This is a sort of assignment of my subject Refinery Engineering, i have a presentation on it, i hope u guys like it and enjoy reading it, may be it can help somebody learning alkylation topic :)

1. Alkylation
By: Abbas Ali Zulfiqar
Roll No: BENG/F10/0101
Refinery Engineering By: Sir Atif

2. Introduction (Alkylation)
 Alkylation, first commercialized in 1938,
experienced tremendous growth during the
1940’s as a result of the demand for high
octane aviation fuel during World War II.
 During the mid 1950’s refiners’ interest in alkylation
shifted from the production of aviation fuel to the use of
alkylate as a blending component in automotive motor
fuel.
 The alkylation reaction combines isobutane with light
olefins in the presence of a strong acid catalyst.

3. Introduction (Alkylation)
 Although alkylation can take place at high temperatures
without catalyst
 the only processes of commercial importance today
operate at low to moderate temperatures using either
sulfuric or hydrofluoric acid catalysts.
 The reactions occurring in the alkylation process are
complex and produce an alkylate product that has a wide
boiling range.

4. Alkylation (Definition)
 Alkylation is the transfer of an alkyl group from one
molecule to another.
 The alkyl group may be transferred as an alkyl
carbocation, a free radical, a carbanion or a carbene
(or their equivalents).

5. Main Types Of Alkylation Process
1. Sulfuric Acid Alkylation Process
2. Hydrofluoric Acid Alkylation Process
 Phillips Process
 UOP Process
Phillips and UOP are the two common types of hydrofluoric acid
alkylation processes in use.

6. Industrial Process of Alkylation
 More specifically, the main sections of a STRATCO
Effluent Refrigerated Sulfuric Acid Alkylation
Process will be discussed. A sulfuric acid alkylation
unit can be divided into five major sections as seen on
the following page (Figure 1).

7. Block Flow Diagram of a STRATCO®
Effluent Refrigerated
Sulfuric Acid Alkylation Unit

8. Description
Each section is described below
1. Reaction Section: The reacting hydrocarbons are
brought into contact with sulfuric acid catalyst under
controlled conditions.
2. Refrigeration Section: The heat of reaction is
removed and light hydrocarbons are purged from the
unit.

9. Description (Cont…)
3. Effluent Treating Section: The free acid, alkyl sulfates
and di-alkyl sulfates are removed from the net effluent
stream to avoid downstream corrosion and fouling.
4. Fractionation Section: Isobutane is recovered for
recycle to the reaction section and remaining
hydrocarbons are separated into the desired products.
5. Blowdown Section: Spent acid is degassed, waste
water pH is adjusted and acid vent streams are
neutralized before being sent off-site.

10. Hydrofluoric Acid Alkylation Process
The second main catalyst option is hydrofluoric acid. In
typical alkylation plants, rates of consumption for acid are
much lower than for sulfuric acid. These plants also
produce
alkylate with better octane rating than do sulfuric plants.
However, due to its hazardous nature, HF acid is produced
at very few locations and transportation must be managed
rigorously.

11. Application
OIL REFINING:
Alkylation of alkenes (shown here is propene) by isobutane is a major process in refineries. It is catalysed
by strong acids such as HF and sulfuric acid.
 In a standard oil refinery process, isobutane is alkylated with
low-molecular-weight alkenes (primarily a mixture of propene
and butene) in the presence of a strong acid catalyst, either
sulfuric acid or hydrofluoric acid.

12. Application (Cont…)
 In an oil refinery it is referred to as a sulfuric acid
alkylation unit (SAAU) or a hydrofluoric alkylation unit,
(HFAU).
 The reaction is carried out at mild temperatures (0 and
30 °C) in a two-phase reaction.
 Because the reaction is exothermic, cooling is needed:
SAAU plants require lower temperatures so the cooling
medium needs to be chilled,
 for HFAU normal refinery cooling water will suffice.

13. Purpose of Alkylation
 The purpose of alkylation is to increase the production of
aviation fuel to the use of alkylate as a blending
component in automotive motor fuel, as a antiknock
agent to increase fuel’s octane number.
 The product is called alkylate and is composed of a
mixture of high-octane, branched-
chain paraffinic hydrocarbons (mostly
iso-heptane and iso-octane)
 Alkylate is a premium gasoline blending stock because it
has exceptional antiknock properties and is clean burning.

14. Health and safety considerations
 Sulphuric acid and hydrofluoric acid are dangerous
chemicals, and care during delivery and unloading of acid
is essential.
 There is a need to maintain sulphuric acid
concentrations of 85 to 95% for good operation and to
minimize corrosion.
 To prevent corrosion from hydrofluoric acid, acid
concentrations inside the process unit must be
maintained above 65% and moisture below 4%
 Vents can be routed to soda ash scrubbers to neutralize
hydrogen fluoride gas or hydrofluoric acid vapours
before release.

15. Health and safety considerations
(Cont…)
 There is a potential for serious hazardous and toxic exposures
should leaks, spills or releases occur.
 Direct contact with sulphuric or hydrofluoric acid will cause
severe skin and eye damage, and inhalation of acid mists or
hydrocarbon vapours containing acid will cause severe
irritation and damage to the respiratory system.
 Safe work practices and appropriate skin and respiratory
personal protective equipment are needed where potential
exposures to hydrofluoric and sulphuric acids during normal
operations exist, such as reading gauges, inspecting and
process sampling, as well as during emergency response,
maintenance and turnaround activities

16. The End