Lactic Acid Crystallization Yield via Distillation Segmentation
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Solution Overview
Problem
The existing methods for producing high-purity lactic acid from microbial fermentation broths face challenges in achieving high yield and stability due to accumulation of multimeric lactic acid and impurities in the recycle system during crystallization, leading to decreased crystallization yield.
Innovation Solution
A method involving distillation to collect lactic acid from the vapor side, followed by crystallization and solid-liquid separation, with the mother liquor circulated back to the crystallization step, effectively preventing accumulation of multimeric lactic acid and impurities, thereby stabilizing the production of high-purity lactic acid crystals with a high yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lactic acid is recovered from fermentation broth by crystallization with mother liquor recycling, then lactic acid yield is improved, but multimeric lactic acid and impurities accumulate in the recycle system causing decreased crystallization yield
Solution Approach 1:
The patent divides the mother liquor recycling process into two distinct streams: a main recycling stream that returns to the crystallization step, and a side stream that undergoes distillation to remove multimeric lactic acid and impurities. This segmentation allows the system to maintain high yield through recycling while preventing accumulation of harmful substances through periodic purification.
Solution Approach 2:
The patent changes the physical-chemical parameters of the mother liquor by subjecting a portion to distillation, which alters the concentration and composition of multimeric lactic acid and impurities. This parameter change enables the removal of accumulated substances while preserving the beneficial components for recycling.
2Reliability
If distillation is performed on lactic acid-containing solution, then multimeric lactic acid and impurities are removed, but production process complexity increases
Solution Approach 1:
Instead of distilling the entire mother liquor stream, the patent applies distillation to only a side stream (partial action). This approach is sufficient to remove multimeric lactic acid and impurities from the recycling system without the excessive complexity and cost of processing the complete flow, achieving the desired purification effect with minimal additional process complexity.
3Productivity
If mother liquor is recycled to crystallization step, then lactic acid recovery efficiency is improved, but impurity accumulation occurs reducing product purity
Solution Approach 1:
The patent introduces distillation as an intermediary purification step in the mother liquor treatment pathway. This intermediary process selectively removes multimeric lactic acid and impurities before the purified stream rejoins the main recycling loop, thereby maintaining both high recovery efficiency and high product purity simultaneously.
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
This approach enables stable and efficient production of high-purity lactic acid with a high yield by suppressing oligomerization and impurity accumulation, enhancing the crystallization process and maintaining the quality of lactic acid crystals.
Implementation Method 1
subjecting a lactic acid-containing solution to distillation to collect lactic acid from the vapor side
Implementation Method 2
lactic acid is precipitated as crystals to increase the chemical purity as well as the optical purity of the lactic acid
Implementation Method 3
subjecting the lactic acid slurry obtained in Step A to solid-liquid separation into lactic acid crystals and a mother liquor
Data Source
AI summary
A method of producing lactic acid includes subjecting a lactic acid-containing solution to distillation to collect lactic acid from the vapor side (Step A); subjecting the lactic acid obtained in Step A to crystallization (Step B); subjecting the lactic acid slurry obtained in Step B to solid-liquid separation into lactic acid crystals and a mother liquor (Step C); and circulating the mother liquor obtained in Step C to Step B (Step D).