example 31.3-1 was given below

1.3-1. Constant Underflow in Leaching Oil from Meal. Use the same conditions as given in Example 12.10-1, but assume constant underflow of N=1.85kg solid/kg solution. Calculate the exit flows and compositions and the number of stages required. Compare with Example 31.3-1. Ans. yAN=0.111,xA1=0.623,4.3 stages EXAMPLE 31.3-1. Countercurrent Leaching of Oil from Meal A continuous countercurrent multistage system is to be used to leach oil from meal by benzene solvent (B3). The process is to treat 2000 kg/h of inert solid meal (B) containing 800kg oil (A) and also 50kg benzene (C). The inlet flow per hour of fresh solvent mixture contains 1310kg benzene and 20kg oil. The leached solids are to contain 120kg oil. Settling experiments similar to those in the actual extractor show that the solution retained depends upon the concentration of oil in the solution. The data (B3) are tabulated below as Nkg inert solid B/kg solution and yAkg oil A/kg solution