Citric acid production

ZAVKOM-ENGINEERING designs and supplies equipment for citric acid producing companies.

Raw materials for citric acid production:

  • Wheat
  • Corn
  • Wheat / corn starch

Citric acid is a common organic acid that is used in the food industry as an oxidizer, acidity regulator (pH), and preservative in combination with other substances. It is also used in medicine and chemical-pharmaceutical, chemical, textile, leather, metallurgical, and nuclear industries.

To date, there is no operating citric acid production plant in Russia. Thus, citric acid is fully imported, mainly from China.

The implementation of such projects will allow to meet the growing demands of various branches of the Russian industry in citric acid, to make important steps in overcoming dependence on imported supplies of citric acid, so that consumers will receive a range of high-quality products.

Citric acid biosynthesis

Biosynthesis is carried out in special fermenters equipped with devices for medium aeration, excess heat removal, mixing, as well as a set of necessary control and measuring equipment. Culture medium saturation with oxygen is provided by a continuous air supply to the fermenter and a specially designed mixing device, which is used to achieve the maximum degree of oxygen dissolution in the medium. After the fermentation process is completed, the culture liquid is sterilized and then enters the filtration section. The culture liquid is released from almost all suspended undissolved substances (mycelium of the fungus, colloids) during filtration, after which the pure filtrate enters citric acid extraction section. Filtration is carried out in 2 stages, which ensures, on the one hand, the maximum citric acid extraction from the culture liquid, on the other–the maximum concentration of dry substances in the cake. Solid sediment (cake) is dried to 10% humidity after filtration and enters the packing area.

The pure filtrate of the culture liquid enters the chemical shop (section). Here the filtrate is treated with lime solution (or calcium carbonate suspension) in special reactors. An insoluble precipitate of citric acid calcium salt–calcium citrate — is formed as a result of the chemical reaction. Then calcium citrate is filtered out on the belt vacuum filters and enters the acidolysis stage. Calcium citrate is treated with concentrated sulfuric acid in acidolysis reactors. An insoluble precipitate of calcium sulfate (gypsum) falls out of the solution as a result of a chemical reaction and pure citric acid passes into the solution.