Study on the Pore Structure of Oil Shale During Low-Temperature Pyrolysis

Abstract

In this research, effects of final pyrolysis temperature and heating rates on the pore structure of Huadian oil shale were investigated experimentally. The pore structure of raw and semi-coke samples was measured by the method of low-temperature adsorption of nitrogen. The obtained adsorption/desorption isotherms of these samples were similar and could be categorized as type II isotherms in the IUPAC classification, and all hysteresis loops produced by OS and all semi-cokes are very similar to H3 hysteresis loops. Specific surface area was calculated based on BET equation, and specific surface area distribution and pore size distribution were calculated by BJH method. The analysis results show that final temperature and heating rate are all parameters that influence specific surface area, specific pore volume and the development of mesopores. With the final temperature increase, specific surface and total pore volume initially decrease, then increase in large scale. Meanwhile the peak near 3nm on specific surface area and pore size distribution curves is gradually disappearing, then arise sharply. Lower heating rate favors the development of pores, especially 3nm mesopores. With heating rate increase, specific surface area and total pore volume decrease, and the peak value on specific surface distribution and pore size distribution curves gradually decrease.