Scalable Microwave Plasma Sources From Low to Atmospheric Pressure

Abstract

There are very specific demands on the plasma processes used in various plasma technological applications. Microwave plasmas offer a wide range of applications for different pressures ranging from very low pressure (<0.1 Pa) over low pressure (0.1‐100 Pa) and medium pressure (103‐104 Pa) up to atmospheric pressure (105 Pa). This contribution is a short review on some microwave based plasma sources at different pressure ranges and a brief introduction into the plasma physics behind them (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Trendbericht Technische Chemie 2021

“…27) einen Druckbereich von 0,1 bis 1000 mbar abdecken können. 29) Der aktuelle Trend geht dahin, mikrowellenangeregte Plasmen zwischen 100 und 1000 mbar einzusetzen oder dielelektrisch behinderte Entladungen (DBD), welche einfach skalierbar sind. Plasmen sind generell schnell ein-und abschaltbar und daher ideal für den Betrieb mit regenerativen Energien.…”

Microwave plasma emerging technologies for chemical processes

“…Some of the limitations that have hindered widespread implementation of MWP at industrial scale include the cost of equipment, challenges related to process scalability, controllability and stability as well as the cost of electric power. For further information on theoretical concepts related to MWP, the reader is referred to the literature …”

On the improvement of chemical conversion in a surface-wave microwave plasma reactor for CO 2 reduction with hydrogen (The Reverse Water-Gas Shift reaction)

“…In this regard, plasma-assisted reactors are key players in the development of electricity-based technologies. Microwave plasma (MWP) is considered one of the most promising alternatives due to various benefits that have been widely discussed in the literature [13][14][15][16][17]. Particularly, travelling-wavesustained discharges are investigated because of the flexible operation regimes (continuous wave and pulse), the broad attainable pressure range (10 -5 torr -1 atm) and wave-frequency range (f = 500 kHz -10 GHz), as well as wide plasma reactor size range in cylindrical reactor configurations (R = 0.5 mm -15 cm) [18].…”

“…Hence, the variation of the E field largely influences the plasma parameters, as wave properties, electron density (n e ), and electron temperature (T e ) are self-consistently related to each other[30].Electron density: In the process of wave-to-plasma power coupling, the wave energy flux and the electron density decay along the discharge. As the wave propagates, a fraction of the wave energy is absorbed by the plasma column for its sustenance as far as the condition n e ≥ n cr is maintained; the critical plasma density at 2.45 GHz is n cr = 7.5•10 16 [1/m 3 ][15].Fig. 5(b)…”