Page 173 - CW E-Magazine (23-4-2024)

Special Report

using fl uorocarbon polymer fi bres, Ongoing development efforts for in transforming them into solar panel
have been introduced. Membrane Cell processes are focused chips.
on reducing energy consumption even
Membrane Cells further, with innovations in electrode The present world capacity of
Membrane Cells are the most envi- coatings, optimized ‘zero-gap’ elec- caustic soda is 62-mtpa and that of
ronmentally benign of all the cell tech- trode design, and improved membrane chlorine is 58-mtpa, distributed amongst
nologies as they use a non-permeable materials. approximately 580 plants distributed
ion exchange membrane and have elec- over 650 sites. China is the largest
tricity requirements like Diaphragm Uses producer as well as largest consumer
Cells. The caustic solution produced Caustic soda is a versatile industrial of caustic soda.
are essentially salt-free and more con- chemical. Its largest uses are in pulp &
centrated than that obtained from paper, detergent and chemical indus- Indian scenario
Diaphragm Cells. Actually, the Membrane tries. Caustic soda is also used in In India the fi rst caustic soda plant
Cell is a modifi cation of Diaphragm alumina, oil & gas and textile industries, was put up by The Travancore Cochin
Cell wherein the diaphragm is replaced mostly for its alkalinity value. Chemicals Ltd. (TCC) at Udyogmandal,
with a permselective ion exchange Kerala. It started operations in January,
membrane, which inhibits the passage The consumption of caustic 1954 with a capacity of 20-tpd (tonnes
of chloride ions, but allows positively soda in different end-use sectors are per day). TCC was established by She-
charged sodium ions to move through approximately as follows: Textiles 21%, shasayee Brothers (Managing Agent of
freely. Membrane Cell technologies alumina 12%, preparation of inorganic Fertilisers and Chemicals Travancore,
were developed individually for licensing chemicals 13%, pulp & paper 8% and FACT). The venture started as partner-
since 1950 by Asahi Chemical Indus- soaps & detergents 7%. ship concern in the name of Travancore
tries, Asahi Glass, Chlorine Engineers, Mettur Chemicals with FACT and Mettur
ICI, Lurgi, De Nora, Uhde, etc. Chlorine is used in the manufac- Chemical & Industrial Corporation (MICC).
ture of vinyl chloride monomer, ethy- The company changed to TCC in
Oxygen Depleted Cathode Membrane lene dichloride, chlorinated solvents, course of time with the Kerala Govern-
Cells bleaching powder (CaOCl ), among ment taking a major share. The pre-
2
In the Oxygen Depleted Cathode other uses. About 20% of chlorine pro- sent capacity of the plant is 175-tpd of
(ODC) version of Membrane Cells, duced is consumed for polyvinyl chlo- caustic soda.
the cathode reaction is different from ride (PVC) manufacture. Chlorine has a
the usual membrane electrolysis. In the major use as industrial bleach in paper & In 1972, Grasim’s Chemical Busi-
ODC version, pure oxygen is added to pulp and textile industries. Having ness was set up to manufacture caustic
the cathode. This reacts with hydrogen oxidising property, chlorine has many soda for meeting the needs of the
to form water and requires less electri- other industrial uses. The vast majo- company’s viscose staple fi bre (VSF)
city than normal membrane electrolysis. rity of water supply systems across unit. After the merger with Aditya Birla
the world use chlorine to provide safe Chemicals in 2016, Grasim is India’s
Regardless of the technology, cells drinking water. The treatment of water largest caustic soda producer, and mar-
are arranged in series electrically, with with chlorine began in London after ket leader. Their manufacturing capa-
each circuit consisting of several rows cholera broke out in 1850. Chlorine city is spread over multiple locations.
of cells. Two adjacent rows may share has been used to purify drinking water Chemfab Alkalies Ltd. was the fi rst unit
a brine distribution line and collec- in USA since 1908. As per LIFE maga- in India to set up a unit with Membrane
tion systems of chlorine and hydrogen. zine “The fi ltration of drinking water Cell technology in 1985 at Kalapet,
Each row is equipped with a pipeline plus the use of chlorine is the most Puducherry. Chemplast Sanmar started
for collecting caustic. Electrolysis signifi cant public health advance of as a single operation unit in 1967 at
occurs when direct current fl ows be- the millennium.” Mettur and became a multinational
tween electrodes through brine. Chlorine company over the years.
then collects at anode plates, bubbling A few hundred pharmaceuticals are
through the brine and is carried away dispensed as chloride salts. Chlorine The total installed capacity of caustic
by the chlorine collecting system. also plays an important role in harness- soda in India is about 4.55-mtpa, which
Hydrogen generated at cathode is similarly ing solar energy, purifying the silicon is about 4% of world capacity. The total
collected. found in grains of sand and helping production is about 4.38-mt.

Chemical Weekly April 23, 2024 173

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