Regeneration behavior of solid desiccants with microwave drying

Solid desiccants have been widely used in dehumidification systems, but the regeneration of desiccants is significant for the economy and environment protection. The regeneration performance of several typical solid desiccants was examined in a microwave combined hot air lab-scale setup. The shortest time required for desiccants happened in the combined heating. Among eight desiccants, zeolite in the combined drying took the shortest time to be regenerated. Activated alumina was the most difficult to be regenerated, and it in the hot air drying had the highest absorption capacity, while 3A (1.6–2.5) zeolite in the microwave and combined heating had the highest absorption capacity. Silica gels in all heating modes had the minimum absorption capacity. At low power levels (100-300W), the regeneration performance of the silica gels was prompted by the multi-magnetron radiation modes with the top one. The temperature distribution uniformity in silica gel was lifted with the assisted hot air drying. The multi-magnetron could ameliorate the microwave heating uniformity. The combined drying not only could lift the heating uniformity of the microwave, but also lowered the energy consumption by the traditional hot air drying alone. This study can provide basic data for the design and improvement of the desiccant rotors.