This study compares the performance of a new three-channel coaxial nozzle with a conventional Schlick nozzle in fluidized bed particle coating. The new nozzle produces droplets with a Sauter mean diameter of around 10 μm, offering a middle ground between aerosol and conventional nozzles. Yields of processes, coating coverages of particles, coating thickness and surface roughness were compared for the same experimental conditions of these nozzles. Non-porous glass particles (mean diameter 653 μm) and porous γ-Al2O3 particles (mean diameter 610 μm) were used as cores, with an aqueous sodium benzoate (NaB) solution as the coating liquid. A scanning electron microscope (SEM) was utilized to capture images of the particles after each experiment. To analyze the coverage on the particle surfaces, MATLAB image processing was applied to SEM images of coated particles. Moreover, these images were used to determine the surface roughness of the coating. In addition to manual measurements of coating thickness on particles by image processing, some coated γ-Al2O3 particles were sectioned to measure the coating thickness by ImageJ. The manual thickness measurements were supplemented by results obtained by laser scattering. The coating process by means of the new nozzle was also compared with an aerosol coating process which has droplet size with a mean diameter of around 1 μm, in terms of process yield, product coating coverage and thickness. The new nozzle acts as an intermediate between the aerosol generator and the conventional Schlick nozzle in terms of droplet size. These findings suggest that the new nozzle has significant potential for use in fluidized particle coating, as an alternative to conventional nozzle, offering smaller droplet size.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |