Method and system for producing hydrogen

Abstract

A system for generating hydrogen, comprises an elongated reaction chamber configured for receiving a slurry containing water and a redox active powder and forming oppositely directed flows of the slurry, a first outlet downstream of an inner flow of the flows, for discharging a first liquid stream comprising hydrogen enriched water and suspended reduced-form particulates derived from the redox active powder in a shear layer between the flows, a second outlet downstream of a peripheral flow of the flows, for discharging a second liquid stream comprising oxygen‑enriched water and suspended oxidized‑form particulates derived from the redox‑active powder in the shear layer, and a power source configured to apply negative bias to the first outlet relative to the chamber.

Description

[0001] METHOD AND SYSTEM FOR PRODUCING HYDROGEN

[0002] RELATED APPLICATION

[0003] This application claims the benefit of priority of U. S. Provisional Patent Application No. 63 / 737,836 filed on December 23, 2025, the contents of which are incorporated herein by reference in their entirety.

[0004] FIELD AND BACKGROUND OF THE INVENTION

[0005] The present invention, in some embodiments thereof, relates to production of hydrogen and, more particularly, but not exclusively, to a method and system for producing hydrogen from a flow of liquid.

[0006] Hydrogen production spans established thermal routes and electrochemical and photochemical pathways. Industrially, large volumes are produced by reforming and gasification processes in which hydrocarbons or coal are converted to synthesis gas and then shifted to hydrogen, including steam methane reforming, autothermal reforming, partial oxidation, and coal or biomass gasification; carbon capture and storage may be applied to lower net emissions. By-product hydrogen from chlor-alkali electrolysis and refinery off-gases is also utilized where available.

[0007] Water electrolysis provides a direct route from electricity to hydrogen using alkaline cells, proton exchange membrane systems, and high-temperature solid oxide electrolysis, with operating envelopes that can be matched to grid or on-site renewable power. Emerging approaches aim to improve specific energy consumption or capital cost through advanced catalysts, membranes, and balance-of-plant integration. Low- or zero-carbon concepts include methane pyrolysis to hydrogen and solid carbon, solar-driven thermochemical cycles, photoelectrochemical and photocatalytic water splitting, and biological routes such as dark and photo-fermentation, each with development focused on durability, materials utilization, and scale-up.

[0008] SUMMARY OF THE INVENTION

[0009] According to some embodiments of the invention there is provided a system for generating hydrogen, comprising: an elongated reaction chamber configured for receiving a slurry containing water and a redox active powder and forming oppositely directed flows of the slurry; a first outlet downstream of an inner flow of the flows, for discharging a first liquid stream comprising hydrogen enriched water and suspended reduced-form particulates derived from the redox active powder in a shear layer between the flows; a second outlet downstream of a peripheral flow of the flows, fordischarging a second liquid stream comprising oxy gen-enriched water and suspended oxidized-form particulates derived from the redox-active powder in the shear layer; and a power source configured to apply negative bias to the first outlet relative to the chamber.

[0010] According to some embodiments of the invention the reaction chamber is cylindrical.

[0011] According to some embodiments of the invention the system comprises a swirling apparatus at an inlet of the reaction chamber configured to impart swirl to the flows.

[0012] According to some embodiments of the invention the flows are swirling about a common axis and have opposite mean axial components with the shear layer therebetween.

[0013] According to some embodiments of the invention the first outlet comprises a central tube aligned with a central axis of the reaction chamber.

[0014] According to some embodiments of the invention the second outlet is arranged adjacent an inner surface of the reaction chamber to receive the peripheral flow.

[0015] According to some embodiments of the invention the second outlet comprises separate outlets for venting a gaseous fraction and a mixture comprising oxidized-form particulates and water. According to some embodiments of the invention the chamber comprises an electrically conductive inner surface connected to the power source as an anode.

[0016] According to some embodiments of the invention the power source comprises a direct current source.

[0017] According to some embodiments of the invention the power source is configured to operate in a pulsed mode to modulate a potential of the first outlet relative to the reaction chamber.

[0018] According to some embodiments of the invention the system comprises a magnetic field generator arranged to apply a magnetic field to the flows.

[0019] According to some embodiments of the invention the magnetic field generator is configured to produce an axial magnetic field relative to a central axis of the reaction chamber.

[0020] According to some embodiments of the invention the magnetic field generator is configured to produce a magnetic field having a radial gradient across the shear layer.

[0021] According to some embodiments of the invention the system comprises a hydrogen gas holder in fluid communication with the first outlet and an oxygen gas holder in fluid communication with the second outlet, each configured to accumulate respective gas separated from a respective liquid stream.

[0022] According to some embodiments of the invention the system comprises a hydrogen compressor connected to the hydrogen gas holder and a hydrogen receiver connected to an outlet of the hydrogen compressor.According to some embodiments of the invention the system comprises an oxygen compressor connected to the oxygen gas holder and an oxygen receiver connected to an outlet of the oxygen compressor.

[0023] According to some embodiments of the invention a portion of water from the gas holder connected to the second outlet is directed to the gas holder connected to the first outlet.

[0024] According to some embodiments of the invention the system comprises a separator configured to separate water from oxidized-form particulates in the second liquid stream and a pump configured to return at least a portion of separated water to the reaction chamber.

[0025] According to some embodiments of the invention the system comprises a mixer-dosing device configured to form the slurry from water supplied from a source water tank and the redox active powder supplied from a sealed hopper.

[0026] According to some embodiments of the invention the system comprises an additional generator arranged upstream of the reaction chamber and configured to apply to the slurry at least one action selected from the group consisting of electrical discharge, acoustic action, electromagnetic action, thermal action, and chemical action.

[0027] According to some embodiments of the invention the additional generator comprises at least one of: an acoustic transducer coupled to a wall of the reaction chamber, an electromagnetic coil arranged around the reaction chamber, and an electrical discharge source configured to act on the slurry upstream of the reaction chamber.

[0028] According to some embodiments of the invention there is provided a method of generating hydrogen, comprising: forming within a reaction chamber having first and second outlets, oppositely directed flows of a slurry containing water and a redox active powder, with a shear layer between the flows; applying negative bias to the first outlet relative to the reaction chamber; discharging, downstream of an inner flow of the flows, through the first outlet, a first liquid stream comprising hydrogen enriched water and suspended reduced-form particulates derived from the redox active powder in the shear layer; and discharging, downstream of a peripheral flow of the flows, through the second outlet, a second liquid stream comprising oxygen-enriched water and suspended oxidized-form particulates derived from the redox-active powder in the shear layer.

[0029] According to some embodiments of the invention the flows are swirling about a common axis and have opposite mean axial components with the shear layer therebetween.

[0030] According to some embodiments of the invention the method comprises forming the flows by introducing the slurry through a swirling apparatus at an inlet of the reaction chamber.According to some embodiments of the invention the negative bias is applied by applying a direct current electric potential between the first outlet and an electrically conductive inner surface of the reaction chamber.

[0031] According to some embodiments of the invention the negative bias is applied by connecting an electrically conductive inner surface of the reaction chamber as an anode.

[0032] According to some embodiments of the invention the method comprises applying a magnetic field to the flows using a magnetic field generator arranged to apply the magnetic field.

[0033] According to some embodiments of the invention the redox active powder comprises a material selected from the group consisting of oxides and / or hydroxides of iron, manganese, cobalt, nickel, copper, vanadium, molybdenum, tungsten, or cerium, including one or more of FeO, Fe3O4, Fe2O3, Fe(OH)2, Fe(OH)3, MnO, Mn3O4, Mn2O3, MnO2, Mn(0H)2, CoO, Co3O4, NiO, Ni(0H)2, Cu2O, CuO, V2O3, VO2, V2Os, MoO2, MoO3, WO2, WO3, Ce2O3, CeO2, and mixtures thereof.

[0034] According to some embodiments of the invention the redox active powder comprises iron oxide FeO.

[0035] According to some embodiments of the invention the suspended oxidized-form particulates comprise iron(III) oxide Fe2O3and / or iron oxide Fe3O4.

[0036] According to some embodiments of the invention the second liquid stream further comprises hydrogen peroxide.

[0037] According to some embodiments of the invention the method comprises forming the slurry by mixing water from a source water tank with the redox active powder supplied from a sealed hopper in a mixer-dosing device.

[0038] According to some embodiments of the invention the method comprises collecting hydrogen separated from the first liquid stream in a hydrogen gas holder.

[0039] According to some embodiments of the invention the method comprises compressing hydrogen collected from the first liquid stream with a hydrogen compressor and storing the compressed hydrogen in a hydrogen receiver.

[0040] According to some embodiments of the invention the method comprises collecting oxygen separated from the second liquid stream in an oxygen gas holder.

[0041] According to some embodiments of the invention the method comprises compressing oxygen collected from the second liquid stream with an oxygen compressor and storing the compressed oxygen in an oxygen receiver.

[0042] According to some embodiments of the invention the method comprises separating water from oxidized-form particulates in the second liquid stream using a separator.According to some embodiments of the invention the method comprises returning at least a portion of water separated from the second liquid stream to the reaction chamber.

[0043] According to some embodiments of the invention the method comprises applying to the slurry, upstream of entering the reaction chamber, at least one action selected from the group consisting of electrical discharge, acoustic action, electromagnetic action, thermal action, and chemical action using an additional generator arranged upstream of the reaction chamber.

[0044] According to some embodiments of the invention the method comprises recirculating at least a portion of the slurry back to the reaction chamber.

[0045] According to some embodiments of the invention the method comprises directing oxidized-form particulates from the second liquid stream to a regeneration process to form the redox active powder.

[0046] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0047] Implementation of the method and / or system of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of embodiments of the method and / or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.

[0048] For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to exemplary embodiments of method and / or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and / or data and / or a non-volatile storage, for example, a magnetic hard-disk and / or removable media, for storing instructions and / or data. Optionally, a network connection is providedas well. A display and / or a user input device such as a keyboard or mouse are optionally provided as well.

[0049] BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0050] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0051] Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

[0052] In the drawings:

[0053] FIGs. 1 A and IB are schematic illustrations of a system for generating hydrogen, according to some embodiments of the present invention;

[0054] FIG. 2 is a schematic illustration showing the system in greater detail, according to some embodiments of the present invention;

[0055] FIGs. 3 A-E are schematic illustrations of an example reaction chamber which can be used in the system according to some embodiments of the present invention; and

[0056] FIG. 4 is a schematic illustration showing mechanisms that can be applied externally, according to some embodiments of the present invention.

[0057] DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

[0058] The present invention, in some embodiments thereof, relates to production of hydrogen and, more particularly, but not exclusively, to a method and system for producing hydrogen from a flow of liquid.

[0059] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and / or methods set forth in the following description and / or illustrated in the drawings and / or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

[0060] Referring now to the drawings, FIGs. 1 A and IB are schematic illustrations of a system 10 for generating hydrogen, according to some embodiments of the present invention. System 10comprises an elongated reaction chamber 12 configured for receiving a slurry containing water and a redox active powder. Typically, the slurry is received through an inlet 14. The received slurry is represented by block arrow 16.

[0061] In some embodiments of the present invention, the redox active powder suspended in water may comprise a material selected from oxides and / or hydroxides of transition or rare-earth elements, including iron, manganese, cobalt, nickel, copper, vanadium, molybdenum, tungsten, or cerium, and including one or more of FeO, Fe3O4, Fe2O3, Fe(OH)2, Fe(OH)3, MnO, M C, MmCh, MnO2, Mn(0H)2, CoO, CO3O4, NiO, Ni(0H)2, Cu2O, CuO, V2O3, VO2, V2O5, MoO2, MoO3, WO2, WO3, Ce2O3, CeCh, and mixtures, composites, or doped variants thereof. In some embodiments, the redox active powder comprises iron oxide FeO as a primary catalytic material, optionally and preferably freshly prepared or conditioned to present high surface reactivity, and may include minor fractions of other oxides to modulate redox kinetics, for example 0.1-20 wt% of Mn02, CO3O4, or NiO. In some embodiments, particle sizes may be tailored, for example with median diameters from about 10 nm to about 200 pm, such as 50 nm, 200 nm, 1 pm, 5 pm, 20 pm, or 80 pm, and particle morphology may include equiaxed grains, platelets, whiskers, porous agglomerates, or core-shell structures that include conductive or magnetic shells. In some embodiments, surface modifiers such as thin oxidehydroxide layers, oxygen vacancies, or adsorbed promoters may be present to enhance radical adsorption and redox cycling under cavitation.

[0062] Reaction chamber 12 is also configured to form oppositely directed flows of slurry 16 therein that interact across a shear layer formed between the flows.

[0063] As used herein, "oppositely directed flows" refers to two contemporaneous volumetric motions of the slurry within a common reaction volume that, when resolved along a longitudinal direction with respect to the reactor geometry, have mean velocity components of opposite sign over respective spatial sub-regions separated by an intervening shear layer. In some embodiments, the spatial sub-regions comprise an inner sub-region in which net mass flows in one direction, and a peripheral sub-region, surrounding the inner sub-region, in which net mass flows in the opposite direction. The boundary between the sub-regions may present elevated velocity gradients, interfacial mixing, and / or entrainment of suspended particulates. The oppositely directed flows may persist with unequal magnitudes, cross-sectional areas, or mass flow rates between the two directions.

[0064] In some embodiments, oppositely directed flows may include configurations in which streamlines are curved or helical and the flows swirl about a common axis, with opposite mean axial components despite similar or dissimilar azimuthal components. The flows may include steady, quasi-steady, or unsteady states; and may encompass laminar, transitional, or turbulent regimes.Oppositely directed flows, according to some embodiments of the present invention, are illustrated in FIG. IB. Shown are, an outer peripheral flow 42, and an inner core flow 44 surrounded by the outer peripheral flow 42. The shear layer between flows 42 and 44 is generally shown at 46.

[0065] Each of flows 42 and 44 is preferably a swirling flow, but may optionally and preferably also comprises an axial flow as shown in FIG. IB.

[0066] In some embodiments of the present invention, the chamber 12 has a length-to-diameter ratio that may range from approximately 2:1 to 50:1, such as 4:1, 8:1, 12:1, or 20:1, and with an internal diameter that may be selected anywhere from a few millimeters to several tens of centimeters for pilot and industrial installations. In some embodiments, the reaction chamber 12 is cylindrical and the flows 42, 44 swirl about a central axis 26 of the cylinder. The chamber 12 may be straight, slightly converging, slightly diverging, or segmented into sections of differing diameters to shape the axial pressure gradients.

[0067] A representative example of a reaction chamber suitable for forming oppositely directed flows is provided in the Examples section that follows.

[0068] In some embodiments of the present invention, system 10 comprises a swirling apparatus 18 at the end of the reaction chamber 12 where the slurry is received. For example, the inlet 14 can be formed in the swirling apparatus 18. Apparatus 18 imparts swirl to the stream 16 of the incoming slurry. Swirling apparatus 18 may employ one or more tangential ports, scrolls, vanes, or helical entry channels to generate a controlled angular momentum in the flow, with a swirl number that may be adjusted for examplebetween about 0.3 and about 3.5, such as 0.6-1.2 for stable dual-core vortices or 1.2-2.5 for vigorous cavitation onset. In some embodiments, apparatus 18 is modular to allow exchange of inserts or vanes of differing angles. Apparatus 18 can be designed to operate over Reynolds numbers ranging from laminar-transition regimes up to fully turbulent regimes for example from about Re 5×103to about 5×106.

[0069] A representative example of a swirling apparatus according to some embodiments of the present invention is provided hereinbelow.

[0070] In some embodiments, the flows 42 and 44 in chamber 12 swirl about a common axis while having opposite mean axial components that establish a shear layer between them. The shear layer 46 between flows 42 and 44 exhibits elevated velocity gradients, anisotropic turbulence dominant in the radial direction, and a distribution of cavitation microbubbles that intermittently coalesce into super-cavitating cavities. In some embodiments, the resulting flow field generates mechanical oscillations that persist over frequencies from hundreds of hertz to hundreds of kilohertz, therebyenhancing mechanochemical events such as mechano-thermolysis of water, radical formation, and redox transformations at particle surfaces.

[0071] Cavitation nuclei may expand in low-pressure zones and then collapse as they transit to higher-pressure zones, with collapse events producing transient hot spots and shock fronts that ionize and dissociate the water. Concurrently, the strong swirl establishes a pronounced radial pressure gradient with lower static pressure at the core and higher static pressure near the wall, so that swirl-driven segregation may occur: lower-density phases and fine gas nuclei may be biased toward the core, while denser, more inertial particulates may experience an outward slip toward the wall of chamber 12. The immediate products of the cavitation microevents may include H+ and OH-, hydrogen atoms and hydroxyl radicals, and, by radical recombination, dissolved and finely dispersed molecular hydrogen and oxygen, as well as hydrogen peroxide formed from hydroxyl-radical pairing.

[0072] The flow field typically begins to sort the newly formed species by the combined action of convection, mixing-limited partitioning, and the foregoing swirl-driven segregation. The inner flow 44 may draw in the fraction of products and intermediates that are formed or persist on the core side of the shear layer and are favored by the low-pressure core, including H+ and hydrogen-bearing fragments, together with nanoscopic hydrogen nuclei that may be centrifuged toward the axis, so that the water carried with the inner flow 44 downstream becomes hydrogen-enriched, containing dissolved H2and micro- to nano-bubbles of hydrogen that may subsequently disengage. The peripheral flow 46 may receive the complementary fraction formed or stabilized on the peripheral side of the shear layer and favored by the near-wall region, including OH-, oxygen, and peroxide species, together with oxygen nuclei that may be swept outward by centrifugal effects, so that the water carried with the peripheral flow 42 becomes oxy gen-enriched and may contain dissolved O2, oxygen microbubbles, and measurable H2O2 transported away from the reaction zone.

[0073] Suspended redox-active particulates moving through the shear layer experience repeated microjet impingement and shock loading, which renew surfaces and accelerate heterogeneous reactions with water and steam present in and around collapsing cavitation bubbles. These interactions convert lower-valent solids to higher-valent solids while evolving molecular hydrogen, so that oxidized-form particulates are formed in situ within oxygenated microenvironments. In parallel, the same swirl-driven segregation biases denser and / or larger particulates toward the periphery, so that the oxidized-form particulates may remain finely suspended yet are swept preferentially along the peripheral side of the shear layer by the local pressure, velocity, and centrifugal fields. The oxygen-enriched water in the outer peripheral flow may convey thesesuspended oxidized-form particulates together with dissolved and finely dispersed oxygen and, where formed, hydrogen peroxide.

[0074] Representative examples of oxidized-form particulates suitable for the present embodiments include, without limitation, iron-based oxidized species such as iron(III) oxide Fe2O3(including hematite and maghemite), mixed-valent magnetite Fe3O4regarded as oxidized relative to FeO, ferric oxyhydroxides FeOOH in polymorphs including a-FeOOH (goethite), y-FeOOH (lepidocrocite), P-FeOOH (akaganeite), and 5-FeOOH (feroxyhyte), amorphous or poorly crystalline ferrihydrite, and ferric hydroxide Fe(OH)3; manganese-based oxidized species such as manganese dioxide MnO2, manganese(III) oxide MmCh, and manganese oxyhydroxides MnO(OH) (manganite, groutite) and hydrated Mn(IIVIV) oxides; cobalt-based oxidized species such as cobalt(II, III) oxide CO3O4, cobalt oxyhydroxide CoO(OH) / CoOOH, and hydrated cobalt(III) hydroxide phases; nickel -based oxidized species such as nickel oxyhydroxides NiO(OH) in P- and y-forms, higher nickel oxides including N12O3 and NiCb obtainable transiently or as hydrated derivatives, and hydrated nickel(III) phases; copper-based oxidized species such as cupric oxide CuO and cupric hydroxide Cu(OH)2; vanadium-based oxidized species such as vanadium pentoxide V2O5 and hydrated vanadium pentoxide gels V2O5 XH2O; molybdenum-based oxidized species such as molybdenum tri oxide MoO3 and hydrated molybdic oxide phases represented as MOO3 XH2O or H2MOO4 XH2O; tungsten-based oxidized species such as tungsten trioxide WO3 and hydrated tungstic oxides WO3 XH2O or H2WO4 XH2O; and cerium-based oxidized species such as cerium dioxide CeCh, hydrated ceria CeCh xHzO, and ceric hydroxide Ce(OH)4, together with mixtures, solid solutions, and core-shell particulates enriched in the higher-valent state of the corresponding element.

[0075] In some embodiments, the suspended oxidized-form particulates comprise iron(III) oxide (Fe2O3) and / or iron oxide (Fe3O4) formed in the process, optionally and preferably as a mixture whose ratio depends on local cavitation intensity and oxygen availability, and the mixture may further include hydrated forms or transient rust-like polyhydrates. In some embodiments, the peripheral flow 42 may further comprise hydrogen peroxide formed via recombination of hydroxyl radicals and via reactions in and around collapsing cavitation bubbles, and the peroxide content may be variable, for example from tens of milligrams per liter to several grams per liter depending on hydrodynamic and electrical conditions.

[0076] Not all particulates traversing the shear layer undergo oxidation under the transient local conditions established by cavitation. A fraction of the suspended solids may persist as, or be converted to, reduced-form particulates, including reduced hydrates and mixed-valent phases that are reduced relative to the oxidized-form particulates carried by the peripheral flow 42. Superimposed onhydrodynamic entrainment and axial suction associated with the core side of the shear layer, swirl-driven segregation of lighter, finer, or less aggregated fractions toward the low-pressure core may draw these reduced-form particulates from the shear layer into the inner flow 44, so that the hydrogen-enriched water in the inner flow 44 is populated with suspended reduced-form particulates derived from the redox active powder.

[0077] Representative examples of reduced-form particulates suitable for the present embodiments include, without limitation, iron-based reduced species such as wüstite FeO, ferrous hydroxide Fe(OH)2, mixed-valent magnetite Fe3O4as reduced relative to Fe2O3, oxygen-deficient iron oxides FeOx with x<1.5, and zero-valent iron Feo including Fe / FeOx core-shells; manganese-based reduced species such as MnO, Mn(0H)2, hausmannite Mn3O4as reduced relative to MnO2, sub-stoichiometric manganese oxides MnOx with l<x<2, and metallic Mno; cobalt-based reduced species such as CoO, CO(OH)2, sub-stoichiometric cobalt oxides CoOx with x about 1, and metallic Coo; nickel-based reduced species such as NiO, Ni(OH)2, sub-stoichiometric nickel oxides NiOx with x about 1, and metallic Nio; copper-based reduced species such as cuprous oxide Cu2O and metallic Cuo; vanadium-based reduced oxides such as V2O3, VO2, Magneli-type suboxides VnO2n-1including V4O7and V5O9, and metallic Vo; molybdenum-based reduced oxides such as MoO2 and sub-stoichiometric MoO3-xincluding Mo4O11and Mo8O23, and metallic Moo; tungsten-based reduced oxides such as WO2 and sub-stoichiometric WO3-X including W18O49 and W5O14, and metallic Wo; and cerium-based reduced species such as Ce2O3, non-stoichiometric ceria CeO2-x enriched in Ce(III), and cerous hydroxide Ce(OH)3; optionally and preferably including transient hydride- or protonated- surface variants of any of the foregoing that, under process pH and ionic strength, present neutral or positive zeta potential and thereby migrate toward the negatively biased first outlet.

[0078] The outer peripheral flow 42 proceeds toward a peripheral outlet 20 located downstream of the peripheral flow 42, and the inner core flow 44 proceeds in the opposite axial direction toward a central outlet 24, located downstream of the inner core flow 44 at the opposite end of chamber 12.

[0079] When apparatus 18 is employed, axial pressure gradients are preferably directed toward and away from apparatus 18 in the peripheral flow 42 and inner flow 44, respectively. In these embodiments, apparatus 18 can be positioned between outlet 24 and chamber 12, in which case the inner core flow 44 proceeds from chamber 12 toward apparatus 18, through a central bore 28 of apparatus 18, and into outlet 24 on the other side of apparatus 18.

[0080] Outlet 24 discharges a first liquid stream 30, which comprises the hydrogen-enriched water and the suspended reduced-form particulates derived from the redox-active powder that are entrained from the shear layer into the inner flow 44. Outlet 24 may comprise a tube aligned with the centralaxis 26 of reaction chamber 12 so that it samples the inner vortex core. In some embodiments of the present invention, the tube of outlet 24 is interchangeable to tune hydraulic resistance and residence time. The tube of outlet 24 may be fabricated from an electrically conductive material, such as, but not limited to, stainless steel, nickel alloys, titanium, tantalum, conductive carbon composites, copper alloys, or combinations thereof. The tube of outlet 24 may optionally and preferably comprise dielectric segments upstream or downstream for electrical isolation.

[0081] Outlet 20 is optionally and preferably arranged adjacent to an inner surface of wall 22 of chamber 12. Outlet 20 receives the peripheral flow 42 and discharges a second liquid stream 32, which comprises the oxygen-enriched water and the suspended oxidized-form particulates derived from the redox-active powder in the shear layer. Outlet 20 optionally and preferably comprises an annular port or a multiple-port peripheral manifold that extracts flow 44 closer to wall 22 than outlet 24, and may comprise separate outlets for venting a gaseous fraction and for conducting a mixture comprising the oxidized-form particulates and water.

[0082] In some embodiments of the present invention, system 10 comprises a power source configured to apply a negative bias to outlet 24 relative to wall 22 of reaction chamber 12, so that the tube of outlet 24 acts as a cathode and an electrically conductive inner surface of wall 22 acts as an anode. In these embodiments, the inner wall 22 of chamber 12 can comprise stainless steel, nickel alloy, titanium with a conductive inner liner, graphite-lined steel, or a conductive coating such as doped diamond-like carbon, conductive ceramics, or metallized polymer. In some embodiments, power source 34 is a direct-current source with a voltage output that may be adjustable, for example, from about 1 V to about 1000 V or more for many aqueous slurries, and with current limiting from milliamperes to tens of amperes depending on electrode area and conductivity. In some embodiments, the power source is configured to operate in a pulsed mode to modulate the potential of outlet 24 relative to wall 22 of reaction chamber 12. The pulsing may take the form of square, rectangular, trapezoidal, sinusoidal, sawtooth, or arbitrary waveforms with duty cycles from about 5% to about 95%. The repetition frequencies are optionally and preferably coordinated with hydrodynamic and acoustic time scales of the cavitation, and can be from about 0.1 Hz to about 1 MHz.

[0083] The electrical action facilitates separation of dissociated species in the flows 42, 44.

[0084] Specifically, the cathodic bias may draw cations, including H+, and electron-accepting reduced species toward the inner core, while the anodic wall may attract anions such as OH- and stabilize oxidizing intermediates. The same bias may locally support hydrogen evolution at outlet 24 (2H2O + 2e“ — > H2 + 2OH“ or 2H++ 2e“ —> H2, depending on micro-pH) and oxygen evolution at the wall 22 (4OH“ —> 02 + 2H2O + 4e“ or 2H2O —> 02 + 4H++ 4e“), so that dissolved H2 and O2, together withfine bubbles of each, naturally enrich different sides of the flow. Within this environment, the redox-active powder participates heterogeneously. For example, when the redox active powder comprises FeO, steam and water impinging on freshly renewed Fe(II) surfaces in and near the collapsing bubbles may oxidize FeO to Fe3O4 or Fe2O3 while releasing H2, for example along routes analogous to 3FeO + H2O → Fe3O4+ H2or 2FeO + H2O → Fe2O3+ H2. Transient disproportionation of defect-rich FeO may form metallic Fe that immediately reacts with water or steam to give FeO and H2, providing an alternative microscopic path to the same hydrogen outcome under cavitation. In parallel, radical chemistry at solid-liquid interfaces may favor binding of •OH at Fe(II) sites to yield OH−, slowing wasteful H• + •OH recombination and tilting the local balance toward H2 formation. As these reactions proceed, the solids emerging from the shear layer may diverge: reduced-form particulates enriched in Fe(II) states may retain surface charges and hydrodynamic affinities that keep them in the inner stream under cathodic attraction, while oxidized-form particulates such as Fe3O4and Fe2O3may be nudged outward by anodic attraction, by their surface chemistry in the prevailing pH.

[0085] In some embodiments, system 10 comprises a magnetic field generator 36 arranged to apply a magnetic field to the flows within chamber 12. The magnetic field is optionally and preferably axial relative to the central axis 26 of the reaction chamber. In some embodiments, the magnetic field generator may be realized using permanent magnets, such as rare-earth neodymium-iron-boron or samarium-cobalt rings, arc segments, or Halbach arrays positioned around the chamber, or by electromagnetic coils with ferromagnetic yokes and pole pieces, or by hybrid permanent-electromagnet structures for tunability. In some embodiments, the magnetic field generator 36 may be configured to produce a magnetic field having a radial gradient across the shear layer, for example by shaping pole pieces or arranging magnetization so that flux density is greater near the wall and decreases toward the axis or vice versa, thereby interacting with paramagnetic species, magnetizable particulates such as Fe3O4, and charged microbubbles to influence transport across the shear layer. In some embodiments, magnetic flux densities may range from millitesla to several hundred millitesla or more, such as 5 mT, 20 mT, 100 mT, 300 mT, and gradients may be established over millimeter to centimeter scales.

[0086] Reference is now made to FIG. 2, which is a schematic illustration showing system 10 in greater detail, according to some embodiments of the present invention. In the illustrated embodiment, system 10 comprises a hydrogen gas holder 52 in fluid communication with outlet 24 and an oxygen gas holder 54 in fluid communication with outlet 20, each configured to accumulate the respective gas separated from its corresponding liquid stream. In some embodiments, gas holders52 and 54 may take the form of fixed-roof vessels with disengagement space, water-sealed bell gasholders, membrane or bladder tanks, flexible film domes, or piston-type accumulators, and may include internal demisters, coalescers, or vane packs to limit entrainment of droplets. The gases in gas holders 52 and 54 typically accumulate in the upper parts of the holders, with liquid and solid species from the respective streams 30 and 32 occupying the lower parts thereof. In the illustrated embodiments, outlet 20 comprises separate outlets for venting a gaseous fraction into the upper part of gas holder 54, and a mixture comprising oxidized-form particulates and water into the lower part of gas holder 54.

[0087] In some embodiments, a hydrogen compressor 56 may be connected to the hydrogen gas holder 52, and a hydrogen receiver 58 may be connected to the outlet of the hydrogen compressor 56. The compressor 56 may be, for example, of the oil-free diaphragm, scroll, piston, ionic-liquid, or electrochemical type, with multi-stage intercooling to achieve delivery pressures, for example, from 10 bar to 700 bar or higher, and the receiver 58 may be a pressure vessel constructed from steel, aluminum-lined composite, or polymer-lined composite.

[0088] In some embodiments, an oxygen compressor 60 may be connected to the oxygen gas holder 54 and an oxygen receiver 62 may be connected to the outlet of the oxygen compressor 60. Compressor 60 and receiver 62 can be of any type described above with respect to compressor 56 and receiver 58, respectively. In some embodiments, a portion of water accumulating in the oxygen-side gas holder may be directed to the hydrogen-side gas holder to manage water balance, temperature, or gas scrubbing, and may be metered by valves or pumps to control liquid levels.

[0089] In some embodiments, system 10 may further comprise a separator 64 configured to separate water from oxidized-form particulates in the holder 54. In some embodiments, the separator may be a hydrocyclone, centrifugal separator, lamella clarifier, filter press, membrane filter, decanter centrifuge, disk-stack centrifuge, settling tank, or combinations thereof to achieve solids concentrations suitable for downstream regeneration. In some embodiments of the present invention system 10 comprises a water pump 76 configured to return at least a portion of the separated water to the reaction chamber 12 via inlet 14. The pump 76 may be a centrifugal, progressive cavity, peristaltic, diaphragm, or gear pump selected for the slurry’s rheology. In some embodiments, the separated water may be recycled directly to the inlet 14. In some embodiments, the separated water is passed through a discharge chamber 68, which can serve as a buffer module ahead of chamber 12, and may, for example, decouple pump pulsations, trap stray bubbles, and stabilize inlet conditions. The separated oxidized-form particulates are delivered from separator 64 into a storage tank 78.System 10 may further comprise a recycling pump 66 configured to recycle a slurry containing the water and reduced particulars that are received by holder 52 from stream 30, back into chamber 12. Recycling pump 66 may feed the recycled slurry directly to inlet 14 or via discharge chamber 68.

[0090] In embodiments in which both pumps 66 and 76 are employed, the separated water delivered by pump 76 can be combined with the slurry delivered by pump 66, as illustrated in FIG. 2.

[0091] In some embodiments of the present invention, system 10 comprises a mixer-dosing device 70 configured to form the slurry from water supplied from a source water tank 72 and redox active powder supplied from a powder tank 74, which in some embodiments of the present invention is provided as a sealed hopper. In some embodiments, the water may be deionized, distilled, softened, potable, industrial, brackish, or seawater, and may optionally and preferably be pre-conditioned to a target pH or conductivity using buffering salts, acids, or bases such as sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, sodium carbonate, sodium bicarbonate, potassium hydroxide, sodium hydroxide, dilute sulfuric acid, or dilute nitric acid. In some embodiments, the sealed hopper 74 may include inert gas blanketing with nitrogen or argon, vibration or agitation to prevent bridging, and metering feeders such as screw feeders, rotary valves, loss-in-weight feeders, or venturi eductors to dose solids into a wetting and dispersing section. In some embodiments, slurry solids content may range for example from about 0.1 wt% to about 60 wt% depending on particle size and viscosity, such as 0.5-10 wt% for fine powders and 5-40 wt% for coarser powders. In some embodiments, the mixer-dosing device may incorporate high-shear stator-rotor heads, ultrasonic transducers, inline static mixers, or jet eductors to deagglomerate particles and to produce a uniform suspension, and may include temperature conditioning.

[0092] Mixer-dosing device 70 can output the slurry directly into inlet 14 or into discharge chamber 68. In some embodiments of the present invention mixer-dosing device 70 outputs the slurry into holder 52 where it is mixed also with the water and reduced particulars received from stream 30.

[0093] In some embodiments, system 10 comprises an additional generator 80 configured to apply to the slurry at least one action selected from electrical discharge, acoustic action, electromagnetic action, thermal action, and chemical action. In some embodiments, the additional generator 80 may comprise an acoustic transducer coupled to a wall of the reaction chamber or to an upstream conduit to inject ultrasound or lower-frequency vibrations; an electromagnetic coil arranged around the reaction chamber or an upstream section to impose time-varying fields such as RF, LF, or microwave energy; and an electrical discharge source such as a pulsed electric field cell, a corona discharge, a dielectric barrier discharge, a spark discharge, or a plasma microreactor that acts on the slurry upstream of the reaction chamber to seed radicals, modify surface states of particulates, adjust zetapotential, or pre-nucleate cavitation sites. In some embodiments, thermal action may be applied by inline heaters or heat exchangers to set temperature ranges from about 10°C to about 95°C or higher according to process optimization, and chemical action may include dosing of promoters, inhibitors, complexing agents, or scavengers to steer radical pathways. The hydrodynamic, electric, magnetic, acoustic, thermal, and chemical influences may be coordinated so that within the reaction chamber 12 the cavitation field, the electrohydrodynamic migration of ions, and the magneto-hydrodynamic forces act synergistically.

[0094] In some embodiments, a method of generating hydrogen may comprise forming within a reaction chamber having first and second outlets, oppositely directed swirling flows of a slurry containing water and a redox active powder, with a shear layer between the flows; applying a negative bias to the first outlet relative to the reaction chamber; discharging through the first outlet, downstream of the inner flow, a first liquid stream comprising hydrogen enriched water and suspended reduced-form particulates derived from the redox active powder in the shear layer; and discharging, through the second outlet downstream of the peripheral flow, a second liquid stream comprising oxygen enriched water and suspended oxidized-form particulates derived from the redox-active powder in the shear layer. In some embodiments, forming the flows may be carried out by introducing the slurry through a swirling apparatus device at the inlet of the reaction chamber so that the swirl number and axial pressure gradients produce sustained cavitation. In some embodiments, a negative bias of the first outlet is applied by applying a direct current electric potential between the first outlet and the electrically conductive inner surface of the reaction chamber and connecting the inner surface of the reaction chamber as an anode. In some embodiments, applying a magnetic field to the flows using a magnetic field generator may include producing an axial magnetic field relative to the central axis and shaping a radial gradient across the shear layer.

[0095] In some embodiments of the present invention, the method may further comprise forming the slurry by mixing water from a source water tank with the redox active powder supplied from a sealed hopper in a mixer-dosing device, collecting hydrogen separated from the first liquid stream in a hydrogen gas holder, compressing the collected hydrogen with a hydrogen compressor, and storing the compressed hydrogen in a hydrogen receiver. In some embodiments, the method may further comprise collecting oxygen separated from the second liquid stream in an oxygen gas holder, compressing the collected oxygen with an oxygen compressor, and storing the compressed oxygen in an oxygen receiver. In some embodiments, the method may further comprise separating water from oxidized-form particulates in the second liquid stream using a separator, returning at least a portion of the separated water to the reaction chamber, recirculating at least a portion of the slurry back tothe reaction chamber to increase utilization, and directing oxidized-form particulates from the second liquid stream to a regeneration process to re-form the redox active powder.

[0096] In some embodiments, water chemistry may be tuned so that pH, ionic strength, and dissolved gas content are adapted to achieve desired yields. For example, operation may occur under initially aerated, de-aerated, nitrogen-blanketed, or oxy gen-enriched conditions, and the feed water may include traces of salts to adjust conductivity for electrical control without causing excessive corrosion. In some embodiments, the operating temperature of the slurry may be allowed to rise into ranges such as 40-90°C during recirculation due to hydrodynamic work and exothermic reactions, while heat exchangers may maintain targeted setpoints for stability, and back-pressure regulation may set absolute pressures from near atmospheric to several bar to influence cavitation regimes.

[0097] In some embodiments of the present invention, materials of system 10 for wetted parts may include, without limitation, stainless steels, nickel-based alloys, titanium, ceramics such as alumina or zirconia, polymeric liners such as PTFE, PF A, PVDF, or PEEK, elastomers compatible with oxidants such as EPDM and FKM, and conductive coatings for electrode surfaces designed to resist erosion in cavitating flows. In some embodiments, the tube of outlet 24 may include replaceable tips or sleeves to adapt to wear, and the chamber wall 22 may be electrically sectioned or segmented to shape current distribution along the chamber.

[0098] The system and method of the present embodiments thus provide a controllable hydrodynamic-electro-magneto-acoustic environment in which a slurry of water and redox-active powder is split into counter-flowing, co-swirling streams that selectively discharge a hydrogen-enriched inner stream carrying reduced particulates through a negatively biased central outlet and an oxy gen-enriched peripheral stream carrying oxidized particulates and hydrogen peroxide through a peripheral outlet, while ancillary subsystems collect, compress, store, separate, recirculate, and regenerate to complete a closed-loop hydrogen production cycle.

[0099] As used herein the term “about” refers to ± 10 %

[0100] The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

[0101] The term “consisting of’ means “including and limited to”.

[0102] The term "consisting essentially of' means that the composition, method or structure may include additional ingredients, steps and / or parts, but only if the additional ingredients, steps and / or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

[0103] Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0104] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging / ranges between” a first indicate number and a second indicate number and “ranging / ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

[0105] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0106] Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.

[0107] EXAMPLES

[0108] Reference is now made to the following examples, which together with the above descriptions illustrate some embodiments of the invention in a non limiting fashion.Example 1

[0109] Exemplified Reaction Chamber

[0110] FIGs. 3 A-E illustrate an example reaction chamber which can be used as reaction chamber 12 according to some embodiments of the present invention.

[0111] With reference to FIG. 1A, reaction chamber 12 can comprise an inlet 126, swirling apparatus 18, a tapered hollow structure 142, a first outlet 144, and a second outlet 116. First outlet 144 may enact outlet 24 and second outlet 116 may enact outlet 20 shown in FIGs. 1 A, IB and 2.

[0112] Inlet 126 is connected to a source providing the slurry (not shown, see, e.g., mixer-dosing device 70 in FIG. 2), and swirling apparatus 18 is arranged to receive the slurry. For clarity of presentation, chamber 12 is shown to comprise a first hull 101 and a second hull 102, wherein swirling apparatus 18 is in first hull 101 and tapered hollow structure 142 is in second hull 102. Magnified partial views of chamber 12, showing first 101 and second 102 hulls are shown in FIGs. 3B and 3C, respectively.

[0113] Apparatus 18 is configured to accelerate the slurry to form a helical flow of the slurry, and to induce fluid turbulence and cavitation. The helical flow is typically along more than one helix and is therefore manifested as a three-dimensional vortex having a dominant circumferential velocity component, and also an axial velocity component along a longitudinal axis 148 of chamber 12, which axial velocity component is directed predominantly toward the second outlet 216. In some embodiments described below, there is an additional return flow that intensifies the turbulence and cavitation. The additional return flow can also be helical, contributing to a counter vortex having a dominant circumferential velocity component and also an axial velocity component which is predominantly away from the second outlet 216, wherein the vortex and counter vortex are generally concentric with respect to each other.

[0114] FIG. 3D is a transverse cross-sectional view along the line A — A of FIG. 3A, showing swirling apparatus 18 in greater detail. Swirling apparatus 18 is typically enclosed in a hull 140, for example, by means of screws 125 or other fixating members, and comprises a streamlined spiral surface 160 that guides and accelerates the fluid entering through the inlet 126. The spiral surface can form any type of spiral. Representative examples of spiral types suitable for the present embodiments, include, without limitation, an Archimedean spiral, a Fermat's spiral, a logarithmic spiral, a lituus spiral, and a hyperbolic spiral. In some embodiments of the present invention the spiral is an Archimedean spiral. Preferably, the acceleration is in a plane that is perpendicular to longitudinal axis 148. The fluid is accelerated preferably to increase the tangential component of thefluid velocity, with a decrease in the radial component of the velocity due to the streamlined surface of the spiral.

[0115] Chamber 12 optionally and preferably comprises a conical element 104 having an axial inlet opening 105 and an axial outlet opening 103, and being positioned between apparatus 18 and outlet 144. Openings 105 and 103 may enact bore 28 shown in FIG. 1 A. Apparatus 18 and conical element 104 can be connected to each other by means a flange connector 133, preferably arranged to ensure aligned and sealed connection.

[0116] Hollow structure 142 has a proximal end 150 and a distal end 152, and is configured for receiving the helical flow at its proximal end 150 and separating it into the inner flow within hollow structure 142 and the peripheral flow outside hollow structure 142 (see FIG. IB for schematic illustrations of the inner 44 and peripheral 42 flows). In some embodiments of the present invention hollow structure 142 is stepwise tapered, wherein its diameter reduces toward its distal end 152 in a series of distinct, discrete steps. Alternatively, hollow structure 142 can be tapered continuously. The inner and peripheral flows are discharged by the outlets 144 and 116, where first outlet 144 discharges the inner flow, and second outlet 116 discharges the peripheral flow. In some embodiments of the present invention first 144 and second 116 outlets are at opposite sides of swirling apparatus 18. For example, as illustrated in FIGs. 3A and 3C, second outlet 116 can be near distal end 152 of structure 142, e.g., circumferential and co-planar with distal end 152, and outlet 144 can be provided in the form of pipe 106 mounted at a side of apparatus 18 that is opposite to tapered hollow structure 142. Pipe 106 can be connected to an external line (not shown) via a flange connector 134.

[0117] Chamber 12 optionally and preferably comprises a tubular structure 146 that encapsulates hollow structure 142, wherein swirling apparatus 18 is arranged to feed the outer flow 42 into tubular structure 146. Tubular structure 146 is oriented such that it share the longitudinal axis with chamber 12. Preferably, inlet 126 is arranged to guide the slurry to apparatus 18 along a direction that generally perpendicular to the longitudinal axis 148. The dimensions and shape of tubular structure 146 are optionally and preferably selected such that at least one of flows 42, 44 produced by apparatus 18 generates acoustic resonance in tubular structure 146. The Inventor found that such acoustic resonance intensifies a formation of anisotropic turbulence and pressure fluctuations, and enhances cavitation. Specifically, the acoustic resonance causes local decrease in the pressure of the liquid phase of the slurry to a level below its vapor pressure, leading to a cavitation in the form of vapor or gas-filled cavities within the liquid phase of the slurry. When the flow moves the cavities to regions of higher pressure within the liquid phase, they collapse rapidly. The collapse of these cavitiesgenerate forces and shock waves that are sufficiently high to break the molecular bonds and dissociate the molecules of the liquid phase and / or redox active powder. Thus, the water molecule H2O can dissociate into a hydrogen ion and a hydroxide ion. The presence of these ions in the water may result in formations of hydrogen molecules and hydrogen peroxide molecules.

[0118] Preferably, but not necessarily, tubular structure 146 has a shape of a right cylinder. Other shapes, preferably shapes having round walls, are also contemplated. Tubular structure 146 is optionally and preferably manufactured from a transparent material. An advantage of this embodiment is that it allows visual inspection of the flows in structure 146, for example, to determine whether or not an acoustic resonance is generated.

[0119] With reference to FIGs. 3B and 3C, tubular structure 146 optionally and preferably have a first segment 146a which is between apparatus 18 and tapered hollow structure 142, and a second segment 146b which encompasses tapered hollow structure 142. The length of segment 146a is denoted LI, the length of segment 146b is denoted L2, and the length of tubular structure 146 is denoted L, where L, LI, and L2 satisfy L=L1+L2. The length of tapered hollow structure 142 is typically the same or approximately the same (e.g., within a 10% tolerance) as the length of second segment 146b. Tubular structure 146 can be provided as a monolithic structure including both segments 146a and 146b as two segments of the same monolithic structure. Alternatively, segments 146a and 146b can be assembled to form tubular structure 146 has a shape. In the schematic illustration of FIG. 3C, which is not to be considered as limiting, segments 146a and 146b are connected to each other by a flange connector 132.

[0120] In some embodiments of the present invention LI is larger than L2. A typical value for the ratio L1 / L2 is from about 1.5 to about 5. The ratio L1 / L2 is preferably selected based on the expected volumetric flow rate provided by the fluid source connected to inlet 126. As a representative example, in experiments performed by the Inventor for a volumetric flow rate of about 6.67×10-4m3 / s (about 2.4 m3 / hour) tubular structure 146 had a shape of a right cylinder, segment 146a had a length LI of about 0.25 meters (250 mm) and segment 146a had a length L2 of about 0.105 meters (105 mm), providing a ratio L1 / L2 of about 2.38.

[0121] In some embodiments of the present invention hollow structure 142 is at least partially closed at its distal end 152, forcing a return flow toward swirling apparatus 18 and opposite to the peripheral flow. The return flow optionally and preferably passes through apparatus 18 and exits chamber 12 via first outlet 144, allowing first outlet 144 to be at an opposite side of swirling apparatus 18 relative to second outlet 116.Preferably, chamber 12 comprises a controllable valve 109 mounted at distal end 152 in a manner that allows controlling the extend at which distal end 152 is closed. For example, when valve 109 assumes a closed state, distal end 152 is completely closed so that the slurry is prevented from exiting tapered hollow structure 142 through distal end 152. When valve 109 assumes a state other than a closed state (opened or partially opened state), a portion of the inner flow exits through distal end 152. In some embodiments, system 10 comprises a controller 154 having a circuit 156 configured for controlling valve 109 so as to select the flow rate of the slurry that is allowed to exit tapered hollow structure 142 through distal end 152. Preferably, circuit 156 automatically controls valve 109 based on a ratio between the rate of the inner flow and the rate of the peripheral flow. Alternatively or additionally, valve 109 can be controlled by a user, e.g., via a user interface 158 that may, for example, be provided with controller 154.

[0122] In embodiments in which valve 109 is employed, the return flow is generated at distal end 152. The return flow optionally and preferably passes through apparatus 18, introduced into conical element 104 via inlet 105, and is thereafter discharged via outlet 144. When valve 109 is not completely closed, part of the inner flow is controllably discharged though the distal end 152 of tapered hollow structure 142.

[0123] User interface 158 may include buttons, which are activated by pressing, and may take different shapes depending on each button's particular function. User interface 158 may also include LEDs to indicate the state of vain various exemplary embodiments of the invention 109 or other elements of system 10. User interface 158 may optionally and preferably comprise a touch screen or a keyboard. User interface 158 can be mounted on controller 154, as illustrated in FIGs. 3A and 3C, or be remote to controller 154 in which case communication between interface 158 and controller 154 is established via a communication network.

[0124] With specific reference to hull 102, in some embodiments of the present invention tapered hollow structure 142 comprises a set of hollow casings. In the representative example of FIGs. 3 A and 3C, which is not to be considered as limiting, structure 142 comprises four hollow casings 111, 112, 113, and 114, but it is to be understood that structure 142 can comprise any number of hollow casings. The hollow casings of structure 142 are arranged with open channels 118, 119, 120 between adjacent casings, and optionally and preferably also an open channel 117 between the first casing 111 of the set and the inner surface of tubular structure 146 (see enlarged view in FIG. 3C). Specifically for the schematic and non-limiting illustration of FIG. 3C, channel 118 is formed between the inner surface of casing 111 and the outer surface of casing 112, channel 119 is formed between the outer surface of casing 113 and the inner surface of casing 112, and channel 120 is formed between theinner surface of casing 113 and the outer surface of casing 114. Another channel 121 is formed between the inner surface of tubular structure 146 and the outer surfaces of all casings 111-114. The last casing of the set (casing 114 in the present example) is optionally and preferably docked with a lid 115, wherein the outlet 116 is formed in lid 115.

[0125] The channels 117-120 establish fluid communications between the inner flow (within the casings of structure 142) and the peripheral flow (outside the casings of structure 142), and are configured to guide a portion of the inner flow (for example, the swirling component thereof, see FIG. 2) into channel 121 so as to combine it with the peripheral flow.

[0126] The hollow casings of structure 142 preferably form a telescopic set, with decreasing diameter away from first hull 101 and toward the distal end 152. In these embodiments, each of the casings, except the first 111, is partially introduced into the interior of the preceding, larger in diameter, casing, wherein the channels are formed in the overlap region between the outer wall of smaller-diameter casing and the inner wall of the larger-diameter casing. A transverse cross-sectional view of the telescopic hollow casings 111-114, along the line B — B of FIG. 1A, is illustrated in FIG. 3E. The hollow casings 111-114 are typically shaped as non-tapered cylinders, in which case structure 142 is stepwise tapered, but other shapes are also contemplated, preferably round wall shapes.

[0127] The alignment and fixation of the first casing 111 to the inner surface of second segment 146b can be carried out by means of one or more ribs 127, and the alignments and fixation of adjacent casings (111-114, in the present example) to each other can be carried out by means of one or more ribs 128, 129, and 130, respectively. The alignment and fixation of the entire set of casings that form tapered hollow structure 142 to the inner surface of to the inner surface of second segment 146b can be carried out by means of one or more ribs 131, as illustrated in the cross-sectional view of FIG. 3E.

[0128] FIG. 1 A also illustrates a container 107 which is in fluid communication with the outside of tapered hollow structure 142 via second outlet 116. Container 107 can receive the peripheral flow from the second outlet 116, and can therefore enact holder 54 of FIG. 2. In embodiments in which valve 109 is employed, and when valve 109 is not fully closed, a portion of the inner flow exits via valve 109 also into container 107. In some embodiments, valve 109 is sealed with a nut 122, screwed into a fitting attached to the bottom of container 107 having a threaded connection with stem of valve 109. Container 107 typically comprises a container outlet 108, which discharges fluid out of container 107, for example, into separator 64 (FIG. 2). Container outlet 108 can be connected to an external line (not shown) by means of a flange connector 135.Example 2

[0129] Exemplified Process

[0130] This Example describes an example process for hydrogen production using cavitation effects.

[0131] List of symbols and abbreviations

[0132] The following abbreviations and conventions are used herein:

[0133] FeO - iron oxide;

[0134] H2O – water;

[0135] H is a hydrogen ion;

[0136] Fe(OH)2– iron oxide hydrate;

[0137] Fe(OH)3– iron oxide hydrate;

[0138] Fe2O3– iron oxide (III);

[0139] O2– oxygen;

[0140] OH - hydroxyl group ion;

[0141] H2– Hydrogen;

[0142] pH is the level of acidity;

[0143] N2– nitrogen;

[0144] HNO2– nitrous acid;

[0145] HNO3– nitric acid;

[0146] CO2– carbon dioxide (carbon dioxide);

[0147] H2O2is hydrogen peroxide (peroxide).

[0148] Fe2+ and Fe3+ are iron ions;

[0149] ΔG is the change in free energy, J / mol;

[0150] ΔH is the change in entilpy, J / mol;

[0151] ΔS is the change in entropy, J / mol;

[0152] M is the molar mass g / mol;

[0153] v is the amount of substance, mole;

[0154] m is the weight, kg;

[0155] V - volume, m3;

[0156] p is density, kg / m3;

[0157] Q - capacity, m3 / hour;

[0158] H - head, m;

[0159] G - consumption, kg / s;

[0160] q is the specific consumption of electric energy, kWh / Nm3;C is the cost price, rubles / kg;

[0161] Z - costs, rubles;

[0162] W - speed, m / s;

[0163] P - pressure, Pa;

[0164] T (t) - temperature, K or °C;

[0165] SZA - nozzle twisting device;

[0166] F - area, m2;

[0167] D (d) - diameter, m;

[0168] L - length;

[0169] n is the quantity.

[0170] Introduction

[0171] In a method for processing oxygen-containing compounds of transition metals, iron oxide is ground into powder, and treated with a concentrated beam of accelerated electrons to form high-purity solid products, mainly iron oxide. Atomic oxygen and hydrogen from are then isolated.

[0172] Briefly, in this method, iron oxide FeO is treated in water H2O to obtain hydrogen H, iron oxide hydrate Fe(OH)2 and iron oxide hydrate Fe(OH)3. The iron oxide hydrate is converted into iron oxide hydrate. The suspension of iron oxide hydrate is sent to a sedimentation tank. Slip with a moisture content of up to 20% water is obtained in the sedimentation tank. The water is evaporated from the slip before the iron oxide hydrate turns into an anhydrous state - dry iron oxide powder (Fe2O3), which is returned to the electron beam.

[0173] In the present Example, hydrogen gas us produced in a chamber in the presence of a catalyst under the action of hydrodynamic cavitation.

[0174] Cavitation is the formation of discontinuities in the continuity of a liquid as a result of a local pressure drop. If the pressure decrease occurs due to high local velocities in the flow of a moving droplet, then cavitation is considered hydrodynamic, and if due to the passage of acoustic waves in the liquid, it is considered acoustic.

[0175] The effect of cavitation is accompanied by micro-explosions, ultrasound, as well as mechanical cuts and collisions under the influence of hundreds of cutting pairs moving towards each other at a high linear speed. The value of this speed is several tens of meters per second, which makes it possible to cut the dispersed substances into the smallest microparticles. Typically, these are micropulses, with hundreds of thousands of micro-impulses per minute.

[0176] Hydrodynamic cavitation occurs in areas of flow where the pressure drops to a critical value, below which the gas or vapor bubbles present in the liquid - the nuclei of cavitation - are allowed togrow indefinitely. Moving into a zone of high pressure, the bubble shrinks. If a bubble contains a sufficient amount of gas, it returns to its original radius and is thus able to undergo several cycles of damped oscillations.

[0177] If the bubble contains little amount of gas, it collapses completely in the first period. The contraction of the bubble occurs at high speed and is accompanied by a sound pulse, which is stronger the less gas there was in the bubble. At high cavitation intensity, many bubbles are formed and collapsed, which create a strong solid spectrum noise in the range from hundreds of hertz to hundreds of kilohertz. A body streamlined by liquid is surrounded by a well-defined cavitation zone filled with moving bubbles.

[0178] The cavitation mode can occur at pressures much lower than the pressure of saturated vapor. The calculated tensile strength of water, taking into account thermal fluctuations, is about 1500 kgf / cm2(150 MPa). Such tensile strength is rarely attainable. Practically, the maximum achieved tensile stress of thoroughly purified water is about 280 kgf / cm2(28 MPa), and for ordinary liquids, rupture occurs soon after the saturated vapor pressure is reached due to the presence of cavitation nuclei, including any kind of inhomogeneities on the surface of a solid body or in a liquid, e.g., poorly wetted areas, solid particles, microscopic gas bubbles in surfactant shells, which do not allow them to dissolve, etc.

[0179] With the strengthening of hydrodynamic cavitation, the bubbles combine into a common cavity and the flow around becomes jetty. This phenomenon is called super-cavitation.

[0180] The use of hydrodynamic and electro-magneto-hydrodynamic action on the generated cavitation in twisted countercurrent flows in a field with a high radial static pressure gradient, highly developed anisotropic turbulence and intense acoustic oscillations leads to mechano-thermolysis of the water structure with the appearance of free hydrogen bonds.

[0181] Rapid saturation of water with oxygen O2 is observed, explained by the presence of diffusion (due to the high compression ratio of the vapor-gas content of the cavitation micro bubble), as well as kinetic mechanisms.

[0182] The increase in the concentration of oxygen O2 is due to the hydrodynamic cavitation thermolysis of water into hydrogen ions H and the hydroxyl group OH of the corresponding mechanochemical reactions.

[0183] As a result of cavitation treatment, the synthesis of various chemical compounds occurs, the output of which depends on the treatment mode, the presence of impurities in the water and gas content. Thermolysis of water leads to the synthesis of hydrogen molecules H2 and oxygen O2, whichcontributes to a decrease in the pH level. Treatment in the N2 nitrogen medium increases the acidity of the system due to the formation of nitrogenous HNO2and nitric HNO3acids.

[0184] Under the influence of cavitation in an aqueous solution containing active gases, a variety of chemical reactions can be carried out. Cavitation initiation is reduced to ionization and excitation of water molecules, noble and active gases, as well as to the dissociation of hydrogen molecules H2. Each of these processes takes about 10-14s. Due to the fact that the duration of the bubble collapse stage (about 10-9- 10-6) s, the processes of energy transfer and recharging become possible with the participation of molecules of inert gases going in the gas phase.

[0185] In the cavitation cavity, radical transformation reactions take place with the participation of chemically active gases and radical recombination in a timescale of approximately 10-7- 10-6s. As a result of these processes, after the collapse of the cavitation bubble, the decomposition products of water molecules H2O pass into the solution, leading to the accumulation of molecular oxygen O2, hydrogen H2 and other compounds in the water.

[0186] This Example demonstrates a cost-effective process for obtaining hydrogen from water. Described are optimal mass ratio of the components of iron oxide FeO and water H2O in the mixture, effective influence on the structure of flows in a mixture of iron oxide FeO and water H2O to obtain the maximum rate of chemical processes in a device that implements the goal, experimental facility that can implements the generation of hydrogen from water, and a closed cycle for the production of hydrogen from water by regeneration of iron oxide FeO from iron oxide (III) Fe2O3, with the production of hydrogen H2.

[0187] Pilot Plant

[0188] With reference to FIG. 1 A, above, the reaction chamber, with the swirling apparatus installed at the inlet, forms two countercurrent twisted flows in the normal central axis of the chamber of the plane, at the point of its interface with the swirling apparatus. The peripheral flow moves from the swirling apparatus in the direction of the outlet 20, and the inner flow moves in the direction of the outlet 24.

[0189] In the plane of the swirling apparatus, a high radial static pressure gradient directed from the central axis of the chamber to its walls and two axial static pressure gradients are formed. One, in the peripheral flow, is directed towards the swirling apparatus, and the other, in the inner flow, is directed away from the swirling apparatus.

[0190] At the boundary of the separation of external and internal flows, due to the presence of axial shear velocities directed in opposite directions, intense anisotropic turbulence is formed, prevailing in the radial direction, generating high-frequency acoustic and mechanical oscillations.The structure of the flows formed in the chamber generates intense cavitation. When the cavitation bubbles collapse in their center, a sufficiently high temperature is reached, up to 10,0000 °C and a pressure of up to 100 MPa. As a result of this process, water molecules disintegrate into a positively charged hydrogen ion H+ and a negative ion OH-, and the negative OH ion moves into the external stream.

[0191] With the inner flow, the mixture of water H2O and the hydrogen ion H+ move in the direction of outlet 24, through which they go out for further processing. The water mixture H2O, the OH“ ion, oxygen residues O2, and the peroxide molecules H2O2 formed from OH ions, move in the direction of the outlet 20, through which they go out for further processing.

[0192] Thus, the structure of flows formed and moving ions formed in the chamber intensify the processes of water separation. The ratio of iron oxide FeO to water in the slurry is optionally and preferably selected to optimize physical and chemical processes in order to increase the performance of the obtained hydrogen.

[0193] FIG. 4 illustrates mechanisms 2-7 that can be applied externally to the physical and chemical processes in the chamber. The implementation of the first option for obtaining hydrogen from water is based on the use of cavitation treatment of a mixture of FeO and H2O in a vortex counterflow generator. As an external influence on the structure of flows in chamber 12 in the first option, one or more of mechanisms 2 through 7 may be employed. Mechanism 2 in FIG. 4 represents hydrodynamic action aimed at the formation of a resonance effect that determines the structure of flows. Mechanism 3 in FIG. 4 represents electrical action aimed at the separation of dissociated molecules in the structure of flows, the concentration of anions in the internal flow and cations in the external flow. Mechanism 5 in FIG. 4 represents a thermal action aimed at cavitation effects, chemical processes and hydrodynamic effects. Mechanism 5 in FIG. 4 represents electromagnetic action by external alternating electromagnetic fields aimed at intensifying processes in a vortex countercurrent reactor. Mechanism 6 in FIG. 4 represents chemical action, where the formation of a mixture of water and chemical reagents increases the rate of chemical reactions. Mechanism 7 in FIG. 4 represents acoustic action by acoustic frequency oscillations aimed at the formation and intensity of cavitation effects and the generation of anisotropic turbulent moths prevailing in the radial direction.

[0194] Use of a Vortex Hydrodynamic Cavitator for Obtaining Gaseous Hydrogen

[0195] The following effects of cavitation on chemical reactions are observed: (i) an increase in the speed of the reaction, (ii) an increase in the yield of target substances, (iii) an increase in the energy efficiency of the reaction, (iv) effects on interfacial transfer mechanisms, (v) activation of surface reactions, and (vi) activation of catalysts.In this Example, the production of hydrogen gas and peroxide compounds from water is recorded according to the scheme:

[0196] 2 · H2O = H2O2+ H2

[0197] The cavitation effect is accompanied by micro-explosions, ultrasound, as well as mechanical cuts and collisions under the influence of hundreds of cutting pairs moving towards each other at a high linear speed. When the cavitation bubbles generated by a liquid by a powerful ultrasonic wave, sonoluminescence occurs.

[0198] The classical mechanism of sonolysis (sonoluminescence) is based on a radical splitting of water inside the cavitation bubble, according to a simplified scheme, without taking into account solvation and energy transfer:

[0199] H2O = H · + · OH

[0200] When the bubble collapses, the resulting radicals or recombine:

[0201] 2 · H · = H2

[0202] 2 · (· OH) = H2O2

[0203] H · + · OH = H2O

[0204] or they are solvated by water molecules to form a solution, where they are recombined and interact with dissolved substances. In particular, the introduction of Fe2+ ions into the solution leads to their absorption of particles OH according to the following, simplified, scheme:

[0205] Fe2++ · OH = Fe3++ OH-

[0206] The resulting OH-ion is not capable of recombination with H, which shifts the system towards the reaction 2H = H2. This effect may not be sufficiently strong, since the resulting Fe3+ions are able to absorb H particles:

[0207] Fe3++ H · = Fe2++ H+

[0208] Thus, the Fe2+ion can be considered as a specific catalyst that extends the recombination process in time and removes the resulting energy. H · + · OH = H2O

[0209] It is assumed in this Example that the introduction of solid iron oxide FeO into cavitating water leads to one or more of: (z) radical binding • OH on the FeO surface with conversion to the OH-ion, (zz) distribution of the resulting positive charge over the FeO particle, which reduces the probability of the transformation of the H particle in H+, (zzz) retardation of type H recombination + • OH = H2O, which means a higher hydrogen yield; and (zv) acceleration of various reactions of FeO with water, with the formation of hydrogen (due to cavitation effects).When iron oxide powder FeO is added to the system, several chemical processes can occur: both increasing the yield of hydrogen and parasitic (consuming hydrogen or FeO). The chemical processes taking place in cavitation bubbles do not depend on the method by which cavitation is initiated. It is appreciated that for different chemical reactions, the optimal frequency can differ with respect to the yields of the target products. The types of reactions themselves do not depend on the frequency used: reactions begin to occur already at low frequencies of the order of units of hertz, and successfully go to the megahertz range. At a certain frequency threshold where cavitation does not occur, the reactions stop. The optimal frequency for output is optionally and preferably established experimentally.

[0210] The intensity of acoustic oscillations affects chemical processes in a nonlinear way: no reactions occur until the threshold power at which cavitation begins; this is followed by the power range, in which the reaction rate is proportional to the specific power of acoustic oscillations; and when a very significant power is reached, the rate of reactions, as well as the power of sonoluminescence and erosive activity, drops. The latter is related to the physics of cavitation itself: as the power increases, the size of the cavitation cavity increases, and the main effects of cavitation are associated with the last phases of bubble collapse. The collapse time is typically less than the halflife of the oscillations that cause the cavitation. Thus, large bubbles typically do not have time to collapse in half a period.

[0211] The temperature of the reaction mixture affects the efficiency of water decomposition. Increasing the temperature slows the reactions. In the present Example, the reaction is very fast, and the reaction zone itself is very narrow. The accompanying heating, therefore, does not significantly affect its speed. This assumption is based on the practical results obtained on the prototype of the plant - at its operating temperatures (about 800 °C), classical sonolysis of water by ultrasound does not occur (the limit temperature on classical installations is less than 500 °C), and in practice, noticeable volumes of hydrogen and peroxide are released.

[0212] Following are several chemical processes that are not directly related to the decomposition of water in cavitation bubbles.

[0213] Process 1: Oxidation of FeO oxide to Fe2O3 oxide with liquid water:

[0214] 2 · FeO + H2O (Liquid) → Fe2O3+ H2

[0215] This process provides maximum hydrogen yield per unit mass of iron oxide FeO. A thermodynamic analysis for normal conditions includes:

[0216] ΔG = ΔG0298(Fe2O3) - 2·ΔG0298(FeO) - ΔG0298(H2O(g)) =

[0217] = -740.337 - 2 (-244.299) - (-237.245) = -14.494 kJ / mol.A

[0218]

[0219] H = AH°298(Fe2O3) - 2AH°298(FeO) - AH°298(H2O(g)) =

[0220] = -822.156 - 2- (-264.847) -(-285.829) = -6.633 kJ / mol.

[0221] AS = AS0298(Fe2O3) + AS°298(H2) - 2AS°298(FeO) -AS°298(H2O(g)) =

[0222] = 87,445 + 130,519 - 2-60,751 - 70,082 = 26,38 J / mol.

[0223] The cases of AH < 0, AS > 0 and AG < 0 correspond to a reaction that can occur at any temperature. The reaction is exothermic, that is, it occurs with the release of heat.

[0224] In practice, this reaction proceeds very slowly due to the specific structure of iron oxide FeO, obtained during rapid cooling (the so-called "quenching"), which greatly reduces the reactivity of the resulting powder. Using cavitation, an increase in the reaction rate can be achieved due to grain fragmentation (increasing the active area and the number of active centers), as well as the interfacial transfer rate (knocking down insoluble Fe2O3 oxide and hydrogen bubbles from the surface of FeO oxide).

[0225] Process 2: Oxidation of FeO to Fe2O3 by water vapor formed in a cavitation bubble:

[0226] 2

[0227]

[0228] ■ FeO + H2O (Gas') Fe2O3+ H2

[0229] The thermodynamic functions for this process are:

[0230] AG = AG°298(Fe2O3) - 2AG°298(FeO) -AG°298(H2O(g)) =

[0231] = -740.337 - 2 (-244.299) - (-228.605) = -23.134 kJ / mol.

[0232] AH = AH0298(Fe2O3) - 2 AH°298(FeO) - AH0298(H2O(g)) =

[0233] =-822.156 -2 (-264.847) -(-241.818) = -50.644 kJ / mol.

[0234] AS = AS0298(Fe2O3) + AS°298(H2) - 2AS°298(FeO) -AS0298(H2O(g)) =

[0235] = 87,445 + 130,519 - 2 (60, 751) 188,723 = -92,261 J / mol.

[0236] The cases of AH < 0, AS > 0, and AG < 0 correspond to reactions that proceed at low temperatures. When the temperature rises to a certain threshold (equilibrium point), the reaction stops and begins to flow in the opposite direction.

[0237] When a cavitation bubble occurs, the vapor pressure in the bubble can reach thousands of atmospheres, in the complete absence of hydrogen. Thus, the partial pressure of the product (hydrogen) is negligible compared to the partial pressure of the initial substance. The almost instantaneous collapse of this bubble does not allow it to accumulate any significant amount of hydrogen necessary to start the reverse process. In cavitation, the equilibrium point can be expected to be different from what can be calculated from thermodynamic constants.This reaction can involve not only bubbles located on the surface of solid particles of FeO oxide, but also those located next to such a surface. By high-speed filming, it was recorded that the collapse of a cavitation bubble near the surface causes the ejection of a shaped charge jet in the direction of this surface (phenomena of cavitation erosion, dispersion and emulsification). Water vapor molecules are "hammered" into the FeO particles in such a stream, making reactive not only the surface layer, but also the atoms lying deeper.

[0238] Process 3: Oxidation of FeO oxide to Fe3O4 oxide with liquid water:

[0239] 3 ■ FeO + H2O Liquid -> Fe304+ H2

[0240] The thermodynamic functions for this process are:

[0241] AG =AG°298(Fe3O4) - 3 AG°298(FeO) -AG°298(H2O(g)) =

[0242] =-1014.163 - 3 (-244.299) - (-237.245) = -44.021 kJ / mol.

[0243] AH = AH0298(Fe3O4) - 3 AH°298(FeO) -AH°298(H2O(g)) =

[0244] = -1117.128 - 3 -(-264.847) -(-285.829) = -36.758 kJ / mol.

[0245] AS = AS0298(Fe3O4) + AS°298(H2) - 3AS°298(FeO) -AS°298(H2O(g)) =

[0246] = 146,188 + 130,519 - 3 (60, 751) 70,082 = 24,372 J / mol.

[0247] As in process 1, AH < 0, AS > 0 and AG < 0, which corresponds to a reaction that can take place at any temperature. Moreover, the course of this process is more profitable than process 1.

[0248] Process 4: oxidation of FeO oxide to Fe3O4 oxide by water vapor formed in a cavitation bubble:

[0249] 3

[0250]

[0251] ■ FeO + H2O (Gas) Fe304+ H2

[0252] The thermodynamic functions for this process are:

[0253] AG = AG°298(Fe3O4) - 3 AG°298(FeO) -AG°298(H2O(g)) =

[0254] = -1014.163 - 3 (-244.299) - (-228.605) = -52.661 kJ / mol.

[0255] AH = AH°298(Fe3O4) - 3 AH°298(FeO) - AH°298(H2O(g)) =

[0256] = -1117.128- 3-(-264.847) -(-241.818) = -80.769 kJ / mol.

[0257] AS = AS°298(Fe3O4) + AS°298(H2) - 3 AS°298(FeO) -AS0298(H2O(g)) = 146,188 +

[0258] 130,519 - 3(60,751) 188,723 = -94,269 J / mol.

[0259] As with process 2, AH < 0, AS > 0 and AG < 0, which corresponds to a process that takes place at low temperatures. The remarks on the effects of cavitation made for process 2 are valid in this case as well.Taking into account the fact that cavitation is accompanied by sharp temperature changes, and also causes a strong fragmentation of solids (up to a colloidal state), a chain of processes are considered.

[0260] Process 5:

[0261] 4

[0262]

[0263] ■ FeO Fe304+ Fe

[0264] Under normal conditions, this process occurs when the oxide FeO is freshly obtained, or with additional heating to 560-700 °C

[0265] Atomic iron reacts with water or steam:

[0266] 3

[0267]

[0268] - Fe + 4 - H2O Fe304+ 4 ■ H2

[0269] The latter reaction is an equilibrium, and the direction it proceeds depends on the concentration of water vapour and the hydrogen pressure. Taking into account the fact that iron appears at the boundary of the cavitation bubble, there is much more vapour than hydrogen, which shifts the equilibrium to the right, favouring the process that produces hydrogen.

[0270] Add these reactions, one obtains an alternative path for processes 3 and 4, and according to Hess's law the thermodynamics of the process does not depend on the path of the process.

[0271] Process 6: Oxidation of FeO with dissolved oxygen in the presence of water, with the formation of iron(III) oxide polyhydrate of variable composition (rust):

[0272] FeO + 2n ■ H2O + O2-> 2 ■ (Fe203+ n - H20)

[0273] This reaction consumes FeO oxide. Under normal conditions, the process is slow, which is due to the slow transit of oxygen to the surface and the poor solubility of the polyhydrate. Under cavitation conditions, this process is accelerated due to active mixing of water and mechanical removal of polyhydrate from the surface of the FeO oxide. However, the tightness of the unit will lead to the rapid depletion of dissolved oxygen. At the operating temperatures (about 800 °C) the solubility of oxygen in water does not exceed 3.6 mg per liter.

[0274] In all the processes described above, it should also be taken into account that cavitation generates a large number of excited water molecules H2O*, which are formed both directly, under bubble collapse conditions, and during particle recombination. The presence of such molecules always leads to the acceleration of reactions in which water is the initial substance. Excited H2O* molecules significantly aid in overcoming the activation barrier of the reaction and increase its speed.Energy released during the collapse of a water vapor bubble

[0275] During cavitation, an explosion of cavitation bubbles occurs, accompanied by the release of a large amount of energy, which contributes to the breaking of molecular bonds. Following is an estimated calculation of this energy.

[0276] For a molecule containing two (or more) identical bonds, a distinction is made between the chemical bond energy of each bond (bond breaking energy) and the average bond energy, which is equal to the average value of the bond breaking energy.

[0277] The energy of breaking the HO-H bond in a water molecule, is about 495 kJ / mol, the energy of breaking the H-0 bond in the hydroxyl group is about 435 kJ / mol, and the average energy of the chemical bond is about 465 kJ / mol. Note that the difference between the values of the energies of the break and the average energy of the chemical bond is due to the fact that during partial dissociation of a molecule (breaking of one bond), the electron configuration and relative position of the atoms remaining in the molecule change, as a result of which their interaction energy changes.

[0278] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0279] It is the intent of the applicant s) that all publications, patents and patent applications referred to in this specification are to be incorporated in their entirety by reference into the specification, as if each individual publication, patent or patent application was specifically and individually noted when referenced that it is to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting. In addition, any priority document(s) of this application is / are hereby incorporated herein by reference in its / their entirety.

Claims

WHAT IS CLAIMED IS:

1. A system for generating hydrogen, comprising:an elongated reaction chamber configured for receiving a slurry containing water and a redox active powder and forming oppositely directed flows of said slurry;a first outlet downstream of an inner flow of said flows, for discharging a first liquid stream comprising hydrogen enriched water and suspended reduced-form particulates derived from said redox active powder in a shear layer between said flows;a second outlet downstream of a peripheral flow of said flows, for discharging a second liquid stream comprising oxygen-enriched water and suspended oxidized-form particulates derived from said redox-active powder in said shear layer; anda power source configured to apply negative bias to said first outlet relative to said chamber.

2. The system according to any of claims 1, wherein said reaction chamber is cylindrical.

3. The system according to any of claims 1-2, further comprising a swirling apparatus at an inlet of said reaction chamber configured to impart swirl to said flows.

4. The system according to any of claims 1-3, wherein said flows are swirling about a common axis and have opposite mean axial components with said shear layer therebetween.

5. The system according to any of claims 1 -4, wherein said first outlet comprises a central tube aligned with a central axis of said reaction chamber.

6. The system according to any of claims 1-5, wherein said second outlet is arranged adjacent an inner surface of said reaction chamber to receive said peripheral flow.

7. The system according to any of claims 1-6, wherein said second outlet comprises separate outlets for venting a gaseous fraction and a mixture comprising oxidized-form particulates and water.

8. The system according to any of claims 1-7, wherein said chamber comprises an electrically conductive inner surface connected to said power source as an anode.

9. The system according to any of claims 1-8, wherein said power source comprises a direct current source.

10. The system according to any of claims 1-9, wherein said power source is configured to operate in a pulsed mode to modulate a potential of said first outlet relative to said reaction chamber.

11. The system according to any of claims 1-10, further comprising a magnetic field generator arranged to apply a magnetic field to said flows.

12. The system according to claim 11, wherein said magnetic field generator is configured to produce an axial magnetic field relative to a central axis of said reaction chamber.

13. The system according to any of claims 11 and 12, wherein said magnetic field generator is configured to produce a magnetic field having a radial gradient across said shear layer.

14. The system according to any of claims 1-13, wherein said redox active powder comprises a material selected from the group consisting of oxides and / or hydroxides of iron, manganese, cobalt, nickel, copper, vanadium, molybdenum, tungsten, or cerium, and mixtures thereof.

15. The system according to any of claims 1-13, wherein said redox active powder comprises a material selected from the group consisting of FeO, Fe3O4, Fe2O3, Fe(OH)2, Fe(OH)3, MnO, Mn3O4, Mn2O3, MnO2, Mn(0H)2, CoO, Co3O4, NiO, Ni(OH)2, Cu2O, CuO, V2O3, VO2, V2O5, MoO2, MoO3, WO2, WO3, Ce2O3, CeO2, and mixtures thereof.

16. The system according to any of claims 1-15, wherein said redox active powder comprises iron oxide FeO.

17. The system according to any of claims 1-16, wherein said suspended oxidized-form particulates comprise iron(III) oxide Fe2O3 and / or iron oxide Fe3O4.

18. The system according to any of claims 1-17, wherein said second liquid stream further comprises hydrogen peroxide.

19. The system according to any of claims 1-18, further comprising a hydrogen gas holder in fluid communication with said first outlet and an oxygen gas holder in fluid communication with said second outlet, each configured to accumulate respective gas separated from a respective liquid stream.

20. The system according to any of claims 19, further comprising a hydrogen compressor connected to said hydrogen gas holder and a hydrogen receiver connected to an outlet of said hydrogen compressor.

21. The system according to any of claims 19-20, further comprising an oxygen compressor connected to said oxygen gas holder and an oxygen receiver connected to an outlet of said oxygen compressor.

22. The system according to any of claims 19-21, wherein a portion of water from said gas holder connected to said second outlet is directed to said gas holder connected to said first outlet.

23. The system according to any of claims 1-21, further comprising a separator configured to separate water from oxidized-form particulates in said second liquid stream and a pump configured to return at least a portion of separated water to said reaction chamber.

24. The system according to any of claims 1-23, further comprising a mixer-dosing device configured to form said slurry from water supplied from a source water tank and said redox active powder supplied from a sealed hopper.

25. The system according to any of claims 1-24, further comprising an additional generator arranged upstream of said reaction chamber and configured to apply to said slurry at least one action selected from the group consisting of electrical discharge, acoustic action, electromagnetic action, thermal action, and chemical action.

26. The system according to claim 25, wherein said additional generator comprises at least one of: an acoustic transducer coupled to a wall of said reaction chamber, an electromagnetic coil arranged around said reaction chamber, and an electrical discharge source configured to act on said slurry upstream of said reaction chamber.

27. A method of generating hydrogen, comprising:forming within a reaction chamber having first and second outlets, oppositely directed flows of a slurry containing water and a redox active powder, with a shear layer between said flows;applying negative bias to said first outlet relative to said reaction chamber; discharging, downstream of an inner flow of said flows, through said first outlet, a first liquid stream comprising hydrogen enriched water and suspended reduced-form particulates derived from said redox active powder in said shear layer; anddischarging, downstream of a peripheral flow of said flows, through said second outlet, a second liquid stream comprising oxygen-enriched water and suspended oxidized-form particulates derived from said redox-active powder in said shear layer.

28. The method according to any of claims 27, wherein said flows are swirling about a common axis and have opposite mean axial components with said shear layer therebetween.

29. The method according to any of claims 27-28, further comprising forming said flows by introducing said slurry through a swirling apparatus at an inlet of said reaction chamber.

30. The method according to any of claims 27-29, wherein the negative bias is applied by applying a direct current electric potential between said first outlet and an electrically conductive inner surface of said reaction chamber.

31. The method according to any of claims 27-30, wherein the negative bias is applied by connecting an electrically conductive inner surface of said reaction chamber as an anode.

32. The method according to any of claims 27-31, further comprising applying a magnetic field to said flows using a magnetic field generator arranged to apply the magnetic field.

33. The method according to any of claims 27-32, wherein said redox active powder comprises a material selected from the group consisting of oxides and / or hydroxides of iron, manganese, cobalt, nickel, copper, vanadium, molybdenum, tungsten, or cerium, and mixtures thereof.

34. The method according to any of claims 27-32, wherein said redox active powder comprises a material selected from the group consisting of FeO, Fe3O4, Fe2O3, Fe(OH)2, Fe(OH)3, MnO, Mn3O4, Mn2O3, MnO2, Mn(OH)2, CoO, Co3O4, NiO, Ni(OH)2, Cu2O, CuO, V2O3, VO2, V2O5, MoO2, MoO3, WO2, WO3, Ce2O3, CeCh, and mixtures thereof.

35. The method according to any of claims 27-34, wherein said redox active powder comprises iron oxide FeO.

36. The method according to any of claims 27-35, wherein said suspended oxidized-form particulates comprise iron(III) oxide Fe2O3and / or iron oxide Fe3O4.

37. The method according to any of claims 27-36, wherein said second liquid stream further comprises hydrogen peroxide.

38. The method according to any of claims 27-37, further comprising forming said slurry by mixing water from a source water tank with said redox active powder supplied from a sealed hopper in a mixer-dosing device.

39. The method according to any of claims 27-38, further comprising collecting hydrogen separated from said first liquid stream in a hydrogen gas holder.

40. The method according to any of claims 27-39, further comprising compressing hydrogen collected from said first liquid stream with a hydrogen compressor and storing the compressed hydrogen in a hydrogen receiver.

41. The method according to any of claims 27-40, further comprising collecting oxygen separated from said second liquid stream in an oxygen gas holder.

42. The method according to any of claims 27-41, further comprising compressing oxygen collected from said second liquid stream with an oxygen compressor and storing the compressed oxygen in an oxygen receiver.

43. The method according to any of claims 27-42, further comprising separating water from oxidized-form particulates in said second liquid stream using a separator.

44. The method according to any of claims 27-43, further comprising returning at least a portion of water separated from said second liquid stream to said reaction chamber.

45. The method according to any of claims 27-44, further comprising applying to said slurry, upstream of entering said reaction chamber, at least one action selected from the group consisting of electrical discharge, acoustic action, electromagnetic action, thermal action, and chemical action using an additional generator arranged upstream of said reaction chamber.

46. The method according to any of claims 27-45, further comprising recirculating at least a portion of said slurry back to said reaction chamber.

47. The method according to any of claims 27-46, further comprising directing oxidized-form particulates from said second liquid stream to a regeneration process to form said redox active powder.

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