Distillation

Step 1: Understanding reflux conditions.
When the reflux stream is below its bubble point (i.e., in the subcooled liquid state), it requires more heat to vaporize and increase the amount of vapor in the system. This increases the reboiler load, as more heat is required to generate vapor from the liquid in the reboiler. However, the condenser load remains relatively constant because the condenser’s primary function is to condense the vapor into liquid, which is not significantly affected by the subcooled reflux stream in this case.
Step 2: Conclusion.
The correct answer is (3), where the reboiler load is higher in case 2 compared to case 1, but the condenser load remains the same in both cases.

Step 1: Understanding the equations.
Gilliland’s equation and Underwood’s equation are both used in the design and analysis of distillation columns. Gilliland’s equation is used to determine the number of real trays based on the minimum reflux ratio and the tray efficiency. Underwood’s equation is used to calculate the minimum reflux ratio and the number of ideal trays for a given distillation process. Together, these equations help in determining the number of real trays and the tray efficiency in distillation columns.
Step 2: Conclusion.
The correct answer is (2), as Gilliland’s and Underwood’s equations are used to calculate the number of real trays and tray efficiency.

Step 1: Understanding the problem.
In batch distillation, the amount of the residue and distillate is related by the material balance. The given linearized equilibrium curve equation is: We are asked to determine the number of moles of residue when the mole fraction of A in the residue decreases to 0.6. The mole balance on the system, in terms of the moles of residue and distillate, can be written as: Step 2: Applying the material balance.
Since the feed consists of 100 mol with a mole fraction of 0.7 for A, we can calculate the amount of A in the feed: Now, let the number of moles in the residue be . The mole fraction of A in the residue is given as 0.6, so the moles of A in the residue are . Using the equilibrium equation and considering the material balance, the correct answer is found to be 45 mol of residue.
Step 3: Conclusion.
The number of moles of residue is 45 mol. The correct answer is (3).