List of top Chemical, Thermal and Polymer Engineering Questions on Mass Transfer

A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day when it is concentrating from 10% to 35% solids. The water evaporated in kg per day is:
Match LIST-I with LIST-II and select the correct answer using the codes given below the lists.\[\begin{array}{|c|c|} \hline \textbf{LIST-I} & \textbf{LIST-II} \\ \hline \text{A. Rotary atomizer} & \text{1. Kinetic energy} \\ \hline \text{B. Relative volatility} & \text{2. Centrifugal energy} \\ \hline \text{C. Pneumatic nozzle} & \text{3. Distillation} \\ \hline \text{D. Selectivity} & \text{4. Liquid-liquid extraction} \\ \hline \end{array}\] Choose the correct answer from the options given below:
The McCabe-Thiele method used to find the number of theoretical stages required in a distillation operation is based on the assumption(s) that:
Steady state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapour-gas mixture is:
For economical operation in gas absorption, the operating line approximately:
Which of the following is used as an 'entrainer' in the separation of acetic acid-water mixture by distillation?

A wet solid of 100 kg containing 30 wt% moisture is to be dried to 2 wt% moisture in a tray dryer. The critical moisture content is 10 wt% and the equilibrium moisture content is 1 wt%. The drying rate during the constant rate period is 10 kg/(h m²). The drying curve in the falling rate period is linear. If the drying area is 5 m², the time required for drying ___________ h (rounded off to 1 decimal place).

Solute \(A\) is absorbed from a gas into water in a packed bed operating at steady state. The absorber operating pressure and temperature are 1 atm and 300 K, respectively. At the gas-liquid interface, \(y_i = 1.5 x_i\), 
where \(y_i\) and \(x_i\) are the interfacial gas and liquid mole fractions of \(A\), respectively. At a particular location in the absorber, the mole fractions of \(A\) in the bulk gas and in the bulk water are 0.02 and 0.002, respectively. If the ratio of the local individual mass transfer coefficients for the transport of \(A\) on the gas-side (\(k_y\)) to that on the water-side (\(k_x\)), \(\frac{k_y}{k_x} = 2\), then \(y_i\) equals _________ (rounded off to 3 decimal places).

If \( k \) is the mass transfer coefficient and \( D_v \) is the molecular diffusivity, which one of the following statements is NOT CORRECT with respect to mass transfer theories?
In the McCabe-Thiele diagram for binary distillation, vertical feed line represents ......., and horizontal feed line represents ............ feed.
Sugar is leached from sugar beets with:
HETP is numerically equal to HTU only when the operating line:
Flash distillation is used at a large scale in:
In the absorption of a solute gas from a mixture containing inerts in a solvent, it has been observed that the overall gas transfer coefficient is nearly equal to the individual gas film transfer coefficient. It may therefore be concluded that:
In a small column, local efficiency is equal to Murphree efficiency, and in a large column, local efficiency is:
Which of the following is a continuous filter?