What Safety Regulations Need to Be Followed During the SF6 Gas Recovery Process?

SF6 gas is widely used in the power industry due to its excellent insulation and arc – extinguishing properties. However, it is a strong greenhouse gas, and improper handling during recovery can not only cause environmental pollution but also pose serious threats to human health and equipment safety. Therefore, strictly abiding by safety regulations during the SF6 gas recovery process is of great significance. This article will detail the key safety regulations that must be followed to ensure the safety and environmental protection of the entire recovery process.

Compliance with International and National Environmental Protection Regulations

First and foremost, the SF6 gas recovery process must comply with international and national environmental protection laws and standards. Internationally, the Kyoto Protocol clearly lists SF6 as a controlled greenhouse gas and requires signatory countries to take measures to reduce its emissions. At the national level, different countries have formulated corresponding regulations. For example, in the European Union, the F – Gas Regulation (Regulation (EU) 2014/517) sets strict limits on the emission of fluorinated gases including SF6, specifying that the recovery rate of SF6 gas from electrical equipment must reach at least 95% to minimize emissions. In the United States, the Environmental Protection Agency (EPA) has issued relevant guidelines, requiring enterprises to record the amount of SF6 gas used, recovered, and emitted, and report it regularly. In China, the “14th Five – Year Plan” for the Prevention and Control of Greenhouse Gas Emissions also includes SF6 in the key control scope, and the GB/T 36066 – 2018 “Technical Specifications for Recovery, Recycling and Reuse of Sulfur Hexafluoride Gas in Electrical Equipment” clearly stipulates the technical requirements and safety standards for SF6 gas recovery. Enterprises must familiarize themselves with and strictly implement these regulations to avoid legal risks and environmental damage.

Strict Implementation of On – site Operation Safety Specifications

On – site operation safety is a crucial link in the SF6 gas recovery process. Operators must follow strict operating procedures to ensure personal safety and the smooth progress of the recovery work.

• First, before starting the recovery operation, it is necessary to conduct a comprehensive inspection of the SF6 gas recovery equipment. Check whether the equipment is in good working condition, whether the pipelines are connected tightly without leakage, whether the pressure gauge, vacuum gauge, and other instruments are accurate and sensitive, and whether the safety valves are in normal working condition. If any fault or abnormality is found, the operation can only be started after timely maintenance and repair.
• Second, during the recovery process, it is necessary to control the recovery speed and pressure strictly. The recovery speed should not be too fast to avoid excessive pressure in the equipment and pipelines, which may lead to pipeline rupture or equipment damage. At the same time, the pressure in the recovery system should be monitored in real – time. When the pressure exceeds the specified limit, the operation should be stopped immediately, and the cause should be found out and handled. In addition, the temperature of the equipment should also be paid attention to. If the equipment overheats, it may affect the recovery efficiency and even cause safety accidents. Therefore, effective cooling measures should be taken to keep the equipment at a normal working temperature.
• Third, operators must wear appropriate personal protective equipment (PPE) during the operation. SF6 gas is colorless, odorless, and non – toxic, but when it is decomposed under high temperature or electric arc, it will produce toxic gases such as sulfur dioxide (SO2), hydrogen fluoride (HF), and sulfur tetrafluoride (SF4), which are harmful to the respiratory system, eyes, and skin of the human body. Therefore, operators must wear a full – face gas mask with an SF6 gas filter cartridge, chemical – resistant gloves, and protective clothing to prevent toxic gases from entering the human body through the respiratory tract or skin. In addition, the operation site should be well – ventilated. If the operation is carried out in a closed or semi – closed space, a forced ventilation system should be installed to ensure that the concentration of SF6 gas and its decomposition products in the air is lower than the allowable limit. According to the GBZ 2.1 – 2019 “Occupational Exposure Limits for Hazardous Factors in the Workplace Part 1: Chemical Hazardous Factors”, the time – weighted average allowable concentration of SF6 in the workplace is 6000mg/m³, and the short – term contact allowable concentration is 9000mg/m³. Operators should use a gas detector to monitor the gas concentration in the workplace in real – time. If the concentration exceeds the standard, the operation should be stopped immediately, and the personnel should be evacuated to a safe area.

Standardized Handling of Recovered SF6 Gas and Waste

After the SF6 gas recovery is completed, the recovered gas and the generated waste must be handled in a standardized manner to avoid secondary pollution.
First, the recovered SF6 gas should be purified and tested. The recovered gas may contain impurities such as air, moisture, and decomposition products. If it is directly reused without purification, it will affect the insulation performance of electrical equipment and shorten the service life of the equipment. Therefore, the recovered SF6 gas should be purified using a professional purification device to remove impurities and moisture. After purification, the gas should be tested in accordance with the GB/T 12022 – 2014 “Sulfur Hexafluoride for Industrial Use” to ensure that its purity, moisture content, acidity, and other indicators meet the reuse requirements. Only the gas that passes the test can be stored in a special gas cylinder for reuse. The gas cylinder used for storing SF6 gas must meet the national safety standards, be marked clearly, and be inspected regularly in accordance with the regulations.
Second, the waste generated during the recovery process, such as the waste filter cartridge, waste oil, and waste gas that cannot be purified and reused, must be handled in accordance with the relevant environmental protection regulations. The waste filter cartridge and waste oil may contain toxic substances, so they should be collected and stored in a sealed container, and handed over to a qualified hazardous waste disposal unit for treatment. The waste gas that cannot be purified and reused should be treated using a professional waste gas treatment device to reduce its harm to the environment before being discharged. It is strictly forbidden to discharge the waste gas directly into the atmosphere.

Establishment of Emergency Response Mechanisms

In the SF6 gas recovery process, unexpected situations such as gas leakage, equipment failure, and personnel poisoning may occur. Therefore, it is necessary to establish a sound emergency response mechanism to deal with emergencies in a timely and effective manner, minimize the loss of personnel and property, and avoid the expansion of environmental pollution.

• First, enterprises should formulate a detailed emergency response plan for the SF6 gas recovery process. The plan should include emergency handling procedures for different types of emergencies, such as gas leakage, equipment fire, and personnel poisoning. It should also clarify the responsibilities of each department and personnel in the emergency response process, ensure that everyone knows their roles and responsibilities, and can take quick and effective measures in case of an emergency.
• Second, regular emergency drills should be carried out. Through emergency drills, operators can be familiar with the emergency response procedures and skills, improve their ability to deal with emergencies, and find and solve problems in the emergency response plan in a timely manner. The frequency of emergency drills should be determined according to the actual situation of the enterprise, but generally, it should not be less than once a year.
• Third, necessary emergency rescue equipment and materials should be prepared at the operation site. For example, gas leak detectors, fire extinguishers, first – aid kits, and emergency evacuation routes should be set up. The emergency rescue equipment and materials should be checked and maintained regularly to ensure that they are in good working condition and can be used normally in case of an emergency.

In conclusion, the SF6 gas recovery process involves many safety risks, and strictly abiding by relevant safety regulations is the key to ensuring the safety and environmental protection of the entire process. Enterprises should strengthen the training of operators, improve their safety awareness and operational skills, strictly implement international and national environmental protection regulations and on – site operation safety specifications, standardize the handling of recovered gas and waste, and establish a sound emergency response mechanism. Only in this way can we minimize the safety risks and environmental pollution caused by the SF6 gas recovery process and promote the sustainable development of the power industry.