The application of the evaporation system in the deep processing of citric acid

Process Introduction:

 

First, the raw material corn is sorted and then ground. The ground corn is sieved through a 60-mesh screen to obtain qualified corn flour. The corn flour is transported to the mixing tank through the material conveyor. Add 65°C water in a ratio of 1:4.5 by mass to the mixing tank. Use the alkaline salt Na2CO3 solution to adjust the pH of the slurry within the range of 5.0 to 7.0, and add 0.1% calcium chloride as a protective agent and activator for the amylase. The slurry is injected into the liquefaction tank. Liquefy for 30 minutes, raise the temperature to kill the high-temperature-resistant amylase. Filter the liquefied liquid to remove corn residue to obtain the liquefied clear liquid. Cool down. Then enter the fermentation tank, add 0.9% urea, 0.1% KH3PO4, 0.25% MgSO4 and 10% seed liquid for fermentation. The fermentation liquid passes through the anion exchange column, cation exchange column to change the pressure inside the columns to remove other impurities. After purification, it enters the decolorization tank, add activated carbon, decolorize to obtain clear liquid. The clear liquid enters the evaporation concentration device, such as plate evaporator or tubular evaporator, and can use MVR or TVR system to save energy consumption. Finally, obtain high-concentration citric acid clear liquid. Finally, the high-concentration citric acid liquid enters the crystallization tank for crystallization. Use a centrifuge to separate, the crystalline solid is dried by a dryer, and finally obtain industrialized citric acid solid.