A passive-active control combined thermal management type methane reforming reactor

Abstract

The application discloses a kind of methane reforming reactor of active and passive control combination heat management, including reactor shell and stepper motor, reactor shell and its upper end connected sapphire window are with the reaction cavity formed, reactor shell inside is filled with porous medium, and the side of reactor shell and shell bottom are provided with reaction gas inlet and reaction gas outlet respectively;Reactor shell outside is fixed with heat storage device shell, and phase change heat storage material is installed in closed cavity surrounded by reactor shell outside, heat storage device shell and sapphire window;Heat insulation layer is arranged around the outside of heat storage device shell;Stepper motor is used to drive reactor to approach or move away from solar radiation focus, to adjust heat input.The application stores excess heat by phase change heat storage material and compensates heat when temperature is low, and makes reactor surface energy flow tend to be stable by actively adjusting reactor to approach or move away from solar radiation focus, thereby solving the problem of unstable methane dry reforming reaction.

Description

Technical Field

[0001] This invention relates to methane reforming reactors, and more specifically to a thermally managed methane reforming reactor that combines active and passive control. Background Technology

[0002] Both CH4 and CO2 are greenhouse gases. Reforming CH4 and CO2 at high temperatures to produce CO and H2 can simultaneously eliminate both greenhouse gases. The reforming reaction equation is as follows:

[0003]

[0004] This reforming reaction process requires a large amount of energy.

[0005] Solar energy is a renewable, abundant, and clean green energy source, offering unparalleled advantages for driving CH4-CO2 reforming through solar thermal energy. However, solar radiation is highly intermittent and fluctuating due to various factors such as weather, cloud cover, and seasonal variations. This instability in solar radiation intensity directly leads to drastic temperature fluctuations in solar-driven methane reforming reactors, consequently affecting internal temperature control and reaction stability. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a thermally managed methane reforming reactor that combines active and passive control to solve the problem of instability in the dry methane reforming reaction caused by fluctuations in solar radiation.

[0007] Technical Solution: The present invention discloses a thermally managed methane reforming reactor with combined active and passive control, comprising a reactor shell and a stepper motor. A sapphire window for light to enter the reactor is connected to the upper end of the reactor shell. The sapphire window and the reactor shell form a reaction chamber. The reactor shell is filled with a porous medium. A reaction gas inlet is provided on one side of the reactor shell, and a reaction gas outlet is provided at the bottom of the reactor shell. A heat storage device shell is fixed to the outside of the reactor shell. A phase change heat storage material is installed in the closed cavity formed by the outside of the reactor shell, the heat storage device shell, and the sapphire window. An insulation layer is provided around the outside of the heat storage device shell. The stepper motor is used to drive the reactor closer to or further away from the solar radiation focal point to adjust the heat input.

[0008] Furthermore, the thermally managed methane reforming reactor also includes a gas-liquid separation device, with the reaction gas outlet connected to the gas-liquid separation device.

[0009] Furthermore, the thermally managed methane reforming reactor also includes a regenerator, which uses the high-temperature gas generated by the reaction to heat the reaction gas, and the heated reaction gas is input into the reactor from the reaction gas inlet.

[0010] Furthermore, the thermally managed methane reforming reactor also includes multiple thermocouples to monitor the surface temperature of the porous medium, the temperature of the phase change heat storage material, and the temperature of the reaction gas outlet gas, respectively.

[0011] Furthermore, the porous medium consists of a metal porous foam and a catalyst, wherein the metal porous foam is made by 3D printing copper, nickel and high-temperature alloys containing these two elements, and the catalyst is made of Ni, Co, Si, Cu, Al, Ag or Rh.

[0012] Furthermore, the phase change thermal storage material is one or more of carbonates, hydrochlorides, chlorides, lithium salts, and sulfates. When it is multiple, it is a eutectic salt composed of any components.

[0013] Furthermore, the reactor shell and the heat storage device shell are cylindrical and made of high-temperature resistant stainless steel.

[0014] Furthermore, once the porous medium reaches a certain temperature, the reaction gas is introduced through the reaction gas inlet;

[0015] Under stable solar radiation conditions, the reactor temperature and conversion rate are kept stable by adjusting the inlet reactant gas flow rate to vary with changes in solar radiation.

[0016] When the radiation intensity increases, the reactor is controlled to move away from the solar radiation focus by a stepper motor, while the flow rate of the reactant gas is increased; when the radiation intensity decreases, the reactor is controlled to move closer to the solar radiation focus by a stepper motor, while the flow rate of the reactant gas is reduced; thus ensuring the stable operation of the reactor.

[0017] Furthermore, when the direct normal radiation (DNI) is different, the distance between the reactor and the solar radiation focus and the incident energy satisfy different linear relationships.

[0018] Furthermore, when DNI is 900, y = -23x + 1900; when DNI is 600, y = -18x + 1500; when DNI is 300, y = -15x + 1200; x is the distance between the reactor and the solar radiation focus, and y is the incident energy.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0020] (1) Active thermal management: The reaction process is optimized by actively adjusting the distance between the reactor and the solar radiation focus and controlling the gas flow rate. Different distances on the concentrator axis correspond to different light intensities. By actively adjusting the reactor to be closer to or further away from the solar radiation focus, the energy flow on the reactor surface can be stabilized under different radiation intensities, ensuring that the reaction process can proceed efficiently and stably under various radiation conditions.

[0021] (2) Passive thermal management: Phase change thermal storage materials have the characteristics of high thermal density and small temperature change, and can absorb / release a large amount of heat during the phase change process. Using phase change thermal storage materials for thermal management of methane dry reforming reaction can improve the temperature stability of the reactor under radiation fluctuation conditions.

[0022] This invention combines active and passive thermal management to precisely control reactor temperature fluctuations, significantly improving reactor operational stability and thermal efficiency, and effectively solving the problem of drastic temperature fluctuations caused by solar radiation fluctuations during methane dry reforming. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the thermally managed methane reforming reactor provided in an embodiment of the present invention;

[0024] Figure 2 yes Figure 1 A schematic diagram of the main structure of the reactor.

[0025] Figure 3 This is a schematic diagram of the experimental system of the methane reforming reactor in an embodiment of the present invention;

[0026] Figure 4 This is a performance comparison chart of the present invention and a conventional reactor under radiation fluctuation conditions, in which... Figure 4 (a) is a comparison chart of methane conversion rates. Figure 4 (b) is a comparison chart of average foam temperatures;

[0027] Figure 5 This is a graph showing the relationship between light intensity and DNI at different distances in an embodiment of the present invention. Figure 5 (a) is a diagram showing the incident energy flow distribution under different powers. Figure 5 (b) is the incident energy flow fitting diagram. Figure 5 (c) is a graph showing the relationship between the distance between the reactor and the solar radiation focus and the incident energy at different power levels. Figure 5 (d) is the radial distribution of the incident energy flow. Detailed Implementation

[0028] The invention will now be further described with reference to the accompanying drawings.

[0029] Appendix Figures 1 to 5 The accompanying figure labels are as follows:

[0030] 1. Sapphire window; 2. Reactor gas inlet; 3. Phase change thermal storage material; 4. Thermal storage device shell; 5. Reactor shell; 6. Insulation layer; 7. Porous medium; 8. Reactor gas outlet; 9. Gas-liquid separation device; 10. Thermocouple; 11. Stepper motor; 12. Regenerator.

[0031] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a thermally managed methane reforming reactor that combines active and passive control, including a reactor shell 5, a gas-liquid separation device 9, a stepper motor 11, a regenerator 12, and three thermocouples 10.

[0032] The reactor shell 5 is cylindrical and made of high-temperature resistant stainless steel. A sapphire window 1 is connected to the upper end of the reactor shell 5 to allow focused light to enter the reactor. The sapphire window 1 and the reactor shell 5 form a reaction chamber, and the interior of the reactor shell 5 is filled with porous media 7. A reaction gas inlet 2 is located on the right side of the reactor shell 5, and a reaction gas outlet 8 is located at the bottom of the reactor shell 5.

[0033] A heat storage device shell 4 is fixed to the outside of the reactor shell 5. This heat storage device shell 4 is also cylindrical and made of high-temperature resistant stainless steel. A phase change heat storage material 3 is installed within the closed cavity formed by the outside of the reactor shell 5, the heat storage device shell 4, and the sapphire window 1. The phase change heat storage material 3 can store and release heat. An insulation layer 6 is provided around the outside of the heat storage device shell 4, which effectively reduces heat loss.

[0034] The reaction gas outlet 8 is rigidly connected to the gas-liquid separator 9 via a PTFE tube. The gas-liquid separator 9 is fixed at the front end of the regenerator 12. The gas-liquid separator 9 uses absorbent silica gel to absorb the water produced in the reaction, thereby separating the gaseous and liquid phase products. The high-temperature gas produced in the reaction exchanges heat with the reaction gas in the regenerator 12. The heated reaction gas is then input into the reactor through the reaction gas inlet 2, improving the overall thermal efficiency of the reactor.

[0035] A stepper motor 11 is fixed to the front support plate of the reactor shell 5. The stepper motor 11 is used to drive the reactor closer to or further away from the solar radiation focus to adjust the heat input. Three thermocouples 10 monitor the surface temperature of the porous medium 7, the temperature of the phase change heat storage material 3, and the gas temperature at the reaction gas outlet 8, respectively.

[0036] The porous medium 7 consists of a metal porous foam and a catalyst. The metal porous foam is 3D printed from copper, nickel, or high-temperature alloys containing these two elements. The catalyst is made of Ni, Co, Si, Cu, Al, Ag, or Rh. In this embodiment, the metal porous foam has a length L = 0.03 m, a porosity Φ = 0.8, a pore diameter d = 2.5 mm, and an indentation depth h = 12 mm.

[0037] The phase change thermal storage material 3 is one or more of carbonates, hydrochlorides, chlorides, lithium salts, and sulfates. When it is multiple, it is a eutectic salt composed of any components.

[0038] The methane reforming reactor described in the embodiments of the present invention is connected to... Figure 3The experimental system shown (which is an existing system) does not introduce reaction gas in the early stage of the reaction. Solar radiation passes through the sapphire window 1, the temperature of the porous medium 7 rises, and the phase change thermal storage material 3 is heated through radial heat transfer. The phase change thermal storage material 3 absorbs heat and rises in temperature. Part of the phase change thermal storage material 3 undergoes a phase change process and stores energy in the form of latent heat.

[0039] After the porous medium 7 reaches a certain temperature, the reaction gas is introduced through the reaction gas inlet 2.

[0040] Radiation intensity is obtained in real time through DNI monitoring equipment. Under stable solar radiation conditions, the inlet reactive gas flow rate is adjusted (the gas flow rate is determined by...). Figure 3 The control box shown (which contains a built-in flow meter) adjusts according to changes in solar radiation to maintain stable reactor temperature and conversion rate.

[0041] When the radiation intensity increases, the reactor is controlled to move away from the solar radiation focus by stepper motor 11, while the flow rate of the reactant gas is increased to maintain the stable operation of the reactor.

[0042] When the radiation intensity decreases, the stepper motor 11 controls the reactor to move closer to the solar radiation focus, while reducing the flow rate of the reactant gas to ensure the stable operation of the reactor.

[0043] The distance between the reactor and the solar radiation focus must be adjusted to meet the following requirements. Figure 5 The empirical formula shown in (c) ensures that the reactor surface energy is maintained at a stable level of approximately 350 W. When the direct normal intensity (DNI) is 900, the relationship between energy and axial distance is y = -23x + 1900; when the DNI is 600, the relationship is y = -18x + 1500; and when the DNI is 300, the relationship is y = -15x + 1200. x represents the axial distance (the distance between the reactor front surface and the xenon lamp, i.e., the distance between the reactor and the solar radiation focus), and y represents the incident energy. Under different DNI conditions, by adjusting the distance between the reactor and the solar radiation focus, the surface energy is kept within a stable range, thereby ensuring the stable operation of the reforming reactor.

[0044] Figure 4 The study demonstrates the variation of methane conversion rate over time under typical radiation fluctuations. The results show that without thermal storage, the methane conversion rate fluctuates significantly. Specifically, without thermal storage, the methane conversion rate fluctuates between 55.43% and 61.39%, with an average conversion rate of 58.5%. In contrast, the reactor designed in this invention exhibits a methane conversion rate fluctuation range of 58.79% to 62.23%, representing a reduction of 2.52% in fluctuation range and an increase in average conversion rate of 2 percentage points.

[0045] In summary, this invention combines passive thermal management of heat storage and release with active thermal management of the distance to the solar radiation focal point, which can significantly improve the efficiency and stability of solar thermal chemical fuel production.

Claims

1. A thermally managed methane reforming reactor combining active and passive control, characterized in that, The reactor includes a reactor shell (5) and a stepper motor (11). The upper end of the reactor shell (5) is connected to a sapphire window (1) for light to enter the reactor. The sapphire window (1) and the reactor shell (5) form a reaction chamber. The reactor shell (5) is filled with a porous medium (7). A reaction gas inlet (2) is provided on one side of the reactor shell (5), and a reaction gas outlet (8) is provided at the bottom of the reactor shell (5). A heat storage device shell (4) is fixed on the outside of the reactor shell (5). A phase change heat storage material (3) is installed in the closed cavity formed by the outside of the reactor shell (5), the heat storage device shell (4), and the sapphire window (1). An insulation layer (6) is provided on the outside of the heat storage device shell (4). The stepper motor (11) is used to drive the reactor closer to or further away from the solar radiation focus to adjust the heat input. After the porous medium (7) reaches a certain temperature, the reaction gas is introduced from the reaction gas inlet (2); Under stable solar radiation conditions, the reactor temperature and conversion rate are kept stable by adjusting the inlet reactant gas flow rate to vary with changes in solar radiation. When the radiation intensity increases, the reactor is controlled to move away from the solar radiation focus by stepper motor (11) while the flow rate of the reactant gas is increased; when the radiation intensity decreases, the reactor is controlled to move closer to the solar radiation focus by stepper motor (11) while the flow rate of the reactant gas is reduced; thus ensuring the stable operation of the reactor. With different direct normal radiation (DNI), the distance between the reactor and the solar radiation focus and the incident energy satisfy different linear relationships; when the DNI is 900, ; When DNI is 600 When DNI is 300, ; The distance between the reactor and the solar radiation focus. The incident energy.

2. The thermally managed methane reforming reactor according to claim 1, characterized in that, It also includes a gas-liquid separation device (9), and the reaction gas outlet (8) is connected to the gas-liquid separation device (9).

3. The thermally managed methane reforming reactor according to claim 2, characterized in that, It also includes a regenerator (12), which uses the high-temperature gas generated by the reaction to heat the reaction gas. The heated reaction gas is then fed into the reactor from the reaction gas inlet (2).

4. The thermally managed methane reforming reactor according to claim 1, characterized in that, It also includes multiple thermocouples (10) to monitor the surface temperature of the porous medium (7), the temperature of the phase change thermal storage material (3), and the gas temperature at the outlet (8) of the reaction gas, respectively.

5. The thermally managed methane reforming reactor according to claim 1, characterized in that, The porous medium (7) is composed of a metal porous foam and a catalyst, wherein the metal porous foam is made of copper, nickel and high-temperature alloys containing these two elements by 3D printing, and the catalyst is made of Ni, Co, Si, Cu, Al, Ag or Rh.

6. The thermally managed methane reforming reactor according to claim 1, characterized in that, The phase change thermal storage material (3) is one or more of carbonates, hydrochlorides, chlorides, lithium salts, and sulfates. When it is multiple, it is a eutectic salt composed of any components.

7. The thermally managed methane reforming reactor according to claim 1, characterized in that, The reactor shell (5) and the heat storage device shell (4) are cylindrical and made of high-temperature resistant stainless steel.

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