Liquid caustic soda concentration device in caustic soda flake production

Abstract

The utility model provides a caustic soda liquid concentration device in caustic soda flake production. The caustic soda liquid concentration device comprises a tank body; the three layers of baffle plates are arranged in the tank body at equal intervals; fan-shaped notches are formed in the baffle plates, so that a shell pass medium flows from the baffle plate on the upper layer to the baffle plate on the lower layer; the heat exchange tubes penetrate through the baffle plates; the pull rod is connected with the baffle plate; the pull rod comprises an upper pull rod and a lower pull rod; the upper pull rod penetrates through the end surface of the top baffle plate; the lower pull rod penetrates through the end face of the bottommost baffle plate; the ball joint part is connected with the upper pull rod and the lower pull rod; the ball joint part comprises a ball head for connecting the end parts of the upper pull rod and the lower pull rod; and the sleeve covers the ball head. The ball joint part is arranged between the upper pull rod and the lower pull rod, so that an included angle can be formed between the upper pull rod and the lower pull rod to absorb thermal expansion difference of the pull rods caused by temperature difference, and the problem that in the prior art, a baffle plate inclines due to deformation of the pull rods, and then a heat exchange pipe is locally thinned or broken due to friction and extrusion is solved.

Description

Technical Field

[0001] This utility model relates to the technical field of alkali concentration, and in particular to a liquid alkali concentration device in the production of caustic soda flakes. Background Technology

[0002] The liquid caustic soda concentration unit is a core piece of equipment in the caustic soda flake production process. Its function is to increase the concentration of low-concentration liquid caustic soda (such as 32% or 50%) to a high concentration (above 98.5%) through an evaporation and concentration process, providing qualified raw materials for subsequent flake production. This unit typically employs multi-effect falling film evaporation technology, using steam or molten salt as a heat source. The liquid caustic soda forms a thin film flow within the heat exchange tubes and evaporates under heat. After the concentrated caustic soda solution is separated from the secondary steam, it is further concentrated to the target concentration in a flash tank.

[0003] In heat exchange concentrators, baffles are often added to the outer wall of the heat exchange tubes to guide the flow of the shell-side medium, thereby increasing the flow velocity of the shell-side medium and improving the heat exchange efficiency.

[0004] The prior art discloses a utility model patent entitled: Novel Caustic Soda Single-Effect Heat Exchanger Concentrator, publication number: CN207169069U. It includes a tank with a top opening and a cover movably disposed on the top of the tank. An upper tube sheet and a lower tube sheet are fixedly arranged vertically inside the tank. Several pairs of tube holes are correspondingly provided on the upper and lower tube sheets. A heat exchange tube is fixed between each pair of tube holes. Several baffles are staggered on the inner wall of the tank between the upper and lower tube sheets. The heat exchange tube passes through the baffles and is fixedly connected to the baffles. A tie rod is vertically fixed between every two baffles.

[0005] However, according to the patent application, due to the significant temperature difference between the inside and outside of the heat exchange tube, and the difference between the high-temperature alkaline solution inside the tube and the cooling medium in the shell side, the thermal expansion coefficients of the tie rod and the heat exchange tube materials differ. When the temperature fluctuates drastically, the tie rod generates internal stress due to uneven heating, which accumulates over time and leads to plastic deformation. This deformation causes changes in the baffle spacing or tilting, subjecting the heat exchange tube to shear forces in non-perpendicular directions. When the baffles come into contact with the tube wall, friction and compression can cause localized thinning or cracking of the tube wall. Utility Model Content

[0006] The purpose of this invention is to solve the problem in the prior art where the deformation of the tie rod causes the baffle plate to tilt, which in turn leads to friction and compression of the heat exchange tube, resulting in local thinning or rupture of the tube wall.

[0007] To achieve the above objectives, this application proposes a liquid caustic soda concentration device for caustic soda flake production, comprising:

[0008] Tank body;

[0009] Three layers of baffles are arranged at equal intervals in the tank body; the baffles are provided with fan-shaped notches to allow the shell-side medium to flow from the upper baffle to the lower baffle;

[0010] Heat exchange tubes penetrating the baffle plate;

[0011] A connecting rod for the baffle plate; the connecting rod includes: an upper connecting rod penetrating the end face of the topmost baffle plate; a lower connecting rod penetrating the end face of the bottommost baffle plate; a ball joint connecting the upper connecting rod and the lower connecting rod; the ball joint includes: a ball head connecting the ends of the upper connecting rod and the lower connecting rod; and a sleeve covering the ball head.

[0012] The liquid alkali concentration device of this application is equipped with a two-section tie rod. The ball joint between the upper and lower tie rods allows the upper and lower tie rods to form an angle to absorb the thermal expansion difference caused by the temperature difference. This solves the problem in the prior art where tie rod deformation causes the baffle plate to tilt, which in turn causes friction and compression of the heat exchange tube, resulting in local thinning or cracking of the tube wall.

[0013] Furthermore, the fan-shaped notches of adjacent baffles are arranged in an alternating pattern.

[0014] Furthermore, the pull rod passes through the fan-shaped notch and is only in contact with the two layers of the baffles.

[0015] Furthermore, in order to reduce spherical wear, an annular corrugated groove is provided between the ball head and the sleeve.

[0016] Furthermore, in order to achieve active absorption of axial thermal displacement through the combination design of the corrugated compensator and the limiting tie rod, the ends of the upper tie rod and the lower tie rod are connected in series with corrugated compensators in the axial direction. The corrugated compensator includes: a support base connected to the ends of the upper tie rod and the lower tie rod through a flange; a limiting tie rod arranged on the support base and extending in a direction away from the tie rod; and a guide seat that is penetrated by the limiting tie rod and arranged in the axial direction of the tie rod.

[0017] Furthermore, in order to enhance stability during axial compensation through a symmetrical double-limiting tie rod layout, the number of limiting tie rods is at least two, and they are symmetrically arranged on the end face of the support base.

[0018] Furthermore, in order to form a multi-point support through the rigid connection between the guide seat and the tank, the guide seat is connected to the inner wall of the tank through the base.

[0019] The beneficial effects of this application are as follows:

[0020] 1. The liquid alkali concentration device of this application is equipped with a two-section tie rod. The ball joint between the upper tie rod and the lower tie rod can form an angle to absorb the thermal expansion difference caused by the temperature difference of the tie rod. This solves the problem in the prior art where the deformation of the tie rod causes the baffle plate to tilt, which in turn causes friction and compression of the heat exchange tube, resulting in local thinning or cracking of the tube wall.

[0021] 2. This application uses corrugated compensators at the ends of the upper and lower tie rods to absorb the axial expansion and contraction of the tie rods, thereby further preventing the heat exchange tubes from breaking due to thermal expansion of the tie rods. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a liquid caustic soda concentration device in the production of caustic soda flakes according to an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the internal structure of a liquid caustic soda concentration device in the production of caustic soda flakes, as described in an embodiment of this application.

[0025] Figure 3 This is a cross-sectional view of a liquid caustic soda concentration device in the production of caustic soda flakes, as described in an embodiment of this application.

[0026] Figure 4 for Figure 3 Enlarged view of point a in the middle.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Tank body;

[0029] 2. Baffle plate; 21. Fan-shaped notch;

[0030] 3. Heat exchanger tubes;

[0031] 4. Pull rod; 41. Upper pull rod; 42. Lower pull rod; 43. Ball joint; 431. Ball head; 432. Sleeve; 433. Annular corrugated groove; 44. Corrugated compensator; 441. Support seat; 442. Limiting pull rod; 443. Guide seat; 444. Base. Detailed Implementation

[0032] The following will be combined with the appendix Figures 1-4The embodiments of the technical solutions of this application are described in detail below. The following embodiments are only used to more clearly illustrate the technical solutions of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application. Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0033] like Figures 1-2 This illustration shows a liquid alkali concentration device in the production of caustic soda flakes, with the overall structure arranged as follows: Figure 1 As shown, the tank 1 of this device is a vertical cylindrical pressure vessel with three layers of baffles 2 arranged at equal intervals along the axial direction inside. Each layer of baffles 2 is fixed to the inner wall of the tank 1 by welding. Heat exchange tubes 3 penetrate all the baffles 2 vertically, and their upper and lower ends are welded to the tube sheet at the top and the liquid collection plate at the bottom of the tank 1, respectively, forming a liquid alkali flow channel.

[0034] Each baffle plate 2 has a 120° sector-shaped notch 21, and the sector-shaped notches 21 of adjacent baffle plates 2 are staggered to increase the flow path of shell-side media such as steam or molten salt.

[0035] Furthermore, the tie rod connection structure and thermal compensation mechanism can absorb the elastic deformation of the tie rod. The tie rod 4 includes an upper tie rod 41, a lower tie rod 42, and a ball joint 43. The upper tie rod 41 penetrates the end face of the top baffle plate 2 and is fixed to the support flange at the top of the tank 1 via a threaded connection. The lower tie rod 42 penetrates the end face of the bottom baffle plate 2, and its end is welded to the positioning plate at the bottom of the tank 1. The ball joint 43 is located below the intermediate baffle plate 2, and its ball head 431 is connected to the lower end of the upper tie rod 41 via a tapered surface fit. A 0.5-1.0mm gap is maintained between the inner wall of the sleeve 432 and the ball head 431, and this gap is filled with high-temperature resistant grease. An annular corrugated groove 433 is provided on the contact surface between the ball head 431 and the sleeve 432, with a groove width of 2mm and a depth of 1mm, effectively reducing frictional resistance.

[0036] When the device is running, if the upper pull rod 41 and the lower pull rod 42 have an axial displacement difference due to temperature difference, the ball joint 43 can allow the two to form an angle of ±5°, thereby releasing thermal stress and preventing the pull rod from bending and deforming.

[0037] Furthermore, in order to achieve axial compensation of the bellows compensator, a set of bellows compensators 44 are connected in series at the top of the upper tie rod 41 and the bottom of the lower tie rod 42: the support base 441 is connected to the end of the tie rod through a flange, and four sets of evenly distributed limiting tie rods 442 are set on its outer edge. The diameter of the limiting tie rod 442 is 1 / 3 of the diameter of the tie rod 4, and the surface is plated with hard chrome; the guide seat 443 is sleeved on the outside of the limiting tie rod 442 and welded to the inner wall of the tank 1 through the base 444. The inner hole of the guide seat 443 is clearance-fitted with the limiting tie rod 442, allowing axial displacement of ±20mm.

[0038] When the tie rod 4 expands due to heat, the bellows of the bellows compensator 44 undergoes axial deformation, and the limiting tie rod 442 slides within the guide seat 443 to ensure a smooth compensation process without deflection.

[0039] Workflow

[0040] Low-concentration liquid alkali enters the heat exchange tube 3 from the top of tank 1, forming a falling film flow inside the tube; the shell-side medium spirals upward through the fan-shaped notch 21, fully exchanging heat with the outer wall of the heat exchange tube 3. When temperature fluctuations cause the tie rod 4 to expand thermally, the ball joint 43 absorbs angular displacement, and the corrugated compensator 44 absorbs axial displacement, ensuring that the baffle 2 always remains horizontal, and the heat exchange tube 3 only bears vertical loads, effectively avoiding damage to the tube wall.

[0041] In the description of the embodiments of this application, the technical terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0042] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "set," "equipped with," "connected," and "installed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid caustic soda concentration device for caustic soda flake production, characterized in that, include: Tank body (1); Three layers of baffles (2) are arranged at equal intervals in the tank (1); the baffles (2) are provided with fan-shaped notches (21) to allow the shell medium to flow from the upper baffle (2) to the lower baffle (2); Heat exchange tube (3) passing through the baffle (2); A pull rod (4) connecting the baffle (2); the pull rod (4) includes: an upper pull rod (41) penetrating the end face of the topmost baffle (2); a lower pull rod (42) penetrating the end face of the bottommost baffle (2); a ball joint (43) connecting the upper pull rod (41) and the lower pull rod (42); the ball joint (43) includes: a ball head (431) connecting the ends of the upper pull rod (41) and the lower pull rod (42); and a sleeve (432) covering the ball head (431).

2. The liquid caustic soda concentration device in the production of caustic soda flakes according to claim 1, characterized in that, The fan-shaped notches (21) of the adjacent baffles (2) are arranged in an alternating pattern.

3. The liquid caustic soda concentration device in the production of caustic soda flakes according to claim 1, characterized in that, The pull rod (4) passes through the fan-shaped notch (21) and is only connected to the two layers of the baffles (2).

4. The liquid caustic soda concentration device in the production of caustic soda flakes according to claim 1, characterized in that, An annular corrugated groove (433) is provided between the ball head (431) and the sleeve (432).

5. The liquid caustic soda concentration device in the production of caustic soda flakes according to claim 1, characterized in that, The upper pull rod (41) and the lower pull rod (42) are connected in series with a corrugated compensator (44) at their ends. The corrugated compensator (44) includes: a support base (441) connected to the ends of the upper pull rod (41) and the lower pull rod (42) via a flange; a limiting pull rod (442) arranged on the support base (441) and extending in a direction away from the pull rod (4); and a guide seat (443) penetrated by the limiting pull rod (442) and arranged axially along the pull rod (4).

6. The liquid caustic soda concentration device in the production of caustic soda flakes according to claim 5, characterized in that, The number of the limiting rods (442) is at least two, and they are symmetrically arranged on the end face of the support (441).

7. The liquid caustic soda concentration device in the production of caustic soda flakes according to claim 5, characterized in that, The guide seat (443) is connected to the inner wall of the tank (1) via the base (444).

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