Heat and Mass Transfer in Process of Fluidized-Bed Spray Granulation

This article presents a mathematical model of heat and mass transfer for the process of fluidized-bed spray granulation, which can be applied in the analysis of bed temperature profile, temperature and humidity of outlet gas and moisture content of particles. Effects of operation parameters on the batch granulation are investigated. The theoretical calculation agrees reasonably well with the experimental data.

Spray granulation of Fe and C nanoparticles and their impedance match for microwave absorption

The microwave absorbents of Fe and C nanoparticles as magnetic loss and dielectric loss material respectively were composited with the polyvinyl alcohol （PVA） as binder by spray granulation method, The electromagnetic parameters of Fe and C composite particles were analyzed by vector network. The complex permittivity and magnetic permeability of Fe and C composite particles matched well with increasing C nanoparticle content, and then the microwave loss property was improved. A minimum reflection loss （RL） of -42.7 dB at 3.68 GHz for a composite with 4.6 mm in thickness can be obtained when the content ratio of the C nanoparticles, the modified Fe nanoparticles and the PVA is 21：49：30 （Sample 3）.

A study of spray granulation in vibrated fluidized bed with internal heating tubes

The granulation process in a vibratedfluidized bed with immersed horizontal heating tubes was studied in this paper,with small monoammonium phosphate particles as the initial particles and monoammonium phosphate solution sprayed on them.The concrete influences on the granulating performance of the immersed horizontal heating power,fluidizing gas velocity,vibration frequency and amplitude had been analyzed theoretically.The results show that appropriate vibration intensity is a preferred condition for the growth of partials,but thefine dust will become much more along with prolonged vibration.Increasing the heating power is beneficial to raise the growth rate.Particles will grow faster if thefluidizing gas velocity is higher,but this will cause morefine dust.The optimized condition of A=0.002 m,f=6.67 Hz,u=1.4 m/s was given after the analysis of the experimental results.In the end,a semiempirical formula was derived from the experiment data,and the calculation results show good agreement with the experimental data.

Microencapsulated β-carotene preparation using different drying treatments

β-Carotene is one of the most abundant natural pigments in foods;however,usage of β-carotene is limited because of its instability.Microencapsulation techniques are usually applied to protect microencapsulated p-carotene from oxidization.In this study,β-carotene was microencapsulated using different drying processes:spray-drying,spray freeze-dryi ng,coati ng,and spray granulation.The properties of morphology,particle size,water con tent,thermal characteristic,and chemical stability have been explored and compared.Scanning electron microscopy measure?ments showed that the coated powder had a dense surface surro un ded by starch and suggested that the coati ng process gave a microencapsulated powder with the smallest bulk density and the best compressibility among the prepared powders.The chemical stabilities of microcapsules were evaluated during six months of storage at different temperatures.The coated powder had the highest mass fraction of β-carotene,which indicated that the coating process was superior to the three other drying processes.