Rotary compression type concentrating solar water splitting hydrogen production reactor

Abstract

The invention discloses a rotary compression type concentrating solar water splitting hydrogen production reactor, relates to the technical field of energy conversion and storage, and solves the problems that a traditional solar hydrogen production mode is low in efficiency and the hydrogen solid phase heat regeneration process is complex. A plurality of hydrogen production reactors are connected to a shaft in series, and the hydrogen production reactors are used in cooperation with an external solar condenser; the hydrogen production reactor comprises a front end cover, a rear end cover, a rotor, a reaction chamber and a cam; the front end cover, the reaction chamber and the rear end cover are connected in sequence; rotors are arranged in the reaction chamber and divide the reaction chamber into a plurality of chambers; the rotor is arranged on the shaft through the cam; a quartz window and air holes are formed in the reaction chamber, sunlight radiation collected by the solar condenser is transmitted into the reaction chamber through the quartz window, and gas exchange is performed through the air holes; and a cerium oxide oxygen carrier is arranged on the rotor. By optimizing the solid-phase heat regeneration process of the oxygen carrier, the structure of the reactor is remarkably simplified, and efficient conversion from solar energy to hydrogen energy is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of energy conversion and storage, and in particular to a rotary compression type concentrated solar water splitting hydrogen production reactor. Background Art

[0002] With the continuous growth of global energy demand and the increasingly severe environmental problems, the search and development of clean and renewable energy technologies has become a research hotspot in the global energy field. Hydrogen energy is a clean, efficient and renewable energy source. Hydrogen is widely distributed and has abundant reserves in the earth's water bodies; hydrogen has a high combustion calorific value and has advantages in energy density; at the same time, its combustion product is only water, which is a zero-pollution energy. Therefore, it has great potential in energy transformation and carbon emission reduction. Traditional fossil energy hydrogen production methods have problems such as low efficiency, environmental pollution and resource limitations. Therefore, it is particularly important to develop new clean energy hydrogen production technologies.

[0003] As an almost inexhaustible renewable energy, solar energy is considered to be an important part of the future energy structure for its clean and environmentally friendly characteristics. Thermochemical hydrogen production using solar energy, that is, decomposing water into hydrogen and oxygen through a chemical reaction driven by solar energy, is a technology with broad application prospects. There are currently several different approaches: photoelectrochemical decomposition hydrogen production, photocatalytic hydrogen production and thermochemical hydrogen production. Photoelectrochemical decomposition is a photoelectrochemical cell composed of a photoanode and a cathode. In the presence of an electrolyte, the electrons generated by the photoanode after absorbing light flow to the cathode, and the hydrogen ions in the water accept the electrons to produce hydrogen. This requires a semiconductor photoanode, such as TiO2, but the efficiency still needs to be improved; photocatalytic hydrogen production is the use of photocatalysts under certain light conditions to catalytically decompose water to produce hydrogen, and the current efficiency is low; thermochemical hydrogen production uses a solar concentrator to generate a high-temperature heat source to drive the oxidation-reduction cycle of metal oxide oxygen carriers, and decomposes water into hydrogen and oxygen in a two-step reaction. However, the hydrogen-oxygen separation problem and the oxygen carrier heat recovery problem of the traditional rotary solar hydrogen production reactor are still the main factors limiting the efficiency of hydrogen production.

[0004] Traditional solar thermochemical reactors usually adopt fixed bed or fluidized bed designs, which have certain limitations in high temperature operation and circulation of solid oxygen carriers. For example, high temperature operation requires the reactor material to have excellent high temperature resistance and good corrosion resistance, which often leads to increased equipment costs. At the same time, the heat recovery process of the oxygen carrier is complicated, the thermal efficiency is not high, and the equipment structure and operation control are relatively complex, making it difficult to achieve large-scale application. Summary of the invention

[0005] In order to solve the problems of low efficiency and complicated solid-phase heat recovery process of hydrogen in traditional solar hydrogen production methods mentioned above, the present invention proposes a rotary compression concentrated solar water splitting hydrogen production reactor. The present invention significantly simplifies the reactor structure by optimizing the solid-phase heat recovery process of the oxygen carrier, and realizes efficient conversion of solar energy to hydrogen energy.

[0006] The present invention proposes a rotary compression type concentrated solar water splitting hydrogen production reactor, which specifically comprises a front end cover, a rear end cover, a rotor, a shaft, a reaction chamber, a cam and a solar concentrator; the front end cover, the reaction chamber and the rear end cover are connected in sequence; a rotor is arranged in the reaction chamber, and the rotor divides the cavity in the reaction chamber into a plurality of chambers; the rotor is arranged on the shaft through the cam; a quartz window and a solar concentrator are arranged on the reaction chamber, and the solar radiation collected by the solar concentrator is transmitted into the reaction chamber through the quartz window; four air holes are arranged on the reaction chamber, and gas exchange is performed through the air holes; cerium oxide is arranged on the rotor; and a plurality of rotary compression type concentrated solar water splitting hydrogen production reactors are connected in series on the shaft.

[0007] Furthermore, the rotor is a Lello triangle structure.

[0008] Furthermore, a seal is provided between the rotor apex and the inner wall of the reaction chamber.

[0009] Furthermore, each arc surface of the rotor is provided with a groove, and cerium oxide is provided in the groove.

[0010] Furthermore, the cerium oxide is made into a porous structure by pressing.

[0011] Furthermore, the front end cover is provided with a sealing gear, which is sleeved on the shaft; the rotor is provided with an internal gear, which is meshed with the sealing gear.

[0012] Furthermore, the rotors of the plurality of rotary compression-type concentrated solar water splitting hydrogen production reactors connected in series on the shaft are installed at different phases.

[0013] The beneficial effects of the rotary compression concentrated solar water splitting hydrogen production reactor described in the present invention are:

[0014] (1) The rotary compression concentrated solar water splitting hydrogen production reactor described in the present invention overcomes the problem of low efficiency of traditional solar hydrogen production methods. Under typical conditions (solar concentration ratio of 3000, reduction temperature of 1773K, oxidation temperature of 1073K, gas phase heat recovery efficiency of 0.9, mechanical energy recovery efficiency of 0.85, and molar flow ratio of purge gas to cerium oxide of 10), a rotary reactor with a Lello triangular rotor and a geometric compression ratio of 13 can achieve an optimal solar-to-chemical energy conversion efficiency of 17%;

[0015] (2) The rotary compression concentrated solar water splitting hydrogen production reactor described in the present invention overcomes the difficulty of separating hydrogen and oxygen. The entire redox cycle is divided into an endothermic reduction reaction and an exothermic oxidation reaction by setting a rotary reactor. When the rotor rotates to different phases, different gases are injected into the reaction chamber through the four air holes, so that hydrogen and oxygen are produced in different stages, thereby avoiding the mixing of hydrogen and oxygen.

[0016] (3) The rotary compression concentrated solar water splitting hydrogen production reactor described in the present invention overcomes the problem of complex solid-phase heat recovery process. A plurality of hydrogen production reactors are connected in series on the shaft. The rotors of the plurality of hydrogen production reactors are installed on the shaft through cams and the installation phases are different. When the gas expands, the rotor does work on the shaft. When the gas is compressed, the shaft needs to do work on the rotor. Through the energy exchange of different phase cycles, the internal gear and the sealing gear arranged on the rotor are meshed. The sealing gear drives the shaft to rotate, and the solid-phase sensible heat between the oxidation and reduction thermodynamic states is recovered in the form of mechanical energy. At the same time, the solar energy-to-fuel conversion efficiency is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] In the attached picture:

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of a rotary compression concentrated solar water splitting hydrogen production reactor according to the present invention;

[0020] Figure 2 This is a structural exploded view of a rotary compression concentrated solar water splitting hydrogen production reactor according to the present invention;

[0021] Figure 3 It is a structural schematic diagram of a rotor of a rotary compression type concentrated solar water splitting hydrogen production reactor according to the present invention;

[0022] Figure 4 It is a structural schematic diagram of a reaction chamber of a rotary compression type concentrated solar water splitting hydrogen production reactor according to the present invention;

[0023] Figure 5 It is a structural schematic diagram of the shaft and cam of a rotary compression type concentrated solar water splitting hydrogen production reactor according to the present invention;

[0024] Figure 6 It is a structural schematic diagram of a sealing gear of a rotary compression type concentrated solar water splitting hydrogen production reactor according to the present invention;

[0025] Figure 7 It is a schematic diagram of the gas path of the reaction chamber of a rotary compression type concentrated solar water splitting hydrogen production reactor according to the present invention;

[0026] Among them: 1-front cover; 2-rear cover; 3-sealing gear; 4-rotor; 5-shaft; 6-reaction chamber; 7-quartz window; 8-scavenging port; 9-cam. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0029] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0030] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] Specific implementation method 1: See Figure 1-Figure 7The present embodiment is described in detail. The rotary compression concentrated solar water splitting hydrogen production reactor described in the present embodiment specifically comprises a front cover 1, a rear cover 2, a rotor 4, a shaft 5, a reaction chamber 6, a cam 9 and a solar concentrator. The front cover 1, the reaction chamber 6 and the rear cover 2 are connected in sequence; a rotor 4 is arranged in the reaction chamber 6, and the rotor 4 divides the cavity in the reaction chamber 6 into a plurality of chambers; the rotor 4 is arranged on the shaft 5 through the cam 9, so that the rotor 4 can rotate in the reaction chamber 6 to perform eccentric planetary motion; the rotor 4 and the reaction chamber 6 are in sliding contact, and the reaction chamber 6 is sealed from front to back through the front cover 1 and the rear cover 2. The rotor 4 and the reaction chamber 6 are sealed, and the volume of each chamber changes periodically with the rotation of the rotor 4 through the relative movement of the rotor 4; the reaction chamber 6 is provided with a quartz window 7 and a solar concentrator, and the solar radiation collected by the solar concentrator is transmitted to the reaction chamber 6 through the quartz window 7 to provide heat for the reduction reaction; the reaction chamber 6 is provided with four air holes 8, and the gas in the reaction chamber 6 is exchanged through the air holes 8; the rotor 4 is provided with cerium oxide, and hydrogen and oxygen are prepared through cerium oxide; a plurality of rotary compression concentrated solar water splitting hydrogen production reactors are connected in series on the shaft 5.

[0032] The rotor 4 is a Lello triangle structure; the rotor 4 with a Lello triangle prism structure and the elliptical outer shell of the reaction chamber 6 constitute the present reactor, the vertex of the rotor 4 is in dynamic contact with the outer shell of the reaction chamber 6, the side surface of the rotor 4 is arc-shaped, and three independent reaction chambers are formed between the outer shell of the reaction chamber 6, and the reaction chamber is sealed at the vertex of the rotor 4 away from the cerium oxide using a seal.

[0033] Each arc surface of the rotor 4 is provided with a groove, and cerium oxide is provided in the groove. The cerium oxide is pressed into a porous structure to improve the absorption efficiency of solar energy.

[0034] The front end cover 1 is provided with a sealing gear 3, which is sleeved on the shaft 5; the rotor 4 is provided with an internal gear, which meshes with the sealing gear 3. The rotors 4 of the plurality of rotary compression concentrated solar water splitting hydrogen production reactors connected in series on the shaft 5 are installed at different phases. When the gas in the reaction chamber 6 of a part of the hydrogen production reactor expands, the gas does work on the rotor 4, and the rotor 4 drives the sealing gear 3 through the internal gear, and the sealing gear 3 drives the shaft 5 to rotate, and the power is transferred to the rotor 4 of another part of the hydrogen production reactor through the shaft 5 for gas compression; the energy exchange cycle is realized by installing the rotor 4 in different phases.

[0035] The specific working principle of the rotary compression concentrated solar water splitting hydrogen production reactor described in the present invention is:

[0036] Among the various metal oxides studied, cerium was selected as the reference material for this reactor because of its fast kinetics and rich thermodynamic data. The redox cycle includes an endothermic reduction reaction and an exothermic oxidation reaction, and the reaction formula is:

[0037]

[0038] like Figure 7 As shown, the rotor 4 rotates clockwise. For the cerium oxide on each curved surface of the rotor 4, the rotation can be divided into three stages according to the different phases:

[0039] In the first stage, solar radiation is concentrated into the reaction chamber through the quartz window 7. A groove of the rotor and the cerium oxide are located opposite the quartz window. This is considered the initial phase. The nitrogen in the reaction chamber is compressed to the minimum volume of the entire cycle, and the cerium oxide is reduced. In this stage, the reaction chamber reaches the highest pressure and the highest temperature of the entire cycle. Then, as the rotor 4 rotates, the cerium oxide leaves the solar radiation irradiation area. Due to the expansion of the gas, the temperature in the reaction chamber drops to near the oxidation temperature, and the pressure drops to near the ambient pressure. The nitrogen is used to purge the oxygen generated in the reduction stage.

[0040] In the second and third stages, the rotor rotates to the 2π / 3 and 4π / 3 phases, and the reaction chamber is purged of excess steam through two pairs of air holes 8 on the reaction chamber 6. The reduced cerium oxide is reoxidized by the excess steam at ambient pressure, and the generated hydrogen is purged out with the excess steam. Finally, before returning to the first stage, the reaction chamber is purged with pure nitrogen and heated to the reduction temperature by mechanical compression.

[0041] Correspondingly, the same cycle is carried out in the remaining two reaction chambers, with phase lags of 2π / 3 and 4π / 3 respectively.

[0042] The compression process has a contradictory effect on the reactor. When the equilibrium oxygen partial pressure is reached, on the one hand, it makes the cerium oxide easier to heat, but on the other hand, it reduces the degree of reduction reaction. In fact, when compressed, the reduction reaction reaches equilibrium in a shorter time. The loss of oxygen release per unit mass of cerium oxide can be compensated by increasing the rotation speed. Taking into account the convenience of heating by compression, the compression process is adopted before the reduction stage.

[0043] The compression process requires input of work to the system, and the expansion process requires work to be done by the system on the environment. The cyclic energy exchange provides a method for recovering solid-phase sensible heat between different thermodynamic states in the oxidation and reduction phases in the form of mechanical energy. Connecting multiple rotors running in different phases to the same shaft 5 can make the cyclic energy exchange smoother. Therefore, the reactor can be smoothly compressed and expanded periodically, and solid-phase heat can be recovered in the form of mechanical energy.

[0044] Under typical conditions (when the solar concentration ratio is 3000, the reduction temperature is 1773K, the oxidation temperature is 1073K, the gas phase heat recovery efficiency is 0.9, the mechanical energy recovery efficiency is 0.85, and the molar flow ratio of the purge gas to the ceria is 10), the solar-to-fuel conversion efficiency is 13.2%. The efficiency can be significantly improved by increasing the solar concentration ratio, the reduction temperature, the gas phase and mechanical energy recovery efficiencies, and reducing the molar flow ratio of the purge gas to the ceria.

[0045] This reactor is best suited for dish-type solar concentrator systems with a solar concentration ratio of 3000. If installed in a tower system with a solar concentration ratio of 1000, the efficiency will drop significantly; and increasing the solar concentration ratio to more than 3000 will only slightly increase the efficiency.

[0046] The reactor performs solid-phase heat recovery on cerium oxide without affecting its solar energy-to-fuel conversion rate.

[0047] To summarize the above implementation cases, the rotary compression type concentrated solar water splitting hydrogen production reactor described in the present invention overcomes the problem of low efficiency of traditional solar hydrogen production methods. Under typical conditions (solar concentration ratio of 3000, reduction temperature of 1773K, oxidation temperature of 1073K, gas phase heat recovery efficiency of 0.9, mechanical energy recovery efficiency of 0.85 and molar flow ratio of purge gas to cerium oxide of 10), a rotary reactor with a rotor 4 of a Lello triangle structure and a geometric compression ratio of 13 is used. The system can achieve an optimal solar energy-to-chemical energy conversion efficiency of 17%; the rotary compression type concentrated solar water splitting hydrogen production reactor described in the present invention overcomes the problem of difficulty in separating hydrogen and oxygen. The entire redox cycle is divided into an endothermic reduction reaction and an exothermic oxidation reaction by setting a rotary reactor. Through the four air holes 8, different gases are injected into the reaction chamber 6 when the rotor 4 rotates to different phases, so that hydrogen and oxygen are produced at different stages, thereby avoiding the mixing of hydrogen and oxygen. The rotary compression concentrated solar water splitting hydrogen production reactor described in the present invention overcomes the problem of complex solid-phase heat recovery process. By connecting a plurality of hydrogen production reactors in series on the shaft 5, the rotors 4 of the plurality of hydrogen production reactors are installed on the shaft 5 through the cam 9 and the installation phases are different. When the gas expands, the rotor 4 does work on the shaft 5. When the gas is compressed, the shaft 5 needs to do work on the rotor 4. Through the energy exchange of different phase cycles, the internal gear arranged on the rotor 4 is meshed with the sealing gear 3, and the sealing gear 3 drives the shaft 5 to rotate, so as to recover the solid-phase sensible heat between the oxidation and reduction thermodynamic states in the form of mechanical energy, and at the same time does not affect the solar energy-fuel conversion efficiency.

[0048] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the invention. It can also be a reasonable combination of the features recorded in the above implementation methods. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A rotary compression concentrated solar water splitting hydrogen production reactor, characterized in that: The invention comprises a front end cover (1), a rear end cover (2), a rotor (4), a shaft (5), a reaction chamber (6), a cam (9) and a solar concentrator; the front end cover (1), the reaction chamber (6) and the rear end cover (2) are connected in sequence; a rotor (4) is arranged in the reaction chamber (6), and the rotor (4) divides the cavity in the reaction chamber (6) into a plurality of chambers; the rotor (4) is arranged on the shaft (5) through the cam (9); a quartz window (7) and a solar concentrator are arranged in the reaction chamber (6), and the solar radiation collected by the solar concentrator is transmitted to the reaction chamber (6) through the quartz window (7); four air holes (8) are arranged in the reaction chamber (6), and gas exchange is carried out through the air holes (8); cerium oxide is arranged on the rotor (4); and a plurality of rotary compression type concentrated solar water splitting hydrogen production reactors are connected in series on the shaft (5).

2. The rotary compression concentrated solar water splitting hydrogen production reactor according to claim 1, characterized in that: The rotor (4) is a Lello triangle structure.

3. The rotary compression concentrated solar water splitting hydrogen production reactor according to claim 1 or 2, characterized in that: A seal is provided between the top of the rotor (4) and the inner wall of the reaction chamber (6).

4. The rotary compression concentrated solar water splitting hydrogen production reactor according to claim 2, characterized in that: Each arc-shaped surface of the rotor (4) is provided with a groove, and cerium oxide is arranged in the groove.

5. The rotary compression concentrated solar water splitting hydrogen production reactor according to claim 1 or 4, characterized in that: The cerium oxide is made into a porous structure by pressing.

6. The rotary compression concentrated solar water splitting hydrogen production reactor according to claim 1, characterized in that: The front end cover (1) is provided with a sealing gear (3), which is sleeved on the shaft (5); the rotor (4) is provided with an internal gear, which is meshed with the sealing gear (3).

7. The rotary compression concentrated solar water splitting hydrogen production reactor according to claim 1 or 6, characterized in that: The rotors (4) of the plurality of rotary compression-type concentrated solar water splitting hydrogen production reactors connected in series on the shaft (5) are installed at different phases.

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