Solar dual-reforming reactor with three-stage backflow diversion control

Abstract

The invention discloses a solar dual-reforming reactor with three-stage backflow diversion control, and relates to a methane reforming reactor. The heat exchange process in the reactor is enhanced, the high-temperature heat of the reaction gas is utilized to preheat the fed raw material gas, and the utilization rate of the high-temperature heat in the reaction gas is increased. According to the technical scheme, the device comprises a reactor and a heat insulation layer wrapping the reactor, one end of the reactor is a solar radiation energy flow receiving end, and the other end of the reactor is a gas inlet and outlet end; a cylindrical flow guide plate is further embedded in the reactor, the axial length of the flow guide plate is smaller than that of the reactor, the flow guide plate extends to the gas inlet and outlet end, a reaction gas outlet is formed in the inner side of the flow guide plate, a roundabout flow guide structure embedded in the reactor is arranged between the flow guide plate and the heat insulation layer, and a raw material gas inlet is formed in the tail end of the roundabout flow guide structure. The flow of fluid in the reactor is changed by adding three-stage backflow diversion control, and the heat exchange process in the reactor is enhanced.

Description

Technical Field

[0001] The invention relates to a methane reforming reactor, in particular to a solar-driven methane double reforming reactor. Background Art

[0002] Currently, toward the strategic goal of carbon neutrality, solar thermochemical energy storage and fuel preparation technologies are key pathways for achieving energy transition and greenhouse gas emissions reduction. Among these, the solar-driven methane dual-processing reaction (CH4 + CO2 + H2O → H2 + CO) can synergistically utilize concentrated solar energy to efficiently convert greenhouse gases (CH4 / CO2) into high-value-added syngas (H2 / CO), offering the dual benefits of carbon reduction and clean fuel production, and possessing significant strategic significance. However, this highly endothermic reaction requires high temperatures and consumes significant energy. Currently, most widely used solar dual-processing reactors utilize a single-pass, unidirectional flow design (e.g., tubular or cavity reactors). Their inherent architecture results in the high-temperature syngas retaining a significant amount of sensible heat (above the reaction activation temperature) after the reaction. This heat is directly discharged without effective recovery, resulting in a waste of high-quality thermal energy and, to a certain extent, limiting the overall solar-to-chemical energy conversion efficiency of the system. Therefore, it is urgent to develop novel reactor structures to improve system efficiency and effectively recover and reuse the sensible heat of the high-temperature products within the reactor, thereby significantly improving process energy efficiency and economic benefits. Summary of the Invention

[0003] In response to the above problems, the present invention proposes a solar double-whole reactor with three-stage reflux diversion control, which strengthens the heat exchange process inside the reactor, uses the high-temperature heat of the reaction gas to preheat the incoming raw gas, and improves the utilization rate of the high-temperature heat in the reaction gas.

[0004] The technical solution of the present invention is as follows: comprising a reactor 1 and a heat-insulating layer 3 wrapped around the outside of the reactor 1, wherein one end of the reactor 1 is a solar radiation energy flow receiving end 2, and the other end is a gas inlet and outlet end; The reactor 1 is also embedded with a cylindrical guide plate 4, the axial length of the guide plate 4 is smaller than that of the reactor 1, and extends to the gas inlet and outlet ends. The inner side of the guide plate 4 is the reaction gas outlet 9, and a circuitous guide structure embedded in the reactor is provided between the guide plate 4 and the insulation layer 3, and the end of the circuitous guide structure is the raw gas inlet 8.

[0005] Furthermore, the circuitous guide structure includes a reflux baffle fixedly connected to the inner wall of the insulation layer 3 and a spacer plug fixedly connected to the outer wall of the guide plate 4. The reflux baffle and the spacer plug are both annular and are arranged alternately at equal intervals. There is a gap between the inner wall of the reflux baffle and the outer wall of the guide plate 4, and between the outer wall of the spacer plug and the inner wall of the insulation layer 3, thereby forming a circuitous raw gas entry channel between the guide plate 4 and the insulation layer 3.

[0006] Furthermore, there are three reflux baffles, which are the first-level reflux baffle 7, the second-level reflux baffle 6 and the third-level reflux baffle 5 from the outside to the inside, and the inner diameters of the three reflux baffles increase successively; the guide plate 4 is in a stepped cylindrical shape that gradually increases from the outside to the inside.

[0007] About reactor material selection: The internal structure of the reactor 1 is a porous medium structure, the porosity of the porous medium is 0.93, and the average pore diameter is 2 mm.

[0008] The porous medium structure is mainly composed of copper, nickel and high-temperature alloys containing these two elements.

[0009] The reactor further comprises an inner catalyst coated on the porous medium structure, wherein the catalyst is a catalyst having Ni, Co, Si, Cu, Al, Ag or Rh as a matrix.

[0010] Regarding the dimensions of the reactor and its internal baffles: The reactor 1 has a cylindrical shape and a cylindrical diameter. D =2 cm, cylinder height H =2 cm.

[0011] The thickness of the guide baffle 4, the spacer insert and the return baffle are d c = 0.25 mm; the height of the guide baffle 4 above the solar radiation energy flow receiving end 2 h =2 mm, the cross-sectional lengths of the primary reflux baffle 7, the secondary reflux baffle 6 and the tertiary reflux baffle 5 are respectively d 3=8 mm, d 2=6 mm, d 1=4 mm, the size of the raw gas inlet 8 and the circuitous raw gas inlet channel are both d in =2 mm, the distance between the guide plate 4 and the insulation layer 3 after the raw gas enters the channel d 0=2 mm.

[0012] In the present invention, a mixture of methane, carbon dioxide, and water vapor enters the reactor from the mixed gas inlet at the rear edge and reacts in the pores as it passes through the porous medium structure. The relatively cold raw gas introduced into the porous medium structure can first be heated by the higher-temperature porous medium and each partition in the three-layer reflux, and then guided by the guide plate into the radiation receiving end to be further heated. This enhances the heat exchange within the reactor, forming a reactor design that integrates preheating of the raw gas and reforming reaction, improves the utilization rate of the waste heat of the high-temperature generated gas, increases the overall temperature of the fluid in the reactor, and is more conducive to system energy transfer and thermochemical conversion.

[0013] In general, the present invention can be used for the dual reforming reaction process in solar dish concentrators. The reactor comprises a porous medium and a circuitous flow-guiding structure, with reactant gases flowing in from the rear edge and product gases flowing out from the rear center. The circuitous flow-guiding structure, composed of multiple layers of reflux baffles and guide plates, guides the reactant gases through the reactor's internal pores for reaction. The reactor exhibits a high specific surface area and excellent heat and mass transfer properties. By adding the circuitous flow-guiding structure within the porous medium structure (porous foam), the overall temperature of the fluid within the reactor is effectively increased and the high-temperature region is significantly expanded, thereby accelerating the reforming reaction rate, improving the reactant gas conversion rate, and enhancing system efficiency. By incorporating the circuitous flow-guiding structure, the present invention modifies the fluid flow within the reactor, enhancing the heat exchange process within the reactor. Compared to conventional unidirectional flow reactors, the present invention achieves an improvement in solar-to-chemical energy conversion efficiency of over 5.2% under conditions of an incident light intensity of 130.8 W and varying inlet flow rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an axial half-section view of the present invention; wherein 1 is a reactor, 2 is a solar radiation energy flow receiving end, 3 is a heat insulation layer, 4 is a guide plate, 5 is a tertiary reflux baffle, 6 is a secondary reflux baffle, 7 is a primary reflux baffle, 8 is a raw gas inlet, and 9 is a reaction gas outlet.

[0015] Figure 2 10 is the external structure diagram of the present invention; 10 is the synthesis gas outlet pipe, and 11 is the raw gas inlet pipe.

[0016] Figure 3 This is the dimension marking diagram of the three-stage reflux baffle.

[0017] Figure 4 、 5 These are performance comparison diagrams of the present invention and the traditional reactor at different inlet flow rates; Figure 4 The figure shows the comparison of average fluid temperature. The upper part shows the result of the present invention, and the lower part shows the result of the traditional configuration. Figure 5 This is a comparison chart of material conversion rate and light-combustion efficiency. DETAILED DESCRIPTION

[0018] In order to clearly illustrate the technical features of this patent, this patent is described in detail below through specific implementation methods and in combination with its accompanying drawings.

[0019] like Figure 1 、 2As shown, it includes a reactor 1, a guide plate 4, and a multi-layer reflux baffle. The multi-layer reflux baffle is divided into a primary reflux baffle 7, a secondary reflux baffle 6, and a tertiary reflux baffle 5. The front end of the reactor 1 is a solar radiation energy flow receiving end 2, the rear edge is a reaction gas inlet 8, and the middle of the rear end is a synthesis gas outlet 9. The reactor has a guide baffle 4 and three reflux baffles of different sizes. The guide baffle 4 and the multi-layer reflux baffles separate the gas inlet and outlet, allowing the reaction gas to enter the reactor from the rear end, undergo heating and reaction in the front section, and then flow out from the rear end. This design is mainly to use the high-temperature generated gas to preheat the lower temperature inlet raw gas, strengthen the heat exchange inside the reactor, increase the overall temperature inside the reactor, and then expand the high-temperature zone, increase the overall reaction rate, and thus improve the reaction gas conversion rate and system efficiency.

[0020] The working process is as follows: gas is fed in through the raw gas inlet pipe 11 connected to the raw gas inlet 8, and gas is led out through the synthesis gas outlet pipe 10 connected to the reaction gas outlet 9.

[0021] Specifically, a mixture of methane, carbon dioxide, and water vapor enters reactor 1 through inlet 8 at the rear edge, passing through primary reflux baffle 7, secondary reflux baffle 6, tertiary reflux baffle 5, and guide plate 4. During this process, the mixture is preheated to a certain temperature by the porous medium and each baffle, allowing for reaction. The mixture then passes through reactor radiation receiving end 2 and the center of the reactor, where it is further heated and reacts. The resulting synthesis gas flows out through synthesis gas outlet 9. Because reactor 1 is equipped with guide baffle 4 and three layers of reflux baffles, the higher-temperature synthesis gas can also preheat the feed gas entering the reactor through inlet 8 before flowing out through outlet 9.

[0022] The internal structure of the reactor 1 is a porous medium structure with a porosity of 0.93 and an average pore diameter of 2 mm. The porous matrix material is copper, nickel and a high-temperature alloy containing these two elements. The catalyst uses a catalyst based on Ni, Co, Si, Cu, Al, Ag or Rh.

[0023] Figure 3 The present invention demonstrates the fluid temperature distribution of a conventional reactor and the fluid temperature distribution of the reactor described in the present invention under different inlet flow conditions. Clearly, after using the present invention, at each calculated flow rate, the maximum and overall fluid temperatures are higher than those of conventional reactors. Higher fluid temperatures translate to faster reaction rates, and more raw materials react within the same residence time. Furthermore, after setting up a three-stage reflux, it can be clearly seen that the temperature of the core high-temperature zone of the reactor is transferring heat to the low-temperature inlet. This demonstrates that the present invention can enhance the heat exchange process within the reactor, improve the overall temperature and temperature uniformity within the reactor, and thereby achieve higher reaction gas conversion rates and system efficiency.

[0024] Figure 4 The results demonstrate the methane and carbon dioxide conversion rates and light-to-combustion efficiency (the efficiency of converting solar energy into chemical energy) of the present invention and conventional reactors under the calculated condition of an incident radiation power of 130.8W. The results show that, compared to conventional reactors, the application of the present invention can effectively improve the efficiency of material and energy conversion. Specifically, at lower flow rates, the methane conversion rate can be increased by 11.2%, the carbon dioxide conversion rate can be increased by 9.0%, and the light-to-combustion efficiency can be increased by 6.23%. In summary, the solar dual-process reactor of the present invention, which incorporates three-stage reflux diversion control, significantly improves the energy utilization efficiency of the solar methane dual-process reactor.

[0025] There are many specific implementation ways of the present invention. The above is only the preferred implementation method of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be considered as the scope of protection of the present invention.

Claims

1. A solar double reactor with a circuitous flow guiding structure, characterized in that: It comprises a reactor (1) and a heat-insulating layer (3) wrapped around the outside of the reactor (1), wherein one end of the reactor (1) is a solar radiation energy flow receiving end (2), and the other end is a gas inlet and outlet end; The reactor (1) is further embedded with a cylindrical guide plate (4), the axial length of the guide plate (4) being smaller than that of the reactor (1) and extending to the gas inlet and outlet ends, the inner side of the guide plate (4) being a reaction gas outlet (9), a circuitous guide structure embedded in the reactor is provided between the guide plate (4) and the thermal insulation layer (3), the terminal end of the circuitous guide structure being a raw gas inlet (8).

2. The solar double reactor with a circuitous flow guiding structure according to claim 1, characterized in that: The circuitous guide structure comprises a reflux baffle fixedly connected to the inner wall of the heat insulation layer (3) and a spacing plug fixedly connected to the outer wall of the guide plate (4). The reflux baffle and the spacing plug are both annular and are alternately arranged at equal intervals. A spacing is left between the inner wall of the reflux baffle and the outer wall of the guide plate (4), and between the outer wall of the spacing plug and the inner wall of the heat insulation layer (3), thereby forming a circuitous raw gas inlet channel between the guide plate (4) and the heat insulation layer (3).

3. The solar dual reactor with a circuitous flow guiding structure according to claim 2, characterized in that: There are three reflux baffles, which are, from outside to inside, a primary reflux baffle (7), a secondary reflux baffle (6), and a tertiary reflux baffle (5), and the inner diameters of the three reflux baffles increase in sequence; the guide plate (4) is in a stepped cylindrical shape that gradually increases in size from outside to inside.

4. The solar dual reactor with a circuitous flow guiding structure according to claim 1, characterized in that: The internal structure of the reactor (1) is a porous medium structure, the porosity of the porous medium is 0.93, and the average pore diameter is 2 mm.

5. The solar dual reactor with a circuitous flow guiding structure according to claim 4, characterized in that: The porous medium structure is mainly composed of copper, nickel and high-temperature alloys containing these two elements.

6. The solar dual reactor with a circuitous flow guiding structure according to claim 4, characterized in that: The reactor further comprises an inner catalyst coated on the porous medium structure, wherein the catalyst is a catalyst having Ni, Co, Si, Cu, Al, Ag or Rh as a matrix.

7. The solar dual reactor with a circuitous flow guiding structure according to claim 1, characterized in that: The reactor (1) has a cylindrical shape and a cylindrical diameter. D =2 cm, cylinder height H =2 cm.

8. The solar dual reactor with a circuitous flow guiding structure according to claim 1, characterized in that: The thickness of the guide baffle (4), the spacer insert and the return baffle are all d c =0.25 mm; the height of the guide baffle (4) from the solar radiation energy flow receiving end (2) h =2 mm, the cross-sectional lengths of the first-stage reflux baffle (7), the second-stage reflux baffle (6) and the third-stage reflux baffle (5) are respectively d 3=8 mm, d 2=6 mm, d 1=4 mm, the size of the raw gas inlet (8) and the circuitous raw gas inlet channel are d in =2 mm, the distance between the guide plate (4) and the insulation layer (3) after the raw gas enters the channel d 0=2 mm.

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