A causticization reactor

Abstract

The utility model belongs to the technical field of reaction kettle, disclose a causticization reaction kettle, including kettle body, the top of kettle body is installed with feed pipe and exhaust pipe, the bottom of kettle body is installed with discharge pipe, still include: stirring mechanism, stirring mechanism includes drive link, the outer surface of drive link is installed with multistage combination stirrer, multistage combination stirrer includes wall scraping wheel, radial stirring paddle and axial dispersion wheel, drive link is by driving piece drive, the residue structure, the residue structure includes spiral residue paddle, and the rotation of spiral residue paddle is synchronous with drive link setting. The utility model through by wall scraping wheel, radial stirring paddle and axial dispersion wheel constitute's multistage combination stirrer's synergies, thoroughly eliminates the stirring dead zone, realizes solid liquid quick homogenization, and the combination of axial dispersion wheel is inclined downwardly to the flow guide hole, strengthens bottom material circulation, especially for the lime milk and clear liquid of big density difference, to shorten the reaction period and improve causticization conversion rate.

Description

Technical Field

[0001] This utility model relates to the field of reaction vessel technology, and in particular to a causticizing reaction vessel. Background Technology

[0002] Causticization reaction is a key process in chemical industries such as alkali production and papermaking. It mainly refers to the process of lime milk reacting with sodium carbonate solution to produce sodium hydroxide and calcium carbonate precipitates. This reaction is a solid-liquid heterogeneous reaction, and its reaction efficiency and final conversion rate are highly dependent on the control of reaction conditions.

[0003] Most existing causticizing reactors adopt a simple tank structure with a stirring paddle. This traditional structure has the following problems: 1) Low reaction efficiency: A single stirring paddle is difficult to achieve full and rapid mixing of reactants, especially lime slurry (solid-liquid mixture) with large density differences and clear liquid. It is easy to form a stirring dead zone, resulting in a long reaction cycle and unsatisfactory conversion rate.

[0004] 2) Difficulty in precipitation and slag removal: The calcium carbonate particles generated by the reaction are small and have a slow settling speed. The static separation takes too long. At the same time, the precipitate accumulates densely at the bottom of the vessel, which can easily block the pipes during discharge and is difficult to completely remove, affecting the purity of the next batch of reactants and the cleanliness of the vessel. Therefore, we have proposed a causticizing reactor. Utility Model Content

[0005] In view of the problems of low reaction efficiency and difficulty in precipitation and slag removal in the existing causticizing reactors, this utility model is proposed.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution: A causticizing reactor includes a reactor body, with a feed pipe and an exhaust pipe connected to each other installed at the top of the reactor body, and a discharge pipe connected to each other installed at the bottom of the reactor body. The reactor also includes: The stirring mechanism includes a drive rod that is perpendicular to and rotatably mounted on the vessel body. A multi-stage combined stirrer is mounted on the outer surface of the drive rod. The multi-stage combined stirrer includes a wall scraping wheel, a radial stirring paddle, and an axial dispersing wheel arranged sequentially from top to bottom on the drive rod. The drive rod is driven by a drive component. The slag discharge structure includes a spiral slag discharge paddle installed on one end of the drive rod, and the rotation of the spiral slag discharge paddle is synchronized with the drive rod.

[0007] As a technical solution of the causticizing reactor described in this utility model, the bottom of the reactor body is an inverted conical structure, and the cone angle of the inverted conical structure matches the guide angle of the spiral slag discharge impeller.

[0008] As a technical solution of the causticizing reactor of this utility model, the wall scraper is mounted on the drive rod by a cross, and scrapers arranged in a circular array are installed at the bottom of the wall scraper, and the scrapers are in close contact with the inner wall of the reactor body.

[0009] As a technical solution of the causticizing reactor described in this utility model, the scraper is made of a flexible material.

[0010] As a technical solution of the causticizing reactor of this utility model, the axial dispersion wheel has dispersion plates arranged in a circumferential array and staggered vertically, and the axial dispersion wheel has guide holes arranged in a circumferential array and inclined.

[0011] As a technical solution of the causticizing reactor of this utility model, the inclination angle of the guide hole is 5°-10°, and the inclination direction of the guide hole is inclined downward.

[0012] As a technical solution of the causticizing reactor of this utility model, the driving component is a variable frequency motor, which is installed on the top of the reactor body, and the output shaft of the variable frequency motor is connected to one end of the driving rod.

[0013] As a technical solution of the causticizing reactor described in this utility model, wherein: an electric valve for controlling the slag discharge flow rate is installed on the discharge pipe.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This utility model, through the synergistic effect of a multi-stage combined agitator consisting of a wall scraper, a radial stirring paddle, and an axial dispersing wheel, completely eliminates the stirring dead zone and achieves rapid homogenization of solid and liquid. At the same time, combined with the downward-sloping guide holes on the axial dispersing wheel, it enhances the circulation of materials at the bottom, especially for lime slurry and clear liquid with large density differences, so as to shorten the reaction cycle and improve the causticization conversion rate.

[0015] 2. This utility model achieves continuous and smooth discharge of precipitates by geometrically matching the spiral slag discharge paddle with the conical bottom of the vessel and cooperating with the electric valve to control the flow rate. At the same time, it combines a flexible scraper and a dynamic slag discharge mechanism to prevent the caking of fine calcium carbonate particles, reduce residue at the bottom of the vessel, and ensure the purity of reactants and the cleanliness of the equipment between batches. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of 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. Among them: Figure 1 This is a schematic diagram of the main structure of this utility model.

[0017] Figure 2 This is a cross-sectional structural diagram of the present invention.

[0018] Figure 3 This is a schematic diagram of the stirring mechanism of this utility model.

[0019] Figure 4 For the present utility model Figure 3 Enlarged structural diagram at point A in the middle.

[0020] Explanation of reference numerals in the attached figures: In the diagram: 1. Kettle body; 101. Feed pipe; 102. Exhaust pipe; 103. Discharge pipe; 201. Drive rod; 202. Radial stirring paddle; 203. Axial dispersing wheel; 2031. Dispersing plate; 2032. Guide hole; 204. Spiral slag discharge paddle; 205. Cross-shaped impeller; 206. Wall scraper; 2061. Scraper; 207. Variable frequency motor; 3. Electric valve. Detailed Implementation

[0021] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0022] Reference Figures 1-4 A causticizing reactor is provided, comprising a reactor body 1 and an external heat exchange system. The external heat exchange system is existing technology and will not be described in detail here. The reactor body 1 adopts a double-layer design, with an inner wall of 316L stainless steel and an outer wall of carbon steel insulation. The top of the reactor body 1 is equipped with a connected feed pipe 101 and an exhaust pipe 102. The feed pipe 101 is divided into two branches: a high-level pipe for injecting clear liquid and a side-wall pipe for injecting lime slurry to avoid initial sedimentation. The exhaust pipe 102 is equipped with a pressure safety valve. The bottom of the reactor body 1 is equipped with a connected discharge pipe 103. The reactor also includes: The stirring mechanism includes a drive rod 201 that is perpendicular to and rotatably mounted on the vessel body 1. A multi-stage combined stirrer is mounted on the outer surface of the drive rod 201. The multi-stage combined stirrer includes a wall scraper 206, a radial stirring paddle 202, and an axial dispersing wheel 203 arranged sequentially from top to bottom on the drive rod 201. The drive rod 201 is driven by a drive component. In application, layered stirring is achieved by setting up a multi-stage combined stirrer composed of the wall scraper 206, the radial stirring paddle 202, and the axial dispersing wheel 203. The wall scraper 206 prevents scaling on the vessel wall of the vessel body 1, the radial stirring paddle 202 enhances horizontal mixing, and the axial dispersing wheel 203 promotes vertical flow and eliminates stirring dead zones to improve the mixing efficiency of reactants, especially lime slurry and clear liquid with large density differences. The slag discharge structure includes a spiral slag discharge paddle 204 installed on one end of the drive rod 201. The rotation of the spiral slag discharge paddle 204 is synchronized with the drive rod 201. In application, dynamic slag discharge is achieved by the synchronous design of the spiral slag discharge paddle 204 and the drive rod 201, which avoids sedimentation and blockage, shortens the slag discharge time and reduces residue.

[0023] Reference Figure 2 and Figure 3 The bottom of the vessel body 1 is an inverted conical structure (the cone angle is designed to be 35°). The inner wall of the cone bottom is polished, Ra≤0.4μm, which reduces particle adhesion. The cone angle of the inverted conical structure matches the guide angle of the spiral slag discharge impeller 204. In application, the geometric matching between the inverted conical bottom of the vessel and the spiral slag discharge impeller 204 forms a continuous flow channel, which significantly improves the efficiency of sediment sliding and prevents slag discharge blockage.

[0024] Reference Figure 2 and Figure 3 The scraping wheel 206 is mounted on the drive rod 201 via the cross 205, and the bottom of the scraping wheel 206 is equipped with scrapers 2061 arranged in a circular array. The scrapers 2061 are in close contact with the inner wall of the vessel body 1. The scrapers 2061 are made of flexible material and are polytetrafluoroethylene scrapers, with a tolerance of ±2mm when fitting the vessel wall. In application, the circular array of scrapers 2061 is installed on the cross 205 to expand the scraping coverage area and avoid local material adhesion. It also cooperates with the flexible scrapers 2061 and fits tightly against the vessel wall to adapt to minor deformations of the inner wall, reduce wear, and achieve more thorough cleaning.

[0025] Reference Figure 3 and Figure 4The axial dispersion wheel 203 has dispersion plates 2031 arranged in a circumferential array and staggered vertically. The axial dispersion wheel 203 also has guide holes 2032 arranged in a circumferential array and tilted vertically. The tilt angle of the guide holes 2032 is 5°-10° and the tilt direction of the guide holes 2032 is downward. The diameter of the guide holes 2032 is 50mm and tilted downward at 8°. In application, the staggered dispersion plates 2031 and the tilted guide holes 2032 work together. The dispersion plates 2031 cut large particle clumps, and the guide holes 2032 (tilted downward at 5°-10°) form a downward vortex, which pushes the bottom sediment to resuspend, accelerates the reaction and prevents the deposition of fine calcium carbonate particles.

[0026] Reference Figures 1-3 The driving component is a variable frequency motor 207 with a power of 5.5kW and an adjustable speed range of 0-200rpm. The variable frequency motor 207 is installed on the top of the vessel body 1, and the output shaft of the variable frequency motor 207 is connected to one end of the drive rod 201. In application, the variable frequency motor 207 can adjust the speed according to the reaction stage (such as high speed during the mixing period and low speed during the slag discharge period) to optimize energy consumption and process adaptability.

[0027] Reference Figure 1 and Figure 2 An electric valve 3 is installed on the discharge pipe 103 to control the slag discharge flow rate. In application, the speed control design of the electric valve 3 can accurately adjust the slag discharge flow rate, avoid instantaneous overload blockage of the pipeline, and achieve controllable discharge.

[0028] The working principle of this utility model is as follows: Feeding and reaction start-up stage: Open the clear liquid feed pipe 101 and inject 80% volume of sodium carbonate clear liquid. Then start the variable frequency motor 207 to low speed (50 rpm) and inject lime slurry simultaneously to avoid precipitation and accumulation. Finally, mix and react. At this time, the speed of the variable frequency motor 207 increases to 120 rpm. The multi-stage combined agitator works in coordination. The wall scraper 206 removes the scale on the wall surface. The radial stirring paddle 202 achieves horizontal diffusion. The guide hole 2032 on the axial dispersion wheel 203 forms a downward vortex, which pushes the lime slurry particles to suspension. During this period, the reaction temperature is maintained at 80±5℃ for 40 minutes using an external heat exchange system. Sedimentation and slag removal stage: After stirring is stopped, let it stand for a period of time to allow calcium carbonate to precipitate to the bottom of the cone. Then, start the variable frequency motor 207 to low speed (30 rpm), and the spiral slag discharge paddle 204 rotates to push the sediment. At the same time, the electric valve 3 is opened to 40% to control the slag discharge flow rate at 0.5 m³ / h to avoid pipe blockage. Finally, after slag discharge, clean water is injected, and the speed is increased to 80 rpm. The wall scraper 206 and the axial dispersion wheel 203 work together to flush the inner wall for a period of time (e.g., 10 minutes). Product collection and equipment maintenance stage: Open the discharge pipe 103 to collect the causticizing liquid (sodium hydroxide solution), then regularly check the wear of the scraper 2061, and calibrate the gap of the spiral slag discharge impeller 204 monthly.

[0029] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A causticizing reactor, comprising a reactor body (1), wherein a feed pipe (101) and an exhaust pipe (102) are connected at the top of the reactor body (1), and a discharge pipe (103) is connected at the bottom of the reactor body (1), characterized in that: Also includes: The stirring mechanism includes a drive rod (201) that is perpendicular to and rotatably mounted on the vessel body (1). A multi-stage combined stirrer is mounted on the outer surface of the drive rod (201). The multi-stage combined stirrer includes a wall scraping wheel (206), a radial stirring paddle (202), and an axial dispersing wheel (203) arranged sequentially from top to bottom on the drive rod (201). The drive rod (201) is driven by a driving component. The slag discharge structure includes a spiral slag discharge paddle (204) installed on one end of the drive rod (201), and the rotation of the spiral slag discharge paddle (204) is synchronized with the drive rod (201).

2. The causticizing reactor according to claim 1, characterized in that: The bottom of the vessel body (1) is an inverted conical structure, and the cone angle of the inverted conical structure matches the guide angle of the spiral slag discharge impeller (204).

3. The causticizing reactor according to claim 1, characterized in that: The scraping wheel (206) is mounted on the drive rod (201) via a cross (205), and scrapers (2061) arranged in a circular array are mounted on the bottom of the scraping wheel (206), and the scrapers (2061) are in close contact with the inner wall of the vessel body (1).

4. The causticizing reactor according to claim 3, characterized in that: The scraper (2061) is made of a flexible material.

5. The causticizing reactor according to claim 1, characterized in that: The axial dispersion wheel (203) has dispersion plates (2031) arranged in a circumferential array and staggered vertically, and the axial dispersion wheel (203) has guide holes (2032) arranged in a circumferential array and inclined.

6. The causticizing reactor according to claim 5, characterized in that: The guide hole (2032) has an inclination angle of 5°-10°, and the inclination direction of the guide hole (2032) is downward.

7. The causticizing reactor according to claim 1, characterized in that: The driving component is a variable frequency motor (207), which is installed on the top of the vessel body (1), and the output shaft of the variable frequency motor (207) is connected to one end of the driving rod (201).

8. The causticizing reactor according to any one of claims 1-7, characterized in that: An electric valve (3) for controlling the slag discharge flow rate is installed on the discharge pipe (103).

Images