Tables I and II present some calculated values from
gas chromatographic data. Based on the ultimate analyses
of coals, the oxygen contents (with organic matter)
of Hutar and Bachra coal are 23.5 and 15.9 wt pct, respectively.
Since this oxygen is removed with volatiles
and gases during devolatilization, it provides the value
of the theoretically removable oxygen in coal (column 3,
Table I).
Total oxygen loss associated with evolution of CO and
CO2 (AWo) was calculated by graphical integration of
14zo using Eq. [11]. These values are shown in Table I
(column 4). An interesting observation is that AWo is
much larger than the theoretical oxygen content of coal
(as explained previously). Likely causes are the binder
and the pelletmaking procedure. The binder contained 6
pct CaO. It also contained moisture present as chemically
combined water in Ca(OH)2 and hydrothermal
bonding in addition to strongly adsorbed water. Since
during the pelletmaking procedure pellets are exposed to
ambient air, absorption of CO2 to form CaCO3 to some
extent also is possible. In addition, the coal and alumina
etc. may contain and can pick up some H20 as water of
combination or as strongly adsorbed H2O.
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