Utilization
of coal is currently limited to coal-fired power plants
and iron smelting, partly because of the incombustible ash in coal
and the inability of existing technologies to modify its properties.
This work investigates whether the gasification behavior of ash-free
coals (AFCs) can be modified. Sixteen different AFCs were prepared
using variously ranked coals (Eco, Cyprus, Drayton, and Hail Creek)
and extraction solvents with different polarities (N-methyl-2-pyrrolidone, ethylenediamine, 1-methylnaphthalene, and
tetralin). Next, the reactivities of the AFCs in steam gasification
at 800 °C were tested, and the results are discussed taking into
consideration their compositional differences. A combination of low-rank
coals and polar solvents produces reactive AFCs that can be catalytically
gasified under mild conditions. In contrast, AFCs extracted using
nonpolar solvents are less reactive and possibly applicable as a carbon
electrode precursor. In short, the properties of AFCs can be changed
to some extent using the appropriate combination of coals and extraction
solvents.