A radial flow ammonia synthesis reactor diffusing from inside to outside

Abstract

The application relates to a radial flow synthesis ammonia reaction tower of inside-out diffusion type, which comprises a closed cylindrical shell with a top head; at least one partition plate is arranged in the shell to divide the shell into at least two independent reaction cavities; a catalyst layer is arranged in the reaction cavities and is separated from the inner wall of the reaction cavities on the outer side wall and the top surface; a heat exchange groove is arranged in the catalyst layer, the upper end of the heat exchange groove is connected with the upper end of the catalyst layer, the lower end of the heat exchange groove is suspended, and the side wall of the heat exchange groove is separated from the inner side wall of the catalyst layer; a heat exchange pipe is arranged in the heat exchange groove along the longitudinal direction of the shell; an air outlet pipe is arranged in the heat exchange groove, the upper end of the air outlet pipe is connected with the air outlet hole, and the lower end of the air outlet pipe is suspended; and an exhaust pipe is arranged, the lower end of the exhaust pipe is connected with the air outlet hole of the top plate of the shell, and the upper end of the exhaust pipe extends out of the top head. The application can prolong the residence time of reaction gas in the catalyst layer.

Description

Technical Field

[0001] This invention relates to chemical equipment, and more particularly to an ammonia synthesis device, specifically an ammonia synthesis reaction tower with an inward-outward diffusion radial flow. Background Technology

[0002] Ammonia is an indispensable raw material in many chemical production fields, and the synthetic ammonia industry, centered on ammonia synthesis, plays a pivotal role in the national economy. As a pillar industry of the chemical industry, synthetic ammonia is characterized by large output and high energy consumption. Its working principle is to place the ammonia synthesis reaction tower under high pressure and high temperature conditions, so that nitrogen and hydrogen react in the presence of a catalyst to produce ammonia.

[0003] The ammonia synthesis reaction tower must meet the following requirements in terms of process: First, the ammonia synthesis reaction should be carried out as close as possible to the optimal temperature to obtain large production capacity and high ammonia synthesis yield; second, the pressure drop of the ammonia synthesis reaction tower should be reduced to reduce the power consumption of the circulating gas; finally, the ammonia synthesis reaction tower should be simple and reliable in structure and meet the requirements of high temperature and high pressure.

[0004] Currently, the radial flow ammonia synthesis reactors used in the market mainly consist of an outer channel, a catalyst bed, an inner channel, and a heat exchanger, etc. Figure 1 As shown, the reactant gas enters the catalyst bed through the outer channel, reacts in the catalyst bed, and then flows to the heat exchanger through the inner channel. Because the opening area of ​​the inner channel is smaller than that of the outer channel, the flow velocity of the reactant gas increases from the outside to the inside as it passes through the catalyst bed. This reduces the residence time of the reactant gas in the catalyst bed and lowers the reaction efficiency of the reaction tower. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing an internally diffused radial flow ammonia synthesis reaction tower, which can effectively extend the residence time of the reactant gas in the catalyst layer and improve the reaction efficiency.

[0006] The technical solution of this invention is: An ammonia synthesis reactor with radial flow from the inside to the outside diffusion type includes a shell. The shell is a closed cylindrical shape with a cap at the top and an air outlet at the center of the top plate; the cap is an inverted funnel shape with an air inlet that runs through the inside and outside. It also includes at least one partition; the partition is arranged radially inside the housing and divides the interior of the housing into at least two independent reaction chambers; the partition has a vent hole at its center; It also includes a catalyst layer; the catalyst layer is cylindrical and has axial through holes along its center line; the catalyst layer includes a closed shell, which is filled with catalyst; the inner and outer walls of the catalyst layer are both perforated plates; the perforation area of ​​the inner wall is smaller than that of the outer wall; the catalyst layer is disposed in the reaction chamber, its bottom is fixed to the partition plate or the bottom plate of the shell, and its outer wall and top surface are isolated from the inner wall of the reaction chamber; It also includes a heat exchange tank; the heat exchange tank is a cylindrical shape with a bottom but no top, placed in the through hole of the catalyst layer, with its upper end connected to the upper end of the catalyst layer, its lower end suspended, and adjacent to the partition or the bottom plate of the shell; the side wall of the heat exchange tank is isolated from the inner side wall of the catalyst layer. It also includes heat exchange tubes; there are multiple heat exchange tubes, all of which are straight tubes, arranged longitudinally in the heat exchange tank along the shell and passing through the bottom plate of the heat exchange tank and the partition plate. The upper end of the tubes is connected to the top plate of the shell and communicates with the end cap. The lower end of the tubes passes through the bottom plate of the heat exchange tank located at the bottommost point and is close to the bottom plate of the shell. It also includes an exhaust pipe; the exhaust pipe is a straight pipe, which is installed in the heat exchange tank, with its upper end connected to the exhaust hole and its lower end suspended and adjacent to the bottom plate of the heat exchange tank. It also includes an exhaust pipe; the exhaust pipe is a straight pipe, the lower end of which is connected to the air outlet of the top plate of the housing, and the upper end of which extends beyond the end cap.

[0007] Furthermore, the sidewall of the housing is hollow, with its upper end connected to the air inlet via a connecting pipe, and its lower end having an inlet.

[0008] Furthermore, the partition consists of two parallel pieces that divide the interior of the shell into reaction chamber I, reaction chamber II, and reaction chamber III, distributed from bottom to top.

[0009] Furthermore, the height of reaction chamber I is less than or equal to the height of reaction chamber II and the height of reaction chamber III.

[0010] Furthermore, the catalyst layer has multiple outer holes on its outer sidewall and multiple inner holes on its inner sidewall; the outer holes are arranged in a straight line with a diameter of 3-10 mm and a spacing of 30-80 mm between them; the inner holes are arranged in a straight line with a diameter of 1-5 mm and a spacing of 10-50 mm between them.

[0011] Furthermore, it also includes an inner baffle and an outer baffle; the inner baffle is a circular flat plate, laterally arranged inside the heat exchange tank and sleeved on the outlet pipe, with its outer edge isolated from the side wall of the heat exchange tank; there are multiple inner baffles, spaced apart and arranged in parallel; the outer baffle is a circular flat plate, laterally arranged inside the heat exchange tank, with its outer edge connected to the inner wall of the heat exchange tank and its inner edge isolated from the outlet pipe; there are multiple outer baffles, spaced apart and arranged in parallel; the inner and outer baffles are arranged alternately; the heat exchange pipe passes through and is connected to the inner and outer baffles.

[0012] The beneficial effects of this invention are: This invention is rationally designed and easy to use. By changing the flow direction of the reactant gas and the opening area of ​​the inner and outer walls of the catalyst layer, the reactant gas flows from the inside to the outside through each catalyst layer, and the flow rate is significantly reduced. As a result, the residence time of the reactant gas in the catalyst layer can be effectively extended, thereby improving the reaction efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a traditional ammonia synthesis tower.

[0014] Figure 2 This is a schematic diagram of the structure of the present invention.

[0015] Figure 3 This is a schematic diagram of the internal spoiler of the present invention.

[0016] Figure 4 This is a schematic diagram of the structure of the external spoiler of the present invention.

[0017] Wherein, 1-exhaust pipe; 2-end cap; 3-shell; 4-reaction chamber III; 5-third catalyst layer; 6-partition plate; 7-reaction chamber II; 8-second catalyst layer; 9-reaction chamber I; 10-first catalyst layer; 11-inlet; 12-heat exchange tank I; 13-heat exchange tank II; 14-inner baffle plate; 15-outer baffle plate; 16-heat exchange tube; 17-heat exchange tank III; 18-exhaust pipe; 19-connecting pipe; 20-mounting hole. Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] like Figures 2 to 4 As shown.

[0020] An ammonia synthesis reaction tower with radial flow diffusion from the inside out includes a shell 3, a catalyst layer, a heat exchange tank, a heat exchange tube 16, and a baffle assembly.

[0021] The housing 3 is a closed cylindrical shape with a cap 2 at the top and a vent hole at the center of its top plate. The cap 2 is an inverted funnel shape with an inlet that runs through both the inside and outside. The sidewalls of the housing 3 are hollow, with their upper ends connected to the inlet via a connecting pipe 19, and their lower ends having an inlet 11. Reactant gases can enter the sidewalls of the housing 3 through the inlet 11, and then through the connecting pipe 19 into the cap 3. The cap 2 is located at the center of the top surface of the housing 3 and is sealed to the top plate of the housing 3.

[0022] The housing 3 contains two partitions 6. These partitions 6 are flat, with a shape and size corresponding to the cross-section of the housing 3. They are radially positioned within the housing 3, dividing the interior into three independent reaction chambers: reaction chamber I9, reaction chamber II7, and reaction chamber III4, from bottom to top. The height of reaction chamber I9 is ​​less than or equal to the height of reaction chamber II7 and less than or equal to the height of reaction chamber III4, to meet the requirements of reaction production.

[0023] The partition 6 has a vent hole at its center. Meanwhile, each of the reaction chambers is equipped with a vent pipe 18. This vent pipe 18 is a straight pipe, with its upper end connected to the vent hole and its lower end suspended.

[0024] The catalyst layer is cylindrical with axial through-holes along its centerline. The catalyst layer includes a closed outer shell filled with catalyst. Multiple outer holes are provided on the outer wall of the catalyst layer. These outer holes are arranged in a row, with a diameter of 3-10 mm and a spacing of 30-80 mm between them. Multiple inner holes are provided on the inner wall of the catalyst layer. These inner holes are arranged in a row, with a diameter of 1-5 mm and a spacing of 10-50 mm between them. This allows the opening area of ​​the inner wall to be smaller than that of the outer wall, thus slowing the flow rate of the reactant gas as it flows from the inside to the outside of the catalyst layer.

[0025] The catalyst layers consist of three groups: a first catalyst layer 10, a second catalyst layer 8, and a third catalyst layer 5. Their sizes are adapted to reaction chambers I9, II7, and III4, and they are respectively disposed within each of the reaction chambers. The bottom of the first catalyst layer 10 is fixed to the bottom plate of the housing 3. The bottoms of the other catalyst layers are fixed to the partition plates. Simultaneously, the outer walls and tops of each catalyst layer are isolated from the inner walls of the reaction chambers, forming gas channels. Therefore, the first catalyst layer 10 occupies 10-20% of the total catalyst filling height, and its temperature is controlled at approximately 460-470°C. The second catalyst layer 8 occupies 20-40% of the total catalyst filling height, and its temperature is controlled at 440-450°C. The third catalyst layer 5 occupies 40-70% of the total catalyst filling height, and its temperature is controlled at 420-430°C.

[0026] The heat exchange tanks include heat exchange tank I12, heat exchange tank II13, and heat exchange tank III17, all of which are cylindrical with a bottom but no top, and are respectively placed inside the through holes of the first catalyst layer 10, the second catalyst layer 8, and the third catalyst layer 5. The upper end of the heat exchange tank is connected to the upper end of the catalyst layer, and its lower end is suspended and adjacent to the partition or the bottom plate of the shell. The sidewall of the heat exchange tank is isolated from the inner sidewall of the catalyst layer, forming a gas channel. At the same time, the gas outlet pipes in each of the reaction chambers are respectively placed in the corresponding heat exchange tanks, with their lower ends adjacent to the bottom plate of the heat exchange tank.

[0027] The heat exchange tubes 16 are multiple, all straight stainless steel tubes, arranged longitudinally along the shell 3 within the heat exchange trough, penetrating the bottom plate and the partition plate of the heat exchange trough. Their upper ends connect to the top plate of the shell and communicate with the end cap 2, while their lower ends penetrate the bottom plate of the heat exchange trough I12 and are adjacent to the bottom plate of the shell. The heat exchange tubes 16 are evenly distributed in a ring around the central axis of the shell 3. Preferably, the inner diameter of the heat exchange tubes 16 is 10~40mm. The heat exchange tubes are arranged at equal intervals. The distance between any two adjacent heat exchange tubes is 50~200mm.

[0028] The baffle assembly includes an inner baffle 14 and an outer baffle 15. The inner baffle 14 is a circular flat plate, laterally disposed within the heat exchange tank, and its inner edge is welded tightly to the outlet pipe 18. Simultaneously, the outer edge of the inner baffle 14 is isolated from the sidewall of the heat exchange tank. Multiple inner baffles 14 are arranged alternately and parallel to each other. The outer baffle 15 is a circular flat plate, laterally disposed within the heat exchange tank, and its outer edge is welded tightly to the inner wall of the heat exchange tank. Simultaneously, the outlet pipe is placed within the outer baffle 15 and isolated from its inner edge. Multiple outer baffles 15 are arranged alternately and parallel to each other. Furthermore, the inner baffles 14 and outer baffles 15 are alternately arranged, creating a labyrinthine gas flow path within the heat exchange tank.

[0029] The inner baffle 14 and the outer baffle 15 are respectively provided with mounting holes 20, so that the heat exchange tube 16 can pass through the mounting holes 20 and be tightly connected to the inner baffle 14 and the outer baffle 15.

[0030] Furthermore, it also includes an exhaust pipe 1. The exhaust pipe 1 is a straight pipe, placed inside the end cap 2, with its lower end connected to the vent hole of the top plate of the housing 3, and its upper end extending outside the end cap 2, so as to discharge the reacted gas from the housing.

[0031] The operation process of this invention is as follows: The reactant gas enters the hollow side wall of the shell through the inlet on the shell, and then flows into the end cap through the connecting pipe. During this process, the reactant gas can carry away the heat generated during the reaction inside the shell, and at the same time, it is heated itself.

[0032] The reactant gas inside the end cap flows through the heat exchange tube to the bottom of the through-hole of the first catalyst layer, where it exchanges heat with the high-temperature gas outside the heat exchange tube, raising its temperature. Then, the reactant gas flowing into the through-hole of the first catalyst layer flows from the inside to the outside through the inner and outer holes on the sidewall of the first catalyst layer, completing the first catalytic reaction.

[0033] Subsequently, the reaction gas flows into the heat exchange tank I through the gap between the first catalyst layer and the reaction chamber I, and under the action of the inner and outer baffles, it flows in an S-shape to the bottom of the heat exchange tank I, and then flows into the upper reaction chamber II through the gas outlet pipe in the heat exchange tank I.

[0034] The flow trajectories of the reactant gas in reaction chambers II and III are the same as those in reaction chamber I, thereby realizing the reaction process of the reactant gas with the second catalyst layer and the third catalyst layer, respectively.

[0035] Finally, the reacted gases, having completed the reaction, are discharged from the casing through the exhaust pipe and enter the next stage of the processing.

[0036] This invention changes the flow direction of the reactant gas and the opening area of ​​the inner and outer walls of the catalyst layer, so that the reactant gas flows from the inside to the outside through each catalyst layer and the flow rate is significantly reduced. As a result, the residence time of the reactant gas in the catalyst layer can be effectively extended, thereby improving the reaction efficiency.

[0037] All parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. An ammonia synthesis reactor with radial flow from the inside to the outside diffusion type, comprising a shell, characterized in that, The shell is a closed cylindrical shape with a cap at the top and an air outlet at the center of the top plate; the cap is an inverted funnel shape with an air inlet that runs through the inside and outside. It also includes at least one partition; the partition is arranged radially inside the housing and divides the interior of the housing into at least two independent reaction chambers; the partition has a vent hole at its center; It also includes a catalyst layer; the catalyst layer is cylindrical and has axial through holes along its center line; the catalyst layer includes a closed shell, which is filled with catalyst; the inner and outer walls of the catalyst layer are both perforated plates; the perforation area of ​​the inner wall is smaller than that of the outer wall; the catalyst layer is disposed in the reaction chamber, its bottom is fixed to the partition plate or the bottom plate of the shell, and its outer wall and top surface are isolated from the inner wall of the reaction chamber; It also includes a heat exchange tank; the heat exchange tank is a cylindrical shape with a bottom but no top, placed in the through hole of the catalyst layer, with its upper end connected to the upper end of the catalyst layer, its lower end suspended, and adjacent to the partition or the bottom plate of the shell; the side wall of the heat exchange tank is isolated from the inner side wall of the catalyst layer. It also includes heat exchange tubes; there are multiple heat exchange tubes, all of which are straight tubes, arranged longitudinally in the heat exchange tank along the shell and passing through the bottom plate of the heat exchange tank and the partition plate. The upper end of the tubes is connected to the top plate of the shell and communicates with the end cap. The lower end of the tubes passes through the bottom plate of the heat exchange tank located at the bottommost point and is close to the bottom plate of the shell. It also includes an exhaust pipe; the exhaust pipe is a straight pipe, which is installed in the heat exchange tank, with its upper end connected to the exhaust hole and its lower end suspended and adjacent to the bottom plate of the heat exchange tank. It also includes an exhaust pipe; the exhaust pipe is a straight pipe, the lower end of which is connected to the air outlet of the top plate of the housing, and the upper end of which extends beyond the end cap; The sidewall of the housing is hollow, with its upper end connected to the air inlet via a connecting pipe, and its lower end having an inlet. The catalyst layer has multiple inner holes on its inner sidewall; the catalyst layer has multiple outer holes on its outer sidewall; the inner holes are arranged in a straight line; the outer holes are arranged in a straight line. It also includes an inner baffle and an outer baffle; the inner baffle is a circular flat plate, horizontally arranged in the heat exchange tank and sleeved on the outlet pipe, with its outer edge isolated from the side wall of the heat exchange tank; there are multiple inner baffles, spaced apart and arranged in parallel; the outer baffle is a circular flat plate, horizontally arranged in the heat exchange tank, with its outer edge connected to the inner wall of the heat exchange tank and its inner edge isolated from the outlet pipe; there are multiple outer baffles, spaced apart and arranged in parallel; the inner and outer baffles are arranged alternately.

2. The radial flow ammonia synthesis reaction tower with inward diffusion as described in claim 1, characterized in that, The partition consists of two parallel pieces that divide the interior of the shell into reaction chamber I, reaction chamber II, and reaction chamber III, distributed from bottom to top.

3. The radial flow ammonia synthesis reaction tower with inward diffusion as described in claim 2, characterized in that, The height of reaction chamber I is less than or equal to the height of reaction chamber II and the height of reaction chamber III.

4. The radial flow ammonia synthesis reaction tower with inward diffusion as described in claim 1, characterized in that, The diameter of the outer hole is 3~10mm, and the spacing between the holes is 30~80mm; the diameter of the inner hole is 1~5mm, and the spacing between the holes is 10~50mm.

5. The radial flow ammonia synthesis reaction tower with inward diffusion as described in claim 1, characterized in that, The heat exchange tube is connected to the inner and outer baffles.

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