Analysis of pressure fluctuation signals in the underfeed circulating spouted bed

The underfeed circulating spouted bed (UCSB) was designed as a new dry desulfurization reactor. In this article, pressure fluctuations along the axial direction were measured and time, frequency and Shannon entropy analysis of pressure signals were studied under different operation parameters. The results indicate: the pressure fluctuations express different characteristics at various axial locations. And the operation parameters have significant influence on the flow characteristic in the riser. Advancing the spouting velocity or the circulating ratio, the solid concentration in the riser increases and the amplitude of the pressure fluctuations rises. With higher injecting velocity or nozzle position, the gas–solid turbulence in the bottom bed gets more intense. It shows that the existence of injecting flow near the underfeed nozzle has a distinct effect on strengthening the particle mixing. The power spectrum density acquired from the signals can coincidently reflect the dynamic behavior of the gas–solid flow in the riser. Analysis of Shannon entropy also corresponds to the above summarization of flow characteristic very well.