Abstract
CO2 conversion by plasma technology is gaining increasing interest. We present a carbon (charcoal) bed placed after a Gliding Arc Plasmatron (GAP) reactor, to enhance the CO2 conversion, promote O/Ov removal and increase the CO fraction in the exhaust mixture. By means of an innovative (silo) system, the carbon is constantly supplied, to avoid carbon depletion upon reaction with O/O-2. Using this carbon bed, the CO2 conversion is enhanced by almost a factor of two (from 7.6 to 12.6%), while the CO concentration even increases by a factor of three (from 7.2 to 21.9%), and O-2 is completely removed from the exhaust mixture. Moreover, the energy efficiency of the conversion process drastically increases from 27.9 to 45.4%, and the energy cost significantly drops from 41.9 to 25.4 kJ.L-1. We also present the temperature as a function of distance from the reactor outlet, as well as the CO2, CO and O-2 concentrations and the temperature in the carbon bed as a function of time, which is important for understanding the underlying mechanisms. Indeed, these time-resolved measurements reveal that the initial enhancements in CO2 conversion and in CO concentration are not maintained in our current setup. Therefore, we present a model to study the gasification of carbon with different feed gases (i.e., O-2, CO and CO2 separately), from which we can conclude that the oxygen coverage at the surface plays a key role in determining the product composition and the rate of carbon consumption. Indeed, our model insights indicate that the drop in CO2 conversion and in CO concentration after a few minutes is attributed to deactivation of the carbon bed, due to rapid formation of oxygen complexes at the surface.
Original language | English |
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Article number | 136268 |
Number of pages | 16 |
Journal | Chemical Engineering Journal |
Volume | 442 |
DOIs | |
Publication status | Published - 15 Aug 2022 |
Keywords
- CO2 conversion
- Gliding arc plasma
- Carbon bed
- Oxygen removal
- Gas separation
- CO enrichment
- BARRIER DISCHARGE PLASMA
- TEMPERATURE OXIDATION
- BOUDOUARD REACTION
- OXY-COMBUSTION
- DIOXIDE
- GASIFICATION
- SURFACE
- GAS
- CONDUCTIVITY
- SIMULATION