Abstract
It is easier to optimize reactions when the mechanism is well understood. Nowadays, catalytic carbon gasification is an area of industrial importance. The mechanism based on C-bulk diffusion has been recently updated. The relevance of the Tammann temperature to get efficient carbon/catalyst nanoparticle contact is now better understood. However, the interaction between kinetics and thermodynamics still needs some clarification. Rate jump is a kinetic phenomenon observed in some cases in catalytic carbon gasification by air or oxygen following a minor increase in temperature (v.g. ΔT = 5 °C). This occurrence has been reported, but the phenomenon is not well understood. In this short review, we show that the rate jumps can be consistently explained by the “carbon-worm” mechanism due to a jump in the temperature of the moving nanocatalyst particles. The carbon bulk diffusion step is then much faster and the external film mass transfer becomes the rate-limiting step. The reaction order changes from zero to one. The nature and role of catalyst‑carbon contact in catalytic carbon gasification is discussed.
Original language | English |
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Pages (from-to) | 313-318 |
Number of pages | 6 |
Journal | Fuel Processing Technology |
Volume | 179 |
DOIs | |
Publication status | Published - 1 Oct 2018 |
Keywords
- Carbon gasification
- Catalyst role
- Mechanism
- Rate jumps