To reveal the CO,
CO
2
, and O
2
adsorption
properties of two bituminous coals at different pressures and temperatures,
the molecular unit-cell structures of two types of bituminous coal
are constructed (C
1180
H
960
O
120
N
20
and C
1160
H
860
O
80
N
20
) by Fourier transform infrared (FTIR) spectroscopy. The bituminous
coal molecular FTIR spectroscopic curve is calculated by quantum chemistry,
and the results are consistent with the experimental curve. The isothermal
adsorption curves of the single-component gases CO, CO
2
, and O
2
conform to the Langmuir equation from 20 to 60
°C. The adsorption simulations are mainly performed using grand
canonical Monte Carlo (GCMC) methods. The amount of adsorption decreases
with increasing temperature at the same pressure, and CO
2
can be the first to reach adsorption saturation at the same temperature.
The CO
2
/CO adsorption selectivity for binary gas mixtures
has apparent advantages in low-pressure or shallow buried coal seams.
The adsorption selectivity of O
2
/CO varying under different
pressures is not obvious. The high amount of CO inhibits the adsorption
capacity of CO
2
and O
2
. In other words, the
effect of injecting CO
2
to control fire extinguishing in
bituminous coal seams with high abnormal CO concentrations is not
significant.