An insulated column for lab-scale non-isothermal breakthrough: Impact of thermal effects during CO2 adsorption

Often lab-scale adsorptive breakthrough experiments are conducted in an isothermal manner, whereas industrial-scale adsorption processes are near-adiabatic. In this work, a polyurethane (PUR) insulating column was manufactured to mimic large-scale non-isothermal behavior via laboratory-scale breakthrough tests. Breakthrough tests with a CO₂/N₂ gas mixture on zeolite 13X (∼5 g) were performed. A bed temperature increase of 62 °C and long cooling times were observed. When compared to a regular steel column, showing a temperature rise of only 12 °C, the column efficiency was approximately 20% lower due to adiabatic effects. The heat evacuated from the adsorbent bed via the column exhaust was used as a measure for the degree of adiabaticity. Up to 46% of the theoretical heat of adsorption could be detected at the PUR column exhaust compared to 4% at the steel column exhaust. The important difference between isothermal, non-isothermal and adiabatic limit behavior was demonstrated through breakthrough experiments and simulations.