In order to understand the properties of char which is the main byproduct of coal pyrolysis in the reactor with internals, especially the char prepared at high temperatures, the char samples were prepared by pyrolysis of Yulin bituminous coal under vacuum condition between 1 000 ℃ and 1 500 ℃ in the fixed-bed reactor with internals. The variations of pore structure, composition, calorific value, and carbon structure of chars with pyrolysis temperature were studied. The isothermal combustion characteristic and kinetics were investigated by MFBRA(micro fluidized bed reaction analyzer). The results show that the increase in pyrolysis temperature leads to a deeper degree of pyrolysis. As the pyrolysis temperature increases, the C content and C/H molar ratio of chars gradually increase, H and O contents of chars gradually decreases, and the calorific value increases slightly. The specific surface area and pore volume of chars firstly decrease with the increase of pyrolysis temperature, and then remain essentially constant after the pyrolysis temperature exceeds 1 300 ℃, which is consistent with the trend of graphitization degree. The three-dimensional diffusion model G(x)=[1-(1-x)1/2]2 can well describe the combustion process of chars. The activation energy and pre-exponential factor increase with the increase of pyrolysis temperature, and vary in the range of 30.49~90.17 kJ/mol and 0.69~352.25 s-1, respectively. The significant decrease in combustion reactivity of char prepared above 1400 ℃ is mainly due to the sharp increase of C/H.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |