The Study Of Swelling Characteristics Of Two Kinds Of YuLin Coals

China is a country rich in coal and poor in oil, and, Coal accounts for a large proportion in energy consumptive structure, therefore, the clean utilization of coal is quite important. Coal liquefaction was one of the clean utilization technology of coal. Low rank bituminous coals are good raw materials to direct liquefaction. Therefore, The study of their structure and nature is particularly significant. This will affect on the direct coal liquefaction.Swelling properties of two low rank bituminous coals and their pretreatment coals in different solvent were studied in this paper. First, The swelling process of two coal samples in the same solvent were studied. The results showed that the two coal samples had two different swelling processes: the overshoot swelling and the slow-climbing swelling, The activation energy of coal712was lower than711. The swelling dynamic process for the same coal were studied in different solvents. It showed that the swelling degree in nonpolar solvents was lower than in polar solvents. However, the activation energy was on the contrary. The swelling degree of these two kinds of coals in the mixed solvents was not higher than in single solvent. And the activation energy values in the mixed solvents was between these kinds of single solvents. It showed that the mixed solvents did not play a promote synergy; Finally, The difference of raw coal, oxidized coal and extracted coal were studied. The result showed that swelling degree of coal in oxidized coal and extracted coal were higher than in raw coal. But, the activation energy was on the contrary. Meanwhile, the structure of these coals were analyzed by the infrared spectrum. It showed that raw coal was compared with oxidiation coal, oxidiation could reduce the amount of aromatic and aliphati and increase the amount of the hydroxyl and the oxygen-containing functional groups;Compared with raw coal, the aromatic structure unit of coal samples did not changed. Extraction is mainly affected the side chains and bridge keys of basic structural unit. This two kinds of coal swelling followed the first order kinetics equation and their activation energy were lower than20kJ·mol-1.In this paper, the cross-link density of712washed coal and their five extracted coals were measured. The results showed that the greater the polarity of solvent, the higher of the extraction rate, the less the cross linking density.