Theoretical study by density functional theory calculations of decomposition processes and primary products of C₅F₁₀O with moisture content

Abstract

C5F10O has been widely studied as a great potential alternative gas to SF6, a most potent industrial greenhouse gas that is predominantly used as an insulating medium in electrical equipment, due to its excellent insulation properties and environmental characteristics. Several experimental and theoretical attempts have been made and have obtained valuable results in the last five years. However, few researchers have thoroughly investigated the decomposition mechanism and the main decomposition pathways of the C5F10O/H2O system, which are important for evaluating the insulating and environmental performance and providing guidance for engineering application. Herein, the decomposition characteristics and mechanism of C5F10O in the presence of moisture content was studied by density functional theory calculations. The main types of decomposition products with relatively high content have been summarized based on the evaluation of cleavage reactions and the influence of moisture. The electrical, environmental and safety performances of the primary products were analyzed. CF3CFCF3, CF3CO, CF3, OH and H radicals are the most primary particles formed by dissociation of C5F10O and H2O. These particles may further convert into more than 20 kinds of relatively stable products, among which C4F10, C3F8, C6F14, C3HF7, C2F6 and CO are primary ones. In addition, COF2, CO2, CO and C3F6 can be used as components for estimating the degree of failures. The existence of H2O has a negative impact on the insulation and environmental performance. In particular, trace water has a direct contribution to the production of highly toxic COF2, CO and HF. Thus, it is necessary to strictly control the moisture and develop application standards before any industrial application of C5F10O in electrical equipment.

High anisotropic magnetoresistance, perfect spin-filtering effect, and negative differential resistance effect of Cr-doped anatase phase TiO2

“…Then the formation energy under O-rich condition results show that the Cr-doped system is thermodynamically stable, and device Cr_Type-b has the strongest electronic transfer capacity under zero bias among all half-metal devices. On the basis of density functional theory (DFT) [38][39][40] and nonequilibrium Grimm function (NEGF) [41][42][43], we construct devices along the y and z directions of the Cr-doped system respectively, and study their transport properties. The calculated results display that the Cr-doped system has close to 300% AMR in different transport directions, perfect spin filtering efficiency, and NDR effect.…”

Theoretical study of the discharge decomposition mechanism of environment-friendly insulation gas HFO-1234ze(E) in the presence of trace water

“…The larger the molecular orbital gap value is, the higher the chemical stability is [1]. The calculations of ionization energy (IE), electron affinity (EA) and molecular orbital energy gap (E G ) are expressed as the following expressions [10]. ( ) ( )…”

“…Although their ionization energies are relatively high, it can be found that both CF 3 H and CF 3 OH are less electronegative than HFO-1234ze(E) by comparing the electron affinity. CF 3 H is a greenhouse gas with a GWP value of 11,700 times that of CO 2 [10].…”

Theoretical study of the decomposition mechanism of a novel eco-friendly insulation medium HFO-1336mzz(E) considering the effect of trace humidity

“…At present, several potential environmentally friendly alternative gases to SF 6 mainly include Novec 4710 (C 4 F 7 N), Novec 5110 (C 5 F 10 O) and HFO-1336mzz(E), which has been attracted considerable attention. Recently, a great deal of research has been carried out on C 4 F 7 N [9][10][11] and C 5 F 10 O [12][13][14], such as insulation properties, decomposition properties, and gas-solid compatibility, etc. In contrast, the properties of HFO-1336mzz(E) have been less studied.…”