Vacuum distillation presentation

1. Role of
Vacuum
distillatio
n in
refineryPRESENTED BY:
JAWALGE JAY (11920039)
RUPALI KADAM (11920081)
KARTHIK IYER (11810069)
PAYAL KHANDAGALE (11920014)
ARJUN PHAD (11920021)

2. What is distillation?
• A process of separating the component substances
from a liquid mixture by selective evaporation and
condensation.
• Undergoes either complete separation (nearly pure
components) or partial separation
• It’s a physical separation process and not a chemical
reaction.

3. Fig. 1, Crude oil refining PFD, Ref. Britannica.Inc.

4. Vacuum Distillation
• The pressure maintained is about 25 – 40 mm Hg.
The temperature is kept at around 380° – 420°C.
• Such compounds often undergo thermal
decomposition at the temperatures required for their
distillation at atmospheric pressure.
• The boiling point of a compound is lowered
substantially by reducing the applied pressure.

5. Working
Fig. 2, Vacuum distillation unit, Ref. EnggCyclopedia.com

6. Continued…
• Heavies from the atmospheric distillation column are
heated to approximately 400˚C in a fired heater and
fed to the vacuum distillation column where they are
fractionated into light gas oil, heavy gas oil and
vacuum reside
• The distillation column is under a vacuum, or
significantly less than atmospheric pressure of 760
mmHg

7. Continued…
• In distilling the crude oil, it is important not to subject
the crude oil to temperatures above 370 to 380°C
because the high molecular weight components in the
crude oil will undergo thermal cracking and form
petroleum coke
• The vacuum distillation column internals must
provide good vapor-liquid contact
• Ensure to maintain a very low pressure increase from
the column top to the column bottom

8. Continued…
• Superheated steam is injected with the feed and in the
tower bottom to reduce hydrocarbon partial pressure
to 10 mm of mercury or less
• Lower partial pressure of the hydrocarbons makes it
even more easier for them to be vaporized, thus
consuming less heat energy for the process
• At low pressures, the boiling point of the ADU
bottoms is low enough that lighter products can
vaporize without cracking, or degrading the oil

9. Continued…
• A typical first-phase vacuum tower may produce gas
oils, lubricating oil base stocks, and heavy residual
for propane de-asphalting
• A second-phase tower operating at lower vacuum
may distill surplus residuum from the atmospheric
tower, which is not used for lube-stock processing,
and surplus residuum from the first vacuum tower not
used for de-asphalting
• Vacuum towers are typically used to separate catalytic
cracking feedstock from surplus residuum

10. Continued…
Light vacuum gas Oil is
sent to a hydrotreater and
then to a 'catalytic cracking'
unit to obtain smaller chain
hydrocarbons
Heavy vacuum gas oil is
also sent for cracking
using hydrogen in a
'hydrocracking unit' to
produce smaller chain
hydrocarbons

11. Continued…
• Refinery vacuum columns often use distillation trays
only when withdrawing products from the side of the
column
• The remainder of the column uses packing material
for the vapor-liquid contacting because such packing
has a lower pressure drop than distillation trays
• This packing material can be either structured sheet
metal or randomly dumped packing such as Raschig
rings

12. Laboratory-scale applications
Rotary evaporation
• Used to remove bulk
solvents from the liquid
being distilled
• Used by environmental
regulatory agencies for
determining the amount
of solvents in paint,
coatings and inks
Fig. 3, Distillation setup, Ref. EnggCyclopedia.com

13. Continued…
• The rotary evaporator rotates the distillation flask to
enhance the distillation.
• Rotating the flask throws up liquid on the walls of the
flask and thus increases the surface area for
evaporation.
• Heat is often applied to the rotating distillation flask
by partially immersing it in a heated bath of water or
oil.
• The vacuum in such systems is generated by a water
aspirator or a vacuum pump of some type.

14. Industrial applications
• Vacuum distillation columns used in oil refineries
have
Diameters
ranging up to
about 14 meters
(46 feet),
Heights ranging
up to about 50
meters (164
feet),
Feed rates
ranging up to
about 25,400
cubic meters per
day (160,000
barrels per day).
10 to 40 mmHg
of absolute
pressure increases
the volume of
vapor formed per
volume of liquid
distilled.

15. Continued…
Vacuum distillation is a part of the refining process
that helps to produce petroleum products out of the
heavier oils leftover from atmospheric distillation.
The end product of Atmospheric distillation, called
bottoms, remain at the bottom of the ADU.
To increase the production of high-value petroleum
products, these bottoms are run through a vacuum
distillation column to further refine them.

16. Case study
Advanced purification of petroleum refinery
wastewater by catalytic vacuum distillation
• Why is there a need to treat this waste water?
• The hazardous chemicals present in it
• New technologies
• Environmental hazards which in tend lead to these
technologies to not be viable/implemented

17. Continued…
• A solution indeed(CVD)-catalytic Vacuum distillation
• RCOD = c0 – ct/c0(what is cod) and how to calculate
• × 100%
• Experimental setup
• Results

18. Continued…
Fig. 4, Vacuum Distillation unit , Ref. Research paper

19. Vacuum distillation is used for
• Liquids to be distilled that have high atmospheric
boiling points.
• Liquids that chemically change at temperatures near
their atmospheric boiling points.
• To remove solvents from the mixture without
damaging the product.

20. Faster processing time
Effective distillation while
keeping the process under the
maximum temperature of the
distillation unit’s heater
Effective processing of higher
boiling point solvents without
igniting them or causing
thermal breakdown
Advantages of Vacuum Distillation

21. Vacuum Distillation Unit
Fig. 5, Vacuum Distillation unit , Ref. EnggCyclopedia.com

22. References
1. http://www.enggcyclopedia.com/2012/01/vacuum-
distillation-unit/
2. http://www.eia.gov/todayinenergy/detail.php?id=913
0
3. http://www.chem.ucla.edu/~bacher/Specialtopics/va
cuum%20distillation.html
4. http://blog.digivac.com/distillation-low-medium-

23. Q & A

24. Thank You