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A kind of method for preparing anhydrous citric acid crystal

A technology for citric acid and crystals, applied in the field of preparing anhydrous citric acid crystals, can solve the problems of low product quality, low impurity content, and low moisture content of anhydrous citric acid crystals, so as to improve the first pass rate, low impurity content, Uniform particle size effect

Active Publication Date: 2015-10-21
COFCO BIOTECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the defects of low quality anhydrous citric acid crystals obtained by existing methods, and to provide a crystal that can efficiently obtain uniform particle size, low impurity content, high bulk density and low moisture content that is not easy to agglomerate The method for the preparation of product anhydrous citric acid crystals

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0011] The method for preparing anhydrous citric acid crystals provided by the present invention comprises concentrating and crystallizing a citric acid feed liquid, wherein, when the crystal content in the feed liquid reaches 20-40% by weight (preferably 25-35% by weight), the concentrated The crystal slurry obtained by crystallization is classified, and the classification conditions are controlled so that the crystals with a particle size of less than 600 μm are separated from the crystal slurry, and part or all of the crystal slurry obtained by classification and containing crystals with a particle size of less than 600 μm is returned to the citric acid material. The liquids were mixed together for concentrated crystallization.

[0012] According to the present invention, the conditions of the concentrated crystallization can be the conditions conventionally used in the field, and preferably, the conditions of the concentrated crystallization are such that the particle size ...

Embodiment 1

[0022] The citric acid feed liquid with a citric acid content of 60% by weight is continuously injected into an effective volume of 20m 3 In the crystallizer, concentrated crystallization is carried out at 60 ° C, when the crystal content in the feed liquid reaches 35% by weight, the feeding speed of the citric acid feed liquid and the discharging speed of the crystal slurry obtained by concentrated crystallization are controlled to make the feed liquid in the feed liquid. The content of the crystals is kept constant, and the crystal slurry obtained by the concentrated crystallization (the particle size of the contained crystals does not exceed 850 μm) is passed into the hydrocyclone for classification, and the feeding pressure is controlled to be 0.4MPa, and the feeding speed is 3m 3 / h, so that crystals with a particle size of less than 600 μm are separated from the crystal slurry, and the crystallized slurry containing crystals with a particle size of less than 600 μm obtain...

Embodiment 2

[0025] The citric acid feed liquid with a citric acid content of 55% by weight is continuously injected into an effective volume of 20 m 3 In the crystallizer, concentrated crystallization is carried out at 60 ° C, and when the crystal content in the feed liquid reaches 30% by weight, the feeding speed of the citric acid feed liquid and the discharging speed of the crystal slurry obtained by the concentrated crystallization are controlled to make the feed liquid in the feed liquid. The content of the crystals is kept constant, and the crystal slurry obtained by concentrated crystallization (the particle size of the contained crystals is not more than 850 μm) is passed into the hydrocyclone for classification, and the feeding pressure is controlled to be 0.2MPa, and the feeding speed is 10m 3 / h, so that crystals with a particle size of less than 600 μm are separated from the crystal slurry, and the crystallized slurry containing crystals with a particle size of less than 600 μm...

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PUM

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Abstract

The invention discloses a method for preparing an anhydrous citric acid crystal. The comprises the following steps: concentrating and crystalizing citric acid liquor, grading the concentrated and crystallized crystal slurry when the content of crystals in the liquor is up to 20-40wt%, controlling the grading conditions so as to separate crystals, with the particle size of less than 600mu m, from the crystal slurry, and returning partially or entirely graded crystal slurry, containing crystals with the particle size of less than 600mu m, and mixing crystal slurry together with citric acid liquor for concentration and crystallization. Through the technical scheme, the anhydrous citric acid crystal which is uniform in particle size, low in the content of impurities, high in piling density, low in moisture content and difficult to cake can be obtained. Furthermore, the method can improve the first-pass yield of citric acid products, the obtained crystal product is not required for a sieving step, therefore, the production efficiency of the anhydrous citric acid crystals can be improved.

Description

technical field [0001] The present invention relates to a method for preparing anhydrous citric acid crystals. Background technique [0002] At present, the continuous production method of anhydrous citric acid crystal products in the industry includes: firstly separating the citric acid fermentation liquid through solid-liquid separation to obtain a citric acid clear liquid, using the hydrogen calcium method or the calcium salt method to precipitate the citric acid clear liquid, and acidolysis the precipitate. , the acidolysis product is decolorized, the decolorized solution is heated and concentrated, and the concentrated citric acid feed liquid obtained is continuously injected into the crystallizer, when the crystal content accounts for 46-60% by weight of the total weight of the mixture of citric acid solution and solid , start to continuously and quantitatively discharge the crystal slurry containing anhydrous citric acid crystals, keep the system running continuously,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C59/265C07C51/43
CPCC07C51/43C07C59/265
Inventor 罗虎熊结青许贵珍高志林陶俊
Owner COFCO BIOTECHNOLOGY CO LTD