Lactic Acid Purification via Nanofiltration and Distillation
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Solution Overview
Problem
Conventional methods for isolating and purifying lactic acid from microbial fermentation broths result in lactic acid crystals with low purity due to poor solid-liquid separation performance.
Innovation Solution
A method involving nanofiltration of a lactic acid-containing aqueous solution to recover a permeate, followed by distillation to concentrate the lactic acid, and subsequent crystallization for improved solid-liquid separation and high-purity lactic acid crystal production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lactic acid is directly crystallized from fermentation broth without nanofiltration and distillation, then the process is simpler, but the solid-liquid separation performance is poor and purity is low
Solution Approach 1:
The patent applies preliminary action by performing nanofiltration and distillation before crystallization to pre-purify the lactic acid solution. This preliminary purification removes impurities that would otherwise interfere with crystallization, ensuring that the subsequent crystallization step produces high-purity crystals with excellent solid-liquid separation performance.
Solution Approach 2:
The patent segments the purification process into distinct stages: nanofiltration to remove small molecules and salts, distillation to concentrate and further purify lactic acid, and finally crystallization to produce pure solid crystals. This segmentation allows each step to optimize for its specific function, resulting in superior overall purification efficiency.
2Ease of operation
If conventional crystallization is used without nanofiltration and distillation, then the process is shorter, but the lactic acid crystals cannot be easily separated from liquid
Solution Approach 1:
The patent performs preliminary nanofiltration and distillation to remove impurities and concentrate lactic acid before crystallization. This preliminary action ensures that the crystals formed have excellent separation characteristics, making solid-liquid separation easy and efficient without requiring excessive process time.
3Manufacturing precision
If nanofiltration and distillation are performed before crystallization, then lactic acid purity and separation performance are improved, but the process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing nanofiltration and distillation before crystallization to pre-purify the lactic acid solution. This preliminary purification removes impurities that would otherwise interfere with crystallization, ensuring that the subsequent crystallization step produces high-purity crystals with excellent solid-liquid separation performance.
Solution Approach 2:
The patent segments the purification process into distinct stages: nanofiltration to remove small molecules and salts, distillation to concentrate and further purify lactic acid, and finally crystallization to produce pure solid crystals. This segmentation allows each step to optimize for its specific function, resulting in superior overall purification efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves lactic acid crystals with high purity and excellent solid-liquid separation performance, enhancing the quality of lactic acid for use in producing polylactic acid with superior physical properties.
Implementation Method 1
filtering a lactic acid-containing aqueous solution through a nanofiltration membrane to recover an aqueous lactic acid solution from the permeate side
Implementation Method 2
distilling the aqueous lactic acid solution to recover lactic acid from the vapor side
Implementation Method 3
crystallizing the lactic acid obtained in Step B, and performing solid-liquid separation to recover a lactic acid crystal(s)
Data Source
AI summary
A method of producing lactic acid includes filtering a lactic acid-containing aqueous solution through a nanofiltration membrane to recover an aqueous lactic acid solution from the permeate side (Step A); distilling the aqueous lactic acid solution to recover lactic acid from the vapor side (Step B); and crystallizing the lactic acid obtain in Step B, and performing solid-liquid separation to recover a lactic acid crystal(s) (Step C).