Recent activity in Mass Transfer

The flooding velocity curves for two different structured packings are shown in the figure. The ratio of mass velocities of liquid $\left(G_{x}\right)$ to that of the gas...

A gas stream with $2.01 \mathrm{~mol} \%$ ammonia is to be scrubbed in a counter-current isothermal packed bed absorber using pure water to reduce its concentration to $0...

A continuous distillation column is used to separate an equimolar mixture of diethylamine (DEA) and methanol. The feed enters the column as saturated liquid at a flow rat...

A volatile organic compound $\text{(VOC)}$ is to be adsorbed from air onto a bed of activated carbon. The equilibrium capacity of activated carbon at the feed conditions ...

 Vapor pressure of water at various temperature is given in the table.\[\begin{array}{|l|c|c|c|c|c|}\hline\text{Temperature (in K)} & 284 & 289 & 294 & 299 & 310 \\\hline...

$K$ value is defined as the ratio of mole fraction of a component in the vapor phase to that in the liquid phase. The $K$ values of propane and iso-butane at $293$ $K$ ar...

Consider a non-reactive binary mixture of two ideal gases $\text{A}$ and $\text{B}$ in an isothermal horizontal closed tube. Due to the concentration difference at the tw...

A binary mixture of butane and butadiene is to be separated in an extractive distillation using furfural. Furfural lowers the activity of butadiene more than it does for ...

A wet solid of $100 \:\textsf{kg}$ containing $30 \: \mathrm{wt} \%$ moisture is to be dried to $2 \: \mathrm{wt} \%$ moisture in a tray dryer. The critical moisture cont...

Solute $A$ is absorbed from a gas into water in a packed bed operating at steady state. The absorber operating pressure and temperature are $1 \: \mathrm{atm}$ and $300 \...

Gas containing $0.8\: \mathrm{~mol} \%$ component $\text{A}$ is to be scrubbed with pure water in a packed bed column to reduce the concentration of $\text{A}$ to $0.1 \...

A binary $\text{AB}$ liquid mixture containing $30 \: \mathrm{~mol} \% \: \text{A}$ is subjected to differential (Rayleigh) distillation at atmospheric pressure in order ...

Consider moist air with absolute humidity of $0.02 \: \mathrm{(kg \: moisture)} / \mathrm{(kg dry air)}$ at $1$ bar pressure. The vapour pressure of water is given by the...

​​​​$500 \: \mathrm{mg}$ of a dry adsorbent is added to a beaker containing $100 \: \mathrm{mL}$ solution of concentration $100 \: \mathrm{mg \: phenol/ (L \: solution)}$...

Oil is extracted from mustard seeds having $20 \: \mathrm{wt} \%$ oil and $80 \: \mathrm{wt} \%$ solids, using hexane as a solvent. After extraction, the hexane-free resi...

​​​​​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 ...

​​​​​A homogeneous azeotropic distillation process separates an azeotropic $AB$ binary feed using a heavy entrainer, $E$, as shown in the figure. The loss of $E$ in the t...

Consider a vapour-liquid mixture of components $A$ and $B$ that obeys Raoult's law. The vapour pressure of $A$ is half that of $B$. The vapour phase concentrations of $A$...

​​​​​Consider the steady, uni-directional diffusion of a binary mixture of $A$ and $B$ across a vertical slab of dimensions $0.2 \mathrm{~m} \times 0.1 \mathrm{~m} \times...

Which one of the given statements is correct with reference to gas-liquid contactors for mass transfer applications?A tray tower is more suitable for foaming systems than...

​​​Alumina particles with an initial moisture content of $5 \mathrm{~kg}$ per $\mathrm{kg}$ dry solid are dried in a batch dryer. For the first two hours, the measured dr...

​​​​​A simple distillation column separates a binary mixture of $A$ and $B$. The relative volatility of $A$ with respect to $B$ is $2$. The steady-state composition of $A...

​​​​​Sulfur dioxide $\left(\mathrm{SO}_{2}\right)$ gas diffuses through a stagnant air-film of thickness $2 \mathrm{~mm}$ at 1 bar and $30^{\circ} \mathrm{C}$. The diffus...

​​​​​​A gas stream containing $95 \mathrm{~mol} \% \mathrm{CO}_{2}$ and $5 \mathrm{~mol} \%$ ethanol is to be scrubbed with pure water in a counter-current, isothermal ab...

Consider a tray-column of diameter $120 \mathrm{~cm}$. Each downcomer has a cross-sectional area of $575 \mathrm{~cm}^{2}$. For a tray, the percentage column cross-sectio...

A packed distillation column, with vapor having an average molecular weight of $45 \mathrm{~kg} \cdot \mathrm{kmol}^{-1}$, density of $2 \mathrm{~kg} \cdot \mathrm{m}^{-3...

In a binary gas-liquid system, $N_{A, E M D}$ is the molar flux of a gas $A$ for equimolar counter diffusion with a liquid $B . N_{A, U M D}$ is the molar flux of $A$ for...

A liquid $\boldsymbol{L}$ containing a dissolved gas $\boldsymbol{S}$ is stripped in a countercurrent operation using a pure carrier gas $\boldsymbol{V}$. The liquid phas...

Water in a container at $290 \mathrm{~K}$ is exposed to air containing $3 \% ~ \mathrm{CO}_2$ by volume. Air behaves like an ideal gas and is maintained at $100 ~ \mathrm...

Which one of the following represents the $\text{CORRECT}$ effects of concentration polarization in a reverse osmosis process?Reduced water flux and reduced solute reject...

Partially saturated air at $1 \; \mathrm{bar}$ and $50^{\circ} \mathrm{C}$ is contacted with water in an adiabatic saturator. The air is cooled and humidified to saturati...

A simple distillation column is designed to separate an ideal binary mixture to specified distillate and bottoms purities at a given column pressure. It $RR_{\text{min}}$...

Consider two stationary spherical pure water droplets of diameters $d_{1}$ and $2d_{1}$. $CO_{2}$ diffuses into the droplets from the surroundings. If the rate of diffusi...

Consider steady-state diffusion in a binary $\text{A-B}$ liquid at constant temperature and pressure. The mole-fraction of $A$ at two different locations is $0.8$ and $0....

Consider interphase mass transfer of a species $S$ between two immiscible liquids $A$ and $B$. The interfacial mass transfer coefficient ot $S$ in liquid $A$ is twice of ...

A wet solid containing $20\%$ $\text{(w/w)}$ moisture (based on mass of bone-dry solid) is dried in a tray-dryer. The critical moisture content of the solid is $10\%$ $\t...

The dry-bulb temperature of air in a room is $30^{\circ}C$. The Antoine equation for wateris given as $$\text{ln} P^{sat} = 12.00 -\frac{4000}{T - 40}$$ where $T$ is the ...

An equimolar binary mixture is to be separated in a simple tray-distillation column. The feed rate is $50\text{ kmol min}^{-1}$ . The mole fractions of the more volatile ...