To ensure effective purification of sulfur hexafluoride (SF6) gas, a comprehensive approach is required—covering equipment performance, operational procedures, maintenance practices, and testing methods. Below are the key measures:

1. Use High-Performance Purification Equipment

• Multi-stage filtration system: Incorporate particulate filters, adsorbents (e.g., molecular sieves, activated alumina), and cryogenic condensers to effectively remove moisture, oil, decomposition byproducts (such as SO₂, HF, CF₄), and solid contaminants.

• High-efficiency adsorbents: Replace or regenerate adsorbents regularly to maintain their capacity for adsorbing moisture and acidic decomposition products.

• Vacuum degassing capability: Utilize high-vacuum conditions to facilitate the removal of residual impurities and moisture.

2. Strictly Control Operational Procedures

• Pre-treatment phase: Verify chamber pressure, temperature, and gas condition before recovery to prevent large amounts of liquid contaminants from entering the purification system.

• Staged purification process:

• Start with coarse filtration (to remove particles and oil mist);

• Follow with deep drying and chemical purification through adsorption columns;

• Apply cryogenic condensation or membrane separation if higher purity is required.

• Prevent secondary contamination: Use clean, dry hoses and connectors to avoid ingress of air or moisture.

3. Regular Maintenance and Calibration

• Inspect and replace filter elements and adsorbents periodically;

• Maintain critical components such as vacuum pumps, compressors, and valves;

• Calibrate sensors for pressure, humidity, and purity to ensure accurate monitoring data.

4. Post-Purification Gas Quality Testing

• Test purified SF6 gas according to international standards (e.g., IEC 60480, GB/T 12022). Key quality indicators include:

• Purity ≥ 99.9%

• Moisture content ≤ 8 μg/g (or ≤ 10 ppmv)

• Acidity ≤ 0.3 μg/g

• Hydrolyzable fluorides, mineral oil, and other impurities within specified limits

• Use portable SF6 gas analyzers for rapid on-site testing; conduct full laboratory analysis when necessary.

5. Personnel Training and Standardized Operations

• Operators should receive professional training on SF6 properties, equipment operation, and safety protocols;

• Strictly follow Standard Operating Procedures (SOPs) and maintain detailed records of recovery parameters, purification settings, and test results for each batch to ensure traceability.

By implementing these measures, the purification effectiveness of SF6 gas can be reliably guaranteed, meeting the high-purity requirements for reuse in electrical equipment (e.g., GIS, circuit breakers), thereby extending equipment service life and ensuring safe operation.