Coffee beans containing 45% (by mass) useful/desired oils, fats and acids (referred to as essentials) are...

 

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Coffee beans containing 45% (by mass) useful/desired oils, fats and acids (referred to as "essentials") are extracted in a countercurrent plant. 80% of the essentials must be recovered in a solution containing 60% (by mass) essentials. The essentials are extracted from the beans using an alcohol mixture as the solvent. 1 kg of solution is removed from the underflow for every 2 kg of coffee grounds (insoluble matter) produced. Calculate the number of stages required for this application. Assume the solvent contains no essentials initially (pure solvent). Use the graphical method and a basis of 1kg of solids. (This 1kg is the total feed solids - the entire coffee bean. Alternatively use a basis of 0,55kg of insoluble coffee grounds.) Coffee beans containing 45% (by mass) useful/desired oils, fats and acids (referred to as "essentials") are extracted in a countercurrent plant. 80% of the essentials must be recovered in a solution containing 60% (by mass) essentials. The essentials are extracted from the beans using an alcohol mixture as the solvent. 1 kg of solution is removed from the underflow for every 2 kg of coffee grounds (insoluble matter) produced. Calculate the number of stages required for this application. Assume the solvent contains no essentials initially (pure solvent). Use the graphical method and a basis of 1kg of solids. (This 1kg is the total feed solids - the entire coffee bean. Alternatively use a basis of 0,55kg of insoluble coffee grounds.)