The rapid pyrolysis of 3 different ranks of coals

including lignite from Inner Mongolia

bituminous from Shenfu coalfield，and anthracite from Guizhou

has been carried out in a high-frequency furnace which could sharply reduce the secondary reactions.The pyrolysis temperatures were ranged from 600℃ to 1200℃ with an interval of 100℃.The effects of coal rank and temperature on the yields of char

char-C， and pyrolysis gas

as well as the percentages of H2

CO

CH4，and CO2 in the pyrolysis gas produced from the primary stage of pyrolysis were investigated.Results show that both of the yields of char and char-C increase

while the yield of pyrolysis gas decreases as the coal rank increases.The yields of char and char-C decrease

and the yield of pyrolysis gas increases with the increasing temperature.The char-C yield of lignite can reach a level lower than 50% at the temperature of 1200℃.H2 and CO are the main components of the pyrolysis gas

while the contents of CH4 and CO2 are much lower.As the temperature increases

the contents of H2 and CO increase

and the contents of CH4 and CO2 decrease.The contents of H2+CO in pyrolysis gas increase with the increasing temperature.The H2+CO contents from 3 coals are all higher than 90% at the temperature of 1200℃.The H2/CO ratio of pyrolysis gas also increases as the temperature increases.Both the H2+CO contents and H2/CO ratio in pyrolysis gas from 3 coals are in the order of anthracite>lignite>bituminous.The low heating values of pyrolysis gas from all the 3 coals are higher than 11 MJ·m-3.As the pyrolysis temperature increases

the low heating values of pyrolysis gas of bituminous and anthracite decrease

while the heating values of pyrolysis gas of lignite have a peak value at the temperature about 1000℃.