Procedure to estimate reactive zone height, reflux ratio and column diameter

Short-cut methods derived from conventional distillation have been foimd to be inappropriate for the estimation of reflux ratio for reactive case and new approaches have been adopted. Methods derived from the boundary-value approach (c/. 3.2.4) allow the determination of the minimum and real reflux ratio, which are key factors in the determination of vapor and liquid velocities. The reflux ratio can be calculated using an iterative procedure, described in Subawalla and Fair (1999) and summarized in figure 3.9. 

The proposed approach may be extended by incorporating hydraulic models which account for the column capacity in terms of pressure drop and for mass-transfer efficiency estimations in terms of liquid hold-up, mass-transfer coefficients and interfacial area. 

Advantages this method estimates easily several equipment and/or operational variables. 

Limitations this method is basically a post-design algorithm and as such it requires an already defined process structure. 

Ge Thermodynamic-based Gy Gonventional graphic techniques Gg Phenomena-based Gg Difference points My MINLP M2 OCFE M3 MIDO Hi Heuristics. Key. I applicable nonapplica-ble/nonmentioned A original assumption relaxed by later contributions 

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Figure 3.9. Procedure to estimate reactive zone height, reflux ratio and column diameter for a catalytic distillation column (adapted from...

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