An evaporator removing 30000 kg of water while concentrating an aqueous solution from 10% to 40% solids handles a total solid mass in kg equal to___________________?
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Answer: A. 4000
Explanation
Mass balance principles state that the total mass of dry solute must remain constant during evaporation. Multiplying the final solution mass by its solid mass fraction equals the initial solid mass. Solving this algebraic mass balance yields a total solid mass equal to four thousand kilograms. Evaporator mass balances involve feed, concentrated product, and evaporated water vapor streams. Solute mass does not vaporize, making it a reliable tie component for engineering calculations. Concentration changes reflect pure solvent removal rather than any loss of dissolved solids.
Industrial evaporator design relies heavily on solute mass balances to determine feed rates and production. Monitoring solid concentrations ensures product specifications are met in chemical crystallization units. Accurate material accounting prevents overloading downstream filtration and drying equipment. Incorrect algebraic setups or arithmetic calculation errors lead to erroneous solid mass totals. Failing to use solute mass as a tie component violates fundamental conservation laws. Alternative options represent partial fractions or incorrect feed concentration interpretations.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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