Membrane Unit for Vacuum Separation of Hydrofluoric Acid Gas
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Solution Overview
Problem
Wastewater containing fluorine, particularly from semiconductor manufacturing processes, poses challenges due to corrosion and environmental pollution, requiring an effective and environmentally friendly treatment and recycling method.
Innovation Solution
A method and apparatus involving a membrane unit with a hollow membrane that separates and recovers hydrofluoric acid gas from wastewater through vacuum application, followed by a scrubbing process using sweep gas and metal oxides/hydroxides to form high-purity metal fluoride, facilitating efficient recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional wastewater treatment methods are used, then treatment capacity is achieved, but corrosion of equipment and environmental pollution occur due to hydrofluoric acid
Solution Approach 1:
The patent extracts hydrofluoric acid from wastewater using a membrane separation unit before the wastewater enters treatment equipment. The membrane unit selectively permeates HF molecules from the liquid phase, concentrating them in a permeate stream while leaving treated water in the retentate stream. This extraction prevents corrosion of downstream equipment and reduces environmental pollution by isolating the harmful substance.
Solution Approach 2:
The patent introduces a membrane separation unit as an intermediary between wastewater storage and treatment processes. This intermediary component selectively removes HF before it contacts treatment equipment, thereby protecting equipment from corrosion while enabling subsequent treatment steps to proceed safely and effectively.
2Object-affected harmful factors
If hydrofluoric acid is removed from wastewater, then environmental pollution is reduced, but recovery and recycling of fluorine resources are not achieved
Solution Approach 1:
The patent simultaneously discards HF from the wastewater stream while recovering it in concentrated form through membrane separation. The permeate stream containing concentrated HF is directed to a separate handling system where it can be processed further for fluorine resource recovery, such as conversion to calcium fluoride or other useful fluorine compounds, thus preventing both pollution and resource loss.
Solution Approach 2:
The patent changes the concentration parameter of HF by using membrane separation to concentrate it from dilute wastewater to a higher concentration in the permeate stream. This parameter change enables the separated HF to be suitable for recovery processes and resource utilization, transforming it from a pollutant into a recoverable resource.
3Measurement precision
If membrane separation is used to remove hydrofluoric acid, then separation efficiency is improved, but operating cost increases due to vacuum application
Solution Approach 1:
The patent employs porous membrane materials with specific pore sizes and properties that enable selective permeation of HF molecules. These porous membranes facilitate separation based on molecular size and affinity differences, achieving high separation efficiency while requiring less energy for vacuum application compared to non-porous membrane systems.
Solution Approach 2:
The patent optimizes operating parameters such as vacuum pressure, feed flow rate, and membrane temperature to enhance separation efficiency while minimizing energy consumption. By carefully controlling these parameters, the system achieves effective HF removal with reduced vacuum energy requirements.
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 effectively reduces contaminants, achieves high-purity metal fluoride production, and enhances the recycling of fluorine, offering an environmentally friendly solution compared to conventional methods.
Implementation Method 1
a pump connected to the membrane unit and configured to apply a vacuum to an inner surface of the membrane such that hydrofluoric acid (HF) gas from the wastewater disposed within the membrane unit moves through the membrane onto the inner surface of the membrane
Implementation Method 2
recovering hydrofluoric acid gas by evaporating hydrofluoric acid (HF) in the wastewater based on a vacuum applied to the inner surface of the membrane
Implementation Method 3
a scrubbing unit connected to the membrane unit and configured to react hydrofluoric acid gas recovered from the membrane unit with a metal oxide or a metal hydroxide to form a metal fluoride
Data Source
AI summary
A method for treating wastewater containing fluorine is disclosed. The method for treating wastewater includes applying a vacuum to a membrane unit including a membrane having a hollow, injecting wastewater into the membrane unit so that the wastewater contacts an outer surface of the membrane, recovering hydrofluoric acid gas by evaporating hydrofluoric acid (HF) in the wastewater based on a vacuum applied to the inner surface of the membrane and moving the evaporated hydrofluoric acid (HF) to the inner surface through the membrane, injecting sweep gas into the membrane unit to discharge hydrofluoric acid gas remaining on the inner surface of the membrane, and forming a metal fluoride by reacting the recovered hydrofluoric acid gas with a metal oxide or metal hydroxide using a scrubbing process.