1 research outputs found
Weight Loss and Tar Evolution during Coal Devolatilization at Various Heating Rates
Temperature-resolved
weight loss and tar yield during atmospheric devolatilization of pulverized
coal have been obtained on a wire mesh reactor (WMR), which imposes
prescribed thermal histories covering a wide range of heating rates
on coals from lignite to anthracite. The accuracy of measurements
has been improved by diminishing non-isothermality in the sample,
ensuring independence of yields on loading density, and the development
of a convenient tar collection method that inhibits secondary pyrolysis
but also secures capture completeness. We reconfirm the continuous
rank effects in terms of reaction dynamics and partitioning between
tar and non-condensables but at disparate heating rates of 5 and 1000
K/s. In addition, we depict the constant variation in gas evolution histories among various coals before the cessation of tar
release, whereas since the end of tar evolution, variations in gas
formation kinetics for different coals gradually shrink with increasing
temperatures. A larger fraction of total gases is found expelled after
tar evolution by coals of higher rank. The sensitivity of the tar
yield to heating rate is maintained the same over the range of 5–1000 K/s but varies with rank, being greatest for lignites
and low-volatile bituminous coals but exhibiting a minimum for high-volatile
bituminous coals