3000 kg/h of tung meal containing 55% mass oil is to be extracted using 12000 kg/h of solvent. The solvent contains 98% hexane and 2% tung oil. The solution adheres to the insoluble flour in the underflow at the outlet of each stage as shown below:

The tung flour is finally milled, so part of it is suspended with the upper flow at the outlet of each stage. This amount is equal to 0.05 kg of solids per kilogram of solution. The lower flow at the outlet must contain a concentration of no more than 1% by mass of oil. How many equilibrium stages are required?

3000kg/h of tung meal containing 55% mass oil is to be extracted using 12000kg/h of solvent. The solvent contains 98% hexane and 2% tung oil. The solution adheres to the insoluble flour in the underflow at the outlet of each stage as shown below: The tung flour is finally ground, so part of it is suspended with the upper flow at the outlet of each stage. This amount is equal to 0.05kg of solids per kilogram of solution. The lower flow at the outlet must contain a concentration of no more than 1% by mass of oil. How many equilibrium stages are required