Efficient heat exchange multi-tube thermochemical circulation hydrogen production device

Abstract

The invention provides an efficient heat exchange multi-tube thermochemical circulation hydrogen production device. The device comprises a device lower section, a device middle section and a device upper section which are connected in sequence, a heat exchange tube is arranged in the device lower section, a reaction gas inlet is formed in the bottom of the device lower section, and a flue gas outlet is formed in the side surface of the device lower section; a filling cavity is formed in the device middle section, a porous sieve plate is arranged in the filling cavity, a first refractory ball filling layer and a second refractory ball filling layer are arranged above the porous sieve plate, and a filling opening communicated to the filling cavity is formed in the side face of the device middle section; a plurality of reaction tubes are arranged in the device upper section and filled with catalysts, outer annular baffle plates and inner annular baffle plates are alternately arranged between the reaction tubes up and down, the heat exchange tubes and the reaction tubes are communicated to the filling cavity of the device middle section, a flue gas inlet and a reaction gas inlet are formed in the side face of the device upper section, and third refractory ball filling layers are arranged on the upper portions of the reaction tubes. The device can improve the heat exchange efficiency and reduce the reaction temperature at the same time.

Description

Technical Field

[0001] This invention belongs to the technical field, specifically relating to a high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device. Background Technology

[0002] Against the backdrop of energy transition, hydrogen energy, as a clean and efficient energy carrier, has received widespread global attention. Thermochemical cycle water splitting for hydrogen production has been extensively studied due to its high efficiency and stable hydrogen production capabilities. However, because water has relatively stable thermodynamic properties, thermochemical cycle water splitting for hydrogen production typically requires high temperatures (above 1500℃). In this process, thermochemical cycle water splitting for hydrogen production devices often have limited design considerations for heat exchange performance, and the heat exchange channels are overly simple. This leads to significant waste of heat resources and energy as heat is transferred to the air through heat transfer, radiation, and convection. Therefore, it is necessary to improve the thermochemical cycle water splitting for hydrogen production devices and the reaction process. Currently, research on such devices is relatively limited and not yet mature; therefore, developing novel devices is of great significance for the efficient production of hydrogen. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-tube thermochemical cycle hydrogen production device with high-efficiency heat exchange, which can improve heat exchange efficiency while reducing reaction temperature.

[0004] This invention provides the following technical solution:

[0005] This invention provides a high-efficiency heat-exchange multi-tube thermochemical cycle hydrogen production device, the device comprising a lower section, a middle section and an upper section connected in sequence;

[0006] The lower section of the device is equipped with a heat exchange tube, the bottom of the lower section of the device is equipped with a reaction gas inlet, and the side of the lower section of the device is equipped with a flue gas outlet.

[0007] The device has a filling cavity in the middle section, a porous sieve plate in the filling cavity, a first refractory ball filling layer and a second refractory ball filling layer above the porous sieve plate, and a filling port communicating with the filling cavity is opened on the side of the middle section of the device.

[0008] The upper section of the device is equipped with multiple reaction tubes, which are filled with catalyst. The reaction tubes are alternately equipped with outer and inner annular baffles. The heat exchange tubes and the reaction tubes are connected to the filling cavity in the middle section of the device. The upper section of the device is equipped with a flue gas inlet and a reaction gas inlet on its side. The upper part of the reaction tubes is equipped with a third refractory ball filling layer.

[0009] In this device, multiple layers of baffles are installed between the heat exchange tubes in the lower section to increase the contact area between the high-temperature flue gas and the reactant gas, thereby rapidly raising the temperature of the reactant gas to the reaction temperature for subsequent reaction in the reaction tubes. A filling cavity is set in the middle section of the device, with a porous sieve plate at the bottom to support the first and second refractory ball layers. The refractory balls can disperse the reactant gas, allowing it to be blown in evenly and improving the reaction efficiency. In the upper section of the device, inner and outer annular baffles are used alternately between the reaction tubes to maximize the heat exchange efficiency between the high-temperature flue gas and the reaction tubes, utilizing the reaction to proceed.

[0010] In this device, the catalyst can be an oxygen carrier (metal oxide). During the reaction, at 800℃, the metal-oxygen bond of the oxygen carrier breaks, releasing oxygen to react with the reaction gas (CH4 or flue gas), increasing the temperature inside the reaction tube. This stage is the fuel reaction stage. Then, the reaction gas is switched to water vapor, and the metal that has lost oxygen takes oxygen from H2O, releasing H2. At the same time, the oxygen carrier lowers the energy barrier for water splitting, accelerating the reaction process and thus significantly reducing the reaction temperature.

[0011] The third refractory ball filling layer can further capture the catalyst that is blown away by the reactive gas, preventing it from flying out.

[0012] Furthermore, the refractory balls packed in the first and second refractory ball packing layers have different particle sizes, with the particle size of the refractory balls in the first refractory packing layer being larger than that in the second refractory packing layer. The different particle sizes of the refractory balls can, to some extent, prevent the catalyst from being swept away due to excessive reactive gas flow rates.

[0013] Furthermore, a heat-insulating plug is provided at the top of the reaction tube.

[0014] Furthermore, an expansion joint is provided in the middle of the lower section of the device.

[0015] Furthermore, an ear seat is provided on the outer surface of the middle part of the upper section of the device.

[0016] Furthermore, a pressure grid is provided inside the reaction tube to fix the third refractory ball filling layer.

[0017] Furthermore, the upper end of the heat insulation plug is provided with a thermometer interface.

[0018] The present invention has the following beneficial effects:

[0019] 1. This invention employs a multi-tube reaction system with added baffles to increase heat exchange efficiency. Multiple reaction tubes are filled with a catalyst, which serves as an oxygen carrier. During the reaction, the metal-oxygen bonds of the oxygen carrier break, releasing oxygen (O) to react with the reaction gas (CH4 or flue gas), increasing the temperature inside the reaction tube. After the reaction gas is switched to water vapor, the metal that has lost oxygen (O) takes oxygen from H2O, releasing H2. The oxygen carrier also lowers the energy barrier for water splitting, accelerating the reaction process and significantly reducing the reaction temperature.

[0020] 2. The present invention is provided with a multi-layer refractory ball filling layer. The first and second refractory filling layers can disperse the reaction gas, so that the reaction gas is blown in evenly, improve the reaction efficiency, and make it fully contact the catalyst. The third refractory filling layer can capture the catalyst to prevent the catalyst from flying out with the gas. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a high-efficiency heat-exchange multi-tube thermochemical cycle hydrogen production device in one embodiment of the present invention;

[0023] Figure 2 for Figure 1 Sectional view of AA;

[0024] Figure 3 for Figure 1 Sectional view of BB;

[0025] Figure 4 The diagram shows a comparison between the multi-tube thermochemical cycle hydrogen production device and the single-tube device of the present invention, wherein (a) is the single-tube device and (b) is the multi-tube thermochemical cycle hydrogen production device of the present invention.

[0026] Figure 5 This is a comparison diagram of the heat exchange effect and temperature distribution of each device under operating conditions 1 and 2 of the present invention.

[0027] Figure 6 This is a comparison diagram showing the influence of heat exchange effect and temperature distribution of each device under operating conditions 2 and 3 of the present invention.

[0028] Figure 7 This is a comparison diagram of the heat exchange effect and temperature distribution of each device under operating conditions 2 and 4 of the present invention.

[0029] Figure 8 This is a comparison diagram showing the influence of heat exchange effect and temperature distribution of each device under operating conditions 2 and 5 of the present invention.

[0030] In the diagram: 1-Lower section of the device; 2-Heat exchange tube; 3-Baffle plate; 4-Expansion joint; 5-Filling port; 6-Pressure grid; 7-Upper section of the device; 8-Reaction gas discharge section; 9-Insulation plug; 10-Ear seat; 11-Third refractory ball filling layer; 12-Upper tube sheet; 13-Reaction tube; 14-Inner annular baffle plate; 15-Outer annular baffle plate; 16-Catalyst; 17-Second refractory ball filling layer; 18-Middle section of the device; 19-First refractory ball filling layer; 20-Porous sieve plate; 21-Reaction gas inlet; 22-Flue gas inlet; 23-Reaction gas outlet; 24-Flue gas outlet; 25-Thermometer interface. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] See Figures 1-3 This invention provides a high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device, which includes a lower section 1, a middle section 18, and an upper section 7 connected in sequence. The lower section 1 is equipped with heat exchange tubes 2, a reaction gas inlet 21 at the bottom of the lower section 1, and a flue gas outlet 24 on the side of the lower section 1. The middle section 18 is equipped with a filling cavity, in which a porous sieve plate 20 is provided. A first refractory ball filling layer 19 and a second refractory ball filling layer 17 are provided above the porous sieve plate 20. A filling port 5 communicating with the filling cavity is opened on the side of the middle section 18. The upper section 7 is equipped with multiple reaction tubes 13, which are filled with catalyst 16. An outer annular baffle 15 and an inner annular baffle 14 are alternately arranged between the reaction tubes 13. The heat exchange tubes 2 and the reaction tubes 13 are all connected to the filling cavity of the middle section. A flue gas inlet 22 and a reaction gas outlet 23 are provided on the side of the upper section 7. A third refractory ball filling layer 11 is provided on the upper part of the reaction tubes 13.

[0033] The device has a layered structure, and the reaction gas and flue gas do not interfere with each other. The reaction gas enters the heat exchange tube 2, the filling cavity and the reaction tube 13 in sequence through the reaction gas inlet 23 and then flows out through the reaction gas outlet 23. The flue gas enters from the flue gas inlet 22 and passes through the upper section 7, the middle section 18 and the lower section 1 of the device in sequence before being discharged from the flue gas outlet 24. The flue gas only flows within the layered structure outside the heat exchange tube 2, the filling cavity and the reaction tube 13, and exchanges heat with the reaction gas inside the heat exchange tube 2, the filling cavity and the reaction tube 13.

[0034] In this invention, the lower section 1 of the device is equipped with 61 heat exchange tubes 2 and alternating baffles 3. The baffles 3 increase the flow velocity of the fluid outside the tubes, forcing the fluid to flow through multiple bends along a predetermined path, thereby improving the heat transfer effect. An expansion joint 4 is provided in the middle of the lower section 1 to prevent thermal expansion from causing cracks in the lower part of the device. The heat exchange tubes 2 in the top of the lower section 1 are directly connected to the middle section of the device.

[0035] The middle section 18 of the device can be directly connected to the outside and is used to fill refractory balls. After filling is completed, the filling port 5 must be closed. It contains two different sizes of refractory balls. The lower part of the refractory balls is a porous sieve plate to support the refractory balls.

[0036] The upper section 7 of the device contains seven reaction tubes 13, each filled with a catalyst 16. Inner annular baffles 14 and outer annular baffles 15 are alternately arranged between each reaction tube 13. The reaction tubes 13 of the upper section 7 are connected to the middle section 18 of the device.

[0037] The reaction tube 13 is equipped with a pressure grid 6 to fix the third refractory ball filling layer 11. The upper part of the reaction tube 13 (the upper part of the third refractory ball filling layer 11) is the reaction gas discharge section 8, which is provided with space to ensure the discharge of reaction gas. The top of the reaction tube 13 is equipped with a heat insulation plug 9, and the upper end of the heat insulation plug 9 is equipped with a thermometer interface 25 for convenient temperature monitoring.

[0038] The upper section 7 of the device has an ear seat 6 on its outer surface in the middle. The ear seat 6 is designed to facilitate the installation of the entire device later.

[0039] During operation, the reaction gas enters through port N1, passes through heat exchange tube 2, porous sieve plate 22, and reaction tube, and finally exits the device through port N2. Due to the layered structure of this device, the high-temperature flue gas generated from biomass solid waste enters the device layer through port N3 before exiting through heat exchange tube 2 and reaction tube, and is then discharged through port N4.

[0040] This invention improves the single-tube reaction tube into a multi-tube reaction tube and adds baffles to increase heat exchange efficiency. Catalysts, which can be oxygen carriers, are filled into multiple reaction tubes. During the reaction, at 800°C, the metal-oxygen bonds of the oxygen carrier break, releasing oxygen to react with the reaction gas (CH4 or flue gas) (this is the fuel reaction stage). Then, the reaction gas is switched to water vapor, and the metal that has lost oxygen takes oxygen from H2O, releasing H2. Simultaneously, the oxygen carrier lowers the energy barrier for water splitting, accelerating the reaction process and thus significantly reducing the reaction temperature.

[0041] The following comparison is made between the device provided in this embodiment and the single-tube device, and data monitoring is performed on the device under different operating conditions, as detailed below:

[0042] Compared to this device and the single-tube device, the single-tube device is as follows: Figure 4 As shown in (a), there is only one reaction tube with a diameter of 325 mm; multi-tube devices are as follows: Figure 4 As shown in (b), there are six reaction tubes with a diameter of 90 mm. Other major geometric dimensions of the unit are as follows: inlet and outlet diameters of the reactant gas and flue gas are 159 mm; the heat exchange tubes are 550 mm long and 50 mm in diameter; and the total height of the unit is 3000 mm. The catalyst is an oxygen carrier (CoNiCuMgCa)Fe2O4. The boundary condition parameters for each operating condition are detailed in Table 1.

[0043] Table 1. Influence of device structure on heat exchange efficiency and temperature distribution under various parameter conditions.

[0044]

[0045]

[0046] Comparing operating conditions 1 and 2, see [reference] Figure 5 When the high-temperature flue gas inlet temperature was 1273K, the average outlet temperatures of the high-temperature flue gas in the single-tube and multi-tube units were 854K and 865K, respectively, while the outlet temperatures of the pyrolysis gas were 892K and 919K, respectively. The inner diameter of the single-tube unit was 325mm, significantly larger than that of the multi-tube unit (90mm), resulting in a smaller effective heat exchange area and poorer heat exchange performance. Notably, the temperature of the core region of the metal oxide inside the multi-tube unit (870K) was significantly higher than that of the single-tube unit (833K).

[0047] Comparing operating conditions 2 and 3, see [reference]. Figure 6 Increasing the flue gas flow rate shows a significant improvement in temperature compared to the single-tube unit. When the high-temperature flue gas flow rate increases fivefold, the high-temperature flue gas outlet temperature rises significantly from 865K to 1049K. The reactant gas outlet temperature also increases from 919K to 1142K.

[0048] Comparing operating conditions 2 and 4, see [reference] Figure 7 In addition to increasing the flow rate of high-temperature flue gas, the temperature of metal oxides can also be increased by raising the temperature of high-temperature flue gas: when the inlet temperature of high-temperature flue gas increases by 200K, the outlet temperature of high-temperature flue gas and the outlet temperature of reactant gas increase by 44K and 57K respectively, and the core temperature of metal oxides is 925K. Compared with single-tube devices, the overall temperature of multi-tube devices is improved to a certain extent.

[0049] Comparing operating conditions 2 and 5, see [reference]. Figure 8Simultaneously, the inlet temperature and flow rate of the high-temperature flue gas were increased: the outlet temperature of the high-temperature flue gas rose from 865K to 1103K, and the outlet temperature of the reactant gas increased from 919K to 1272K. Notably, the temperature in the metal oxide core region also increased from 870K to 1070K. It can be seen that by simultaneously increasing the inlet temperature and flow rate of the high-temperature flue gas, the overall temperature of the multi-tube unit was significantly improved, far exceeding that of the single-tube unit.

[0050] The above analysis shows that this device has higher heat exchange efficiency and lower reaction temperature compared to a single-tube device. The effect of the device can be further improved by increasing the inlet temperature of the high-temperature flue gas and the flue gas flow rate.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device, characterized in that, The device comprises a lower section, a middle section, and an upper section connected in sequence. The lower section of the device is equipped with a heat exchange tube, the bottom of the lower section of the device is equipped with a reaction gas inlet, and the side of the lower section of the device is equipped with a flue gas outlet. The device has a filling cavity in the middle section, a porous sieve plate in the filling cavity, a first refractory ball filling layer and a second refractory ball filling layer above the porous sieve plate, and a filling port communicating with the filling cavity is opened on the side of the middle section of the device. The upper section of the device is equipped with multiple reaction tubes, which are filled with catalyst. The reaction tubes are alternately equipped with outer and inner annular baffles. The heat exchange tubes and the reaction tubes are connected to the filling cavity in the middle section of the device. The upper section of the device is equipped with a flue gas inlet and a reaction gas inlet on its side. The upper part of the reaction tubes is equipped with a third refractory ball filling layer.

2. The high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device as described in claim 1, characterized in that: The refractory balls filled in the first and second refractory ball filling layers have different particle sizes, with the particle size of the refractory balls in the first refractory filling layer being larger than that in the second refractory filling layer.

3. The high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device as described in claim 1, characterized in that: The top of the reaction tube is equipped with a heat insulation plug.

4. The high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device as described in claim 1, characterized in that: An expansion joint is provided in the middle of the lower section of the device.

5. The high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device as described in claim 1, characterized in that: The upper section of the device has an ear seat on its outer surface in the middle.

6. The high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device as described in claim 1, characterized in that: The reaction tube is equipped with a pressure grid to fix the third refractory ball filling layer.

7. The high-efficiency heat exchange multi-tube thermochemical cycle hydrogen production device as described in claim 3, characterized in that: The upper end of the heat insulation plug is equipped with a thermometer interface.

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