where N is the mole of hydrogen gas produced during ECF, θH
is the hydraulic retention time in ECF cell, R is the ideal gas
constant, T is the Kelvin temperature, Z is the valence (Z =2
for hydrogen gas) and P is the pressure. To prove above infer-
ence, two parameters, gas/liquid ratio (ΓG/L) and gas/solid ratio
(ΓG/S), were determined as follows: