A cleavage reactor

Abstract

The utility model discloses a cracking reactor, including reactor shell, feed pipe, first heating element and second heating element, the bottom of reactor shell is provided with the discharge port for discharging reactant and is used for discharging catalyst's unloading port, the bottom of feed pipe is connected with the bottom of reactor shell, and the bottom of feed pipe is provided with the feed port, the top of feed pipe and the top of reactor shell are provided with top space between, and the first heating element is arranged in the feed pipe, and the circumferential space between reactor shell and feed pipe is provided with second heating element, the utility model discloses a cracking reactor due to adopting mixed heating mode, on one hand, ammonia is heated to higher than catalyst active temperature in the heating resistance wire in the import center pipe, makes the gas into catalyst layer and produce ammonia cracking reaction, and the catalyst of gas inlet end is fully utilized, and catalyst utilization rate is high.

Description

Technical Field

[0001] This utility model relates to a pyrolysis reactor. Background Technology

[0002] In current domestic and international ammonia cracking hydrogen production reactors, the ammonia cracking reactors are mostly tubular reactors. The steel pipes (or furnace chamber) of the tubular reactor are filled with ammonia cracking catalyst and sealed. Gas inlet and outlet ports are located at both ends of the steel pipes containing the catalyst. Since ammonia cracking is an exothermic reaction, several steel pipes containing the cracking reactor are placed in a box equipped with electric heaters. Electric heating is used to supply heat to the ammonia cracking reaction inside the pipes through heat conduction and radiation. When the catalyst in this type of tubular cracking reactor reaches the end of its service life and cannot be used, the pipes must be cut to remove the spent catalyst. This destructive cutting makes it difficult to reuse the pipes; the reactor must be replaced. Furthermore, due to the inherent shape and characteristics of the tubular reactor, the maximum ammonia cracking production capacity of a single unit can only reach 160 kg / h, which is unsuitable for large-scale production. Utility Model Content

[0003] The purpose of this invention is to solve the problems of existing pyrolysis reactors, such as the inability to easily load and unload catalysts, the inability to reuse reactors, and the inability to conduct large-scale production, by providing a pyrolysis reactor. The pyrolysis reactor of this invention has a simple structure, high thermal energy utilization rate, and stable and controllable reaction temperature.

[0004] This utility model solves the above-mentioned technical problems through the following technical solutions:

[0005] This invention provides a pyrolysis reactor, which includes a reactor shell, a feed pipe, a first heating element, and a second heating element; the bottom of the reactor shell is provided with a discharge port for discharging reactants and a discharge port for discharging catalyst;

[0006] The bottom of the feed pipe is connected to the bottom of the reactor shell, and the bottom of the feed pipe is provided with a feed inlet; a top space is provided between the top of the feed pipe and the top of the reactor shell, and the first heating element is provided inside the feed pipe. The top space forms a buffer space for buffering the reaction raw materials that flow out of the feed pipe and are preheated by the first heating element.

[0007] The second heating element is provided in the circumferential space between the reactor shell and the feed pipe. The circumferential space is connected to the top space and is used to introduce the heated reaction raw materials into the circumferential space.

[0008] The entire circumferential space of the pyrolysis reactor of this invention can be used for packing catalyst, resulting in a large catalyst loading capacity and high production capacity. Furthermore, the pyrolysis reactor of this invention has high catalyst utilization: Firstly, ammonia gas is heated to above the catalyst activation temperature in the feed pipe, causing an ammonia pyrolysis reaction to occur as soon as the ammonia gas enters the catalyst bed, thus fully utilizing the catalyst at the gas inlet end; secondly, the second heating element in the catalyst bed region ensures that the reaction temperature in any area of ​​the catalyst bed reaches or exceeds the catalyst activation temperature, further maximizing the utilization of the catalyst within the reactor and improving the conversion rate of ammonia pyrolysis; thirdly, the buffer space formed at the top makes the ammonia gas entering the catalyst bed more evenly distributed, further enhancing catalyst utilization.

[0009] In this invention, the pyrolysis reactor preferably further includes a support frame, the second heating element is connected to the support frame, and the support frame is fixed to the feed pipe. This allows the second heating element to be stably supported in the catalyst bed.

[0010] The supporting frame can be a steel frame or a supporting plate.

[0011] In this invention, a plurality of second heating elements are preferably arranged concentrically around the feed pipe, with the projections of two adjacent rings of second heating elements on the feed pipe arranged evenly at intervals along the circumference of the feed pipe. This preferred embodiment can further improve the uniformity of heating.

[0012] In this invention, the second heating element preferably includes a second heating wire, a second terminal, and a protective tube. The second heating wire is disposed inside the protective tube. One end of the second terminal is connected to the second heating wire, and the other end of the second terminal is connected to the top of the reactor shell. The second terminal is used to connect to an external heating power supply. By providing a protective tube, wear and damage to the heating wire of the second heating element caused by direct contact with the catalyst can be further avoided.

[0013] When the aforementioned support frame is provided, the protective pipe is installed on the support frame.

[0014] In this invention, the first heating element includes a plurality of first heating wires and a first terminal. The plurality of first heating wires are arranged side by side. One end of the first terminal is connected to the first heating wire, and the other end of the first terminal is connected to the top of the reactor shell. The first terminal is used to connect to an external heating power supply.

[0015] Preferably, the two ends of the first heating wire are also provided with insulating sheets, such as mica insulating sheets. The insulating sheets are arranged perpendicular to the axis of the feed tube. A gas channel is provided between the insulating sheets and the inner wall of the feed tube to connect the feed tube and the top space.

[0016] In this invention, the feed pipe is located at the center of the reactor shell.

[0017] In this invention, a discharge pipe is preferably provided at the bottom of the reactor shell, and a discharge port is provided on the side of the discharge pipe. The discharge pipe is sleeved outside the feed pipe, and an annular channel is provided between the feed pipe and the discharge pipe, connecting the discharge port and the circumferential space. By setting the discharge pipe and the feed pipe as a sleeve structure, the number of openings on the reactor shell can be reduced, thereby reducing the impact on the strength of the bottom of the reactor shell.

[0018] In this invention, the pyrolysis reactor preferably further includes a heat insulation layer disposed on the inner wall of the reactor shell for heat preservation and to reduce heat loss.

[0019] In this invention, the reactor shell preferably includes a cylindrical body, a lower end cap, and a cover plate. The lower end cap and the cover plate are respectively connected to both ends of the cylindrical body. The cover plate is connected to the cylindrical body via a flange, facilitating catalyst loading. The lower end cap has an outwardly convex hemispherical structure, which aids in catalyst unloading. Preferably, the lower end cap is welded to the cylindrical body.

[0020] Preferably, there are at least two discharge ports, and the at least two discharge ports are symmetrically arranged around the axis of the reactor shell at the lower part of the lower head; when the feed pipe is located at the center of the reactor shell, the discharge ports are preferably arranged around the feed pipe to better realize the self-unloading of the catalyst.

[0021] In this invention, depending on the specific pyrolysis reaction, the circumferential space may also be filled with a catalyst bed; preferably, the circumferential space where the second heating element is located is also filled with a catalyst bed, the top of which is not higher than the top of the feed pipe. This prevents the catalyst from entering the feed pipe and affecting the feed.

[0022] The positive and progressive effects of this utility model are as follows:

[0023] (1) The catalyst loading of the cracking reactor of this utility model is large, the production capacity is large, and the production scale is controllable. When used for ammonia cracking to produce hydrogen, the production capacity of a single ammonia cracking unit can reach 500kg / h to 3750kg / h by adjusting the equipment specifications.

[0024] (2) The pyrolysis reactor of this utility model adopts a mixed heating method. On the one hand, the ammonia gas is heated to a temperature higher than the catalyst activation temperature by the heating resistance wire in the central inlet tube, so that the gas enters the catalyst bed and produces an ammonia pyrolysis reaction. The catalyst at the gas inlet end is fully utilized and the catalyst utilization rate is high. On the other hand, the catalyst bed is equipped with an electric heating element with a heating protection tube, which is evenly arranged in the catalyst bed so that the reaction temperature in any area of ​​the catalyst bed can reach or exceed the catalyst activation temperature, so that the catalyst in the reactor is fully utilized and the conversion rate of ammonia pyrolysis is improved.

[0025] (3) The pyrolysis reactor of this utility model has a buffer space, which makes the ammonia gas entering the catalyst bed more uniformly distributed, the catalyst utilization is high, and the ammonia pyrolysis conversion rate is high.

[0026] (4) The pyrolysis reactor of this utility model can be applied to different production scale requirements, has a simple equipment structure, a simple process flow, and the reaction temperature of the catalyst bed is easy to control, which facilitates safe and stable production management. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a pyrolysis reactor according to a preferred embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1-Reactor shell, 2-Feed pipe, 3-First heating element, 4-Second heating element, 5-Support frame, 6-Top space, 7-Circumferential space, 8-Insulation layer, 9-Discharge pipe;

[0030] 101-Discharge port, 102-Unloading port, 103-Cylinder body, 104-Lower end cap, 105-Cover plate;

[0031] 201 - Feed Inlet;

[0032] 301 - First heating wire, 302 - First terminal, 303 - Insulating sheet;

[0033] 401 - Second heating wire, 402 - Second terminal, 403 - Protective tube. Detailed Implementation

[0034] The present invention is further illustrated below by way of embodiments, but these embodiments do not limit the present invention to the scope of the embodiments described. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or as selected according to the product instructions.

[0035] One embodiment of this utility model discloses a pyrolysis reactor, such as Figure 1As shown, it includes a reactor shell 1, a feed pipe 2, a first heating element 3, a second heating element 4, and a support frame 5; the bottom of the reactor shell 1 is provided with a discharge port 101 for discharging reactants and a discharge port 102 for discharging catalyst.

[0036] The bottom of the feed pipe 2 is connected to the bottom of the reactor shell 1, and the bottom of the feed pipe 2 is provided with a feed inlet 201; a top space 6 is provided between the top of the feed pipe 2 and the top of the reactor shell 1, and a first heating element 3 is provided inside the feed pipe 2. The top space 6 forms a buffer space for the reaction raw materials that flow out of the feed pipe 2 and are preheated by the first heating element 3 to be buffered.

[0037] A second heating element 4 is installed in the circumferential space 7 between the reactor shell 1 and the feed pipe 2. The circumferential space 7 is connected to the top space 6 and is used to introduce heated reaction raw materials into the circumferential space 7. In this embodiment, the circumferential space 7 where the second heating element 4 is located is filled with a catalyst bed, and the top of the catalyst bed is not higher than the top of the feed pipe 2.

[0038] In this embodiment, the feed pipe 2 is located at the center of the reactor shell 1. The reactor shell 1 includes a cylindrical body 103, a lower end cap 104, and a cover plate 105. The lower end cap 104 and the cover plate 105 are respectively connected to both ends of the cylindrical body 103. The cover plate 105 is connected to the cylindrical body 103 via a flange. The lower end cap 104 is a convex hemispherical structure and is welded to the cylindrical body 103. There are two discharge ports 102, which are symmetrically arranged on the lower end cap 104 around the axis of the reactor shell 1, and the two discharge ports are located around the feed pipe 2.

[0039] In this embodiment, a heat insulation layer 8 is provided on the inner wall of the reactor shell 1.

[0040] In this embodiment, the second heating element 4 includes a second heating wire 401, a second terminal 402, and a protective tube 403. The second heating wire 401 is disposed inside the protective tube 403. One end of the second terminal 402 is connected to the second heating wire 401, and the other end of the second terminal 402 is connected to the top of the reactor shell 1. The second terminal 402 is used to connect to an external heating power supply. The protective tube 403 is connected to the support frame 5, and the support frame 5 is fixed to the feed pipe 2. The support frame 5 is a steel frame or a support plate.

[0041] In this embodiment, a plurality of second heating elements 4 are arranged in concentric circles with the feed pipe 2 as the center, and the projections of two adjacent rings of second heating elements 4 on the feed pipe 2 are arranged evenly and sequentially along the circumference of the feed pipe 2.

[0042] In this embodiment, the first heating element 3 includes a plurality of first heating wires 301 and a first terminal 302. The plurality of first heating wires 301 are arranged in parallel. One end of the first terminal 302 is connected to the first heating wire 301, and the other end of the first terminal 302 is connected to the top of the reactor shell 1. The first terminal 302 is used to connect to an external heating power supply. Insulating sheets 303, such as mica insulating sheets, are also provided at both ends of the first heating wires 301. The insulating sheets 303 are arranged perpendicular to the axis of the feed pipe 2. A gas channel is provided between the insulating sheets 303 and the inner wall of the feed pipe 2 to connect the feed pipe 2 and the top space 6.

[0043] In this embodiment, a discharge pipe 9 is provided at the bottom of the reactor shell 1, and a discharge port 101 is provided on the side of the discharge pipe 9. The discharge pipe 9 is sleeved outside the feed pipe 2. An annular channel is provided between the feed pipe 2 and the discharge pipe 9. The bottom of the annular channel is closed, and the annular channel connects the discharge port 101 and the circumferential space 7.

[0044] Example of effect:

[0045] The ammonia cracking to hydrogen production is carried out using the cracking reactor described in the above embodiments, and the specific process parameters are as follows:

[0046] Iron-based cracking catalyst A106 is packed into the space between the reactor shell 1 and the feed pipe 2. The parameters of the iron-based cracking catalyst A106 are as follows: total iron content 68-72%, iron ratio 0.55-0.65, particle shape φ1.5×3.3 m, and bulk density 2.5-3.5 g / cm³. 3 Compressive strength ≥50 N / cm.

[0047] Approximately 73.39 kmol / h of ammonia gas enters the feed pipe 2 and is heated by the first heating element 3 to a temperature approximately 60°C above the catalyst activation temperature. The heated ammonia gas then enters the buffer space. The ammonia gas is briefly buffered in the top space 6 before flowing uniformly downwards to the catalyst bed for ammonia cracking, producing nitrogen and hydrogen. As the cracking reaction progresses, the gas temperature in the catalyst bed decreases, and the gas is then heated by the second heating element 4 to continue the ammonia cracking reaction. Approximately 146.78 kmol / h of the resulting nitrogen and hydrogen mixture enters the annular channel between the feed pipe 2 and the discharge pipe 9, exiting the reactor shell 1 from the discharge port 101.

[0048] Calculations show that the ammonia cracking conversion rate is greater than 99.98%.

Claims

1. A pyrolysis reactor, characterized in that, It includes a reactor shell, a feed pipe, a first heating element, and a second heating element; the bottom of the reactor shell is provided with a discharge port for discharging reactants and a discharge port for discharging catalyst; The bottom of the feed pipe is connected to the bottom of the reactor shell, and the bottom of the feed pipe is provided with a feed inlet; a top space is provided between the top of the feed pipe and the top of the reactor shell, and the first heating element is provided inside the feed pipe. The top space forms a buffer space for buffering the reaction raw materials that flow out of the feed pipe and are preheated by the first heating element. The second heating element is provided in the circumferential space between the reactor shell and the feed pipe. The circumferential space is connected to the top space and is used to introduce the heated reaction raw materials into the circumferential space.

2. The pyrolysis reactor as described in claim 1, characterized in that, The pyrolysis reactor also includes a support frame, the second heating element is connected to the support frame, and the support frame is fixed to the feed pipe.

3. The pyrolysis reactor as described in claim 1 or 2, characterized in that, A number of second heating elements are arranged in concentric circles around the feed pipe, and the projections of two adjacent circles of second heating elements on the feed pipe are arranged at uniform intervals along the circumference of the feed pipe. And / or, the second heating element includes a second heating wire, a second terminal and a protective tube, the second heating wire is disposed inside the protective tube, one end of the second terminal is connected to the second heating wire, and the other end of the second terminal is connected to the top of the reactor shell.

4. The pyrolysis reactor as described in claim 1, characterized in that, The first heating element includes a plurality of first heating wires and a first terminal. The plurality of first heating wires are arranged in parallel. One end of the first terminal is connected to the first heating wire, and the other end of the first terminal is connected to the top of the reactor shell. Insulating sheets are provided at both ends of the first heating wire. The insulating sheets are arranged perpendicular to the axis of the feed tube. A gas channel is provided between the insulating sheets and the inner wall of the feed tube to connect the feed tube and the top space.

5. The pyrolysis reactor as described in claim 1, characterized in that, The feed pipe is located at the center of the reactor shell.

6. The pyrolysis reactor as described in claim 1, characterized in that, The bottom of the reactor shell is provided with a discharge pipe, and the side of the discharge pipe is provided with a discharge port. The discharge pipe is sleeved outside the feed pipe. An annular channel is provided between the feed pipe and the discharge pipe, and the annular channel connects the discharge port and the circumferential space.

7. The pyrolysis reactor as described in claim 1, characterized in that, The pyrolysis reactor also includes a heat insulation layer disposed on the inner wall of the reactor shell.

8. The pyrolysis reactor as described in claim 1, characterized in that, The reactor shell includes a cylindrical body, a lower end cap, and a cover plate. The lower end cap and the cover plate are respectively connected to both ends of the cylindrical body. The cover plate is connected to the cylindrical body via a flange. The lower end cap is a convex hemispherical structure.

9. The pyrolysis reactor as described in claim 8, characterized in that, There are at least two discharge ports, and the at least two discharge ports are symmetrically arranged around the axis of the reactor shell at the lower part of the lower head.

10. The pyrolysis reactor as claimed in claim 1, characterized in that, The circumferential space where the second heating element is located is also filled with a catalyst bed, the top of which is not higher than the top of the feed pipe.

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