You are processing halibut livers that contain approximately \(25.2 \mathrm{wt} \%\) fish oil and \(74.8 \mathrm{wt} \%\) insoluble solids. The following data for leaching fish oil from halibut livers using diethyl ether solvent are given by Brown et al. \((1950)\) :

where \(\mathrm{y}_{\mathrm{oil}}\) is the mass fraction oil in the overflow, which was found to contain no insoluble solids, and \(\mathrm{Z}\) is the pounds of solution per pound of oil-free solids in the underflow.

a. Convert the data to the mass fraction of oil and solvent in the overflow and to mass fraction of oil, solvent, and solids in the underflow. Plot saturated extract and raffinate curves with tie lines on a graph with \(\mathrm{y}_{\text {oil }}\) or \(\mathrm{x}_{\text {oil }}\) as the ordinate and \(\mathrm{y}_{\text {solids }}\) or \(\mathrm{x}_{\text {solids }}\) as the abscissa. Develop the conjugate line.

b. \(1000.0 \mathrm{lb}\) of fish (oil + solids) is mixed with \(500.0 \mathrm{lb}\) of pure diethyl ether. The mixture settles and the solvent layer is drawn off. Calculate the weight fraction of oil in the extract and raffinate layers and the amounts of extract and raffinate.

c. The raffinate from step \(\mathrm{b}\) is now mixed with \(500.0 \mathrm{lb}\) of pure diethyl ether. After settling, calculate the weight fraction of oil in the extract and raffinate layers and the amounts of extract and raffinate.

d. We have a total of \(1000.0 \mathrm{lb}\) of fish (oil + solids)/h. We continuously mix the fish with \(500.0 \mathrm{lb}\) of pure diethyl ether \(/ \mathrm{h}\) in a thickener and draw off the solvent layer. Calculate the weight fraction of oil in the extract and raffinate layers and the flow rates of extract and raffinate.

e. The raffinate from step \(\mathrm{d}\) is now mixed with \(500.0 \mathrm{lb} / \mathrm{h}\) of pure diethyl ether in a second thickener. Calculate the weight fraction of oil in the extract and raffinate layers and the flow rates of extract and raffinate.

f. \(1000.0 \mathrm{lb}\) of fish (oil + solids)/h are continuously processed in a countercurrent cascade of thickeners. Use \(500.0 \mathrm{lb} / \mathrm{h}\) of pure diethyl ether. We want the outlet raffinate to contain \(2.0 \mathrm{wt} \%\) fish oil. Find the number of stages required.

Transcribed Image Text:

Yoil 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.65 0.70 0.7. Z= 0.205 0.242 0.283 0.339 0.405 0.489 0.600 0.672 0.765 0.8