A thermally coupled reaction unit and reactor

Abstract

The application discloses a heat-coupled reaction unit and a reactor. The heat-coupled reaction unit comprises multiple groups of basic tubes which are arranged in parallel in sequence. The basic tube comprises a feeding end, an endothermic reaction section and a discharging end which are connected in sequence. The endothermic reaction sections of the multiple groups of basic tubes are connected in parallel in a ring shape to form multiple tubular reaction channels. The reaction channels can carry out exothermic reaction or pass through a flowable exothermic medium. The endothermic reaction section of the basic tube can carry out endothermic reaction. The reactor comprises the heat-coupled reaction unit. The heat-coupled reaction unit and the reactor are used for methanol reforming to produce hydrogen. The hydrogen produced has low CO concentration. The heat source has stable temperature, good heat exchange effect and high system integration.

Description

Technical Field

[0001] This invention relates to the field of methanol reforming for hydrogen production, specifically to a thermally coupled reaction unit and reactor. Background Technology

[0002] With the rapid development of the global economy, the world's energy and environmental crises are becoming increasingly severe. Given my country's basic energy situation—abundant coal (especially low-quality coal), scarce oil, and limited natural gas—finding green and clean new energy sources to replace traditional fossil fuels has become a primary task for my country to achieve sustainable development.

[0003] Among various new energy sources, hydrogen energy has become one of my country's emerging energy sources for the 21st century due to its combustion byproduct being only water and its high calorific value. Based on this, Chinese experts and scholars have proposed the concept of "in-situ hydrogen production." This involves producing hydrogen through the reforming of hydrocarbon alcohols in portable devices and using the hydrogen as the anode feedstock in a fuel cell system to provide the energy required for operation. Methanol has become a preferred choice for "in-situ hydrogen production" due to its pollution-free combustion, low reaction temperature, liquid state at room temperature, and high yield.

[0004] Existing methanol reforming hydrogen production reactors are mainly classified into four categories: tubular reactors, membrane reactors, plate reactors, and microreactors. Among them, microreactors, due to their small size, good heat transfer performance, and portability, have attracted researchers both domestically and internationally to design and study microchannels, catalysts, and catalyst supports for methanol reforming hydrogen production microreactors. However, current methanol reforming hydrogen production microreactors suffer from problems such as high CO concentration in the produced hydrogen (preventing direct coupling with low-temperature fuel cells), unpredictable heat source, poor heat exchange efficiency, and low system integration. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a thermally coupled reaction unit and reactor that, when used in methanol reforming for hydrogen production, can solve the problems of high CO concentration in the hydrogen produced by existing methanol reforming reactors, unpredictable heat source, poor heat exchange effect, and low system integration.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a thermally coupled reaction unit, comprising multiple sets of basic tubes, wherein the multiple sets of basic tubes are arranged in parallel and sequentially, each basic tube comprising a feed end, an endothermic reaction section and a discharge end connected in sequence, wherein the endothermic reaction sections of the multiple sets of basic tubes are connected in parallel in a ring to form multiple tubular reaction channels, wherein the reaction channels can carry out exothermic reactions or allow the flow of exothermic media, and wherein the endothermic reaction sections of the basic tubes can carry out endothermic reactions and release substances.

[0007] Furthermore, the endothermic reaction section is coiled in a ring shape, and the endothermic reaction section moves forward in a ring shape from the feed end, and then turns back in a ring shape to the discharge end to form multiple tubular reaction channels.

[0008] Furthermore, the endothermic reaction section includes at least a steam reforming reaction tube and a water vapor displacement reaction tube.

[0009] Furthermore, the steam reforming reaction tube and the water-gas displacement reaction tube are symmetrically distributed vertically.

[0010] Furthermore, the steam reforming reaction tube is a metal alloy tube, and the water-gas displacement reaction tube is a metal alloy tube, with an endothermic reaction catalyst disposed inside each tube.

[0011] Furthermore, an exothermic reaction catalyst may be provided inside the tubular reaction channel.

[0012] A thermally coupled reactor includes the thermally coupled reaction unit described in any one of the above claims, and further includes a shell, the reaction channel being located inside the shell, one end of the reaction channel being connected to the inner wall of the shell, the other end of the reaction channel being connected to the outside, and the inlet end and the outlet end extending from the side wall of the shell.

[0013] Furthermore, it also includes a supply device located outside the housing and capable of being connected to the ends of the plurality of feed ends.

[0014] Furthermore, it also includes a temperature sensor, which is disposed within the reaction channel and electrically connected to the valve of the supply device.

[0015] The beneficial effects of this invention are:

[0016] The above-mentioned thermally coupled reaction unit and reactor are used for methanol reforming to produce hydrogen. The methanol steam reforming reaction, methanol water vapor displacement reaction and exothermic reaction are organically combined and integrated into a single design. This allows the entire reactor to produce high-purity hydrogen with a CO concentration of less than 10 ppm by sequentially passing methanol aqueous solution or methanol steam through the steam reforming reaction tube and the water vapor displacement reaction tube under certain flow conditions. This results in high-purity hydrogen that can be directly fed into a low-temperature proton exchange membrane fuel cell for use.

[0017] Since exothermic reactions release heat, and both methanol steam reforming and water vapor displacement reactions require high temperatures to proceed, the heat released by the exothermic reaction can be utilized to achieve a self-heating operating condition without the need for additional heat supply.

[0018] Furthermore, since the heat of the exothermic reaction is confined within the reaction channel, heat loss can be effectively prevented, greatly improving heat utilization. As the reaction channel is composed of multiple basic tubes wound together, the heat generated by the exothermic reaction or the heat of the exothermic medium is directly transferred to the basic tubes, which can further enhance the convective heat transfer between the endothermic and exothermic reactions. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0020] Figure 1 This is a schematic diagram of a thermally coupled reaction unit provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of a reactor provided according to an embodiment of the present invention;

[0022] Figure label:

[0023] 1. Outer shell; 2. Reaction channel; 3. Basic tube; 31. Feed end; 32. Endothermic reaction section; 321. Steam reforming reaction tube; 322. Water vapor displacement reaction tube; 33. Discharge end; 4. Temperature sensor. Detailed Implementation

[0024] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0025] Please see Figures 1 to 2 This invention provides a thermally coupled reaction unit that can be used for methanol reforming to produce hydrogen. It includes multiple sets of basic tubes 3, which are arranged in parallel. Each basic tube 3 includes a feed end 31, an endothermic reaction section 32, and a discharge end 33 connected in sequence. The endothermic reaction sections 32 of the multiple sets of basic tubes 3 are connected in parallel to form a tubular reaction channel 2. The reaction channel 2 can carry out an exothermic reaction, and the endothermic reaction section 32 of the basic tube 3 can carry out an endothermic reaction to release a substance, which can be a gas, liquid, or solid.

[0026] In the methanol reforming to produce hydrogen using this thermally coupled reaction unit, the endothermic reaction section 32 includes at least a steam reforming reaction tube 321 and a water-gas displacement reaction tube 322. In specific implementation, a steam reforming reaction catalyst can be placed in the steam reforming reaction tube 321, a water-gas displacement reaction catalyst can be placed in the water-gas displacement reaction tube 322, and an exothermic reaction catalyst can be placed in the reaction channel 2. When a gas that can react exothermically with the exothermic reaction catalyst is introduced into the reaction channel 2, the gas reacts exothermically with the exothermic reaction catalyst to release heat. When an aqueous methanol solution is introduced into the steam reforming reaction tube 321 through the feed end 31, methanol reforming to produce hydrogen can be carried out.

[0027] Of course, in practical implementation, this thermally coupled reaction unit can also be used in other reforming reactions that can use exothermic and endothermic reactions to thermally couple with each other to produce gas.

[0028] The methanol steam reforming catalyst is preferably 2% Pt / α-MoC catalyst powder, and the water-gas shift reaction catalyst is preferably Cu-ZnO catalyst powder. When a methanol aqueous solution is introduced into the steam reforming reaction tube 321 through the feed end 31, the methanol aqueous solution first flows into the steam reforming reaction tube 321 and absorbs the heat in the reaction channel 2, and undergoes a reforming reaction with the methanol steam reforming reaction catalyst. The reaction formula is (1), accompanied by two side reactions: methanol decomposition reaction (2) and reverse water-gas shift reaction (3).

[0029] CH3OH + H2O → CO2 + 3H2 (1)

[0030] CH3OH→CO+2H2

[0031] CO2 + H2 → CO + H2O

[0032] After the methanol-water solution undergoes a reforming reaction, it continues to flow forward and enters the water-gas displacement reaction tube 322, where it continues to absorb heat from the reaction channel 2. It then reacts with the water-gas displacement reaction catalyst powder in the water-gas displacement reaction tube 322 to produce hydrogen. The reaction formula is (4):

[0033] CO + H₂O → CO₂ + H₂ (4)

[0034] Finally, hydrogen gas containing a small amount of CO is directly introduced into the cryogenic proton exchange membrane fuel cell from the discharge end 33.

[0035] This device is used for methanol reforming to produce hydrogen. It organically combines methanol steam reforming, water vapor displacement reaction and exothermic reaction in an integrated design. Under certain flow conditions, the methanol aqueous solution passes through the methanol steam reforming tube and the water vapor displacement tube in sequence to produce high-purity hydrogen with a CO concentration of less than 10 ppm, which can be directly fed into a low-temperature proton exchange membrane fuel cell for use.

[0036] Since exothermic reactions release heat, while methanol steam reforming and water vapor displacement reactions both require endothermic reactions, the heat released by the exothermic reaction can be used to carry out the reaction, thus achieving a good self-heating operation without the need for additional heat supply.

[0037] Furthermore, since the heat of the exothermic reaction is confined within the reaction channel 2, heat loss can be prevented, which can greatly improve the heat utilization rate. Since the reaction channel 2 is composed of multiple basic tubes 3 wound together, the heat generated by the exothermic reaction is directly transferred to the basic tubes 3, which can further enhance the convective heat transfer between the endothermic and exothermic reactions.

[0038] In practical implementation, the exothermic reaction catalyst can preferably be a methanol catalytic combustion catalyst, such as a Pt / Al2O3 catalyst. By introducing a mixture of methanol and air into reaction channel 2, the flow heat exchange process is the methanol catalytic combustion process within reaction channel 2. The methanol and air mixture releases heat under the catalytic action of the Pt / Al2O3 catalyst. The highly efficient Pt / Al2O3 catalyst allows the methanol catalytic combustion reaction to ignite at room temperature without heating, aiming to achieve self-heating start-up at room temperature. Simultaneously, the methanol and air mixture is similar in material to methanol-water solutions, making it convenient to obtain the material.

[0039] In this embodiment, the endothermic reaction section 32 is arranged in a ring. When multiple basic tubes 3 are arranged side by side and connected, the multiple rings can form a reaction channel 2. Of course, in other embodiments, other arrangements are also used to arrange the rings in parallel to form a reaction channel. For example, two basic tubes are grouped together, and the endothermic reaction section of each basic tube advances in an S-shape. When the endothermic reaction sections of the two basic tubes in the same group are symmetrical, a closed ring can be formed. When multiple groups of basic tubes are arranged in parallel, a reaction channel can also be formed.

[0040] In a preferred embodiment, the endothermic reaction section 32 advances in a ring shape from the feed end 31 and then returns in a ring shape to the discharge end 33, forming multiple reaction channels 2. This method significantly reduces the volume of the entire thermally coupled reaction unit, minimizes heat loss, and further improves heat utilization.

[0041] As a more efficient implementation, the number of reaction channels 2 can be odd, allowing the steam reforming reaction tube 321 and the water vapor displacement reaction tube 322 to be symmetrically distributed vertically. For example, when arranging the basic tube 3, the steam reforming reaction tube 321 can be coiled sequentially from left to right in a ring around the outer shell 1. After the last reaction channel 2 is completed, the steam reforming reaction tube 321 is finished coiling. Then, the coiling continues in the opposite direction, from right to left, to coil the water vapor displacement reaction tube 322. This ensures that the methanol steam reforming reaction and the water vapor displacement reaction are evenly and neatly distributed, and that the discharge end 33 and the feed end 31 are located on the same side. Of course, the number of reaction channels 2 can also be even, with the discharge end 33 and the feed end 31 located on opposite sides.

[0042] In practical implementation, both the steam reforming reaction tube 321 and the water-gas displacement reaction tube 322 should be metal alloy tubes. Metal alloy tubes have good rigidity, hardness, and thermal conductivity. Copper alloy tubes or aluminum alloy tubes can be used, but aluminum alloy is preferred due to its low price. Aluminum alloy has high thermal conductivity and low density, resulting in a reactor with good heat transfer performance and light weight. Furthermore, the aluminum alloy tube diameter can be 10 mm and the wall thickness can be 1 mm.

[0043] The present invention also provides a thermally coupled reactor, which includes the aforementioned thermally coupled reaction unit and a shell 1. A reaction channel 2 is located inside the shell 1, and one end of the reaction channel 2 is connected to the inner wall of the shell 1, while the other end of the reaction channel 2 is connected to the outside. An inlet end 31 and an outlet end 33 extend from the side wall of the shell 1.

[0044] In practice, the outer shell 1 should be made of heat-insulating material. The outer shell 1 facilitates operation and further prevents the entire reaction from exchanging heat with the outside environment.

[0045] In practical implementation, this reactor may also include an aqueous solution supply device. Figure 2 (Not shown in the image) The aqueous solution supply device is located outside the housing 1 and can be connected to the ends of all feed ends. It can continuously supply aqueous solution or gas for methanol steam reforming reaction and water-gas displacement reaction into the basic tube 3. When methanol reforming to produce hydrogen, the aqueous solution is methanol aqueous solution and the gas is methanol gas.

[0046] In addition, this reactor also includes a temperature sensor 4 ( Figure 1 As shown in the figure, a temperature sensor 4 is installed in the reaction channel 2. During use, the temperature sensor 4 can be electrically connected to the valve of the aqueous solution supply device, and the temperature change of the reaction channel 2 causes the opening degree of the valve of the aqueous solution supply device to change, thereby controlling the heat absorption and release coupling of the reaction in the reaction channel 2.

[0047] The above-mentioned self-heating thermally coupled reaction unit and reactor are used for methanol reforming to produce hydrogen, and their operating principles are as follows:

[0048] First, ensure that the inner wall of the steam reforming reaction tube 321 is coated with a methanol steam reforming reaction catalyst, and the inner wall of the water-gas displacement reaction tube 322 is coated with a water-gas displacement reaction catalyst. Then, connect the reaction channel 2 to the catalyst supply device, connect all feed ends 31 to the aqueous solution supply device, and connect the discharge end 33 to an external receiver such as a low-temperature proton exchange membrane fuel cell. When a methanol-air mixture and methanol catalyst are introduced into the reaction channel 2, the methanol gas reacts with the catalyst and burns, releasing a large amount of heat. Then, a methanol-water solution is introduced into the feed end 31, and the methanol-water solution flows sequentially into the steam reforming reaction tube 321 and the water-gas displacement reaction tube 322, producing a methanol steam reforming reaction and a water-gas displacement reaction. Finally, the generated hydrogen gas flows from the discharge end 33 into the low-temperature proton exchange membrane fuel cell.

[0049] This reactor and method organically combine methanol steam reforming, water-gas displacement reaction and methanol catalytic combustion reaction into an integrated design. Under certain flow conditions, the methanol aqueous solution passes sequentially through the steam reforming reaction tube 321 and the water-gas displacement reaction tube 322 to obtain high-purity hydrogen with a CO concentration of less than 10 ppm, which can then be directly fed into a low-temperature proton exchange membrane fuel cell for use.

[0050] Since exothermic reactions release heat, and both methanol steam reforming and water vapor displacement reactions require high temperatures to proceed, the heat released from the reaction of methanol gas with the methanol catalyst can be utilized to achieve a self-heating operating condition without the need for additional heat supply.

[0051] The specific flow heat exchange process is the methanol catalytic combustion process in reaction channel 2. The highly efficient Pt / Al2O3 catalyst enables the methanol catalytic combustion to start at room temperature without heating, thus achieving self-heating start at room temperature.

[0052] Furthermore, since the heat released by the reaction of methanol gas with methanol catalyst is confined within reaction channel 2, heat loss can be prevented, which can greatly improve the heat utilization rate. At the same time, since reaction channel 2 is composed of multiple basic tubes 3 wound together, the heat generated by the exothermic reaction is directly transferred to the basic tubes 3, which can further enhance the convective heat transfer between endothermic and exothermic reactions.

[0053] Considering that the enthalpy of the catalytic combustion reaction is much higher than the sum of the enthalpies of the two endothermic reactions, the overall thermal efficiency of the system is improved. By combining the temperature sensor 4 with the catalyst supply device, the entire reactor can perform high-temperature gas and basic tube 3 to circulate heat exchange when the heat after heat exchange is still sufficient to maintain the normal operation of the hydrogen production system. When the heat of the catalytic combustion gas after heat exchange is insufficient to maintain the normal operation of the reaction system, the catalyst supply device will control the continued supply of catalytic combustion reactants to maintain the normal operation of the system.

[0054] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A thermally coupled reaction unit, characterized in that, It includes multiple sets of basic tubes, which are arranged in parallel and sequentially. Each basic tube includes an inlet end, an endothermic reaction section, and an outlet end connected in sequence. The endothermic reaction sections of the multiple sets of basic tubes are connected in parallel in a ring to form multiple tubular reaction channels. The reaction channels can carry out exothermic reactions or allow the flow of exothermic media. The endothermic reaction sections of the basic tubes can carry out endothermic reactions and release substances. The endothermic reaction section is coiled in a ring shape, and the endothermic reaction section moves forward in a ring shape from the feed end, and then turns back in a ring shape to the discharge end to form multiple tubular reaction channels. The endothermic reaction section includes at least a steam reforming reaction tube and a water vapor displacement reaction tube; The steam reforming reaction tube and the water vapor displacement reaction tube are symmetrically distributed vertically. An exothermic reaction catalyst may be placed inside the tubular reaction channel.

2. The thermally coupled reaction unit according to claim 1, characterized in that, The steam reforming reaction tube is a metal alloy tube, and the water vapor displacement reaction tube is a metal alloy tube, with an endothermic reaction catalyst installed inside each tube.

3. A thermally coupled reactor, comprising the thermally coupled reaction unit as described in any one of claims 1-2, characterized in that, The device includes a housing, the reaction channel is located inside the housing, one end of the reaction channel is connected to the inner wall of the housing, the other end of the reaction channel is connected to the outside, and the inlet end and the outlet end extend from the side wall of the housing.

4. The thermally coupled reactor according to claim 3, characterized in that, It also includes a supply device located outside the housing and capable of being connected to the ends of the plurality of feed ends.

5. The thermally coupled reactor according to claim 4, characterized in that, It also includes a temperature sensor, which is disposed in the reaction channel and electrically connected to the valve of the supply device.

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