Characteristics of pore structure and specific surface area of lignite

In order to reveal the characters of lignite pore structure and specific surface area, samples were collected from the major lignite-producing areas in China, the measurement of maceral content and the low temperature nitrogen adsorption test were conducted, the micropore characteristics of coal reservoir were described from the form of adsorption curves, specific surface area and distribution of aperture configuration, the relationship between pore structure and specific surface area was discussed, the correlation of BET specific surface area and marcerals was analyzed. The results showed that the tracing patterns of low temperature liquified nitrogen adsorption of lignite samples could be roughly classified into three kinds:loop without adsorption, adsorption loop with turning point and adsorption loop without turning point. BET specific surface area showed the trend of linear increases with total pore volume. In the range of 2 to 10 nm, the relationship of specific surface area and aperture could be positively correlated, negatively correlated and compoundly correlated. The correlation of maceral group and specific surface area was weaker, but specific surface area and attrinite content had good linear correlation.