A reaction kettle device and reaction process for producing sodium percarbonate

Abstract

The present invention belongs to the technical field of sodium percarbonate production process, and specifically relates to a reactor device and reaction process for sodium percarbonate production. The present invention reduces the foam temperature in advance by adding polyacrylate before the reaction, so that the foam and the reaction liquid can be heat exchanged in time, and the heat energy utilization rate is improved, thereby solving the problem of slow reaction rate in the existing sodium percarbonate production process due to the failure to timely remove heat. The reactor device for sodium percarbonate production includes a reactor body, a foam storage tank and a defoaming mechanism. The present invention reduces the foam temperature in advance by adding polyacrylate before the reaction, so that the foam and the reaction liquid can be heat exchanged in time, and the heat energy utilization rate is improved; at the same time, the foam with higher temperature is removed in time through the first defoamer and the foam absorber, and the reaction heat is taken away, creating an environment conducive to the reaction temperature, which is conducive to the crystallization of the material, improving the product quality, and reducing energy consumption, thereby increasing the production capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of sodium percarbonate production technology, and specifically relates to a reaction kettle device and a reaction process for sodium percarbonate production. Background Art

[0002] Sodium percarbonate, also known as solid hydrogen peroxide, has the dual properties of sodium carbonate and hydrogen peroxide. It is a representative of high-efficiency oxygen-based bleaching agents. With its excellent bleaching activity and bactericidal properties, it has been widely used in washing, printing and dyeing, textiles, papermaking, medicine and health, household and personal care product formulations and other fields.

[0003] At present, there are two major production processes for sodium percarbonate. One is dry production: hydrogen peroxide is continuously sprayed on anhydrous sodium carbonate on the fluid at high temperature and then dried to obtain the finished product. This method has a simple process and a short production process, but the equipment is complex, the technical conditions are harsh, and the energy consumption is high. The other is wet production: a certain concentration of hydrogen peroxide is reacted with sodium carbonate at a certain humidity, and the product is crystallized, separated, and dried. This method has a mature process and a high product yield. However, this process has a long process flow, a long reaction time, and a complex operation and is difficult to control. In addition, when the reactor currently used starts to react, because the liquid level of the reaction liquid is low, the heat exchange area of ​​both the built-in coil and the jacket heat exchanger is small, resulting in a slow heat exchange rate, and the reaction heat cannot be removed in time, resulting in a slow reaction rate.

[0004] To this end, the present application aims at the technical problems existing in the prior art, improves the equipment structure of the wet production of sodium percarbonate, and adjusts the reaction process conditions, so as to avoid the phenomenon that the heat exchange rate is slow due to the small heat exchange area, resulting in incomplete reaction or the inability to react smoothly. Summary of the invention

[0005] In view of the defects existing in the prior art, the present invention aims to provide a reactor device for sodium percarbonate production, which reduces the foam temperature in advance by adding polyacrylate before the reaction, so that the foam and the reaction liquid can exchange heat in time, improve the utilization rate of thermal energy, and thus solve the problem of slow reaction rate caused by the failure to timely extract heat in the existing sodium percarbonate production process.

[0006] The invention also provides a reaction process for the sodium percarbonate production reactor.

[0007] Based on the above purpose, the present invention adopts the following technical solutions:

[0008] A reaction kettle device for sodium percarbonate production, comprising a kettle body, a foam storage tank and a defoaming mechanism;

[0009] A kettle cover is arranged at the top of the kettle body, a stirring anchor is arranged inside the kettle body, and the top shaft end of the stirring anchor extends upward and passes through the kettle cover;

[0010] A feed pipe is provided on the top of the kettle cover, and a discharge pipe is provided at the bottom of the kettle body;

[0011] An overflow port is provided on the side wall of the kettle body, and the overflow port is connected to the foam storage tank through a first pipe;

[0012] The defoaming mechanism comprises a first defoamer and a foam absorber arranged in the kettle body;

[0013] The top end of the foam absorber is connected to the inlet end of the first defoamer;

[0014] A second pipe is provided at the outlet end of the first defoamer. The second pipe passes through the kettle body and is connected to the foam storage tank.

[0015] Furthermore, a stirring motor is arranged above the kettle body, and the shaft end of the stirring anchor is connected to the output shaft of the stirring motor.

[0016] Furthermore, a material detection tube and a manhole are provided on the top of the kettle cover. By providing the manhole, when the kettle body needs to be repaired, the staff can enter the kettle body to repair it.

[0017] Furthermore, the defoaming mechanism includes a second defoamer arranged outside the kettle body.

[0018] Furthermore, the first defoamer is connected to the inner wall of the kettle body through a bracket.

[0019] Furthermore, the foam absorber is a structure with an open bottom.

[0020] Further, the foam absorber is located above the overflow port.

[0021] Furthermore, the outlet end of the foam storage tank is connected to the second defoamer through a third pipe, and a pump is provided on the third pipe, through which the foam in the foam storage tank is pumped into the second defoamer for defoaming treatment.

[0022] Furthermore, the outlet end of the second defoamer is also connected to the feed pipe of the kettle body through a fourth pipe, so that the foam liquid that has undergone defoaming treatment is transported to the kettle body for recycling.

[0023] Furthermore, the models of the first defoamer and the second defoamer are TIAN-A-5-0.75; the model of the foam absorber is ADLM50.

[0024] The process for producing sodium percarbonate by reaction using the above reactor device comprises the following steps:

[0025] (1) Formation of a foamy reaction environment: Add mother liquor into the reactor through a feed pipe. The mother liquor includes sodium carbonate, sodium chloride, sodium silicate, magnesium sulfate and water. Then add polyacrylate into the reactor through a feed pipe and react. Stir continuously during the reaction. The polyacrylate forms foam. The reaction temperature is 25-35°C and the reaction time is 20-30 minutes. The polyacrylate forms foam and fills the entire reactor cavity.

[0026] (2) Preparation of sodium percarbonate: sodium carbonate slurry and hydrogen peroxide are added to the reactor through a feed pipe; sodium carbonate slurry, hydrogen peroxide, polyacrylate and mother liquor are mixed to form a reaction liquid, and sodium percarbonate is prepared by reaction; as the reaction liquid increases and the amount of foam formed by the polyacrylate increases, the volume of the reaction liquid continues to increase, and the liquid level gradually moves upward, at which time the excess polyacrylate foam will overflow through the overflow port and flow into the foam storage tank through the first pipeline, and a one-way valve may also be provided on the first pipeline to prevent the backflow of the liquid; the foam that fails to overflow through the overflow port in time is absorbed by the foam absorber and discharged into the foam storage tank through the second pipeline; if there is too much foam and it cannot be removed in time, the first defoamer equipment is started to perform defoaming treatment;

[0027] The foam in the foam storage tank can be reused. The sodium percarbonate production reactor device also includes a second defoamer. The outlet end of the foam storage tank is connected to the second defoamer through a third pipe. The outlet end of the third pipe connected to the foam storage tank is provided with a pump. The foam in the foam storage tank is pumped into the second defoamer for defoaming treatment through the pump.

[0028] The outlet end of the second defoamer is also connected to the feed pipe of the kettle body through a fourth pipe, so that the foam liquid after defoaming treatment is transported to the kettle body for recycling;

[0029] (3) After the reaction in step (2), the material is discharged through a discharge pipe, and then the material undergoes a crystallization process, a filtration process, a solid-liquid separation process, and a drying process to obtain a dry sodium percarbonate product.

[0030] Specifically, the volume of the mother liquor in step (1) is 1 / 10-1 / 5 of the volume of the reactor.

[0031] Specifically, the mother liquor components in step (1) include sodium carbonate, sodium chloride, sodium silicate, magnesium sulfate, and water, wherein the mass percentages of the individual components are: sodium carbonate 5-8%, sodium chloride 15-18%, sodium silicate 0.5-1%, magnesium sulfate 0.5-1%, and the balance is water.

[0032] Specifically, the polyacrylate added in step (1) is 0.1-0.2% of the mass of the mother solution, and the polyacrylate is sodium polyacrylate or potassium polyacrylate.

[0033] Specifically, the mass fraction of hydrogen peroxide in step (2) is 35%.

[0034] Specifically, when sodium carbonate slurry and hydrogen peroxide are mixed in step (2), sodium carbonate and H 2 O 2 The molar ratio is 1:1.2-1.4.

[0035] Specifically, the reaction steps of the crystallization, filtration, solid-liquid separation and drying process in step (3) are as follows:

[0036] a. Sodium carbonate and hydrogen peroxide are reacted in the molar ratio in step (2) and crystallized at normal pressure and 25-35° C., and filtered to precipitate crystals of 40-100 mesh;

[0037] b. Then centrifuge it at a pressure of 1.8-2.0MPa and a temperature of 90-100℃ for 5-10min, and dry it for 1-2 hours after centrifugation.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] Different from the traditional wet process, the present invention reduces the foam temperature in advance by adding polyacrylate before the reaction, so that the foam can exchange heat with the reaction liquid in time, thereby improving the utilization rate of thermal energy; at the same time, the foam with higher temperature is removed in time through the first defoamer and the foam absorber, taking away the reaction heat, creating an environment conducive to the reaction temperature, facilitating material crystallization, improving product quality, reducing energy consumption, greatly shortening the reaction time, and thus improving production capacity.

[0040] After the polyacrylate is used to form foam under stirring during the reaction process, the excess foam can be stored in a foam storage tank and reused, thereby improving the cycle efficiency of the process, saving energy and protecting the environment, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the structure of a reactor device for producing sodium percarbonate according to Example 1 of the present invention. DETAILED DESCRIPTION

[0042] In order to make the technical purpose, technical scheme and beneficial effects of the present invention clearer, the technical scheme of the present invention is further described below in conjunction with specific embodiments. However, the embodiments are intended to explain the present invention and cannot be understood as limiting the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in the field or the product manual shall be followed.

[0043] Example 1

[0044] like Figure 1As shown, a reaction kettle device for sodium percarbonate production includes a kettle body 1, a foam storage tank 10 and a defoaming mechanism;

[0045] A stirring motor 3 is arranged above the kettle body 1, a kettle cover 2 is arranged at the top of the kettle body 1, a stirring anchor 4 is arranged at the lower part of the kettle body 1, the top shaft end of the stirring anchor 4 extends upward and passes through the kettle cover 2, and the shaft end of the stirring anchor 4 is connected to the output shaft of the stirring motor 3;

[0046] A feed pipe 5 and a material detection pipe 7 are provided on the left side of the top of the kettle cover 2, a manhole 6 is provided on the right side of the top of the kettle cover 2, and a discharge pipe 8 is provided at the bottom of the kettle body 1. By providing the manhole 6, when the kettle body 1 needs to be repaired, the staff can enter the kettle body 1 to repair the kettle body 1;

[0047] The side wall of the kettle body 1 is provided with an overflow port 9, and the overflow port 9 is connected to the foam storage tank 10 through a first pipe;

[0048] The defoaming mechanism includes a first defoamer 11 and a foam absorber 12 arranged in the kettle body 1, and a second defoamer 13 arranged outside the kettle body 1. Specifically, the first defoamer 11 is connected to the inner wall of the kettle body 1 through a bracket;

[0049] The foam absorber 12 is a structure with an open bottom end, and the top end of the foam absorber 12 is connected to the inlet end of the first defoamer 11;

[0050] The foam absorber 12 is located above the overflow port 9;

[0051] A second pipe is provided at the outlet end of the first defoamer 11 . The second pipe passes through the kettle body 1 and is connected to the foam storage tank 10 .

[0052] The outlet end of the foam storage tank 10 is connected to the second defoamer 13 through a third pipe, and a pump 14 is provided on the third pipe. The foam in the foam storage tank 10 is pumped into the second defoamer 13 through the pump 14 for defoaming treatment;

[0053] The outlet end of the second defoamer 13 is also connected to the feed pipe 5 of the kettle body 1 through the fourth pipe 15, so as to transport the defoamed foam liquid to the kettle body 1 for recycling.

[0054] The models of the first defoamer 11 and the second defoamer 13 are TIAN-A-5-0.75; the model of the foam absorber 12 is ADLM50.

[0055] Example 2

[0056] The process of producing sodium percarbonate by using the above reactor device for reaction is as follows:

[0057] (1) Formation of a high foam reaction environment: First, a mother liquor having a volume of 1 / 10 of the volume of the reactor is added to the reactor through the feed pipe 5, wherein the mother liquor comprises sodium carbonate, sodium chloride, sodium silicate, magnesium sulfate and water, wherein the mass percentages of the respective components are: 5-8% sodium carbonate, 15-18% sodium chloride, 0.5-1% sodium silicate, 0.5-1% magnesium sulfate, and the remainder is water. Then, a polyacrylic acid salt (sodium polyacrylate) having a mass of 0.1% of the mass of the mother liquor is added to the reactor through the feed pipe 5, and then the stirring motor 3 is started, and the stirring anchor 4 is driven to rotate for stirring. The reaction temperature during stirring is controlled at 25-35° C. After stirring for 20-30 minutes, the polyacrylic acid salt forms foam that fills the entire inner cavity of the reactor body 1.

[0058] (2) Preparation of sodium percarbonate by stirring reaction: sodium carbonate slurry (sodium carbonate slurry is a supersaturated solution of sodium carbonate, which is a suspension) and hydrogen peroxide (liquid with a mass fraction of 35%) are added to the reactor through the feed pipe 5. In the mixture of sodium carbonate slurry and hydrogen peroxide, sodium carbonate and H 2 O 2 The molar ratio is 1:1.2-1.4; sodium carbonate slurry, hydrogen peroxide, polyacrylate and mother liquor are mixed to form a reaction liquid, and sodium percarbonate is prepared by reaction; as the reaction liquid increases and the amount of foam formed by the polyacrylate increases, the volume of the reaction liquid continues to increase, and the liquid level gradually moves upward, at which time the excess polyacrylate foam will overflow through the overflow port 9 and flow into the foam storage tank 10 through the first pipeline, and a one-way valve may also be provided on the first pipeline to prevent the reflux of the liquid; the foam that fails to overflow through the overflow port 9 in time is absorbed by the foam absorber 12 and discharged into the foam storage tank 10 through the second pipeline; if there is too much foam and it cannot be removed in time, the first defoamer 11 equipment is started to perform defoaming treatment;

[0059] The foam in the foam storage tank 10 can be reused. The sodium percarbonate production reactor device also includes a second defoamer 13. The outlet end of the foam storage tank 10 is connected to the second defoamer 13 through a third pipe. The outlet end of the third pipe connected to the foam storage tank 10 is provided with a pump 14. The foam in the foam storage tank 10 is pumped into the second defoamer 13 for defoaming treatment through the pump 14.

[0060] The outlet end of the second defoamer 13 is also connected to the feed pipe 5 of the kettle body 1 through the fourth pipe 15, so as to transport the defoamed foam liquid to the kettle body 1 for recycling;

[0061] (3) After the reaction in step (2), the material is discharged through the discharge pipe 8, and the material undergoes a crystallization process, a filtration process, a solid-liquid separation process, and a drying process to obtain a dry sodium percarbonate product.

[0062] The specific reaction steps are as follows:

[0063] a. Sodium carbonate and hydrogen peroxide are reacted in the molar ratio in step (2) and crystallized at normal pressure and 25-35° C., and filtered to precipitate crystals of 40-100 mesh;

[0064] b. Then centrifuge at a pressure of 2.0 MPa and a temperature of 90-100°C for 5 minutes. During the centrifugation process, the thickness of the material layer is controlled to be about 50 cm. After centrifugation, dry for 2 hours, and then further classify the obtained crystals through a vibrating screen and store them in a warehouse. The separation rate of centrifugation is about 93%.

[0065] Sodium tripolyphosphate and sodium citrate can be added as stabilizers to the hydrogen peroxide used in the present invention to increase the service life of the hydrogen peroxide. In the preparation process of the sodium carbonate slurry, a complexing agent (sodium silicate and magnesium sulfate) can also be added to precipitate impurities and sodium chloride in the sodium carbonate raw material (which helps crystal precipitation and forms crystal nuclei).

[0066] During the whole reaction process, due to the addition of polyacrylate, the reaction temperature is kept stable at about 25° C., without drastic temperature fluctuations, and the product is stable and has a high yield. During the reaction process, a certain amount of material can be extracted from the material detection tube 7 for index detection.

[0067] Reaction energy consumption and reaction yield:

[0068] 1. The sodium percarbonate production reactor device of the present invention can reduce energy consumption:

[0069] In summer, the energy consumption is reduced to 84.6% of the original value, calculated based on the average outdoor temperature of 35°C and the reaction temperature of 25°C. In winter, the energy consumption is reduced to 76.9% of the original value, calculated based on the average outdoor temperature of 5°C and the reaction temperature of 25°C.

[0070] 2. The yield of sodium percarbonate prepared by the sodium percarbonate production reactor device and process of the present invention is increased from 88.7% to 89.2%, and the proportion of sodium percarbonate crystals with a size of 0.25-1 mm is increased from 90.1% to 91.3%; the bulk density of the product is increased from 0.85 g / cm 3 , increased to 0.91g / cm 3 , with good production efficiency.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate but not to limit the technical solutions of the present invention. Any equivalent substitutions of the present invention and any modifications or partial substitutions that do not depart from the spirit and scope of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A reaction kettle device for sodium percarbonate production, characterized in that: It includes a kettle body, a foam storage tank and a defoaming mechanism; A kettle cover is arranged at the top of the kettle body, a stirring anchor is arranged inside the kettle body, and the top shaft end of the stirring anchor extends upward and passes through the kettle cover; A feed pipe is provided on the top of the kettle cover, and a discharge pipe is provided at the bottom of the kettle body; An overflow port is provided on the side wall of the kettle body, and the overflow port is connected to the foam storage tank through a first pipe; The defoaming mechanism comprises a first defoamer and a foam absorber arranged in the kettle body; The top end of the foam absorber is connected to the inlet end of the first defoamer; A second pipe is provided at the outlet end of the first defoamer. The second pipe passes through the kettle body and is connected to the foam storage tank.

2. The sodium percarbonate production reactor device according to claim 1, characterized in that A stirring motor is arranged above the kettle body, and the shaft end of the stirring anchor is connected to the output shaft of the stirring motor.

3. Sodium percarbonate production reactor device according to claim 1, is characterized in that, The defoaming mechanism comprises a second defoamer arranged outside the kettle body; the foam absorber is a structure with an open bottom; and the foam absorber is located above the overflow port.

4. The sodium percarbonate production reactor device according to claim 1, characterized in that The outlet end of the foam storage tank is communicated with the second defoamer through a third pipeline.

5. The sodium percarbonate production reactor device according to claim 1, characterized in that, The outlet end of the second defoamer is also connected to the feed pipe of the kettle body through a fourth pipeline.

6. The reaction process of the sodium percarbonate production reactor device using any one of claims 1 to 5 is characterized in that: The steps include: (1) Formation of a foaming reaction environment: adding a mother liquor into the reactor through a feed pipe, wherein the mother liquor comprises sodium carbonate, sodium chloride, sodium silicate, magnesium sulfate and water, and then adding polyacrylate into the reactor through a feed pipe, and then reacting. During the reaction, stirring is continued, and the polyacrylate forms foam. The reaction temperature is 25-35°C, and the reaction time is 20-30 min. (2) Preparation of sodium percarbonate: sodium carbonate slurry and hydrogen peroxide are added to a reaction kettle through a feed pipe; the sodium carbonate slurry, hydrogen peroxide, polyacrylate and mother liquor are mixed to form a reaction liquid, and sodium percarbonate is prepared by reaction; (3) After the reaction in step (2), the material is discharged through a discharge pipe, and then the material undergoes a crystallization process, a filtration process, a solid-liquid separation process, and a drying process to obtain a dry sodium percarbonate product.

7. The reaction process according to claim 6, characterized in that: The volume of the mother liquor in step (1) is 1 / 10-1 / 5 of the volume of the reaction kettle; the polyacrylate added in step (1) is 0.1-0.2% of the mass of the mother liquor, and the polyacrylate is sodium polyacrylate or potassium polyacrylate.

8. The reaction process according to claim 6, characterized in that: The mother liquor components in step (1) include sodium carbonate, sodium chloride, sodium silicate, magnesium sulfate and water, wherein the mass percentages of the respective components are: sodium carbonate 5-8%, sodium chloride 15-18%, sodium silicate 0.5-1%, magnesium sulfate 0.5-1%, and the balance is water.

9. The reaction process according to claim 6, characterized in that: The mass fraction of hydrogen peroxide in step (2) is 35% of liquid; when the sodium carbonate slurry and hydrogen peroxide are mixed in step (2), the molar ratio of sodium carbonate to H2O2 is 1:1.2-1.

4.

10. The reaction process according to claim 6, characterized in that: The reaction steps of the crystallization, filtration, solid-liquid separation and drying process in step (3) are as follows: a. Sodium carbonate and hydrogen peroxide are reacted in the molar ratio in step (2) and crystallized at normal pressure and 25-35° C., and filtered to precipitate crystals of 40-100 mesh; b. Then centrifuge it at a pressure of 1.8-2.0MPa and a temperature of 90-100℃ for 5-10min, and dry it for 1-2 hours after centrifugation.

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