Deodorized 1,2-Propanediol Production via Segmented Distillation
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Solution Overview
Problem
1,2-propanediol produced from hydrogenated glycerol often contains impurities such as sulfuric acid, hydrogen sulfide, thioalcohols, and odor-intensive substances like thiols, fatty acids, esters, and ketones, making it unsuitable for certain applications due to its odor.
Innovation Solution
A distillation process involving a low boiler column A to separate off low-boiling impurities and a pure distillation column B to further purify 1,2-propanediol, achieving a high purity of at least 99.7% with minimal odor-intensive substances, using columns with specific plate configurations and reflux ratios, and optionally employing reducing phosphorus compounds to enhance separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple distillation process is used, then production cost is reduced, but purification effectiveness is insufficient and odor-intensive impurities remain
Solution Approach 1:
The distillation process is divided into two separate columns: Column A for removing low-boiling impurities (methanol, water, low-boiling odorous substances) and Column B for removing high-boiling impurities (ethylene glycol, glycerol, odor-intensive substances). This segmentation allows each column to be optimized for its specific separation task, achieving high purification effectiveness while maintaining reasonable production costs.
Solution Approach 2:
The patent introduces an intermediary stream between Column A and Column B, where the bottom stream from Column A (containing 1,2-propanediol with some impurities) serves as the feed for Column B. This intermediary approach allows progressive purification, where each column handles specific impurity ranges, balancing purification effectiveness with energy efficiency and cost.
2Manufacturing precision
If high reflux ratio is used in distillation, then separation precision is improved, but energy consumption increases
Solution Approach 1:
The energy-intensive distillation process is segmented into two columns with different reflux ratio requirements. Column A operates with lower reflux ratio for separating low-boiling components, while Column B uses higher reflux ratio for removing trace odor-intensive substances. This segmentation optimizes energy consumption by applying high energy input only where necessary for final purification.
Solution Approach 2:
The patent optimizes operating parameters for each column separately: Column A operates with reflux ratio and temperature settings optimized for low-boiling substance removal, while Column B uses different parameters for high-boiling impurity separation. This parameter optimization achieves high separation precision while minimizing overall energy consumption.
3Use of energy by moving object
If bottom temperature is kept low, then energy consumption is reduced, but separation efficiency decreases
Solution Approach 1:
The distillation process is segmented into two temperature zones: Column A operates at lower bottom temperatures suitable for removing low-boiling impurities without excessive energy input, while Column B operates at optimized temperatures for removing high-boiling odor-intensive substances. This segmentation allows each column to operate at energy-efficient temperatures while maintaining high separation efficiency for their respective impurity ranges.
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 process effectively removes impurities, resulting in deodorized 1,2-propanediol suitable for various applications, including dampening solutions, adhesives, coolants, food, pharmaceuticals, and cosmetics, with a significant reduction in odor-intensive substances and ethylene glycol concentration.
Implementation Method 1
the contaminated propanediol is first moved into a low boiler column A, which comprises a rectification section and a stripping section... the low boilers, in particular methanol, 1-propanol, 2-propanol, water and low-boiling odorous substances are separated off
Implementation Method 2
introduced into a column B for pure distillation... high boilers such as ethylene glycol and glycerol are separated off via the bottom
Data Source
Figure 1
AI summary
The present invention relates to a method for producing deodorized 1,2-propanediol, to the use of the purified propanediol, and to a device for performing the method.