Experiment of drying rapeseed by spouted bed with a porous branch rotating draft tube

For improving drying performance of annulus region in rotating draft tube spouted bed (RDTSB), a novel porous branch rotating draft tube spouted bed (PBRDTSB) was designed and tested with rapeseed. Taking heat consumption per kilogram water, the maximum temperature and average temperature of rapeseed in the drying process as criteria respectively, a scheme of orthogonal experiment with four factors and four levels was given and tested. For heat consumption per kilogram water, the optimum technological parameters were 130.0℃ of hot air temperature, 58.0 m3/ h of normal air flow rate, 75.0 mm of distance between draft tube and spouted jet and 67.0% of opened pore percentage. The optimum heat consumption per kilogram water was 2736.8 kJ, less than the RDTSB’s 3941.4 kJ. The results show that the introduction of the porous branch can reduce heat consumption of drying, and it should be considered for scaling up conventional spouted bed.