A stream of waste water containing 2 % benzoic acid is to be extracted with benzene at a rate of 2000 kg/h in order to remove 98 % of the solute. If water and benzene are assumed to be mutually immiscible and the distribution coefficient is K = Ww/wb = 1.707 at the given temperature (where Ww and Wy are the mass fractions of the solute in water and benzene phases respectively, calculate the following: (a) The minimum rate of benzene required for countercurrent separation of the mixture. (b) The number of stages required if 1.3 times the minimum solvent is used. (c) The fraction of the solute removed if the same amount of solvent is used for separation using a four-stage countercurrent cascade. (d) The amount of solvent required if the separation of 98 % is done in a five-stage countercurrent unit. (e) The total amount of solvent required for the separation in four-stage cross-current device if the same amount of solvent is fed to each stage. (Hint: Use Kremser equation
A stream of waste water containing 2 % benzoic acid is to be extracted with benzene at a rate of 2000 kg/h in order to remove 98 % of the solute. If water and benzene are assumed to be mutually immiscible and the distribution coefficient is K = Ww/wb = 1.707 at the given temperature (where Ww and Wy are the mass fractions of the solute in water and benzene phases respectively, calculate the following: (a) The minimum rate of benzene required for countercurrent separation of the mixture. (b) The number of stages required if 1.3 times the minimum solvent is used. (c) The fraction of the solute removed if the same amount of solvent is used for separation using a four-stage countercurrent cascade. (d) The amount of solvent required if the separation of 98 % is done in a five-stage countercurrent unit. (e) The total amount of solvent required for the separation in four-stage cross-current device if the same amount of solvent is fed to each stage. (Hint: Use Kremser equation
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