振动热压脱水过程中褐煤孔结构变化规律研究

Pore Structure Variation Law of Lignite During Vibrating Hot- Pressing Dehydration

研究了褐煤振动机械热压脱水过程中,温度、机械压力、振动力作用下褐煤孔隙率、孔径分布、平均孔径与比表面积的变化规律。结果表明,温度、压力、振动力的升高均能有效降低褐煤的孔隙率,但褐煤对振动力存在响应范围。随着温度和压力的升高,褐煤失去水分后孔会发生坍塌并演变成较小尺寸的孔,导致颗粒间孔与大孔显著降低,而中孔略有增加;振动力可使颗粒间排列更紧密,破坏褐煤颗粒结构,改变褐煤孔径分布。褐煤平均孔径随温度和机械压力的升高大幅降低,比表面积先略有降低,在100℃和5MPa之后又略有增加,振动力对褐煤平均孔径和比表面积的影响较小。

Based on vibrating hot - pressing dehydration experiments, the effects of temperature, pressure and vibration force on the pore structure variation of lignite were studied. The results show that, porosity of lignite decreases with the increase of temperature, pressure and vibration force. The increase of vibration force in the range of 1 - 4kN results in more severe porosity reduction than that out of the range; the pore size distribution of lignite is significantly changed by vibrating hot -pressing dehydration; the pores filled with water collapses and develops to smaller pores as water being gradually removed with increasing temperature and pressure, results in the severe reduction of inter - particle pores and macro - pores and slightly increase of meso - pores ; the particle structure and size distribution is changed by vibration force, and inter - particle pores are more closely arranged; the mean pore diameters of lignite significantly decreases with the increase of temperature and pressure; the specific surface areas of lignite slightly decreases under 100 ℃ and 5MPa, and then slightly increases ; the vibration force has little effect on mean pore diameters and specific surface areas of lignite.