What are the application areas of sulfur hexafluoride?- SF6在线监测系统_SF6检漏仪_SF6传感器_SF6密度继电器

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What are the application areas of sulfur hexafluoride?

发布时间：2018-03-10 来源：ydlcb 浏览次数：38次

Before the use of sulfur hexafluoride gas, we first understand the basic properties of SF6 gas. SF6 gas has a history of more than 100 years, it was synthesized by two French chemists, Moissan and Lebeau, in 1900, and made commercially available in 1947. Sulfur hexafluoride is a volatile compound. Yellow-brown at room temperature, reddish brown in liquid and gas. Strong alpha radioactivity. Melting point 50.75℃. Boiling point 62.3℃. It does not sublimate at atmospheric pressure, but unlike uranium hexafluoride, it can change from a liquid to a gas. It's a strong oxidizing agent. Trace water vapor quickly hydrolyzes it to plutoniumyl fluoride (PuO2F2). Pure SF6 gas is a colorless, odorless, basically non-toxic, non-combustible halogen compound. Its relative density is 6.16g/cm3(20℃,0.1MPa) in the gaseous state and 1400g/cm3(20℃) in the liquid state. SF6 gas has very stable chemical properties, does not burn in the air, does not support combustion, and does not react with water, strong alkali, ammonia, hydrochloric acid, sulfuric acid, etc. At temperatures below 150 ° C, SF6 gas is chemically inert and rarely melts in water and slightly melts in alcohol.

The various uses of sulfur hexafluoride gas are based on what characteristics of sulfur hexafluoride gas? The reason why SF6 gas is suitable for power equipment is its strong electronegativity, excellent arc extinguishing performance, high insulation strength, and 3 times that of air at atmospheric pressure. Under normal atmospheric pressure, the breakdown voltage value of sulfur hexafluoride is more than 2.5-3 times that of air, and the arc extinguishing ability is higher than 100 times that of air. The heat conductivity is good and easy to compound, especially when SF6 gas dissociates due to discharge or arc action. In addition, SF6 gas can be stored in small tanks, because it is easy to liquefy at high pressure at room temperature.

What are the uses of sulfur hexafluoride gas? Which industries use SF6 gas? SF6 is currently used in electrical engineering, semiconductor processing, filling gas for magnesium purification, preparation of sound insulation materials, leak detection, silent propulsion of torpedoes, etc. Sulfur hexafluoride is widely used in circuit breakers, high-voltage transformers, gas-closed capacitors, high-voltage transmission lines, transformers and other equipment because of its good insulation performance and arc extinguishing performance. Electronic grade high purity sulfur hexafluoride is an ideal electronic etching agent, which is widely used in the field of microelectronics technology. As a refrigerant, the refrigeration range can be between -45 ° C and 0 ° C. The electrical industry uses its high dielectric strength and good arc extinguishing performance as an insulating material for high voltage switches, large capacity transformers, high voltage cables and gases. The mining industry is used as a reverse adsorbent to replace oxygen in mine coal dust. High purity SF6 is also widely used in metal smelting (such as magnesium alloy melting furnace protective gas), aerospace, medical (X-ray machine, laser machine), meteorology (tracer analysis), chemical (advanced automobile tires, new fire extinguishers) and so on.

Sulfur hexafluoride circuit breaker is a kind of circuit breaker which uses sulfur hexafluoride gas as arc extinguishing medium and insulating medium. The use of sulfur hexafluoride as an arc extinguishing gas medium in circuit breakers began in the early 1950s. Due to the excellent characteristics of sulfur hexafluoride gas, the single break of sulfur hexafluoride circuit breaker is much higher than that of compressed air circuit breaker and less oil circuit breaker in terms of voltage and current parameters, and does not require high air pressure and a considerable number of series breaks. In the 1960s and 1970s,SF6 circuit breakers have been widely used in ultra-high voltage and large capacity power systems. In the early 1980s, SF6 circuit breakers with 363 kV single break, 550 kV double break and rated breaking current of 80 and 100 kV were successfully developed.

Sulfur hexafluoride is a colorless, odorless, non-combustible, non-reactive, relatively non-toxic, asphyxiating liquefied gas. Liquefied bottled gas at its vapor pressure (202.78 kgf/cm2 @21.1°C). Sulfur hexafluoride is widely used in the electrical industry for its good insulation and arc extinguishing performance, such as: circuit breakers, high voltage switches, high voltage transformers, gas closed combination capacitors, high voltage transmission lines, transformers, etc. SF6 is also widely used in metal smelting (such as magnesium alloy melting furnace protective gas), aerospace, medical (X-ray machine, laser machine), meteorology (tracer analysis), chemical (advanced automobile tires, new fire extinguishers) and so on. Electronic grade high purity sulfur hexafluoride is an ideal electronic etching agent, which is widely used in the field of microelectronics technology. With the development of today's science and technology, the fields involved in SF6 continue to expand, and are widely used in more and more basic fields and scientific and technological fields. In the refrigeration industry, sulfur hexafluoride is used as a refrigerant, and the cooling range can be between -45 ° C and 0 ° C.

Sulfur hexafluoride SF6 has excellent electrical insulation, and the electrical insulation capacity is about 2.5 times that of air and nitrogen. Sulfur hexafluoride has good arc extinguishing performance, its arc extinguishing ability is about 100 times that of air, and the chemical properties of sulfur hexafluoride are very stable, so sulfur hexafluoride is widely used as an insulating gas, such as sulfur hexafluoride relay, sulfur hexafluoride high voltage circuit breaker, sulfur hexafluoride interconductance sensor, sulfur hexafluoride lightning arrester and so on. Sulfur hexafluoride has become a new generation of insulating media with good insulation and high pressure resistance after insulating oil.

In the smelting process of magnesium alloy and magnesium aluminum alloy, sulfur hexafluoride gas or a mixture of sulfur hexafluoride and nitrogen gas is often used as a protective gas to prevent magnesium metal and its alloys from being oxidized by air.

In TFT-LCD panel factories and other microelectronics industries, sulfur hexafluoride is commonly used as a cleaning gas and etching gas, and in the production process of optical fiber, sulfur hexafluoride is also commonly used as a dopant for the isolation layer of single film fiber.

Sulfur hexafluoride is commonly used as a tracer in the field of air pollution monitoring and hydrogeological detection. Because sulfur hexafluoride is non-toxic, safe, stable in nature, reliable in testing methods, and less in air and water, sulfur hexafluoride is often used as a gas tracer, and the missing range of sulfur hexafluoride can reach 100km.

In the medical industry, sulfur hexafluoride is also used in contrast ultrasound, mainly for liver tumors. In the CEUS process, sulfur hexafluoride is mainly used as a safe contrast agent. After intravenous injection of sulfur hexafluoride, the gas is dissolved in the blood, and half of the sulfur hexafluoride gas can be excreted by breathing every 12 minutes.

In addition, due to the stable chemical properties of hexafluoride and large molecular weight (molecular weight of sulfur hexafluoride 146.06), its density is 5.11 times that of air, and when it is filled into car tires or basketball and football, it will be able to maintain long-term stability of air pressure.

Matters needing attention

Sulfur hexafluoride should be stored in a cool, ventilated warehouse. Keep away from fire and heat. The storage temperature should not exceed 50℃. It should be stored separately from easy (can) combustibles and oxidants, and should not be mixed. Storage area should be equipped with leakage emergency treatment equipment. Closed operation, local exhaust. Operators must be specially trained and strictly abide by the operating procedures. It is recommended that operators wear a filter gas mask (half mask). Keep away from flammable and combustible materials. Prevents gas leakage into the workplace air. Avoid contact with oxidants. Light loading and unloading during handling to prevent cylinder and accessories damage. Equipped with leak emergency treatment equipment. Bottled gas products are high-pressure filled gas, which should be used after decompression and decompression. The packaged gas cylinder has a service life, and the expired gas cylinder must be sent to a department for safety inspection before it can continue to be used. When each bottle of gas is used to exhaust gas, the residual pressure in the bottle should be kept at 0.5MPa, and the minimum residual pressure should not be lower than 0.25MPa, and the bottle valve should be closed to ensure the quality of the gas and the safety of use. Bottled gas products in transportation, storage, use should be classified stacking, flammable gas and combustion gas stacking together, not near the open fire and heat sources, should be done not near the fire, do not touch oil wax, do not explode, do not throw, do not impact, is strictly prohibited in the cylinder arc or arc, is strictly prohibited rough loading and unloading.