The slope of the 9-line is established by the ______________________?
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Answer: C. Thermal condition of the feed
Explanation
Feed thermal condition dictates the enthalpy state and slope of the q-line. Liquid fraction and vapor fraction of entering feeds determine q-line slope values. McCabe-Thiele graphical methods use feed q-lines to intersect stripping and rectifying operating lines. Distillation column feeds can enter as cold liquids, saturated liquids, or superheated vapors. The q-parameter represents the fraction of feed that is liquid in the column. Operating lines in distillation design connect top and bottom mass balances across trays.
Chemical engineers use q-line slopes to locate feed tray locations in distillation columns. Preheating distillation feeds changes the q-line slope and affects internal column vapor flows. Accurate feed condition analysis prevents improper column staging and product purity failures. Reflux ratio establishes the slope of the rectifying section operating line instead. Plate efficiency measures actual mass transfer performance rather than feed thermal states. Relative volatility determines equilibrium curve shapes rather than feed q-line slopes.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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