When a distillation column feed consists of saturated liquid, the slope of the feed q-line is_____________________?
Show answer Hide answer
Answer: C. Infinity
Explanation
A saturated liquid feed enters a distillation column precisely at its bubble point temperature without flashing. Because no extra thermal energy is supplied to vaporize any feed, the q-line representing the feed condition is vertical. A vertical line on an x-y diagram possesses an undefined slope mathematically classified as infinity. The feed q-line equation on a McCabe-Thiele diagram determines where rectifying and stripping operating lines intersect. The parameter q represents the fraction of liquid in the feed stream entering the distillation column stage. For a saturated liquid feed, every mole of feed added joins the liquid flow going down the stripping section.
Option A is incorrect because a zero slope represents a saturated vapor feed entering the column. Option B is incorrect because a unity slope corresponds to a partially vaporized feed condition. Option D is incorrect because infinity is the established correct slope for a saturated liquid feed q-line.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Co-current absorbers are typically selected when the gas being dissolved into the liquid is a/an ___________________?
Show answer Hide answer
Answer: B. Pure gas
Dissolving pure gases eliminates concentration gradients within the gas phase boundary layer. Co-current absorbers lack concentration driving force limitations when handling pure soluble gases. Pure gas absorption procee...
Q2. Air relative humidity decreases despite rising absolute humidity whenever ____________________?
Show answer Hide answer
Answer: A. Temperature rises
Relative humidity is defined as the ratio of water vapor partial pressure to saturation vapor pressure. An increase in air temperature raises the saturation vapor pressure exponentially faster than partial pressure. Cons...
Q3. When the liquid and vapor phases of a binary mixture obey Raoult’s and Dalton’s laws respectively, relative volatility is expressed as the ratio of________________________?
Show answer Hide answer
Answer: A. Vapour pressure of component A to that of component B
Relative volatility measures the ease of separating two components in a binary mixture via fractional distillation. When liquid and vapor phases obey Raoult's and Dalton's laws, mole fractions substitute directly using p...
Q4. Which of the following industrial processes is not directly related to mass transfer ?
Show answer Hide answer
Answer: D. Froude number
The Froude number is a dimensionless fluid mechanics parameter relating inertial forces to external gravitational forces. It is used primarily in open channel flow, ship hydrodynamics, and mixing impeller design rather t...
Q5. Heating an unsaturated air-water vapor mixture at constant pressure results in ____________________ ?
Show answer Hide answer
Answer: D. The relative humidity decreases
Heating air at constant pressure increases its temperature, which immediately raises its saturation vapor pressure. Because the actual moisture content remains unchanged during dry heating, the water vapor partial pressu...
Q6. What constitutes the primary controlling factor governing drum dryer operation ?
Show answer Hide answer
Answer: B. Heat transfer
Drum dryers operate by applying a thin layer of liquid slurry onto the outer surface of a rotating heated metal drum. Thermal energy conducts rapidly through the metal wall to supply the latent heat required for surface...