Method of continuous evaporation crystallization and production method of anhydrous citric acid crystal

An anhydrous citric acid, evaporative crystallization technology, applied in evaporation, separation method, solution crystallization and other directions, can solve the problems such as small particle size of anhydrous citric acid crystal products, easy agglomeration of anhydrous citric acid crystal products, and inability to remove moisture. , to achieve the effect of reducing aggregation, increasing particle size and improving anti-caking performance.

Inactive Publication Date: 2012-07-11
COFCO BIOTECHNOLOGY CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] There is following shortcoming in the production method of above-mentioned anhydrous citric acid crystal: add citric acid solution and feed from crystallizer middle part or bottom, due to intense evaporative crystallization, make the liquid level of the citric acid solution in the crystallizer produce splashed droplet, The droplet collides with the inner wall of the crystallizer to generate crystal scale (fine anhydrous citric acid crystal grains). As the evaporation and crystallization process proceeds, the crystal scale adheres to each other and covers a small amount of water, which increases the quality of the crystal scale. However, it falls off from the inner wall of the cr

Method used

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  • Method of continuous evaporation crystallization and production method of anhydrous citric acid crystal
  • Method of continuous evaporation crystallization and production method of anhydrous citric acid crystal
  • Method of continuous evaporation crystallization and production method of anhydrous citric acid crystal

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Experimental program
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Effect test

Embodiment 1

[0048] use figure 1 The crystallizer shown, wherein the cavity 7 volume is 18m 3 , inner diameter D=2.2m, height H=6m, crystal discharge port 8 is positioned at the bottom of cavity 7, and viewing mirror 6 is positioned at the top of crystal discharge port 8, is 3.5m apart from the 8 heights of crystal discharge port; The port 5 is located above the viewing mirror 6, and the height from the crystal discharge port 8 is 4.2m; the wire mesh demister 3 is located above the feed port 5, and the height from the crystal discharge port 8 is 4.9m. The annular pipe 4 made of stainless steel 316L communicates with the feed port 5, and is horizontally arranged in the cavity 7 along the inner surface of the crystallizer. The inner diameter of the annular pipe 4 is d=50mm. A hole-like structure 10 is provided every 65 mm in the axial direction. The hole-like structure 10 is a round hole with a diameter of 5 mm. The opening direction of the hole-like structure 10 faces the inner surface of ...

Embodiment 2

[0068] Using the crystallizer of Example 1, the difference is that the opening direction of the hole structure 10 faces the inner surface of the cavity 7, and the angle between the axis a of the hole perpendicular to the hole plane and the axis b of the cavity is 30°. Pass the test, when the distance is 3-9m from the ring pipe 4 3 When water is added at a flow rate of / h, it can be visually observed that the water flows down in the form of a liquid film along the inner wall of the cavity 7 .

[0069] The citric acid content is 60% by weight, the citric acid purity is greater than 99% by weight, and the density is 1264kg / m 3 The citric acid solution is pumped into the effective volume of 15m 3 The annular pipe 4 above the crystallizer, the solution is 4.6m 3 The flow rate of / h is continuously rinsed from the hole-like structure 10 in the annular pipe 4 along the inner wall of the cavity 7 and enters the crystallizer for evaporation and crystallization. It is 60 ℃ that the t...

Embodiment 3

[0073] The same crystallizer as in Example 1 was used.

[0074] The citric acid content is 57% by weight, the citric acid purity is greater than 99% by weight, and the density is 1248kg / m 3 The citric acid solution is pumped into the effective volume of 15m 3 The annular pipe 4 above the crystallizer, the solution is 5.388m 3 The flow rate of / h is continuously rinsed from the hole-like structure 10 in the annular pipe 4 along the inner wall of the cavity 7 and enters the crystallizer for evaporation and crystallization. It is 60 ℃ that the temperature is set in the crystallizer, and vacuum is-90kPa, when the citric acid content in the citric acid solution is 76% by weight (the citric acid solution that has passed into the citric acid content of this moment is 57% by weight is 21.94m 3 ), add 80-200 order anhydrous citric acid seed crystal 10kg in this citric acid solution (corresponding to degree of supersaturation 1.1), maintain 1 hour then, when solid content accounts for...

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Abstract

The invention provides a method of continuous evaporation crystallization and a production method of anhydrous citric acid crystal. A crystallizer used in the method comprises a cavity; the method comprises pouring materials to be crystallized into the cavity continuously; carrying out evaporation crystallization to the materials to be crystallized under an evaporation crystallization condition; and discharging mixture with crystal during the evaporation crystallization process; the method is characterized in that the materials to be crystallized are added into the cavity along the inner wall of the cavity from the position higher than the liquid level in mode of liquid membrane partially or completely. With the method of the continuous evaporation crystallization, provided by the invention, the moisture content in the crystal is reduced and the anti-caking capacity of the crystal is improved. According to the method provided by the invention, the anhydrous citric acid seed crystal is added and lasted for a certain period during the production of the anhydrous citric acid crystal, the time of a crystallization system reaching the balance state is shortened greatly, and the particle diameter of the anhydrous citric acid crystal before the crystallization system reaches the balance state is enlarged.

Description

technical field [0001] The present invention relates to a method for continuous evaporative crystallization and a method for producing anhydrous citric acid crystals using the continuous evaporative crystallization method. Background technique [0002] Anhydrous citric acid is mainly used in the food and beverage industry as a sour agent, flavoring agent, preservative, and preservative. It is also used as antioxidant, plasticizer and detergent in chemical industry, cosmetic industry and washing industry. At present, the continuous production method of anhydrous citric acid in the industry includes: first, the citric acid fermentation liquid is separated from the solid and liquid to obtain the citric acid clear liquid, and the citric acid clear liquid is purified by the calcium salt method or the hydrogen calcium method, the acid hydrolysis method, and decolorization. The solution is heated and concentrated, the temperature of the citric acid concentrate is controlled to be ...

Claims

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Application Information

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IPC IPC(8): B01D9/02B01D1/00C07C59/265C07C51/43
Inventor 周勇熊结青许贵珍周维英陈影
Owner COFCO BIOTECHNOLOGY CO LTD
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