US20100236939A1

US20100236939A1 - Deep water generation of compressed hydrogen

Info

Publication number: US20100236939A1
Application number: US12/799,136
Authority: US
Inventors: John E. Menear
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-03-18
Filing date: 2010-04-19
Publication date: 2010-09-23

Abstract

A hydrogen generating vessel wherein a reduction plate generates hydrogen by electrolysis of sea water. The hydrogen generating vessel operates at deep ocean levels to provide unexpected advantages. The operating depth is not limited because the hydrogen generating vessel includes openings at or near the bottom, and no pressure differential exists across the vessel walls. Pressure inside and outside are the same, and are determined by the depth at which the hydrogen generating vessel is installed. Electrolysis, collection, and temporary storage take place in the same container. Since the hydrogen pressure is the same as the water pressure at the same depth, the hydrogen is pumped by simply opening a release valve. Operation within recommended guidelines provides a self-cleaning mechanism.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of application Ser. No. 12/381,936, entitled DEEP WATER GENERATION OF COMPRESSED HYDROGEN, which was filed on Mar. 18, 2009 by John E. Menear and is currently pending. Application Ser. No. 12/381,936 is herein incorporated by reference in its entirety. This application further claims priority to: U.S. provisional application No. 61/215,197 entitled MINIMUM VESSEL SIZE FOR DEEP WATER GENERATION OF COMPRESSED HYDROGEN, filed by John E. Menear on Apr. 30, 2009, and U.S. provisional application No. 61/271,332 entitled “CLEAN REDUCTION PLATE FOR DEEP WATER HYDROGEN GENERATION USING HIGH CURRENTS AND ELECTRODE MATERIALS THAT LIMIT BUILDUP” filed by John E. Menear on Jul. 20, 2009.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable

REFERENCE TO A MICROFICHE APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention
This invention relates to renewable energy, and particularly extraction of hydrogen from flowing conductive water with a predictable flow direction or from an ocean current. The hydrogen is produced from water by electrolysis, and the energy required for electrolysis is derived from the kinetic energy of the flowing water or ocean current.
2. Description of Related Art
It is widely accepted that renewable energy sources are needed to supplement or replace fossil fuels. Air quality, global temperature concerns, oil shortages, political concerns, as well as economics combine to make fossil fuels less attractive.
Hydrogen is the ideal renewable energy source. One major advantage is that hydrogen is portable. For example, hydrogen fueled cars already exist.
From an environmental viewpoint, hydrogen produced by electrolysis of electrically conductive water has little impact. Hydrogen combustion recreates the water from which the hydrogen was extracted.
In a large circular view, (1) water in the ocean is converted to hydrogen, (2) the hydrogen is burned to create energy, and burning creates water vapor, (3) water vapor mixes with the atmosphere, and eventually falls as rain, (4) water from the rain enters streams, and (5) the streams return to the ocean. From a chemistry viewpoint, the initial state and the final states are the same.
From an energetic viewpoint, energy from an ocean current (or other flowing current) is stored as chemical energy, and released by combustion to accomplish useful work. Energy is conserved.
Many renewable energy efforts have focused on solar and wind. This is appropriate. But both solar and wind are best applied to electrical power generation that is used at fixed locations (home, business, etc) or is added into a power grid.
Hydrogen can be used for automobiles, eliminating the need for batteries and recharging. That is, hydrogen is a mobile fuel, and can replace gasoline.
Hydrogen is environmentally preferred over batteries because the batteries are typically charged with electricity generated from fossil fuel. So, carbon dioxide still accrues with battery use.
Most of today's commercial hydrogen is derived from fragmenting hydrocarbons, and hence, is tied to fossil fuels. So, even today's hydrogen cars indirectly depend on fossil fuel, and carbon dioxide still accrues. A source of hydrogen that is not based on fossil fuel adds to the appeal of hydrogen cars.
Electrolysis of water to produce hydrogen is known in the prior art. Also, the use of ocean currents for electrolysis of water has been described.
But prior art references to ocean currents have failed to enable a practical method or apparatus for hydrogen production. Normally, prior art embodiments are directed toward generating electricity, and hydrogen production is included as a secondary application. As a consequence hydrogen production ideas are overly complex, expensive to build, or cannot be scaled up to produce commercially useful quantities.
In short, the desirability of creating hydrogen from ocean currents (or other flowing water sources) has been recognized since the 1980s. But the practical apparatus and method remained unsolved prior to this instant invention.
There are six problems with prior art proposals to create hydrogen from ocean currents.
The first problem of the prior art involves electrolysis current requirements. Practical electrolysis requires large current and energy input. It requires 2 Faradays of charge to create one gram-molecular-weight (one mole) of diatomic hydrogen gas. That one gram-molecular-weight equals 2 grams of hydrogen or roughly 22.4 liters (calculated as an ideal gas).
One Faraday of charge is 96,485 coulombs. It is equivalent to 1 ampere for 96,485 seconds.
The bottom line is that prior art proposals can be used to generate hydrogen by electrolysis, but the quantities produced are small and cannot be scaled up.
The second problem of the prior art is collection. If dedicated (and separate) collection vessels are needed to store uncompressed hydrogen after generation, system complexity and cost become prohibitive. Costs are particularly high when those separate collection vessels are positioned at sea level, where small amounts of hydrogen occupy large volumes. Pressurized vessels (relative to atmospheric pressure at sea level) must be sealed, which drives costs upward.
Floating collection pods are examples of impractical hydrogen collection vessels. Each expensive pod holds very little hydrogen.
The third problem of the prior art is compression of hydrogen gas. At sea level, hydrogen is produced at 1 atmosphere, and is uncompressed. Compression at the time of generation would minimize hydrogen volume.
Two (2) grams of hydrogen occupy roughly 22.4 liters at standard temperature and pressure (ideal gas calculation). Without compression at the time of generation, overly large (impractical) generation, collection and storage vessels are needed. A separate apparatus for compression becomes necessary if hydrogen is produced at one atmosphere of pressure. Since volume is inversely proportional to pressure, generation, collection and storage at 8-10 atmospheres would be highly advantageous. The fixed production costs are reduced at 8-10 atmospheres.
The fourth problem of the prior art is hydrogen transport. Ultimately, hydrogen from the ocean-based generating station has to be transported to a distribution (or purification) terminal. This terminal may be land-based, or the terminal could be an off-shore production ship. Using hydrogen pressure to move hydrogen through piping by expansion (without requiring a separate pump) should be available as a transportation method to either a ship or land-based terminal.
A fifth problem of the prior art involves operating personnel. On-site operators are expensive. In a preferred generating station, operating personnel are only required for periodic maintenance. Unattended operation is desirable. To accomplish this, generation equipment should be uncomplicated, reliable, and based on scientific principles as opposed to complex electrical controls. The prior art does not reduce maintenance through simplicity. Microprocessor technology is often substituted for scientific fundamentals.
A sixth problem of the prior art is that safety of marine life is not prioritized. For example, if a high-speed flow-through rotary turbine is utilized (assuming useful hydrogen production quantities were possible), marine life could become trapped, hurt, or killed.
A slow-moving turbine/propeller combination might be used, but energy capture from the ocean current is low. As a consequence, hundreds of turbines would be needed, and produced hydrogen would be expensive.
There is a need for an apparatus and associated method that extracts hydrogen from deep level seawater using ocean currents for power. Some embodiments should be capable of producing more than 1 billion standard cubic feet of hydrogen per year. With these volumes, the market for hydrogen fueled cars is supported.
The invention should overcome the six above-cited problems.
Throughout this disclosure, hydrogen production quantities are recited in liters or cubic feet, regardless of the actual hydrogen pressure. Yet the volume occupied by a gas varies inversely with pressure and varies directly with Kelvin temperature. By definition in this disclosure, produced hydrogen volumes will always mean standard liters or standard cubic feet, unless specifically stated otherwise. Standard liters or standard cubic feet represent the volume that the hydrogen gas would occupy if that hydrogen were an ideal gas at 1 atmosphere and 25 degrees centigrade.

BRIEF SUMMARY OF THE INVENTION

The core of this instant invention is a hydrogen generating vessel that operates at deep ocean levels. The pressure of the ocean is used to (1) generate hydrogen in a pre-compressed volume, (2) collect and temporarily store the hydrogen in a pre-compressed volume, and (3) pump hydrogen. Specifically, the hydrogen generating vessel is designed for repetitive filling and removal, as opposed to continuous flow-through operation. The presence of a release valve distinguishes repetitive filling and removal from continuous flow-through.
To accomplish these goals effectively, a minimum size hydrogen generating vessel, a minimum installation depth, a minimum size reduction plate, and water exchange openings are required. Each requirement is established to achieve the desired overall utility.
Specifically, the internal volume of the hydrogen generating vessel must be 42 cubic feet or greater with openings in the bottom volumetric half that allow water to enter and exit. Openings in the bottom volumetric half allow ocean pressure to compress the hydrogen gas. The minimum forty-two cubic feet size allows a self-pumping feature.
This hydrogen generating vessel must be installed deep enough to generate and collect hydrogen gas with at least two atmospheres (or greater) of pressure. This corresponds to a depth of nominally 10 meters below the ocean surface. If 90% of the upper volumetric half of the hydrogen generating vessel is disposed 10 meters (or more) below the ocean surface, this requirement of two atmospheres is considered met.
Since the instant invention is targeted for commercial utility, the reduction plate has an area of at least 4 square feet. The minimum four square feet is derived from a balance between minimum production output and maximum current flux through the reduction plate.
Ocean water is not clean, and the invention incorporates design features and guidelines to maintain a clean electrolysis (reduction) electrode. Included are (1) seawater level oscillations inside the hydrogen generating vessel, (2) sufficient hydrogen generation to provide turbulence at the reduction plate surface, and (3) materials of construction to reject attachment of living organisms.
Seawater level changes inside the hydrogen generating vessel arise from the basic operating principle, and are a natural advantage of this invention. Seawater levels lower when generated hydrogen displaces the seawater downward. When hydrogen gas is removed, seawater levels rise.
A hydrogen generation quantity of at least 1 liter (at standard temperature and pressure) per minute per square foot of electrolysis plate area is recommended to maintain a clean electrolysis (reduction) plate.
Using construction materials that reject attachment of living organisms (for example, barnacles or tubeworms) is also recommended.
To be commercially practical, the hydrogen generating vessel is powered by an apparatus that converts kinetic energy of an ocean current to electrical energy. The apparatus described produces considerably more energy than prior art mechanisms, providing that an average-sized current-catcher has an area of nine square feet or more.
A hydrogen generating station (hydrogen generating vessel, power generator, and associated components) operates unmanned for extended periods of time. This means that hydrogen costs are (1) modest fixed structural expenses, (2) and periodic maintenance costs. This leads to a very low production cost.
Objects of the invention include:
a. capture kinetic energy of an ocean current and convert it into current and voltage with electrical generators,
b. harness a sufficiently large current and energy source to generate commercially significant hydrogen quantities,
c. direct the current and voltage to a negative electrolysis (reduction) plate that is housed within a hydrogen generating vessel,
d. build a production facility wherein separate collection and storage vessels are not necessary,
e. submerge the hydrogen generating vessel under the ocean surface during operation such that hydrogen is produced at a pressure of 2 atmospheres or greater,
f. produce hydrogen in a pre-compressed state, so that production vessels can be smaller than needed for production at 1 atmosphere,
g. use hydrogen pressure within a hydrogen generating vessel (based on installation depth) to pump hydrogen or through piping to land based terminals or alternate locations,
h. collect and store initial quantities of hydrogen inside the hydrogen generating vessel,
i. design a partially self-cleaning hydrogen production station that largely operates unattended, except for periodic maintenance, and
j. respect marine life.
A central (and required) feature of this instant invention is that hydrogen generation occurs below the ocean surface, where hydrogen is generated under pressure. This feature employs two basic scientific principles to novel advantage. The first principle is that ocean pressure increases as depth increases. The second is that pressure inside a hydrogen generating vessel is the same as pressure outside the hydrogen generating vessel when inside water and outside water are not separated.
The invented hydrogen generating vessel has openings which allow the surrounding ocean water (or other flowing water) to move in and out. Because a pressure drop does not exist across the walls of the hollow container (part of the hydrogen generating vessel), the cost and complexity is minimal. Inexpensive materials and unsophisticated designs suffice.
The advantages of deep level hydrogen generation are simplicity, fewer vessels, reduced construction costs, and minimal maintenance. Production is accomplished with fewer (and smaller) structural components than otherwise needed. Fewer components mean less fixed cost and less maintenance.
Electronic control circuits, microprocessors, or printed circuit boards are optional. The instant invention works without them. In the hostile ocean environment, omitting electronic controls yields a more rugged system.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a basic hydrogen generating station. In a large scale system, multiple basic hydrogen generating stations may be combined. As shown, this generating station captures kinetic energy for flowing water at three depth levels. A hollow container surrounding the negative electrolysis plate is not shown in this view.

FIG. 2 shows the top view of a rotating disk with current catchers. Note that the current catchers capture kinetic energy from the ocean current when they travel with the direction of the current. The current catchers fold into the rotating disk when traveling against the current.

FIG. 3A shows a deep level hydrogen generating vessel as part of a hydrogen generating station. A deep level hydrogen generating vessel is a combination of a hollow container with openings at the bottom portion, a reduction plate for electrolysis, a conductive wire that originates at a generator and connects to the reduction plate, a release valve, and a means (not shown) for holding the hydrogen generating vessel under water.

FIG. 3B describes the upper volumetric half and the bottom volumetric half of a hydrogen generating vessel.

FIG. 3C shows why the minimum volume of an invented hydrogen generating vessel is at least 42 cubic feet.

FIG. 4 shows an atmospheric hydrogen generating station. A separate pumping mechanism moves hydrogen at a pressure of one atmosphere for storage, purification, or compression.

FIG. 5 shows a torque canceling embodiment that captures the energy of the ocean current with two oppositely rotating disks. This arrangement has the advantage of canceled torque such that the overall structure has minimal tendency to rotate. A figure-eight belt and two-level gear combine the energy generated by the two rotating disks.

FIG. 6 shows a support frame that holds the system components together. The support frame is stationary, and the ocean current flows through it.

FIG. 7 describes the pressure advantage of deep level hydrogen generation.

FIG. 8 shows that a separate pumping mechanism isn't required for deep level hydrogen generation. Instead, compressed hydrogen moves by expansion when a valve is opened. Excess water removal is another unexpected advantage.

FIG. 9 shows the use of one or more anchors to hold a hollow container in place at deep levels.

FIG. 10 shows cables attached to ocean floor rock with secure connectors to hold the hydrogen generating vessel in place.

FIG. 11 shows a hollow hydrogen generating vessel held at its predetermined depth by a spacing beam.

FIG. 12 diagrams the self-cleaning capability that arises from hydrogen generation at a rate of at least 1 liter of hydrogen per minute per square foot of reduction plate.

FIG. 13 diagrams the self-cleaning capability that arises from water expulsion as hydrogen is generated inside the hydrogen generating vessel.

FIG. 14 diagrams the self-cleaning capability that arises from water intake when hydrogen is removed from the hydrogen generating vessel.

DETAILED DESCRIPTION OF THE INVENTION

Ocean currents move massive volumes of water continuously, and their global routes are known. The quantity of water in motion is so large that worldwide temperatures are affected by the currents.
Some ocean currents have a velocity between 2-6 meters/second. Water is heavy (1000 kilograms per cubic meter), and the kinetic energy of the moving water represents a large untapped energy source. The destructive power of a tsunami testifies to the kinetic energy of moving water.
A unique situation exists with hydrogen generation from ocean currents. The moving water that supplies the energy for electrolysis is also the reactant for hydrogen production. No additional raw materials need to be transported to the generation site.
There is a compelling environmental-economic-political argument to utilize this worldwide resource. With a readily available hydrogen source, market acceptance of hydrogen cars will be facilitated.
The volume of the earth's oceans is roughly 10,000,000 times larger than the volume of the earth's oil reserves. Far more energy is available from the oceans than from oil fields. With the current invention, the cost per Joule of hydrogen energy is lower than the cost of equivalent oil energy.
Following is an estimated cost calculation for hydrogen energy with the instant invention. It is provided only as an index to the economic viability of the instant invention. The inventive principle is not limited by these cost calculations, and it is understood that costs for a generation station will vary widely based on details (total output, location, details of construction, construction contractor costs, efficiencies, modifications, etc.)
In this calculation, a one-time structural investment is amortized across 25 years. Hence, a $10,000,000 structural cost contributes $400,000 per year. Periodic maintenance is projected at $600,000 per year. Estimating a hydrogen output of 1 billion cubic feet of hydrogen (at standard temperature and pressure) per year, the cost per cubic foot is estimated at 0.1 cent.
One gallon of gasoline can be replaced with 360 standard cubic feet of hydrogen. Based on 0.1 cent per cubic foot, that one gallon of gasoline can be replaced with 36 cents of raw produced hydrogen. Doubling the raw hydrogen cost (to account for further purification and transportation) leads to 72 cents.
In short, 72 cents of hydrogen replaces 1 gallon of gasoline. If gasoline prices increase to $7.20 per gallon, the consumer would save 90% by switching to a liquid hydrogen vehicle. Hence, the switch to hydrogen is driven entirely by the free market. Environmental benefits are a bonus.
A low energy cost structure lays the foundation to solve several recognized economic-environmental-political problems simultaneously. For example, if hydrogen production from this invention were developed on a large scale, hydrogen-fueled cars become practical. In turn, (a) the auto industry could reinvent itself with a very profitable hydrogen business model, (b) trade imbalances from oil imports would drop as hydrogen replaces gasoline, and (c) carbon dioxide emission would drop.
An unexpected self-cleaning advantage occurs when hydrogen is generated at a rate of 1 liter per minute per square foot of reduction plate. Because hydrogen is moving away from the reduction plate at a rate of roughly 1 liter/minute-square foot, surrounding ocean water moves toward the reduction plate at the same rate. Momentum of the incoming water creates a scrubbing action near the plate surface.
Within a practical range, higher hydrogen generation per square foot creates even better scrubbing since hydrogen moves away from the reduction plate at higher linear velocity. But there is an upper limit to the hydrogen generation per square foot due to current flux at the reduction plate and to liquid/solid contact, and a minimum 4-square-foot reduction plate is proposed.
In all embodiments, electrolysis is performed more than 10 meters below the surface of the ocean, where ocean pressure is nominally two atmospheres. Deeper levels (deeper than 10 meters) are even better since compression and pumping capability are both improved. Higher pressure inherently exists at deeper levels, and using the available higher pressure is a logical choice.
FIG. 1 shows a basic hydrogen production station 1. It includes one or more rotating disks 2 that rotate due to current catchers 3. Open current catchers 3 are held open by restraints 4 that hold the current catchers 3 open only in one direction. When the restraints 4 are on the downstream side of the current catchers 3, the current catchers open, and are pushed by the ocean current 5. When the restraints 4 are on the upstream side of the current-catchers, the current catchers fold. Current catchers are not pushed by the ocean current 5 when they are folded. The result is a counter-clockwise rotation 6 when viewed from the top. Note that the ocean current 5 itself opens and folds the current catchers. No complex mechanism is needed. At the start of energy capture, the ocean current 5 pushes the current catcher 3 open. At the end of energy capture, the ocean current 5 folds the current catcher 3.
The restraints 4 shown in FIG. 1 are implemented as structural blocks with sufficient rigidity and size to stabilize the open current-catchers 3. The restraints 4 operate in conjunction with the moveable joints 7 that join the current-catchers 3 to the rotating disks 2. Note that forces on the restraint 4 can be very large. If an open current-catcher 3 has an area of 100 square meters, and the ocean current is flowing at 5 meters/second, the mass of water pushing the open current-catcher 3 is roughly 500,000 kilograms per second. Furthermore, the forces behind an open current-catcher 3 (as shown) exert a mechanical advantage relative to the restraint 4 due to a greater distance from the rotating shaft 11.
In practical applications, the current-catchers have a large cross sectional area. The proposed cross sectional area of an average current catcher at a hydrogen generating station is at least 9 square meters. Forces pushing the current catchers are roughly proportional to the cross sectional area. (Force is the product of flowing water pressure and area.)
The current-catchers move at ocean current velocity. Hence, marine life is not threatened because they are drifting at the same velocity. High torque allows a high gear ratio. The generator 12 rotates quickly, even though the current-catchers 3 move slowly.
The current catchers 3, restraints 4, and moveable joints 7 shown in FIG. 1 may be replaced with more complex mechanisms if desired without affecting the inventive concept. Greater complexity may be useful to control opening and folding times, or to increase structural strength. As shown, the rotating shaft 11 is vertical rather than horizontal. This has the advantage that the current-catchers remain supported by the weight of water displaced at all times. But other orientations may be functional.
Rotating disks 2 drive the rotating shaft 11 which turns the generator 12. Voltage and electrical current from the generator 12 are connected to the reduction plate 9 and the oxidation plate 10 through conductive wires 8. Hydrogen gas is created by reduction of hydrogen in water. This is the significant reaction.
Simultaneously, oxidation of dissolved organics or anions occurs at the oxidation plate 10. The species which is oxidized is not the significant reaction for this instant application.
As shown in FIG. 1, the generator 12 is rectified. Rectification is useful so that oxygen doesn't mix with the produced hydrogen. However, rectification isn't always required. Alternating current has application to electrolysis of water.
A hollow container, which surrounds the reduction plate 9, is not shown in FIG. 1.
The conductive wires 8 (and connectors 8A) are thoroughly insulated and water-proofed to prevent electrolysis from occurring along the conductive wires 8 themselves and to prevent power losses due to shorting.
Connectors 8A to the electrolysis plates are also sealed. Without connector sealing, ocean pressure at the connectors 8A (that are disposed deep within the ocean) would push sea water upward through the insulated conductive wires 8 toward the ocean surface (where the generator is attached).
It should be noted that the apparatus in FIG. 1 does not generate electricity with the intention of connecting to an electrical grid. So, filtering, noise control, amplitude control, or synchronizing to a 60 hertz grid is not required. Costs are reduced by omitting them. The generator's 12 output requirement is production of high current above the ocean water electrolysis voltage threshold.
FIG. 2 shows a top view of a rotating disk 2 that is rotating in the counter-clockwise direction 6. The open current catchers 3 are held open by the restraints 4, capture energy from the ocean current 5, and force rotation in the counter-clockwise direction 6. The folded current catchers 3 assume a low profile as they move into the ocean current. In this way, the folded current catchers 3 contribute minimal counter-productive drag as they move toward the re-opening position.
As drawn in FIG. 2, the current catchers 3 have a curvature that approximates the outer circumference of the rotating disk 2. A curvature isn't required, but curvature has advantages for both the open and folded current catcher 3 orientations. The folded current catchers 3 lie very close to the rotating disk 2, and offer minimal resistance to the ocean current 5. The open current catchers 3 effectively capture the ocean current 5.
FIG. 2 shows that the restraints 4 provide a force against the current catchers 3 when they are downstream of the open current catchers 3, but not when they are upstream of the folded current catchers 3. Opening and folding occur around the moveable joints 7, such as hinges, axial rods, ball-and-sockets. There are many options for a moveable joint 7.
FIG. 3A shows a hydrogen generating vessel 13 that is submerged. The hydrogen generating vessel 13 includes a reduction plate 9 that is immersed in seawater 14. The hollow container 13A has openings 15 in the bottom volumetric half. The entire bottom may be open. Hydrogen gas collects at the non-porous top. Because the hydrogen generating vessel 13 is located below the ocean surface 14A, the pressure of generated hydrogen is determined by the depth pressure of the ocean.
FIG. 3B divides a hydrogen generating vessel 31B into an upper volumetric half 32B and a bottom volumetric half 33B. Regardless of shape, an upper volumetric half (that 50% closest to the ocean surface) and a bottom volumetric half (that 50% closest to the ocean floor) are inherent. The terms “upper volumetric half” and “bottom volumetric half” are employed in the claims.
FIG. 3C is a table that shows why the minimum volume of an invented hydrogen generating vessel is 42 cubic feet. At various ocean depths, the minimum volume of compressed hydrogen gas pump needed to drive itself (by expansion) through a pipe is calculated. The two key considerations are (1) that the minimum length of pipe must be at least equal to the installation depth, and (2) the volume of pressurized hydrogen must expand to at least fill the pipe volume when the pressure is lowered to one atmosphere.
The calculations in FIG. 3C quickly converged on 21 cubic feet of hydrogen gas as the installation depth increased. Since the upper volumetric half of the hydrogen generating vessel is predominantly used for gas collection and storage, the 21 cubic feet was assigned to the upper volumetric half. The bottom volumetric half must also be 21 cubic feet, leading to a total minimum volume of 42 cubic feet.
FIG. 4 shows a prior art atmospheric hydrogen generation station 41 with the hydrogen generating vessel 43 (and hollow container 43A) at or above the ocean surface 14A. Because the hydrogen is generated at roughly 1 atmosphere, it is not compressed. Very little hydrogen can be generated before hydrogen must be transferred out of the hydrogen generating vessel 43. In addition, a separate pumping mechanism 44 is used to perform the transfer. Separate storage modules 18, pre-compression modules 16, and pre-purification modules 17 are necessary and costly.
Separate pumping mechanisms 44, separate storage modules 18, pre-compression modules 16, and pre-purification modules 17 are not needed with deep level hydrogen generation. That is, deep level generation significantly reduces the cost of construction and the complexity of operation.
FIG. 7 shows generation of hydrogen more than 40 meters below the ocean surface. A reference scale on the right side of FIG. 7 is incorporated to show ocean pressure versus depth. As a rule of thumb, pressure increases 1 atmosphere with each 10 meters of depth. As indicated by a dashed line, hydrogen is generated where ocean pressure is 5.3 atmospheres. As an added consideration, the temperature of the ocean at 40 meters will normally be lower than the temperature at the surface. Both factors (higher pressure and lower temperature) decrease the volume of one gram-molecular-weight of hydrogen, relative to 25 degrees C. and 1 atmosphere of pressure. Pressure is the primary compressing factor.
At 5.3 atmospheres, roughly 5.3 times more hydrogen molecules can accumulate (relative to one atmosphere) before the hydrogen has to be moved elsewhere. Hence, the hydrogen generating vessel 73 also acts as an intermediate storage container, leading to a more efficient (less complex) production flow.
In FIG. 7, the conductive wire 8 attaches to the reduction plate 79 through the bottom of the hollow hydrogen generating container 73A. Bottom entry isn't required, but it is convenient because the bottom portion of the hollow hydrogen generating container 73A is porous.
At 100 meters below the ocean surface, the compression factor for generated hydrogen is roughly eleven. The size of the overall production station is significantly reduced, and the fixed cost of the station is dramatically reduced (compared to atmospheric production).
The walls of the hollow container 73A can be conductive or static dissipative to assure that static charges do not accumulate. This may not be necessary because the ocean itself is conductive. But it serves as an additional preventative safety feature.
FIG. 8 shows a deep level hydrogen generating vessel 83 that is producing hydrogen at 8.5 atmospheres. The hollow hydrogen generating container 83A that defines the shape of the hydrogen generating vessel 83 is a domed cylinder. A conductive wire is not shown in this figure. As always, the bottom volumetric half is porous so that ocean water flows in and out. The upper volumetric half is non-porous to prevent hydrogen escape.
A release valve 84 at the top of the hydrogen generating vessel 83 eliminates the need for a separate pumping mechanism. Because the hydrogen is pressurized, relative to a land terminal at 1 atmosphere, opening the release valve 84 moves the hydrogen to the land terminal. No separate pumping mechanism is needed.
As the hydrogen moves through the piping 85 it moves upward (the land terminal is higher than the hydrogen generating vessel 83). An opportunity to remove entrained seawater exists by ensuring that some of the nearby piping 85 is positioned higher than the release valve. Twists, turns 86, rough spots, screens, or packing material 87 above the release valve 84 serve as locations for water coalescence. In addition, expansion cools and further aids in removing some of the entrained water. Agglomerated water moves backward (downward) in the piping 85.
As shown, removed water (plus dissolved salt) returns to the hydrogen generating vessel 83, and, hence, back into the ocean. No separate drain is needed. This serves as a pre-purification bonus that arises from considerate design. Transporting partially dries the hydrogen without extra effort or expense. Hence, final purification is simplified and less costly.
In this FIG. 8 embodiment, the shape of the hollow container 83A is cylindrical with a domed top. However, shape is not critical as long as hydrogen can accumulate without escape in the upper volumetric half, and the release valve 84 is above the bulk of collected hydrogen.
In this embodiment, there is an orifice in the side of the hydrogen generating vessel 83 that allows line-of-sight movement of aqueous ions between the electrolysis plate(s), which is located outside for safety reasons. This is useful for high generation rates because aqueous ion flow between reduction and oxidation plates 90 is unobstructed. This improves performance.
An optional level sensor 88 is shown in FIG. 8. In some embodiments, the sensor 88 automatically activates the release valve 84. In other embodiments, the release valve can be activated remotely. Wireless communication may be used to control the release valve. Or, the level sensor 88 and release valve 84 may be mechanically linked, and require no electronics.
FIG. 5 shows a torque canceling system 50. This is useful to prevent a tendency for the entire structure to rotate. Two rotating disks 2 are combined to cancel torque forces. Note that the two rotating shafts 51 are rotating in opposite directions so that angular momentum is roughly equal and opposite. A figure-eight belt 55 and dual-level gear 54 add the rotational energy of the two rotating shafts 51, and sum the energy to the generator 52.
It is understood that more than one generator 52 may be used, and remain within the inventive concept. For large current-catchers 3, multiple generators may be employed to convert the large amount of kinetic energy of the ocean current 5 to electrical energy. Only one generator 52 in FIG. 5 is drawn for purposes of explaining the concept.
As drawn, the generator(s) 52 is positioned near the ocean surface. This is convenient from a maintenance perspective, but isn't required. Regardless of depth, the generator 52 will be exposed to hostile conditions, and a protective enclosure is appropriate.
The restraints 4 are placed to open and fold the current-catchers 3 in opposite directions, and, hence, cause rotation in opposite directions.
FIG. 6 shows a support frame 60 that contains and stabilizes the components. Ocean current 5 flows through the porous walls 61. A skeletal frame has advantages in stormy seas since a skeletal frame allows turbulence and large waves to pass through without bending, twisting, damaging or upsetting the hydrogen generating station.
The invented deep level hydrogen generation operates with minimal human interaction. Unless maintenance is required, human presence is not needed.
The following energy estimates are included only as an aid to understanding the invention and positioning its importance. The estimates are not intended as specifications or requirements or invention limitations.
Refer back to FIG. 1. Consider an open current catcher 3 whose area is 100 square meters that captures the kinetic energy of an ocean current 5 moving at five meters per second. The available kinetic energy per second is approximately ½ mV², which is theoretically 6.3 million joules per current catcher per second (or 6.3 million Watts per current catcher).
Scaling up, six current catchers 3 acting together create 38 million Watts.
Since the electrolysis of water (in concentrated electrolyte) begins at 1.2 volts, 38 million Watts can theoretically supply current to multiple electrolysis plates at up to 32 million amps (32 million coulombs per second).
193,000 amps (two Faradays per second) will produce (at full efficiency) 1 gram-molecular-weight or 22.4 liters of diatomic hydrogen per second. By proportion, 32 million amps will produce 166 gram-molecular-weights or 3714 liters or 131 cubic feet of hydrogen per second (ideal gas at standard temperature and pressure).
At continuous generation, this equates to more than four billion cubic feet per year.
Employing 100 to 1000 hydrogen generating systems in the oceans makes hydrogen cars feasible worldwide.
Performing electrolysis at deep ocean levels simplifies the overall process, but requires structural means for holding hydrogen generating vessels at predetermined depths. Hydrogen gas weighs less than the seawater that it displaces. As hydrogen gas collects inside a hydrogen generating vessel, the hydrogen generating vessel becomes more buoyant. This has to be countered with a downward force.
It is also important to keep the top of the hydrogen generating vessels facing upward (toward the ocean surface) or hydrogen could be lost. This upward orientation is partially self-adjusting since the less dense hydrogen gas (relative to water) will seek the highest level.
FIG. 9 shows the use of one or more anchors 91 to hold a hydrogen generating vessel 93 in place. The weight of the anchor 91 is sufficient to overcome the upward buoyancy due to the hydrogen collected. In this embodiment, multiple anchors are used to further assure that the hydrogen generating vessel 93 maintains an upward orientation (top facing the surface).
In an effort to minimize the weight of the anchor 91, hydrogen may be transported from the hydrogen generating vessel 93 before large hydrogen quantities accumulate. That is, a release valve 94 can be activated more often.
The weight of the hydrogen generating vessel 93 itself acts as an anchor. Heavy metal hollow containers 93A are possible, but from a cost viewpoint may not be the best choice. Wall strength is not a primary concern. So, thin wall construction is a reasonable option.
FIG. 10 shows cables 101 connected to the ocean floor 102 or to a heavy object on the ocean floor with secure attachments 104 that hold the hydrogen generating vessel 103 in place.
FIG. 11 shows a hydrogen generating vessel 113 held at its predetermined depth by a spacing beam 111 positioned between the support frame 110 and the hollow container 113A. The cross-sectional shape of the spacing beam 111 is not important. For example, it could be linear, triangular, rectangular, square, polygon, elliptical, or equivalent.
The use of anchors, cables, and spacing beams does not comprise a comprehensive list of ways to hold a hydrogen generating vessel in place at a predetermined depth. They are examples only. Other equivalent methods are useful.
Much of the above discussion has focused on ocean currents. However, rivers, streams, and fast tidal flows can also apply this invention. For example, the San Francisco bay has deep channels and fast flows.
Ocean water is not clean. If the reduction plate becomes dirty, the efficiency of hydrogen production could suffer. To maintain efficiency, average hydrogen generation of at least 1 liter per minute per square foot at the reduction plate is suggested. At this generation rate, hydrogen is generated quickly, and provides a scrubbing action at the reduction plate surface.
FIG. 12 shows how the minimum hydrogen generation rate of 1 liter per minute per square foot at the reduction plate creates a self-cleaning turbulence. The generating surface 121 of the reduction plate 129 releases hydrogen gas bubbles 123. The hydrogen gas bubbles 123 move away from the reduction plate along an upward-and-outward gas direction line 124. As the hydrogen bubble leaves the generating surface 121, ocean water 122 moves toward the generating surface 121 along water direction line 126. The net result is turbulence 125, which functions to scrub the generating surface 121.
Note that the hydrogen flow is away from the reduction plate surface at roughly 0.4 inches per minute. This further creates a barrier for solid contaminants that might otherwise contact the reduction plate.
The minimum hydrogen generation rate of 1 liter per minute per square foot (at standard temperature and pressure) at the reduction plate suffices to provide scrubbing at a wide range of ocean depths. With shallow installations, the molar volume of hydrogen is large, and the pressure (force per unit area) of the displacing water is low. At very deep ocean levels, the molar volume of hydrogen is reduced, but the pressure of the displacing water is high. Either situation works.
Self-cleaning is augmented by continual changes of water inside the hydrogen generating vessel. FIG. 13 shows that ocean water 132 inside the hydrogen generating vessel 131 moves along the exit direction 133 during hydrogen generation. Ocean water (that previously filled the hydrogen generating vessel 131) moves relative to the stationary reduction plate 139, and returns to the ocean. Contaminants (from any source) inside the hydrogen generating vessel 131 are carried back into the ocean. Contaminants include those released by the scrubbing action of hydrogen generation.
FIG. 14 describes water movement when the hydrogen inside the hydrogen generating vessel 141 is transferred elsewhere. Ocean water 142 enters from the bottom of the hydrogen generating vessel 141, and moves past the reduction plate 149 along filling direction 143.
The in-and-out water movement shown in FIG. 13 and FIG. 14 constitutes a pumping action. Contaminants and dirt do not concentrate inside the hydrogen generating vessel.
Further self-cleaning is available through selection of reduction plate materials. Low concentrations of copper ions, silver ions, or tin ions near the reduction plate reduce the tendency for barnacles or tube worms to attach to the reduction plate (or other surfaces). The reduction plate may be metallic copper, tin or silver, or the reduction plate may be alloys of copper, tin or silver. Films or hydrolysable polymers may also be used, providing that they can accommodate high current flux. Other metallic ions (beyond copper, tin or silver) may be useful.
The combination of (a) scrubbing via turbulence and (b) frequent water exchange and (c) copper/tin/silver materials selection increases the mean time period between maintenance visits.
Although four square feet has previously been cited as the minimum acceptable reduction plate size, much larger reduction plate areas are needed for high quantity hydrogen production.
Very large hydrogen generating vessels with large reduction plates are indicated. At a hydrogen generation rate of 1 liter per minute per square foot of reduction plate, it requires 53898 square feet of reduction plate to realize 1 billion cubic feet of hydrogen per year. At a hydrogen generation rate of 10 liters per minute per square foot of reduction plate, it requires 5389.8 square feet of reduction plate to realize 1 billion cubic feet of hydrogen per year.

Claims

1. A hydrogen generating vessel wherein

hydrogen gas is produced from ocean water at a pressure of at least 2 atmospheres,

said hydrogen gas is collected and temporarily stored within said hydrogen generating vessel, and

said pressure is wholly or partially used to transport said hydrogen gas from inside said hydrogen generating vessel to another location,

comprising:

a hollow hydrogen generating container with an internal volume of at least 42 cubic feet which

possesses openings in a bottom volumetric half, through which said ocean water moves into and out of said hydrogen generating container,

includes a release valve in an upper volumetric half,

is not porous in said upper volumetric half, so that hydrogen gas does escape without opening said release valve, and

confines generated hydrogen gas between

inside surfaces of said upper volumetric half, and

a variable level of said ocean water within said hydrogen generating container;

at least one reduction plate which

is connected to a lower segment of said hydrogen generating container, and

receives current and voltage from at least one generator to electrolyze said ocean water to create said hydrogen gas; and

a means for positioning said hydrogen generating container below an ocean surface, where

ocean pressure is at least said 2 atmospheres within said upper volumetric half, or 90% of said upper volumetric half is disposed at least 10 meters below said ocean surface.

2. The hydrogen generating vessel in claim 1 wherein said ocean water within said hydrogen generating vessel is displaced downward as said hydrogen gas collects inside said hydrogen generating vessel.

3. The hydrogen generating vessel in claim 1 wherein said ocean water pressure inside said hydrogen generating vessel is equal to said ocean water pressure outside said hydrogen generating vessel.

4. The hydrogen generating vessel in claim 1 wherein a conductive cable conducts said voltage and current from said generator to said reduction plate.

5. The hydrogen generating vessel in claim 1 wherein said generator is powered by current catchers, and said generator converts kinetic energy from ocean currents to electrical energy.

6. The hydrogen generating vessel in claim 5 wherein each said current catcher has a surface area of at least nine square meters.

7. The hydrogen generating vessel in claim 5 wherein said current catchers are attached to a rotating disk, and said current catchers are

closed when moving against the direction of said ocean current, and

open when moving in the direction of said ocean current.

8. Claim 7 where said rotating disk is linked to a shaft that turns said generator.

9. Claim 7 where said rotating disk rotates around a vertical axis.

10. The hydrogen generating vessel in claim 7 wherein said generator, said current catchers, and said rotating disk are fixed to a wide area porous frame.

11. The hydrogen generating vessel in claim 1, wherein a hydrogen generation rate at said reduction plate is greater than 1 liter per minute per square foot of reduction plate surface.

12. The hydrogen generating vessel in claim 11 wherein said hydrogen generation rate further exceeds 10 liters per minute per square foot of reduction plate surface

13. The hydrogen generating vessel in claim 1 wherein said reduction plate has an area of at least 4 square feet.

14. The hydrogen generating vessel in claim 1 further comprising a section of pipe above said release valve, and said section of pipe contains screens, packing material, restrictions, rough surfaces, or turns that separate droplets of ocean water from hydrogen gas.

15. The hydrogen generating vessel in claim 1 wherein said release valve is any one of an electronic solenoid valve, a float valve, and a pressure activated valve.

16. The hydrogen generating vessel in claim 1 whereby an oxidation plate is disposed beside, rather than under or within, the enclosed volume of said hydrogen generating vessel.

17. The hydrogen generating vessel in claim 1 wherein multiple said reduction plates are separated by physical barriers within said bottom volumetric half, and the combined said hydrogen gas output is collected and stored in said upper volumetric half.

18. The hydrogen generating vessel in claim 1 wherein said means for positioning include any one selected from a group consisting of—

anchors connected to said hydrogen generating vessel,

an inherent weight of said hydrogen generating vessel,

attachment points on said hydrogen generating vessel that are connected to a stable ocean floor, and

attachment points on said hydrogen generating vessel that are connected to a pylon that is built into an ocean floor,

cables between said hydrogen generating vessel and an ocean floor, and

chains between said hydrogen generating vessel and an ocean floor.

19. The hydrogen generating vessel in claim 1 wherein said reduction plate comprises any one selected from a group consisting of metallic copper, metallic tin, metallic silver, alloys of copper, alloys of tin, alloys of silver, polymers containing copper, polymers containing tin, and polymers containing silver.

20. A method of generating, collecting, temporarily storing, and transporting hydrogen gas from ocean water with a hydrogen generating vessel that includes

a hollow hydrogen generating container with an internal volume of at least 42 cubic feet,

one or more reduction plates,

a bottom volumetric half of said hydrogen generating vessel wherein ocean water enters and exits through openings, and

an upper volumetric half of said hydrogen generating vessel wherein

collection and storage of said hydrogen gas occur, and

a release valve is disposed which is used to transport of said hydrogen gas to another location,

comprising:

installing said hydrogen generating vessel below an ocean surface such that either

ocean depth pressure inside said upper volumetric half is at least 2 atmospheres, or

90% of said upper volumetric half is disposed at least 10 meters beneath said ocean surface;

connecting at least one said reduction plate to at least one generator with a conductive cable; and

electrolyzing said ocean water to generate hydrogen gas at said reduction plate; and

compressing and collecting said hydrogen gas with said ocean water

where said ocean water pressure inside said hydrogen generating vessel increases with increasing installation depth.

21. The method of claim 20 further comprising

filling said hydrogen generating vessel with ocean water at the beginning of each hydrogen generation cycle by opening said release valve.

22. The method of claim 20 where an oxidation plate is disposed beside, rather than under or inside, the enclosed volume of said hydrogen generating vessel.

23. The method of claim 20 wherein hydrogen production is at least 1 standard liter per minute per square foot of reduction plate surface.

24. The method of claim 20 wherein hydrogen production is at least 10 standard liters per minute per square foot of reduction plate surface.

25. The method of claim 20 wherein said generator is powered by current catchers that convert kinetic energy from ocean currents to electrical energy.

26. The method of claim 25 wherein said current catchers are attached to a rotating disk, and said current catchers are

closed when moving against the direction of said ocean current, and

open when moving in the direction of said ocean current.

27. The method of claim 26 wherein said rotating disk is linked to a shaft that turns said generator.

28. The method of claim 20 wherein two said generators are employed, and said generators spin in opposite angular directions.

29. The method of claim 20 further comprising connecting said hydrogen generating vessel to an ocean floor to prevent said hydrogen generating vessel from rising toward an ocean surface.

30. The method of claim 20 wherein said ocean water level inside said hydrogen generating vessel decreases during hydrogen production and wherein said ocean water level rises during hydrogen transport, which creates a pumping action that assists in keeping said reduction plate clean.

31. The method of claim 20 wherein said installing is further performed such that 90% of said upper volumetric half is disposed at least 50 meters beneath said ocean surface.

32. The method of claim 20 wherein said installing is further performed such that 90% of said upper volumetric half is disposed at least 100 meters beneath said ocean surface.

33. The method of claim 20 wherein said installing is further performed such that 90% of said upper volumetric half is disposed at least 500 meters beneath said ocean surface.