1. MOBASHSHIR RASHID
B.TECH IV YEAR
CSJMA14001390207
CATALYTIC ALKYLATION

2. CONTENT
INTRODUCTION
H2SO4 ALKYLATION PROCESS
 TIME TANK PROCESS
 EFFLUENT REFERIGERATION PROCESS
 CASCADE AUTOREFERIGERATION PROCESS
HF ALKYLATION PROCESS
 PHILIPS PROCESS
 UOP PROCESS
PROCESS VARIABLES
COMPARISON OF H2SO4 AND HF ALKYLATION
PROCESS

3. INTRODUCTION
• Catalytic alkylation process is used in petroleum refineries to upgrade
light olefins and isobutane into a highly branched Paraffins.
• The product is called alkylate which is used as a blending component
for making gasolines.
• Alkylate has both excellent stability and high research octane number
(RON) (about 96).
• Alkylate has high heat of combustion per kg and low vapour pressure,
the low vapour pressure of alkylate allows lower cost butane to put into
gasoline.

4. H2SO4 ALKYLATION
PROCESS
H2SO4 alkylation units are based on three
designs
• Time tank process
• Effluent refrigeration process
• Cascade autorefrigeration process

5. • This system includes a heat exchanger or chillers, time tank reactor
and a circulation pump forming a close loop circulation pipe line .
• Circuit time is about 1 to 2 minutes,while the average hydrogen
residence time in the loop (contact time) is about 20 to 30 minutes.
• The isobutane and olefin stream are contacted with H2SO4 in large
uncooled pipe near the centrifugal pump for providing mixing and
emulsification.
• High temperatures are avoided by using high acid to hydrocarbon
ratios.
TIME TANK PROCESS

6. • Emulsion enters the chiller where the heat of reaction is removed
by refrigerant.
• Emulsion is introduced in a time tank reactor where alkylation
reaction occur.
• A continuous stream is taken from the bottom of the reactor and
send to the settler for separation of hydrocarbon and acid phases.
• Hydrocarbon phase is caustic and water treated to remove acid and
esters before entering the separation section,in which the product
mixture is separated in isobutane ,alkylate,n-butane and propane
streams,isobutane being recycled to the reaction section.
•When aviation alkylate is required ,a rerun column is needed to
reduce the end-point of the alkylate.

8. EFFLUENT REFRIGERATION PROCESS
• The circuit time is of the order of 10 seconds.
• The hydrocarbon feed as well as the acid are introduced at the
eye of impeller and both are recycled through the outer shell and
passed through the tube bundle to remove the heat of reaction and
the energy of the impeller
• This system provides a rapid circulation of both reactants and
solid catalyst.
• In this process reactor is a horizontal vessel or contactor with an
impeller in one end and a tube bundle or cooling coils on the other.

9. Horizontal alkylation contactor used in effluent refrigeration
process

10. CASCADE AUTOREFRIGERATION PROCESS
• The reactors are large horizontal drums, provided by 3 to 7 reactor
stages in one end of the reactor,and an acid settler on the other side of
reactors.
• Each stage is partially filled with liquid acid hydrocarbon
suspensions, and a gas mixture is above the liquid.
• Acid and isobutene stream are introduced in first stage while olefin
feed is divided into all stages.
• Unreacted isobutane,alkylate and acid flow from one stage to the
next , and eventually reach the acid settler.

11. • Cooling is carried by equilibrium vaporisation of light hydrocarbons
mainly isobutane at system pressure.
• Olefin feed in each stage is added just above the impeller and mixed
into the emulsion of acid hydrocarbon.
• The upper portion of the emulsion is generally hydrocarbon
continous and has a lower residence time than the acid phase due to
density difference.

13. HF ALKYLATION PROCESS
•The Phillips Process
•This process uses a riser type reactor ,in which hydrocarbon mixture
is
•Introduced through nozzles .
•High velocities are achieved due to pressure drop ,resulting in
emulsions
of liquid HF and liquid hydrocarbons that rise in the uncooled
reactor
•In vertical reactor riser perforated trays provide dispersion of the
hydrocarbon phase from acid phase.
•Recycle HF is continuously leave the bottoms of the settler because
of gravity

14. • Hydrocarbon mixture in the settler which contains
mainly isobutane and alkylate and small amount of
propane ,n butane dissolved HF and isoalkyl flourides is
passed to the
main fractionators.
• The Mixture is into top stream and side stream top stream
is directed to an HF stripper to separate HF and propane.
• All the streams leaving the unit are treated with KOH to
eliminate residual acidity.

16. UOP PROCESS
• Isobutene olefin feed mixture enters the shell of a vertical
reactor heat exchanger.
• HF is introduced at the bottom of the shell.
•Heat of reaction is removed by cooling water in a cooling coil.
•Effluent mixture is directed to the settler.
• Hydrocarbon phase passed through stripper and acid is
recycled back to reactor heat exchanger.

17. • Isobutane is withdrawn as a side stream and recycled to the
reactor
• Isostripper overhead is sent to HF stripper to strip acid
•Overhead of hf stripper is sent to top of the stripper for
recovery of the acid and isobutane and bottom is sent to
depropanizer .
•An internal depropanizer is required between isostripper and
the HF stripper, if amount of propane in C4 fraction is too
high.

19. PROCESS VARIABLES
•Reactor temperature low temp requires higher refrigeration and
investment costs
•Isobutane recycle rate high isobutane recycle rate increases the
investment requirement for the deisobutanizer and increases the operating cost
of tower because of high steam requirement
•Space velocity high space velocity increases the formation of acid sulphates
corrosive to the downstream fractionation facilities
•Spent acid strength low spent acid strength tends to decrease make up
acid requirements ,it increases the risk of acid runaway

20. COMPARISON OF H2SO4 AND HF ALKYLATION
PROCESS
Cost of catalysts is much higher(about 30 percent )than HF
(about 5 percent).
HF is more dangerous when using in alkylation process than H2SO
Olefin
88 -89
91- 92
95.7
97.7
96 -98
HF
91 -
92
93 -
95
87 -
Propylene
Isobutylene
1 butene
2 butene
H2SO4
COMPARISON OF H2SO4 AND HF ALKYLATION
PROCESS
Octane number of alkylate

21. THANK YOU