Characteristic study of decomposing CF 4 in a nitrogen microwave plasmas torch at atmospheric pressure

Self Cite

An atmospheric-pressure microwave plasma torch (APMPT) is employed to drive Boudouard reaction [C(s)+CO2(g) 2CO(g)] to convert CO2 into CO with storable chemical energy, which is available from the renewable electric energy, such as wind and solar power. In this experiment, the solid carbon is placed in the downstream of the afterglow of CO2 plasma produced by APMPT, which is enclosed in reaction chamber, thereby the reaction occurs in the environment with a plenty of the active species and the large enthalpy. The conversion rate and energy efficiency are experimentally determined by measuring the change of the gas composition, which is analyzed with a Fourier transformation infrared spectrometer (FTIR) and Gas Chromatograph (GC). The variations of conversion rate and energy efficiency are investigated with respect to the plasma state, which is tuned by changing microwave power, gas flow rate, and argon-to-CO2 mixture ratio, and the different forms of carbon material. Furthermore, the high conversion efficiency is obtained with use of the herbaceous type of biomass as carbon material and by increasing microwave power, however, the large percentage of CO2 in carrier gas and increasing gas flow rate impose a negative influence on CO2 conversion.

Section: Co 2 Conversion In Br Driven By Microwave Plasma Torchmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of CO₂ conversion in Boudouard reaction driven by an atmospheric-pressure microwave plasma torch

Wu¹,

Li²,

Niu³

et al. 2023

Self Cite

“…Plasma-based abatement techniques have received significant attention in recent years because the regulations and penalties for carbon emissions are likely to be strengthened [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. As plasma sources consume electricity compared to combustion, which produces CO 2 directly, theoretically, the entire conversion process becomes carbon-neutral when all the electricity needed is supplied from renewable energy sources such as solar and wind power [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…As plasma sources consume electricity compared to combustion, which produces CO 2 directly, theoretically, the entire conversion process becomes carbon-neutral when all the electricity needed is supplied from renewable energy sources such as solar and wind power [17,18]. Various thermal plasmas have been used to decompose VOCs [3][4][5][6][7] and PFCs [8][9][10][11][12][13][14][15][16]. Specifically, for PFC decomposition, direct current (DC) arc plasmas, gliding arc discharges, and microwave plasmas displayed destruction/removal efficiencies (DREs) of 99.6% [9][10][11], 97.5% [12,13], and 98.4% [14][15][16], respectively.…”

Section: Introductionmentioning

confidence: 99%

Machine learning-based prediction of operation conditions from plasma plume images of atmospheric-pressure plasma reactors

Bong

Kim

Ali

et al. 2023

A technique was proposed in this paper to monitor the key operating conditions of a plasma abatement system, which are the concentration of the carbon-containing process gas and the treatment flowrate, from a plasma plume image acquired using an inexpensive color camera. The technique is based on the observation that the shape and color of the plasma plume vary with the variations in the specific energy input and plasma gas composition. In addition, because these variations are marginal and it is challenging to identify an analytical relationship between these variations and the operating conditions, the prediction model is obtained in a data-driven manner. Specifically, the model was composed of a set of convolutional autoencoders (CAEs) and a dense neural network. Furthermore, it was trained only with images captured under normal operation so that 1) images captured under abnormal operations could be identified based on the reconstruction error of the trained CAEs and 2) predictions are made only on normal images. As a demonstration, methane was tested as a process gas, and oxygen was used as a reaction agent in a nitrogen-rich environment. The test results showed that the optimized model could predict the treatment flowrate and process gas concentration with 96% probability within ±3.08 slpm and ±300 ppm, respectively.

“…Moreover, since MW plasma is stricken by MW radiation without the use of electrodes, the technical issues caused by the lifetime of the electrode met in chemical applications are completely settled. In addition, as no vacuum system is needed, operation at atmospheric pressure could bring about some merits in industrial applications, such as reducing investment and maintenance costs and avoiding erosion to vacuum systems [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen production by microwave plasma decomposition of H₂S at atmospheric pressure with cooling implemented in its afterglow

Xie

Niu

et al. 2023

Self Cite

In this work, H2S is decomposed with use of an N2 microwave plasma torch at atmospheric pressure with the hydrogen as the main product as well as sulfur. The variation of conversion rate of H2S into hydrogen is investigated with respect to various dilution ratios of H2S in N2 carrier gas, microwave power, total flow rate, and arrangement of cooling rod in reaction chamber. And it is experimentally found that the direct cooling of the afterglow by introducing a cooled cylinder opposite to it downstream in reaction chamber takes effect in enhancement of the conversion rate of H2S to H2 and there exists an optimum for each conversion curve, which is dependent of the microwave power, gas flow rate, the relative distance of cooling rod in afterglow.