Reuse of cooling water from singeing machines

 

Technical description

 

In the woven fabric textile finishing industries, singeing is the first process step where greige fabric is passed through the singeing machine prior to wet pretreatment. Singeing operation is employed to destroy singes and tufts on the surface of the fabric, by its direct exposure to the flame, for a very short time. This process is required to improve the chemical uptake of the fabric, by preventing uneven impregnation.

Greige fabric is allowed to pass over the open flame of the burners through rollers where loose hairy fibers protruding from the surface of the fabric are burnt. Cooling water is continuously supplied at the inside of the rollers of the singeing machine to keep them cool which become hot by the direct exposure of the flame. This cooling water absorbs heat of the rollers and becomes warm at about 40-45oC temperature. This is a warm and clean water stream which is generally wasted from the singeing machines (see Figure 1).

Figure 1: Cooling water wastage from singeing machine

This warm water stream can be collected and reused in any of the wet process machines (see Figure 2). Generally it is raw water. This water can be used at followings:

  • Washing water in the process
  • Showering water at wet scrubbers installed with steam boiler
  • Showering water at wet scrubber installed with singeing machines

Figure 2: Singeing machine in operation with cooling water being collected in blue container and reused as showering water at singeing wet scrubber

Achieved environmental benefits:

  • Water conservation
  • Reduction in thermal energy (warm water will require less steam for heating, in case if this water is used in the hot washes)
  • Reduction in greenhouse gases 
  • Reduction in hydraulic load of wastewater treatment plant 

Operational data:

Mostly raw water is used as cooling water in the singeing machines. Cooling water quantity varies from industry to industry. Generally its quantity is about 24 to 48 m3/day (8,400 – 16,800 m3/yr). Its value is USD 4,200 to USD 8400/yr (Rs. 0.63 to 1.26 million/yr).

Cross media effects:

No relevant cross media effect is known.

Technical considerations relevant to applicability:

This measure is applicable to all the woven fabric textile finishing industries where greige fabric is singed before wet processing. This measure does not require any major intervention in the process, no major infrastructure development and no technical human resource requirement. The cooling water from the singeing machine will be collected in a small underground pit. This pit will be attached with small pump and discharge pipeline. The discharge pipeline will be connected to multiple machines/sources with valves where this water is intended to be reused. In case of water requirement to specific machine, the valve for that machine or source will be opened for the water supply.

Economics:

Capital cost for the underground pit, small pump, pipeline and valves = USD 1000 –
USD 2000 (Rs. 150,000 – 300,000)

Annual saving = USD 4,200 - 8400 (Rs. 0.63 - 1.26 million)

Annual O&M cost = USD 1,630 – 3,360 (Rs. 250,000 - 500,000)

Simple payback period = 5.0 months

Additional benefit will be the reduction in hydraulic load and treatment cost of wastewater treatment plant.

Driving force for implementation:

  • Financial benefits
  • Resource conservation
  • Sustainability of textile business

 Reference industry:

  • The Crescent Textile Mills Limited, Sargodha Road, Faisalabad
  • Sarena Textile Industry Pvt. Ltd, Sheikhupura Road, Lahore


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