Processing method of modified starch for papermaking

Abstract

The invention discloses a processing method of modified starch for papermaking, and the processing method comprises the following steps: S1, soaking and cleaning cassava; s2, putting the cleaned cassava into a drying device for surface drying; s3, crushing cassava to obtain cassava slurry; s4, adding acetic anhydride into the starch slurry, and reacting for 40-90 minutes under the conditions that the temperature is 20-35 DEG C and the pH value is 8.2-9.8; s5, adding a protective agent, and reacting for 15-50 minutes under the conditions that the temperature is 32-38 DEG C and the pH value is 7.1-11.9; s6, adding 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, and reacting for 100 to 250 minutes under the conditions that the temperature is 40 to 45 DEG C and the pH (Potential of Hydrogen) is 7.5 to 9.5; s7, performing slurry concentration on the slurry subjected to the mixed reaction by using a concentrator, and dehydrating the concentrated slurry; s6, feeding the dehydrated starch into a drying device for drying; and S7, feeding the dried modified starch into a stock bin of a loading machine, and bagging and packaging. The synthesis steps are relatively simple, and the energy consumption is relatively low.

Description

Technical Field

[0001] The present invention relates to the technical field of modified starch processing, and particularly relates to a method for processing modified starch for papermaking. Background Art

[0002] Modified starch refers to starch that, based on its inherent properties, has its performance improved and its application scope expanded by using physical, chemical, or enzymatic treatments to introduce new functional groups onto the starch molecules or change the starch molecule size and starch granule properties, thereby changing the natural properties of starch (such as: gelatinization temperature, thermal viscosity and its stability, freeze-thaw stability, gel strength, film-forming property, transparency, etc.) to make it more suitable for certain application requirements. This starch that has been processed twice and has its properties changed is collectively referred to as modified starch.

[0003] The purposes of modifying starch: One is to meet the requirements of various industrial applications. For example: high-temperature technology (canned food sterilization) requires good high-temperature viscosity stability of starch, frozen foods require good freeze-thaw stability of starch, jelly foods require good transparency and film-forming property, etc. The other is to develop new uses for starch and expand its application scope. For example: using starch in textiles; using hydroxyethyl starch and hydroxypropyl starch to replace plasma; using highly cross-linked starch to replace talcum powder for surgical gloves, etc.

[0004] Adding modified starch to paper can significantly improve paper strength, has good retention and drainage effects, increases the paper machine speed, reduces the white water concentration, reduces pollution, reduces energy consumption, and reduces breaks during the papermaking process. However, the existing synthesis of modified starch is relatively complex and has high energy consumption. Summary of the Invention

[0005] The problem to be solved by the present invention is: to provide a method for processing modified starch for papermaking with relatively simple synthesis steps and low energy consumption.

[0006] The technical solution provided by the present invention to solve the above problem is: a method for processing modified starch for papermaking, the processing method includes the following steps,

[0007] S1. Soak and wash cassava;

[0008] S2. Put the washed cassava into a drying device for surface drying;

[0009] S3. Crush the cassava to obtain cassava slurry, and use a centrifuge to separate the starch slurry from the cassava slurry;

[0010] S4. Add acetic anhydride to the starch slurry and react for 40 - 90 minutes under the conditions of 20 - 35°C and pH 8.2 - 9.8;

[0011] S5. Add a protective agent and react for 15 - 50 minutes under the conditions of 32 - 38 °C and pH 7.1 - 11.9;

[0012] S6. Add 3 - chloro - 2 - hydroxypropyl - trimethyl ammonium chloride and react for 100 - 250 minutes under the conditions of 40 - 45 °C and pH 7.5 - 9.5;

[0013] S7. Use a thickener to concentrate the slurry after the mixing reaction, and then dehydrate the concentrated slurry;

[0014] S6. Feed the dehydrated starch into a drying device for drying;

[0015] S7. Feed the dried modified starch into the silo of a loading machine for bagging and packing.

[0016] Preferably, the addition amount of acetic anhydride in S4 is 4 - 18% of the mass of starch in the starch slurry.

[0017] Preferably, the protective agent in S5 is sodium chloride.

[0018] Preferably, the addition amount of sodium chloride is 8 - 25% of the mass of starch in the starch slurry.

[0019] Preferably, the addition amount of 3 - chloro - 2 - hydroxypropyl - trimethyl ammonium chloride in S6 is 4 - 15% of the mass of starch in the starch slurry.

[0020] Preferably, the drying device in S6 includes a drying box, a hot - air drying component, and a screen component. The drying box is provided with a feed inlet. The hot - air drying component is installed inside the drying box to dry the modified starch in the drying box. The screen component includes a screening net and a first spring. An installation rod is arranged inside the drying box. One end of the second spring is fixedly connected to the installation rod, and the other end is fixedly connected to the lower end face of the screening net.

[0021] Preferably, the hot - air drying component includes a hot - air generator, a connecting pipe, and a rotating air - outlet mechanism. The hot - air generator is used to generate hot air. One end of the connecting pipe is connected to the hot - air generator, and the other end is rotatably connected to the rotating air - outlet mechanism installed on the drying box. The hot air generated by the hot - air generator enters the rotating air - outlet mechanism through the connecting pipe. The rotating air - outlet mechanism rotates inside the drying box while discharging air to dry the modified starch in the drying box.

[0022] Preferably, the rotating air outlet mechanism includes a motor, a rotating shaft, and a plurality of fixed rods. The motor is installed on one side of the drying box. One end of the rotating shaft is in transmission connection with the motor, and the other end extends into the drying box and is rotatably connected to the connecting pipe. An air inlet flow channel is arranged on the rotating shaft. The plurality of fixed rods are installed on the rotating shaft. An air outlet flow channel communicating with the air inlet flow channel is axially arranged inside the fixed rod. A plurality of air outlet holes communicating with the air outlet flow channel are arranged on the fixed rod.

[0023] Preferably, a shielding component is arranged in the air outlet flow channel. When hot air is introduced into the air outlet flow channel, the shielding component automatically opens to open the air outlet holes, and when the hot air in the air outlet flow channel disappears, the shielding component automatically closes.

[0024] Preferably, the shielding component includes a thermally expandable ring, a shielding pipe, and a second spring. An installation groove for installing the thermally expandable ring is arranged at one end of the air outlet flow channel. The shielding pipe is movably installed in the air outlet flow channel. One end of the second spring is fixedly connected to the bottom of the air outlet flow channel, and the other end is fixedly connected to one end of the shielding pipe away from the thermally expandable ring. A limiting ring for cooperating with and abutting against the thermally expandable ring is arranged at one end of the shielding pipe. A plurality of through holes are arranged on the shielding pipe.

[0025] Compared with the prior art, the advantages of the present invention are as follows: The present invention adopts a one-step esterification-etherification process to produce composite cassava modified starch. A protective agent is added between the first reaction and the second reaction to ensure that the groups in the first reaction do not fall off while connecting different groups in the second reaction and enabling the second reaction to proceed as required. Moreover, the present invention only uses one washing and concentration process to solve the two washing and concentration processes in the general process, which not only saves production time but also greatly saves the consumption of energy such as water and electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0027] Figure 1 is a system flow block diagram of the present invention;

[0028] Figure 2 is a three-dimensional structural schematic diagram of the drying device of the present invention;

[0029] Figure 3 is a cross-sectional view of the drying device of the present invention;

[0030] Figure 4 is Figure 3 an enlarged schematic view of part A in

[0031] Figure 5 is Figure 4Enlarged schematic view at position B in [the figure];

[0032] Figure 6 is a cross-sectional view of the shielding component and the fixing rod of the present invention

[0033] Figure 7 is Figure 6 enlarged schematic view at position C in [the figure].

[0034] Reference numerals in the drawings: 1. Feed inlet, 2. Drying box, 3. Screening mesh, 4. First spring, 5. Mounting rod, 6. Motor, 7. Rotating shaft, 8. Fixing rod, 9. Air outlet hole, 10. Connecting pipe, 11. Second spring, 12. Through hole, 13. Shielding pipe, 14. Thermally expandable ring, 15. Mounting groove, 16. Limiting ring, 17. Air outlet flow channel, 18. Air inlet flow channel. Detailed implementation manners

[0035] The following will describe in detail the implementation manners of the present invention in conjunction with the drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the realization process of technical effects and implement accordingly.

[0036] In the description of the present invention, it should be noted that for orientation terms, such as terms "center", "horizontal", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the orientation and position relationships indicated are based on the orientation or position relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present invention.

[0037] In addition, for terms "first" and "second", they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "several" is two or more, unless otherwise specifically defined.

[0038] In the present invention, unless otherwise clearly specified and limited, for terms such as "assembled", "connected", "joined", they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection; it can be directly connected, or connected through an intermediate medium, and can be internally connected and communicated between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0039] It should be understood that when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0040] It should also be understood that the terms used in the specification of the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present invention. As used in the specification of the embodiments of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0041] Specific embodiments of the present invention are shown in the accompanying drawings. A method for processing modified starch for papermaking, the processing method comprising the following steps:

[0042] S1. Soak and wash the cassava.

[0043] S2. Put the washed cassava into a drying device for surface drying.

[0044] S3. Crush the cassava to obtain cassava slurry, and use a centrifuge to separate the starch slurry from the cassava slurry.

[0045] S4. Add acetic anhydride to the starch slurry and react at 20 - 35 °C and pH 8.2 - 9.8 for 40 - 90 minutes.

[0046] S5. Add a protective agent and react at 32 - 38 °C and pH 7.1 - 11.9 for 15 - 50 minutes.

[0047] S6. Add 3-chloro-2-hydroxypropyltrimethylammonium chloride and react at 40 - 45 °C and pH 7.5 - 9.5 for 100 - 250 minutes.

[0048] S7. Use a concentrator to concentrate the slurry after the mixed reaction, and then dehydrate the concentrated slurry.

[0049] S6. Feed the dehydrated starch into a drying device for drying.

[0050] S7. Feed the dried modified starch into the silo of a bagging machine for bagging and packing.

[0051] Among them, the addition amount of acetic anhydride in S4 is 4 - 18% of the mass of starch in the starch slurry. Specifically, the protective agent in S5 is sodium chloride.

[0052] In this embodiment, the addition amount of sodium chloride is 8-25% of the mass of starch in the starch slurry. Further, the addition amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride in S6 is 4-15% of the mass of starch in the starch slurry.

[0053] In the above solution, a one-step esterification-etherification method is used to produce composite cassava modified starch. A protective agent is added between the first reaction and the second reaction to ensure that the groups in the first reaction do not fall off and different groups in the second reaction can be connected, and the second reaction can proceed as required. Moreover, the present invention only uses one washing and concentration process to solve the two washing and concentration processes in the general process, which not only saves production time but also greatly saves the consumption of energy such as water and electricity.

[0054] As another embodiment of the present invention, the drying device in S6 includes a drying box 2, a hot air drying component and a screen component. The drying box 2 is provided with a feed inlet 1. The hot air drying component is installed in the drying box 2 to dry the modified starch in the drying box 2. The screen component includes a screening net 3 and a first spring 4. An installation rod 5 is arranged inside the drying box 2. One end of the second spring 11 is fixedly connected to the installation rod 5, and the other end is fixedly connected to the lower end surface of the screening net 3. By setting the screening net, the starch on the screening net that is not caked can smoothly fall from the mesh holes of the screening net after drying, while the caked starch remains on the screening net and falls from the mesh holes of the screening net after being thoroughly dried and dispersed, thereby effectively improving the screening efficiency.

[0055] Specifically, the hot air drying component includes a hot air generator, a connecting pipe and a rotating air outlet mechanism. The hot air generator is used to generate hot air. One end of the connecting pipe 10 is connected to the hot air generator, and the other end is rotatably connected to the rotating air outlet mechanism installed on the drying box 2. The hot air generated by the hot air generator enters the rotating air outlet mechanism through the connecting pipe, and the rotating air outlet mechanism rotates in the drying box 2 while discharging air to dry the modified starch in the drying box 2.

[0056] Further, the rotating air outlet mechanism includes a motor 6, a rotating shaft 7 and a plurality of fixing rods 8. The motor 6 is installed on one side of the drying box 2. One end of the rotating shaft 7 is in transmission connection with the motor 6, and the other end extends into the drying box 2 and is rotatably connected to the connecting pipe. An air inlet flow channel 18 is arranged on the rotating shaft 7. A plurality of the fixing rods 8 are installed on the rotating shaft 7. An air outlet flow channel 17 communicated with the air inlet flow channel 18 is axially arranged inside the fixing rod 8, and a plurality of air outlet holes 9 communicated with the air outlet flow channel 17 are arranged on the fixing rod 8.

[0057] In the above solution, during the rotation of the rotating air outlet mechanism, hot air is ejected from the air outlet holes. On the one hand, the hot air is used to stir and dry the starch falling from the screening net, making the drying of the starch more uniform. On the other hand, the fixed rod and the hot air with a relatively high flow rate are used to break up some agglomerated starch, improving the drying effect. Moreover, the hot air ejected during the rotation of the rotating air outlet mechanism is sprayed on the screening net at intervals, which can cause the screening net to vibrate, enabling the screening net to perform vibratory screening, so that the starch can smoothly fall from the screening net.

[0058] Among them, in order to prevent the starch in the drying box from falling into the air outlet flow channel after the hot air generator is turned off, a shielding component is arranged in the air outlet flow channel 17. The shielding component automatically opens to open the air outlet holes 9 when hot air is introduced into the air outlet flow channel 17, and automatically closes when the hot air in the air outlet flow channel 17 disappears. Specifically, the shielding component includes a thermally expandable ring 14, a shielding pipe 13 and a second spring 11. An installation groove 15 for installing the thermally expandable ring 14 is arranged at one end of the air outlet flow channel 17. The shielding pipe 13 is movably installed in the air outlet flow channel 17. One end of the second spring 11 is fixedly connected to the bottom of the air outlet flow channel 17, and the other end is fixedly connected to the end of the shielding pipe 13 away from the thermally expandable ring 14. A limiting ring 16 that cooperates with and abuts against the thermally expandable ring 14 is arranged at one end of the shielding pipe 13. A number of through holes 12 are arranged on the shielding pipe 13.

[0059] In the above solution, the normal state of the shielding component is as Figure 4 shown. The through holes and the air outlet holes are arranged in an alternating manner, and the shielding pipe blocks the air outlet holes. After hot air is introduced into the air outlet flow channel, the thermally expandable ring undergoes an axial deformation, driving the shielding pipe to move, so that the through holes on the shielding pipe and the air outlet holes are on the same axis, and the hot air in the air outlet flow channel can be ejected from the air outlet holes. When the hot air generator stops working after the drying is completed, the temperature in the air outlet flow channel decreases, the thermally expandable ring returns to its initial position, and the shielding pipe returns to its original position under the action of the second spring to block the air outlet holes.

[0060] The above is only an illustration of the best embodiment of the present invention, but it should not be construed as a limitation of the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to vary. All changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

Claims

1. A method for processing modified starch for papermaking, characterized in that: The processing method comprises the following steps: S1. Soaking and washing the cassava; S2, the cleaned cassava is placed in a drying device for surface drying; S3, crushing the cassava to obtain cassava slurry, and separating the cassava slurry into starch slurry by a centrifuge; S4, adding acetic anhydride to the starch slurry, reacting at 20-35° C. and pH 8.2-9.8 for 40-90 minutes; S5, adding protective agent, reacting at 32-38°C, pH 7.1-11.9 for 15-50 minutes; S6, add 3-chloro-2-hydroxypropyl-trimethylammonium chloride, and react at 40-45° C. and pH 7.5-9.5 for 100-250 minutes; S7, using a concentrator to concentrate the slurry after the mixed reaction, and then dehydrating the concentrated slurry; S6, sending the dehydrated starch into a drying device for drying; S7, sending the dried modified starch into the silo of the loader for bagging and packaging.

2. The method for processing modified starch for papermaking according to claim 1, characterized in that: The amount of acetic anhydride added in S4 is 4-18% of the mass of starch in the starch slurry.

3. The method for processing modified starch for papermaking according to claim 1, characterized in that: The protective agent in S5 is sodium chloride.

4. The method for processing modified starch for papermaking according to claim 3, characterized in that: The amount of sodium chloride added is 8-25% of the mass of starch in the starch slurry.

5. The method for processing modified starch for papermaking according to claim 1, characterized in that: The amount of 3-chloro-2-hydroxypropyl-trimethylammonium chloride added in S6 is 4-15% of the mass of starch in the starch slurry.

6. The method for processing modified starch for papermaking according to claim 1, characterized in that: The drying device in S6 includes a drying box, a hot air drying component and a screen component. The drying box is provided with a feed port. The hot air drying component is installed in the drying box for drying the modified starch in the drying box. The screen component includes a screening net and a spring 1. A mounting rod is provided inside the drying box. One end of the spring 2 is fixedly connected to the mounting rod, and the other end is fixedly connected to the lower end surface of the screening net.

7. The method for processing modified starch for papermaking according to claim 6, characterized in that: The hot air drying component includes a hot air generator, a connecting pipe and a rotating air outlet mechanism. The hot air generator is used to generate hot air. One end of the connecting pipe is connected to the hot air generator, and the other end is rotatably connected to the rotating air outlet mechanism installed on the drying box. The hot air generated by the hot air generator enters the rotating air outlet mechanism through the connecting pipe. The rotating air outlet mechanism rotates in the drying box and discharges air to dry the modified starch in the drying box.

8. The method for processing modified starch for papermaking according to claim 7, characterized in that: The rotating air outlet mechanism includes a motor, a rotating shaft and a plurality of fixed rods, the motor is installed on one side of the drying box, one end of the rotating shaft is transmission-connected to the motor, and the other end extends into the interior of the drying box and is rotationally connected to a connecting pipe, an air inlet channel is provided on the rotating shaft, a plurality of fixed rods are installed on the rotating shaft, an air outlet channel connected to the air inlet channel is axially provided inside the fixed rod, and a plurality of air outlet holes connected to the air outlet channel are provided on the fixed rod.

9. The method for processing modified starch for papermaking according to claim 8, characterized in that: A shielding component is arranged in the air outlet flow channel, and the shielding component automatically opens to open the air outlet hole when hot air enters the air outlet flow channel, and automatically closes when the hot air disappears in the air outlet flow channel.

10. The method for processing modified starch for papermaking according to claim 9, characterized in that: The shielding assembly includes a thermostatic ring, a shielding tube and a second spring. One end of the air outlet channel is provided with a mounting groove for mounting the thermostatic ring. The shielding tube can be movably mounted in the air outlet channel. One end of the second spring is fixedly connected to the bottom of the air outlet channel, and the other end is fixedly connected to an end of the shielding tube away from the thermostatic ring. One end of the shielding tube is provided with a limiting ring that cooperates with the thermostatic ring and abuts against the thermostatic ring. The shielding tube is provided with a plurality of through holes.

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