溶剂萃取对烟煤孔隙结构和粒度的影响

Nantong bituminous coal was extracted with carbon disulfide-N-methyl-2-pyrrolid-inone (CS2-NMP) mixed solvent, acetone and pyridine, and all the residue was gained. Sorption behaviors of nitrogen and granularity of the coal and extract residue, were tested using Accelerated Surface Area and Porosimetry (ASAP) 2010 apparatus and scanning electron microscope. The BET specific area of the samples, the distribution regulation of BJH pore volume and BJH pore area according to the pore radius, and the influence of the extraction behavior on the granularity were studied. The results showed that through “dissolving” the small molecule substance the solvent extraction will improve the adsorption ability, the specific area of the pore and the character of pore space, and decrease the granularity, but not break the basic structure unit of coal. The solvent extraction of coal belongs to physical behavior essentially. The specific area varies from 187 m2/g to 318 m2/g, and the pore volume varies from 0.175 m3/g to 0.535 m3/g. The most probable pore radius for the original coal and its solvent extract residua is all about 0.72 nm. According to the most probable pore radius, the diameter of basic structure unit of the coal was calculated for about 3.5 nm. The result approved the assumption on the colloidal group structure model of coal molecule.