Full Guide to SF6 Gas Recovery and Refilling: Operation Procedures and Precautions

Full Guide to SF6 Gas Recovery and Refilling: Operation Procedures and Precautions

SF6 gas, sulfur hexafluoride, is widely used in high – voltage switchgear (such as GIS, circuit breakers) due to its excellent insulation and arc – extinguishing properties. However, SF6 gas has an extremely high global warming potential, 23,900 times that of carbon dioxide. Therefore, the recovery, purification, and reuse of SF6 gas are of great importance. This article will introduce in detail the process of SF6 gas recovery and refilling, as well as relevant operation precautions.

1. Introduction to SF6 Gas Recovery Device

The SF6 gas recovery device is a specialized equipment used to recover and refill SF6 gas during the manufacturing and maintenance of SF6 electrical equipment. This device has multiple functions such as vacuum pumping, recovery and storage, filling and discharging, bottling, purification, and drying, which can meet the needs of SF6 gas recovery, purification, storage, and reuse in the power industry, chemical field, and laboratories.

2. SF6 Gas Recovery Process

‌Safety Inspection‌:

Confirm that the equipment is well – grounded and there are no leaks in the pipelines.

Check the power stability to ensure the normal operation of the equipment.

‌Connect Pipelines‌:

Connect the recovery device to the gas chamber interface of the power equipment using a pressure – resistant hose to ensure tightness.

‌Pretreatment‌:

If the gas is seriously polluted (such as arc decomposition), the type of impurities needs to be detected in advance for subsequent purification treatment.

‌Start the Compressor‌:

Pump the SF6 gas in the equipment into the recovery device and store it in a liquefied state through compression and condensation.

‌Monitor Pressure‌:

Observe the pressure gauge of the source equipment. Stop the recovery when the pressure approaches zero to avoid air ingress.

‌Filter Impurities‌:

The gas passes through purification equipment such as molecular sieves (to remove moisture) and alkaline filters (to remove acidic decomposition products) to remove impurities.

‌Detect Purity‌:

Use an SF6 purity analyzer to ensure that the purified gas meets the standards (such as IEC 60480).

‌Liquid Storage‌:

The purified SF6 is compressed and cooled into a liquid state and stored in a storage tank for subsequent filling.

3. SF6 Gas Refilling Process

‌Vacuum Pumping‌:

Perform vacuum pumping on the electrical equipment and pipelines to ensure there is no residual gas.

‌Filling Equipment‌:

Vaporize the liquid SF6 through a vaporizer and fill it into the power equipment to the rated pressure as required.

‌Pressure Monitoring‌:

Continuously monitor the pressure inside the equipment during the filling process to ensure the accuracy of the filling volume.

‌Safety Inspection‌:

After the filling is completed, conduct a safety inspection to ensure that there are no leaks in the equipment.

4. Operation Precautions

‌Safety Protection‌:

SF6 decomposition products are toxic. When operating, wear gas masks, goggles, and gloves.
Ensure good ventilation in the operation area to avoid long – term exposure to the SF6 gas environment.

‌Prohibit Air Ingress‌:

Control the pressure during recovery to prevent air from entering, which may cause liquefaction difficulties.
During the filling process, avoid gas leakage to ensure the filling purity.

‌Equipment Maintenance‌:

Regularly replace filters, check the compressor oil and seals to ensure the normal operation of the equipment.
Keep the equipment clean to avoid dust and impurities from entering.

‌Environmental Disposal‌:

Non – purifiable waste gas needs to be professionally treated and must not be directly discharged.Comply with relevant regulations to ensure that the recovery and reuse of SF6 gas meet environmental requirements.

The recovery and refilling of SF6 gas are indispensable and important links in the power industry, chemical field, and laboratories. Through professional SF6 gas recovery devices, the efficient recovery, purification, and reuse of SF6 gas can be achieved, reducing operating costs while reducing greenhouse gas emissions, which meets environmental requirements. During the operation process, it is necessary to strictly abide by safety regulations and operation precautions to ensure the safety of personnel and the normal operation of the equipment.