrolytic solution are
separated upon production.
BACKGROUND TO THE INVENTION
An electrolysis cell uses electricity to convert water to hydrogen and oxygen
in gas phase. A known electrolysis cell includes a proton exchange
membrane in order to separate the hydrogen and oxygen gases produced
through the electrolysis process. The electrolysis cell further includes an
anode positioned along a first face of the proton exchange membrane and a
cathode positioned along a second opposite face of the proton exchange
membrane.
A known proton exchange membrane is a semi-permeable membrane
jenerally made from ionomers and designed to conduct protons while being
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impermeable to gases, such as oxygen and hydrogen. The essential function
of the proton exchange membrane, when incorporated into the electrolysis
cell, is to separate reactants and to transport protons. Proton exchange
membranes can be made from either pure polymer membranes or from
composite membranes where other materials are embedded in a polymer
matrix.
A first disadvantage of the known proton exchange membrane is the high
cost of the membrane, since it requires that a noble-metal catalyst (typically
platinum) be used to separate the hydrogen's electrons and protons. The
platinum catalyst is also extremely sensitive to carbon monoxide poisoning,
making it necessary to employ an additional reactor to reduce carbon
monoxide in the fuel gas if the hydrogen is derived from an alcohol or
hydrocarbon fuel. This again adds to the cost of using the known proton
exchange membrane.
Further disadvantages of the know proton exchange membranes are their
poor conductivity at lower relative humidity and their poor mechanical
properties at temperatures above approximately 100 C. The operating
temperature of these membranes is relatively low and temperatures near 100
C are not high enough to perform useful cogeneration.
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In this specification, the term "combustible fluid" includes within its scope
combustible gas containing predominantly hydrogen and,or oxygen in gas
phase.
OBJECT OF THE INVENTION
It is accordingly an object of the present invention to provide a method and
apparatus for producing and separating combustible gasses, with which the
above disadvantages may be overcome and which are useful alternatives to
known electrolysis cells and methods for separating combustible gasses.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a method for
separating combustible fluid produced from an electrolytic solution during a
process of electrolysis including the steps of:
providing an electrolytic solution;
- providing an electrolysing apparatus having first and second
spaced apart foraminous members, defining a first chamber
between them, having at least one inlet, and both foraminous
members being located between first and second electrodes so
that a first combustible fluid collection chamber, having a first
combustible fluid outlet, is defined hetvveen the first foraminous
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member and the first electrode and a second combustible fluid
collection chamber, having a second combustible fluid outlet is
defined between the second foraminous member and the second
electrode;
- passing the solution into the first chamber via an inlet, so that the
solution passes simultaneously through both foraminous members
into the first and second combustible fluid collection chambers; and
applying a voltage across the electrodes to electrolyse the solution
in the first and second combustible fluid collection chambers, so
that a first combustible fluid forms in the first combustible fluid
collection chamber and a second combustible fluid forms in the
second combustible fluid collection chamber, and the first
combustible fluid passes out of the first combustible fluid collection
chamber via the first combustible fluid outlet and the second
combustible fluid passes out of the second combustible fluid
collection chamber via the second combustible fluid outlet.
The first and second electrodes may be a first outer electrode and a second
outer electrode and the method may include the step of providing a plurality
of intermediate floating electrodes.
The first foraminous member and the second foraminous member defining
the first chamber and having at least one inlet, may together be a set of
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foraminous members. and the method may include the step of providing a
plurality of sets of foraminous members arranged in a back-to-back
configuration with one intermediate floating electrode disposed between
adjacent sets of foraminous members.
5
The electrolysing apparatus may define at least one inlet passage in fluid
flow communication with all of the inlets and the method may include the step
of passing the solution into the first chambers of all of the sets of
foraminous
members via the inlet passage.
The electrolysing apparatus may define at least one first combustible fluid
outlet passage in fluid flow communication with all of the first combustible
fluid outlets and a second combustible fluid outlet passage in fluid flow
communication with all of the second combustible fluid outlets, the
arrangement being such that the first combustible fluid formed in the first
combustible fluid collection chamber passes out of the apparatus via the first
combustible fluid outlet passage and the second combustible fluid formed in
the second combustible fluid collection chamber passes out of the apparatus
via the second combustible fluid outlet passage.
According to a second aspect of the invention there is provided an
electrolysing apparatus in which combustible fluid produced from an
electrolytic solution during a process of electrolysis is separated
comprising:
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- first and second spaced apart electrodes,-
- first and second spaced apart foraminous members located
between the first and second electrodes;
- a first chamber defined between the first and second
foraminous members;
- a first combustible fluid collection chamber defined between the
first foraminous member and the first electrode;
- a second combustible fluid collection chamber defined between
the second foraminous member and the second electrode;
- at least one inlet into the first chamber for the electrolytic
solution;
- a first combustible fluid outlet from the first combustible fluid
collection chamber; and
- a second combustible fluid outlet from the second combustible
fluid collection chamber,
the arrangement being such that the electrolytic solution passes into
the first chamber via the inlet and passes simultaneously through both
foraminous members into the first and second combustible fluid
collection chambers respectively where electrolysis takes place; and
such that a first combustible fluid forms in the first combustible fluid
collection chamber; and such that a second combustible fluid forms in
the second combustible fluid collection chamber; and such that the
first combustible fluid passes out of the first combustible fluid
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collection chamber via the first combustible fluid outlet; and such that
the second combustible fluid passes out of the second combustible
fluid collection chamber via the second combustible fluid outlet.
The first electrode may be a first outer electrode and the second electrode
may be a second outer electrode, and the apparatus may include a plurality
of intermediate floating electrodes.
The first foraminous member and the second foraminous member defining
the first chamber and having the at least one inlet, may be a set of
foraminous members and the apparatus may include a plurality of sets of
foraminous members connected to one another in a back-to-back
configuration with one intermediate floating electrode positioned between
adjacent sets of foraminous members.
The electrolysing apparatus may include a gasket positioned in the peripheral
region between the two foraminous members forming the set of foraminous
members.
The gasket may be a first gasket and the electrolysing apparatus may include
a plurality of second gaskets, each positioned in the peripheral region
between adjacent sets of foraminous members, surrounding the outer
periphery of the intermediate floating electrode.
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Each foraminous member may be provided with spacing means projecting
from both faces thereof to space the foraminous member from the adjacent
foraminous member and electrode.
The first and second outer electrodes may each be provided with a connector
for connecting to a power supply to supply a voltage over the electrolysing
apparatus to electrolyse the electrolytic solution.
The electrodes and foraminous members may all be disc shaped, so that the
apparatus is cylindrical in shape.
The apparatus may include circulating means, such as a pump, to circulate
the solution through the apparatus and to force the solution into the first
chamber.
The inlets of the foraminous members may be aligned to define an inlet
passage, so that electrolytic solution is passed into all of the first
chambers of
the apparatus via the inlet passage.
The first combustible fluid outlets may be aligned to define a first
combustible
fluid outlet passage, so that first combustible fluid produced in all of the
first
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combustible fluid collection chambers passes out of the apparatus via the
first combustible fluid outlet passage.
The second combustible fluid outlets may be aligned to define a second
combustible fluid outlet passage, so that second combustible fluid produced
in all of the second combustible fluid collection chambers passes out of the
apparatus via the second combustible fluid outlet passage.
The apparatus may include a first combustible fluid collection container
connected to the first combustible fluid outlet passage and a second
combustible fluid collection container connected to the second combustible
fluid outlet passage.
The first and second combustible fluid collection containers may each have a
second electrolytic solution outlet located towards the operatively bottom end
of each container and a first combustible gas and second combustible gas
outlet located towards the operatively top end of the first and second
combustible fluid collection containers respectively, the arrangement being
such that electrolytic solution may pass out of the first and second
combustible fluid outlets from the first and second combustible fluid
collection
chambers, together with the respective gases, into the first and second
combustible fluid collection containers respectively, whereafter first and
second combustible gasses are passed out of the containers via the first and
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second combustible gas outlets and the electrolytic solution is passed out of
the containers via the second electrolytic solution outlets and may be
circulated back to the inlets via the circulating means.
5 BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described further by way of a non-limiting example
with reference to the accompanying drawings wherein:
10 figure 1 is an exploded perspective view of part of an electrolysis
apparatus according to a preferred embodiment of the
invention;
figure 2 is a perspective view of the electrolysis apparatus of figure 1;
and
figure 3 is a cross-sectional side view of the apparatus of figure 2 along
line lli-Ill.
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Referring to the drawings, an electrolysing apparatus according to a
preferred embodiment of the invention is generally designated by reference
numeral 10.
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The electrolysing apparatus 10 is adapted to produce and separate
combustible fluid, particularly combustible fluid containing predominately
oxygen and hydrogen, formed during the electrolysis of an electrolytic
solution disposed in the apparatus 10. The apparatus 10 comprises a first
outer electrode 12, being an anode, and a second outer electrode 14, being a
cathode. The first and second outer electrodes 12 and 14 are arranged
generally parallel to one another and are spaced from one another.
The apparatus 10 further includes two spaced apart foraminous members, a
first foraminous member 16 and a second foraminous member 18. The two
foraminous members 16 and 18 are also arranged generally parallel to one
another, are spaced from one another, and are both located between the two
end electrodes 12 and 14. A first chamber 20 is disposed between the first
and second foraminous members 16 and 18. A first combustible fluid
collection chamber, being an oxygen collection chamber 22 is disposed
between the first foraminous member 16 and the first electrode 12 and a
second combustible fluid collection chamber, being a hydrogen collection
chamber 24 is disposed between the second foraminous member 18 and the
second electrode 14.
The first chamber 20 has two inlets 26 for allowing electrolytic solution to
pass into the first chamber 20. The oxygen and hydrogen collection
chambers 22 and 24 are each provided with a combustible fluid outlet. The
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oxygen coilection chamber 22 is provided with an oxygen outlet 23 and a
hydrogen collection chamber 24 is provided with a hydrogen outlet 30.
The first and second foraminous members 16 and 18 defining the first
chamber 20 forms a set of foraminous members. The apparatus 10 includes
a plurality of sets of foraminous members arranged and connected to one
another in a back-to-back arrangement. Figures 2 and 3 shows the apparatus
including 4 sets of foraminous members between the first and second
outer electrodes 12 and 14.
The apparatus includes a plurality of intermediate floating electrodes 42,
positioned between adjacent sets of foraminous members.
The electrolysing apparatus 10 further includes a plurality of first gaskets
32
and a plurality of second gaskets 34. The first gasket 32 is positioned in the
peripheral region and between the first and second foraminous members 16
and 18 to seal the two members 16 and 18 to one another and the second
gasket 34 is positioned in the peripheral region between adjacent sets of
foraminous members, surrounding the intermediate electrode 42.
The foraminous members 16 and 18 are made of polypropylene so that they
are inert, non-conductive and non-reactive. Each foraminous member 16 and
18 includes a centre portion 16.1 and 18.1 respectively, each defining
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approximately 200 holes therein and an outer boundary 16.2 and 18.2
respectively, each defining the inlets 26 and outlets 28 and 30. Each hole
defined by the centre portion 16,1 and 18.1 of the foraminous members 16
and 18 has a diameter of approximately from 0.1 mm to 3 mm, particularly
approximately 1 mm. Each foraminous member 16 and 18 is further provided
with spacing means 36 on their faces to space the foraminous members 16
and 18 from each other and from the adjacent electrode 12, 14 or 42.
The first and second electrodes 12 and 14 are made of a conductive
material, such as stainless steel, and both include a connector 38 on their
respective outer faces, for connecting to a power supply (not shown). The
powers supply thus supplies a voltage of between 1 V and 6 V, preferably 3
V over the electrolysing apparatus 10 to electrolyse the solution. The
intermediate electrodes 42 are also made of a conductive material, such as
stainless steel.
The first and second electrodes 12 and 14 and the first and second
foraminous members 16 and 18 are all disc shaped, so that the apparatus 10
is cylindrical in shape. The apparatus 10 has a diameter of approximately
250 mm with the diameter of the first and second foraminous members 16
and 18 being approximately 250 mm. The first and second foraminous
members 16 and 18 are located approximately 4 mm apart from one another,
with the first electrode 12 located at a distance of approximately 2 mm from
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the first foraminous member 16. Similarly, the second electrode 14 is located
approximately 2 mm from the second foraminous member 18.
Corresponding inlets 26 of the foraminous members of the apparatus 10 are
aligned to define inlet passages 44, so that electrolytic solution is passed
into
all of the first chambers of the apparatus 10 via the inlet passages 44. The
oxygen outlets 28 are also aligned to define an oxygen outlet passage 46, so
that oxygen produced in all of the oxygen collection chambers 22 passes out
via the oxygen outlet passage 46. Similarly, the hydrogen outlets 30 are also
aligned to define a hydrogen outlet passage 48, so that hydrogen produced
in all of the hydrogen collection chambers 24 passes out via the hydrogen
outlet passage 48.
The apparatus 10 further includes a circulating means, such as a pump (not
shown) to circulate the solution through the apparatus 10. The electrolytic
solution flowing into the first chamber 20 via the inlets 26 is pressurised by
being pumped into the apparatus 10 by the pump, so that the solution is
forced through the holes in the foraminous members 16 and 18 into the
hydrogen and oxygen collection chambers 22 and 24. The arrangement is
such that electrolytic solution flows into the first chamber 20 via the inlets
26,
through the holes of both foraminous members 16 and 18 into the oxygen
and hydrogen collection chambers 22 and 24 respectively, where electrolytic
separation takes place. The oxygen passes out of the oxygen collection
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chamber 22 via the oxygen outlet 28 and the hydrogen passes out of the
hydrogen collection chamber 24 via the hydrogen outlet 30.
The apparatus 10 further includes a hydrogen collection container (not
5 shown) connected to the hydrogen outlet passage 48 and an oxygen
collection container (also not shown) connected to the oxygen outlet passage
46. The oxygen and hydrogen collection containers each have a second
electrolytic solution outlet located towards the operatively bottom end of the
containers and oxygen and hydrogen gas outlets located towards the
10 operatively top end of each of the oxygen and hydrogen collection
containers, respectively. Electrolytic solution passes out of the oxygen and
hydrogen outlets 28 and 30 from the oxygen and hydrogen collection
chambers 22 and 24, together with the respective gases, into the oxygen and
hydrogen collection containers via the outlet passages 46 and 48. The
15 arrangement is such that hydrogen and oxygen gasses passing into the
respective containers are passed out of the containers via the oxygen and
hydrogen gas outlets and the electrolytic solution passes out of the
containers via the second electrolytic solution outlets. The second
electrolytic
solution outlets are connected to the inlet passages 44 and the solution is
circulated back to the apparatus 10 by means of the pump.
It is foreseen that there is a positive flow from the first chamber 20 to the
oxygen and hydrogen collection chambers 22 and 24 of the :ipparates 10.
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The pressurised flow of the electrolytic solution from the first chamber 20 to
the oxygen and hydrogen collection chambers 22 and 24, through the holes,
restricts oxygen gas, after formation on the first electrode (anode) 12, and
hydrogen gas, after formation of the second electrode (cathode) 14, to enter
the first chamber 20.
It is further foreseen that the hydrogen ions and electrons migrate back
through the first and second foraminous members 16 and 18 to the second
electrode (cathode) 14 where it recombines to form hydrogen.
It will be appreciated that variations in detail are possible with a method
and
apparatus for producing and separating combustible gasses according to the
invention without departing from the scope of the appended claims. For
example, the amount of holes in the foraminous member may vary and they
could have different sizes. Furthermore, the size of the cell and the
apparatus, as well as the spacing between the foraminous members and
electrodes could also vary. The apparatus 10 could further include any
number of sets of foraminous members and intermediate floating electrodes
42, depending on the voltage supplied over the apparatus 40.
