Table of Contents
What does height of transfer unit mean?
It relates the height of the column or packing that gives the same change in liquid or gas composition as one transfer unit. The height of a transfer unit is therefore calculated from the ratio of the height equivalent to a theoretical plate (HETP) to the number of transfer units (NTU)…. …
What does higher mass transfer coefficient mean?
As we know that as velocity increases, mass transfer coefficient increases because of fresh fluid elements coming into the mass transfer interface. If fresh fluid elements come to the interface, then mass transfer driving force will be higher and consequently molar flux will also be higher.
What is mass transfer coefficient What is the unit of mass transfer coefficient and heat transfer coefficient?
Mass transfer coefficient units ‘ is expressed in units of moles per unit of volume, but in some cases the driving force is represented by other measures of concentration with different units.
What is the physical significance of NTU?
NTU means number of transfer units. It signifies that the heat transfer capacity of a given heat exchanger. NTU signifies how much number of units of heat, the given heat exchanger is capable of transferring from one fluid to other.
What is KY in mass transfer?
(3.2-5) In this expression, ky and kx are the individual mass transfer coefficients based on the gas and. the liquid phase, respectively. The mole fractions yAi, yA, xA, and xAi are defined in Figure. 3.2-1.
How do you increase mass transfer coefficient?
In that case you can increase mass transfer by increasing flow rate of the liquid (leads to elevated mass transfer coefficients), using more liquid (keeps the difference in chemical potential of the solute in the solid and the liquid at a higher level -> increased driving force) or exchange the liquid completely from …
What is K type mass transfer coefficient?
k is defined as the mass transfer coefficient. in this situation, based on a concentration driving force. It is possible to define a mass transfer coefficient in the same situation using a mole fraction driving force.
What is mass transfer area coefficient?
The dialyzer mass transfer-area coefficient (KoA) for area is an important determinant of urea removal during hemodialysis and is considered to be constant for a given dialyzer.
What is difference between NTU and lmtd method?
The LMTD method is convenient for determining the overall heat transfer coefficient based on the measured inlet and outlet fluid temperatures. The ε-NTU method is more convenient for prediction of the outlet fluid temperatures if the heat transfer coefficient and the inlet temperatures are known.
What is y * in mass transfer?
yA* is the concentration (mole fraction) in vapor phase that is in equilibrium with xAL. Driving force for mass transfer: ( yAG – yA* ) in the gas phase (as indicated by line PC) and ( xA* – xAL ) in the liquid phase (line PD).