Abbreviations
BF	Blast furnace
PCI	Pulverised coal injection
CCU	CO2 capture and conversion unit
RAFT	Raceway adiabatic flame temperature
tHM	Tonne of hot metal
Roman and Greek symbols
$\mathrm{E}$	Energy, kWh/tHM or kgce/tHM
$\mathrm{V}$	Volume of gas, m3/tHM
T	Temperature, °C
${\mathrm{C}}_{\mathrm{i}}$	Specific heat capacity, kJ/m3$·$°C
${\mathrm{K}}_{\mathrm{i}}$	Reaction equilibrium constant of reduction stage i; i = I, II, III
G	Gibbs free energy, kJ/mol
$\mathsf{\phi }$	Volume fraction of gas component
${\mathsf{\eta }}_{\mathrm{i}}{}_{\mathrm{CO}}$	Utilisation efficiency of CO in stage i, i = 1, 2, 3
${\mathsf{\eta }}_{\mathrm{i}}{}_{{\mathrm{H}}_2}$	Utilisation efficiency of H2 in stage i, i = 1, 2, 3
$\mathrm{n}$	Minimal CO required for iron ores reduction, mol
$\mathrm{m}$	Minimal H2 required for iron ores reduction, mol
${\mathrm{X}}_{\mathrm{i}}$	Volume reaction of CO or H2 in reducing gas entering the BF shaft
$\mathsf{\eta }$	Overall gas utilisation efficiency for H2-rich reducing gas in the BF
$\%\left(\mathrm{Reducing} \mathrm{gas}\right)$	Proportion of H2 and CO in the total amount of gas entering the bosh and shaft.
$\mathrm{Q}$	Sensible heat of material, kJ/tHM
$\mathrm{H}$	Enthalpy of material, kJ/tHM
${\mathrm{R}}_{\mathrm{d}}$	Degree of direct reduction
${\mathrm{r}}_{\mathrm{i}}$	Degree of indirect reduction
${\left(\mathrm{Fe}\right)}_{\mathrm{HM}}$	Iron content in hot metal
$\Delta {\mathrm{H}}_{ }^0$	Enthalpy of reaction, kJ/tHM
$\mathrm{w}$	Weight fraction of solid material
${\mathrm{H}}_{2\mathrm{inj}}$	Total H2 injection volume to the BF, m3/tHM