Biomass resources in China are widely distributed and highly abundant, holding great potential for substituting traditional fossil fuels and promoting the achievement of carbon peak and carbon neutrality goals. During storage and transportation, biomass is prone to self-heating. When the accumulated heat raises the internal temperature of biomass to a certain level, chemical reactions will gradually accelerate, leading to biomass self-ignition. In traditional biomass self-ignition studies, thermogravimetric/calorimetric experiments typically employ powdered samples. However, this approach significantly deviates from the actual storage conditions of biomass. Moreover, existing biomass reaction kinetics models exhibit poor adaptability below 250 ℃. To address these issues, a testing platform for the low-temperature pyrolysis and oxidation characteristics of biomass was established. The thermal degradation behavior of rice straw and soybean shell samples with different particle sizes (original large particles, 2.0 mm particles, and 0.2 mm particles) was investigated under various oxygen concentrations. Two kinetic models, namely the pyrolysis-independent component oxidation model and the pyrolysis-lumped oxidation model, were developed and optimized. These models accurately predicted the pyrolysis and oxidation behavior of biomass in the low-temperature range. The results indicated that the reaction rate increased significantly with temperature. However, as biomass consumption progressed, the promoting effect of temperature on the reaction rate gradually diminished. Increasing the oxygen concentration also accelerated the reaction rate, but its impact was weaker than that of temperature elevation. Under the same temperature and oxygen concentration conditions, the 2.0 mm particle samples exhibited the highest reaction rate, while the original samples had the lowest rate, with the 0.2 mm particle samples falling in between. Experiments on biomass samples with original particle sizes and the development of targeted kinetic models are more representative of real-world conditions. The pyrolysis-lumped oxidation model effectively predicted the mass loss behavior of rice straw and soybean shell samples with different particle sizes under various oxygen concentrations as the temperature increased, demonstrating its applicability for predicting low-temperature pyrolysis and oxidation reactions of biomass.
| 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 |