The steam economy of a multi-effect evaporator relies upon the _____________________?
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Answer: A. Heat balance consideration
Explanation
Steam economy in multi-effect evaporators is determined through rigorous overall heat and mass balances. These calculations account for latent heats, boiling point elevations, and sensible heat requirements. Heat balance considerations establish how much water is evaporated per unit of fresh steam. Multi-effect evaporators reuse secondary vapors to maximize total steam economy in plants. Enthalpy balances across each effect ensure thermodynamic consistency in design calculations. Steam economy represents the mass ratio of total water evaporated to fresh steam supplied.
Industrial plant operators monitor steam economy closely to minimize operating utility costs. Heat balance models help optimize feed preheating arrangements in multi-stage evaporator loops. Poor thermal efficiency indicates fouling or improper pressure staging across the effects. Rate of heat transfer determines required surface area rather than thermodynamic steam economy. Both heat balance and heat transfer rate are needed, making option C incorrect here. Neither A nor B is incorrect because heat balances dictate the fundamental steam economy.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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