Aromatic Dicarboxylic Acid Production via Hot Extraction
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Solution Overview
Problem
Current processes for producing aromatic dicarboxylic acids, such as terephthalic acid, are inefficient and costly due to the loss of valuable organic compounds and increased energy consumption in cooling and separation steps, which also result in the removal of potential reactants from the reaction system.
Innovation Solution
A process and apparatus that involves separating a vent gas into organic solvent-rich and water-rich streams, followed by an extraction stage where organic compounds are recovered from the aqueous purification mother liquor at elevated temperatures, allowing the reuse of the aqueous phase and reducing water usage, capital, and variable costs by avoiding intermediate cooling and separation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cooling and filtering process is used to separate PTA crystals from mother liquor, then product purity is improved, but heat loss increases and valuable organic compounds are removed from the reaction system
Solution Approach 1:
The invention changes the temperature parameter of the mother liquor from cooled state to heated state (at least 90°C) before extraction, allowing organic compounds to be extracted at elevated temperatures without causing heat loss from the system. This parameter change enables the extraction process to occur without the need for subsequent cooling steps, thereby eliminating heat loss while maintaining product purity.
Solution Approach 2:
The invention recovers valuable organic compounds from the mother liquor by extracting them with organic liquid at elevated temperatures. Instead of discarding the mother liquor after cooling and filtering, the process recovers organic compounds through extraction, returns the aqueous phase to the distillation stage, and recycles the organic phase to the oxidation stage, thereby preventing loss of both heat and valuable materials.
2Manufacturing precision
If cooling and filtering process is used to separate PTA crystals from mother liquor, then product purity is improved, but valuable organic compounds are removed from the reaction system
Solution Approach 1:
The invention recovers valuable organic compounds from the mother liquor by extracting them with organic liquid at elevated temperatures. Instead of discarding the mother liquor after cooling and filtering, the process recovers organic compounds through extraction, returns the aqueous phase to the distillation stage, and recycles the organic phase to the oxidation stage, thereby preventing loss of both heat and valuable materials.
Solution Approach 2:
The invention changes the temperature parameter of the mother liquor from cooled state to heated state (at least 90°C) before extraction, allowing organic compounds to be extracted at elevated temperatures without causing heat loss from the system. This parameter change enables the extraction process to occur without the need for subsequent cooling steps, thereby eliminating heat loss while maintaining product purity.
3Manufacturing precision
If intermediate cooling and separation steps are used, then product purity is improved, but process complexity and operational costs increase
Solution Approach 1:
The invention merges the extraction of organic compounds with the existing distillation and oxidation processes. The aqueous phase is returned to the distillation stage and the organic phase is returned to the oxidation stage, integrating multiple functions into existing process streams. This merging eliminates the need for separate cooling and separation equipment, thereby reducing process complexity while maintaining product purity.
Solution Approach 2:
The invention changes the temperature parameter of the mother liquor from cooled state to heated state (at least 90°C) before extraction, allowing organic compounds to be extracted at elevated temperatures without causing heat loss from the system. This parameter change enables the extraction process to occur without the need for subsequent cooling steps, thereby eliminating heat loss while maintaining product purity.
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 enhances the efficiency and economy of aromatic dicarboxylic acid production by recycling valuable organic compounds and reducing water usage, thereby lowering operational costs and maintaining high product purity.
Implementation Method 1
extracting said organic compounds from the aqueous purification mother liquor by contacting the aqueous purification mother liquor at a temperature of at least 90 °C with an organic liquid in the extraction stage to form an aqueous phase and an organic phase
Implementation Method 2
separating a vent gas from an oxidation stage into an organic solvent-rich liquid stream and a water-rich vapour stream in a distillation stage
Implementation Method 3
further comprising heating the organic liquid prior to its contact with the aqueous purification mother liquor
Data Source
Figure 1
AI summary
The present invention provides a process for the production of an aromatic dicarboxylic acid comprising the catalytic oxidation of a hydrocarbon precursor in an organic solvent, comprising the steps of: i) separating a vent gas from an oxidation stage into an organic solvent-rich liquid stream and a water-rich vapour stream in a distillation stage; and ii) separating an aqueous purification mother liquor comprising organic compounds from purified aromatic dicarboxylic acid crystals in a separation stage, characterised in that the process further comprises the steps of: iii) transferring the aqueous purification mother liquor from the separation stage to an extraction stage; iv) extracting said organic compounds from the aqueous purification mother liquor by contacting the aqueous purification mother liquor at a temperature of at least 90ºC with an organic liquid in the extraction stage to form an aqueous phase and an organic phase, wherein the concentration of said organic compounds in the aqueous phase is lower than the concentration of said organic compounds in the aqueous purification mother liquor; and v) transferring the aqueous phase to said distillation stage. The present invention further provides an apparatus for carrying out the process.