Polyarylene Sulfide Solvent Recovery via Compression Heating
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Solution Overview
Problem
Current methods for recovering organic amide solvents from washing wastewater in polyarylene sulfide manufacturing are energy-intensive and costly, particularly when using water as a solvent, making resource saving and cost reduction difficult.
Innovation Solution
The method involves increasing the temperature of distilled vapor or a heat medium exchanged with it, followed by heating to separate and concentrate the organic amide solvent, allowing for its efficient recovery without additional organic solvents and reducing water usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If direct distillation of washing wastewater is used to recover organic amide solvent, then solvent recovery is achieved, but large amount of energy is required due to water evaporation
Solution Approach 1:
The washing wastewater is divided into two phases through addition of a water-immiscible organic solvent: an organic amide solvent layer and a water layer. This segmentation allows separate handling and recovery of the organic amide solvent without requiring evaporation of the entire water volume, significantly reducing energy consumption.
Solution Approach 2:
A water-immiscible organic solvent is introduced as an intermediary substance to facilitate the separation of organic amide solvent from water. This intermediary enables phase separation and allows the organic amide solvent to be recovered in a concentrated form without direct evaporation from the aqueous waste stream.
2Ease of manufacture
If water is used as washing solvent, then cost reduction and resource saving are difficult due to high energy consumption for evaporation
Solution Approach 1:
Instead of directly evaporating water to recover the organic amide solvent, the method uses a water-immiscible organic solvent to create a separate phase where the organic amide solvent can be recovered. This indirect approach 'copies' the recovery process through phase separation rather than direct evaporation, reducing energy requirements and manufacturing costs.
3Quantity of substance
If organic solvent extraction is used to recover organic amide solvent, then solvent recovery is achieved, but process complexity and facility costs increase
Solution Approach 1:
The method uses a water-immiscible organic solvent that forms a distinct phase with the organic amide solvent, creating a homogeneous organic phase that can be easily separated from the water phase. This homogeneous phase formation simplifies the recovery process compared to complex extraction procedures requiring multiple solvents and separation steps.
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 low-energy recovery of organic amide solvents and reduces water consumption, enhancing resource efficiency and lowering costs in polyarylene sulfide manufacturing.
Implementation Method 1
increasing the temperature of distilled vapor or a heat medium exchanged with it
Implementation Method 2
a heat medium exchanged with it
Implementation Method 3
separating and concentrate the organic amide solvent
Data Source
AI summary
To provide a method of manufacturing polyarylene sulfide (PAS) while efficiently recovering an organic amide solvent at a low energy cost, without using an organic solvent, from washing wastewater produced by washing a raw material mixture containing PAS and an organic amide solvent using a solvent containing water; a method of manufacturing PAS by reducing the amount of water supplied when washing the raw material mixture using a solvent containing water; and PAS manufactured by these methods. A method according to the present invention includes: a step of mixing a solvent containing water and a raw material mixture that contains PAS and an organic amide solvent, and then washing the PAS; a step of obtaining a separated liquid by solid-liquid separation; and a step of separating the separated liquid into distilled vapor having a smaller amount of the organic amide solvent and a recovered liquid having a larger amount of the organic amide solvent by heating, where the heating is performed utilizing an increase in temperature based on compressing the distilled vapor and/or compressing a heat medium heat-exchanged with the distilled vapor.