Characteristic evaluation of activated carbon applied to a pilot-scale VSA system to control VOCs

•On the pilot-scale VSA system installed in a paint factory, the adsorption/desorption were repeated 20 times during 40 days.•As the cycle increased, physical changes of activated carbon were little observed, but the toluene adsorption capacity remained at least 85%.•As the adsorption/desorption cycles are repeated, the non-desorbed physisorption can be increased in the micropores. This work investigates the characteristics of activated carbon sampled after repeated adsorption/desorption cycles to indirectly evaluate the performance of a 30m3/min pilot-scale VSA system installed in a paint factory. The onsite pilot VSA system was operated continuously for 20 adsorption/desorption cycles during a 40day period. Samples of commercial activated carbon (raw) and regenerated activated carbon after 10 cycles and 20 cycles (10A, 10B, 20A, 20B) were prepared. The changes in physical properties were analyzed based on N2 adsorption–desorption. Changes in the adsorption capacity were measured using a toluene adsorption test and DTG analysis. Depending on the VSA cycle increase, minimal physical changes in the activated carbon were observed, except for a decrease in the BET surface area. As a result of the toluene adsorption test, at 20 cycles at least 85% of the performance of activated carbon was maintained. However, as the VSA cycles were increased from 10 cycles to 20 cycles, the toluene adsorption capacity was found to be slightly reduced or maintained. Based on the DTG analysis, the cause of the performance degradation seems to be the formation of a heel, which is the non-desorbed physisorption observed for regenerated activated carbon.