Adsorption isotherms of $H_2$, CO, and $CO_2$ on activated carbon were determined, where pressure was up to 15atm and temperatures were 25℃, 50℃, and 70℃. The effects of various parameters, such as adsorption constant, mass transfer coefficient, velocity, pressure, and concentration, on adsorption and desorption in a packed column of activated carbon were studied.
Because of nonlinear type isotherm, mass transfer coefficient was estimated by numerical analysis under various flow rates and pressures. The mass transfer coefficient of CO was represented by the following equation :
$Sh = \frac{0.353}{ε}Re^{0.82}Sc^{0.35}$
and the mass transfer coefficient of $CO_2$ was 0.043.
Freundlich and Langmuir isotherm agreed with experimental data fairly well. The affinity of gases to the activated carbon increased in sequence of $H_2$, CO, and $CO_2$.
The effects of adsorption constant and velocity on breakthrough curves were the most important. The linear driving force model predicted experimental results well. Because the adsorption contants of carbon monoxide are smaller than those of carbon dioxide, the breakthrough of carbon monoxide appeared earlier. As mass transfer coefficient was decreased the curves were broaden. When pressure was increased, at constant velocity, breakthrough time decreased. But, at constant flow rate, breakthrough time increased with increasing pressure. At constant contact time, the breakthrough curves of carbon dioxide was little affected by velocity change. On the other hand, the mass transfer zone of carbon monoxide decreased with increasing velocity at constant contact time.
