Experimental investigation of models for fluidized bed catalytic reactors

Abstract

The countercurrent backmixing model of a fluidized bed reactor predicts axial concentration profiles quite different from those suggested by simple two‐phase models. The models can also be distinguished in terms of the dependence of conversion on operating variables.An experimental study of ozone decomposition in a reactor of 22.9 cm diameter has provided extensive data for comparison with backmixing and two‐phase models which incorporate bubble size variation. The measured profiles show a minimum concentration within the bed at gas velocities above a critical value, as predicted only by the backmixing model. The effect of operating variables on the shape of the profiles is also well accounted for by this model. The backmixing model is further supported by good agreement between predicted and measured reactant conversion. In particular, the variation of conversion with rate constant and gas velocity is fitted more accurately by the backmixing model than by two‐phase models.

Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

“…The ozone enters the bed at 1.5 cm from the bottom, while Barracuda calculations have ozone entering at the bottom. As noted by Fryer and Potter (1976) this gives an effectively shorter ozone decomposition zone. A 11.5 cm deep bed has a 13% smaller effective reaction zone.…”

“…10. The measured minimum fluidization velocity (U mf ) was 1.7 cm/s (Fryer and Potter, 1976), and from Fig. 10, the calculated U mf is approximately 1.6 cm/s.…”

“…The experiment by Fryer and Potter (1976) is modeled. The experiment vessel was 22.9 cm diameter and 200 cm tall.…”

“…The first report describes validation of the heterogeneous gas chemistry. The ozone decomposition experiment by Fryer and Potter (1976) was used to validate the heterogeneous chemistry. The second report describes gassolid chemistry.…”

CFD simulation of gas—solid bubbling fluidized bed: an extensive assessment of drag models

“…Such measurement has been believed to be highly biased, and, more importantly, no standard errors or deviations of data have been reported [8]. Fryer and Potter [9] reported that the experimental technique might well underestimate the bed expansion due to the diffusing characteristic of the bed surface. The other frequently employed method is to plot the time-mean gauge pressure (single-point pressure) against the height of the pressure transducer taps, where the intersection of the two slopes corresponds to the height of the expanded bed.…”