Drying Intensity Affected to Pore Structure and Water Re- adsorption in Lignite

In order to study the drying intensity affected to pore structure and water re- adsorption in lignite, taking Baorixile lignite as the study object, four differen t drying intensity experiments were conducted at constant temperature 200。C, the different dried coal samples with different total moisture were achieved. The low- tem perature nitrogen adsorption method was applied to study the pore structure characteristics and the changing features of pore size distribution, pore volume and specifi C area of raw coal and dried coal samples. The experiment results showed that coal quality did not change significantly during drying process at 200。C. The pore struct ure characteristics of raw coal and different dried coal samples were same. Lignite adsorption isotherm all belonged to type I, and adsorption loops all belonged to typ e H3. With the improvement of drying intensity, specific area decreased firstly and then increased, the total pore volume and average pore size increased gradually. The water re- adsorption experiment results showed that re- adsorption amount increased with the incensement of mesopore. It was an effective way to restrain water re- ad sorption amount by choosing appropriate drying intensity to reduce the incensement of mesopore amount.