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CAT 2 CHP 372 2024-2025 It is necessary to separate by distillation 100 kmol/h of a process stream containing 60 mol% benzene and 40 mol% ethylbenzene, with the objective of obtaining a high purity (99.5 mol%) benzene product and an ethylbenzene product. Two schemes are to be considered: Scheme I: An initial flash separation prior to distillation, and then distill the resulting benzene rich product to remove the ethylbenzene. This process is shown schematically in Figure 1 below. The feed to the flash separator is at its boiling point, with 60% vapour. The vapour stream is then fed to a distillation column having a reflux ratio of 1. Scheme II: A direct distillation of the process stream (at its boiling point); reflux ratio of 1. Determine: a) The concentration of the vapor and liquid streams from the flash operation; b) The number of stages necessary to produce a bottoms product of 99% ethylbenzene for scheme I; c) The number of stages for the distillation column of scheme II to produce the two products of the same composition as in scheme I Equilibrium X-Y plots are included for your use. $$F, X_F$$ $$V, Y_D$$ $$L, X_B$$ Figure 1 Distillation column MOLE FRACTION BENZENE IN VAPOUR MOLE FRACTION BENZENE IN LIQUID $$y = -1.7343x^4 + 5.4308x^3 - 6.5511x^2 + 3.853x$$

          CAT 2 CHP 372 2024-2025
It is necessary to separate by distillation 100 kmol/h of a process stream containing 60 mol% benzene and 40 mol% ethylbenzene, with the objective of obtaining a high purity (99.5 mol%) benzene product and an ethylbenzene product. Two schemes are to be considered:

Scheme I: An initial flash separation prior to distillation, and then distill the resulting benzene rich product to remove the ethylbenzene. This process is shown schematically in Figure 1 below. The feed to the flash separator is at its boiling point, with 60% vapour. The vapour stream is then fed to a distillation column having a reflux ratio of 1.

Scheme II: A direct distillation of the process stream (at its boiling point); reflux ratio of 1.

Determine:
a) The concentration of the vapor and liquid streams from the flash operation;
b) The number of stages necessary to produce a bottoms product of 99% ethylbenzene for scheme I;
c) The number of stages for the distillation column of scheme II to produce the two products of the same composition as in scheme I

Equilibrium X-Y plots are included for your use.

$$F, X_F$$
$$V, Y_D$$
$$L, X_B$$
Figure 1 Distillation column

MOLE FRACTION BENZENE IN VAPOUR
MOLE FRACTION BENZENE IN LIQUID
$$y = -1.7343x^4 + 5.4308x^3 - 6.5511x^2 + 3.853x$$

cat 2 chp 372 2024 2025 it is necessary to separate by distillation 100 kmolh of a process stream containing 60 mol benzene and 40 mol ethylbenzene with the objective of obtaining a high pur 60005

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