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SF6 Gas An Introduction of SF6 Gas

Some Typical Properties of SF6 Gas

  • The Chemical Formula: – SF6.
  • The Molecular Weight:- 146.05 g/mol.
  • The gas is a colorless non-flammable gas.
  • This gas is also nontoxic.
  • This gas is five times heavier than air.
  • The dielectric strength of SF6 is three times higher that of air.
  • It has very good arc quenching property.
  • The gas has very good heat absorbing capability.

This last property of the gas makes it very effective greenhouse gas. 1 kg of SF6 gas has the greenhouse effect as same as of 23,900kg CO2. For this reason, we should take special care during handling this gas. Also, we should not release the gas in the atmosphere knowingly and unknowingly.

The pressurized SF6 gas has more dielectric strength than a nonpressurized SF6 gas. By increasing pressure of SF6 gas up to 8 bar, we can reduce the size of the electrical system up to 20 times than an equivalent conventional air-insulated electrical system. Also, the pressure increases the arc quenching property of the SF6 gas.

SF6 gas molecule has one sulfur atom at the center, and six numbers of fluorine atoms surround the central sulfur atom symmetrically. The bonds between sulfur and fluorine in SF6 molecules are stable ionic bonds.

sulfur hexafluoride sf6
Structure of SF6

The solubility of SF6 gas in water is 4 times lower than that of air.

Green House Effect of SF6 Gas

The heat energy comes to the earth surface through electromagnetic radiation from the sun. After reaching on the earth surface, a significant portion of the heat reflects back to space.

The gases and flying particles in the atmosphere absorb some portion of the heat. Hence, they prevent the heat to reflect back entirely to space.

This makes the earth warmer. The balance condition of the incident sun heat, the reflection of the heat from the earth surface and absorption of the heat by atmosphere maintain the temperature of this planet where life can grow.
If this balance breaks up, the climate of the planet continues to change, which may affect the lives on the earth. The greenhouse gases are those gases in the atmosphere, which have the capability of absorbing the heat to prevent clear reflection of heat to the space from earth.

The carbon dioxide (CO2) is the most effective greenhouse gas. Because the presence of CO2 is quite large in the atmosphere. Also, the SF6 gas is a very effective greenhouse gas. But its actual effect in global warming is still negligible compared to CO2. Since the volume of SF6 gas is quite less in the atmosphere compared to CO2 and other greenhouse gases.

Global Warming Index of SF6

Although it is true the global warming index of SF6 is 23,800. That means, 1 kg of SF6 gas can contribute the same greenhouse effect which can be contributed by 23,800kg of CO2.

The SF6 gas is very stable gas. Nearly no agent presents in the atmosphere can reduce the SF6. The life span of SF6 is about 3000 years. Because of its property of high effectiveness of greenhouse and due to its tremendous stability we always highly restrict the release of SF6 gas in the atmosphere.

Applications or Uses of SF6 Gas

There are many gases available which have either very good in insulating property or arc quenching property. But both properties are good only in SF6 gas. For this reason; still, we could not find any alternative of this gas for using in the high, very high and ultra-high electrical system.

Also, there are many nonelectrical uses of SF6 gas. Such as, we use the gas in metallurgy, electronics, scientific equipment, ocular surgery, and military applications, etc.

Transportation of SF6 Gas

The critical temperature of this gas is 45.54 °C
The critical pressure of that gas is 3.759 Mpa.
Hence, the gas can be liquefied by compressing in the cylinder. The SF6 gas is transported in its compressed liquefied form in the strong metallic cylinders.

Electronegativity of SF6 Gas

The SF6 molecules are highly electronegative. That means the molecules can highly absorb free electrons.

As the SF6 gas is very stable gas and also it is very low soluble in water, the presence of this gas does not affect the life cycle, on land as well as in water. But as it does not have oxygen and it is heavier than air, the accumulation of SF6 on the land surface causes suffocation to the living beings.

This is to remember that the SF6 gas does not have any ozone depletion potential. So, it does not have any impact in the ozone layer.

At last, we want to tell that this gas is not natural gas. Rather it is an artificial gas and only produced in SF6 gas manufacturing industries.

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