An inlet diffuser

Abstract

An inlet diffuser, belonging to the components of a hydrogenation reactor in the petrochemical field, comprises a cylinder body and a fragmentation plate arranged below the oil and gas outlet of the cylinder body. An overflow weir is arranged inside the cylinder body. The overflow weir is a truncated cone-shaped cylinder body with an arc-shaped surface. The small-diameter end of the overflow weir faces the oil and gas inlet direction, and a baffle plate is arranged. There is a side channel between the baffle plate and the overflow weir. Two overflow slits are symmetrically distributed on the surface of the overflow weir, and the connection line of these two overflow slits is perpendicular to the flow direction of the inlet pipeline on the inlet diffuser. Liquid outlet holes are unevenly distributed on the surface of the overflow weir. By setting the overflow weir with a special structure, two overflow slits and asymmetric liquid outlet holes, the inevitable flow deviation phenomenon entering the reactor can be completely improved. At the same time, the simple structure can minimize costs and reduce pressure drop as much as possible.

Description

Technical Field

[0001] The present invention relates to components of a hydrogenation reactor in the petrochemical field, specifically an inlet diffuser. Background Art

[0002] Under the background of increasingly strict environmental protection regulations, the standards for impurity content in various petroleum products are also increasing day by day. As an essential technology in the production process of clean fuels, hydrogenation technology plays a significant role in refinery production.

[0003] Hydrogenation technology includes hydrocracking, hydrofining, etc. The hydrogenation reaction is an exothermic reaction. At present, the vast majority in China adopt the structure of a down-flow fixed-bed reactor. The reaction material flows through the catalyst bed layer from top to bottom and undergoes a hydrogenation reaction under its action. The uneven distribution of gas and liquid during the reaction process will cause hot spots in the reactor, which will in turn cause coking and temperature runaway of the catalyst, affecting product quality and production safety. Therefore, a stable gas-liquid distribution is crucial for improving the flow characteristics and catalyst utilization rate in the reactor.

[0004] The inlet diffuser of the reactor is the first device that the oil and gas pass through when entering the reactor. The inlet diffuser conducts an initial distribution of the oil and gas entering the reactor and plays a crucial role in the uniformity of the gas-liquid distribution throughout the reaction process. However, the existing inlet diffusers have some deficiencies such as being unable to completely improve the problem of uneven flow, being unable to cope with large fluctuations in the gas-liquid volume, and having a relatively complex structure resulting in a large pressure drop. Summary of the Invention

[0005] In order to solve the problems of uneven flow of oil and gas and large load fluctuation range existing in the existing inlet diffuser, the present invention provides an inlet diffuser. By arranging an overflow weir with a special structure inside the barrel of the diffuser, the oil and gas are buffered and rectified, effectively improving the serious problem of uneven flow of oil and gas in the inlet diffuser and avoiding the phenomenon of uneven distribution of the internal cross-section of the reactor.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: an inlet diffuser, including a barrel and a fragmentation plate arranged below the oil and gas outlet of the barrel. An overflow weir is arranged inside the barrel. An overflow area is formed between the outer side wall of the overflow weir and the inner side wall of the barrel. The overflow weir is a truncated cone-shaped barrel with an arc-shaped surface. The small-diameter end of the overflow weir faces the oil and gas inlet direction, and a baffle is arranged, and there is a side channel between the baffle and the overflow weir; two overflow slits are symmetrically distributed on the surface of the overflow weir, and the connection line of these two overflow slits is perpendicular to the flow direction of the incoming flow of the inlet pipeline on the inlet diffuser; the connection line of the two overflow slits divides the surface of the overflow weir into a near-incoming flow area close to the flow direction of the incoming flow of the inlet pipeline and a far-incoming flow area far from the flow direction of the incoming flow of the inlet pipeline. A number of liquid outlet holes are arranged in both the near-incoming flow area and the far-incoming flow area, and the number of liquid outlet holes in the near-incoming flow area is lower than the number of liquid outlet holes in the far-incoming flow area.

[0007] As an optimized solution for the above-mentioned inlet diffuser, the baffle is fixed to the small-diameter end of the overflow weir through a number of baffle legs, and side channels are formed between the baffle legs.

[0008] As another optimized solution for the above-mentioned inlet diffuser, the edge of the baffle extends beyond the small-diameter end of the overflow weir, thereby forming a flange to prevent the backflow of oil and gas.

[0009] As another optimized solution for the above-mentioned inlet diffuser, the distance between the baffle and the small-diameter end of the overflow weir is 100 mm.

[0010] As another optimized solution for the above-mentioned inlet diffuser, the overflow slit is located in the middle of the overflow weir, and its length direction is parallel to the generatrix of the overflow weir.

[0011] As another optimized solution for the above-mentioned inlet diffuser, the length of the overflow slit is 200 - 350 mm, and the width is 10 - 30 mm.

[0012] As another optimized solution for the above-mentioned inlet diffuser, the liquid outlet holes in the near-inflow area are a row of through holes evenly distributed at the same height on the overflow weir; the liquid outlet holes in the far-inflow area are 2 - 3 rows of through holes distributed at different heights on the overflow weir.

[0013] As another optimized solution for the above-mentioned inlet diffuser, the number of liquid outlet holes in the near-inflow area is 6 - 10, and the hole diameter is 15 - 30 mm; among the 2 - 3 rows of liquid outlet holes in the far-inflow area, the number of liquid outlet holes in each row is 6 - 10, and the hole diameter is 15 - 30 mm.

[0014] As another optimized solution for the above-mentioned inlet diffuser, the fragmentation plate is fixed to the bottom of the cylinder through a number of fragmentation plate legs, and fluid channels are formed between the fragmentation plate legs.

[0015] As another optimized solution for the above-mentioned inlet diffuser, the diameter of the fragmentation plate is 5 - 10 mm smaller than the inner diameter of the cylinder, and the distance from the bottom of the cylinder is 200 mm.

[0016] As another optimized solution for the above-mentioned inlet diffuser, the fragmentation plate is a circular flat plate, and two circles of through holes are arranged around the center on its surface.

[0017] As another optimized solution for the above-mentioned inlet diffuser, the two circles of through holes are located on the outer side of the surface of the fragmentation plate, and the numbers are 12 and 18 respectively, and the hole diameter is 30 mm.

[0018] As another optimization solution for the above inlet diffuser, a positioning groove is provided on the side wall of the cylinder body, and when the overflow weir is installed in the cylinder body, the connection line of the two overflow slits is perpendicular to the flow direction of the inlet pipeline on the inlet diffuser.

[0019] As another optimization solution for the above inlet diffuser, the height of the cylinder body is 1000 mm, the wall thickness is 5 - 8 mm, and the outer diameter is 10 - 30 mm smaller than the inlet diameter of the reactor it cooperates with.

[0020] The working principle of the present invention is as follows: Oil and gas come down from the upper part of the reactor and enter the cylinder body of the inlet diffuser of the present invention. First, it contacts the baffle plate. After being buffered and deflected by the baffle plate, the oil and gas enter the overflow weir. Since the overflow weir is a circular cylinder with a smaller upper part and a larger lower part, and its surface is arc-shaped, similar to a flared shape, this special-structured overflow weir can buffer and rectify the liquid. Then, a part of the oil and gas flows down through the liquid outlet holes on the surface of the overflow weir, and more oil and gas overflows downward through the side channels between the overflow weir and the baffle plate. After flowing down from the overflow weir, the oil and gas impact the fragmentation plate located at the bottom of the inlet diffuser from the center of the diffuser cylinder body. After passing through the fragmentation plate, the oil and gas are evenly dispersed into the reactor interior.

[0021] When the present invention works, oil and gas enter from the reactor inlet and first contact the baffle plate. After being deflected by the baffle plate, the oil and gas enter the overflow area, and the liquid phase accumulates in the overflow area. Since it is inevitable that the oil in the pipeline will generate a flow deviation phenomenon when entering the reactor interior, that is, more oil will flow to one side away from the flow direction of the inlet pipeline. In order to avoid the uneven overflow of the fluid entering the overflow weir caused by the flow deviation of the inlet pipeline. Asymmetric liquid outlet holes are opened on the surface of the overflow weir. Two or three layers of liquid outlet holes are opened on the side with more flow deviation, and one layer of liquid outlet holes is opened on the other side. Ensure the circumferential uniformity of the fluid during overflow. An overflow slit is also provided perpendicular to the flow direction of the oil and gas to dynamically adjust the fluid in the overflow weir. When the oil and gas flow into the overflow weir, a flow to both sides will be formed. These two overflow slits enable the liquid phase accumulated on both sides to flow down smoothly, avoiding the phenomenon of uneven overflow. The fluid flowing out by overflow impacts the baffle plate for deflection and then flows down from the center of the cylinder body. The oil and gas flowing down from the center of the cylinder body impact the fragmentation plate located below the cylinder body. The center of the fragmentation plate is a closed plate, and through holes are opened around it. The axial flow is converted into a plug flow through the fragmentation plate, so that the fluid diffuses in the head space.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) By setting an overflow weir with a special structure, the present invention enables the oil and gas to be buffered and rectified on the overflow weir first, effectively improving the serious problem of uneven flow of oil and gas at the inlet and avoiding the phenomenon of uneven distribution of the internal cross-section of the reactor; the overflow weir is set as a truncated cone-shaped cylinder with an arc-shaped surface, which can make the fluid overflow evenly in the circumferential direction and is more uniform for the circular cross-section distribution of the reactor; at the same time, liquid outlet holes that are uneven in the circumferential direction are arranged on the overflow weir, which can further prevent the uneven flow of oil and gas from the pipeline; when the oil and gas flow into the overflow weir, a tendency to flow towards both sides will be formed, and two overflow slits are arranged perpendicular to the flow direction of the oil and gas, which can dynamically adjust the fluid in the overflow weir, enabling the liquid phase accumulated on both sides to flow down smoothly and avoiding the phenomenon of uneven overflow.

[0024] 2) By setting baffle plates, the present invention can ensure that the oil and gas entering the reactor will not directly impact and enter the interior of the reactor, causing instability in the cross-section distribution of the reactor. At the same time, the baffle plates extend beyond the top of the overflow weir to form a flange, which not only prevents the oil and gas from flowing back but also can guide the oil and gas into the flared overflow weir, further blocking and deflecting the overflowing oil and gas in the overflow weir to ensure the uniform and stable flow of the oil and gas after overflow.

[0025] 3) By setting a fragmentation plate, the present invention can cause the oil and gas flowing down from the center of the inlet diffuser to have a perpendicular impact for deflection and diffusion, changing the axial flow of gas and liquid to radial flow, and radially impacting the gas-liquid flow flowing out of other gas-liquid distributors in a plug flow manner and then being evenly distributed in the catalyst bed.

[0026] 4) By setting an overflow weir with a special structure, two overflow slits, and asymmetric liquid outlet holes, the present invention can completely improve the inevitable uneven flow phenomenon when entering the interior of the reactor. At the same time, the simple structure can minimize costs and reduce pressure drop as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 is a schematic diagram of the structure of the overflow weir;

[0029] Figure 3 is Figure 1 a cross-sectional view taken along the A-A direction in

[0030] Figure 4 is Figure 1 a cross-sectional view taken along the B-B direction in

[0031] Reference numerals: 1, cylinder body; 2, overflow weir; 201, overflow area; 202, overflow slit; 203, near flow area; 204, far flow area; 3, flow-breaking plate; 301, flow-breaking plate support leg; 302, through hole; 4, baffle plate; 401, flange; 402, baffle plate support leg; 5, side channel; 6, positioning groove. Detailed implementation mode

[0032] The technical solution of the present invention will be further elaborated in detail below in combination with specific embodiments. For parts not clarified in the following embodiments of the present invention, they should all be understood as technologies known or should be known to those skilled in the art, such as the installation of the inlet diffuser and the reactor, the connection between the inlet diffuser and the inlet pipeline, etc.

[0033] Embodiment 1

[0034] An inlet diffuser, as Figure 1 shown, includes a cylinder body 1 and a flow-breaking plate 3 arranged below the oil and gas outlet of the cylinder body 1. The top opening of the cylinder body 1 is the oil and gas inlet, and the bottom opening is the oil and gas outlet. The flow-breaking plate 3 is outside the cylinder body 1. An overflow weir 2 is arranged in the cylinder body 1. An overflow area 201 is formed between the outer side wall of the overflow weir 2 and the inner side wall of the cylinder body 1. The overflow weir 2 is a frustum-shaped cylinder with an arc-shaped surface. As Figure 2 shown, the frustum-shaped cylinder means that each horizontal cross-section of the overflow weir 2 is circular, but the diameter gradually increases from top to bottom, and the increase is uneven, thus forming a cylinder with an arc-shaped generatrix, similar to a horn shape. The top is the small-diameter end, and the bottom is the large-diameter end. The large-diameter end is matched with the inner wall of the cylinder body 1 to realize the fixation of the overflow weir 2 in the cylinder body 1; the small-diameter end of the overflow weir 2 faces the oil and gas inlet direction, and a baffle plate 4 is arranged at a certain distance above it. A side channel 5 is formed between the baffle plate 4 and the overflow weir 2; two overflow slits 202 are symmetrically distributed on the surface of the overflow weir 2, and the connection line of these two overflow slits 202 is perpendicular to the flow direction of the inlet pipeline on the inlet diffuser. The inlet pipeline refers to the inlet pipeline that is introduced into the inlet diffuser when the inlet diffuser is applied to a hydrogenation reactor. Generally, the inlet pipeline is L-shaped. After coming from the horizontal direction perpendicular to the axis of the cylinder body 1, it then turns vertically and is introduced into the top of the inlet diffuser. The flow direction of the inlet pipeline refers to the orientation of the horizontal section of the inlet pipeline; the connection line of the two overflow slits 202 divides the surface of the overflow weir 2 into a near flow area 203 close to the flow direction of the inlet pipeline and a far flow area 204 far from the flow direction of the inlet pipeline. As Figure 3As shown, the recent flow area 203 and the far - away flow area 204 are symmetric along the connection line of the overflow seam 202. Both are 180° arc surfaces with the center of the small - diameter end of the overflow weir 2 as the center of the circle. A number of liquid - outlet holes are provided on both the recent flow area 203 and the far - away flow area 204, and the number of liquid - outlet holes on the recent flow area 203 is lower than that on the far - away flow area 204. The liquid - outlet holes on the recent flow area 203 and the far - away flow area 204 are all located at the position near the top of their respective areas, that is, the part close to the side channel 5.

[0035] The above is the basic implementation mode of the present invention. Further improvements, optimizations and limitations can be made on this basis to obtain the following embodiments:

[0036] Embodiment 2

[0037] This embodiment is an improved scheme based on Embodiment 1. Its main structure is the same as that of Embodiment 1. The improvement lies in: as Figure 2 shown, the baffle 4 is fixed at the small - diameter end of the overflow weir 2 through a number of baffle legs 402. The number of baffle legs 402 is 2 - 6. This setting will not block the fluid on the one hand, and on the other hand, it can withstand the impact of the fluid under the condition of using fewer supports, avoiding uneven fluid. Side channels 5 are formed between the baffle legs 402; the distance between the baffle 4 and the small - diameter end of the overflow weir 2 is 100 mm; the baffle 4 is a circular thin plate and is coaxial with the small - diameter end of the overflow weir 2, and its diameter is slightly larger than the diameter of the small - diameter end of the overflow weir 2, generally 50 - 100 mm larger, so that its edge extends beyond the small - diameter end of the overflow weir 2 to form a flange 401 for preventing oil - gas backflow. <(

[0038] Embodiment 3

[0039] This embodiment is another improved scheme based on Embodiment 1. Its main structure is the same as that of Embodiment 1. The improvement lies in: as Figure 2 and Figure 3 shown, the overflow seam 202 is located at the middle position in the height direction of the overflow weir 2, and its length direction is parallel to the generatrix of the overflow weir 2. The length of the overflow seam 202 is 200 - 350 mm, and the width is 10 - 30 mm.

[0040] Embodiment 4

[0041] This embodiment is another improved scheme based on Embodiment 1. Its main structure is the same as that of Embodiment 1. The improvement lies in: as Figure 2 and Figure 3 shown, the liquid - outlet holes on the recent flow area 203 are a row of through - holes evenly distributed at the same height on the overflow weir 2; the liquid - outlet holes on the far - away flow area 204 are 2 - 3 rows of through - holes distributed at different heights on the overflow weir 2;

[0042] The number of liquid outlet holes on the recent flow area 203 is 6 - 10, and the hole diameter is 15 - 30 mm, such as 15 mm, 20 mm, 25 mm, 30 mm, etc.; among the 2 - 3 discharge liquid holes on the far - away flow area 204, the number of each discharge liquid hole is 6 - 10, and the hole diameter is 15 - 30 mm, such as 15 mm, 20 mm, 25 mm, 30 mm, etc.

[0043] Figure 2 and Figure 3 As shown in [reference], the liquid outlet holes on the far - away flow area 204 are arranged in 2 rows, and the height of the first row is the same as the height of the liquid outlet holes on the recent flow area 203, and they are on the same circle around the center of the overflow weir 2. Figure 2 and Figure 3 In [reference], liquid outlet holes are arranged corresponding to the position of the overflow slit 202. Since the liquid outlet holes are on the demarcation line between the recent flow area 203 and the far - away flow area 204, the liquid outlet holes on the demarcation line belong to both the recent flow area 203 and the far - away flow area 204.

[0044] Example 5

[0045] This example is another improvement scheme based on Example 1. Its main structure is the same as that of Example 1. The improvement lies in: as Figure 1 shown, the fragmentation plate 3 is fixed at the bottom of the cylinder 1 through several fragmentation plate legs 301. The number of fragmentation plate legs 301 is 4, which are evenly arranged. Without blocking the fluid as much as possible while ensuring strength, fluid channels are formed between the fragmentation plate legs 301.

[0046] The fragmentation plate 3 is connected below the cylinder 1. Since the oil - gas flows down from the center of the cylinder 1, the diameter of the fragmentation plate 3 is slightly smaller than the inner diameter of the cylinder 1, generally 5 - 10 mm smaller than the inner diameter of the cylinder 1. On the one hand, it can ensure that the inlet diffuser smoothly enters the reactor interior, and on the other hand, it can save materials and space. The distance between the fragmentation plate 3 and the bottom of the cylinder 1 is 200 mm.

[0047] as Figure 4 shown, the fragmentation plate 3 is a circular flat plate, and two circles of through - holes 302 are arranged around the center on its surface. The two circles of through - holes 302 are on the outer side of the surface of the fragmentation plate 3, and the number of them is 12 and 18 respectively, and the hole diameter is 30 mm.

[0048] Example 6 [[ID=z32]]

[0049] This example is another improvement scheme based on Example 1. Its main structure is the same as that of Example 1. The improvement lies in: as Figure 1As shown, a positioning groove 6 is provided on the side wall of the cylinder body 1. The positioning groove 6 is used for positioning when it is installed on the reactor. When the overflow weir 2 is installed in the cylinder body 1, the connection line of the two overflow slits 202 is perpendicular to the flow direction of the inlet pipeline on the inlet diffuser.

[0050] The cylinder body 1 is cylindrical, and its wall thickness can be 5 - 8 mm, such as 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, etc. The cylinder body 1 is determined according to the actual inlet diameter of the reactor. The outer diameter is 10 - 30 mm smaller than the inlet diameter of the reactor it cooperates with, and the height is generally 1000 mm, and the wall thickness is 5 - 8 mm, such as 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, etc.

[0051] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An inlet diffuser, comprising a cylinder body (1) and a flow-breaking plate (3) arranged below the oil and gas outlet of the cylinder body (1). The center of the flow-breaking plate (3) is a closed plate, and through holes are opened around it. The axial flow is converted into a plug flow through the flow-breaking plate (3). An overflow weir (2) is arranged in the cylinder body (1). An overflow region (201) is formed between the outer side wall of the overflow weir (2) and the inner side wall of the cylinder body (1). It is characterized in that: The overflow weir (2) is a truncated cone-shaped cylinder with an arc-shaped surface. The small-diameter end of the overflow weir (2) faces the oil and gas inlet direction, and a baffle plate (4) is provided. There is a side channel (5) between the baffle plate (4) and the overflow weir (2). Two overflow slits (202) are symmetrically distributed on the surface of the overflow weir (2), and the connection line of these two overflow slits (202) is perpendicular to the flow direction of the inlet pipeline on the inlet diffuser. The connection line of the two overflow slits (202) divides the surface of the overflow weir (2) into a near-flow region (203) close to the flow direction of the inlet pipeline and a far-flow region (204) far from the flow direction of the inlet pipeline. A number of liquid outlet holes are provided in both the near-flow region (203) and the far-flow region (204), and the number of liquid outlet holes in the near-flow region (203) is lower than that in the far-flow region (204).

2. The inlet diffuser according to claim 1, wherein: The baffle plate (4) is fixed to the small-diameter end of the overflow weir (2) through a number of baffle legs (402), and a side channel (5) is formed between the baffle legs (402).

3. An inlet diffuser according to claim 1, characterized in that: The edge of the baffle plate (4) extends beyond the small-diameter end of the overflow weir (2), thereby forming a flange (401) to prevent the oil and gas from flowing back.

4. An inlet diffuser according to claim 1, characterized in that: The distance between the baffle plate (4) and the small-diameter end of the overflow weir (2) is 100 mm.

5. An inlet diffuser according to claim 1, characterized in that: The overflow slit (202) is located in the middle of the overflow weir (2), and its length direction is parallel to the generatrix of the overflow weir (2).

6. An inlet diffuser according to claim 1 or 5, characterized in that: The length of the overflow slit (202) is 200 - 350 mm, and the width is 10 - 30 mm.

7. An inlet diffuser according to claim 1, characterized in that: The liquid outlet holes in the near-flow region (203) are a row of through holes evenly distributed at the same height on the overflow weir (2); the liquid outlet holes in the far-flow region (204) are 2 - 3 rows of through holes distributed at different heights on the overflow weir (2).

8. An inlet diffuser according to claim 7, characterized in that: The number of liquid outlet holes in the near-flow region (203) is 6 - 10, and the hole diameter is 15 - 30 mm; among the 2 - 3 rows of liquid outlet holes in the far-flow region (204), the number of liquid outlet holes in each row is 6 - 10, and the hole diameter is 15 - 30 mm.

9. The inlet diffuser according to claim 1, characterized in that: The fragmentation plate (3) is fixed to the bottom of the cylinder (1) through a number of fragmentation plate legs (301), and a fluid channel is formed between the fragmentation plate legs (301).

10. An inlet diffuser according to claim 1, characterized in that: The diameter of the fragmentation plate (3) is 5 - 10 mm smaller than the inner diameter of the cylinder (1), and the distance from the bottom of the cylinder (1) is 200 mm.

11. The inlet diffuser according to claim 1, wherein: The fragmentation plate (3) is a circular flat plate, and two circles of through holes (302) are arranged around the center on its surface.

12. An inlet diffuser according to claim 11, characterized in that: The two circles of through holes (302) are located on the outer side of the surface of the fragmentation plate (3), and the numbers are 12 and 18 respectively, and the hole diameter is 30 mm.

13. An inlet diffuser according to claim 1, characterized in that: A positioning groove (6) is provided on the side wall of the cylinder (1), and when the overflow weir (2) is installed in the cylinder (1), the connection line of the two overflow slits (202) is perpendicular to the flow direction of the inlet pipeline on the inlet diffuser.

14. An inlet diffuser according to claim 1, characterized in that: The height of the cylinder (1) is 1000 mm, the wall thickness is 5 - 8 mm, and the outer diameter is 10 - 30 mm smaller than the inlet diameter of the reactor it cooperates with.

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