Experimental Study of C4F7N and its Decomposed Products Adsorption on Gamma-Aluminum Oxide

Replacing SF
6
in gas insulated high-voltage equipment is now a hot topic, and Heptafluoroisobutyronitrile (C
3
F
7
CN) has received extensive attention because of its excellent insulation performance and low GWP value. Whether activated alumina (γ-AI
2
O
3
), a common adsorbent in traditional SF
6
based equipment, can be applied in C
3
F
7
CN based equipment, need to be discussed. In this work, the discharge experiment of C
4
F
7
N/N
2
was carried out, and the result shows that the decomposition products mainly contained several fluorocarbon and fluorocarbon nitrogen, such as CF
3
CN, C
2
F
5
CN, CF
4
, C
2
F
6
, C
3
F
8
, C
2
F
4
, C
3
F
6
. Then, gas samples were collected after different times of discharge, and the gas adsorption experiments of these compounds by γ-AI
2
O
3
was analyzed and calibrated by gas chromatography. The results show that the C
3
F
7
CN and its decomposed products which contain C=N exhibits obvious adsorption behavior, and γ-AI
2
O
3
can be used for adsorbent toward compounds containing cyano-group in environmental insulation equipment using C
3
F
7
CN as medium.