Packed Bed Systems: An insight into flexible design

Student: Mrs Kerry O'Neill  

       PhD awarded May 2001

Supervisory team: Dr F. Benyahia (Director of studies) , Dr M. Gerrard (second supervisor)

 

Background to project

External support: ICI Katalco (now SYNETIX) (Billingham)

Project summary:

The effect of particle shape and size on the performance of packed beds is investigated. By means of extensive practical work, voidage data were generated and reliable mean voidage correlations for a variety of pellet shapes and sizes have been developed. Similar extensive practical work on pressure drop in packed beds was carried out and predictive pressure drop correlations superior to Ergun equation or other published equations have been obtained. These design correlations can be used for optimisation of performance in packed bed systems. An additional dimension was included: heat transfer. Relatively simple 1-D model was employed to obtain values of overall heat transfer coefficients in packed beds with various pellet shapes/sizes.

In this work, we managed to produce 3-D plots that provide energy loss (mainly pressure drop) and an overall heat transfer coefficient (1-D model) for virtually any particle shape, provided a shape factor (like sphericity) and a tube-to-particle ratio is known. Selection of an optimum catalyst pellet shape/size becomes a little easier...

Pressure drop apparatus developed by Kerry:

 

Heat Transfer in packed systems used under the supervision of Dr Farid Benyahia at Teesside University Reaction Engineering laboratory. The pictures below depict apparatuses designed and built in the department of chemical engineering at Teesside University by Dr Farid Benyahia and his team of technicians.

Special features: the thermocouples move radially and the complete axial/radial temperature profile in the packed beds of various shape/size particles can be mapped under various flow and heat conditions.

Small heat transfer in packed bed column apparatus

Large heat transfer in packed bed column apparatus

 


Publications:

1 -"Predictive Characterization of Mean Voidage in  Packed Beds", EA Foumeny and F Benyahia. Download preprint

2 - "Correlations of pressure drop in packed beds taking into account the effect of confining wall", E. A. FOUMENY. F. BENYAHIA, J. A. A. CASTRO, H. A. MOALLEMI and S. ROSHANI. Download preprint

3- "Aspects of Design and Optimisation of Packed Bed Systems", The 1996 IChemE Research Event/Second European Conference for Young Researchers, pp 485-487, (ISBN 0 85295 374 7). K. O'NEILL. and F. BENYAHIA.

4 - "On the Global and Local Structural Properties of Packed Beds of Non-equilateral Cylindrical Particles", Particulate Science and Technology , vol 15 (3), pp 221-237 (1996). F. BENYAHIA.  Download preprint

5 - "Packed Bed Systems: An insight into flexible design", K. O'NEILL and F. BENYAHIA. The 1997 IChemE Research Event, vol 2, pp1253-1256 (ISBN 0 85295 389 5).

6 - "On the Modeling of  Flow in Packed Bed Systems", F. BENYAHIA, Particulate Science and Technology , vol 22, pp 367-378 (2004). Download preprint

7 - "Enhanced Voidage Correlations for Packed Beds of Various Particle Shapes and Sizes ",  Particulate Science and Technology , vol 23, pp 169-177 (2005). F. BENYAHIA. Download preprint

8- "Heat Transfer Studies in Packed Bed Systems". IMechE Conference Transactions, 4th UK National Conference on HEAT TRANSFER, 1995, pp 31-35, (ISBN 0 85298 950 4), F. BENYAHIA and M. Mak   download