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ABSTRACT
In this work, the direction of allothermal coal pyrolysis reaction was driven by the waste heat of blast furnace slag. The structure features of the coal char mixed with/without slag was characterized by BET and SEM. The experiments of thermogravimetric analyzer were conducted to obtain the coal pyrolysis characteristics. The kinetic parameters of coal pyrolysis reaction were extracted using the reaction model based on the Arrhenius law and Li Chung-Hsiung method. The BET and SEM results showed that the slag addition could improve the structure features of the coal char effectively. The specific surface area, pore volume & size increased significantly. With the slag addition, characteristic temperatures of pyrolysis reaction did not change obviously. Peak temperature and final temperature increased by approximate 3.38 K and 5.55 K, respectively. However, the maximum weight reduce and pyrolysis characteristic index were enhanced dramatically. A single three-order reaction model was used to deduce the coal pyrolysis reaction successfully. The activation energy of the coal pyrolysis reaction decreased from 116.31 kJ·mol−1 to 90.67 kJ·mol−1, and the pre-exponential factor decreased from 6606.19 min−1 to 2457.91 min−1. Overall, slag provided the heat for the pyrolysis reaction and acted as the catalyst.
Nomenclature
| (dW/dt)max | = | Maximum weight reduce rate, %·min−1 |
| ΔWmax | = | Maximum weight reduce, % |
| Ts | = | Initial temperature, K |
| Tf | = | Final temperature, K |
| Tp | = | Peak temperature, K |
| P | = | Characteristic index of coal pyrolysis, %3·(min2·K2)−1 |
| T | = | Absolute temperature, K |
| A | = | Pre-exponential factor, min−1 |
| β | = | Heating rate, K·min−1 |
| E | = | Activation energy, kJ·mol−1 |
| R | = | Universal constant, kJ·mol−1·K |
| α | = | Percentage of weight reduce, % |
| m0 | = | Initial weight, mg |
| mt | = | Real-time weight, mg |
| m∞ | = | Final weight, mg |
| n | = | Reaction order of the coal pyrolysis reaction |
| R2 | = | Correlation coefficient of the straight line. |
Abbreviations
| BFS | = | Blast Furnace Slag |
| FX coal | = | Fuxin Coal |
| BET | = | Brunauer Emmett Teller |
| BJH | = | Barrett Joyner Halenda |
| SEM | = | Scanning Electron Microscopy |
Acknowledgments
This research was supposed by The National Natural Science Foundation of China (51704071), The National Postdoctoral Program for Innovative Talents (BX201600028), The Fundamental Research Funds for the Central Universities (N170204016). We would very appreciate the reviewers’ constructive comment on the manuscript.