Recent questions tagged mass-transfer

The correct expression for the Colburn $j$-factor for mass transfer that relates Sherwood number ($Sh$), Reynolds number ($Re$) and Schmidt number ($Sc$) is$\frac{Sh}{\le...

In the drying of non-dissolving solids at constant drying conditions, the internal movement of moisture in the solid has a dominant effect on the drying rate duringthe in...

$100$ $kg$ of a feed containing $50$ $wt.\%$ of a solute $C$ is contacted with $80$ $kg$ of a solvent containing $0.5$ $wt.\%$ of $C$ is a mixer-settler unit. From the op...

Two spherical camphor particles of radii $20$ $cm$ and $5$ $cm$ far away from each other, are undergiong sublimation in a stream of air. The mass transfer coefficient is ...

A countercurrent absorption tower is designed to remove $95\%$ of component $A$ from an incoming binary gas mixture using pure solvent $B$. The mole ratio of $A$ in the i...

Which of the following conditions are valid at the plait point?Density difference between the extract and raffinate phases is zeroInterfacial tension between the extract...

The composition of vapour entering a tray in a distillation column is $0.47$. The average composition of the vapour leaving the tray is $0.53$. The equilibrium compositio...

Consider steady state mass transfer of a solute $A$ from a gas phase to a liquid phase. The gas phase bilk and interface mole fractions are $y_{A,G}$ and $y_{A,i}$, respe...

Consider a first order catalytic reaction in a porous catalyst pellet.Given $R$ – characteristics length of the pellet; $D_{e}$ – effective diffusivity; $k_{c}$ – mass tr...

A sparingly soluble gas (solute) is in equilibrium with a solvent at $10$ bar. The mole fraction of the solvent in the gas phase is $0.01$. At the operating temperature a...

The vapour phase composition and relative volatilities (with respect to $n$-propane) on an ideal tray of a distillation column are$$\begin{array}{clcIcIcI|cI|c}\hline&\te...

The Sherwood number $(Sh_{L})$ correlation for laminar flow over a flat plate of length $L$ is given by$$Sh_{L}=0.664\:Re_{L}^{-0.5}\:Sc^{1/3}$$where $Re_{L}$ and $Sc$ re...

In a batch absorption process, $5\:g$ of fresh absorbent is used to treat $1$ liter of an aqueous phenol solution. The initial phenol concentration is $100\:mg$/liter. Th...

For what value of Lewis number, the wet-bulb temperature and adiabatic saturation temperature are nearly equal?$0.33$$0.5$$1$$2$

A binary distillation column is to be designed using McCabe Thiele method. The distillate contains $90$ mol$\%$ of the more volatile component. The point of intersection ...

Solute $C$ is extracted in a batch process from its homogenous solution of $A$ and $C$, using solvent $B$. The combined composition of the feed and the extracting solvent...

For a binary mixture of components $A$ and $B$, $N_{A}$ and $N_{B}$ denote the total molar fluxes of components $A$ and $B$, respectively. $J_{A}$ and $J_{B}$ are the cor...

A spherical naphthalene ball of $2\:mm$ diameter is subliming very slowly in stagnant air at $25^{\circ}C$. The change in the size of the ball during the sublimation can ...

Identify the $WRONG$ statement amongst the following:Steam distillation is used for mixtures that are immiscible with water.Vacuum distillation is used for mixtures that ...

A multi-stage, counter-current liquid-liquid extractor is used to separate solute $C$ from a binary mixture $(F)$ of $A$ and $C$ using solvent $B$. Pure solvent $B$ is re...

Consider a steady state mass transfer process between well-mixed liquid and vapour phases of a binary mixture comprising of components $A$ and $B$. The mole fractions of ...

Adsorption on activated carbon is to be used for reducing phenol concentration in wastewater from $0.04$ mol/$1$ to $0.008$ mol/$1$. The adsorption isotherm at the operat...

A binary distillation column is operating with a mixed feed containing $20$ mol$\%$ vapour. If the feed quality is changed to $80$ mol$\%$ vapour, the change is the slope...

A wet solid of $100\:kg$ is dried from a moisture content of $40\:wt\%$ to $10\:wt\%$. The critical moisture content is $15\:wt\%$ and the equilibrium moisture content is...

A spherical ball of benzoic acid (diameter=$1.5\:cm$) is submerged in a pool of still water. The solubility and diffusively of benzoic acid in water are $0.03$ $k$mol/$m^...

A spherical storage vessel is quarter-filled with toluene. The diameter of the vent at the top of the vessel is $1/20^{th}$ of the diameter of the vessel. Under the stead...

Packed towers are preferred for gas-liquid mass transfer operation with foaming liquids becausein packed towers, high liquid to gas ratio are best handledin packed towers...

Which $ONE$ of the following statements is $CORRECT$ for the surface renewal theory?Mass transfer takes place at steady stateMass transfer takes place at unsteady stateCo...

Assuming the mass transfer coefficient in the gas and the liquid phases are comparable, the absorption of $CO_{2}$ from reformers gas $(CO_{2}+H_{2})$ into an aqueous sol...

A study was conducted in which water was pumped through cylindrical pipes made of a sparingly soluble solid. For a given pipe and certain flow conditions, the mass transf...

A wet is dried over a long period of time by unsaturated air of nonzero constant relative humidity. The moisture content eventually attained by the solid is termed as the...

The packing of an existing absorption tower is replaced with a new type of packing. The height of the packing and the inlet conditions are maintained the same as before. ...

A binary distillation column is designed by McCabe-Thiele method to get a distillate mole fraction of $0.9$. The enriching section operating line has an intercept with $y...

It is decided to extract $A$ from a feed containing $20$ mol$\%$ $A$ and $80$ mol$\%$ $B$ in two ideal cross-current stages as shown below, using equal amount of pure sol...

According to the surface renewal theory, the unit of fractional rate of surface renewal ism$^{2}$ s$^{-2}$m$^{2}$ s$^{-1}$m s$^{-1}$$s^{-1}$

For absorption of $H_{2}S$ from a mixture with hydrocarbon vapour into an aqueous alkanolamine solution, the liquid phase mass transfer resistance issignificantly higher ...

Two packed towers are designed for the same mass velocity of the gas. The first has liquid and gas flow rates of $30\:kg/s$ and $1.2\:kg/s$, respectively, while the corre...