Filtration, Distillation and Gas Absorption Set 2 – Exam

This unit expresses fiber thickness of individual threads of filter cloth.

Which of the following is not true regarding washing for a filtration process?

Which of the following process can filter particles with a size less than 5 nm?

This material is used to filter gelatinous particles from paints, spinning solutions, and other viscous liquids.

Most continuous filters use vacuum as driving force for filtration.When is pressure as driving force required?

Calculate the specific cake resistance in ft/lb_m from the following CaCO₃ slurry in water filtration data at 20 °C at a constant pressure of 30 kPa abs. The area of the plate-and-frame press is 0.045 m² and the slurry concentration was 25 kg solid/m³ filtrate.

V (L)    0.5       1.0       1.5       2.0       2.5       3.0

t (s)      17.3    41.3    72.0    108.3  152.0  201.7

This is the drainpipe of a tray where liquid flows from one tray to the tray below.

Which of the following factors generally favor trays compared to random packings?

Which among the following tray columns has the lowest installed cost in USD/tray?

Gas, from a petroleum distillation column, has a concentration of H₂S reduced from 0.03 (kmol H₂S/kmol of inert hydrocarbon gas) to 1% of this value by scrubbing with a triethanolamine-water solvent in a countercurrent tower, operating at 300 K and atmospheric pressure. The equilibrium relation for the solution may be taken as Y_e = 2X. The solvent enters the tower free of H₂S and leaves containing 0.013 kmol H₂S/kmol solvent. The flow of inert gas is 0.015 kmol/m²-s and the overall coefficient for absorption K_Ga may be taken as 0.04 kmol/m³-s (unit mole fraction driving force).

What is the total height of the absorber?

What is the number of overall gas-phase mass-transfer units?

A tower packed with Flexipac Type 2y structured packing (FP2Y) is to be used to remove 99.5% of the ammonia from an air stream containing an ammonia mole fraction of 0.005. The tower is to operate isothermally at 100 °F and 1 atm. The ammonia is to be absorbed in an aqueous solution of nitric acid. The tower diameter has been selected to give an F factor of 2.0 (ft/s)(lb_m/ft³)^1/2 and a liquid loading of 15 gal/min. The density of air stream is 0.0709 lb_m/ft³ and that of water is 62 lb_m/ft³. The height transfer units of thegas and liquid are 0.84 ft and 0.58 ft, respectively.

What is the liquid to gas ratio (L/G) from calculating the molar fluxes of the gas and liquid?

A tower packed with Flexipac Type 2y structured packing (FP2Y) is to be used to remove 99.5% of the ammonia from an air stream containing an ammonia mole fraction of 0.005. The tower is to operate isothermally at 100 °F and 1 atm. The ammonia is to be absorbed in an aqueous solution of nitric acid. The tower diameter has been selected to give an F factor of 2.0 (ft/s)(lb_m/ft³)^1/2 and a liquid loading of 15 gal/min. The density of air stream is 0.0709 lb_m/ft³ and that of water is 62 lb_m/ft³. The height transfer units of thegas and liquid are 0.84 ft and 0.58 ft, respectively.

If Henry’s constant for ammonia is 1.72 atm, what is the height of the packing for physical absorption at the same conditions?

This is the most common operating regime in distillation whereeach perforation bubbles vigorously.

Which of the following is the appropriate solvent for the extractive distillation of benzene and cyclohexane?

Which of the following is the appropriate entrainer for the azeotropic distillation of nitric acid and water?

What temperature will form an azeotrope for a mixture of chloroform and acetone at 1 atm?

450 lbmol/hr of mixture of 60% mol benzene and 40% mol toluene is to be separated at 1 atm into a liquid distillate and a liquid bottoms product of 95% and 5% mol, respectively. The feed enters the column with a molar percent vaporization equal to the distillate-to-feed ratio.

What is the slope of the q-line?

450 lbmol/hr of mixture of 60% mol benzene and 40% mol toluene is to be separated at 1 atm into a liquid distillate and a liquid bottoms product of 95% and 5% mol, respectively. The feed enters the column with a molar percent vaporization equal to the distillate-to-feed ratio.

.If R/R_min = 1.3, what is the slope of the rectifying-section operating line?

450 lbmol/hr of mixture of 60% mol benzene and 40% mol toluene is to be separated at 1 atm into a liquid distillate and a liquid bottoms product of 95% and 5% mol, respectively. The feed enters the column with a molar percent vaporization equal to the distillate-to-feed ratio

Determine the number of equilibrium stages to achieve the desired separation.