A white liquor oxidizer

Abstract

The utility model discloses a kind of white liquid oxidizers, including cavity containing cylinder, its characterized in that, cylinder is sequentially provided with top seat, first section packing chamber, second section packing chamber, reducing section, oxidized white liquid storage tank and apron from top to bottom, the top end and lower part of the first section packing chamber and second section packing chamber are respectively provided with white liquid distributor and tray;The top of the oxidized white liquid storage tank is provided with cooling after oxidized white liquid input pipe and oxygen input pipe, bottom is provided with anti-vortex device and is externally connected with oxidized white liquid circulation outlet pipe.By setting white liquid distributor and tray can make white liquid distribution more uniform, more convenient to overhaul, and make white liquid and oxygen reaction fully, improve efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of pulp and paper making, and specifically relates to a white liquor oxidizer. Background Technology

[0002] In modern bleached sulfate pulp production systems, an oxidative white liquor preparation system is often included. This system typically employs an oxygen delignification process. This process involves high-temperature cooking, using oxygen and alkali to treat medium- or high-concentration pulp in one or more stages to further remove residual lignin, effectively achieving a bleaching effect. Oxygen delignification is a processing stage between cooking and bleaching. It refers to the single- or multi-stage oxygen-alkali treatment of medium- or high-concentration pulp under high temperature and pressure conditions, further removing residual lignin. It is a continuation of cooking, and other chemicals can be added during this process to improve fiber whiteness or protect fiber strength.

[0003] Modern white liquor oxidation systems generally use oxidized white liquor instead of purchased alkali, reducing alkali costs and allowing for better control of the alkali balance in the production system. The main function of the white liquor oxidizer is to convert sodium sulfide (Na₂S) in the white liquor into sodium hydroxide (NaOH) and sodium thiosulfate (Na₂S₂O₃) through an oxidation reaction, thereby improving the recovery rate of the white liquor and reducing production costs. There are two main preparation methods for white liquor oxidizers: air oxidation and pure oxygen oxidation. In the pure oxygen oxidation method, a packed tower is typically installed in the reactor. White liquor is sprayed from the top, and oxygen flows upward from the bottom. The two react in a gas-liquid phase. Heat is released during the reaction, generating steam, which increases the pressure and temperature inside the reactor. The operating temperature is generally controlled between 130℃ and 150℃, and the pressure is below 0.6 MPa.

[0004] However, current technology suffers from several drawbacks. The white liquor distributor generates a large amount of foam during distribution, which occupies a significant portion of the packed tower's internal space, drastically reducing the effective volume available for gas-liquid reactions and lowering the tower's throughput. The foam layer covering the packing and liquid surfaces hinders the dissolution and transfer of pure oxygen into the white liquor. Excessive foam accumulation within the tower causes a sharp increase in pressure drop, impeding normal gas and liquid flow. Furthermore, the large amount of foam makes the measurement and control of critical process parameters such as level, pressure, and temperature difficult and inaccurate. For example, foam may mislead level gauge readings, leading to operational errors.

[0005] In addition, when oxygen enters the packed tower, the ratio of the total cross-sectional area of ​​the openings in the oxygen distribution trays to the cross-sectional area of ​​the tower body is relatively low, resulting in high oxygen resistance and uneven oxygen distribution. Utility Model Content

[0006] The purpose of this invention is to provide a white liquor oxidizer that eliminates foam generated during white liquor distribution, ensures uniform distribution of white liquor and oxygen, and allows oxygen and white liquor to react fully, thereby improving reaction efficiency.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows: a white liquor oxidizer, comprising a cylindrical body with a cavity, wherein the cylindrical body is provided with a top seat, a first-section packing chamber, a second-section packing chamber, a variable-diameter section, an oxidized white liquor storage tank, and a skirt seat from top to bottom; a white liquor distributor and a tray are respectively provided at the top and bottom of the first-section packing chamber and the second-section packing chamber; the top of the oxidized white liquor storage tank is provided with a cooled oxidized white liquor inlet pipe and an oxygen inlet pipe, and the bottom is provided with an anti-vortex device and connected to an external oxidized white liquor circulation outlet pipe;

[0008] The white liquor distributor includes a support plate and a white liquor inlet pipe. The support plate is annular and is attached to the periphery of the first / second packing chamber. The distribution plate is fixedly connected to the support plate with bolts. The white liquor inlet pipe is located above the distribution plate. A cross-shaped support member and the support pipe are connected sequentially at the bottom of the white liquor inlet pipe. The support pipe is located above the distribution plate, and the two do not contact each other. At least four demister blocks are also provided above the distribution plate. The demister blocks are symmetrically arranged along the center line of the distribution plate and around the support pipe. The tray has through holes evenly distributed.

[0009] The demister block is a cube made of gas-liquid filter mesh material, with its top end higher than the bottom end of the white liquid inlet pipe.

[0010] The top seat has three holes at its upper end, with an oxygen circulation outlet, an exhaust port, and a safety valve at each hole. A manhole is located on one side of the top seat, and a pressure gauge and a level gauge are located on the other side. The pressure gauge is located above the level gauge, and the white liquid inlet pipe of the white liquid distributor passes through the top seat.

[0011] The first section of the packing chamber is also symmetrically equipped with shaft-type lifting lugs on both the left and right sides. A manhole is provided on one side of the first section of the packing chamber, and the manhole is on the same side as the manhole on the top seat.

[0012] A manhole is provided on one side of the second section of the packing chamber, on the same side as the manhole on the top seat, and the manhole is located above the tray.

[0013] Manholes and thermometers are respectively provided on the left and right sides of the cylinder between the first and second packing chambers, and the white liquor inlet pipe of the white liquor distributor at the top of the second packing chamber extends out from one side of the cylinder.

[0014] The tray includes a support ring and support plates. The support ring is attached to the periphery of the first / second packing chamber. The support plates are installed on the support ring and are beam-shaped gas-jet packing support plates. They are divided into at least two first bent plates placed on the support ring and several second bent plates between the two first bent plates. The two first bent plates have the same shape and are symmetrically arranged relative to the center line of the support ring. Each first bent plate includes a first arch foot and a second arch foot and an arch between them. The first arch foot is constructed into an arc shape that matches the shape of the support ring. The second arch foot is constructed into a straight edge. The edge of the arch adjacent to the support ring is constructed into an arc shape that matches the shape of the support ring. Each second bent plate includes two second arch feet and an arch between them. The edge of the arch adjacent to the support ring is constructed into an arc shape that matches the shape of the support ring.

[0015] The sum of the areas of all the through holes on the tray is equal to the cross-sectional area of ​​the first / second packing chamber.

[0016] The variable diameter section is constructed as a conical cavity that gradually expands from top to bottom towards the oxidized white liquor storage tank. An oxidized white liquor circulation inlet and a level gauge are respectively provided on both sides of the cavity. A white liquor inlet and a thermometer are respectively provided on the left and right sides of the cylinder between the second section packing chamber and the variable diameter section.

[0017] A manhole is provided on the lower part of one side of the oxidized white liquor storage tank, and a thermometer and a level gauge are provided on the other side; a cooled oxidized white liquor inlet pipe and an oxygen inlet pipe are provided on the top of the oxidized white liquor storage tank.

[0018] The upper part of the skirt base is provided with 4 vent holes; the lower part is provided with 2 inspection holes and 1 outlet pipe, and the bottom of the skirt base is also provided with tail lugs.

[0019] The oxygen input pipe consists of an inlet connector, an oxygen distribution pipe, a clamp, and a support platform; the inlet connector is connected to the cylinder; one end of the oxygen distribution pipe is connected to the flange of the inlet connector, and the other end is placed on the support platform; the clamp restricts the oxygen distribution pipe on the support platform; at least three through holes are evenly distributed on the lower semicircular tube of the oxygen distribution pipe.

[0020] Beneficial effects:

[0021] (1) The white liquor distributor improves the uniform distribution of white liquor and reduces foam in the packing chamber, thereby improving the reaction efficiency of the white liquor oxidizer and enabling the white liquor to react fully with oxygen. The white liquor oxidizer storage tank is used to store the white liquor oxidizer and, when necessary, allows the white liquor with unqualified alkali concentration to be circulated and oxidized again, which can better control the alkali balance of the production system.

[0022] (2) The defoaming block of the white liquor distributor can effectively reduce the foam generated during the gas-liquid two-phase exchange, and the tray can make the oxygen distribution more uniform, promoting the dissolution and transfer of pure oxygen into the white liquor.

[0023] (3) A small hole is opened at the bottom of the oxygen input pipe to make the oxygen inlet evenly distributed, reduce the oxygen pressure drop at the inlet, and prevent the white liquid from flowing into the oxygen input pipe when it falls freely. The ratio of the total cross-sectional area of ​​the tray openings to the cross-sectional area of ​​the tower body is increased, which increases the contact time between oxygen and white liquid, so that the white liquid and oxygen react fully, improve the reaction efficiency, reduce oxygen loss, and make maintenance and replacement of parts simpler. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0025] Figure 2 This is a schematic diagram of the white liquor distributor of this utility model;

[0026] Figure 3 This is a top view of the white liquid distributor of this utility model;

[0027] Figure 4 This is a schematic diagram of the tower tray structure of this utility model;

[0028] Figure 5 This is a top view of the tower tray of this utility model;

[0029] Figure 6 This is a schematic diagram of the oxygen input pipe structure of this utility model. Detailed Implementation

[0030] like Figure 1-6 As shown, a white liquor oxidizer includes a cylindrical body containing a cavity, wherein the cylindrical body is provided with a top seat 1, a first packing chamber 2, a second packing chamber 3, a variable diameter section 4, an oxidized white liquor storage tank 5, and a skirt seat 6 from top to bottom.

[0031] Furthermore, the top seat 1 has three holes at its upper end, with an oxygen circulation outlet 101, an exhaust port 102, and a safety valve 103 provided at the holes; a manhole 9a is provided on one side of the top seat 1, and a pressure gauge 11 and a level gauge 12a are provided on the other side, with the pressure gauge 11 located above the level gauge 12a.

[0032] Furthermore, a white liquor distributor 7 and a tray 8 are respectively provided at the top and bottom of the first section of the packing chamber 2. The tray 8 is filled with packing. Shaft-type lifting lugs 201 are symmetrically arranged on the left and right sides of the first section of the packing chamber 2. A manhole 9b is provided on one side of the first section of the packing chamber 2. The manhole 9b is on the same side as the manhole 9a of the top seat 1.

[0033] The white liquor distributor 7 includes a support plate 71 and a white liquor inlet pipe 72. The support plate 71 is annular and is attached to the periphery of the first / second packing chamber. The distribution plate 73 is fixedly connected to the support plate 71 by bolts. The white liquor inlet pipe 72 is located above the distribution plate 73. A cross support member 75 and a support pipe 74 are connected sequentially to the bottom of the white liquor inlet pipe 72. The support pipe 74 is located above the distribution plate 73 and the two do not contact each other. At least four defoaming blocks 76 are also provided above the distribution plate 73. The defoaming blocks 76 are symmetrically arranged along the center line of the distribution plate 73 and around the support pipe.

[0034] The white liquor inlet pipe 72 of the white liquor distributor 7 at the top of the second section packing chamber 2 extends from the side of the top seat 1.

[0035] Preferably, in this embodiment, the distribution plate is a circular plate formed by fixing four distribution plates 73a to 73d to the support plate 71 with bolts. The defoaming block 76 is a cube made of gas-liquid filter mesh material with a mesh size of about 1mm. The top of the defoaming block 76 is higher than the bottom of the white liquid inlet pipe 72.

[0036] Furthermore, the tray 8 includes a support ring 81 and a support plate 82. The support ring 81 is attached to the periphery of the first / second packing chamber, and the support plate 82 is installed on the support ring 81. The support plate 82 is a beam-shaped gas-jet packing support plate, consisting of at least two first bent plates 82a placed on the support ring 81 and several second bent plates 82b between the two first bent plates 82a. The two first bent plates 82a have the same shape and are symmetrically arranged relative to the centerline of the support ring 81, each including a first arch. The second bent plate 82b includes two second arched feet 822 and an arch 823 between them. The first arched foot 821 is constructed in an arc shape that matches the shape of the support ring 81. The second arched foot 822 is constructed with a straight edge. The edge of the arch 823 adjacent to the support ring 81 is constructed in an arc shape that matches the shape of the support ring 81. The second bent plate 82b also includes two second arched feet 822 and an arch 823 between them. The edge of the arch 823 adjacent to the support ring 81 is constructed in an arc shape that matches the shape of the support ring 81. The sum of the areas of all the through holes on the tray 8 is equal to the cross-sectional area of ​​the first / second packing chamber. The support plate 82 is arched, which keeps the packing in the packing chamber away from the through holes on the support plate 82, avoiding obstruction of the oxygen flow channel. The arched support plate 82 increases the surface area, so that the ratio of the total cross-sectional area of ​​the tray openings to the cross-sectional area of ​​the tower body can be close to 1, thereby not hindering the oxygen flow and uniformly distributing the oxygen into the packing.

[0037] Furthermore, the tray 8 of the second section packing chamber 3 is filled with packing, and a manhole 9d is provided on one side of the second section packing chamber 2, on the same side as the manhole 9a of the top seat 1, and the manhole 9d is located above the tray.

[0038] Furthermore, a manhole 9c and a thermometer 13a are respectively provided on the left and right sides of the cylinder between the first section packing chamber 2 and the second section packing chamber 3, and the white liquid inlet pipe 72 of the white liquid distributor 7 at the top of the second section packing chamber 3 extends out from one side of the cylinder.

[0039] The variable diameter section 4 is constructed as a tapered cavity that gradually expands from the second section packing chamber 3 to the oxidized white liquor storage tank 5; an oxidized white liquor circulation inlet 401 and a level gauge 402 are respectively provided on both sides of the variable diameter section 4, and a white liquor inlet 14 and a thermometer 13b are respectively provided on the left and right sides of the cylinder between the second section packing chamber 3 and the variable diameter section 4.

[0040] Furthermore, the top of the oxidized white liquor storage tank 5 is provided with a cooled oxidized white liquor inlet pipe 501 and an oxygen inlet pipe 502, and the bottom opening is provided with an anti-vortex device 503 and connected to an external oxidized white liquor circulation outlet pipe 504. A manhole 9e is also provided on the lower part of one side of the oxidized white liquor storage tank 5, and a thermometer 13c and a liquid level gauge 12b are provided on the other side; the cooled oxidized white liquor inlet pipe 501 and the oxygen inlet pipe 502 are provided on the top of the oxidized white liquor storage tank 5.

[0041] Furthermore, the upper part of the skirt base 6 is provided with four exhaust holes 601; the lower part is provided with two inspection holes 602 and one outlet pipe 603; and the bottom of the skirt base 6 is also provided with a tail lug 604.

[0042] Furthermore, the oxygen input pipe 502 is composed of an inlet pipe 5021, an oxygen distribution pipe 5022, a clamp 5023, and a support platform 5024; the inlet pipe 5021 is welded to the cylinder body; the oxygen distribution pipe 5022 is connected to the flange of one end of the inlet pipe 5021, and the other end is placed on the support platform 5024; the clamp 5023 restricts the oxygen distribution pipe 5022 on the support platform 5024 and is fastened with a nut; the support platform 5024 is welded to the cylinder body.

[0043] The oxygen distribution pipe 5022 has three through holes 5022a evenly distributed on the equidistant multiple cross sections on the lower semicircular pipe. One through hole is vertically downward, and the other two openings on the cross section form an angle of 45° with the vertically downward opening direction.

[0044] When preparing oxidized white liquor using the white liquor oxidizer of this invention, the oxidized white liquor is sprayed from the top of the first and second packed chambers, and then defoamed and evenly distributed on the packing by the white liquor distributor. Oxygen enters from the bottom of the variable diameter section and flows upward, being evenly dispersed into the packing through the support plates of the tray. The two react in a gas-liquid phase. The oxidized white liquor is stored in the oxidized white liquor storage tank 5. If the liquid level reaches the level gauge 402, it is transported to the external oxidized white liquor storage tank through the oxidized white liquor circulation outlet pipe 504. If the oxidized white liquor in the oxidized white liquor storage tank 5 is substandard, it is discharged through the oxidized white liquor circulation outlet pipe 504 and then re-enters the white liquor oxidizer through the oxidized white liquor circulation inlet 401 for oxidation reaction. If the oxidized white liquor in the external oxidized white liquor storage tank needs to be reused after cooling, it is returned to the oxidized white liquor storage tank 5 through the cooled oxidized white liquor inlet pipe 501. The temperature inside the oxidized white liquor storage tank 5 is high, which can reheat the oxidized white liquor in the external oxidized white liquor storage tank.

[0045] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. A white liquor oxidizer, comprising a cylindrical body with a cavity, characterized in that, The cylinder is provided with a top seat (1), a first-section packing chamber (2), a second-section packing chamber (3), a variable diameter section (4), an oxidized white liquor storage tank (5), and a skirt seat (6) from top to bottom. The top and bottom of the first-section packing chamber (2) and the second-section packing chamber (3) are respectively provided with a white liquor distributor (7) and a tray (8). The top of the oxidized white liquor storage tank (5) is provided with a cooled oxidized white liquor inlet pipe (501) and an oxygen inlet pipe (502), and the bottom is provided with an anti-vortex device (503) and connected to an external oxidized white liquor circulation outlet pipe (504). The white liquor distributor (7) includes a support plate (71) and a white liquor inlet pipe (72). The support plate (71) is annular and is attached to the periphery of the first / second packing chamber. The distribution plate (73) is fixedly connected to the support plate (71) by bolts. The white liquor inlet pipe (72) is located above the distribution plate (73). The bottom of the white liquor inlet pipe (72) is connected to a cross support member (75) and a support pipe (74) from top to bottom. The support pipe (74) is located above the distribution plate (73) and the two do not contact each other. At least four demister blocks (76) are also provided above the distribution plate (73). The demister blocks (76) are symmetrically arranged along the center line of the distribution plate (73) and around the support pipe (74). The tray (8) is evenly distributed with through holes.

2. The white liquor oxidizer according to claim 1, characterized in that, The demister block (76) is a cube made of gas-liquid filter mesh material, and the top of the demister block (76) is higher than the bottom of the white liquid inlet pipe (72).

3. A white liquor oxidizer according to claim 1, characterized in that, The top seat (1) has three holes at its upper end, and an oxygen circulation outlet (101), an exhaust port (102), and a safety valve (103) are provided at the openings.

4. A white liquor oxidizer according to claim 1, characterized in that, The tray (8) includes a support ring (81) and a support plate (82). The support ring (81) is attached to the periphery of the first / second packing chamber. The support plate (82) is installed on the support ring (81). The support plate (82) is a beam-shaped gas-jet packing support plate, consisting of at least two first bent plates (82a) placed on the support ring (81) and several second bent plates (82b) between the two first bent plates (82a). The two first bent plates (82a) are identical in shape and symmetrically arranged relative to the centerline of the support ring (81). Each first bent plate (82a) includes a first arch foot (82b). 21) The second arch foot (822) and the arch (823) between them, the first arch foot (821) is constructed to be an arc shape adapted to the shape of the support ring (81), the second arch foot (822) is constructed to have a straight edge, the edge of the arch (823) adjacent to the support ring (81) is constructed to be an arc shape adapted to the shape of the support ring (81), and the second bent plate (82b) includes two second arch feet (822) and the arch (823) between them, the edge of the arch (823) adjacent to the support ring (81) is constructed to be an arc shape adapted to the shape of the support ring (81).

5. A white liquor oxidizer according to claim 1, characterized in that, The sum of the areas of all the through holes on the tray (8) is equal to the cross-sectional area of ​​the first / second packing chamber.

6. A white liquor oxidizer according to claim 1, characterized in that, The variable diameter section (4) is constructed as a cone-shaped cavity that gradually expands from top to bottom. An oxidation white liquor circulation inlet (401) and a level gauge (402) are respectively provided on both sides of the cavity. A white liquor inlet (14) and a thermometer (13b) are respectively provided on the left and right sides of the cylinder between the second section packing chamber (3) and the variable diameter section (4).

7. A white liquor oxidizer according to claim 1, characterized in that, The top of the oxidized white liquor storage tank (5) is equipped with a cooled oxidized white liquor inlet pipe (501) and an oxygen inlet pipe (502).

8. A white liquor oxidizer according to claim 1, characterized in that, The skirt base (6) is provided with multiple vent holes (601) on the upper part; and inspection holes (602) and outlet pipes (603) are provided on the lower part.

9. A white liquor oxidizer according to claim 8, characterized in that, The oxygen input pipe (502) consists of an inlet pipe (5021), an oxygen distribution pipe (5022), a clamp (5023), and a support platform (5024); the inlet pipe (5021) is connected to the cylinder; one end of the oxygen distribution pipe (5022) is connected to the flange of the inlet pipe (5021), and the other end is placed on the support platform (5024); the clamp (5023) restricts the oxygen distribution pipe (5022) on the support platform (5024); at least three through holes are evenly distributed on the lower semicircular tube of the oxygen distribution pipe (5022).

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