268099 Practical Application of Column Profile Maps: Distributed Feed Crude Distillation Column

Tuesday, October 30, 2012: 5:20 PM
408 (Convention Center )
Emmanuel Kasese, School of Chemical and Metallurgical Engineering, University of the Witwatersrand (COMPS), Johannesburg, South Africa, Mark Peters, University of South Africa, Johannesburg, South Africa, Diane Hildebrandt, Centre of Material and Process Synthesis (COMPS), University of the Witwatersrand, Johannesburg, South Africa and David Glasser, Chemical Engineering, University of the Witwatersrand, Johannesburg, South Africa

Distillation columns with multiple feeds are often used in the process industry for the separation of multicomponent mixtures, though the energy-saving potential for different column variations like reflux reduction and stage reduction have not been fully addressed for complex columnsá(Bandyopadhyay et al., 2004). This paper will be founded on the premise that there are economic benefits in having feeds entering the column at different locations.

The CPM method, a novel graphical distillation design technique developed by Tapp et al. (2004), has already been established to be effective in distillation systems analysis and can be generalised for any number of components. This paper proposes the use of distributed feed on an Atmospheric Crude Distillation column (ACD) for a crude oil refinery with the aid of CPMs and a software simulation package (ASPEN«). Separation is not perfect in the commercial ACD, and that makes it an ideal candidate for distributed feed because of the non-sharp split product specificationsá(Holland, 2005). Since plotting CPM profiles for a system with more than 4 components makes it very hard to get a clear picture of the compositional profile plots, this issue can be circumvented by taking a representative three component mixture that fairly mimics the real multicomponent system. For the purposes of this study a constant volatility n-butane/n-decane/n-hexadecane mixture was chosen on the basis that a paraffinic crude oil would be processed. The CPM method would then be used to analyse the distributed feed scheme and the results can be generalised for the crude oil system by using the CPM results to initialise the ASPEN« simulation.

At the end of the study, the paper would have further validated the authenticity of the CPM method by having applied it on a well-established process thus proving that it has real practical applications rather than just scientific. Finally the question of whether the alternative distributed feed configuration proposed is worthy will be answered by looking at theá approximate potential savings in capital, energy as well as operating costs.

  References

Bandyopadhyay, S., Mishra, M. & Shenoy, U.V., 2004. Energy-Based Targets for Multiple-Feed Distillation Columns. AIChE, 50(8), pp.1837-53.

Holland, S.T., 2005. Column Profile Maps: A Tool for the Design and Analysis of Complex Distillation Systems. Thesis. Johannesburg: COMPS University of the Witwatersrand.

Tapp, M., Holland, S.T., Hildebrandt, D. & Glasser, D., 2004. Column Profile Maps. 1. Derivation and Interpretation. Ind Eng Chem Res, 43, pp.364-74.

 


Extended Abstract: File Not Uploaded
See more of this Session: Advances in Distillation
See more of this Group/Topical: Separations Division