Download Report

T
ECHNICAL ARTICLE
How to Save the Ozone Layer? Role of Textile Industry
Prof. T. Saravanak Kumar
On behalf of GTZ
Ms. Meghna Udgire
On behalf of GTZ
Dr. G. S. Nadiger
Textile Consultant.
The depletion of ozone layer is the major concern of the day and steps need to
be initiated to address this issue. The article reviews the causes of depletion of
ozone layers with respect to the textile processing industry and offers the solutions
to be implemented for phasing out of a key factor causing this problem, viz.,
Carbon Tetra Chloride (CTC).
INTRODUCTION
Ozone is naturally present in our atmosphere. Each molecule
contains three atoms of Oxygen. Ozone is found primarily in
two regions of the atmosphere. About 10% of atmospheric
ozone is in the troposphere, the region closest to Earth (from
the surface to about 10-16 kilometers). The remaining 90%
Ozone resides in the Stratosphere, primarily between the top
of the Troposphere and about 50 kilometers altitude. The
large amount of Ozone in the stratosphere is often referred
to as the “Ozone layer”. Ozone in the Stratosphere absorbs
the Sun’s biologically harmful ultraviolet-B (280-315 nm) radiation. The depletion of stratospheric Ozone by human activities is due to the emission of Ozone depleting gases
containing Chlorine and Bromine at Earth’s surface. Most of
these gases accumulate in the lower atmosphere because
they do not react and do not dissolve readily in rain or snow.
Free Chlorine radical break the ozone molecule into chlorine
monoxide and oxygen molecule on a cyclic reaction.
Research studies conducted in 1980s, have revealed that
CFCs and CTC and many other man-made chemicals were
destroying the delicate Ozone layer. The ozone layer, a layer
of gas in the lower stratosphere protects the flora and fauna
on earth from harmful ultraviolet-B rays from the sun. Due to
the depletion of ozone layer, UV radiation on the earth increases which can damage the ecosystems and have an adverse impact on human health leading to skin cancer and
cataract problems.
December 2009 O Man-made Textiles in India
417
GLOBAL INITIATIVES
Decisive and swift global actions followed the discoveries,
first with the 1985 Vienna Convention and then with the
Montreal Protocol in 1987.
years. Hence, every drop of CTC reduction contributes to the
protection of the ozone layer. Also important is the fact that
a few litres used by “many” constitute a substantial volume
of CTC on the aggregate.
GTZ INITIATIVES TOWARDS CTC ALTERNATIVES
As per the Montreal Protocol production and consumption of
CTC for emissive uses has been phased out gradually every
year and will have to stop by 31st December 2009 worldwide. Hence CTC availability is becoming difficult every
passing day. Therefore it is necessary to find “safe alternatives”. CTC Alternatives however are not easy to “search” or
“assess”. No single substitute exists to replace CTC in all its
applications. Danger also lies in the fact that industry may
unknowingly substitute CTC with a substance that is also
harmful to environment and health.
The Montreal Protocol provided the first global controls on
ozone depleting substances (ODS) including CFCs and CTC.
In the decade that followed the Montreal Protocol was made
more stringent as mounting evidence proved stratospheric
ozone depletion and the ozone hole in particular, were
caused by emissions of manufactured chemicals. All countries have signed the treaty and have taken control measures
to phase out these harmful chemicals.
RELEVANCE TO TEXTILE INDUSTRY
Carbon Tetrachloride (CTC) is a solvent which is mainly
used in the metal cleaning and textile industries. It is also
used as feedstock in the manufacture of CFCs and DV Acid
Chloride. Carbon Tetra Chloride – commonly known as CTC
amongst many industries is a very popular solvent. It removes all contaminants (like oil and grease) and gives a
very clean product. Till a few years ago, CTC was used
vastly as it was cheap, non-flammable and very effective.
CTC has been used in the Textile industry for the following
applications.
1) Stain removal in fabrics/ garments: To remove oily and
greasy stains in fabrics and garments.
2) Cot and roller cleaning: To prevent lapping, CTC is
applied on the surface of cots and rollers and wiped with
cloth to remove the contaminants.
3) Electrical contact cleaning: Large switchgears develop
carbon deposits over a period causing power losses.
CTC is used to clean them.
CTC users often feel that using a few litres of CTC per year
should not cause much harm. However, the proven fact is
that a single chlorine atom liberated from CTC, can destroy
up to one lakh ozone molecules in its life span of 30-40
418
Man-made Textiles in India
O
December 2009
German Technical Co-operation (GTZ) is an international
cooperation enterprise for sustainable development with
worldwide operations. GTZ Proklima is a sectoral programme
which implements bilateral and multilateral projects in order
to assist partner countries in fulfilling their obligations under
the Montreal Protocol. GTZ Proklima is the largest partner of
the Multilateral Fund of the Montreal Protocol. GTZ Proklima,
on behalf of the governments of Germany and France and
under the overall coordination of the Ozone Cell, Ministry of
Environment and Forests, GOI, is implementing the CTC
phase out project in India.
To assist the industry in making the inevitable transition, GTZ
Proklima has been mandated, to provide industry with technical assistance (free of cost), to help and ensure a “safe
and informed transition” from CTC to alternatives.
a) CTC alternatives in stain removal
CTC has been popular in stain removal due to its high
cleaning efficiency and quick drying. GTZ Proklima has put
efforts on analysing the viable alternatives systematically. The
ideal stain remover should be free from ODS, colourless,
efficient, cost effective, preferably odourless, non carcinogenic, non toxic and if possible non flammable as well.
However, there is no solvent in which we find all these qualities to a satisfactory level.
The evaluation of alternative stain removers has been carried
out in three phases:
Phase 1: Screening for the possible presence of ODS
The stain remover is first tested for the presence of ozone
depleting substances (ODS). Priority is given to non-proprietary solvents.
Phase 2: Performance evaluation of stain removers
Only those stain removers which qualify in phase 1 are
selected for this phase. An evaluation of actual stain removal
is carried out with part-simulated oil stains and industry
tures. These concerns lie specifically in the flammability of ordinary hydrocarbon solvents such
as Acetone, Mineral Turpentine
and White Petrol. A potential
cancer risk is associated with
chlorinated solvents such as
Trichloroethylene (TCE) and Benzene, which till date are widely
used in India; Constituents of
most proprietary solvent mixtures
are not known and thus it is also
unknown whether they contain
flammable and/or cancer-causing constituents.
Table 1. Evaluation of different stain removers
Cotton
fabric
Silk
fabric
Wool
fabric
Viscose
fabric
Polyester/
Cotton
blend
fabric
Polyester
fabric
Per Chloro Ethylene
3
3
3
3
3
3
White petrol
3
3
3
3
3
3
Mineral Turpentine Oil
3
2
3
3
3
3
Hexane
3
3
3
3
3
2
Xylene
0
3
3
3
0
2
Methyl Ethyl Ketone
0
0
2
1
2
3
Ethyl acetate
0
1
1
3
0
1
Iso Propyl Alcohol
1
1
0
0
1
1
Acetone
1
2
0
0
1
0
CTC
3
3
2
3
3
3
Remarks
Efficacy
Stains fully removed
3
Mild traces seen after de-staining
2
Traces seen significantly after de-staining
1
Stains not removed
0
It is important to note from Fig.
1A and 1B that many of the alternatives to CTC are cost effective and also reduce the idle time of the draw frame and
comber. This indeed is a positive aspect of the CTC phase
out so that the processing of textiles can be done satisfactorily.
250.00
samples. The tests are conducted on white and dyed
samples with two time delay conditions (next day and 15
days later). During testing the important parameters like volume of stain remover, time taken, level of stain removal and
operator’s comfort are recorded and analysed.
cost of substance in INRfor one month
200.00
Draw frame stoppage in minutesfor one month
150.00
100.00
50.00
0.00
Tu
rp
en
tin
e
Oi
Pe
l
rC
Xy
hl
le
or
n
e
o
Et
hy
le
ne
Pe
Et
tro
h
l
Iso yl a
ce
Pr
ta
o
te
py
M
et
lA
hy
lco
lE
h
th
ol
yl
Ke
to
W
n
e
hi
te
pe
tr
ol
NC
th
in
ne
r
Ac
et
on
e
He
xa
ne
Phase 3: Additional assessment
M
in
er
al
Stain removers are further assessed for their impact on
discolouration, workers’ health and safety. The consolidated
results are given in Table 1.
CT
C
Name of the alternative
Fig. 1A. Comparative Cost analysis of the Alternatives for cots
cleaning
b) CTC alternatives in spinning
The following solvents are found to be effective alternatives
to CTC for cleaning of cots and rollers.
350.00
Cost of subst ance
300.00
Com ber st oppage t im e in m inut es
250.00
1. Per Chloro Ethylene
200.00
150.00
100.00
2. Mineral Turpentine Oil
CTC ALTERNATIVES – BENEFIT & RISK ASSESSMENT
Based on extensive studies conducted by GTZ Proklima, a
number of “CTC alternatives” for a variety of applications
across industry sectors have been identified. Every CTC
alternative is thoroughly tested on parameters of “performance”, “occupational health”, “environmental impact” &
“industrial safety”.
The presentation of substances in categories draws attention
to the fact that concerns exist regarding certain properties of
some of the substances, particularly solvents and their mix-
e
an
ex
H
A
ce
t
on
ne
e
r
ol
tr
N
C
th
in
pe
W
hi
te
yl
CT
C
e
ol
on
K
et
at
lA
py
M
et
hy
lE
th
ol
ac
et
yl
Pr
o
Is
o
Et
h
lc
oh
e
e
tr
en
Et
h
o
Pe
ne
Pe
r
Ch
l
or
Xy
le
ti
en
rp
M
in
er
al
Tu
4. Xylene
yl
ne
O
0.00
il
50.00
3. Ethyl Acetate
Fig. 1B. Comparative Cost analysis of the Alternatives for cots
cleaning
Table 2 and 3 provide a systematic approach to identify the
associated Environment, Health & Safety issues such as:
·
Inhalation – common to all ordinary hydrocarbons and
thus a critical issue;
·
Skin – common to all ordinary hydrocarbons & some
aqueous substances and thus a critical issue;
·
Environment – typical for aqueous substances but a critical issue for solvents;
December 2009 O Man-made Textiles in India
419
Table 2. Data on the health and safety features of various category of substances used
in the Textile industry.
Group
Hazard
Inhalation
Skin
Environment
Flammability
Flashpoint
in 0C
High
Severely
Toxic
Severely
toxic
Very
hazardous
Extremely
flammable
<0
D
Very toxic
Very toxic
C
Toxic
Toxic
B
Harmful
A
Irritant
None
none
E
–
low
Based on:
Health &
Safety
Executive
(HSE),
United
Kingdom
Highly flammable
0 = 21
Flammable
21 = 55
Harmful
Combustible
55 = 93
Irritant
Possibly
combustible
93+
Non-flammable
None
Hazardous
not classified
Federal
Institute for
Occupational
Safety & Health
(BAuA),
Germany
European
Union
(adapted)
European
Union
(adapted)
Table 3. Data on the health and safety features of various category of
substances used in the Textile industry.
Substance
Inhalation
Skin
Environment
Flammability
PCE
Very toxic
Toxic
Very hazardous
Non-flammable
White Petrol
Very toxic
Toxic
Very hazardous
Highly flammable
Toxic
Very toxic
Very hazardous
Flammable
Highly flammable
MTO
Hexane
Very toxic
Toxic
Very hazardous
Xylene
Harmful
Harmful
Not classified
Flammable
Methyl ethyl
ketone
Irritant
Irritant
Not classified
Highly flammable
Ethyl acetate
Irritant
Irritant
Not classified
Highly flammable
IPA
Irritant
None
Not classified
Highly flammable
Irritant
Irritant
Not classified
Highly flammable
Very toxic
Toxic
Very hazardous
Non-flammable
Acetone
CTC
The selection of a solvent
should be made so as to
minimize the hazard. As is
apparent from the ratings
above, most of the substances are classified as
“Very toxic” for “Inhalation”
and “Toxic” under “Skin”.
Safe use can therefore not
be ensured by a prudent
selection alone. Table 3
shows the hazard ratings of
the alternatives discussed in
this article.
CONCLUDING REMARKS
While choosing a stain remover, it is important to assess its properties related to
health and safely. The safety features namely
Inhalation, Skin irritation, Environment and
Flammability need to be established. While
some properties such as flammability can be
easily assessed, others require extensive,
complex and time consuming processes. The
test results clearly indicate that there are viable alternative solvents already available in
the market. Though Per Chloro-ethylene,
White petrol, Mineral turpentine oil and hexane are effective on all fabrics, they are toxic
in case of skin contact and inhalation. The
user is advised to wear a mask and suitable
gloves to mitigate these health hazards.
Flammability – common to all ordinary hydrocarbons but
absent in aqueous substances. Hence it is a critical issue for solvents
These substances are also hazardous to
aquatic life and hence discharging the effluent to water body
(ground water, river etc) is to be discouraged. Care should
be taken in storage and packing based on the flammability.
Each hazard has been further classified into six grades and
each grade is characterized through a corresponding colour
shade. The least risk is marked in green, followed by shades
of yellow and orange. Red represents the most severe risk.
GTZ Proklima has also published technical booklets on CTC
alternatives for stain removal and spinning applications
which can be downloaded for free from the resourceful
website www.ctc-phaseout.org.
·
420
Man-made Textiles in India
O
December 2009
Copyright of Man-Made Textiles in India is the property of Synthetic & Art Silk Mill's Research Association
and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright
holder's express written permission. However, users may print, download, or email articles for individual use.