Orientation Programme for GPCB

on

“Environmental Issues & Solution for the

Textile Sector”

July 06, 2013

Presentation

on

“Overview of Opportunities for

Improvements in Textile Sector”

Nitesh Patel Junior Advisor

GIZ-IGEP, Gandhinagar

Transformation of raw textile product to final usable form involves four different stages.

1. Fibre production

2. Intermediate dry processes like spinning, weaving and knitting

3. Intermediate wet processing like slashing, desizing, kiering / scouring, bleaching, mercerising and dyeing and

4. Finishing like printing, cutting, stitching, packing etc.

Note: Source of major environmental issues - intermediate wet processing carried out on yarn or fabric

Sizing Polyvinyl alcohol, Carboxy methyl Cellulose, Oils, Waxes,

Adhesives, Urea, Diethylene glycol, etc.

Desizing Enzymes, Sulphuric acid, Detergents and Alkali

Scouring Sodium hydroxide, Sodium Carbonate, surfactants,

chlorinated solvents

Bleaching Hypochlorite, hydrogen peroxide, acetic acid.

Mercerization Sodium hydroxide, surfactants, acid, liquid ammonium

Dyeing Dyestuffs, auxiliaries, reductants, oxidants

Printing Dyes (acids or alkalis), pigments, kerosene, binders,

ammonia, xylenes.

Chemical

finishing

Formaldehyde, phosphorus, ammonia, silicone, fluorocarbon

resins, toluene,

zircon salts etc.

Inputs to wet processes

Unfixed Dyes for Various Processes

Fabric Dye type Unfixed dye (percentage)

Wool and

Nylon

Acid dyes/reactive dyes for

wool 7 – 20

Pre-metalized dyes 2 – 7

After chromes 1 – 2

Cotton and

viscose

Azoic dyes 5 – 10

Reactive dyes 20 – 50

Direct dyes 5 - 20

Pigment 1

Vat dyes 5 – 20

Sulphur dyes 30 – 40

Polyester Disperse 8 – 20

Acrylic Modified basic 2 – 3

Polypropylene Spun dyed N/A

Source: Water and Chemical use in the Textile Dyeing and Finishing

Industry (GG62 Guide) (http://www.envirowise.gov.uk/uk.html)

Finishing Industry (Textile wet processes) - Waste Water

& Solid Waste

Process Input material Function (purpose)

Product Effluent Solid wastes

Desizing

Singed fabric,

Enzymes,

Acids (Sulphuric)

To remove

size material

from woven fabric

Fabric

free from size

BOD from sizes,

lubricants, biocides, antistatic Compounds

Fibre

lint, yarn

waste,

cleaning materials

Scouring

Knitted or

desized woven

fabric, Alkaline

or solvent Solutions

Cleaning

fabric from impurities

Clean fabric

High BOD and

temperature very high

pH, fats, waxes,

detergents, size mix

residues, solvent residues

Little or

no

residual waste

Bleaching

(for

natural fibres)

Scoured fabric,

hydrogen

peroxide, Hypochlorite

Eliminating

unwanted

colour matter

decolorizing colour Impurities

White

bleached fabric

Low to moderate BOD,

high pH and

temperature, bleach and additives Residues

Little or more

Process Input material Function (purpose)

Product Effluent Solid wastes

Mercerizing

Woven or knitted

cotton fabric,

Caustic soda (15-

20%), Acid

To give lustre,

more strength,

and higher

affinity for Dyes

Mercerized

woven or

knitted

fabric

Very high pH,

dissolved

solids, some,

BOD, NaOH

Little or

none

Dyeing

Woven or knitted

fabric, dye stuffs,

auxiliaries,

reductants and

Oxidants

Add colour

and intricacy

to fabrics

Dyed fabric

Depending on

type of dye,

dissolved

solids, COD,

heavy metals

causing

toxicity, BOD

Chemical

residues,

fabric

scrap

Printing

Woven or knitted

fabric, pigments and

dyes, acids or alkalis,

softener, binder,

emulsifier Solvents

Printing colour

and

patterns on

Fabric

Printed

fabric

High COD

and salt

content

solvents toxic

metals BOD,

foam, heat

Chemical

residues

Source: Self-Monitoring Manual, Textile Industry, Egyptian Pollution Abatement Project,

Ministry of State of Environmental Affairs

Water Consumption & Effluent Discharge from Wet Processing

Activities Water consumption

(Litres/100 kg)

Effluent

Variation

(Litres/100 kg) Variation Average

Sizing / Slashing 50-820 435 50-820

Desizing 250-2100 1175 250-2100

Kiering / Scouring 2000-4500 3250 2000-4500

Bleaching Yarn (Hypochlorite) 2400-4800 3600 2250-4600

Yarn (Hydrogen Peroxide) 2400-3200 2800 2250-3050

Cloth (Hypochlorite) 2400-3200 2800 2250-3050

Cloth (Hydrogen Peroxide) 4000-4800 4400 3800-4600

Mercerising 1700-3200 2450 1700-3200

Dyeing Yarn (Light and Medium

Shades)

3600-17600 10600 3500-17500

Yarn (Dark Shades) 3600-4800 4200 3500-4700

Yarn (Vary Dark Shade) 4800-6400 5600 4700-6300

Cloth (Light and Medium

Shades)

6600-8800 7700 6500-8700

Cloth (Dark Shades) 7800-9600 8700 7700-9500

Cloth (Very Dark Shade) 10400-12800 11600 10300-12700

14300-17600 15950 14200-17500

Source: Data computed from Manivasakam (1995) and MSE Study (1998)

The drying process

Challenges and solutions in the drying process

Challenges:

Rotating at 50-60 rpm

Normally industries

insulate with

glass/mineral wool

Water resistance very

low

Insulation peel off

within 2-3 month

Promote corrosion

Solution:

Resin bounded

mineral wool slabs

Water vapor

resistance factor: 1

Chemically neutral,

neither cause nor

promote corrosion

Economic savings and payback time

Drying Drums, Nos 38, Ø1.5m, No 1, Ø

4.5m

Total not insulated area: 128 m2

Temperature: 120°C

What is the impact if this drums were

insulated up to the latest standards:

Investment: Rs. 500,000

Cost Savings: Rs. 1,200,000/ Year

Payback time: 5 Month

Waste Heat Recovery from Jet Dyeing Machines

The drained water from jet machines is passed through one

side of the shell and tube heat exchanger and cold water to

be heated on other side

S. No. Parameter Units Details

1. Quantity of hot water drained available liters/day 31000

2. Average quantity per day (80%) liters/day 24800

3. Temperature of hot drain water 0C 90

4. Quantity of heat can be recovered kCal/day 992000

5. Present Boiler efficiency %age 65

6. Calorific value of fuel kCal/kg 6000

7. Fuel savings per day kg/day 254

8. Operating days per annum days 350

9. Fuel saving per annum Tonne/annum 89

10. Fuel cost Rs./tonne 3800

11. Monetary savings per annum Rs. In lakh 3.38

12. Investment for tank, heat exchanger

and

pumping system

Rs. In lakh 3.11

13. Payback period Year 1.08

Case Study of Surat Cluster

Exhaust Control from Stenter Machines

Stenters are mainly used in textile finishing for heat-setting, drying,

thermosol processes and finishing.

In fabric finishing, each textile substrate is treated on average 2.5

times in a stenter.

Stenter happens to be the largest Energy Consuming Machinery

available in a textile Dyeing and Finishing Industry.

Thermal Energy required for stenters is supplied by Thermopac. The

hot thermal fluid at a temperature of 235°C to 300°C

Energy consumption of energetic optimized stenters is in the range of

3500-4500 kJ per kg of textile (1-1.5 kg of coal).

Manual control of exhausts is generally very difficult since the

expected airflow patterns and the ones found in practice vary

considerably

Hence the tendency to leave them fully open

Optimisation of exhausts can be achieved by controlling the exhaust

humidity to between 0.1 and 0.15 kg water/ kg dry air

Typical Sankey diagram for a

stenter having no Energy

Conservation Measures

Typical Sankey diagram for a

stenter having Energy

Conservation Measures

Investment: Rs. 3,50,000

Cost Savings: Rs. 2,00,000/ Year

Payback time: 21 Month

Thermal Energy Recommendations Implemented by the

process house unit situated in Mumbai

Installation of automatic blowdown control system at

boilers; about 50% blowdown quantum reduced.

Repair of pressure reducing valves in 14 steam supply

lines.

Attending malfunctioning steam traps (32 Nos.)

Closing trap by-pass line valves (13 Nos.)

Providing individual trapping system instead of group

trapping system at 3 drying range machines.

Replacing/repairing punctured/leaking condensate

lines in Finishing section.

Installation of heat recovery system from hot effluents

available from initial washes in Open Width Bleaching

Range.

Installation of automatic control valves in the drying

range machines

Plugging steam leakages (75 Nos.).

Thorough cleaning and tuning of Thermopac No.1, its

thermal efficiency improved from 75 to 79%.

Thermal Energy Recommendations Implemented by the

Unit

Fuel Saving (FO) : 380 KL (Rs.40 lakhs)/Annum.

Fuel saving as % of consumption : 3%

CONSERVATION OF WATER IN TEXTILE

Sources for Waste Water Generation in Textile Industries

BLEACHING in Preparatory Section Of Processing.

COOLING WATER for the Jet Dyeing Machine / Rubber Belt

AFTER WASH is one of the MAJOR waste water generating Source In Dyeing

MORE THAN 7 TIMES WATER is used in After Wash than in Dyeing Process

WASHING UNIT WATER of Printing M/C Blanket & Washing Of Screen

Most of the Waste Water is COLOURED

HOW TO REDUCE THIS ?

WATER CONSERVATION OPPORTUNITIES IN

BLEACHING

1. Re-use of Collected Water from Various Bleaching Processes

Waste Water Source Re-use Destination

Waste water from acid wash Raw water for chemick wash

Waste water from chemick wash Raw water for kier wash & de-size wash

2. A- counter current system in washing m/c.

3. Water Saving in Bleaching by Continuous Bleaching Range

(C.B.R.)

Conventional Bleaching Continuous Bleach Range

Water requirement 20 To 25 liters per

Kg. of fabrics

Water requirement 10 To 12 liters per

Kg. of fabrics

Economical if per day production is

lesser than 5,000 Kg Or 50,000 meters

Economical if per day production is more

than 10,000 Kg Or 1,00,000 meters

4. Resource Saving by Bio Scouring Process (Newly Developed

Process)

Parameters Conventional Process Bio-Scouring Process Difference

Total turns 33 20 - 13 turn

Batch time 18 Hrs 10 Hrs - 8 Hrs

No. of drains 13 8 - 5 Drains

Water

consumption

3900 lit / batch 2400 lit/ batch - 1500 lit/

batch

Chemical cost 5.88 4.98 - 0.9 Rs./kg

Labor cost 1.05 0.58 - 0.47 Rs./kg

Electricity 0.72 0.36 - 0.36 kW/kg

Steam 1000 500 - 500 kg/batch

No Caustic Boil as well as No Chlorine used

WATER CONSERVATION OPPORTUNITIES IN

DYEING

1. After wash is required to remove the un-fixed dyes from the

fabrics this generates colored effluent

2. If the dye is more fixed on the fabrics the requirement of after

wash can be reduced

3. Use of bi / poly functional dyes can reduce the water

consumption and waste load in effluent

4. Change of the process of dyeing can help in water conservation

Minimum two after washes saved

800 liters per batch per jigger of 1000 meters

800 liters x 2 washes = 1600 liters water per batch of

1000 meters

if we have dyed / printed 10,000 meters of the fabrics

with bi-poly functional dye

1600 x 10,000 ÷ 1000 = 16000 liters of water can

be saved

COLD PAD BATCH DYEING

1. Significant cost and waste reduction as compared to

conventional method

2. Total elimination of the need for SALT and other specialty

chemicals like anti migrants, leveling agents [Reduces

chemical cost, waste load in effluents

3. Optimum utilization of dyes.

4. Excellent wet fastness properties.

5. Cuts energy cost (no steam required), Temperature is not

required for fixation

6. Cuts water consumption due to low bath ratio

7. Uniform dye quality achieved with even colour absorbency

and fastness

8. No batch to batch variation of shade (like exhaust dyeing)

SELECTION OF JET DYEING MACHINE

NEW L-SHAPE AIR FLOW M/C

LONG TUBE DESIGN AIR FLOW

RECENT DEVELOPEMENTS

ELECTROCHEMICAL DYEING TECHNOLOGY

PLASMA TECHNOLOGY FOR DYEING

SUPER CRITICAL CARBON DIOXIDE FULID

TECNOLOGY

COMBUSTION & AIR POLLUTION

Particulate Control

Pulse Jet Fabric Filter (PJFF)

Electrostatic Precipitators (ESPs)

Upgrade/Enlarge ESP

Add flue gas conditioning

Wet ESP

Wet Venturi Scrubber

Electrified Filter Bed (EFB)

Recyclone

Acid Gas Controls

Dry Scrubber

Spray Dry Absorber (SDA)

Circulating Dry Scrubber (CDS)

Wet Scrubber

Direct Sorbent Injection (DSI)

Wet ESP

Wet Venturi Scrubber

CO/VOC Controls

Oxidation Catalyst

Regenerative oxidation catalyst

SCR- to maintain NOx compliance

Thermal Oxidizer

Upgrade air system

Install high energy burners

Resource Efficiency is not a question

of latest technology but of Best

Technique!