The intrinsic reactivity of coal char conversion compared under different conditions of O2/CO2, O2/H2O and air atmospheres
| Autor: | Gong Yusen, Kang Bie, Tianyao Xu, Peifang Fu, Yang Liu |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Reaction mechanism
business.industry Chemistry 020209 energy 02 engineering and technology Activation energy Reaction rate 020401 chemical engineering Chemical engineering Chemisorption Desorption 0202 electrical engineering electronic engineering information engineering Coal Reactivity (chemistry) Char 0204 chemical engineering business |
| Zdroj: | Journal of the Energy Institute. 93:1883-1891 |
| ISSN: | 1743-9671 |
| Popis: | The reasons for the intrinsic reactivity differences in coal char conversion under an O2/H2O atmosphere compared with that under an O2/CO2 or O2/N2 atmosphere have been investigated in a thermogravimetric analyzer by a simple variable activation energy (SVAE) method combined with an adsorption/desorption reaction mechanism. The results show that only CO2 or H2O chemisorption occurred in the non-isothermal experiments, not gasification; however, the intrinsic reaction rate (IRR) of coal char conversion at the same O2 concentration still increases in an orderly manner under O2/CO2, O2/N2 and O2/H2O atmospheres. This result is due to the different chemisorption mechanisms of CO2 and H2O, namely, the production of C(CO), C(OH) and C(H) from CO2 and H2O chemisorption. At the same O2 concentration, the trends and magnitudes of variable activation energies for coal char combustion under O2/CO2 and O2/N2 atmospheres are similar, while they are very different from those under O2/H2O conditions. Therefore, CO2 has little influence on the reactivity, while H2O changes the reactivity. In addition, according to the developed reaction mechanism, it is concluded that the SVAE method contributes to the characteristic intrinsic reactivity of coal char conversion under different atmospheres. |
| Databáze: | OpenAIRE |
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