1992 Volume 71 Issue 3 Pages 189-194
Effect of hydrogen pressure on the pyrolysis of coal by using a specially designed pressurized Curie-point pyrolyzer was investigated. The effects of coal type, pyrolysis temperature and catalysts, like Fe-, Ni-, and Ca-compounds, were also clarified. Raw coal and metalimpregnated coal were heated in 0.1-5 MPa hydrogen or helium at-3000°C/s to 650-920°C and the yields of char and geseous products were analyzed.
In the case of raw coals, the yields of methane and BTX (benzene, toluene, xylenes) increased with hydrogen pressure and pyrolysis temperature. The effect of pressure was most remarkable with subbituminous coal and it was observed using helium instead of hydrogen. The catalytic pyrolysis of coal depended on the kinds of metal compounds as well as in the catalytic gasification. The Ni catalyst significantly increased the yield of methane. The yield of BTX was increased by the addition of Fe or Ni, but decreased by Ca. The effect of catalyst became significant with increase of hydrogen pressure. The high BTX yield was observed with Feimpregnated coal at 5 MPa. The Fe catalyst after flash hydropyrolysis was highly dispersed in the char.
