System and method for producing hydrogen from superheated steam

Abstract

The invention can be used in the creation of devices for producing hydrogen as a fuel, inter alia, at energy-intensive industrial facilities. What is proposed is a system for producing hydrogen from superheated steam comprising the following units: a generating unit consisting of the following elements arranged coaxially in a direction from the centre to the periphery: a central electrode, a cathode, a tube sealed at one end and made of a solid oxide electrolyte with oxygen ion conductivity, an anode, and permanent magnets; an electric power unit for supplying a voltage to the cathode, the anode and the central electrode; a control unit; and a gas measuring unit. The control unit receives data from the gas measuring unit and also engages in two-way communication with the electric power unit. The electric power unit, the control unit and the gas measuring unit are combined into a single unit that engages in two-way communication with the generating unit. The gas measuring unit is comprised of a system of sensors. Also proposed is a method for producing hydrogen using the claimed system. The group of inventions makes it possible to simplify the structure of a system for producing hydrogen, to regulate and automate the process, to conduct monitoring, to obtain controlled and efficient feedback, and to expand the existing range of energy-efficient means and methods for producing hydrogen.

Description

[0001] SYSTEM AND METHOD FOR PRODUCING HYDROGEN FROM SUPERHEATED WATER VAPOR

[0002] Field of technology

[0003] The proposed technical solution pertains to electrochemical engineering and can be used to create devices for producing hydrogen as a fuel, including at energy-intensive industrial facilities. Specifically, the proposed technical solution relates to a system and method for producing hydrogen from superheated water vapor.

[0004] State of the art

[0005] Industrial hydrogen production is an integral part of hydrogen energy, the first step in the hydrogen lifecycle. Hydrogen is rarely found in its pure form on Earth and must be extracted from other compounds using various chemical methods.

[0006] The electrolytic method of obtaining hydrogen from water is of great interest due to its simplicity and the high purity of the resulting gas components.

[0007] The electrolytic method of obtaining hydrogen from water has the following positive qualities: 1) high purity of the obtained hydrogen - up to 99.99% and higher, 2) simplicity of the technological process, its continuity, the possibility of the most complete automation, the absence of moving parts in the electrolytic cell, 3) the possibility of obtaining the most valuable by-products - heavy water and oxygen, 4) generally available and inexhaustible raw material - water, 5) flexibility of the process and the possibility of obtaining hydrogen directly under pressure, 6) physical separation of hydrogen and oxygen in the electrolysis process itself.

[0008] In this regard, there is a need to improve the means and methods for producing hydrogen, in particular electrolytic ones.

[0009] From Russian patent No. 2309198, published on 27.10.2007, a device is known for the electrolytic production of hydrogen and oxygen, comprising process lines for feeding water and electrolyte and removing electrolysis products, an electrolyzer including a housing with upper and lower covers made of an electrically conductive material, mounted on a shaft connected to a rotation drive with channels for feeding an electrolyte solution and removing electrolysis products, short-circuited electrodes, one of which is located on the shaft, and the other is formed by the inner surface of the housing, wherein the line for removing electrolysis products contains a device for pumping out electrolysis products and a separator connected in series, and the line for feeding water and electrolyte contains containers for water and electrolyte, a device for regulating the flow of water, valves, a mixer and a heat exchanger, see patent.The device is equipped with an electromagnetic system, including fixed magnets in the form of disks, installed in parallel above the upper and under the lower covers of the housing, a magnetic circuit mechanically connected to them with an excitation winding, electrically connected to a pulse generator and a voltage converter, a gas analyzer is installed on the line for removing electrolysis products, the input of which is connected to the output of the device for pumping out electrolysis products, and the output is connected to a device for regulating the flow of water, while a short-circuited electrode, located on the shaft, is made in the form of a cylinder with radial channels.

[0010] Also known is a device for the decomposition of water by electrolysis according to Russian Patent No. 2224051, published on 20.02.2004, comprising process lines for feeding water and electrolyte and removing electrolysis products, an electrolyzer including a housing mounted on a shaft connected to a rotation drive with channels for supplying an electrolyte solution and removing electrolysis products, a channel for removing the electrolyte solution, short-circuited electrodes, one of which is located on the shaft, and the other is formed by the inner surface of the housing, and a heat exchanger, as well as upper and lower bearing assemblies in which the shaft is vertically located. The external circuit for the circulation of the electrolyte solution contains an annular chamber of the electrolyte solution with an inner surface in the form of a snail, fixedly mounted on the upper bearing assembly, a sensor for the presence of an electrolyte solution and an electrolyte solution mixer connected to the electrolyte and water supply lines and the channel for supplying the electrolyte solution,The electrolyzer housing is made of a conductive material and is provided with a lower and upper cover made of a conductive material, a channel for draining the electrolyte solution is formed in the upper cover and is provided with an adjustable valve communicating with the annular chamber of the electrolyte solution, the inner surface of the housing is provided with at least one guide groove, the water supply line is provided with a water flow control device, the electrolysis product discharge line is provided with a device for pumping out the electrolysis products, a heat exchanger is located in the external circuit of the electrolyte solution circulation, and an electrolyte solution presence sensor is connected to the water flow control device and the shaft rotation drive. The disadvantages of the known installation include the complexity of the design and low productivity.

[0011] The closest analog to the claimed solutions is the one described in Russian Patent No. 2675862, published December 25, 2018, relating to a method for decomposing water into oxygen and hydrogen and a device for implementing the method. The method is implemented by exposing water flowing through interelectrode cavities to electric and magnetic fields. A constant pulsed electric field is applied to coaxially arranged tubular insulated hydrogen electrodes of negative potential and to insulated oxygen electrodes of positive potential, separated by interelectrode cavities having inlet and outlet water openings, the volumes of which are connected to the volumes of the hydrogen and oxygen electrodes through gas openings.As a result, water flowing between the electrodes is decomposed into hydrogen and oxygen ions under the influence of electric and magnetic fields. Hydrogen ions are attracted through the openings of the hydrogen electrode by the negative static field generated by the negative conductive insulated hydrogen surface into the hydrogen electrode. Similarly, oxygen ions are attracted through the openings of the oxygen electrode by the positive static field generated by the positive conductive insulated surface into the oxygen electrode. The hydrogen and oxygen ions are neutralized by the negative and positive neutralization surfaces, respectively, and exit through each opening as atoms for further use. Disadvantages of known solutions include the complex design of the system, high energy consumption for hydrogen production, and the inability to regulate the hydrogen production process.

[0012] The objective of the proposed inventions is to eliminate the shortcomings of the prior art, simplify the design of the hydrogen production system and method, enable process regulation, automation, control, obtain controlled effective feedback, and expand the range of energy-efficient means and methods for producing hydrogen.

[0013] List of figures

[0014] Fig. 1 shows a diagram of a system for producing hydrogen from superheated water vapor.

[0015] Fig. 2 shows the external appearance of the experimental research setup in assembled form.

[0016] Disclosure of invention

[0017] The technical result of the group of inventions is a simplification of the design of the hydrogen production system and method, the possibility of process regulation, automation, control, obtaining controlled effective feedback, increasing the scalability and efficiency of gas-tight separation of the anode and cathode gas spaces, mass transfer and heat transfer, expanding the range of energy-efficient means and methods for producing hydrogen.

[0018] To achieve the stated technical task and obtain the technical result, a method for producing hydrogen from superheated water vapor and a system for its implementation are proposed.

[0019] The proposed system for producing hydrogen (Hg) from superheated water vapor includes the following units:

[0020] - a generating unit (1) consisting of the following located coaxially in the direction from the center to the periphery: a central electrode (8), a cathode (7), a tube sealed at one end made of solid oxide electrolyte with ionic conductivity of oxygen (5), an anode (6) and permanent magnets (9);

[0021] - a power electrical unit (2) that supplies voltage to the cathode, anode and central electrode; - a control unit (3);

[0022] - a measuring gas block (4), wherein the control unit receives data from the measuring gas block and also carries out two-way interaction with the power electrical unit.

[0023] In a particular embodiment of the system, blocks (2), (3) and (4) are combined into one block, which carries out two-way interaction with the generating block (1).

[0024] The proposed method for producing hydrogen ( ) from superheated water vapor includes the following stages:

[0025] - superheated (500-950°C) water (H2O) vapor is fed through the central electrode (8) into a tube of solid oxide electrolyte with ionic conductivity of oxygen (5);

[0026] - superheated water vapor hits the cathode (7);

[0027] - using a power electrical unit (2), a pulsed voltage is applied between the cathode (7) and the central electrode (8), resulting in a partial decomposition of water vapor into oxygen ions and hydrogen ions;

[0028] - part of the water vapor, hitting the cathode (7), loses an oxygen ion;

[0029] - oxygen ions, under the influence of the potential difference between the cathode (7) and the anode (6), pass through a tube of solid oxide electrolyte with ionic conductivity of oxygen (5) and exit from the other side in the form of pure oxygen, which enters the measuring gas block (4);

[0030] - hydrogen remaining in the tube of solid oxide electrolyte with ionic conductivity of oxygen (5) enters the measuring gas block (4);

[0031] - oxygen and hydrogen from the measuring gas block (4) then enter the external storage system; in this case, the characteristics of the pulse voltage between the cathode (7) and the central electrode (8) and the voltage between the cathode (7) and the anode (6) are set by the control unit (3), and in order to stabilize the characteristics of the pulse voltage between the cathode (7) and the central electrode (8), a constant magnetic field is created around the tube of solid oxide electrolyte with ionic conductivity of oxygen (5) using permanent magnets (9).

[0032] Below is a detailed description of the proposed development and options for its implementation.

[0033] Solid oxide electrolyte with ionic oxygen conductivity (5) is a solid-state ion-conducting membrane. Ionic oxygen conductivity is caused by the disruption of the crystal lattice upon the introduction of an impurity into it and manifests itself in the temperature range of 500-950°C. Material options for the solid oxide electrolyte (5): yttria-stabilized zirconium oxide (YSZ); scandium oxide-stabilized zirconium oxide (ScSZ); lanthanum gallate (LSGM); gadolinium-doped cerium oxide (GDC), etc.

[0034] A tube made of solid oxide electrolyte with ionic conductivity of oxygen (5) is sealed at one end to form a bottom, which is necessary to increase the effective surface area of ​​the solid-state ion-conducting membrane, as well as to increase the structural strength of the generating unit (1).

[0035] To stabilize the characteristics of the pulse voltage between the cathode (7) and the central electrode (8), a constant magnetic field is created by permanent magnets (9).

[0036] Options for materials for permanent magnets (9): neodymium-iron-boron, samarium-cobalt, alnico (UNDK, based on the Al-Ni-Co-Fe alloy), ceramics (barium, strontium hard magnetic ferrites), etc.

[0037] The power electrical unit (2) supplies unipolar positive pulses to the central electrode (8): with a frequency in the range of 40 Hz - 1.5 MHz; with a duty cycle in the range of 10-90; with a current of up to 50 A; with a voltage in the range of 10-50 V.

[0038] The power electrical unit (2) supplies a constant voltage in the range of 5-20 V, with a current of up to 100 A, to the cathode (7) and anode (6).

[0039] The power electrical unit (2) measures and transmits to the control unit (3) data on the actual operating mode: voltage, current, resonant frequency, etc. Options for materials for the cathode (7), anode (6), central electrode (8): platinum; palladium; gold; platinum-coated nickel sponge; silicon carbide; graphite; graphene; platinum-nickel-based metal ceramics (nickel cermet); metal / metal ceramics (lanthanum chromite); lanthanum strontium manganite, etc.

[0040] The measuring gas unit (4) measures and transmits to the control unit (3): temperature of hydrogen and oxygen gases; partial pressure of hydrogen and oxygen gases; quantity of hydrogen and oxygen gases over a period of time; relative humidity of hydrogen and oxygen gases (residual water vapor), etc. A system of sensors is used as a measuring gas unit.

[0041] The control (processor) unit (3), based on the data received from the measuring gas unit (4) and the power electric unit (2), analyzes and controls the energy efficiency of the system as a whole - implements controlled effective feedback.

[0042] The control unit (3) transmits data about the planned operating mode to the power unit (2): voltage, current, pulse characteristics (frequency, duty cycle), etc.

[0043] The coaxial arrangement of the generating unit elements (1) increases scalability and efficiency: gas-tight separation of the anode and cathode gas spaces; mass transfer and heat transfer.

[0044] The combination of primary resonant pulse electrolysis of water vapor and electrolysis of water vapor through a solid-state ion-conducting membrane (5) allows for a significant reduction in energy costs for the electrolysis of water vapor.

[0045] Heating the solid-state membrane (5) to operating temperature is achieved by using the heat of superheated steam. Superheated steam is produced by recovering heat from solar collectors or heat-generating / heat-emitting systems, such as thermal power plants, waste incineration plants, blast furnaces, etc.

[0046] Since water vapor is fed into the system under pressure generated by heating, this allows for the creation of effective filters for purifying hydrogen of residual water vapor and facilitates the supply of hydrogen to an external storage system. The proposed system / method is highly scalable: it enables the creation of miniature solutions, high-performance solutions, and both industrial and consumer solutions.

[0047] The originality of the proposed solution: 1) in the coaxial scheme of combining the above solutions, 2) in the use of permanent magnets to stabilize the characteristics of the resonant pulse voltage, 3) in the use of a control (processor) unit to obtain controlled effective feedback.

[0048] Implementation of the invention

[0049] The proposed system and method are currently implemented in an experimental research installation for hydrogen generation with a capacity of 0.02-0.05 m 3 / hour LANEMATEC HYDX EHG-01.

[0050] The external appearance of the assembled experimental research setup is shown in Fig. 2.

[0051] The installation corresponds to the drawing presented in the application (Fig. 1) and includes: a superheated steam generation unit, a generating unit consisting of coaxially arranged: a tube made of zirconium oxide stabilized with yttrium oxide, sealed at one end, an anode, a cathode, a central electrode made of graphite and permanent magnets neodymium-iron-boron; a power electrical unit, a control unit (computer); a measuring gas unit, a sensor system.

[0052] From the superheated steam generation unit, water vapor superheated to a temperature of approximately 700°C is fed through the central electrode into a tube made of solid oxide electrolyte with oxygen ion conductivity; the superheated water vapor reaches the cathode; a pulsed voltage is applied between the cathode and the central electrode using the power electrical unit, resulting in partial decomposition of the water vapor into oxygen ions and hydrogen ions; some of the water vapor, reaching the cathode, loses an oxygen ion; the oxygen ions, under the action of the potential difference between the cathode and the anode, pass through the tube made of solid oxide electrolyte with oxygen ion conductivity and exit on the other side as pure oxygen, which enters the measuring gas block; the hydrogen remaining in the tube made of solid oxide electrolyte with oxygen ion conductivity enters the measuring gas block;Oxygen and hydrogen from the measuring gas block then enter the external storage system. The characteristics of the pulse voltage between the cathode and central electrode and the voltage between the cathode and anode are set by the computer (control unit). To stabilize the characteristics of the pulse voltage between the cathode and central electrode, a constant magnetic field is created around the solid oxide electrolyte tube with ionic oxygen conductivity using permanent magnets.

[0053] The tests carried out on the LANEMATEC HYDX EHG-01 experimental research unit confirmed the unit’s operational capability and its industrial applicability.

[0054] This system and method provide a 5-12-fold increase in energy efficiency by reducing energy costs for electrolysis. Up to 0.5-1 kWh per m 3 (water-alkaline low-temperature electrolysis: 5.0-6.0 kW*h per m 3 Ng).

[0055] The system and method utilize superheated water vapor obtained by utilizing excess cheap / free heat: in thermal power plants, high-temperature nuclear gas-cooled reactors (HTGR), waste incineration plants, blast furnaces, etc.; and solar energy utilization. Technically, this efficiency is achieved through more efficient decomposition of superheated water vapor (into oxygen ions and hydrogen ions) by pulsed voltage and through more efficient operation of a solid oxide electrolyte with oxygen ion conductivity, the operating temperature of which (500-950°C) is maintained by the temperature of the superheated vapor and no electrical energy is consumed for heating. This system and method provide high technological efficiency: a 10-20-fold reduction in volumetric mass characteristics; a 4-8-fold increase in overall performance in terms of current density: 2-2.5 A / cm 2(water-alkaline low-temperature electrolysis: current density 0.3 -0.5 A / cm 2 ); scalability (increased overall productivity) through the simple installation of additional modules; high temperatures make electrolysis less sensitive to water purity; high temperatures increase overall productivity by increasing the process speed; more efficient hydrogen filtration and more efficient hydrogen supply to the storage system due to the pressure of superheated steam. Full automation and the ability to adjust the hydrogen production process, its quality, and quantity are also achieved.

Claims

CLAUSES OF THE INVENTION 1. A system for producing hydrogen from superheated water vapor, including the following units: - a generating unit consisting of a central electrode, a cathode, a tube made of solid oxide electrolyte with ionic conductivity of oxygen, an anode and permanent magnets, located coaxially in the direction from the center to the periphery; - a power electrical unit that supplies voltage to the cathode, anode and central electrode; - control unit; - a measuring gas block; the control unit receives data from the measuring gas block and also carries out two-way interaction with the power electrical unit.

2. The system according to item 1, characterized in that the power electrical unit, control unit, and measuring gas unit are combined into one unit that performs two-way interaction with the generating unit.

3. The system according to item 1 or 2, characterized in that the measuring gas unit is a sensor system.

4. A method for producing hydrogen from superheated water vapor using the system according to I. 1, comprising the following stages: - superheated water vapor with a temperature of 500-950°C is fed through the central electrode into a tube made of solid oxide electrolyte with ionic conductivity of oxygen, sealed at one end; - superheated water vapor hits the cathode; - using a power electrical unit, a pulsed voltage is applied between the cathode and the central electrode to partially decompose water vapor into oxygen ions and hydrogen ions; - part of the water vapor, getting to the cathode, loses an oxygen ion; - oxygen ions, under the influence of the potential difference between the cathode and the anode, pass through a tube of solid oxide electrolyte with ionic conductivity of oxygen and exit from the other side in the form of pure oxygen, which is directed into the measuring gas block; - hydrogen remaining in the tube of solid oxide electrolyte with ionic conductivity of oxygen is also directed into the measuring gas block; - oxygen and hydrogen from the measuring gas block are then sent to an external storage system; in this case, the characteristics of the pulse voltage between the cathode and the central electrode and the voltage between the cathode and the anode are set by the control unit, and to stabilize the characteristics of the pulse voltage between the cathode and the central electrode, a constant magnetic field is created around the tube of solid oxide electrolyte with ionic conductivity of oxygen using permanent magnets.

5. The method according to item 4, characterized in that the measuring gas unit is a system of sensors.

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