Bottom-in and top-out kettle type continuous nitration reactor and pulp continuous esterification process

Abstract

The invention discloses a bottom-in and top-out kettle type continuous nitration reactor and a pulp continuous esterification process, relates to the field of explosive and powder production, and solves the problems of long granular material nitration time and poor product uniformity of the existing nitration reactor. The technical scheme is that the bottom-in and top-out kettle type continuous nitration reactor comprises a reaction kettle and a rotating shaft, the reaction kettle comprises a kettle body and an upper cover, a discharge port is formed in the upper portion of the side wall of the kettle body, a feed port is formed in the lower portion of the side wall of the kettle body, the rotating shaft is rotationally installed at the center of the upper cover, and a bottom stirring device used for enabling materials to mainly flow in the radial direction and secondarily flow in the vertical direction is arranged at the position, corresponding to the feed port, of the rotating shaft. A top-layer stirring device used for enabling materials to flow outwards in the radial direction is arranged at the position, corresponding to the discharging port, of the rotating shaft, and a middle-layer stirring device used for enabling the materials to mainly flow upwards in the vertical direction and secondarily flow outwards in the radial direction is further arranged at the position, between the top-layer stirring device and the bottom-layer stirring device, of the rotating shaft. The device and the method are used for nitration of granular materials.

Description

Technical Field

[0001] The invention relates to a chemical or physical method and related equipment, in particular to the field of explosive production, specifically to a kettle-type continuous nitration reactor and an esterification process using pulp as raw material. Background Art

[0002] Nitrocellulose, also known as nitrocellulose, is the main component of single-base propellants, double-base propellants, triple-base propellants, modified double-base propellants, cross-linked modified double-base propellants, and composite modified double-base propellants. The existing nitration reactor is a U-shaped nitration machine with multiple tubes in series, which is suitable for the preparation of nitrocellulose using flocculent refined cotton as raw material, but not suitable for the preparation of nitrocellulose using granular cellulose as raw material. When using a nitration reactor to nitrate granular cellulose, the material is easy to float to the surface, the nitration reaction time of the material is long, and the material is unevenly distributed in the nitration reactor, resulting in poor product uniformity and other nitration quality problems. Summary of the invention

[0003] The invention firstly solves the problems of long nitration time of granular materials and poor product uniformity in the existing nitration reactor by using a bottom-in and top-out kettle-type continuous nitration reactor.

[0004] The technical scheme adopted by the present invention is: a bottom-in-top-out kettle-type continuous nitration reactor, comprising a reactor and a rotating shaft rotatably installed in the reactor, the reactor comprising a cylindrical reactor body and an upper cover, the reactor body and the upper cover form a closed reaction chamber, the upper part of the side wall of the reactor body is provided with a discharge port, the lower part of the side wall of the reactor body is provided with a feed port, the bottom of the reactor body is provided with an emptying port, the upper cover is provided with a liquid inlet, the rotating shaft is rotatably installed at the center of the upper cover, the center line of the rotating shaft coincides with the center line of the reactor and both are vertical, the rotating shaft is provided with a bottom stirring device for making the material flow mainly in a radial direction and secondarily in a vertical direction at a position corresponding to the feed port, the rotating shaft is provided with a top stirring device for making the material flow radially outward at a position corresponding to the discharge port, and the rotating shaft is also provided with a middle stirring device for making the material flow mainly in a vertical direction upward and secondarily in a radial direction outward between the top stirring device and the bottom stirring device, and there is at least one set of the middle stirring device.

[0005] According to the respective functions of the bottom stirring device, the middle stirring device and the top stirring device, further: the rotation radius of the bottom stirring device and the middle stirring device around the rotation axis is equal, and larger than the rotation radius of the top stirring device around the rotation axis.

[0006] In order to drive the bottom layer stirring device, the middle layer stirring device and the top layer stirring device, further: it also includes a driving device, the upper end of the rotating shaft is located outside the kettle body, and the output shaft of the driving device is in transmission cooperation with the upper end of the rotating shaft.

[0007] The bottom stirring device mainly provides radial flow to disperse the granular material and the mixed acid solution just entering the kettle body, and at the same time has a certain axial flow effect to make the granular material and the mixed acid solution move vertically upward. Specifically: the bottom stirring device includes at least two lower stirring blades fixedly installed on the outer periphery of the lower end of the rotating shaft, the bottom stirring device is centrally symmetrical, and the lower stirring blades are divided into two parts: a strip plate and an arc plate. The angle between the plane corresponding to the strip plate and the horizontal plane is 30° to 60°. One end of the strip plate is directly fixed to the outer periphery of the rotating shaft, and the end of the strip plate away from the rotating shaft is an isosceles acute triangle. The arc plate is connected to the downward waist of the isosceles acute triangle, and the arc plate is located within the cylindrical rotation range of the strip plate around the rotating shaft.

[0008] In order to facilitate the installation of the bottom stirring device, further: the bottom stirring device also includes a lower sleeve, the lower sleeve is fixed to the lower end of the rotating shaft, the lower stirring blade is fixedly installed on the outer periphery of the lower sleeve, and the angle between the plane corresponding to the strip plate of the lower stirring blade and the horizontal plane is 45°.

[0009] The middle stirring device mainly provides axial flow to control the floating speed of granular materials and mixed acid solution, and at the same time has a certain radial flow effect to make the granular materials evenly distributed in the mixed acid solution. Specifically: the middle stirring device includes at least two middle stirring blades fixedly installed on the outer periphery of the rotating shaft, the middle stirring device is centrally symmetrical, the middle stirring blades are in the shape of strips, and the angle between the plane corresponding to the middle stirring blade and the horizontal plane is 30° to 60°.

[0010] In order to facilitate the installation of the middle-layer stirring device, further: the middle-layer stirring device also includes a middle shaft sleeve, the rotating shaft passes through the middle shaft sleeve and the two are relatively fixed, the middle stirring blade is fixedly installed on the outer periphery of the middle shaft sleeve, and the angle between the plane corresponding to the middle stirring blade and the horizontal plane is 45°.

[0011] The top stirring device mainly provides radial flow to push the material floating to the top out of the kettle body. Specifically: the top stirring device includes at least two upper stirring blades fixedly installed on the outer periphery of the rotating shaft. The top stirring device is centrally symmetrical, and the upper stirring blades are in the shape of strips. The angle between the plane corresponding to the upper stirring blade and the horizontal plane is 75° to 90°.

[0012] To facilitate the installation of the top-level stirring device, further: the top-level stirring device also includes an upper shaft sleeve, the rotating shaft passes through the upper shaft sleeve and the two are relatively fixed, the upper stirring blade is fixedly installed on the outer periphery of the upper shaft sleeve, and the angle between the plane corresponding to the upper stirring blade and the horizontal plane is 85°.

[0013] The beneficial effect of the bottom-in-top-out kettle-type continuous nitration reactor of the present invention is that after the granular material is mixed with the mixed acid solution, it enters the kettle body from the feed port at the bottom of the kettle body, and under the joint action of the bottom stirring device and the middle stirring device, the granular material is evenly distributed in the mixed acid solution. The buoyancy of the granular material is greater than the gravity, and the bottom stirring device and the middle stirring device can enable the granular material to overcome most of the buoyancy, thereby intervening in the movement direction and time of the granular material in the horizontal direction and axial direction (that is, the vertical direction), so that the granular material is evenly dispersed in the mixed acid solution; at the same time, the granular material slowly rises in the kettle body, effectively improving the uniformity of the reaction process of the granular material, which is conducive to the esterification to be carried out as fully as possible. After the granular material floats to the top, under the action of the top stirring device, the granular material is further evenly distributed in the mixed acid solution and finally discharged from the discharge port, avoiding the accumulation and decomposition of the granular material at the top, and ensuring the safety of the reaction process. The present invention also has the advantages of simple structure, easy maintenance, and no blockage during the reaction process.

[0014] The present invention also provides a pulp continuous esterification process, the purpose of which is to improve the uniformity of pulp esterification. The technical scheme adopted by the present invention is: the pulp continuous esterification process first slices the rolled pulp, removes the light dust, obtains the granular pulp, then mixes the granular pulp with the mixed acid and infiltrates it, and then feeds it into the feed port of any of the above-mentioned bottom-in and top-out kettle-type continuous nitration reactors, the granular pulp is nitrated in the kettle body, and discharged from the discharge port, and finally the material discharged from the discharge port is acid-driven. The present invention realizes the uniform distribution of the granular pulp during the esterification process, improves the uniformity of the reaction process, and makes the product nitrogen content more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a schematic structural diagram of a bottom-in-top-out kettle-type continuous nitration reactor and an embodiment thereof.

[0016] Figure numerals: reactor 1, discharge port 1-1, feed port 1-2, emptying port 1-3, liquid inlet 1-4, rotating shaft 2, bottom stirring device 3, lower stirring blade 3-1, strip plate 3-1-1, arc plate 3-1-2, lower sleeve 3-2, top stirring device 4, upper stirring blade 4-1, upper sleeve 4-2, middle stirring device 5, middle stirring blade 5-1, middle sleeve 5-2, driving device 6. Figure 1 The circular arrow around the rotating shaft 2 indicates the rotation direction of the rotating shaft 2. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings.

[0018] The first subject of the present invention is a bottom-inlet and top-outlet kettle-type continuous nitration reactor. Figure 1As shown, the bottom-in-top-out kettle-type continuous nitration reactor comprises a reactor 1 and a rotating shaft 2 rotatably mounted in the reactor 1. The reactor 1 comprises a cylindrical kettle body and an upper cover, and the kettle body and the upper cover form a closed reaction chamber. A discharge port 1-1 is provided at the upper part of the side wall of the kettle body, and the discharge port 1-1 is the outlet of the material after the nitration reaction. A feed port 1-2 is provided at the lower part of the side wall of the kettle body, and the feed port 1-2 is the entrance for the material to enter the reactor 1. An emptying port 1-3 is provided at the bottom of the body, and the emptying port 1-3 is used to empty the kettle body. The upper cover is provided with a liquid inlet 1-4, and the liquid inlet 1-4 is used to add a reagent into the kettle body. The rotating shaft 2 is rotatably mounted at the center of the upper cover, and the center line of the rotating shaft 2 coincides with the center line of the reactor 1 and both are vertical. The upper end of the rotating shaft 2 passes through the top of the upper cover, and the lower end of the rotating shaft 2 can be suspended in the kettle body or rotatably connected to the bottom of the kettle body. In order to drive the rotating shaft 2 to rotate around its axis, the bottom-in-top-out kettle-type continuous nitration reactor further includes a driving device 6. The upper end of the rotating shaft 2 is located outside the kettle body, and the output shaft of the driving device 6 is in driving cooperation with the upper end of the rotating shaft 2. The driving device 6 is generally a motor.

[0019] The rotating shaft 2 is provided with a bottom stirring device 3 at a position corresponding to the feed port 1-2, which is used to make the material flow mainly in the radial direction and secondarily in the vertical direction. The height of the bottom stirring device 3 corresponds to the height of the feed port 1-2. The bottom stirring device 3 mainly provides radial flow to disperse the granular material and the mixed acid solution that have just entered the kettle body from the feed port 1-2, and at the same time has a certain axial flow effect to make the granular material and the mixed acid solution move vertically upward. The bottom stirring device 3 includes at least two lower stirring blades 3-1, and each lower stirring blade 3-1 can be directly or indirectly fixedly installed on the rotating shaft 2. For example, the bottom stirring device 3 also includes a lower shaft sleeve 3-2, the lower shaft sleeve 3-2 is fixedly installed on the lower end of the rotating shaft 2, and the lower stirring blade 3-1 is fixedly installed on the outer periphery of the lower shaft sleeve 3-2. The lower stirring blades 3-1 are the same, and the bottom stirring device 3 is centrally symmetrical. The central symmetrical point is the center point of the bottom stirring device 3, and the center point is located on the center line of the rotating shaft 2. There are two or more lower stirring blades 3-1, for example, Figure 1 In the embodiment shown, there are three lower stirring blades 3-1. According to the function of the lower stirring blade 3-1, an embodiment of the lower stirring blade 3-1 is provided below. The lower stirring blade 3-1 is divided into two parts, a strip plate 3-1-1 and an arc plate 3-1-2. Figure 1As shown, the strip plate 3-1-1 is in the shape of a strip plate and the length direction of the strip plate is arranged along the radial direction of the rotating shaft 2. The angle between the plane corresponding to the strip plate 3-1-1 and the horizontal plane is 30° to 60°. For example, the angle between the plane corresponding to the strip plate 3-1-1 of the lower stirring blade 3-1 and the horizontal plane is 45°. One end of the strip plate 3-1-1 is directly fixed to the outer periphery of the rotating shaft 2 or to the outer periphery of the lower sleeve 3-2. The end of the strip plate 3-1-1 away from the rotating shaft 2 is an isosceles acute triangle. The arc plate 3-1-2 is connected to the downward waist of the isosceles acute triangle and the arc plate 3-1-2 is located within the cylindrical rotation range of the strip plate 3-1-1 around the rotating shaft 2. The strip plate 3-1-1 and the arc plate 3-1-2 are smoothly connected, and the strip plate 3-1-1 and the arc plate 3-1-2 are preferably formed as an integral whole.

[0020] The rotating shaft 2 is provided with a top stirring device 4 for making the material flow radially outward at a position corresponding to the discharge port 1-1, and the height of the top stirring device 4 corresponds to the height of the discharge port 1-1. The top stirring device 4 mainly provides radial flow to push the material floating to the top out of the kettle body. The top stirring device 4 includes at least two upper stirring blades 4-1, and each upper stirring blade 4-1 can be directly or indirectly fixedly installed on the rotating shaft 2. For example, the top stirring device 4 also includes an upper sleeve 4-2, the rotating shaft 2 passes through the upper sleeve 4-2 and the two are relatively fixed, the rotating shaft 2 and the upper sleeve 4-2 can be directly welded and fixed or fixed by pins, and the upper stirring blade 4-1 is fixedly installed on the outer periphery of the upper sleeve 4-2, for example, the upper stirring blade 4-1 is welded to the outer periphery of the upper sleeve 4-2 or fixedly installed on the outer periphery of the upper sleeve 4-2 by bolts. Each upper stirring blade 4-1 is the same, and the top stirring device 4 is centrally symmetrical, and the centrally symmetrical point is the center point of the top stirring device 4, and the center point is located on the center line of the rotating shaft 2. The upper stirring blade 4-1 is two or more, for example, Figure 1 In the embodiment shown, there are two upper stirring blades 4-1. The upper stirring blades 4-1 are in the shape of strips, and the plane corresponding to the upper stirring blades 4-1 is vertical or nearly vertical. Generally, the angle between the plane corresponding to the upper stirring blades 4-1 and the horizontal plane is 75° to 90°. For example, the angle between the plane corresponding to the upper stirring blades 4-1 and the horizontal plane is 85°.

[0021] The rotating shaft 2 is also provided with a middle-layer stirring device 5 between the top stirring device 4 and the bottom stirring device 3, which is used to make the material flow upward mainly in the vertical direction and flow outward mainly in the radial direction. The height of the middle-layer stirring device 5 is between the height of the discharge port 1-1 and the height of the feed port 1-2. According to the height difference between the discharge port 1-1 and the feed port 1-2, the middle-layer stirring device 5 can be one set or multiple sets. When there are multiple sets of middle-layer stirring devices 5, each set is arranged at intervals in the vertical direction, and each set is preferably arranged at equal intervals, and the middle stirring blades 5-1 of two adjacent sets are arranged in a staggered manner. The middle-layer stirring device 5 mainly provides axial flow to control the floating speed of the granular material and the mixed acid solution, and at the same time has a certain radial flow effect, so that the granular material is evenly distributed in the mixed acid solution. The middle-layer stirring device 5 includes at least two middle stirring blades 5-1, and each middle stirring blade 5-1 can be directly or indirectly fixedly installed on the rotating shaft 2. For example, the middle stirring device 5 also includes a middle shaft sleeve 5-2, the rotating shaft 2 passes through the middle shaft sleeve 5-2 and the two are relatively fixed, the rotating shaft 2 and the middle shaft sleeve 5-2 can be directly welded and fixed or fixed by pins, and the middle stirring blades 5-1 are fixedly installed on the outer periphery of the middle shaft sleeve 5-2, for example, the middle stirring blades 5-1 are welded to the outer periphery of the middle shaft sleeve 5-2 or fixed to the outer periphery of the middle shaft sleeve 5-2 by bolts. Each middle stirring blade 5-1 is the same, and the middle stirring device 5 is centrally symmetrical, and the central symmetrical point is the center point of the middle stirring device 5, and the center point is located on the center line of the rotating shaft 2. The middle stirring blade 5-1 is in the shape of a strip, and the angle between the plane corresponding to the middle stirring blade 5-1 and the horizontal plane is 30° to 60°, for example, the angle between the plane corresponding to the middle stirring blade 5-1 and the horizontal plane is 45°.

[0022] According to the respective functions of the bottom stirring device 3, the middle stirring device 5 and the top stirring device 4, the rotation radius of the bottom stirring device 3 and the middle stirring device 5 around the rotation axis 2 is equal, and is larger than the rotation radius of the top stirring device 4 around the rotation axis 2, such as Figure 1 The number of the lower stirring blades 3 - 1 of the bottom stirring device 3 is greater than the number of the middle stirring blades 5 - 1 of each set of the middle stirring device 5 , and the number of the lower stirring blades 3 - 1 of the bottom stirring device 3 is also greater than the number of the upper stirring blades 4 - 1 of the top stirring device 4 .

[0023] The second subject of the present invention is a continuous pulp esterification process, the purpose of which is to improve the uniformity of pulp esterification. In the continuous pulp esterification process, the rolled pulp is first sliced ​​to remove light dust to obtain granular pulp; then, the granular pulp is mixed and impregnated with mixed acid; and then fed into the feed port 1-2 of any of the above-mentioned bottom-in and top-out kettle-type continuous nitration reactors, the granular pulp is nitrated in the kettle body and discharged from the discharge port 1-1; finally, the material discharged from the discharge port 1-1 is subjected to acid drive. For example, after the rolled pulp is sliced, it is transported to the dust removal device by the wind conveying device, and the light dust is removed by the dust removal device to obtain granular pulp and enter the silo system; then, the granular pulp is transported to the acid-cotton premixing device through the silo system, the granular pulp is mixed and infiltrated with the mixed acid, and then sent to the feed port 1-2 of the above-mentioned bottom-in and top-out kettle continuous nitration reactor, the granular pulp is nitrated in the kettle body, and discharged from the discharge port 1-1; finally, the material discharged from the discharge port 1-1 enters the acid drive machine for acid drive. Among them, the reaction time of the esterification process is controlled by the mixed acid flow rate, and the reaction temperature of the esterification process is comprehensively controlled by the initial temperature of the mixed acid combined with the reaction heat release.

Claims

1. A bottom-in-top-out kettle-type continuous nitration reactor, comprising a reactor (1) and a rotating shaft (2) rotatably mounted in the reactor (1), wherein the reactor (1) comprises a cylindrical reactor body and an upper cover, wherein the reactor body and the upper cover form a closed reaction chamber, and wherein: The upper part of the side wall of the kettle body is provided with a discharge port (1-1), the lower part of the side wall of the kettle body is provided with a feed port (1-2), the bottom of the kettle body is provided with an emptying port (1-3), the upper cover is provided with a liquid inlet (1-4), the rotating shaft (2) is rotatably mounted at the center of the upper cover, the center line of the rotating shaft (2) coincides with the center line of the reaction kettle (1) and both are vertical, the rotating shaft (2) is provided with a bottom stirring device (3) for making the material flow mainly in a radial direction and secondarily in a vertical direction at a position corresponding to the feed port (1-2), the rotating shaft (2) is provided with a top stirring device (4) for making the material flow radially outward at a position corresponding to the discharge port (1-1), the rotating shaft (2) is also provided with a middle stirring device (5) for making the material flow mainly in a vertical direction upward and secondarily in a radial direction outward between the top stirring device (4) and the bottom stirring device (3), and there is at least one set of the middle stirring device (5).

2. The bottom-in, top-out kettle-type continuous nitration reactor according to claim 1, characterized in that: The rotation radius of the bottom layer stirring device (3) and the middle layer stirring device (5) around the rotation axis (2) is equal, and is greater than the rotation radius of the top layer stirring device (4) around the rotation axis (2).

3. The bottom-in, top-out kettle-type continuous nitration reactor according to claim 1, characterized in that: It also includes a driving device (6), the upper end of the rotating shaft (2) is located outside the kettle body, and the output shaft of the driving device (6) is in transmission cooperation with the upper end of the rotating shaft (2).

4. The bottom-in, top-out kettle-type continuous nitration reactor according to claim 1, 2 or 3, characterized in that: The bottom stirring device (3) comprises at least two lower stirring blades (3-1) fixedly mounted on the outer periphery of the lower end of the rotating shaft (2); the bottom stirring device (3) is centrally symmetrical; the lower stirring blades (3-1) are divided into two parts, namely a strip plate (3-1-1) and an arc plate (3-1-2); the angle between the plane corresponding to the strip plate (3-1-1) and the horizontal plane is 30° to 60°; one end of the strip plate (3-1-1) is directly fixed to the outer periphery of the rotating shaft (2); the end of the strip plate (3-1-1) away from the rotating shaft (2) is in the shape of an isosceles acute triangle; the arc plate (3-1-2) is connected to the downward waist of the isosceles acute triangle; and the arc plate (3-1-2) is located within the cylindrical rotation range of the strip plate (3-1-1) around the rotating shaft (2).

5. The bottom-in, top-out kettle-type continuous nitration reactor as claimed in claim 4, characterized in that: The bottom stirring device (3) also includes a lower shaft sleeve (3-2), the lower shaft sleeve (3-2) is fixed to the lower end of the rotating shaft (2), the lower stirring blade (3-1) is fixedly installed on the outer periphery of the lower shaft sleeve (3-2), and the angle between the plane corresponding to the strip plate (3-1-1) of the lower stirring blade (3-1) and the horizontal plane is 45 degrees.

6. The bottom-in, top-out kettle-type continuous nitration reactor according to claim 1, 2 or 3, characterized in that: The middle stirring device (5) comprises at least two middle stirring blades (5-1) fixedly mounted on the outer periphery of the rotating shaft (2); the middle stirring device (5) is centrally symmetrical; the middle stirring blades (5-1) are in the shape of strips; and the angle between the plane corresponding to the middle stirring blades (5-1) and the horizontal plane is 30° to 60°.

7. The bottom-in, top-out kettle-type continuous nitration reactor according to claim 6, characterized in that: The middle layer stirring device (5) also comprises a middle shaft sleeve (5-2), the rotating shaft (2) passes through the middle shaft sleeve (5-2) and the two are relatively fixed, the middle stirring blade (5-1) is fixedly mounted on the outer periphery of the middle shaft sleeve (5-2), and the angle between the plane corresponding to the middle stirring blade (5-1) and the horizontal plane is 45 degrees.

8. The bottom-in, top-out kettle-type continuous nitration reactor according to claim 1, 2 or 3, characterized in that: The top stirring device (4) comprises at least two upper stirring blades (4-1) fixedly mounted on the outer periphery of the rotating shaft (2); the top stirring device (4) is centrally symmetrical; the upper stirring blades (4-1) are in the shape of strips; and the angle between the plane corresponding to the upper stirring blades (4-1) and the horizontal plane is 75° to 90°.

9. The bottom-in, top-out kettle-type continuous nitration reactor as claimed in claim 8, characterized in that: Top stirring device (4) It also comprises an upper shaft sleeve (4-2), the rotating shaft (2) passes through the upper shaft sleeve (4-2) and the two are relatively fixed, the upper stirring blade (4-1) is fixedly mounted on the outer periphery of the upper shaft sleeve (4-2), and the angle between the plane corresponding to the upper stirring blade (4-1) and the horizontal plane is 85°.

10. A continuous pulp esterification process, characterized in that: The rolled pulp is first sliced ​​to remove light dust to obtain granular pulp, and then the granular pulp is mixed with mixed acid and impregnated, and then fed into the feed port (1-2) of the bottom-in and top-out kettle-type continuous nitration reactor as described in any one of claims 1 to 9 above, the granular pulp is nitrated in the kettle body and discharged from the discharge port (1-1), and finally the material discharged from the discharge port (1-1) is subjected to acid removal.

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