Chapter 1 PROCESS DESCRIPTION

In this process Sodium Dodecyl Benzene Sulfonate (C12H25C6H4SO3Na) is

manufactured by the reaction of dodecene with benzene in presence of

aluminium chloride catalyst at temperature 46°C and pressure 1 atm. Main

reaction involved in this process are as follows

Alkylation:

AlCl3
C6H6 (l) + C12H24 (l) C18H30 (l)
Dodecyl benzene

Sulfonation:

C6H5.C12H25 + H2SO4 C12H25.C6H4.SO3H + H2O

Dodecyl benzene
Sulfonic acid

Neutralizations:

C12H25.C6H4.SO3H + NaOH C12H25.C6H4.SO3Na + H2O

Sodium dodecyl
Benzene sulfonate

The alkylation reaction takes place in fabricated low carbon steel jacketed

and agitated glass lined reactor. The reaction is highly exothermic and heat

of reaction is removed by cooling the water. The feed temperature of

reaction is 46°C and reactor outlet stream is at 46°C which is maintained by

the flow of cool water.

Fresh feed benzene comes at 27°C from benzene storage tank to benzene

receiver tank V-1. Similarly fresh feed dodecene comes at 38°C from

dodecene storage tank to dodecene receiver tank V-2. Both are pumped to

alkylator (R-1) at 46°C and AlCl3 is also introduced to alkylator. Outlet of

alkylator consists of unreacted dodecene, dodecyl benzene and heavy

ends goes to alkylator settler (S-1) where AlCl3 sludge removed.

Unconverted benzene and dodecene and dodecyl benzene (DB) feed

preheater from 46°C by means of Stream.

Benzene tower (C-1) operated at 1 atm. In this tower Benzene is recovered

as distillate after condensation in Benzene tower condenser O/H (E-2).

From Benzene reflux drum (V-10) Benzene goes to Benzene cooler (E-11)

where it is cools from 83.33°C to 50°C and goes to Benzene receiver tank

(V-1). Bottom heat is provided by steam in Benzene tower reboiler (E-3).

Bottom products are dodecene and DB and heavy ends.

Bottom products of Benzene tower (C-1) cool in dodecene tower feed

cooler (E-4) from 265°C to 247°C and entered to dodecene tower (C-2)

which is operated at 280mm Hg. In this tower dodecene is recovered as

distillate after condensation in dodecene tower O/H condenser (E-5). From

dodecene reflux drum (V-11) dodecene goes to dodecene cooler (E-12)

where it is cools from 175°C to 120°C and goes to dodecene receiver tank

(V-2). Bottom heat is provided by steam in dodecene tower reboiler (E-

6).Bottom products are DB and heavy ends.

Bottom products of dodecene tower (C-2) cool in DB tower feed cooler (E-

7) from 283 to 254°C and entered to DB tower (C-3) which is operated at

40mm Hg. In this tower DB is recovered as distillate after condensation in

DB tower O/H condenser (E-8). Bottom heat is provided by steam in DB

Tower reboiler (E-9). Bottom products are heavy end which is sent to ETP.

Top product of DB tower (C-3) cool in sulfonator feed cooler (E-10) from

216.5 to 46C and entered to sulfonator (R-2). 20% oleum from oleum tank

(V-5) is also entered to sulfonator (R-2) where sulfonator reaction takes

place which is highly exothermic reaction and heat of reaction removed by

the cool water which flows in jacket. The sulfonator (R-2) outlet goes to

sulfonator settler(S-2) where water is added from dilution water storage

tank. The unreacted H2SO4 converted into spent acid of 78% H2SO4, which

is sent to spent acid storage tank from where it is transported for further

usages.

From sulfonator settler (S-2) DBS, H2SO4 and water entered in neutralizer

(R-3). 20% NaOH from NaOH storage tank is also entered in Neutralizer at
46.1°C. In Neutralizer (R-3), Neutralization reaction takes place which is

highly exothermic reaction and heat of reaction removed by the flow of cool

water in reactor jacket.

The outlet of Neutralizer goes to spray dryer D-1 which is supplied by the

furnace. The final outlet of drier is SDBS which is then cooled in product

cooler and conveyed for bagging or for product side.

Spray dryer D-1 outlet gases contains water vapour and product lines

which is scrubbed in a venture scrubber by means of scrubber liquor and

collected in scrubber effluent tank. Similarly product cooler duet is sucked

by cooler fan and sent to venture scrubber for scrubbing by scrubber liquor

and collected in second effluent tank. Both scrubber effluent tanks are

connected through a launder. Scrubber liquor pump takes suction from the

tank and its discharge to both venture scrubber and a part of it sent back to

product blending tank for maintaining concentration of scrubber effluent

tank service water is provided.

Chapter 2 SUMMARIES OF RAW MATERIALS

a) Dodecene: Liquid Dodecene is limiting reactant in

alkylation process; it is used for alkylation of benzene.
Dodecene (99% Pure) is supplied by utility to Dodecene
receiver where recycle Dodecene is mixed and then fed
to alkylator.

b) Benzene: Liquid Benzene is the main raw material of

the alkylation process. Benzene (99% Pure) is supplied
from utility to Benzene receiver where recycle benzene
from benzene recovery section is mixed and then fed to
alkylator

c) Oleum: 20% Oleum (20% SO3 w/w) is used for

sulfonation of dodecyl benzene in sulfonator. Oleum is
supplied by utility from its storage tank to plant day
tank. Oleum is used in place of 98% Sulfuric acid as it
has high affinity to water which is formed during reaction
so that specific consumption of water is decreased for
acid dilution.

d) Caustic Soda: Caustic Soda (20% NaOH w/w) is used for

Neutralization of dodecyl benzene sulfuric acid to form
its sodium salt. 20% NaOH is supplied by utility from its
main storage tank to plant day tank.
e) Water: Water is used for dilution of unreacted Oleum to
form 78% conc. Sulphuric acid. Ground water is used for
this purpose Ground water from bore wells at utility is
stored in raw-water storage tanks made of RCC. From
there it is pumped to Dilution water storage day tank.
 f) Catalyst: Powdered anhydrous Aluminium chloride
(AlCl3) is used for alkylation as Friedel-Craft catalyst.
Anhydrous AlCl3 is stored in air tight drums in store
section. It is used once through in each batch of alkylator
and separated from settler and stored in scrap yard for
disposal.

UTILITIES:

g) M.P.Steam: Plant is dependent on steam which is

supplied by Medium pressure boilers (3.6 MPa or 36 bars,
390 deg C) of utility section in superheated form. Steam
is then saturated by quenching and used in feed
preheaters as well as in reboilers.

h) L.P. Steam: L.P. Steam (0.35 MPa or 3.5 bar, 180 deg
C) is supplied by utility section after pressure reduction
and desuperheating of M.P. Steam. This steam is used
for atomisation of furnace oil in combustion chamber of
dryer as well for flushing of spargers and nozzles,
cleaning etc.

i) Cooling Water: Cooling water is used to carry out

process heats of reactors as well as Coolers and
overhead condensers of distillation columns. It is also
used to cool bearing housings of blowers and pumps. It is
 supplied by cooling towers at utility section at 3.5 bar
and 26°C.

j) Plant Air: Plant Air (6 bar, ambient temp.) is supplied

by utilities for draining of lines, vessel entry as well as for
flushing and cooling purposes.

k) Plant water: Plant water (4.0 bar, ambient temp.) is

supplied by utility from its raw water storage to plant. It
is used for cleaning

l) Drinking water: Drinking water (4 bar, ambient temp.)

is supplied by utility after filtration and chlorination of
raw water. It is used for drinking as well as for eye wash
and showers at different locations of plant.

m) Power (Electricity): Power is supplied by state

electricity board at 3 phases, 3.3 KV and 50Hz (H.T.)
which is step-down in Sub stations at utility to feeders of
415V (for L.T. motor control) and 240 V for plant lighting
and other uses.

Besides this a captive power plant (Diesel Generators) is

also installed to run L.T motors as well as for lighting during
failure of electricity. It is necessary to safe shutdown of plant as
well as resuming of plant lighting. Although Captive power plant is
capable to run plant’s all of the L.T.Motors and plant may run up
to Neutralizer.
n) Instrument Air: Instrument air (7.0 bar, ambient temp.)
is supplied by utility from its Instrument air drying unit
(Alumina based, No loss type). It is used to operate
instruments and control valves.

o) Fire Fighting Water: Fire fighting water (7.0 bar,

ambient temp.) is supplied by utility from its pump
house. Fire water pump takes suction from raw water
storage and maintained fire hydrant header to
aforementioned pressure. From this header, fire hoses
are provided at different locations of the plant.