Regeneration of granular activated carbon loaded with toluene - Comparison of microwave and conductive heating at the same active powers

This paper presents a comparison of the microwave and conductive heating regeneration of granular activated carbon loaded with toluene at the same active powers. The purpose of this research was to compare desorption efficiencies and local temperature profiles for the both regeneration methods. Mass balance in the adsorbent bed was carried out by automatic sampling of the outlet gas for the GC analysis instead of weighting the adsorbent bed itself. Five experimental series were performed at constant active power of 12 W and at changing active power in the two-stage program (24 W + 12 W). It was found that the mass profiles of desorbed toluene versus time were practically overlapped for the two regeneration methods when the same active power was applied and the non-insulated vessels were used. Moreover, another comparison demonstrated that proper thermal insulation can be a decisive factor when choosing a particular regeneration method in terms of its economic viability. A comparison of the textural properties of the fresh and regenerated (after 10 successive adsorption/desorption cycles) granular activated carbon (GAC) revealed only slight differences between them. Therefore, it was concluded that the adsorption capacity of GAC is only slightly affected by the both regeneration methods.