Investigation on pyrolysis of Zhaotong lignite

Zhaotong, Yunnan Province, is rich in lignite sources. Because of high moisture, high ash content and low calorific value, it has not been used as a fuel up to now. In this paper, the investigation of the Zhaotong lignite pyrolysis has been made to find a rational method to use the lignite. The properties of lignite and its pyrolysates were discussed. The moisture of Zhaotong lignite is as high as 56%. Therefore, the drying process becomes more important. The dryness at room temperature and in the furnance was studied. The pyrolysis experiments on lignite were performed by a thermogravimetric analyzer (TGA) at four different heating rates of 5, 10, 15 and 20 degreesC/min up to a final temperature of 600degreesC. The effects of heating rates on lignite pyrolysis were discussed. The kinetic model of pyrolysis with two stage integral method has been developed and the kinetic parameters were determined from TGA data. The kinetic parameters can be available for the reference of the utilization of lignite.