Search Results (2)

Perfluoroisobutyronitrile (C₄F₇N), an environment-friendly insulating gas, has excellent insulating properties and has the potential to be used in gas-insulated equipment when mixed with CO₂. Selecting suitable adsorption materials to adsorb the decomposition products of the C₄F₇N mixture can ensure the safe and stable operation of the gas-insulated equipment and the personal safety of the operators in the electric power industry. The adsorption characteristics of the ZSM-5 molecular sieve on C₄F₇N and its five fluorocarbon decomposition products were investigated by adsorption experiments. The results show that the ZSM-5 molecular sieve has a certain adsorption effect on six fluorocarbon gases; the adsorption performance of C₃F₆ and C₃F₈ are the best, with an adsorption efficiency over 85%, while the concentration of CO₂ and C₄F₇N is affected by the ZSM-5 molecular sieve. At the same time, the paper based on the Metropolis Monte Carlo simulation of Materials Studio software found that the ZSM-5 molecular sieve has the strongest adsorption effect on C₄F₇N molecules and the weakest adsorption effect on CO₂ molecules. The stronger the polarity of the gas molecule, the more obvious the adsorption effect of molecular sieve structure on it. As a result, the ZSM-5 molecular sieve could be used in tail gas purification of insulated equipment, as well as to provide solutions for the development and production of protective equipment. Full article

An environment-friendly insulating gas, perfluoroisobutyronitrile (C₄F₇N), has been developed recent years. Due to its relatively high liquefaction temperature (around −4.7 °C), buffer gases, such as CO₂ and N₂, are usually mixed with C₄F₇N to increase the pressure of the filled insulating medium. During these processes, the insulating gases may be contaminated with micro-water, and the mixture of H₂O with C₄F₇N could produce HF under breakdown voltage condition, which is harmful to the gas insulated electricity transfer equipment. Therefore, removal of H₂O and HF in situ from the gas insulated electricity transfer equipment is significant to its operation security. The adsorbents with the ability to remove H₂O but without obvious C₄F₇N/CO₂ adsorption capacity are essential to be used in this system. In this work, a series of industrial adsorbents and desiccants were tested for their compatibility with C₄F₇N/CO₂. Pulse adsorption tests were conducted to evaluate the adsorption performance of these adsorbents and desiccants on C₄F₇N and CO₂. The 5A molecular sieve showed high adsorption of C₄F₇N (22.82 mL/g) and CO₂ (43.86 mL/g); F-03 did not show adsorption capacity with C₄F₇N, however, it adsorbed CO₂ (26.2 mL/g) clearly. Some other HF adsorbents, including NaF, CaF₂, MgF₂, Al(OH)₃, and some desiccants including CaCl₂, Na₂SO₄, MgSO₄ were tested for their compatibility with C₄F₇N and CO₂, and they showed negligible adsorption capacity on C₄F₇N and CO₂. The results suggested that these adsorbents used in the gas insulated electricity transfer equipment filled with SF₆ (mainly 5A and F-03 molecular sieves) are not suitable anymore. The results of this work suggest that it is a good strategy to use a mixture of desiccants and HF adsorbents as new adsorbents in the equipment filled with C₄F₇N/CO₂. Full article