East Inner Mongolia lignite and its ash were dewatered at certain temperatures and pressures.SEM and low-temperature nitrogen adsorption methods were used to study the surface characteristics of the lignite and the pore characteristics of the coal and ash sample before and after dewatering. Results show that the dewatering rate of the lignite reaches to 70％, and the low heating value of the sample at air dried basis increases by more than 10％. The surface of the lignite becomes smooth after thermal expression. Adsorption-desorption isotherms show that the pore characteristics and water adsorption ability of the lignite dewatered under 30 MPa have no obvious changes. While under 50 MPa, the specific surface area and total pore volume of the lignite decrease, and water adsorption ability weakens with only an adsorption rate of 58.7％. Compared with Indonesia lignite, the influence of thermal expression pressure on East Inner Mongolia lignite is not obvious. The ash contained in lignite can inhibit the changes of pore structure during thermal expression process, thus affecting the dewatering effect of thermal expression.%对蒙东褐煤及其灰分在一定温度和压力下进行脱水,利用扫描电子显微镜、低温氮吸附法研究脱水前后褐煤的表面特性及煤样和灰样的孔隙特性.结果表明:褐煤的脱水率达到70%以上,脱水后煤样的空干基低位发热量增加10%以上,且热压后褐煤的外表面相对光滑.由吸附脱附等温线表明,30 MPa热压后褐煤的孔隙特性和回水性能无明显变化.50 MPa热压后褐煤的比表面积和总孔体积均减小,吸水回潮能力减弱,回水率仅为58.7%.与印尼褐煤相比,蒙东褐煤受热压压力的影响不明显,灰分会抑制热压过程中煤样孔隙结构的变化,影响热压脱水的效果.
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