Vertical ammonia converter electric heater and gas heating method

Abstract

The application provides a vertical ammonia synthesis tower electric heater, which comprises a shell and an inner part, the shell comprises, from bottom to top, an outlet flange, a lower tee joint, an inlet flange, a lower end part of a cylinder, the cylinder, an upper end part of the cylinder and a flat cover, and the flat cover is provided with an opening for inserting an electric furnace wire; the inner part comprises, from bottom to top, a lower pressing ring, a lower packing, a lower fixing clamp, a lower connecting pipe, a lower support, an upper support, an upper connecting pipe, an upper fixing clamp, an upper packing and an upper pressing ring, and the side walls of the lower support and the upper connecting pipe are provided with through holes. The vertical ammonia synthesis tower electric heater has a vertical single-inlet single-outlet structure, has a small floor area and a high heating speed, and is suitable for small and medium-sized ammonia plants.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ammonia synthesis, and more particularly to a vertical ammonia synthesis tower electric heater and a gas heating method. BACKGROUND

[0002] In the national economy, ammonia occupies an important position, especially for agricultural production has a great significance. Ammonia is also a very important industrial raw material, in chemical fiber, plastic industry, with ammonia, nitric acid and urea as the source of nitrogen production caprolactam, nylon and other products. Ammonia is also widely used in other industries. In the petroleum refining, rubber industry, metallurgical industry and mechanical processing and other departments, as well as light industry, food, pharmaceutical industry department, ammonia and its processing products are indispensable.

[0003] Hydrogen and nitrogen are combined into ammonia under high temperature and high pressure and under the action of catalyst. The ammonia synthesis tower is the heart of the ammonia synthesis plant, and the electric heater is the most important auxiliary equipment of the ammonia synthesis tower. When the ammonia synthesis tower is started, the electric heater needs to provide heat source for the catalyst reduction of the synthesis tower, and the electric heater is also applied to the temperature rise after the ammonia synthesis tower is stopped or the treatment after the accident. The electric heater is provided outside the synthesis tower, which has the advantages of simple structure, safety and reliability, convenient manufacturing, installation and maintenance, and has been widely applied.

[0004] The conventional ammonia synthesis tower electric heater adopts a double-in double-out structure, which has large flow and is suitable for large ammonia synthesis towers, but is not suitable for small and medium-sized ammonia synthesis towers. Therefore, how to provide an electric heater suitable for small and medium-sized ammonia plants is an urgent problem to be solved by those skilled in the art. SUMMARY

[0005] Therefore, the present application provides a vertical ammonia synthesis tower electric heater, which has a single-in single-out vertical heating structure and is suitable for small and medium-sized ammonia plants.

[0006] To achieve the above purpose, the application provides a vertical ammonia synthesis tower electric heater, which comprises a shell and an inner part, the shell comprises, from bottom to top, an outlet flange, a lower tee joint, an inlet flange, a lower end of a cylinder, the cylinder, an upper end of the cylinder and a flat cover, wherein the lower tee joint is sealingly connected with the outlet flange, the inlet flange and the lower end of the cylinder, the upper end of the cylinder is sealingly connected with the flat cover, the cylinder is fixedly connected with the lower end of the cylinder and the upper end of the cylinder through welding, and the flat cover is provided with an opening for inserting an electric furnace wire; the inner part comprises, from bottom to top, a lower pressing ring, a lower packing, a lower fixing clamp, a lower connecting pipe, a lower support, an upper support, an upper connecting pipe, an upper fixing clamp, an upper packing and an upper pressing ring, wherein the lower pressing ring is fixedly connected with the lower fixing clamp through bolts, the lower packing is arranged on the outer periphery of the lower fixing clamp close to the lower pressing ring, the upper pressing ring is fixedly connected with the upper fixing clamp through bolts, the upper packing is arranged on the outer periphery of the upper fixing clamp close to the upper pressing ring, the lower fixing clamp is fixedly connected with the lower connecting pipe through welding, the lower connecting pipe and the lower support are fixedly connected with the upper support through welding, the lower support is located on the outer periphery of the upper end of the lower connecting pipe, the upper support is fixedly connected with the upper connecting pipe through welding, and the upper connecting pipe is fixedly connected with the upper fixing clamp through welding, and the side walls of the lower support and the upper connecting pipe are both provided with through holes.

[0007] Optionally, the lower tee joint is sealingly connected with the outlet flange and the inlet flange through studs, nuts and omega-shaped sealing rings, and the upper end of the cylinder is sealingly connected with the flat cover through studs, nuts and omega-shaped sealing rings; the lower tee joint is sealingly connected with the lower end of the cylinder through studs, nuts and octagonal pads.

[0008] Optionally, the outer periphery of the cylinder is welded with a rigid ring lug seat and a lifting lug, and the side of the flat cover and the lower tee joint is provided with a lifting ring screw.

[0009] Optionally, the side wall of the lower support is provided with four through holes which are circumferentially and uniformly distributed, and the side wall of the upper connecting pipe is provided with 12 rows of through holes which are circumferentially and uniformly distributed and total 288.

[0010] Optionally, the bottom outer periphery of the lower support and the top inner side of the lower end of the cylinder are provided with matching inclined surfaces.

[0011] Optionally, the lower outer periphery of the upper connecting pipe is provided with a heat preservation sleeve, one end of the heat preservation sleeve is welded to the upper support, the other end of the heat preservation sleeve is welded to the upper connecting pipe through a heat preservation fixing block, and the heat preservation sleeve and the upper connecting pipe are filled with a heat preservation material.

[0012] Optionally, the top of the upper fixing clamp is welded with a lifting lug, and the upper connecting pipe and the upper fixing clamp are further welded with a support rib plate.

[0013] Optionally, the upper connecting pipe is further provided with a stirring device.

[0014] Optionally, the inner walls of the upper connecting pipe and the lower connecting pipe are further coated with a heat preservation coating.

[0015] The application also provides a method for heating gas by using the vertical ammonia synthesis tower electric heater, which comprises the following steps: feeding the gas to be heated into the gap between the shell and the inner part through the cold gas inlet formed by the lower tee joint and the inlet flange, allowing the gas to rise in the gap between the shell and the inner part and enter the gap between the cylinder and the upper connecting pipe from the gap between the lower tee joint and the lower connecting pipe through the through hole of the lower support, then entering the inside of the upper connecting pipe through the through hole of the upper connecting pipe, allowing the gas to flow downward after being heated by the electric furnace wire inserted through the electric furnace wire hole on the flat cover, and allowing the heated gas to flow out of the hot gas outlet formed by the lower tee joint and the outlet flange through the lower connecting pipe.

[0016] Compared with the prior art, the vertical ammonia synthesis tower electric heater provided by the application has the following beneficial effects:

[0017] (1) Compared with the large-flow electric heater with a double-inlet and double-outlet structure in the prior art, the vertical ammonia synthesis tower electric heater provided by the application has a vertical single-inlet and single-outlet structure. The mixed gas before reaction can enter the gap between the shell and the inner part through the cold gas inlet on the side of the lower tee joint, rise along the gap and enter the inside of the inner part through the through hole of the upper connecting pipe, flow downward after being heated by the electric furnace wire inserted through the flat cover and then flow out of the hot gas outlet at the bottom of the lower tee joint. The vertical single-inlet and single-outlet structure has a small footprint and a fast heating speed, and is suitable for small and medium-sized ammonia plants.

[0018] (2) In terms of sealing structure, the vertical ammonia synthesis tower electric heater provided by the application adopts a threaded fixing mode with an omega-shaped sealing ring at the cold gas inlet, the hot gas outlet and the flat cover part, has simple assembly, good sealing performance and is not easily affected by changes in pressure and temperature, and adopts a threaded fixing mode with an octagonal gasket between the lower end of the cylinder and the lower tee joint, so that the inner part and the shell can be easily disassembled and assembled for inspection.

[0019] (3) In terms of heat preservation, the vertical ammonia synthesis tower electric heater provided by the application is provided with a heat preservation sleeve at the lower outer periphery of the upper connecting pipe through which the mixed gas flows immediately after being heated, and the heat preservation sleeve is filled with heat preservation material between the heat preservation sleeve and the upper connecting pipe, so that the mixed gas is not easy to release heat to the surrounding medium after being heated, but carries the heat and flows out of the hot gas outlet at a high temperature. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the application, the embodiments of the application will be further described and illustrated with reference to the following drawings, which are only used to more conveniently and specifically describe the embodiments of the application and are not a limitation on the application.

[0021] Figure 1is a schematic diagram of the overall structure of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0022] Figure 2 is a schematic diagram of the internal structure of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0023] Figure 3 is a schematic diagram of the flat cover structure of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0024] Figure 4 is a schematic diagram of the connection structure of a lower compression ring, lower packing, and lower fixed clamp of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0025] Figure 5 is a schematic diagram of the connection structure of an upper compression ring, upper packing, and upper fixed clamp of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0026] Figure 6 is a schematic diagram of the connection structure of an inlet flange, omega-shaped sealing ring, and lower tee of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0027] Figure 7 is a schematic diagram of the connection structure of a lower tee, octagonal packing, and lower end of a cylinder of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0028] Figure 8 is a schematic diagram of the connection structure of an upper end of a cylinder, omega-shaped sealing ring, and flat cover of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0029] Figure 9 is a schematic diagram of the cross-section of a lower support of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application;

[0030] Figure 10 is a schematic diagram of the cross-section of an upper connection pipe of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application; and

[0031] Figure 11 is a schematic diagram of the connection structure of an upper connection pipe, heat-insulating sleeve, and heat-insulating fixed block of an electric heater for a vertical ammonia synthesis tower according to an example embodiment of the present application.

[0032] In the figure: 1 is an outlet flange, 2 is a lower tee joint, 3 is an inlet flange, 4 is a lower end of a cylinder, 5 is a cylinder, 6 is an upper end of the cylinder, 7 is a flat cover, 8 is a lower pressing ring, 9 is a lower packing, 10 is a lower fixing clamp, 11 is a lower connecting pipe, 12 is a lower support, 13 is an upper support, 14 is an upper connecting pipe, 15 is an upper fixing clamp, 16 is an upper packing, 17 is an upper pressing ring, 18 is an omega-shaped sealing ring, 19 is an octagonal gasket, 20 is a rigid ring lug seat, 21 is a lifting lug, 22 is a lifting ring screw, 23 is a heat preservation sleeve, 24 is a heat preservation fixing block, 25 is a heat preservation material, and 26 is a support rib plate; N1 is a cold gas inlet, N2 is a hot gas outlet, and e1-e3 are electric furnace wire ports. DETAILED DESCRIPTION

[0033] The vertical ammonia synthesis tower electric heater has a vertical single-inlet single-outlet structure, small footprint, and fast heating speed, and is suitable for small and medium-sized ammonia plants.

[0034] In one preferred embodiment of the present application, a vertical ammonia synthesis tower electric heater is provided, which comprises a shell and an inner part, for example, referring to Figures 1-5 . Figure 1 is a schematic diagram of the overall structure of the vertical ammonia synthesis tower electric heater according to an example embodiment of the present application, as shown in Figure 1 , the shell comprises, from bottom to top, an outlet flange 1, a lower tee joint 2, an inlet flange 3, a lower end of a cylinder 4, a cylinder 5, an upper end of the cylinder 6, and a flat cover 7, wherein the lower tee joint 2 is sealingly connected with the outlet flange 1, the inlet flange 3, and the lower end of the cylinder 4, the upper end of the cylinder 6 is sealingly connected with the flat cover 7, the cylinder 5 is fixedly connected with the lower end of the cylinder 4 and the upper end of the cylinder 6 by welding, and the flat cover 7 is provided with an opening for inserting an electric furnace wire. The structure of the flat cover 7 can refer to Figure 3 , Figure 3 is a schematic diagram of the flat cover structure of the vertical ammonia synthesis tower electric heater according to an example embodiment of the present application, as shown in Figure 3 , the top center part of the flat cover 7 is provided with three electric furnace wire ports e1-e3 for inserting electric furnace wires for heating; and the top peripheral part of the flat cover 7 is provided with a plurality of holes for inserting bolts, so that the bolts are inserted and nuts are added to realize the sealing connection between the flat cover and the upper end of the cylinder. Figure 2 is a schematic diagram of the inner part structure of the vertical ammonia synthesis tower electric heater according to an example embodiment of the present application, as shown in Figure 2As shown, the inner part comprises, from bottom to top, a lower pressing ring 8, a lower packing 9, a lower fixing clamp 10, a lower connecting pipe 11, a lower support 12, an upper support 13, an upper connecting pipe 14, an upper fixing clamp 15, an upper packing 16 and an upper pressing ring 17. The lower pressing ring 8 is fixedly connected with the lower fixing clamp 9 by bolts, the lower packing 9 is arranged on the outer periphery of the lower fixing clamp 10 close to the lower pressing ring 8, the upper pressing ring 17 is fixedly connected with the upper fixing clamp 15 by bolts, the upper packing 16 is arranged on the outer periphery of the upper fixing clamp 15 close to the upper pressing ring 17, the lower fixing clamp 10 is fixedly connected with the lower connecting pipe 11 by welding, the lower connecting pipe 11 and the lower support 12 are fixedly connected with the upper support 13 by welding, the lower support 12 is located on the upper end periphery of the lower connecting pipe 11, the upper support 13 is fixedly connected with the upper connecting pipe 14 by welding, the upper connecting pipe 14 is fixedly connected with the upper fixing clamp 15 by welding, and the side walls of the lower support 12 and the upper connecting pipe 14 are both provided with through holes. The connection structure between the lower pressing ring 8, the lower packing 9 and the lower fixing clamp 10 can refer to Figure 4 , Figure 4 The connection structure between the lower pressing ring 8, the lower packing 9 and the lower fixing clamp 10 is shown in Fig. 1, wherein the lower pressing ring 8 is fixedly connected with the lower fixing clamp 10 by bolts, and the lower fixing clamp 10 is provided with the lower packing 9 on the outer periphery close to the lower pressing ring 8. When the bolts are gradually tightened, the lower packing 9 is deformed and fills the gap between the lower fixing clamp 10 and the lower three-way pipe 2, thereby realizing the sealing between the shell and the inner part. The connection structure between the upper pressing ring 17, the upper packing 16 and the upper fixing clamp 15 can refer to Figure 5 , which has a similar fixing and sealing structure with the lower pressing ring 8, the lower packing 9 and the lower fixing clamp 10.

[0035] The working principle of the vertical ammonia synthesis tower electric heater provided by the present application will be described with reference to Figure 1 The mixed gas required for ammonia synthesis reaction is sent into the gap between the shell and the inner part through the cold gas inlet N1 formed by the inlet flange 3 and the lower three-way pipe 2, the mixed gas rises along the gap and enters into the gap between the cylinder 5 and the upper connecting pipe 14 from the gap between the lower three-way pipe 2 and the lower connecting pipe 11 through the through hole of the lower support 12, and then enters into the inside of the upper connecting pipe 14 through the through hole of the upper connecting pipe 14. The mixed gas flows downward after being heated by the electric furnace filaments inserted through the electric furnace filament ports e1-e3 on the flat cover 7, thereby flowing out from the hot gas outlet N2 formed by the lower three-way pipe 2 and the outlet flange 1 through the lower connecting pipe 11. The ammonia synthesis tower electric heater provided by the present application has a vertical structure with single inlet and single outlet, the mixed gas to be reacted can flow in from a single inlet and flow out from a single outlet close to the inlet position after being heated, the structure is simple and occupies small space, and is suitable for use as an ammonia synthesis tower electric heater for a small and medium-sized ammonia plant.

[0036] In a preferred embodiment of the present application, the lower tee joint 2 is connected to the outlet flange 1 and the inlet flange 3, and the upper end of the cylinder 6 is connected to the flat cover 7, by means of studs, nuts and omega-shaped sealing rings 18; the lower tee joint 2 is connected to the lower end of the cylinder 4 by means of studs, nuts and octagonal gaskets 19. That is, the vertical ammonia synthesis tower electric heater provided by the present application adopts a threaded fixing mode with omega-shaped sealing rings 18 at the connection part of the cold gas inlet N1, the connection part of the hot gas outlet N2 and the connection part of the flat cover 7 and the upper end of the cylinder 6. These connection parts are connected between pipes and are rarely disassembled after assembly, so the threaded fixing mode with omega-shaped sealing rings 18 is adopted, which is simple to install but complex to disassemble, has good sealing performance and is not easily affected by changes in pressure and temperature. The threaded fixing mode with octagonal gaskets 19 is adopted between the lower end of the cylinder 4 and the lower tee joint 2. The octagonal gaskets 19 are simple in structure and easy to disassemble and assemble, which is convenient for maintenance personnel to inspect the inner parts and the shell at any time. The connection structure between the inlet flange 3, the omega-shaped sealing ring 18 and the lower tee joint 2 can be referred to Figure 6 ; the connection structure between the lower tee joint 2, the octagonal gasket 19 and the lower end of the cylinder 4 can be referred to Figure 7 ; the connection structure between the upper end of the cylinder 6, the omega-shaped sealing ring 18 and the flat cover 7 can be referred to Figure 8 ; the connection structure between the inlet flange 1 and the lower tee joint 2 is similar to the connection structure between the outlet flange 3 and the lower tee joint 2, and can also be referred to Figure 6 .

[0037] In a preferred embodiment of the present application, rigid lug seats 20 and lifting lugs 21 are welded to the outer periphery of the cylinder 5. As shown in Figure 1 , the rigid lug seats 20 and the lifting lugs 21 can be welded to appropriate positions on the outer periphery of the cylinder 5. The rigid lug seats 20 can be used to bear the weight of the entire device and tangential forces and local stresses caused by eccentricity of the device or thermal expansion of the pipes, etc. The lifting lugs can be used to lift the shell before the inner parts are installed and to lift the entire device after the inner parts are installed. In a preferred embodiment of the present application, the side of the flat cover 7 and the side of the lower tee joint 2 are each provided with a lifting eye screw 22. As shown in Figure 1 , the side of the flat cover 7 and the side of the lower tee joint 2 are each provided with a threaded hole for screwing in the lifting eye screw 22. During assembly of the entire device or during separate transportation of the device components, the corresponding component can be lifted by screwing in the lifting eye screw 22 in the threaded hole. The threaded hole can be provided at an optional position on the side of the flat cover 7, and is preferably provided on the side opposite the cold gas inlet N1 on the side of the lower tee joint 2.

[0038] In a preferred embodiment of the present application, the side wall of the lower support 12 is provided with 4 circumferentially distributed through holes, and the side wall of the upper connecting pipe 14 is provided with 12 rows of a total of 288 circumferentially distributed through holes, for example, as shown in Figure 9 and Figure 10 . Figure 9is a cross-sectional view of a lower support of an electric heater for a vertical ammonia converter according to an example embodiment of the present application, as shown in Figure 9 As shown, the side wall of the lower support 12 is provided with four circumferentially distributed through-holes, which are used to allow the mixed gas from the cold gas inlet N1 to enter the gap between the lower three-way pipe 2 and the lower connecting pipe 11 and then enter the gap between the cylinder 5 and the upper connecting pipe 14. Figure 10 is a cross-sectional view of an upper connecting pipe of an electric heater for a vertical ammonia converter according to an example embodiment of the present application, as shown in Figure 10 As shown, the side wall of the upper connecting pipe 14 is provided with 12 rows of circumferentially distributed through-holes, with a total of 288 through-holes, and each row has 24 through-holes. The densely distributed through-holes not only allow the mixed gas to enter the inside of the upper connecting pipe 14 from the gap between the upper connecting pipe 14 and the cylinder 5, but also help the mixed gas to be more uniformly mixed and heated. It should be understood by those skilled in the art that when the pipe diameter and length are different, any appropriate number of through-holes can be provided at appropriate positions of the upper connecting pipe 14.

[0039] In a preferred embodiment of the present application, the bottom outer periphery of the lower support 12 and the top inner side of the lower end portion 4 of the cylinder are provided with matching inclined surfaces. As shown in Figure 1 and Figure 2 After the components of the inner part and the components of the shell are respectively assembled, the inner part needs to be placed inside the shell. The inclined surfaces of the bottom outer periphery of the lower support 12 and the top inner side of the lower end portion 4 of the cylinder allow the inner part to be stably placed inside the shell. It should be noted that no sealing structure is required here because the inclined surfaces are located exactly between the lower connecting pipe 11 and the lower three-way pipe 2. A small amount of mixed gas that penetrates the gap between the inclined surfaces will not leak out or enter the inside of the lower connecting pipe 11 in advance, but will flow upward along the gap between the inner part and the shell along with the gas passing through the through-holes of the lower support 12.

[0040] In a preferred embodiment of the present application, the lower outer periphery of the upper connecting pipe 14 is provided with a heat preservation sleeve 23. For example, as shown in Figure 2 and Figure 11 , Figure 2 is a schematic view of the structure of an inner part of an electric heater for a vertical ammonia converter according to an example embodiment of the present application, Figure 11 is a schematic view of the connection structure of an upper connecting pipe, a heat preservation sleeve, and a heat preservation fixing block of an electric heater for a vertical ammonia converter according to an example embodiment of the present application. As shown in Figure 2 and Figure 11As shown, one end of the heat-insulating sleeve 23 is welded to the upper support 13, and the other end of the heat-insulating sleeve 23 is welded to the upper connecting pipe 14 through the heat-insulating fixing block 24. The heat-insulating sleeve 23 is filled with heat-insulating material 25 between the heat-insulating sleeve 23 and the upper connecting pipe 14. The heat-insulating layer formed by the heat-insulating material 25 between the heat-insulating sleeve 23 and the upper connecting pipe 14 makes the heated mixed gas less likely to release heat to the pipe wall of the upper connecting pipe 14, thereby further increasing the heating efficiency. The heat-insulating material 25 can use any material known in the art, such as glass fiber with good insulation, high heat resistance, good corrosion resistance, and high mechanical strength. It should be noted that the heat-insulating sleeve 23 should not cover or block the through hole formed in the upper part of the upper connecting pipe 14, so as not to block the flow of the mixed gas.

[0041] In a preferred embodiment of the present application, a lifting lug is welded to the top of the upper fixing clamp 15, and a support rib plate 26 is also welded between the upper connecting pipe 14 and the upper fixing clamp 15. As shown, Figure 2 The lifting lug is used to lift the entire inner part for assembling the inner part into the shell; the support rib plate 26 is used to further reinforce the connection between the upper fixing clamp 15 and the upper connecting pipe 14 to prevent the upper fixing clamp 15 and the upper connecting pipe 14 from falling off when being lifted.

[0042] In a preferred embodiment of the present application, a stirring device is also provided in the upper connecting pipe 14, which is used to make the mixed gas more uniform. For example, the stirring device can be arranged inside the lower part of the upper connecting pipe 14 where the through hole is formed, so that the mixed gas can be further mixed after being heated, and the stirring device can also rebound part of the gas upward to be heated again, thereby improving the heating efficiency. Alternatively or additionally, the electric furnace wire can also have a stirring function, or the stirring device can be inserted into the upper connecting pipe through the electric furnace wire ports e1-e3 together with the electric furnace wire, so as to stir while heating.

[0043] In a preferred embodiment of the present application, the inner walls of the upper connecting pipe 14 and the lower connecting pipe 11 are also coated with a heat-insulating coating. The heat-insulating coating makes the heated mixed gas less likely to release heat to the outside of the upper connecting pipe 14 and the lower connecting pipe 11, thereby improving the utilization rate of heat.

[0044] In a preferred embodiment of the present application, a method for heating gas using the vertical ammonia synthesis tower electric heater described above is also provided, for example, referring to Figure 1 and Figure 2The method comprises: sending the gas to be heated into the gap between the shell and the inner part through the cold gas inlet N1 formed by the lower three-way joint 2 and the inlet flange 3, the gas rising in the gap between the shell and the inner part and entering the gap between the cylinder 5 and the upper connecting pipe 14 from the gap between the lower three-way joint 2 and the lower connecting pipe 11 through the through hole of the lower support 12, then entering the inside of the upper connecting pipe 14 through the through hole of the upper connecting pipe 14, at which the gas flows downward after being heated by the electric furnace wires inserted through the electric furnace wire ports e1-e3 on the flat cover 7, and the heated gas flows out from the hot gas outlet N2 formed by the lower three-way joint 2 and the outlet flange 1 through the lower connecting pipe 11.

[0045] It should be understood that the devices and / or structures in each of the embodiments provided in the present application can be combined, modified and / or changed to form new technical solutions. These technical solutions should also be included in the scope of protection claimed by the present application without creative labor.

[0046] A large number of specific examples are provided in the embodiments provided herein, and it should be understood that these examples are only for detailed description of the embodiments of the present application and are not limitations of the present application. The embodiments in the present application can be practiced without these specific examples. In some embodiments, the structures and / or techniques well known to those skilled in the art are not shown in detail, so as not to obscure the understanding of the present application.

[0047] Although the preferred embodiments of the present application have been shown and described herein, it will be readily apparent to those skilled in the art that these embodiments are provided only by way of example. Those skilled in the art will now be able to devise various changes, modifications and alternatives without departing from the present application. It should be understood that various alternatives to the embodiments of the present application described herein are optionally used to practice the present application. It is intended to define the scope of the present application by the claims and to encompass devices, structures and equivalents thereof within the scope of these claims.

Claims

1. A vertical ammonia synthesis column electric heater comprising a shell and an inner part, characterized in that, the shell comprises, from bottom to top, an outlet flange (1), a lower tee joint (2), an inlet flange (3), a lower end part of cylinder (4), a cylinder (5), an upper end part of cylinder (6) and a flat cover (7), wherein the lower tee joint (2) is sealingly connected with the outlet flange (1), the inlet flange (3) and the lower end part of cylinder (4), the upper end part of cylinder (6) is sealingly connected with the flat cover (7), the cylinder (5) is fixedly connected with the lower end part of cylinder (4) and the upper end part of cylinder (6) by welding, and the flat cover (7) is provided with an opening for inserting an electric furnace wire; the inner part comprises, from bottom to top, a lower pressing ring (8), a lower packing (9), a lower fixing clamp (10), a lower connecting pipe (11), a lower support (12), an upper support (13), an upper connecting pipe (14), an upper fixing clamp (15), an upper packing (16) and an upper pressing ring (17), wherein the lower pressing ring (8) is fixedly connected with the lower fixing clamp (10) by bolts, the lower packing (9) is arranged on the outer periphery of the lower fixing clamp (10) close to the lower pressing ring (8), the upper pressing ring (17) is fixedly connected with the upper fixing clamp (15) by bolts, the upper packing (16) is arranged on the outer periphery of the upper fixing clamp (15) close to the upper pressing ring (17), the lower fixing clamp (10) is fixedly connected with the lower connecting pipe (11) by welding, the lower connecting pipe (11) and the lower support (12) are fixedly connected with the upper support (13) by welding, the lower support (12) is located on the upper end periphery of the lower connecting pipe (11), the upper support (13) is fixedly connected with the upper connecting pipe (14) by welding, the upper connecting pipe (14) is fixedly connected with the upper fixing clamp (15) by welding, the side walls of the lower support (12) and the upper connecting pipe (14) are both provided with through holes, a stirring device is arranged in the upper connecting pipe (14), and the stirring device is arranged on the inner side below the part of the upper connecting pipe (14) provided with the through holes; the bottom periphery of the lower support (12) and the top inner side of the lower end part of cylinder (4) are provided with matching inclined surfaces; the sealing connection between the lower tee joint (2) and the outlet flange (1), the inlet flange (3) and the flat cover (7) is achieved by studs, nuts and Ω-shaped sealing rings (18); the sealing connection between the lower tee joint (2) and the lower end part of cylinder (4) is achieved by studs, nuts and octagonal gaskets (19); a heat preservation sleeve (23) is arranged on the lower periphery of the upper connecting pipe (14), one end of the heat preservation sleeve (23) is welded to the upper support (13), the other end of the heat preservation sleeve (23) is welded to the upper connecting pipe (14) through a heat preservation fixing block (24), and the heat preservation sleeve (23) is filled with heat preservation material (25) between the heat preservation sleeve (23) and the upper connecting pipe (14).

2. The vertical ammonia synthesis tower electric heater according to claim 1, characterized in that, a rigid ring lug seat (20) and a lifting lug (21) are welded on the outer periphery of the cylinder (5), and a lifting ring screw (22) is arranged on the side of the flat cover (7) and the lower tee joint (2).

3. The vertical ammonia synthesis tower electric heater according to claim 1, characterized in that, four circumferentially distributed through holes are arranged in the side wall of the lower support (12), and 12 rows of 288 circumferentially distributed through holes are arranged in the side wall of the upper connecting pipe (14).

4. The vertical ammonia synthesis tower electric heater according to claim 1, characterized in that, a lifting lug is welded on the top of the upper fixing clamp (15), and a support rib plate (26) is further welded between the upper connecting pipe (14) and the upper fixing clamp (15).

5. The vertical ammonia synthesis tower electric heater according to claim 1, characterized in that, the inner walls of the upper connecting pipe (14) and the lower connecting pipe (11) are further coated with a heat preservation coating.

6. A method for heating a gas with the electric heater for a vertical ammonia synthesis converter according to any one of claims 1 to 5, characterized in that, The method comprises: the gas to be heated is sent into the gap between the shell and the inner part through the cold gas inlet (N1) formed by the inlet flange (3) and the lower tee joint (2), the gas rises in the gap between the shell and the inner part and enters the gap between the cylinder (5) and the upper connecting pipe (14) through the through holes of the lower support (12) from the gap between the lower tee joint (2) and the lower connecting pipe (11), and then enters the inside of the upper connecting pipe (14) through the through holes of the upper connecting pipe (14), at which the gas is heated by the electric furnace wire inserted through the electric furnace wire ports (e1-3) on the flat cover (7) and then flows downward, the heated gas flows out of the hot gas outlet (N2) formed by the lower tee joint (2) and the outlet flange (1) through the lower connecting pipe (11).

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