Conical ammonia decomposition reactor hydrogen production device for solar thermochemical energy storage

Abstract

The invention discloses a conical ammonia decomposition reactor hydrogen production device for solar thermochemical energy storage. The conical ammonia decomposition reactor hydrogen production device comprises a solar condenser, a reactor body and a supporting structure, the reactor body comprises a feeding main pipeline, a heat exchanger, an inlet manifold, a conical convergent reaction pipeline, a transfer pipeline, an outlet manifold and a discharging main pipeline; the conical convergent reaction pipeline is of a hollow conical structure and comprises a gas inlet end and a gas outlet end, and the caliber of the gas inlet end is larger than that of the gas outlet end to form a conical pipeline; and a catalyst is arranged in the conical convergent reaction pipeline. The conical ammonia decomposition reactor hydrogen production device for solar thermochemical energy storage gives full play to the advantages of solar energy through a specific structure, can efficiently receive and distribute heat energy transmitted by the solar condenser, and is high in photo-thermal conversion utilization rate and high in energy efficiency. The problems of local overheating and slow temperature rise of ammonia gas in a traditional cylindrical reactor are solved, and the ammonia decomposition efficiency and the energy utilization efficiency are improved by optimizing the flow rate and the pressure drop through a specific structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ammonia decomposition hydrogen production, in particular to a conical ammonia decomposition reactor hydrogen production device for solar thermochemical energy storage. BACKGROUND

[0002] Under the background of energy transformation and sustainable development, ammonia decomposition hydrogen production technology shows significant advantages. Ammonia, as a high energy density hydrogen carrier, has an energy density of 12.7 MJ / kg, which is more than 4 times that of compressed hydrogen. It can be liquefied at 8-10 bar at normal temperature or -33℃, which is convenient for storage and transportation. It can be transported by using the existing global ammonia transportation network to realize large-scale hydrogen energy transportation. The decomposition reaction product is only nitrogen and hydrogen, which has no greenhouse gas emission. The hydrogen produced by decomposition has high purity and can be directly applied to fuel cells, chemical synthesis and other fields, which is an ideal path to build a hydrogen energy economy.

[0003] Traditional hydrogen production methods, such as water electrolysis, although mature in technology, have high energy consumption and rely on a large amount of electricity supply. The combination of solar energy and ammonia decomposition technology can effectively avoid the drawbacks of traditional processes, achieve zero carbon emission in the ammonia decomposition process, reduce dependence on fossil energy, and solve the problem of hydrogen energy storage and transportation by taking advantage of the high energy density and easy liquefaction of ammonia. It can build a green energy cycle system of "solar energy-ammonia-hydrogen".

[0004] In addition, the traditional cylindrical ammonia decomposition reactor usually uses a jacket or built-in heat exchange tube for heating. In high temperature working conditions (ammonia decomposition requires 800-1000℃), there is a large temperature difference between the reactor wall and the internal material, which leads to insufficient reaction in the center area and easy local overheating in the edge area. Especially when dealing with high flow rate of ammonia raw materials, the heat cannot be quickly and uniformly transferred, resulting in a 10%-20% decrease in overall decomposition efficiency.

[0005] In addition, for the ammonia decomposition process combined with solar thermal energy, the cylindrical structure is difficult to efficiently receive and distribute the heat energy transmitted by the solar concentrator, and the light-thermal conversion utilization rate is low, which cannot fully utilize the advantages of solar energy. SUMMARY

[0006] In view of the shortcomings of the prior art, the present application provides a conical ammonia decomposition reactor hydrogen production device for solar thermochemical energy storage. The conical ammonia decomposition reactor hydrogen production device for solar thermochemical energy storage of the present application fully utilizes the advantages of solar energy through a specific structure, can efficiently receive and distribute the heat energy transmitted by the solar concentrator, has a high light-thermal conversion utilization rate, and solves the problems of local overheating and slow ammonia temperature rise in the traditional cylindrical reactor. Through specific structure optimization of flow rate and pressure drop, the ammonia decomposition efficiency and energy utilization efficiency are improved.

[0007] The technical scheme of the present application is:

[0008] The hydrogen production device for solar thermochemical energy storage of the conical ammonia decomposition reactor comprises a solar concentrator, a reactor body and a support structure; the reactor body is arranged on the support structure and comprises a feeding main pipeline, a heat exchanger, an inlet manifold, a conical converging reaction pipeline, a transfer pipeline, an outlet manifold and a discharging main pipeline; one end of the feeding main pipeline is connected with the inlet manifold through the heat exchanger, the other end of the inlet manifold is connected with the conical converging reaction pipeline, and the other end of the conical converging reaction pipeline is connected with the transfer pipeline; one end of the outlet manifold is connected with the transfer pipeline, and the other end of the outlet manifold is connected with the heat exchanger; the discharging main pipeline is connected with the heat exchanger; the conical converging reaction pipeline has a hollow conical structure and comprises an inlet end and an outlet end, the inlet end has a larger diameter than the outlet end, and the conical pipeline is formed; the conical converging reaction pipeline is provided with a catalyst; during operation, cold ammonia gas enters the heat exchanger from the feeding main pipeline and enters the conical converging reaction pipeline through the inlet manifold; the ammonia gas in the conical converging reaction pipeline reacts to generate high-temperature hydrogen gas and high-temperature nitrogen gas under the action of the solar concentrator; the high-temperature hydrogen gas and the high-temperature nitrogen gas enter the heat exchanger through the transfer pipeline and the outlet manifold in sequence, exchange heat with the cold ammonia gas of the feed, preheat the cold ammonia gas, and are discharged from the discharging main pipeline.

[0009] Compared with the prior art, in the hydrogen production device for solar thermochemical energy storage of the conical ammonia decomposition reactor, the conical converging reaction pipeline is arranged, the ammonia gas flows through the conical passage, is affected by the conical structure, and is vertically incident to the conical surface by the solar energy, so that the effective light receiving area is increased, the advantages of the solar energy are fully utilized, the light-heat conversion utilization rate is high, the problems of local overheating and slow ammonia gas heating in the traditional cylindrical reactor are solved, the reaction gas flow is guided to form a reasonable temperature gradient through the conical gradual expansion design, the ammonia decomposition heat absorption characteristics are matched, and the heat transfer from the light receiving area to the reaction area is promoted; at the same time, the change of the passage cross-sectional area optimizes the flow velocity distribution, avoids the flow dead zone, enables the ammonia gas to fully contact with the catalyst in the catalyst bed, and the conical cavity provides a gradual change space for catalyst filling, so that the catalyst bed density and thickness distribution can be flexibly adjusted according to the reaction process (rapid heating at the inlet side and stable reaction demand at the outlet side), the catalysis and heat utilization are synergized, the ammonia gas continuous decomposition is promoted, the high-temperature hydrogen gas and the high-temperature nitrogen gas generated in the reaction can exchange heat with the cold ammonia gas of the feed through the heat exchanger before entering the discharging main pipeline, the cold ammonia gas is preheated, and therefore the energy utilization efficiency is improved.

[0010] As an optimization, the hydrogen production device for solar thermochemical energy storage of the preceding conical ammonia decomposition reactor, the structure of the discharge main pipe inside the heat exchanger is in a vortex shape. With this structure, it is beneficial for the high-temperature hydrogen and high-temperature nitrogen generated by the reaction to fully exchange heat with the cold ammonia gas of the feedstock, preheating the cold ammonia gas, thereby further improving the energy utilization efficiency.

[0011] As an optimization, the hydrogen production device for solar thermochemical energy storage of the preceding conical ammonia decomposition reactor, the conical converging reaction pipe and the outlet manifold are both multiple, uniformly distributed in a circular manner along the heat exchanger. This structure can simultaneously perform multiple groups of ammonia decomposition reactions, thereby improving the hydrogen production efficiency of the entire device.

[0012] As an optimization, the hydrogen production device for solar thermochemical energy storage of the preceding conical ammonia decomposition reactor, the reactor body is provided with a cavity radiation shielding cover on the outside. With this structure, a closed insulation cavity is formed between the reactor body and the cavity radiation shielding cover, which can effectively reduce heat loss and improve heat utilization. Further, the cavity radiation shielding cover is coated with thermal insulation material. This structure further reduces heat loss.

[0013] As an optimization, the hydrogen production device for solar thermochemical energy storage of the preceding conical ammonia decomposition reactor, the support structure is provided with a mirror, which is in the form of a circular ring. This structure can reflect part of the unabsorbed solar radiation onto the conical converging reaction pipe, improving the efficiency of light and heat capture. Further, the mirror is a water-cooled mirror. This structure effectively improves the heat dissipation capacity of the mirror body through the water circulation pipe inside the mirror body, keeping the mirror body at the optimal working temperature.

[0014] As an optimization, the hydrogen production device for solar thermochemical energy storage of the preceding conical ammonia decomposition reactor, the length of the conical converging reaction pipe is 500-600 mm, the inlet diameter is 25-30 mm, the outlet diameter is 7.5-13 mm, and the taper angle is 2°-4.5°. This structure has better light receiving properties, higher system thermal efficiency, and higher hydrogen production capacity.

[0015] As an optimization, the hydrogen production device for solar thermochemical energy storage of the preceding conical ammonia decomposition reactor, the conical converging reaction pipe is made of chromium-nickel-iron alloy pipe. Chromium-nickel-iron alloy pipe has high temperature stability and can maintain high strength and creep resistance at high temperatures.

[0016] As an optimization, the hydrogen production device for solar thermochemical energy storage of the preceding conical ammonia decomposition reactor, the catalyst is an iron-based catalyst. Iron-based catalysts have lower costs, which can save a lot of expenses for enterprises, especially for large-scale industrial production. Further, the particle size of the iron-based catalyst is 0.4-0.6 mm. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the structural schematic diagram of the conical ammonia decomposition reactor hydrogen production device for solar thermochemical energy storage in the present application;

[0018] Figure 2 is Figure 1 the structural schematic diagram of the cavity radiation shield removed;

[0019] Figure 3 is the structural schematic diagram of the reactor body in the present application;

[0020] Figure 4 is Figure 3 the partial structural schematic diagram in the present application;

[0021] Figure 5 is Figure 4 the partial structural schematic diagram in the present application;

[0022] Figure 6 is Figure 5 the partial structural schematic diagram in the present application.

[0023] The marks in the drawings are: 1-solar concentrator; 2-reactor body, 21-feed main pipeline, 22-heat exchanger, 23-inlet manifold, 24-conical converging reaction pipeline, 25-transit pipeline, 26-outlet manifold, 27-discharge main pipeline; 3-supporting structure; 4-cavity radiation shield; 5-reflector. DETAILED DESCRIPTION

[0024] The present application will be further described below in combination with the drawings and examples, but it is not limited to the basis of the present application. In the following examples, the contents not described in detail or not shown in detail in the drawings are all the technical common sense in the art.

[0025] Example (see Figures 1-6 ):

[0026] The application discloses a hydrogen production device for solar thermochemical energy storage, which comprises a solar concentrator 1, a reactor body 2 and a supporting structure 3; the reactor body is arranged on the supporting structure 3 and comprises a feeding main pipeline 21, a heat exchanger 22, an inlet manifold 23, a conical converging reaction pipeline 24, a transfer pipeline 25, an outlet manifold 26 and a discharging main pipeline 27; one end of the feeding main pipeline 21 is connected with the inlet manifold 23 through the heat exchanger 22, the other end of the inlet manifold 23 is connected with the conical converging reaction pipeline 24, and the other end of the conical converging reaction pipeline 24 is connected with the transfer pipeline 25; one end of the outlet manifold 26 is connected with the transfer pipeline 25, and the other end of the outlet manifold 26 is connected with the heat exchanger 22; the discharging main pipeline 27 is connected with the heat exchanger 22; the conical converging reaction pipeline 24 is a hollow conical structure and comprises an air inlet end and an air outlet end, the air inlet end has a larger diameter than the air outlet end, and the conical converging reaction pipeline 24 forms a conical pipeline; the conical converging reaction pipeline 24 is provided with a catalyst.

[0027] In the embodiment, the structure of the discharging main pipeline 27 inside the heat exchanger 22 is vortex-shaped. The vortex-shaped structure is beneficial to the sufficient heat exchange between high-temperature hydrogen, high-temperature nitrogen generated in the reaction and cold ammonia, and the preheating of the cold ammonia, so that the energy utilization efficiency is further improved.

[0028] In the embodiment, the conical converging reaction pipeline 24 and the outlet manifold 26 are both multiple and are uniformly distributed in a circumferential shape along the heat exchanger 22. The structure can simultaneously perform multiple groups of ammonia decomposition reactions, so that the hydrogen production efficiency of the whole device is improved.

[0029] In the embodiment, the reactor body 2 is provided with a cavity radiation shielding cover 4, and the cavity radiation shielding cover 4 is coated with heat insulation materials. The structure can form a closed heat preservation cavity between the reactor body 2 and the cavity radiation shielding cover 4, so that the heat loss is effectively reduced and the heat utilization rate is improved.

[0030] In the embodiment, the supporting structure 3 is provided with a reflecting mirror 5, and the reflecting mirror 5 is in a circular ring shape. The structure can reflect part of the solar radiation which is not directly reflected to the conical converging reaction pipeline 24 to the conical converging reaction pipeline 24 through the reflecting mirror 5, so that the light and heat capturing efficiency is improved.

[0031] In the embodiment, the length of the conical converging reaction pipeline 24 is 500 mm, the pipeline inlet diameter is 25 mm, the pipeline outlet diameter is 7.5 mm, and the taper angle is 3.5°. The structure has better light receiving performance, higher system thermal efficiency and hydrogen production capacity.

[0032] In the embodiment, the conical converging reaction pipeline 24 is a chromium-nickel-iron alloy pipe. The chromium-nickel-iron alloy pipe has high temperature stability and can still maintain high strength and creep resistance at high temperature.

[0033] In this embodiment, the catalyst is an iron-based catalyst, and the particle size is 0.4-0.6 mm. The iron-based catalyst has a low cost, and can save a large amount of expenditure for enterprises, and is particularly suitable for large-scale industrial production.

[0034] When the hydrogen production device for solar thermochemical energy storage of this embodiment is working, the cold ammonia gas enters the heat exchanger 22 from the feed main pipeline 21, and enters the conical converging reaction pipeline 24 through the inlet manifold 23; the ammonia gas in the conical converging reaction pipeline 24 is reacted to generate high-temperature hydrogen gas and high-temperature nitrogen gas under the action of the solar concentrator 1; the high-temperature hydrogen gas and the high-temperature nitrogen gas enter the heat exchanger 22 through the transfer pipeline 25 and the outlet manifold 26 in sequence, exchange heat with the cold ammonia gas, preheat the cold ammonia gas, and are discharged from the discharge main pipeline 27.

[0035] In addition, the hydrogen production device for solar thermochemical energy storage of this embodiment can also be connected with an auxiliary heating source, which is used for auxiliary heating of the conical converging reaction pipeline 24. This design can perform auxiliary heating on the conical converging reaction pipeline 24 when the incident light flux is insufficient, so as to maintain the required reaction temperature.

[0036] The general description of the invention involved in the present application and the description of the specific embodiments thereof should not be understood as a limitation on the technical solutions of the invention. Based on the disclosure of the present application, those skilled in the art can add, reduce or combine the disclosed technical features in the general description or / and the specific embodiments (including the embodiments) without violating the elements of the invention involved, to form other technical solutions within the protection scope of the present application.

Claims

1. A hydrogen production device for solar thermochemical ammonia decomposition reactor, comprising a solar concentrator (1), a reactor body (2) and a support structure (3); the reactor body is arranged on the support structure (3) and comprises a feed main pipeline (21), a heat exchanger (22), an inlet manifold (23), a tapered converging reaction pipeline (24), a transfer pipeline (25), an outlet manifold (26) and a discharge main pipeline (27); one end of the feed main pipeline (21) is connected with the inlet manifold (23) through the heat exchanger (22), the other end of the inlet manifold (23) is connected with the tapered converging reaction pipeline (24), and the other end of the tapered converging reaction pipeline (24) is connected with the transfer pipeline (25); one end of the outlet manifold (26) is connected with the transfer pipeline (25), and the other end is connected with the heat exchanger (22); the discharge main pipeline (27) is connected with the heat exchanger (22); the tapered converging reaction pipeline (24) is a hollow tapered structure and comprises an inlet end and an outlet end, the inlet end has a larger diameter than the outlet end, forming a tapered pipeline; a catalyst is arranged in the tapered converging reaction pipeline (24). During operation, cold ammonia gas enters the heat exchanger (22) from the feed main pipeline (21), and enters the tapered converging reaction pipeline (24) through the inlet manifold (23); the ammonia gas in the tapered converging reaction pipeline (24) is reacted to generate high-temperature hydrogen and high-temperature nitrogen under the action of the solar concentrator (1); the high-temperature hydrogen and the high-temperature nitrogen enter the heat exchanger (22) through the transfer pipeline (25) and the outlet manifold (26) in sequence, exchange heat with the cold ammonia gas, preheat the cold ammonia gas, and are discharged from the discharge main pipeline (27).

2. The conical ammonia decomposition reactor hydrogen plant for solar thermo-chemical energy storage according to claim 1, characterized in that: The structure of the discharge main pipeline (27) inside the heat exchanger (22) is in a vortex shape.

3. The conical ammonia decomposition reactor hydrogen generator for solar thermo-chemical energy storage according to claim 2, characterized in that: The tapered converging reaction pipeline (24) and the outlet manifold (26) are both multiple and are uniformly distributed in a circumferential shape along the heat exchanger (22).

4. The conical ammonia decomposition reactor hydrogen generator for solar thermo-chemical energy storage according to claim 3, characterized in that: A cavity radiation shielding cover (4) is arranged on the outside of the reactor body (2).

5. The conical ammonia decomposition reactor hydrogen generator for solar thermo-chemical energy storage according to claim 4, characterized in that: A reflector (5) is arranged on the support structure (3), and the reflector (5) is in a circular ring shape.

6. The conical ammonia decomposition reactor hydrogen generator for solar thermo-chemical energy storage according to any one of claims 1-5, characterized in that: The length of the tapered converging reaction pipeline (24) is 500-600 mm, the inlet diameter of the pipeline is 25-30 mm, the outlet diameter is 7.5-13 mm, and the taper angle is 2°-4.5°.

7. The conical ammonia decomposition reactor hydrogen generator for solar thermo-chemical energy storage according to claim 6, characterized in that: The tapered converging reaction pipeline (24) is a chromium-nickel-iron alloy pipe.

8. The conical ammonia decomposition reactor hydrogen plant for solar thermo-chemical energy storage according to claim 7, characterized by: The catalyst is an iron-based catalyst.

9. The conical ammonia decomposition reactor hydrogen generator for solar thermo-chemical energy storage according to claim 8, characterized by: The particle size of the iron-based catalyst is 0.4-0.6 mm.

Images