COF2 Purification via Two-Stage Rectification
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Solution Overview
Problem
The purification of carbonyl fluoride (COF2) is challenging due to its close boiling points with impurities like CO2 and HCl, making separation difficult, and existing methods are inefficient in achieving high purity and safety while being economical.
Innovation Solution
A two-stage rectification process is employed, involving preliminary and secondary purification by rectification under specific temperature and pressure conditions, using a rectification tower with appropriate fillers and materials resistant to carbonyl fluoride and hydrogen fluoride, to effectively separate and purify COF2 from impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional purification methods are used, then the purification process is simple, but the separation efficiency is low due to close boiling points of COF2 and impurities like CO2 and HCl
Solution Approach 1:
The purification process is divided into multiple sequential stages: preliminary purification to remove most impurities, followed by fine purification to achieve high purity COF2. This segmentation allows each stage to target specific impurities with optimized conditions, improving overall separation efficiency despite the close boiling points of COF2 and impurities like CO2 and HCl.
Solution Approach 2:
The patent employs dynamic adjustment of operational parameters including temperature gradients, pressure conditions, and gas flow rates during the rectification process. By dynamically optimizing these parameters based on the specific impurity composition and concentration, the system achieves efficient separation of COF2 from impurities with similar boiling points while maintaining process adaptability.
2Manufacturing precision
If high purity COF2 is achieved through multiple purification stages, then the purity reaches ≥99%, but the process time and operational complexity increase
Solution Approach 1:
The preliminary purification stage is designed to remove the majority of impurities before the fine purification stage. By performing this preliminary removal action first, the subsequent fine purification stage operates on a more concentrated COF2 stream, reducing the time and complexity required to achieve the final ≥99% purity level.
Solution Approach 2:
The patent utilizes controlled changes in temperature and pressure parameters across different purification stages to optimize separation efficiency. By adjusting these parameters to match the specific boiling point differences between COF2 and remaining impurities at each stage, the process achieves high purity output while minimizing unnecessary processing time.
3Manufacturing precision
If standard rectification equipment is used, then the device structure is simple, but it cannot effectively handle the close boiling point separation of COF2 and impurities
Solution Approach 1:
The patent introduces specialized rectification tower structures with optimized internal components such as packing materials and tray designs that act as intermediaries to enhance mass transfer efficiency. These structural modifications create additional surface area and contact points for vapor-liquid interaction, enabling effective separation of COF2 from impurities with close boiling points without requiring excessively complex equipment.
Solution Approach 2:
The rectification equipment design incorporates multi-dimensional separation approaches including vertical temperature gradients, horizontal gas flow distribution, and radial heat transfer surfaces. By utilizing multiple spatial dimensions for the separation process, the system achieves enhanced separation capability for close-boiling-point mixtures while maintaining reasonable equipment footprint and structural complexity.
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 process achieves a COF2 purity of ≥99% or higher, significantly reducing CO2 impurities to less than 1000 ppm, making it suitable for semiconductor manufacturing and other applications in a safer and more economical manner.
Implementation Method 1
A two-stage rectification process is employed, involving preliminary and secondary purification by rectification under specific temperature and pressure conditions
Implementation Method 2
the temperature at the bottom of a purification device ranges from -112°C to -48°C... and the temperature at the top is 0.5°C to 30°C lower than that at the bottom
Data Source
Figure 1
AI summary
The present invention relates to the technical field of fluoride chemical industry and electronic industry gas, and provides a carbonyl fluoride purification method. The purification method comprises: performing light component removal and heavy component removal for COF2 crude product gas, wherein during light component removal, the temperature at the bottom of a purification device ranges from -112°C to -48°C and the pressure ranges from 0.01 MPa to 0.6 MPa, and the temperature at the top is lower than that at the bottom by 0.5-30°C; and during the heavy component removal, the temperature at the bottom of the purification device ranges from -81°C to 80°C and the pressure ranges from 0.01 MPa to 0.6 MPa, and the temperature at the top is lower than that at the bottom by 0.5-30°C, to obtain preliminarily rectified mixed gas; and then performing rectification and purification once again, wherein the temperature at the bottom of the purification device ranges from -123°C to -36°C and the pressure ranges from 0.01 MPa to 1.03 MPa, and the temperature at the top is lower than that at the bottom by 0.2-45°C, to obtain purified gas. The purified gas is especially applicable to purification of COF2 crude product gas containing much CO2, the purity of COF2 in the purified gas is greater than or equal to 99%, and the CO2 content is less than 1000 ppm.