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Bromine from
Sea Water
Introduction
Bromine is widely distributed in nature,
but in relatively small proportions. Bromine and bromo-compounds
have wide range of uses in chemical and other uses. It is
used for the manufacture of dye intermediate & dye stuffs,
drugs & pharmaceutical products, photography chemicals,
insecticides, fuming agents, antiknock gasoline, fire retardants,
in textile industry and in oil exploration. It is also used
in controlling microbes and algae in swimming pools.
The bromine available for extraction occurs as bromide in
the ocean, in salt lakes and in brine or saline deposits left
by evaporation of such waters by solar heat. Sea bitterns,
the left over concentrated solution after the crystallizing
out of salt from the sea water, are very reach in bromine
and offers a good raw material for the manufacture of bromine.
Sea bittern having at least 2.2 gm/lit bromine , is most suitable
for the manufacture of bromine. The technology for manufacture
of bromine has been developed at Central Salt and Marine Chemical
Research Institute, Bhavnagar, India and the technology has
been licensed to 9 salt manufacturers and five of them are
in production. The capacity utilization of these plants during
the last ten years was noticed to be varying between 30 %
to 70 % and their total production always remained far below
the demand of bromine in the country. The total demand of
bromine for the year 2000 AD has been projected to be 700-
800 tonnes and to meet the requirement of bromine in the country
,the production capacity of the country has to be increased
by at least 60 %. Therefore the production of bromine offers
a good prospects to those entrepreneurs who has access to
sea bittern.
Process
The 30o Be' bittern from the reservoirs
is taken in sump tank and then fed to the chlorinating tower.
After perchlorination, the cold bitterns is preheated by hot
recycle brine and the fed at the top of a stripping tower
wherein steam is introduced at the bottom to further heat
the bittern to boiling point and strip the bromine liberated
by chlorine. Sulfuric acid is also added to the tower to facilitate
stripping of bromine. The liberated bromine with excess steam
is passed through the two stage condenser to separate steam
and uncondensed bromine and chlorine gas mixture is scrubbed
in the chlorinating tower. The crude bromine is separated
from water in gravity separator and further purified by fractional
distillation and passing through sulfuric acid column. The
water condensed overhead of stripping tower and the impure
gas emerging from the distillation column are recycled. The
debrominated effluent brine is treated with caustic soda and
is used for pre-heating chlorinated bittern.
Plant Parameters
| Capacity, TPA |
150 |
| No.of Shifts / day |
3 |
| Working days / Yr. |
300 |
| Land Area, m2 |
4000 |
| Covered Area, m2 |
600 |
Manpower
| Managerial |
9 |
| Skilled |
15 |
| Unskilled |
26 |
Raw Material
| (Tonne per Tonne |
of Product) |
| Sea bitterns |
4.33 |
| Sulphuric acid |
0.002 |
| Chlorine |
0.004 |
| Caustic soda |
0.002 |
Utilities (Per Tonne of Product)
| Power, KwH |
10 |
| Water, KL |
1 |
| Steam, Tonnes |
0.27 |
| Coal , Tonnes |
0.05 |
Plant & Machinery
| Bittern preheater |
Separator |
| Stripping tower |
Level gauges |
| Steam condenser |
Boiler |
| Bromine condenser |
Flow meters |
| Distillation column |
Br. cooler |
For further information please
contact :
National Research Development Corporation
( A Government of India Enterprise )
20-22, Zamroodhpur Community Center
Kailash Colony Extension
New Delhi 110 048. India
Tel: 91-11-26419904, 26417821, 26480767, 26432627
Fax: 011-26231877, 26460506, 26478010
Website: www.nrdcindia.com
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