Table 6.

Acetone(1) + ethanol(2): the simulation of a rectification column to purify the acetone+ethanol binary system, using the result labeled as "2" in Figure 7, does not provide a coherent resolution because it estimates the presence of two immiscible liquid phases. The final values obtained with results 1 and 3 are detailed in Table 5, while the composition profiles are shown in Figure 12. In both cases the composition of the distillate is higher than 99% in acetone and at the same temperature in

The exact purity is slightly higher with result 1 than with result 3, the difference being 0.2%. The calculation in the bottoms of the tower reveals differences between the two parametrizations, giving place to an effluent somewhat purer in the case of result 1. The difference between both models is 0.001 in molar fraction. These observations directly affect the calculation of the energy balance and, therefore, to the consumed energy. Thus, the consumption in the condenser is estimated similarly with both parametrizations, while that of the reboiler is significantly higher with result 3, due to the greater quantity of ethanol and the incorrect estimate of

x<sup>1</sup> y<sup>1</sup> T/K x<sup>1</sup> y<sup>1</sup> T/K

 0.990 0.993 329.0 0.989 0.991 329.0 0.974 0.981 329.1 0.970 0.978 329.1 0.941 0.957 329.3 0.935 0.953 329.4 0.853 0.900 330.1 0.846 0.894 330.2 0.518 0.709 334.4 0.526 0.710 334.2 0.010 0.031 350.6 0.011 0.035 350.5

Quantities obtained in the simulation of a separation process for the binary acetone(1) + ethanol(2), using

Plot of composition and temperature profiles obtained in the simulation of a separation operation for acetone (1) + ethanol(2) system, using the different parametrizations proposed: (—) 1 (M4). L, liquid stream profile;

Qc/kJ h<sup>1</sup> 1.035E5 1.034E5 Qr/kJ h<sup>1</sup> 1.038E5 1.044E5

the stage.

Table 5.

Figure 12.

62

V, vapor stream profile.

other quantities, such as the mixing enthalpies.

Distillation - Modelling, Simulation and Optimization

different values from the efficient front shown in Figure 7.

Stage Result 1 (M4) Result 3 (M3)

Quantities obtained in the simulation of a distillation process for the binary benzene(1) + hexane(2), using different values from the efficient front shown in Figure 9.

## Figure 13.

Plot of composition and temperature profiles obtained in the simulation of a separation operation for the binary benzene(1) + hexane(2), using the different parametrizations proposed: (——) 1 (M2); (- - - -) 2 (M1); () 4 (M1). L, liquid stream profile; V, vapor stream profile.

binary dissolution with high purities (no more than 79%), due to the presence of the azeotrope at intermediate composition. The differences noted in compositions in the head and bottom of the column cause that the corresponding temperatures are also different. Between results 1 and 4, there is a difference in temperature of almost 0.5 K, while results 2 and 3 estimate lower temperatures by more than 1 K with respect to the others. In this case, the modeling errors in another of properties, such as excess enthalpies, as well as the differences in the output composition, also affects to produce noteworthy differences in the energetic consumptions of both condenser and boiler. In this sense, similar results are obtained for results 1 and 4, although, a priori, it is not possible to indicate which of these is closer to the true behavior of the column.

Acknowledgements

DOI: http://dx.doi.org/10.5772/intechopen.85743

This work was supported by the Ministerio de Economía y Competitividad (MINECO) of the Spanish Government, Grant CTQ2015-68428-P. One of us (AS) is also grateful to the ACIISI (from Canaries Government, No. 2015010110) for the support received. This work is a result of the Project "AIProcMat@N2020— Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020," with the reference NORTE-01-0145-FEDER-000006, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); Associate Laboratory LSRE-LCM—UID/EQU/50020/2019—funded

A Practical Fitting Method Involving a Trade-Off Decision in the Parametrization Procedure…

Vapor pressures of pure compounds are calculated using Antoine equation:

Parameters A, B, and C, from literature [60–62], are shown in Table A1.

Acetone 6.42448 1312.25 32.45 [60] Ethanol 7.24677 1598.67 46.42 [61] Benzene 6.03053 1211.03 52.36 [62] Hexane 5.87891 1089.49 60.55 [62]

, Elena Gómez<sup>2</sup>

Faculty of Engineering, University of Porto, Porto, Portugal

\*Address all correspondence to: juan.ortega@ulpgc.es

1 Grupo de Ingeniería Térmica e Instrumentación (IDeTIC), Parque Científico-Tecnológico, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain

2 Associate Laboratory of Separation and Reaction Engineering and Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical Engineering,

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

<sup>i</sup> =kPa ¼ A � B=½ � T=K � C (10)

A BC Ref.

, Eugénia A. Macedo<sup>2</sup> and Juan Ortega2

\*

by national funds through FCT/MCTES (PIDDAC).

log p<sup>o</sup>

A. Vapor pressure modeling

Author details

, Luís Fernández<sup>1</sup>

Parameters of Antoine equation for pure compounds in this work.

provided the original work is properly cited.

Adriel Sosa<sup>1</sup>

65

Table A1.
