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The supply and applications of C4F7N

2020-08-05 14:13

Beijing Yuji is one of the manufacturers of fluorine-containing chemicals, which has the production and purification technology of 2,3,3,3-tetrafluoro-2-(trifluoromethyl)propanenitrile.

For a phase-out of SF6 from electrical power equipment, a replacement gas with acceptable environmental impact would be beneficial. 2,3,3,3-tetrafluoro-2-(trifluoromethyl)propanenitrile is a sustainable alternative insulating gas to sulfur hexafluoride (SF6) for electrical equipment insulation. To meet this product demand of the power industry, Yuji develops the production process of 2,3,3,3-tetrafluoro-2-(trifluoromethyl)propanenitrile and realize its mass production supply.

2,3,3,3-tetrafluoro-2-(trifluoromethyl)propanenitrile, also named as Heptafluoroisobutyronitrile, is an eco-friendly electrical insulation gas and an alternative insulating gas to SF6. It has excellent dielectric properties for medium and high voltage applications, a wide range of operating temperatures. At the same time, it is non-flammable and non-ozone depleting. C4F7N also has many other advantages when it is used as an insulation gas. It is low toxicity and it obtains better compatibility with other materials in the switchgears or equipment. Pure heptafluoroisobutyronitrile has a relative dielectric strength two times greater than SF6 at a given pressure. It can be used in a variety of gas mixtures.

The key performance comparison of C4F7N and SF6

Properties(77℉) C4F7N SF6
Molecular weight(g/mol) 195 146
Flash point(℉) None None
Boiling point @14.5 psia(℉) 23.5 -90.9
Freezing point(℉) -180 -59.3(@32.9 psia)
Gas density @14.5 psia(lb/ft3 0.49 0.37
Dielectric strength @14.5 psia(kV) 27.5 14
Vapor pressure(psia) 36.5 312
Atmospheric lifetime(years) 30 3200
GWP100 years(CO2=1) 2100 23500
ODP(CFC-11=1) 0 0

2,3,3,3-tetrafluoro-2-(trifluoromethyl)propanenitrile, as an Insulating Gas, is well-suited as an alternative to SF6 in insulating and arc quenching gas mixtures for medium and high voltage applications.

Alstom applied one patent “Gas-insulated medium or high-voltage electrical apparatus including heptafluoroisobutyronitrile and tetrafluoromethane”. This invention relates to a medium- or high-voltage electrical apparatus which includes a sealed enclosure containing electrical components and a gas mixture providing electrical insulation and/or the extinction of electric arcs that may occur inside said enclosure, the gas mixture including heptafluoroisobutyronitrile and tetrafluoromethane.

General Electric (GE) has applied one patent “Method and facility for filling a gas-insulated electrical apparatus comprising a mixture of heptafluoroisobutyronitrile and carbon dioxide”. This patent relates to a method and a facility for filling a high- or medium-voltage gas-insulated electrical apparatus in which the insulating gas comprises a mixture of heptafluoroisobutyronitrile ((CF3)2CFCN) and carbon dioxide. Said method and said facility using a mixture of (CF3)2CFCN and CO2 in pressurized liquid form which is heated to a temperature no lower than the critical temperature of the mixture.

GE developed the g3 gas mixture which is based on heptafluoroisobutyronitrile with a balance percentage of CO2. G3 gas offers a low global warming potential (GWP) and excellent dielectric properties. It fits with applications whose temperatures are down to -30℃. In the meantime, it is stable versus temperature and time.