Synthetic detergents, which
are also known as syndets, were developed to overcome
the difficulties faced while using soap as a cleaning
agent. Soaps when used in hard water precipitate
the calcium and magnesium salts, due to which
it's effectiveness as a cleaning agent deteriorates.
In addition, edible oil &
fats, which could be put to other uses, are used
as raw materials for the manufacture of soaps.
These problems are circumvented in synthetic detergents
that are highly stable in hard water and do not
consume valuable and expensive oil for their manufacture.
Detergent powder falls
into four major groups :
duty detergents (high and low
Light duty detergents
essentially consists of :
(e.g. Sodium sulphate)
Normally active ingredients
used for detergents are linear alkyl benzyl sulphonates.
Free flowing, non
dusty, non caking detergent products
in bead form are produced by Spray
Drying mostly in counter current flow
using pressure nozzle atomization.
Inlet temperatures vary according
to product and upto 400°C inlet
temperatures are used for some detergents.
Hot air from direct fired air heaters
is used for Spray Drying. Exhaust
high efficiency cyclones / bag houses
are used to control emissions and
maximize product recovery are part
of the spray drying plant. RAJ offers
stand alone spray drying plants on
Perfuming & Packing
The dried detergent
powder is pneumatically conveyed from
the Spray Dryer to the product silos
after sieving. Here filtered atmospheric
air is used as the cooling & conveying
media. Dense phase conveying systems
are normally preferred.
The detergent product from the silo
is then blended along with the perfume
in a continuous mixer after which
it is packed.
(Detergents, Soaps, Surface
The free-flowing, non-dusty, non-caking
products in bead form are produced in counter-current
flow dryers with nozzle atomization is the
preferred layout for high-bulk-density detergents.
Feeds are homogenized and fine-filtered
prior to passing to nozzles operating at
high pressure. Hot air from direct-fired
air heaters enters at the base of the cylindrical
part of the tower with slight rotary motion.
The exhaust air is drawn from the top of
the tower. Inlet temperatures vary according
to product. Up to 400°C (750°F)
is used for some detergents, but lower temperatures
are used for fine washing agents. Product
recovery from the drying tower is high (99%).
The fines fraction is usually returned to
feed preparation. Open - cycle dryers are
normally used, Co-current dryers are used
for low - bulk - density detergents.
consist basically of (a) an active ingredient
(b) sodium tripolyphosphate, (c) silicates,
(d) sodium sulphate. Normally the active
ingredients are fatty alcohol sulphates,
primary and secondary alkyl sulphonates
and alkyl aryl sulphonates. Synthetic detergents
are currently based upon linear alkyl benzene
sulphonates. Formulations are with variations
as decided by each company.
Heavy - Duty Detergents
Synthetic detergents are
widely used in cleaning of all types and
operate successfully with hard water. The
coarse powder granules in bead form are
free-flowing, non-dusty and readily dissolve
in water. Shelf-life is excellent, with
no tendency to instability or lumping. The
feed can be formulated batchwise or continuously.
RAJ slurry preparation systems ensures the
right preparation technique which improves
the quality of the final dried detergent
powder. Precise weighing / metering, mixing,
homogenizing and de-aeration take place
before spray drying. As high a solid content
as possible is used (50 - 65%) to give the
optimum powder bulk density and best economic
use of the spray dryer.
The product is dried in a counter-current-flow
drying tower at inlet temperature 350 -
400°C (660 - 750°F). The dried powder
leaves the base of the drying tower and
is transported via a conveyor belt to an
air lift. During passage on the belt, product
dosing is carried out. Dosing materials
can be products that would be damaged during
spray drying, e.g. lauryl alcohol, enzymes.
Bleach alongwith enzymes is also added at
this stage. Perfume is added after the following
Light Duty Detergents
Light - duty detergents
are used less than heavy duty. They find
wide application only in dish washing and
light household cleaning (janitoring). Light
-duty detergents are produced in nozzle
towers with either co-current or counter-current
flow. Choice depends upon required bulk
density. Inlet drying temperatures are also
lower, 250 - 275°C (480 - 530°F).
Detergent Allied Products
RAJ also provides state
of art powder technology for detergent allied
products like Sodium Lauryl Sulphate (SLS),
Alfa Olefin Sulphonate (AOS), Optical Brightening
Agents (OBA), Linear Alkyl Benzyl Sulphonate
(LABSA), Sodium Silicate, Sodium Tri-polyphosphate