Abstract: The pyrolysis characters of three kinds of low-rank coals and gasification performance of their char were studied in a fixed fluidized bed reactor. The effect of sample particle size, reaction temperature, time，and the content of O2 in fluidizing gas on test results were explored. The suitable reaction conditions for circulating fluidized bed pyrolysis coupled with gasification process were determined. The results showed that the sample particle size could hardly affect the pyrolysis process. The gas yield of coal pyrolysis increased and the char yield decreased with the increase of temperature in steam atmosphere. The highest tar yield was achieved at 600 ℃ and 20 min. The effective gas yield of circulating fluidized bed pyrolysis coupled with gasification process which can produce tar simultaneously was higher than that of coal gasification in fixed fluidized bed reactor. The higher the temperature of gasification was, the higher the effective gas yield and carbon conversion yield was. The O2 content had a little influence on syngas yield but could adjust the relative content of CO and H2 in the experimental range. It can be obtained an ideal syngas yield and effective carbon conversion yield at 900 ℃ and 15 min.

Key words: fixed fluidized bed, coal pyrolysis, char gasification