(481d) Concptual Design of Multi-Side Draw Hybrid Reactive Distillation Columns for Multi-Reactant Multireaction Schemes Involving Multiple Azeotropes

The contribution deals with the development of design algorithm for multi-side draw hybrid reactive distillation (RD) column in order to obtain a desired selectivity in a multireactant multi-reaction system involving multiple azeotropes. This work is the continuation of our earlier work on selectivity engineering with hybrid RD columns [1,2,3,& 4]. Recently Hasan et al. [4] have proposed a conceptual design algorithm for single feed multi-side draw hybrid reactive distillation columns to achieve desired selectivity in single reactant multi-reaction schemes involving zeotropic mixtures. In this work we extend the approch further to show that a single feed multi-side draw hybrid RD configuration is also capable to give a desired selectivity in multi-reactant multireaction schemes involving multiple azeotropes. The developed methodology is based on combined graphical-simulation approach and utilize the concept of visualization of the locus of liquid feed stage compositions of nonreactive distillation column and its intersection with that composition in space at which reaction takes place in a multi-side draw hybrid RD column. Based on the desired product selectivity, we determine the volume slice and hence the surface of reactive stage compositions (SRSCs) in the RD column. If the reaction in the RD column takes place at any of the compositions that belongs to SRSCs then our desired selectivity is ensured. The algorithm developed in this work is applicable to any number of components as well as to the systems with any number of azeotropes but is restricted to single feed configurations and to the cases where both the reactants are saddles. However we believe that the developed approach can be conveniently extended to multi-feed configurations too. The method developed here proves to be very useful for industrially important multi-reactant multireaction systems such as production of diethyl carbonate in which both dimethyl carbonate and ethanol are saddles in the corresponding residue curve map.

References

[1] Hasan, S.U.; Mahajani, S.;Malik, R.K. Selectivity engineering with single-feed hybrid reactive distillation columns. Chemical Engineering Science.[Online] 2013, 99, 324–334.

[2] Hasan, S.U.; Mahajani, S.;Malik, R.K. A conceptual design algorithm for single-feed  hybrid  reactive  distillation  column  involving  azeotropic  systems.  Computer Aided Chemical Engineering. [Online] 2013, 32, 313–318.  

[3] Hasan, S.U.; Mahajani, S.;Malik, R.K. Selectivity Engineering with hybrid reactive distillation column with side draw. 10th International conference on Distillation & Absorption,[Online] 2014, September 14-17, Friedrichshafen,Germany. (Abstract Accepted).

[4] Hasan, S.U.; Mahajani, S.;Malik, R.K. Selectivity Engineering with Multi-Side draw Hybrid Reactive Distillation Columns. 23^rd International Symposium on Chemical Reaction Engineering (ISCRE- 23) and 7^th Asia Pacific Chemical Reaction Engineering Symposium (APCRE-7),[Online] 2014, September 7-10, Centara Grand & Bangkok Convention Centre (BCC) at Central World, Bangkok, Thailand. (Abstract Accepted).