25000 kg/h of flaked soybean containing 25% oil is to be leached with n-hexane in a countercurrent

flow system. The flowrate of the solvent is 15000 kg/hr, contaminated with 5% of soybean oil.

During the commissioning phase, the experiment shows that the exit underflow stream contains

15% of total oil present in the mixture. Table 1 shows the concentration data for the exit underflow

stream.

a) Calculate the flowrate and composition of the outlet products and determine the number of stages.

b) Determine the percentage of oil extracted from overflow stream at stage = 2.

Table 1 Concentration (kg oil/kg solution) 0.0 0.1 0.2 0.3 0.4 Solution retained (kg/kg solid) 0.5 0.505 0.515 0.530 0.550 0.571 0.595 0.62 0.5 0.6 0.7