Use the Peng-Robinson VLE correlation in Aspen Plus to solve Problem 2.D13, part \(\mathrm{b}\), except feed is a saturated liquid at 10.0 bar. Pressure is dropped to 6.0 bar in the flash drum. Report the values of \(\mathrm{x}\) and \(\mathrm{y}\) methane, \(\mathrm{T}_{\text {drum }}\), and \(\mathrm{Q}\) in \(\mathrm{GJ} / \mathrm{h}\).

Problem 2.D13

We flash distill a mixture of methane and n-butane at \(\mathrm{p}_{\text {drum }}=6.0\) bar.
a. Use the DePriester charts or Eq. (2-28). For several temperatures from \(\mathrm{T}=\) \(-60^{\circ} \mathrm{C}\) to \(\mathrm{T}=50^{\circ} \mathrm{C}\), calculate the values of \(\mathrm{y}\) and \(\mathrm{x}\) in equilibrium. Plot equilibrium curve of \(y_{\text {methane }}\) versus \(x_{\text {methane }}\) and plot temperature \(T\) as the ordinate versus \(\mathrm{x}_{\text {methane }}\) (abscissa). (Note: It is convenient to plot \(\mathrm{T}\) versus \(\mathrm{x}\) on the \(\mathrm{y}\)-x graph placing the \(\mathrm{T}\) scale on the right side of the diagram.)

Eq. (2-28)

b. If the feed rate is \(250.0 \mathrm{kmol} / \mathrm{h}\), feed is \(40.0 \mathrm{~mol} \%\) methane, \(\mathrm{V} / \mathrm{F}=0.70\), and \(\mathrm{p}_{\text {drum }}=6.0\) bar, find \(\mathrm{x}, \mathrm{y}, \mathrm{T}_{\text {drum }}, \mathrm{L}\), and \(\mathrm{V}\).

c. If the vapor from part \(\mathrm{b}\) is partially condensed and the mixture is sent to \(\mathrm{a}\) second flash drum also at 6.0 bar, what fraction vaporized will give a liquid product that is \(40 \mathrm{~mol} \%\) methane? What are the values of \(\mathrm{y}, \mathrm{T}_{\text {drum }}, \mathrm{V}\), and \(\mathrm{L}\) for the second flash drum?

Transcribed Image Text:

ln K = a/T + a/T + a + a In p + a2/p+a3/p apl