industry and environment - DTIE

Chemicals management
gases such as chlorine, sulphur dioxide and trioxide,
nitrogen oxides, and fumes of acid and organic
solvents. Much of the time, these by-products of
unit processes are recovered subject to the cost of
recovery and their market potential. They are normally
gases like SO 2 , HCl (hydrochloric acid, or
hydrogen chloride) and organic products. If they
are not recovered, they cause air pollution. A 100%
recovery rate is not possible; the unrecovered product
is vented from the stack.
Particulate matter emissions from the drying
and grinding operation are another source of pollution.
Concentrations can be as high as 500-600
mg/litre. Flue gas from the boiler is also a source of
air pollution in this sector. Very high particulate
matter emissions of the dyestuff in powder form
are a major source of air pollution from the
dyestuff production plant.
An emission standard exists for most types of
gases and particulate matter (e.g. 50 mg/litre in
the case of particulate matter).
Management of gaseous emissions
To meet emission limits, gases and fumes emitted
from the stack are generally scrubbed using
packed bed type scrubbers. Most SMEs in this
sector are unable to comply with the standards for
source or fugitive emissions.
Cleaner production in the chemical
industry (dye, dye intermediates
and pharmaceuticals)
Significant environmental degradation has
occurred in various parts of India due to rapid
development/industrialization. Greater environmental
awareness and activism in all quarters,
accompanied by the economic liberalization promoted
by the Indian government, have left Indian
SMEs struggling for survival. In the past decade
they have experienced a financial crunch at the
same time as growing pressure to improve their
environmental performance. End-of-pipe treatment
of waste and emissions is being promoted,
but with only limited success since it is cost-intensive.
And changing the form of the waste is not the
same thing as eliminating it. Over the decade only
a few cleaner production initiatives have been
undertaken, mostly as demonstration projects. A
few of these are briefly described below.
A cleaner production demonstration project
was carried out in 12 chemical plants in 2001-02
by the National Productivity Council, located at
Vapi, Gujarat. Participants were from the dye, dye
intermediates and pharmaceutical sectors. During
the project 788 cleaner production measures were
identified. By the end of 2002, 380 had been
implemented.
Implementing these measures required an
investment of Rs. 8.5 million. This investment is
expected to yield Rs. 40 million per year through
improved productivity and reduced environmental
load. The measures implemented include:
◆ use of purer grade naphthalene and of iron powder
having higher activity, leading to an annual net
saving of Rs. 0.18 million in addition to a 50%
reduction of organics in sludge;
◆ substitution of inorganic for organic acid in
UNEP’s definition of cleaner production
the final isolation of NMJ (a dye intermediate)
following purification, leading to an annual
net saving of Rs. 4.3 million and a 50% reduction
of effluent organic load;
◆ modification of acetonyl sulphonyl chloride
(ASC) cake washing (static material water
seeping through, changed to continuous stirring
of material while washing), leading to a
reduction of water and caustic consumption
and improved quality of ASC. This measure
produced economic savings of Rs. 6.6 million
per year for an investment of Rs. 10,000;
◆ increasing the height of the distillation column,
leading to improved recovery of isopropyl
alcohol at a bulk drug manufacturing
unit. This measure produced an annual net
saving of Rs. 0.8 million for an investment of
Rs. 0.38 million.
Ishan Dye Chem Ltd. (copper phthalo
cyanine dye intermediate manufacturer)
M/s Ishan Dye Chem Ltd. is a small-scale dye
intermediate unit that manufactures copper
phthalo cyanine (CPC), which is further
processed to produce alpha and beta blue dyes.
The unit produces 100 tonnes of CPC per
month. A cleaner production process was introduced
in order to reduce water consumption,
recover solvent effectively and conserve energy.
Major CP measures implemented are:
◆ installation of a rotary air lock in a raw material
feeding hopper to reduce solvent losses in
the work atmosphere. This measure resulted in
annual net savings of Rs. 1.8 million for an
investment of Rs. 0.1 million;
◆ increasing vacuum pressure from 400 to 700
mm Hg for improved recovery of trichlorobenzene
(TCB) from the heated mass in the vannulator.
This measure, which required an
investment of Rs. 0.5 million, led to annual net
savings of Rs. 1.3 million.
Metrochem Industries Ltd., Ahmedabad
(H-acid dye intermediate manufacturer)
M/s. Metrochem Industries Ltd. is a dye intermediate
manufacturing industry with a production
capacity of about 60 tonnes of H-acid (an important
dye intermediate produced from naphthalene)
per month. During the CP project 27 cleaner
production measures were identified, of which 12
were implemented. The unit invested Rs. 2.8 million
in implementing the CP measures. Annual
Cleaner production is the continuous application
of an integrated preventive environmental
strategy to processes, products and services to
increase overall efficiency, and to reduce risks to
humans and the environment. Cleaner production
can be applied to the processes used in any
industry, to products themselves, and to various
services provided to society.
For the production process, CP results from
one or a combination of conserving raw materials,
water and energy; eliminating toxic and dangerous
raw materials; and reducing the quantity
and toxicity of all emissions and wastes at source
during the production process.
For products, CP aims to reduce the environmental,
health and safety impacts of products
over their entire life cycles, from raw materials
extraction, through manufacturing and use, to
the “ultimate” disposal of the product.
For services, CP implies incorporating environmental
concerns into designing and delivering
services.
savings of Rs. 51.0 million were achieved, in addition
to a 34% reduction in pollution load, 20%
reduction in fuel consumption and 12% reduction
in electricity consumption. The most significant
CP measures implemented are:
◆ increasing batch size by 10% to 1100 kg of
naphthalene, producing immediate savings of
about Rs. 11.3 million per year;
◆ installing a pressure-reducing valve to lower
steam pressure from 12 to 5 kg/cm 2 in the reduction
vessel, resulting in savings of about Rs.0.8
million per year;
◆ stopping the mother liquor blower in order to
control the flow of the liquor to the incinerator in
the zero discharge, resulting in savings of about
Rs. 30,600 per year;
◆ increasing the amino concentration to 45°Be by
five-effect steam evaporator, resulting in the
reduction of caustic consumption, of mother
liquor generation, of the sulphuric acid requirement
in isolation and of the cost of incineration,
as well as better recovery of Glauber’s salt. This
option has led to savings of about Rs. 3.7 million
per year. Reduction of steam consumption alone
has produced savings of Rs. 1.9 million per year.
ADCI Dyechem Pvt. Ltd., Ahmedabad
(reactive dyes manufacturer)
M/s. ADCI Dyechem Pvt. Ltd. is a dye manufacturer
with a production capacity of about 2400
million MT/year of reactive dyes (40 different
dyes). During the CP project 32 cleaner production
measures were identified, of which 17 were
implemented. The unit invested Rs. 1.0 million
in implementing CP measures and achieved
annual net savings of Rs. 2.25 million, in addition
to a 56% reduction in pollution load and 65%
reduction in water consumption. The most significant
CP measures implemented are:
◆ using the first wash water from filter press cake
washing for wet cake dissolution;
◆ modifying product cake washing from three
times (1000 litres of water per batch) to a single
1500-litre wash;
◆ using the first wash water from spray dryer
washing for wet scrubbing of the spray drier. After
concentration, the scrubbing liquor is spray dried
to recover the product.
Alps Chemicals Pvt. Ltd., Ahmedabad (acid
dye manufacturer)
M/s. Alps Chemicals Pvt. Ltd. is a small-scale
UNEP Industry and Environment April – September 2004 ◆ 45