| 摘要 |
Provided is a cleaning process of producing lactic acid. Firstly saccharification liquid is prepared through saccharated materials, then fermented with nutritive materials and lactic acid bacteria, and liquid alkali is used to adjust the pH. The fermentation broth is filtrated with porous membrane, and the lactic acid bacteria in the interception liquid are then reintroduced into the porous membrane for recycling. The permeate from porous membrane is subjected to nanofiltration to be decolored and purified. The concentrated solution from nanofiltration and the cleaning liquid from fermentation tank and its affiliated equipment are filtrated and sterilized by using ceramic membrane, and then are reintroduced into the fermentation unit for recycling. The permeate from nanofiltration is then subjected to bipolar electrodialysis system to prepare lactic acid, and the liquid alkali produced at the same time is reintroduced into the fermentation tank for recycling. The lactic acid is finally concentrated by using vacuum distillation. The process recycles the bacteria in the liquid alkali and matured fermentation broth, and is characterized by low material consumption and emission, low pollution, reduced cost and cleanness and environmentally protection of the whole production process.
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