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What are the disadvantages of sulfur hexafluoride

SF6 was synthesized by two French chemists in 1900. Since the 1960s, SF6 has been widely used in high-voltage circuit breakers and transformer equipment in the power industry all over the world as an extremely superior explosion-proof and extinguishing medium. Today, SF6 gas has almost become the only medium in hV, UHV circuit breakers and GIS,but what is the Disadvantages of sf6 gas?

1. Physical and chemical properties of SF6 gas

Pure SF6 gas is colorless and odorless. Non-flammable, SU stable chemical properties at room temperature, layer of inert gas, is more than 5 times the proportion of air. However, SF6 gas will decompose under the influence of electric arc, partial discharge, high temperature and other factors, as SF6 gas mainly acts as plug - off and arc - extinguishing medium in power ticket system. Its decomposition material encounters water to become corrosive electrolyte, especially some high toxic decomposition material, such as SF4, S2F2.sof2, HF, SO2, etc., if inhaled in large quantities, it will cause head and lung edema, and even dizziness mystery and death.

In the relatively empty room, due to poor air circulation, SF6 and its decomposition products are accumulated indoors, and SF6 gas is colorless and tasteless, thus causing great harm to patrol maintenance personnel. When GIS produces leakage, SF6 gas accumulates in the lower space above the floor, resulting in local hypoxia and suffocation, resulting in major accidents.

2. SF6 switch room leakage hazard

Installation of SF6 high pressure equipment of the indoor space a 0^ specially closed, once the SF6 gas leakage, due to the air circulation is extremely slow, toxic decomposition in indoor deposition, not easy to discharge, so as to enter the SF6 switch room staff have a great danger, and, because the proportion of SF6 gas is larger than oxygen. When SF6 gas leakage occurs, SF6 gas lattice accumulates in the nong space, resulting in local oxygen. Suffocate. On the other hand, since SF6 gas itself is colorless and odorless, it is not easy to be detected after leakage, which increases the potential danger to the workers entering the leakage site, seriously threatens the safety and health of personnel, and even causes vicious accidents.

3. Disadvantages of sf6 gas

According to the United States and the former Soviet Union of chemical protection scientists research yan, the results show that: in the presence of pure SF6 gas environment work, skin fu exposed to SF6 gas even for 8 hours, can withstand the highest SF6 gas content of 1000*1 (F6 (1000ppm) at this concentration, not helpful life health and long-term effects. According to this research result, 1000*10-6 is the safety warning line for SF6 gas in SF6 switch room. If the concentration exceeds this level, the monitoring report should start the fan and alarm. SF&fE is a unique gas, has many advantages, is a colorless, tasteless, non-toxic, non-flammable inert gas, and has excellent cooling arc characteristics, special §! ] Is in the open and close equipment arc high temperature under the action of higher ling effect, to avoid local high temperature flammability. SF6 gas is far superior to traditional oil and air. It is used in electrical equipment, can reduce the size of equipment, improve the insulation of oil, air and dry Ada medium. Used in chu electrical equipment, can reduce the size of the equipment, improve the decomposition of the formation of a bowl when toxic, materials and gold bugs for use.

SF6 is a relatively heavy gas, and its stability is 5 times that of air under the same conditions. The relation between pressure and temperature follows the ideal gas law. The critical temperature is the maximum temperature at which SF6 gas can be liquefied. The critical pressure indicates the gas pressure required for liquefaction at this humidity. SF6 can only remain in a gaseous state at temperatures above 45 ° C, and it has the potential to liquefy under normal service conditions, so SF6 cannot be used at low temperatures and too low pressures.

The excellent thermal conductivity of SF6 is one of the reasons for its performance. The good thermal conductivity of SF6 can be attributed to two reasons: first, SF6 has a large molecular weight and a large specific heat, and its convection heat transfer ability is superior to that of air.

Other disadvantages of sf6 gas

SF6 gas toxicity (gas is not pure, containing low sulfur fluoride, hydrogen fluoride and other toxic gases);

Harm to animals (mainly showing fatigue, poor memory, pharynx disease, chest tightness, etc.);

Harm to the environment (a molecule of SF6 gas is 25,000 times that of CO2, and has a long life of about 3400 years, which is not easy to decompose).

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