Numerical analysis of thermal plasma scrubber for CF₄ decomposition

Abstract

CF 4 gas emitted in the semiconductor and display manufacturing process is a very harmful greenhouse gas. It must be removed or converted safely due to its extreme toxicity. Although a CF 4 decomposition system using a thermal plasma scrubber was commercialized, its removal efficiency is limited. In this work, a numerical analysis of CF 4 decomposition in the thermal plasma scrubber was carried out in order to propose an efficient decomposition environment. The decomposition and recombination temperatures of CF 4 were analyzed using thermodynamic equilibrium calculations. The chemical reaction of CF 4 decomposition into carbon and fluorine gas was considered in this numerical analysis. The injection position and angle of the CF 4 were controlled in order to enhance the decomposition rate. The vertical injection of CF 4 near the torch exit improved the mixing of the CF 4 with the thermal plasma flame. In addition, it was confirmed that the high temperature region expanded due to a vortex generated by strong turbulence in the bottleneck-shaped reactor. As a result, it is revealed that the CF 4 injection location and the reactor configuration are the most important factors in improving the decomposition rate.

Characteristic study of decomposing CF4 in a nitrogen microwave plasmas torch at atmospheric pressure

“…As in our previous work about OES diagnosis of N 2 microwave plasma torch, it is found experimentally that the gas temperature and electron density increase with the microwave power [41,42]. The calculation of the thermodynamic equilibrium composition of CF 4 conducted by HSC Chemistry shows that CF 4 is stable up to the gas temperature of 1850 K, begins to decompose at 2000 K and mostly disappears at 3200 K [15][16][17][18]43]. Then, it is evident that the higher plasma temperature generated by APMPT provides a plasma environment suitable for decomposing CF 4 .…”

“…As far as plasma abatement technologies are concerned, there are inductively coupled plasma (ICP) [9][10][11][12], dielectric barrier discharge (DBD) or in combination with catalyst [1], pulsed corona discharge (PCD) [13,14], arc plasma discharge (APD) [15][16][17][18][19][20], surface wave plasma (SWP) [21][22][23][24], and microwave plasma torch (MPT) [25][26][27][28][29][30][31]. To degrade PFCs, some of them are suitable for operating at low pressure, such as ICPs, and the others at atmospheric pressure, such as DBD, PCD, SWP, APD, and MPT.…”

Formation of Products of Incomplete Destruction (PID) from the Thermal Oxidative Decomposition of Perfluorooctanoic Acid (PFOA): Measurement, Modeling, and Reaction Pathways

“…Furthermore, it is evident that, at temperatures above 800 °C, CF 4 is detected in an air bath gas product stream. The formation of CF 4 is of particular concern, as this molecule has notably stable C–F bonds, resulting in reduced propensity of mineralization of PFAS, as it will require temperatures well above 1000 °C for it to be decomposed. , Additionally, CF 4 is recognized as a high GWP greenhouse gas…”

Numerical Simulation of Thermal Flow Characteristics in Plasma Reactor for Rotten Citrus Fruits Drying

“…A commercial computational fluid dynamics (CFD) code, ANSYSfluent (version R.19), was used to analyze the thermal flow characteristics of the plasma [5][6][7][8][9][10]. For turbulence modeling, standard k-ε turbulence modeling was applied.…”