| Process Optimization in Textile Dyeing | India | - | Full scale |
MANUFACTURE OF TEXTILES # 24
Background:
This case study shows a successful example in India of how National Cleaner Production Centers have assisted companies to rationalize their production process and save money on raw materials, energy, water, and waste treatment costs.
Oriental Dyeing and Finishing, a textile hosiery processing industry located in Ludhiana, India, bleaches and dyes cotton hosiery fabric on a job-order basis. Major process steps are scouring, bleaching, dyeing and finishing. The entire process is carried out using winches. After the first three steps, fabric is rinsed to remove extracted impurities and residual chemicals. After wet processing, the fabric is dried in a tubular, steam, hot air dryer.
Oriental Dyeing and Finishing process about 4,000 kilos of fabric per day. The company has an annual turnover of about US$ 700,000 and employs 150 people.
Pressure from the Pollution Control Board to comply with environmental regulations was the catalyst for a Cleaner Production program. Other factors were a very high fuel consumption (compared to other industries) and a very high redyeing rate.
Cleaner Production Principle:
Process modification
Cleaner Production Application:
A CP assessment identified 34 options, of which 22 have been implemented, including:
| Reduction of liquor to material ratio in winches (from 10:1 to 8.5:1); |
| Reduction of specific alkali consumption in scouring by 15 percent; |
| Eliminating one washing step by providing five minutes drag out time after each discharge; |
| Replacing steam hot air dryer with direct fuel-fired hot air dryer. This means a reduction of drying cost from Rs. 1.20 per kilo fabric to Rs. 0.60 per kilo; and |
| Optimizing boiler efficiency by controlling draft (additionally installed damper) and fuel firing practices. |
Environmental and Economic Benefits:
Implementation of 22 CP solutions resulted in the following environmental benefits:
| Reduced water consumption by 20 percent; |
| Reduced COD by 20 percent; |
| Reduced particulate emission from 300mg/Nm to less than 50mg/Nm, therefore meeting air pollution norms (150mg/Nm) without any control equipment; |
| Reduced redyeing/reprocessing rate from 6 to 2 percent (67 percent reduction in redyeing/reprocessing). |
The company invested US$ 10,000 to implement 22 CP solutions, resulting in annual savings of US$ 35,000 with a pay-back period of less than four months. Estimated total investment and annual savings for all 34 solutions would be US$ 260,000 and US$ 100,000 respectively.
Constraints:
None mentioned.
Contacts::
Review Status:
This National Cleaner Production Center case study was presented in the document "NCPC Case Studies" available from UNEP IE or UNIDO (addresses above). It was formatted and edited for the ICPIC diskette in August 1997. It has subsequently undergone a formal technical review in September 1998 by Dr. Prasad Modak, Environmental Management Centre, Mumbai, India..