Under what circumstances will both the operating and equilibrium lines in an absorber be linear_______________________?
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Answer: C. Dilute solution and isothermal operation
Explanation
Dilute solutions maintain nearly constant total molar flow rates throughout the absorption column height. Isothermal operation ensures that the equilibrium partition coefficient remains constant across all stages. Constant flow rates and constant partition coefficients produce straight operating and equilibrium lines. The operating line represents mass balance relationships between the gas and liquid bulk phases. The equilibrium line relates the solute concentration in gas and liquid at thermodynamic phase equilibrium. Curvature in mass transfer lines typically arises from significant heat effects or high solute concentrations.
Analytical shortcut methods like the Kremser equation require linear operating and equilibrium lines. Environmental air pollution control absorbers often operate under dilute and isothermal conditions. Simplifying assumptions of linearity make manual preliminary design calculations much faster and easier. Concentrated solutions cause significant molar flow variations leading to curved operating lines. Non-isothermal operation causes temperature fluctuations that change equilibrium coefficients and curve the lines. Concentrated solutions and non-isothermal conditions both introduce severe curvature into system design lines.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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