无烟煤液氮吸附测试的粒度效应

Effects of Particle Size for Anthracite Nitrogen Adsorption Test

煤的粒径大小对其孔隙结构会产生一定影响,从而改变其吸附性能。基于液氮吸附实验的基础上,对比分析不同粒径无烟煤的阶段孔容、阶段比表面积与孔径的分布关系,找出一定关系并解释其影响机理。结果表明较大的粒径（10 mm、6 mm）无法真实反映无烟煤煤中的孔隙结构;而粒径0.42 mm时无烟煤孔隙系统遭受破坏,特别是对孔径〈6 nm的孔隙破坏更甚;5~1mm粒径能较真实的反映无烟煤的孔隙结构。样品破碎过程中微裂缝的产生使孔径〈6 nm的孔隙与微裂缝沟通转变为缝宽〉6 nm的微裂缝,导致孔径〈6 nm孔隙的孔容、比表面积减小;另一方面孔喉的割裂将封闭孔转变为半封闭孔或开放型孔,致使孔径〉6 nm孔隙的孔容、比表面积增大。

The size of coal particle had a certain effect on coal pore structure, which leaded to the change of coal gas adsorption per- formanee. Based on the liquid nitrogen adsorption experiment of different particle size anthracite, we comparatively analyze the relation- ship between stage pore volume （stage pore surface area） and pore size distribution, and identify a certain relationship and explain the mechanism. The results showed that the larger particle size （10 mm, 6 mm） can not be a true reflection of the anthracite pore struc- ture. The pore structure system encounters damage while anthracite particle size is 0. 42 mm, especially for the diameter 〈 6 nm of pore. Anthracite particle size from 5 mm to 1 mm can be a true reflection of the anthracite pore structure. Diameter 〈 6 nm of pore pro- ducing during microfissure crushing of sample communicating with microfissure and transferring to microfissure that diameter 〉 6 nm leads to decrease of pore volume and surface area for diameter 〈 6 nm of pore. On the other hand, the closed pore transfer into semi - closed pore or opened pore by pore throats splitting leads to the increase of pore volume and surface area for diameter 〉 6 nm of pore.