Reactor for producing hydrogen through catalytic cracking of methane and method for producing hydrogen through catalytic cracking of methane

Abstract

The invention provides a reactor for producing hydrogen through catalytic cracking of methane. The reactor comprises a pipe barrel, an upper sealing head connected to the upper end of the pipe barrel and a lower sealing head connected to the lower end of the pipe barrel, the catalyst basket is arranged in the pipe barrel; the supporting pipe is of a hollow structure, the two ends of the supporting pipe are open ends, the upper open end of the supporting pipe is connected to the bottom of the catalyst basket, and the lower open end of the supporting pipe abuts against the top of the lower sealing head; the thermocouple sleeve is arranged in the supporting pipe in a penetrating manner, the upper end of the thermocouple sleeve extends into the catalyst basket along with the upper opening end of the supporting pipe, and the lower end of the thermocouple sleeve extends out of the lower end of the lower sealing head. The reactor can be used for conveniently filling a catalyst and is simple to operate, so that the catalytic reaction evaluation of methane catalytic cracking hydrogen production is accurate, rapid and efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen preparation, and in particular to a reactor for producing hydrogen by catalytic cracking of methane and a method for producing hydrogen by catalytic cracking of methane. Background Art

[0002] Hydrogen is an important fuel and industrial raw material. Traditional methods of hydrogen production mainly rely on water electrolysis and high-temperature and high-pressure steam conversion of hydrocarbons such as methane. Among them, the methane steam reforming process is relatively mature in industrial application, but the traditional hydrogen production process has disadvantages such as high energy consumption, high cost, and large investment. In recent years, people have developed a new technology for hydrogen production by catalytic cracking of methane. By cracking methane, carbide-free hydrogen and carbon nanotubes can be prepared. Since these two important products can be obtained at the same time, this route has attracted the attention of many researchers.

[0003] The key to hydrogen production from catalytic cracking of methane is to select an efficient catalyst. The quality and effect of a catalyst are measured mainly by examining three comprehensive indicators: activity, selectivity and life. At present, the performance of catalysts is generally evaluated and analyzed using fixed-bed reactors. However, due to various limitations, many conventional laboratory catalyst evaluation devices basically use quartz tubes or stainless steel tubes as fixed-bed reactors, which generally have disadvantages such as large fluid flow resistance, poor heat transfer, and difficult temperature control.

[0004] Chinese patent CN215974954U discloses a liquid metal high-temperature cracking methane hydrogen production reactor with catalytic function. Under the action of the catalyst, methane gas undergoes low-temperature catalytic dehydrogenation. X H Y The air entering the hydrogen production reactor is cracked into hydrogen, and the air entering the reactor is evacuated by a vacuum pump, etc., to reduce the generation of CO2 and improve the efficiency of hydrogen production. However, this hydrogen production reactor has a complex structure and cumbersome experimental operation. Chinese patent CN105013506A discloses a bifunctional catalyst for catalytic cracking of methane, its preparation method and hydrogen production method, and proposes that the catalyst can be used to catalyze methane to produce hydrogen at a lower temperature, and selectively oxidize carbon deposits to CO; the method uses a circulating fluidized bed reactor and a regenerator to catalytically crack the feed gas including methane to produce hydrogen and regenerate and reuse the catalyst; however, the patent uses multiple devices, resulting in overly complicated operations. In summary, traditional catalytic evaluation methods are labor-intensive, inefficient, and the experimental data obtained are not accurate enough.

[0005] In summary, the existing catalyst evaluation methods have problems such as cumbersome experiments, large errors, labor-intensive and low efficiency. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned prior art, the present invention provides a reactor for producing hydrogen by catalytic cracking of methane and a method for producing hydrogen by catalytic cracking of methane. The reactor can facilitate the loading of the catalyst and is simple to operate, thereby making the catalytic reaction evaluation of producing hydrogen by catalytic cracking of methane accurate, rapid and efficient.

[0007] In order to achieve the above object, the present invention provides a reactor for producing hydrogen by catalytic cracking of methane, comprising:

[0008] A tube, an upper end cap connected to the upper end of the tube, and a lower end cap connected to the lower end of the tube;

[0009] A catalyst basket is disposed in the tube;

[0010] A support tube, wherein the support tube is a hollow structure with both ends being open ends, the upper open end of the support tube being connected to the bottom of the catalyst basket, and the lower open end of the support tube being pressed against the top of the lower head;

[0011] Thermocouple sleeve, the thermocouple sleeve is inserted into the support tube, the upper end of the thermocouple sleeve extends into the catalyst basket along the upper opening end of the support tube, and the lower end of the thermocouple sleeve extends out of the lower end of the lower head.

[0012] In some of the embodiments, a lining is provided on the inner wall of the tube near the upper end, and the bottom of the catalyst basket is pressed against the surface of the lining to fix the catalyst basket.

[0013] In some of the embodiments, the catalyst basket is open, cylindrical in shape, and has a conical bottom.

[0014] In some of the embodiments, an annular mounting groove and a cross baffle are provided at the bottom of the catalyst basket, and a mesh screen is covered on the cross baffle.

[0015] In some embodiments, the lower end of the support tube is provided with an external thread, and a compression spring and a compression nut are arranged outside the support tube between the tube and the lower head to form tension so that the bottom of the catalyst basket is pressed against the tube and the liner, thereby fixing the catalyst basket.

[0016] In some of the embodiments, a rectifying grid plate mounting groove for mounting a rectifying grid plate is provided in the tube above the catalyst basket, and a sealing ring is provided in the rectifying grid plate mounting groove.

[0017] In some of the embodiments, the rectifying grid plate is placed on a step surface where the circular inner cavity at the upper end of the tube meets the working cavity; the holes inside the rectifying grid plate are evenly distributed along the axial direction of the tube.

[0018] In some embodiments, the upper end of the tube is connected to the connecting piece by a flange, and the connecting piece is connected to the upper head.

[0019] In some of the embodiments, a reaction tube inlet is provided above the tube, and a reaction tube outlet is provided on the side wall above the bottom head of the tube.

[0020] The present invention also provides a method for producing hydrogen by catalytic cracking of methane, using the above-mentioned reactor for producing hydrogen by catalytic cracking of methane, comprising the following steps:

[0021] S1. Before conducting the experiment of catalytic cracking of methane to produce hydrogen, the upper head, flange and rectifier grid plate of the reactor are first removed, a certain amount of catalyst is weighed and placed in the catalyst basket, and before filling, the cross baffle at the bottom of the catalyst basket needs to be covered with a stainless steel microporous square screen; the rectifier grid plate, connector and upper head at the upper end of the reactor tube are fastened, and then the lower end of the reactor tube is fastened with the lower head, and the thermocouple is inserted into its sleeve so that the top of the thermocouple is inside the catalyst basket, and then the reactor is selected and placed in the heating furnace, so that the catalyst basket is located in the heating furnace, and the catalyst basket is located in the middle of the heating section of the heating furnace, and then the experiment is started;

[0022] S2. First, introduce inert gas nitrogen to remove the air in the tube, and heat the reactor at the same time, set the reduction temperature to 200°C-500°C, and the reduction pressure to normal pressure. When the reduction temperature of the catalyst is reached, cut off the nitrogen, introduce reducing gas hydrogen, and keep the temperature constant to reduce the catalyst;

[0023] S3. After the reduction is completed, the hydrogen valve is closed, and the temperature is rapidly raised under nitrogen purge until the gas chromatograph no longer detects hydrogen, and then methane is introduced to start the reaction;

[0024] S4. After the experiment, take out the reactor from the heating furnace, disassemble the various components of the reactor in reverse order, take out the catalyst sample in the catalyst basket, and weigh it.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The reactor for producing hydrogen by catalytic cracking of methane provided by the present invention has a simple structure and is easy to disassemble; a hollow support tube is used to connect the bottom center of a catalyst basket, and the hollow support tube can fix the catalyst basket inside the reactor; the hollow support tube is connected to a thermocouple sleeve, which can reduce the internal components of the reactor, increase the effective space of the reactor, and facilitate the rapid outflow of the product from the reactor; a stainless steel metal screen is arranged at the bottom of the catalyst basket, which can effectively prevent the catalyst core or generated coke particles from entering a subsequent reaction pipeline, so as to avoid clogging the reaction tube and prevent the catalyst evaluation experiment from being forced to stop. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a flowchart of the process of producing hydrogen by catalytic cracking of methane shown in an embodiment of the present invention;

[0029] Figure 2 This is a schematic structural diagram of a reactor for producing hydrogen through catalytic cracking of methane as shown in an embodiment of the present invention;

[0030] Figure 3 It is a schematic diagram of the matching structure of the catalyst basket, the support tube, and the thermocouple sleeve shown in the embodiment of the present invention;

[0031] Figure 4 It is a schematic diagram of the mesh structure of the catalyst basket shown in an embodiment of the present invention;

[0032] Figure 5 A bottom plan view of a catalyst basket shown in an embodiment of the present invention;

[0033] in:

[0034] 1-tube;

[0035] 101 - lining;

[0036] 102-reaction tube inlet;

[0037] 103-reaction tube outlet;

[0038] 2- Upper head;

[0039] 3-Lower head;

[0040] 4-Catalyst basket;

[0041] 401-annular mounting groove;

[0042] 402-cross baffle;

[0043] 403-mesh screen;

[0044] 5- Support tube;

[0045] 6-Thermocouple sleeve;

[0046] 7-Compression spring;

[0047] 8-Compression nut;

[0048] 9-rectifier grid plate;

[0049] 10-rectifier grid plate installation slot;

[0050] 11- Sealing ring;

[0051] 12-Connector;

[0052] 13-Flange. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments to further understand the purpose, solution and effect of the present invention, but it is not intended to limit the scope of protection of the claims attached to the present invention.

[0054] Certain words are used in the specification and subsequent claims to refer to specific components or parts. It should be understood by those of ordinary skill in the art that technical users or manufacturers may refer to the same component or part by different nouns or terms. This specification and subsequent claims do not use differences in names as a way to distinguish components or parts, but use differences in the functions of components or parts as the criteria for distinction. "Including" and "comprising" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the word "connect" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connection through other devices.

[0055] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and "about", or "approximately", "substantially", "left and right" and the like indicating directions or positional relationships or parameters are all based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description content, and do not indicate or imply that the referred device or element must have a specific direction, specific size, or be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0056] The first embodiment of the present invention provides a reactor for producing hydrogen by catalytic cracking of methane, comprising: a tube 1, an upper head 2 connected to the upper end of the tube 1, and a lower head 3 connected to the lower end of the tube 1, wherein the bottom of the tube 1 is threadedly connected to the lower head 3; the upper head 2 and the lower head 3 are respectively detachably connected to the tube 1; the tube 1 in this embodiment is a stainless steel tube with a length of 600 mm, an outer diameter of 40 mm, and a wall thickness of 4 mm. Catalyst basket 4, arranged in the tube 1, the catalyst basket 4 corresponds to the middle position of the heating section of the electric heating furnace; support tube 5, in this embodiment, the length of the support tube 5 is 330mm, the outer diameter is 6mm, and the wall thickness is 2mm; the support tube 5 is a hollow structure, both ends of which are open ends, the upper open end of the support tube 5 is connected to the bottom center of the catalyst basket 4, and the lower open end of the support tube 5 is tightly against the top of the lower head 3; thermocouple sleeve 6, the thermocouple sleeve 6 is penetrated in the support tube 5, the upper end of the thermocouple sleeve 6 extends into the catalyst basket 4 along with the upper open end of the support tube 5, and the lower end of the thermocouple sleeve 6 extends out of the lower end of the lower head 3. A thermocouple for measuring the catalyst temperature is arranged in the thermocouple sleeve 6. In this embodiment, the outer diameter of the thermocouple sleeve 6 is 4mm, the wall thickness is 1mm, and the inner diameter of the thermocouple is 2mm.

[0057] Among them, the inner wall of the tube 1 is provided with an inner lining 101 at 300 mm near the top end, and the bottom of the catalyst basket 4 is pressed against the surface of the inner lining 101 to fix the catalyst basket 4; the catalyst basket 4 is open, cylindrical as a whole, and conical at the bottom. The outer diameter of the top of the basket cylinder is 24 mm, the outer diameter of the bottom is 20 mm, the wall thickness is 1 mm, and the height is 40 mm; the bottom of the catalyst basket 4 is provided with an annular mounting groove 401 and a cross baffle 402, and the cross baffle 402 is covered with a stainless steel microporous square mesh 403.

[0058] Among them, the lower end of the support tube 5 is provided with an external thread, and a clamping spring 7 and a clamping nut 8 are arranged outside the support tube 5 between the tube 1 and the lower head 3 to form tension so that the bottom of the catalyst basket 4 is pressed against the tube 1 and the liner 101, thereby fixing the catalyst basket 4.

[0059] In this embodiment, a rectifying grid plate installation groove 10 for installing a rectifying grid plate 9 is provided in the tube 1 above the catalyst basket 4, and a sealing ring 11 is provided in the rectifying grid plate installation groove 10. The rectifying grid plate 9 is placed on the step surface where the circular inner cavity at the upper end of the tube and the working cavity meet; the holes inside the rectifying grid plate 9 are evenly distributed along the axial direction of the tube 1. The rectifying grid plate 9 makes the reaction gas passing through uniform in speed and distribution, so that the gas flows in the reaction tube along the axial direction of the catalyst reaction tube, the gas phase flow velocity is evenly distributed, and the gas flow back mixing is avoided.

[0060] In this embodiment, the upper end of the tube 1 is connected to the connector 12 by a flange 13, and the connector 12 is threadedly connected to the upper head 2. A reaction tube inlet 102 is provided above the tube 1, and the tube 1 and the reaction tube inlet 102 are flange-connected. The reaction tube inlet 102 is a stainless steel tube with an outer diameter of 8 mm and a wall thickness of 1 mm. A reaction tube outlet 103 is provided on the side wall above the bottom head of the tube 1 at a distance of 50 mm from the lower end of the tube 1. In this embodiment, the reaction tube inlet 102 is threadedly connected to an external pipe, and the reaction tube outlet 103 is threadedly connected to an external pipe.

[0061] Another embodiment of the present invention provides a method for producing hydrogen by catalytic cracking of methane, using the reactor for producing hydrogen by catalytic cracking of methane as claimed in any one of claims 1 to 9, characterized in that it comprises the following steps:

[0062] S1. Before conducting the experiment of catalytic cracking of methane to produce hydrogen, the upper head 2, flange 13 and rectifying grid plate 9 of the reactor are first removed, a certain amount of catalyst is weighed and placed in the catalyst basket 4, and before filling, the cross baffle 402 at the bottom of the catalyst basket 4 needs to be covered with a stainless steel microporous square screen 403; the rectifying grid plate 9, the connector 12 and the upper head 2 at the upper end of the reactor tube 1 are fastened, and then the lower end of the reactor tube 1 is fastened with the lower head 3, and a thermocouple is inserted into its sleeve so that the top of the thermocouple is inside the catalyst basket 4, and then the reactor is selected and placed in the heating furnace, so that the catalyst basket 4 is located in the heating furnace, and the catalyst basket 4 is located in the middle of the heating section of the heating furnace, and then the experiment is started;

[0063] S2. First, introduce inert gas nitrogen to remove the air in tube 1, and heat the reactor at the same time, set the reduction temperature to 200°C-500°C, for example, 300°C, and the reduction pressure to normal pressure. When the reduction temperature of the catalyst is reached, cut off the nitrogen, introduce reducing gas hydrogen, with a volume flow rate of 100-500ml / min, and keep the temperature constant to reduce the catalyst;

[0064] S3. After the reduction is completed, the hydrogen valve is closed, and the temperature is rapidly raised under nitrogen purge until the gas chromatograph no longer detects hydrogen, and then 99% pure methane is introduced to start the reaction;

[0065] The specific experimental operating conditions in this step are: volume flow rate 100-500ml / min, reaction temperature 700℃, reaction pressure normal pressure. During the reaction, the gas product first enters the condenser to condense the heavy components in the product; then enters the drying tube to adsorb the moisture in the product. The volume flow of the dried gas product is measured by a wet flowmeter, and a part of the tail gas is introduced into the online gas chromatograph, and the rest of the tail gas is vented. Gas samples were taken from the gases at reaction times of 0.5h, 1.0h, 1.5h, and 2.0h for chromatographic analysis. The gas chromatograph is a 7890GC from Agilent, USA, with a TCD detector, a chromatographic column of 5A molecular sieve, and Ar gas as the carrier gas;

[0066] S4. After the experiment, take out the reactor from the heating furnace, disassemble the various components of the reactor in reverse order, take out the catalyst sample in the catalyst basket, and weigh it.

[0067] Test Example 1

[0068] This test example provides an online catalytic evaluation method for a methane catalytic cracking hydrogen production catalyst A, wherein the catalyst "A" is composed of 20% Ni and 80% magnesium aluminum spinel, and the preparation method is as follows:

[0069] (1) Solution preparation

[0070] 4.7 g of nickel nitrate, 2.6 g of magnesium nitrate, and 7.5 g of aluminum nitrate were dissolved in 450 ml of aqueous solution to form solution I, and 11 g of ammonium bicarbonate was prepared into 550 ml of aqueous solution to obtain solution II.

[0071] (2) Preparation of precipitate

[0072] Solution II was dripped into the strongly stirred solution I at a rate of about 120 ml / h to obtain precipitate III.

[0073] (3) Preparation of Catalyst

[0074] The obtained precipitate III was washed with deionized water and filtered, the filter cake was dried at 110°C for 6 hours, and calcined at 800°C for 8 hours in an air atmosphere to obtain a catalyst.

[0075] The reactor for producing hydrogen by catalytic cracking of methane provided by the present invention is used to carry out catalyst evaluation on the prepared catalyst.

[0076] Test Example 2

[0077] Catalyst "B" is composed of 20% Co and 80% magnesium aluminum spinel, the precipitant is ammonium bicarbonate, and the Co salt is cobalt nitrate. The preparation process of the catalyst is the same as that of "A".

[0078] Comparative Example 1

[0079] Catalyst "C" consists of 10% Ni and 90% MgO, and the precipitant is ammonium bicarbonate. The preparation process of the catalyst is the same as that of "A".

[0080] Table 1 Results of catalyst activity (methane conversion rate) of methane catalytic cracking to produce hydrogen measured in test examples and comparative examples

[0081]

[0082]

[0083] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A reactor for producing hydrogen by catalytic cracking of methane, characterized in that: include: A tube, an upper end cap connected to the upper end of the tube, and a lower end cap connected to the lower end of the tube; A catalyst basket is disposed in the tube; A support tube, wherein the support tube is a hollow structure with both ends being open ends, the upper open end of the support tube being connected to the bottom of the catalyst basket, and the lower open end of the support tube being pressed against the top of the lower head; Thermocouple sleeve, the thermocouple sleeve is inserted into the support tube, the upper end of the thermocouple sleeve extends into the catalyst basket along the upper opening end of the support tube, and the lower end of the thermocouple sleeve extends out of the lower end of the lower head.

2. The reactor for producing hydrogen by catalytic cracking of methane according to claim 1, characterized in that: An inner lining is provided near the upper end of the inner wall of the tube, and the bottom of the catalyst basket is pressed against the surface of the inner lining to fix the catalyst basket.

3. The reactor for producing hydrogen by catalytic cracking of methane according to claim 1, characterized in that: The catalyst basket is open, cylindrical in shape as a whole, and has a conical bottom.

4. The reactor for producing hydrogen by catalytic cracking of methane according to claim 3, characterized in that: The bottom of the catalyst basket is provided with an annular mounting groove and a cross baffle, and the cross baffle is covered with a mesh screen.

5. The reactor for producing hydrogen by catalytic cracking of methane according to claim 2, characterized in that: The lower end of the support tube is provided with an external thread, and a compression spring and a compression nut are arranged outside the support tube between the tube and the lower head to form tension so that the bottom of the catalyst basket is pressed against the tube and the liner, thereby fixing the catalyst basket.

6. The reactor for producing hydrogen by catalytic cracking of methane according to claim 1, characterized in that: A rectifying grid plate installation groove for installing a rectifying grid plate is arranged in the tube above the catalyst basket, and a sealing ring is arranged in the rectifying grid plate installation groove.

7. The reactor for producing hydrogen by catalytic cracking of methane according to claim 6, characterized in that: The rectifying grid plate is placed on the step surface where the circular inner cavity at the upper end of the tube and the working cavity meet; the holes inside the rectifying grid plate are evenly distributed along the axial direction of the tube.

8. The reactor for producing hydrogen by catalytic cracking of methane according to claim 1, characterized in that: The upper end of the tube is connected to the connecting piece by a flange, and the connecting piece is connected to the upper head.

9. The reactor for producing hydrogen by catalytic cracking of methane according to claim 1, characterized in that: A reaction tube inlet is arranged above the tube, and a reaction tube outlet is arranged on the side wall above the bottom end cap of the tube.

10. A method for producing hydrogen by catalytic cracking of methane, using the reactor for producing hydrogen by catalytic cracking of methane as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1. Before conducting the experiment of catalytic cracking of methane to produce hydrogen, the upper head, flange and rectifier grid plate of the reactor are first removed, a certain amount of catalyst is weighed and placed in the catalyst basket, and before filling, the cross baffle at the bottom of the catalyst basket needs to be covered with a stainless steel microporous square screen; the rectifier grid plate, connector and upper head at the upper end of the reactor tube are fastened, and then the lower end of the reactor tube is fastened with the lower head, and the thermocouple is inserted into its sleeve so that the top of the thermocouple is inside the catalyst basket, and then the reactor is selected and placed in the heating furnace, so that the catalyst basket is located in the heating furnace, and the catalyst basket is located in the middle of the heating section of the heating furnace, and then the experiment is started; S2. First, introduce inert gas nitrogen to remove the air in the tube, and heat the reactor at the same time, set the reduction temperature to 200°C-500°C, and the reduction pressure to normal pressure. When the reduction temperature of the catalyst is reached, cut off the nitrogen, introduce reducing gas hydrogen, and keep the temperature constant to reduce the catalyst; S3. After the reduction is completed, the hydrogen valve is closed, and the temperature is rapidly raised under nitrogen purge until the gas chromatograph no longer detects hydrogen, and then methane is introduced to start the reaction; S4. After the experiment, take out the reactor from the heating furnace, disassemble the various components of the reactor in reverse order, take out the catalyst sample in the catalyst basket, and weigh it.

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