Polyether Polyol Refining via Hydrophilic Medium Separation
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Solution Overview
Problem
The existing refining process for polyether polyol is complex, time-consuming, and results in low yield due to the need for multiple steps and long dehydration times, leading to polyether polyol loss and unqualified polyurethane products when high levels of metal ions like potassium and sodium are present.
Innovation Solution
A refining method involving neutralization or dilution of crude polyether polyol to create a mixed solution, which is then flowed through a hydrophilic medium to separate into distinct density phases, allowing for the effective removal of alkaline metal ions and water without additional filtration or adsorption steps, using a refining apparatus with a mixing unit and a salt removal device to facilitate this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If neutralization-filtration method is used to remove metal ions, then metal ion removal effect is improved, but processing steps become complex and treatment time increases
Solution Approach 1:
The patent combines multiple refining operations (neutralization, dehydration, filtration) into a single integrated reactor vessel. The reactor simultaneously performs chemical neutralization of metal ions and physical separation through controlled precipitation, eliminating the need for separate processing units and reducing overall process complexity.
Solution Approach 2:
The reactor is designed as a multi-functional device that can perform neutralization, dehydration, and filtration operations within a single vessel. By making the reactor universal in its capabilities, the patent eliminates the need for multiple specialized equipment pieces, thereby simplifying the overall processing system while maintaining effective metal ion removal.
2Manufacturing precision
If long dehydration time is used to improve crystal particle size, then filtering effect is improved, but treatment time increases and polyether polyol loss occurs
Solution Approach 1:
The patent changes key process parameters including temperature control during dehydration and the use of specific anti-caking agents. By optimizing these parameters, the method achieves rapid formation of filterable crystal particles without requiring prolonged dehydration times, thus reducing both treatment time and polyether polyol loss while maintaining effective filtering.
3Manufacturing precision
If vacuum dehydration is carried out to crystallize alkali metal salts, then metal ion removal is improved, but polyether polyol loss increases due to large viscosity
Solution Approach 1:
The patent introduces anti-caking agents as intermediaries that modify the physical properties of alkali metal salt crystals during dehydration. These agents prevent excessive crystal aggregation and reduce adhesion to equipment surfaces, thereby minimizing polyether polyol loss during the vacuum dehydration process while still achieving effective metal ion removal through crystallization.
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 method simplifies the refining process, reduces treatment time and costs, minimizes polyether polyol loss, and produces a high-quality refined polyether polyol with low aldehyde content and minimal odor, suitable for direct use in polyurethane synthesis.
Implementation Method 1
flowing the mixed solution through a hydrophilic medium to aggregate same into a first density phase liquid and a second density phase liquid
Implementation Method 2
the aqueous phase droplets in the mixed solution are adsorbed on the surface of the hydrophilic medium and continuously aggregate on the surface of the hydrophilic medium along with circulation of the mixed solution
Implementation Method 3
after a certain volume is reached, the aqueous phase droplets are separated from the hydrophilic medium under the action of gravity, so as to form a first density phase liquid
Data Source
AI summary
Disclosed in the present invention is a polyether polyol refining method, comprising (1) neutralising or diluting crude polyether polyol to obtain a mixed solution; (2) flowing the mixed solution through a hydrophilic medium to aggregate same into a first density phase liquid and a second density phase liquid, the first density phase liquid being an aqueous solution containing alkaline metal ions and/or alkaline earth metal ions, and the second density phase liquid being polyether polyol; and (3) allowing the first density phase liquid to settle and separating same from the second density phase liquid to obtain refined polyether polyol. In the present refining method, using the hydrophilic medium for one-step removal of the alkaline ions and water in the polyether polyol simplifies the treatment steps, increases treatment efficiency, and can prevent polyether polyol loss; the obtained polyether polyol has low alkaline ion content and little odour. Also disclosed in the present invention is a polyether polyol refining apparatus, comprising a mixing unit and a separating unit, and being capable of refining polyether polyol with low alkaline ion content and little odour.