Optical Emission Spectroscopy Diagnostics of Atmospheric Pressure Radio Frequency Ar-H₂ Inductively Coupled Thermal Plasma

Analysis of Essential Features and Optimal Operational Parameters of an RF-ICP Torch for Waste Treatment Applications

“…When these argon atoms exist in either the excited state Ar* or the higher excited state Ar**, their return to a metastable state or resonance energy level results in the emission of light. This sequence of events is mathematically represented by the following equations [55]:…”

“…By plotting the left-hand side of Equation (5) [ln I ki λ ki A ki g k ] on the vertical axis and E k on the horizontal axis, the T eff can be derived from the inverse of the slope of the linear fitted line. The Boltzmann plot is an efficient method for determining T eff in atmospheric plasma torches since it does not require a standard source for calibration, and the accuracy increases with the energy range of the emitted lines used in the calculations [54][55][56]. All lines in Table 1 are well isolated and unabsorbed and were chosen to implement the Boltzmann plot.…”

“…Additionally, applying probe measurements to atmospheric pressure plasmas faces challenges related to significant heat load and high-frequency noise [53,54]. Consequently, optical methods that rely on spectral line emission intensity are frequently employed as an alternative to probe measurements for determining internal plasma parameters (T eff and n e ) within the atmospheric pressure range plasma [55][56][57][58][59].…”

“…The electron temperature of rf inductive Ar plasmas at atmospheric pressure was determined by analyzing the line intensity ratio of the visible spectrum using the Boltzmann plot method. This approach assumes that the plasma is in a local thermodynamic equilibrium (LTE) condition [55][56][57][58][59]. Through spectroscopic analysis of the widening of spectral lines caused by the presence of electric fields in the plasma, Stark broadening is a technique used to detect the electron density in a plasma [60].…”

Optical Characterization of RF Plasma Torch for Municipal Solid Waste (MSW) Treatment Process

“…Plasma temperature (Te), species density, plasma composition, and ionization state can be calculated and determined from the OES measurements. Numerous studies using the OES method to examine the plasma jet's characteristics have recently been conducted [18][19][20][21]. Despite significant research and advancements in this field, a more profound comprehension of a plasma jet's characteristics is still required.…”