Investigation on the thermal performance of a sodium sulfate CFB evaporator

Abstract

To solve the serious scaling problem and low thermal performance in the evaporation process of sodium sulfate solution, a circulating fluidized bed (CFB) evaporator is designed and built to study the effect of particle type and size on its thermal performance based on our previous research. Different sizes of SiC, glass bead (GB), and polyformaldehyde (POM) particles are selected as inert particles. A series of experiments is performed with different operating parameters. Results showed that the thermal enhancement effect relates to particle type and size. At low particle volume fraction ε, the effect is in the order of SiC, POM, and GB particles. At high particle volume fraction ε, the effect is in the order of SiC, GB, and POM particles. In addition, the enhancement effect of SiC1 is less than that of SiC2. For GB particles, the enhancing factors E first decrease and then increase with the increase in particle size. For POM particles, the enhancing factors E are affected by the operating parameters. 3D diagram of enhancing factors E are established. The findings of this study may widely facilitate applying CFB technology to sodium sulfate industry.