Note: Descriptions are shown in the official language in which they were submitted.
CA 02590477 2007-05-30
Dual Voltage Electrolysis Apparatus and Method of Using Same
FIELD OF THE INVENTION
The present invention relates generally to electrolysis systems and, more
particularly, to a high efficiency electrolysis system and methods of using
same.
BACKGROUND OF THE INVENTION
Fossil fuels, in particular oil, coal and natural gas, represent the primary
sources
of energy in today's world. Unfortunately in a world of rapidly increasing
energy needs,
dependence on any energy source of finite size and limited regional
availability has dire
consequences for the world's economy. In particular, as a country's need for
energy increases,
so does its vulnerability to disruption in the supply of that energy source.
Additionally, as fossil
fuels are the largest single source of carbon dioxide emissions, a greenhouse
gas, continued
reliance on such fuels can be expected to lead to continued global warming.
Accordingly it is
imperative that alternative, clean and renewable energy sources be developed
that can replace
fossil fuels.
Hydrogen-based fuel is currently one of the leading contenders to replace
fossil
fuel. There are a number of techniques that can be used to produce hydrogen,
although the
primary technique is by steam reforming natural gas. In this process thermal
energy is used to
react natural gas with steam, creating hydrogen and carbon dioxide. This
process is well
developed, but due to its reliance on fossil fuels and the release of carbon
dioxide during
production, it does not alleviate the need for fossil fuels nor does it lower
the environmental
impact of its use over that of traditional fossil fuels. Other, less developed
hydrogen producing
techniques include (i) biomass fermentation in which methane fermentation of
high moisture
content biomass creates fuel gas, a small portion of which is hydrogen; (ii)
biological water
splitting in which certain photosynthetic microbes produce hydrogen from water
during their
metabolic activities; (iii) photoelectrochemical processes using either
soluble metal complexes
as a catalyst or semiconducting electrodes in a photochemical cell; (iv)
thermochemical water
splitting using chemicals such as bromine or iodine, assisted by heat, to
split water molecules;
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(v) thermolysis in which concentrated solar energy is used to generate
temperatures high enough
to split methane into hydrogen and carbon; and (vi) electrolysis.
Electrolysis as a means of producing hydrogen has been known and used for over
80 years. In general, electrolysis of water uses two electrodes separated by
an ion conducting
electrolyte. During the process hydrogen is produced at the cathode and oxygen
is produced at
the anode, the two reaction areas separated by an ion conducting diaphragm.
Electricity is
required to drive the process. An alternative to conventional electrolysis is
high temperature
electrolysis, also known as steam electrolysis. This process uses heat, for
example produced by
a solar concentrator, as a portion of the energy required to cause the needed
reaction. Although
lowering the electrical consumption of the process is desirable, this process
has proven difficult
to implement due to the tendency of the hydrogen and oxygen to recombine at
the technique's
high operating temperatures.
A high temperature heat source, for example a geothermal source, can also be
used as a replacement for fossil fuel. In such systems the heat source raises
the temperature of
water sufficiently to produce steam, the steam driving a turbine generator
which, in turn,
produces electricity. Alternately the heat source can raise the temperature of
a liquid that has a
lower boiling temperature than water, such as isopentane, which can also be
used to drive a
turbine generator. Alternately the heat source can be used as a fossil fuel
replacement for non-
electrical applications, such as heating buildings.
Although a variety of alternatives to fossil fuels in addition to hydrogen and
geothermal sources have been devised, to date none of them have proven
acceptable for a variety
of reasons ranging from cost to environmental impact to availability.
Accordingly, what is
needed is a new energy source, or a more efficient form of a current
alternative energy source,
that can effectively replace fossil fuels without requiring an overly complex
distribution system.
The present invention provides such a system and method of use.
SUMMARY OF THE INVENTION
The present invention provides an electrolysis system and method of using
same.
In addition to an electrolysis tank and a membrane separating the tank into
two regions, the
system includes a plurality of low voltage electrodes and a plurality of high
voltage electrodes.
**The plurality of low voltage electrodes includes at least a first and second
low voltage anode
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contained within the first region of the electrolysis tank and at least a
first and second low
voltage cathode contained within the second region of the electrolysis tank.
The plurality of
high voltage electrodes includes at least a first high voltage anode contained
within the first
region of the electrolysis tank and interposed between the first and second
low voltage anodes,
and a first high voltage cathode contained within the second region of the
electrolysis tank and
interposed between the first and second low voltage cathodes. The low voltage
applied to the
low voltage electrodes is pulsed as is the high voltage applied to the high
voltage electrodes, the
low voltage pulses and the high voltage pulses being timed to occur
simultaneously. Preferably
the liquid within the tank is comprised of one or more of; water, deuterated
water, tritiated water,
semiheavy water, heavy oxygen water, and/or any other water containing an
isotope of either
hydrogen or oxygen.
Preferably the low and high voltage pulses occur at a frequency between 50 Hz
and 1 MHz, and more preferably at a frequency between 100 Hz and 10 kHz.
Preferably the low
and high voltage pulses have a pulse duration of between 0.01 and 75 percent
of the time period
defined by the frequency, and more preferably with a pulse duration of between
1 and 50 percent
of the time period defined by the frequency. Preferably the ratio of the high
voltage to the low
voltage is at least 5:1, more preferably within the range of 5:1 to 100:1,
still more preferably
within the range of 5:1 to 33: l, and still more preferably within the range
of 5:1 to 20:1.
Preferably the low voltage is between 3 and 1500 volts, more preferably
between 12 and 750
volts. Preferably the high voltage is between 50 volts and 50 kilovolts, more
preferably between
100 volts and 5 kilovolts. The low voltage electrodes and the high voltage
electrodes are
fabricated from any of a variety of materials, although preferably the
electrode material is
selected from the group consisting of stainless steel, titanium, copper, iron,
cobalt, steel,
manganese, zinc, nickel, platinum, palladium, carbon, graphite, carbon-
graphite, and alloys of
these materials and alloys thereof. The low voltage electrodes and the high
voltage electrodes
can utilize any of a variety of surface shapes, with each pair of electrodes,
i.e., the cathode and
anode of each pair, being either positioned parallel to one another or not
parallel to one another.
In at least one embodiment, the concentration of electrolyte in the liquid is
between 0.05 and 10 percent by weight. In at least one other embodiment of the
invention, the
concentration of electrolyte in the liquid is between 0.05 and 2.0 percent by
weight. In yet at
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least one other embodiment of the invention, the concentration of electrolyte
in the liquid is
between 0.1 and 0.5 percent by weight.
In at least one embodiment, the electrolysis system is cooled. Cooling is
preferably achieved by thermally coupling at least a portion of the
electrolysis system to a
portion of a conduit containing a heat transfer medium. The conduit can
surround the
electrolysis tank, be integrated within the walls of the electrolysis tank, or
be contained within
the electrolysis tank.
In at least one embodiment, the electrolysis system also contains a system
controller. The system controller can be used to perform system optimization,
either during an
initial optimization period or repeatedly throughout system operation.
A further understanding of the nature and advantages of the present invention
may be realized by reference to the remaining portions of the specification
and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an illustration of an exemplary embodiment of the invention;
Fig. 2 is an illustration of an alternate exemplary embodiment utilizing
multiple
pairs of low voltage electrodes;
Fig. 3 is an illustration of an alternate exemplary embodiment utilizing
multiple
pairs of high voltage electrodes;
Fig. 4 is an illustration of an alternate exemplary embodiment utilizing
multiple
pairs of low voltage electrodes and multiple pairs of high voltage electrodes;
Fig. 5 is an illustration of an alternate exemplary embodiment utilizing a
horizontal cylindrical tank;
Fig. 6 is an illustration of an alternate exemplary embodiment utilizing a
horizontal cylindrical tank and a separation membrane running lengthwise in
the tank;
Fig. 7 is an illustration of one mode of operation;
Fig. 8 is an illustration of an alternate mode of operation that includes
initial
process optimization steps;
Fig. 9 is an illustration of an alternate, and preferred, mode of operation in
which
the process undergoes continuous optimization; and
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Fig. 10 is an illustration of an exemplary embodiment based on the embodiment
of Fig. 1, except for the inclusion of a system controller.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
Fig. I is an illustration of an exemplary embodiment of the invention.
Electrolysis system 100 includes a tank 101 comprised of a non-conductive
material, the size of
the tank depending primarily upon the desired output of the system as well as
the dimensions of
the electrodes contained within the tank. Although tank 101 is shown as having
a rectangular
shape, it will be appreciated that the invention is not so limited and that
tank 101 can utilize
other shapes, for example cylindrical, square, irregularly-shaped, etc. Tank
101 is substantially
filled with liquid 103. In at least one preferred embodiment, liquid 103 is
comprised of water
with an electrolyte, the electrolyte being either an acid electrolyte or a
base electrolyte.
Exemplary electrolytes include potassium hydroxide and sodium hydroxide. The
term "water"
as used herein refers to water (H2O), deuterated water (deuterium oxide or
D2O), tritiated water
(tritium oxide or T20), semiheavy water (HDO), heavy oxygen water (H21S0 or
HZ17O) or any
other water containing an isotope of either hydrogen or oxygen, either singly
or in any
combination thereof (for example, a combination of H2O and D2O).
A typical electrolysis system used to decompose water into hydrogen and oxygen
gases utilizes relatively high concentrations of electrolyte. The present
invention, however, has
been found to work best with relatively low electrolyte concentrations,
thereby maintaining a
relatively high initial water resistivity. Preferably the water resistivity
prior to the addition of an
electrolyte is on the order of I to 28 megohms. Preferably the concentration
of electrolyte is in
the range of 0.05 percent to 10 percent by weight, more preferably the
concentration of
electrolyte is in the range of 0.05 percent to 2.0 percent by weight, and
still more preferably the
concentration of electrolyte is in the range of 0.1 percent to 0.5 percent by
weight.
Separating tank 101 into two regions is a membrane 105. Membrane 105 permits
ion/electron exchange between the two regions of tank 101 while keeping
separate the oxygen
and hydrogen bubbles produced during electrolysis. Maintaining separate
hydrogen and oxygen
gas regions is important not only as a means of allowing the collection of
pure hydrogen gas and
pure oxygen gas, but also as a means of minimizing the risk of explosions due
to the inadvertent
recombination of the two gases. Exemplary materials for membrane 105 include,
but are not
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limited to, polypropylene, tetrafluoroethylene, asbestos, etc. In at least one
embodiment,
membrane 105 is 25 microns thick and comprised of polypropylene.
As noted herein, the present system is capable of generating considerable
heat.
Accordingly, system components such as tank 101 and membrane 105 that are
expected to be
subjected to the heat generated by the system must be fabricated from suitable
materials and
designed to indefinitely accommodate the intended operating temperatures as
well as the internal
tank pressure. For example, in at least one preferred embodiment the system is
designed to
operate at a temperature of approximately 90 C at standard pressure. In an
alternate exemplary
embodiment, the system is designed to operate at elevated temperatures (e.g.,
100 C to 150 C)
and at sufficient pressure to prevent boiling of liquid 103. In yet another
alternate exemplary
embodiment, the system is designed to operate at even higher temperatures
(e.g., 200 C to 350
C) and higher pressures (e.g., sufficient to prevent boiling). Accordingly, it
will be understood
that the choice of materials (e.g., for tank 101 and membrane 105) and the
design of the system
(e.g., tank wall thicknesses, fittings, etc.) will vary, depending upon the
intended system
operational parameters (primarily temperature and pressure).
Other standard features of electrolysis tank 101 are gas outlets 107 and 109.
As
hydrogen gas is produced at the cathode and oxygen gas is produced at the
anode, in the
exemplary embodiment shown in Fig. I oxygen gas will exit tank 101 through
outlet 107 while
hydrogen gas will exit through outlet 109. Replenishment of liquid 103 is
preferably through a
separate conduit, for example conduit 111. In at least one embodiment of the
invention, another
conduit 113 is used to remove liquid 103 from the system. If desired, a single
conduit can be
used for both liquid removal and replenishment. It will be appreciated that
the system can either
be periodically refilled or water and electrolyte can be continuously added at
a very slow rate
during system operation.
The electrolysis system of the invention uses two types of electrodes, one
comprised of low voltage electrodes and the other comprised of high voltage
electrodes. The
low voltage electrodes include at least two low voltage cathodes and at least
two low voltage
anodes. The high voltage electrodes include at least one high voltage cathode
interposed
between the at least two low voltage cathodes and at least one high voltage
anode interposed
between the at least two low voltage anodes. All cathodes, regardless of the
type, are kept in one
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region of tank 101 while all anodes, regardless of the type, are kept in the
other tank region, the
two tank regions separated by membrane 105.
The low voltage electrodes, more specifically low voltage cathodes 115 and 117
and low voltage anodes 119 and 121, are coupled to a low voltage source 123.
The high voltage
electrodes, more specifically high voltage cathode 125 and high voltage anode
127, are coupled
to a high voltage source 129. As described and illustrated, voltage source 119
is referred to and
labeled as a'low' voltage source not because of the absolute voltage produced
by the source, but
because the output of voltage source 123 is maintained at a lower output
voltage than the output
of voltage source 129. Preferably and as shown, the individual electrodes of
each pair of
electrodes are parallel to one another; i.e., the faces of low voltage
electrodes 115, 117, 119 and
121 are parallel to one another and the faces of high voltage electrodes 125
and 127 are parallel
to one another. It should be understood, however, that the faces of the
electrodes do not have to
be parallel to one another.
In a preferred embodiment, all of the electrodes are comprised of titanium. In
another preferred embodiment, all of the electrodes are comprised of stainless
steel. It should be
appreciated, however, that other materials can be used and that the same
material does not have
to be used for both the low voltage and the high voltage electrodes, nor does
the same material
have to be used for both the low voltage anodes and the low voltage cathodes,
nor does the same
material have to be used for both the high voltage anode(s) and the high
voltage cathode(s). In
addition to titanium and stainless steel, other exemplary materials that can
be used for the low
voltage electrodes and the high voltage electrodes include, but are not
limited to, copper, iron,
cobalt, steel, manganese, zinc, nickel, platinum, palladium, carbon, graphite,
carbon-graphite,
and alloys of these materials. Preferably the surface area of each of the
faces of the low voltage
electrodes (i.e., electrodes 115, 117, 119 and 121 in Fig. 1) is a large
percentage of the cross-
sectional area of tank 101, typically on the order of at least 40 percent of
the cross-sectional area
of tank 101, and often between approximately 70 percent and 90 percent of the
cross-sectional
area of tank 101. Preferably the separation between the closest low voltage
electrodes
positioned on either side of membrane 105, i.e., electrodes 115 and 119 in
Fig. 1, is between 2
millimeters and 15 centimeters.
As previously noted, the high voltage cathode (or cathodes) is positioned
between
at least one pair of low voltage cathodes and the high voltage anode (or
anodes) is positioned
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between at least one pair of low voltage anodes. Thus in the exemplary
embodiment shown in
Fig. 1, high voltage cathode 125 is positioned between low voltage cathodes
115 and 117, and
high voltage anode 127 is positioned between low voltage anodes 119 and 121.
The high
voltage electrodes (e.g., electrodes 125 and 127) may be larger, smaller or
the same size as the
low voltage electrodes (e.g., electrodes 115, 117, 119 and 121).
As previously noted, the voltage applied to the high voltage electrode (e.g.,
electrodes 125 and 127) is greater than that applied to the low voltage
electrodes (e.g., electrodes
115, 117, 119 and 121). Preferably the ratio of the high voltage to the low
voltage is at least 5:1,
more preferably the ratio is between 5:1 and 100:1, still more preferably the
ratio is between 5:1
and 33:1, and even still more preferably the ratio is between 5:1 and 20:1.
Typically the high
voltage generated by source 129 is within the range of 50 volts to 50
kilovolts, and preferably
within the range of 100 volts to 5 kilovolts. Typically the low voltage
generated by source 123
is within the range of 3 volts to 1500 volts, and preferably within the range
of 12 volts to 750
volts.
Rather than continually apply voltage to the electrodes, sources 123 and 129
are
pulsed, preferably at a frequency of between 50 Hz and 1 MHz, and more
preferably at a
frequency of between 100 Hz and 10 kHz. The pulse width (i.e., pulse duration)
is preferably
between 0.01 and 75 percent of the time period defined by the selected
frequency, and more
preferably with a pulse width of between 1 and 50 percent of the time period
defined by the
selected frequency. Thus, for example, for a frequency of 150 Hz, the pulse
duration is
preferably in the range of 0.67 microseconds to 5 milliseconds, and more
preferably in the range
of 66.7 microseconds to 3.3 milliseconds. Alternately, for example, for a
frequency of 1 kHz,
the pulse duration is preferably in the range of 0.1 microseconds to 0.75
milliseconds, and more
preferably in the range of 10 microseconds to 0.5 milliseconds. The frequency
and/or pulse
duration can be changed during system operation, thus allowing the system
output efficiency
(i.e., heat production efficiency) to be continually optimized. Voltage is
simultaneously applied
to electrodes 125/127 from source 129 and electrodes 115/117/119/121 from
source 123. In
other words, the pulses applied to the high voltage electrodes (e.g.,
electrodes 125 and 127 in
Fig. 1) coincide with the pulses applied to the low voltage electrodes (e.g.,
electrodes 115, 117,
119 and 121). Although voltage sources 123 and 129 can include internal means
for pulsing the
respective outputs from each source, preferably an external pulse generator
131 controls a pair of
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switches, i.e., a low voltage switch 133 and a high voltage switch 135 which,
in turn, control the
output of voltage sources 123 and 129 as shown, and as described above. Other
means for
pulsing the voltage sources are clearly envisioned, for example using
switching power supplies
coupled to an external pulse generator or using switching power supplies with
internal pulse
generators. If multiple pulse generators are used, for example one pulse
generator coupled to the
low voltage source and a second pulse generator coupled to the high voltage
source, preferably
means such as a system controller are used to insure that the pulses generated
by the individual
pulse generators are simultaneous.
As described herein, the electrolysis process of the invention generates
considerable heat. It will be appreciated that if the system is allowed to
become too hot for a
given pressure, the fluid within tank 101 will begin to boil. Additionally,
various system
components may be susceptible to heat damage. Although the system can be
turned off and
allowed to cool when the temperature exceeds a preset value, for example using
a control system
coupled to a thermocouple or other heat monitor which triggers the control
system when the
system (or tank fluid) exceeds the preset value, this is not a preferred
approach due to the
inherent inefficiency of stopping the process, allowing the system to cool,
and then restarting the
system. A more efficient, and preferred, approach uses means which actively
cool the system to
maintain the temperature within an acceptable range. In at least one preferred
embodiment, the
cooling system does not allow the temperature to exceed 90 C. Although it
will be appreciated
that the invention is not limited to a specific type of cooling system or a
specific implementation
of the cooling system, in at least one embodiment tank 101 is surrounded by
coolant conduit
137, portions of which are shown in Figs. 1-6 and 10. Within coolant conduit
137 is a heat
transfer medium, for example water. Coolant conduit 137 can either surround a
portion of the
electrolysis tank as shown, or be contained within the electrolysis tank, or
be integrated within
the walls of the electrolysis tank. The coolant pump and refrigeration system
is not shown in the
figures as cooling systems are well known by those of skill in the art.
As will be appreciated by those of skill in the art, there are numerous minor
variations of the system described herein and shown in Fig. 1 that will
function substantially the
same as the disclosed system. As previously noted, alternate configurations
can utilize
differently sized/shaped tanks, different electrolytic solutions, and a
variety of different electrode
configurations and materials. Additionally the system can utilize a range of
input powers,
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frequencies and pulse widths (i.e., pulse duration). In general, the exact
configuration depends
upon the desired output as well as available space and power. Figs. 2-6
illustrate a few alternate
configurations, including the use of multiple sets of low voltage electrodes
(e.g., Fig. 2),
multiple sets of high voltage electrodes (e.g., Fig. 3), multiple sets of low
voltage and high
voltage electrodes (e.g., Fig. 4), and horizontal cylindrical tanks (e.g.,
Figs. 5 and 6).
Fig. 2 illustrates an alternate embodiment of the system shown in Fig. 1, the
alternate configuration replacing low voltage electrode 115 with four low
voltage electrodes
201-204, replacing low voltage electrode 117 with four low voltage electrodes
205-208,
replacing low voltage electrode 119 with four low voltage electrodes 209-212,
and replacing low
voltage electrode 121 with four low voltage electrodes 213-216. Note that in
Fig. 2, membrane
105 hides all but a small portion of electrode 211 and all of electrode 212.
Fig. 3 illustrates an alternate embodiment of the system shown in Fig. 1, the
alternate configuration replacing high voltage electrode 125 with two high
voltage electrodes
301-302 and replacing high voltage electrode 127 with two high voltage
electrodes 303-304.
Fig. 4 illustrates an alternate embodiment of the system shown in Fig. 1, the
alternate configuration replacing low voltage electrode 115 with four low
voltage electrodes
401-404, replacing low voltage electrode 117 with four low voltage electrodes
405-408,
replacing low voltage electrode 119 with four low voltage electrodes 409-412,
replacing low
voltage electrode 121 with four low voltage electrodes 413-416, replacing high
voltage electrode
125 with two high voltage electrodes 417-418 and replacing high voltage
electrode 125 with two
high voltage electrodes 419-420. Note that in Fig. 4, membrane 105 hides all
but a small portion
of electrode 411 and all of electrode 412.
Fig. 5 illustrates an alternate embodiment of the system shown in Fig. 1, the
alternate configuration replacing tank 101 with a horizontally configured
cylindrical tank 501,
replacing membrane 105 with an appropriately shaped membrane 503, replacing
low voltage
electrode 115 with disc-shaped low voltage electrode 505, replacing low
voltage electrode 117
with disc-shaped low voltage electrode 507, replacing low voltage electrode
119 with disc-
shaped low voltage electrode 509, replacing low voltage electrode 121 with
disc-shaped low
voltage electrode 511, replacing high voltage electrode 125 with disc-shaped
high voltage
electrode 513, and replacing high voltage electrode 127 with disc-shaped high
voltage electrode
515.
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Fig. 6 illustrates an alternate embodiment of the system shown in Fig. 1, the
alternate configuration replacing tank 101 with a horizontally configured
cylindrical tank 601
which utilizes a lengthwise membrane 603. Additionally, low voltage electrode
115 is replaced
with low voltage electrode 605, low voltage electrode 117 is replaced with low
voltage electrode
607, low voltage electrode 119 is replaced with low voltage electrode 609, low
voltage electrode
121 is replaced with low voltage electrode 611, high voltage electrode 125 is
replaced with high
voltage electrode 613, and high voltage electrode 127 is replaced with high
voltage electrode
615.
It should be understood that the present invention can be operated in a number
of
modes, the primary differences between modes being the degree of process
optimization used
during operation. For example, Fig. 7 illustrates one method of operation
requiring minimal
optimization. As illustrated, initially the electrolysis tank is filled with
liquid, e.g., water (step
701). Assuming the use of an electrolyte as preferred, the electrolyte can
either be mixed into
the water prior to filling the tank or after the tank is filled. The frequency
of the pulse generator
is then set (step 703) as well as the pulse duration (step 705). The initial
voltage settings for the
low voltage power supply (e.g., source 123) and the high voltage power supply
(e.g., source 129)
are also set (step 707), although it will be appreciated that the order of set-
up, i.e., steps 703-707,
is clearly not critical to the electrolysis process. Once set-up is complete,
electrolysis is initiated
(step 709) and continues (step 711) until the process is terminated (step
713).
After process termination, electrolysis can be re-initiated when desired.
Prior to
electrolysis re-initiation, the water can be removed from the tank (step 715)
and the tank refilled
(step 717). Prior to refilling the tank, a series of optional steps can be
performed. For example,
the tank can be washed out (optional step 719) and the electrodes can be
cleaned, for example to
remove oxides, by washing the electrodes with diluted acids (optional step
721). Spent, or used
up, electrodes can also be replaced prior to refilling (optional step 723).
The above sequence of processing steps works best once the operational
parameters have been optimized for a specific system configuration since the
system
configuration will impact the heat production efficiency of the process and
therefore the system
output. Exemplary system configuration parameters that affect the optimal
electrolysis settings
include tank size, quantity of water, type and/or quality of water,
electrolyte composition,
electrolyte concentration, pressure, electrode size, electrode composition,
electrode shape,
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electrode configuration, electrode separation, low voltage setting, high
voltage setting, pulse
frequency and pulse duration.
Fig. 8 illustrates an alternate procedure appropriate, for example, for use
with
new, untested system configurations, the approach providing optimization
steps. Initially the
tank is filled (step 801) and initial settings for pulse frequency (step 803),
pulse duration (step
805), high voltage supply output (step 807) and low voltage supply output
(step 809) are made.
Typically the initial settings are based on previous settings that have been
optimized for a
similarly configured system. For example, assuming that the new configuration
was the same as
a previous configuration except for the composition of the electrodes, a
reasonable initial set-up
would be the optimized set-up from the previous configuration.
After the initial set-up is completed, electrolysis is initiated (step 811)
and the
output of the system is monitored (step 813), for example the rate of
temperature increase.
System optimization can begin immediately or the system can be allowed to run
for an initial
period of time (step 815) prior to optimization. The initial period of
operation can be based on
achieving a predetermined output, for example a specific rate of temperature
increase, or
achieving a steady state output (e.g., a specific temperature). Alternately
the initial period of
time can simply be a predetermined time period, for example 3 hours.
After the initial time period is exceeded, assuming that the selected approach
uses
step 815, the system output is monitored (step 817) while optimizing one or
more of the
operational parameters. Although the order of parameter optimization is not
critical, in at least
one preferred embodiment the first parameter to be optimized is pulse duration
(step 819)
followed by the optimization of the pulse frequency (step 820). Then the
voltage of the high
voltage supply is optimized (step 821) followed by the optimization of the
output voltage of the
low voltage supply (step 822). In this embodiment after optimization is
complete the
electrolysis process is allowed to continue (step 823) without further
optimization until the
process is halted, step 825. In another, and preferred, alternative approach
illustrated in Fig. 9,
optimization steps 819-822 are performed continuously throughout the
electrolysis process until
electrolysis is suspended. Alternately a subset of steps 819-822 are performed
continuously
throughout the electrolysis process.
The optimization process described relative to Figs. 8 and 9 can be performed
manually. In the preferred embodiment, however, the system and the
optimization of the system
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are controlled via a system controller such as controller 1001 shown in Fig.
10. Assuming that
controller 1001 is used to control and optimize the pulse frequency, pulse
duration, high voltage
and low voltage, system controller 1001 is coupled to the pulse generator and
the voltage
supplies as shown. If the system controller is only used to control and
optimize a subset of these
parameters, the system controller is coupled accordingly (i.e., coupled to the
pulse generator to
control pulse frequency and duration; coupled to the high voltage source to
control the high
voltage; coupled to the low voltage source to control the low voltage). In
order to allow
complete automation, preferably system controller 1001 is also coupled to a
system monitor, for
example at least one temperature monitor 1003 as shown. In at least one
preferred embodiment
system controller 1001 is also coupled to a monitor 1005, monitor 1005
providing either the pH
or the resistivity of liquid 103 within electrolysis tank 101, thereby
providing means for
determining when additional electrolyte needs to be added. In at least one
preferred embodiment
system controller 1001 is also coupled to a liquid level monitor 1007, thereby
providing means
for determining when additional liquid needs to be added to the electrolysis
tank. Preferably
system controller 1001 is also coupled to one or more flow valves 1009 which
allow water,
electrolyte, or a combination of water and electrolyte to be automatically
added to the
electrolysis system in response to pH/resistivity data provided by monitor
1005 (i.e., when the
monitored pH/resistivity falls outside of a preset range) and/or liquid level
data provided by
monitor 1007 (i.e., when the monitored liquid level falls below a preset
value).
As will be understood by those familiar with the art, the present invention
may be
embodied in other specific forms without departing from the spirit or
essential characteristics
thereof. Accordingly, the disclosures and descriptions herein are intended to
be illustrative, but
not limiting, of the scope of the invention which is set forth in the
following claims.
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