Device for process for efficiently preparing nano lignin from papermaking black liquor

Abstract

The utility model discloses a device for a process for efficiently preparing nano lignin from papermaking black liquor, which belongs to the technical field of lignin extraction, and comprises a reaction kettle, a shear pump and a heating box, the bottom of the reaction kettle is connected with a discharge pipe, and the inlet end of the shear pump is connected with the discharge pipe through a first return pipe; the heating box comprises a containing cavity, a first heater and a coiled pipe, the outlet end of the shear pump is connected with the coiled pipe through a second return pipe, and the coiled pipe is connected with the reaction kettle through a third return pipe. Papermaking black liquor and an added solvent in the reaction kettle are mixed by the shear pump and then returned into the reaction kettle, so that the mixing and dispersing effects are good, and the lignin extraction rate is favorably improved; water in the heating box is used for heating a solution in the coiled pipe, the heating effect on the solution is good, heating is uniform, and excessive heating is avoided. The circulating pump is arranged, so that the solution in the reaction kettle can be circulated under the condition that a shear pump is not used, and the overall application range of the device is wide.

Description

Technical Field

[0001] The utility model belongs to the technical field of lignin extraction, and in particular relates to a device for efficiently preparing nano-lignin from papermaking black liquor. Background Art

[0002] Papermaking black liquor refers to the waste cooking liquor from the sulfate process in the papermaking process. The raw materials such as straw used for papermaking contain three parts: cellulose, lignin and hemicellulose (polysaccharides). Only the cellulose (about 40%) is used for papermaking, while the lignin, which accounts for about 25%, is discarded with the black liquor. The lignin contained in the black liquor has a high utilization value in industrial production. In the existing process of preparing lignin nanoparticles through black liquor, alkali lignin is first prepared from papermaking black liquor, and then the alkali lignin is prepared into lignin colloid, and finally the lignin colloid is treated to obtain lignin nanoparticles. In the process of preparing alkali lignin, black liquor needs to be added to a reactor for heating, and acid is added during stirring to fully react so as to precipitate alkali lignin, and then pure alkali lignin is obtained through filtering, washing, drying and grinding. In the process of preparing lignin colloid, alkali lignin needs to be added to water in the reactor, the water is kept stirred and alkali liquor is added to obtain a lignin solution, the lignin solution and water are mixed evenly, and then an inorganic acid is added dropwise to adjust the pH value of the solution system, and stirring is maintained at the same time, and lignin colloid is formed after standing.

[0003] It can be seen that the heating and mixing effects of the solution are very important in the preparation process of lignin nanoparticles. The black liquor is easily overheated in the existing reaction device, and the solution is mixed only by a stirring paddle during the acid addition and the dropwise addition of inorganic acid, and the mixing effect is poor. The uniform heating of the black liquor and the mixing effect of the solution directly affect the preparation efficiency of lignin nanoparticles. Utility Model Content

[0004] The technical problem solved by the utility model is to provide a device for efficiently preparing nano-lignin from papermaking black liquor, so as to improve the uniformity of heating the black liquor and the mixing effect of the solution.

[0005] Technical solution: In order to solve the above technical problems, the technical solution adopted by the utility model is as follows:

[0006] A device for efficiently preparing nano-lignin from papermaking black liquor comprises a reactor, a shear pump connected to the reactor, and a heating box connected to the shear pump, a discharge pipe is connected to the bottom of the reactor, an inlet end of the shear pump is connected to the discharge pipe through a first reflux pipe, the heating box comprises a containing cavity, a first heater for heating a first medium in the containing cavity, and a serpentine tube arranged in the containing cavity, an outlet end of the shear pump is connected to the serpentine tube through a second reflux pipe, and the serpentine tube is connected to the reactor through a third reflux pipe.

[0007] Preferably, the outer wall of the reactor is connected with a jacket, the jacket contains a second medium, and the jacket is connected with a second heater for heating the second medium.

[0008] Preferably, the first reflux pipe is connected to the circulation pump through a fourth reflux pipe, and the outlet end of the circulation pump is connected to the second reflux pipe through a fifth reflux pipe.

[0009] Preferably, the first return pipe is provided with a first stop valve, the second return pipe is provided with a second stop valve, the fourth return pipe is provided with a third stop valve, and the fifth return pipe is provided with a fourth stop valve.

[0010] Preferably, the reactor is provided with an inner reactor tube connected to the third reflux pipe.

[0011] Preferably, the reactor is provided with a first stirring device.

[0012] Preferably, the reactor is connected to a first temperature sensor, the first reflux pipe is connected to a second temperature sensor, and the third reflux pipe is connected to a third temperature sensor.

[0013] Preferably, a fourth temperature sensor is provided on the heating box.

[0014] Preferably, the reaction kettle and the shear pump are both arranged on a base, the heating box is connected to the base via a bracket, and the circulation pump is connected to the bracket.

[0015] Beneficial effects: Compared with the prior art, the utility model has the following advantages:

[0016] 1. By setting up a reactor, a shear pump and a heating box, the papermaking black liquor and the added solvent in the reactor are mixed by the shear pump and then returned to the reactor, which has a good mixing and dispersion effect and is conducive to improving the lignin extraction rate;

[0017] 2. A jacket is set outside the reactor to heat the solution with water, and a serpentine tube is set inside the heating box. The water in the heating box is used to heat the solution in the serpentine tube, which has a good heating effect on the solution, and the heating is uniform and will not be overheated;

[0018] 3. A circulation pump is provided to circulate the solution in the reactor without using a shear pump, and the overall application range of the device is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present utility model;

[0020] Figure 2 is a schematic diagram of the structure of the return pipe portion of Example 1;

[0021] Figure 3 This is a schematic diagram of the heating box structure of Example 1;

[0022] Figure 4 is a schematic diagram of the overall structure of Example 2; DETAILED DESCRIPTION

[0023] The present invention will be further explained below in conjunction with specific embodiments. The embodiments are implemented based on the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0024] Example 1

[0025] like Figure 1 As shown, a device for efficiently preparing nano-lignin from papermaking black liquor comprises a reactor 1, a shear pump 2, a heating box 3, a circulating pump 6 and a base 9. The base 9 is a rectangular base. The reactor 1 and the shear pump 2 are both arranged on the base 9. The heating box 3 is connected to the base 9 through a bracket 91. The circulating pump 6 is connected to the bracket 91. The reactor 1 is provided with a first stirring device 19. The first stirring device 19 adopts a paddle stirrer to stir the material in the reactor. The outer wall of the reactor 1 is connected to a jacket 4. The jacket 4 contains a second medium. In this embodiment, the second medium adopts water. The jacket 4 is connected to a second heater 41 for heating the second medium. The second heater 41 adopts an existing electric heater. The second heater 41 is connected to the side wall of the jacket 4 and extends to the bottom of the jacket 4. When the second heater 41 is working, it heats the water and thus heats the solution in the reactor 1.

[0026] like Figure 1 , Figure 2 and Figure 3As shown, the reactor 1 is a vertical reactor, and a first functional pipe 11 and a second functional pipe 13 are arranged on the top of the reactor 1. The first functional pipe 11 and the second functional pipe 13 are both arranged at least one, and are used to connect to an external pipeline to put water, papermaking black liquor or other solvents into the reactor 1, or to open a pipeline to put materials. The second functional pipe 13 can also be connected to external equipment such as temperature measurement or pressure measurement. A discharge pipe 12 is connected to the middle position of the bottom of the reactor 1. The inlet end of the shear pump 2 is connected to the discharge pipe 12 through a first reflux pipe 51, and the outlet end of the shear pump 2 is connected to the heating box 3 through a second reflux pipe 52. The heating box 3 is connected to the reactor 1 through a third reflux pipe 53. The shear pump 2 draws out the solution in the reactor 1 through the first reflux pipe 51, and after being heated by the heating box 3, it is returned to the reactor through the third reflux pipe 53. In the kettle 1, the reactor 1 is provided with an inner tube 18 connected to the third reflux pipe 53, the inner tube 18 extends downward to the middle position of the reactor 1, the lower end outlet of the inner tube 18 is close to the liquid surface in the kettle, reducing the drop of the reflux liquid, and the reactor 1 is sheared by the shear pump 2, the shear pump 2 adopts the existing high shear dispersion emulsification pump, the high tangential speed generated by the high-speed rotation of the rotor in the shear pump 2 and the strong kinetic energy brought by the high-frequency mechanical effect make the material in the narrow gap between the stator and the rotor subject to strong mechanical and hydraulic shearing, centrifugal extrusion, liquid layer friction, impact tearing and turbulence, etc., which can make the particle size range as small as nanometer level, and the papermaking black liquor is fully and evenly mixed with the added solvent after passing through the shear pump 2, and the mixing effect is good, and the grinding process of the later soda ash lignin is also reduced after passing through the shear pump 2.

[0027] like Figure 1 , Figure 2 and Figure 3 As shown, the heating box 3 includes a accommodating chamber 31, a first heater 32 and a serpentine tube 33. The accommodating chamber 31 contains a first medium. In this embodiment, the first medium is water. The main body of the serpentine tube 33 is arranged in the accommodating chamber 31. The outlet end of the shear pump 2 is connected to the serpentine tube 33 through the second reflux pipe 52. The outlet end of the serpentine tube 33 is connected to the third reflux pipe 53. The first heater 32 adopts an existing electric heater. When the first heater 32 is working, it heats the water in the accommodating chamber 31 and heats the solution in the serpentine tube 33 through the water. Since the solution is heated indirectly by water, the heating is gentler than the method in which the heater directly contacts the solution, and the solution will not be overheated.

[0028] like Figure 1 and Figure 2As shown, the first reflux pipe 51 is connected to the inlet end of the circulation pump 6 through the fourth reflux pipe 54, and the outlet end of the circulation pump 6 is connected to the second reflux pipe 52 through the fifth reflux pipe 55. The first reflux pipe 51 is provided with a first stop valve 71, the second reflux pipe 52 is provided with a second stop valve 72, the fourth reflux pipe 54 is provided with a third stop valve 73, and the fifth reflux pipe 55 is provided with a fourth stop valve 74. The first stop valve 71 and the second stop valve 72 are closed, and the third stop valve 73 and the fourth stop valve 74 are closed. The solution of the discharge pipe 12 passes through the circulation pump 6 and then enters the heating box 3 and returns to the reactor 1. By setting the circulation pump 6 and multiple stop valves, the shear pump 2 can be short-circuited. When the shear pump 2 is not needed to work, the circulation pump 6 is used to replace it to circulate the solution.

[0029] like Figure 1 and Figure 2 As shown, the reactor 1 is connected with a first temperature sensor 81, which is arranged at the top of the reactor 1 and the temperature measuring head of the first temperature sensor 81 extends downward to the bottom wall of the reactor body, and the first temperature sensor 81 is used to measure the temperature of the solution in the reactor 1. The first reflux pipe 51 is connected with a second temperature sensor 82, which is arranged at one end of the first reflux pipe 51 close to the discharge pipe 12, and the second temperature sensor 82 is used to measure the temperature of the solution coming out of the reactor 1. The third reflux pipe 53 is connected with a third temperature sensor 83, which is arranged at one end of the third reflux pipe 53 close to the reactor 1, and the third temperature sensor 83 is used to measure the temperature of the solution entering the reactor 1. The heating box 3 is provided with a fourth temperature sensor 84, which is used to measure the temperature of the water in the accommodating chamber 31. The temperature of the solution in the reactor 1, the temperature before entering the heating box 3, and the temperature after being heated by the heating box 3 can be mastered through multiple temperature sensors, so as to control the operation of the first heater 32 on the heating box 3 and the second heater 41 on the jacket 4.

[0030] Example 2

[0031] The difference from Example 1 is that the first stirring device 19 of this embodiment adopts a double-disc disperser. Driven by the driving motor, the two dispersion disks rotate at a high linear speed. Under the action of the huge centrifugal force, powerful hydraulic shear and high-frequency mechanical effects are generated, so that the solution in the reactor 1 is subjected to high-frequency shear and mechanical effects, thereby achieving the effect of mixing and dispersing, and the mixing effect is good.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A device for efficiently preparing nano-lignin from papermaking black liquor, characterized in that: The invention comprises a reactor (1), a shear pump (2) connected to the reactor (1), and a heating box (3) connected to the shear pump (2); a discharge pipe (12) is connected to the bottom of the reactor (1); an inlet end of the shear pump (2) is connected to the discharge pipe (12) via a first reflux pipe (51); the heating box (3) comprises a containing chamber (31), a first heater (32) for heating a first medium in the containing chamber (31), and a serpentine pipe (33) arranged in the containing chamber (31); an outlet end of the shear pump (2) is connected to the serpentine pipe (33) via a second reflux pipe (52); and the serpentine pipe (33) is connected to the reactor (1) via a third reflux pipe (53).

2. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 1, characterized in that: The outer wall of the reaction kettle (1) is connected to a jacket (4), a second medium is contained in the jacket (4), and a second heater (41) for heating the second medium is connected to the jacket (4).

3. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 2, characterized in that: The first return pipe (51) is connected to the circulation pump (6) via a fourth return pipe (54), and the outlet end of the circulation pump (6) is connected to the second return pipe (52) via a fifth return pipe (55).

4. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 3, characterized in that: The first return pipe (51) is provided with a first stop valve (71), the second return pipe (52) is provided with a second stop valve (72), the fourth return pipe (54) is provided with a third stop valve (73), and the fifth return pipe (55) is provided with a fourth stop valve (74).

5. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 1, characterized in that: The reactor (1) is provided with an inner reactor tube (18) connected to the third reflux pipe (53).

6. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 1, characterized in that: The reaction kettle (1) is provided with a first stirring device (19).

7. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 1, characterized in that: The reaction kettle (1) is connected to a first temperature sensor (81), the first reflux pipe (51) is connected to a second temperature sensor (82), and the third reflux pipe (53) is connected to a third temperature sensor (83).

8. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 1, characterized in that: The heating box (3) is provided with a fourth temperature sensor (84).

9. The device for efficiently preparing nano-lignin from papermaking black liquor according to claim 3, characterized in that: The reaction kettle (1) and the shear pump (2) are both arranged on a base (9), the heating box (3) is connected to the base (9) via a bracket (91), and the circulation pump (6) is connected to the bracket (91).

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