Fractional distillation of oil with mass transfer

1. MASS TRANSFER
IT CAN BE DEFINED AS THE TRANSFER OF MASS FROM ONE LOCATION TO ANOTHER ON
THE BASIS OF CHEMICAL POTENTIAL DIFFERENCE.”CHEMICAL POTENTIAL BASICALLY
INCLUDES:-
PRESSURE (DIFFERENCE).
CONCENTRATION /MOLE FRACTION (DIFFERENCE).
PROCESSES OF MASS TRANSFER:-
MASS TRANSFER INCLUDES MANY PROCESSES SOME OF WHICH ARE AS FOLLOWS:-
DISTILLATION, DIFFUSION, CRYSTALLIZATION, EVAPORATION

2. OIL INDUSTRY
OIL INDUSTRY IS A REFINERY FUNCTIONS IN THE FORM OF
FOLLOWING PROCESSES:-
*Distillation
*Catalytic reforming
*Catalytic cracking
*Alkylation
*Isomerization
*Hydrotreating

3. WHEREDOESMASSTRANFEROCCURINOILINDUSTRIES?
When the oil is extracted from the sea or
land, it is in the form of crude oil which
means it can’t be use directly at it’s raw
state, so we use the process of Fractional
Distillation to refine it and get different bi
products in result of it. The Mass Transfer
process occurs in Fractional Distillation.

4. Fractional Distillation
To convert crude oil into useful products we have to separate the
mixture.
We do this by heating it and collecting the fractions that boil over
different ranges of temperatures.
Each fraction is a mixture of hydrocarbons of similar chain length
and therefore similar properties.
The process is called fractional distillation and is done in a
fractionating tower.

5. STEPS
The crude oil is first heated in a furnace
A mixture of liquid and vapor passes into a tower that is cooler at the
top than at the bottom
The vapors pass up until they arrive at a tray that is sufficient. Then they
condense to liquid.
The mixture of liquids that condenses on each tray is piped off.
The shorter chain hydrocarbons condense in the trays nearer to the top
of the tower, where it is cooler, because they have lower boiling points.
The thick residue that collects at the base of the tower is called tar or
bitumen. It can be used for road surfacing but, as supply often exceeds
demand, this fraction is often further processed to give more valuable
products.