Disintegration of Carbon Dioxide Molecules in a Microwave Plasma Torch.

Hyoung S Kwak,Han S Uhm,Yong C Hong,Eun H Choi

doi:10.1038/srep18436

Hyoung S Kwak, Han S Uhm + Show 2 more

Open Access

https://doi.org/10.1038/srep18436

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Abstract

A pure carbon dioxide torch is generated by making use of 2.45 GHz microwave. Carbon dioxide gas becomes the working gas and produces a stable carbon dioxide torch. The torch volume is almost linearly proportional to the microwave power. Temperature of the torch flame is measured by making use of optical spectroscopy and thermocouple. Two distinctive regions are exhibited, a bright, whitish region of high-temperature zone and a bluish, dimmer region of relatively low-temperature zone. Study of carbon dioxide disintegration and gas temperature effects on the molecular fraction characteristics in the carbon dioxide plasma of a microwave plasma torch under atmospheric pressure is carried out. An analytical investigation of carbon dioxide disintegration indicates that substantial fraction of carbon dioxide molecules disintegrate and form other compounds in the torch. For example, the normalized particle densities at center of plasma are given by nCO2/nN = 6.12 × 10−3, nCO/nN = 0.13, nC/nN = 0.24, nO/nN = 0.61, nC2/nN = 8.32 × 10−7, nO2/nN = 5.39 × 10−5, where nCO2, nCO, nC, nO, nC2, and nO2 are carbon dioxide, carbon monoxide, carbon and oxygen atom, carbon and oxygen molecule densities, respectively. nN is the neutral particle density. Emission profiles of the oxygen and carbon atom radicals and the carbon monoxide molecules confirm the theoretical predictions of carbon dioxide disintegration in the torch.

Highlights

One of the most difficult problems in mankind is the global warming phenomenon, caused by an increase in the carbon dioxide concentration in the atmosphere
The bright, whitish region is a typical torch based on plasma species and the bluish, dimmer region is carbon monoxide (CO) recombining with oxygen
The Gibbs free energy of the spontaneous disintegration is given by G = ∆H − T∆S; the disintegration temperature of the carbon dioxide molecules into carbon monoxide and oxygen atoms is calculated to be about T = ∆H/∆S = 3600K

Summary

Introduction

One of the most difficult problems in mankind is the global warming phenomenon, caused by an increase in the carbon dioxide concentration in the atmosphere. Carbon dioxide was dissociated by recently laser beams[15] at room temperature, but laser energy needed for a substantial amount of CO2 dissociation is very high. The dissociation of carbon dioxide molecules at a high temperature produces oxygen atoms abundantly, which are very reactive. The typical energy efficiency of ICP into the plasma is less than 50% and drops markedly at high power (> 100 kW)[25] For these reasons, the best solution would be to generate a pure carbon dioxide torch operated by microwaves without electrodes. The carbon dioxide torch exhibits two distinctive regions: a bright, whitish region of a high-temperature zone and www.nature.com/scientificreports/. The bright, whitish region is a typical torch based on plasma species and the bluish, dimmer region is carbon monoxide (CO) recombining with oxygen

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