CAPD a succour to fabric drying energy costs

17 Apr '08

2 min read

In textile wet-processing, drying requirements are frequent and form a major constituent of thermal energy cost.

Conventional drying of textiles are carried out either by contact drying method (e.g.cylinder drying) or by hot air drying (e.g. stenter/float dryer) heated by steam or thermic fluid after moisture removal by either squeeze rollers or vacuum extractor.

A new development in drying is the energy effficient “Convective Air Pre-Drying System"(CAPD), which uses the atmospheric air stream of high velocity to dry out the wet fabric partially before it enters into main dryer and results in less requirement of thermal energy for drying.

CAPD system has an efficient forward curved fan of, 600M3/min. capacity (1.5 HP motor) supplying air through a duct system having slit with air velocity of 15 m/sec to impinge on the fabric.

This high velocity air helps in removing a part of the surface moisture in fabrics by the principle of pressure differential between atmospheric air & vapor pressure. Field trials were conducted in an 18 cylinder dryer in bleaching section with CAPD pre-drying system installed before drying cylinder.

The result shows that there was a reduction in % MR (Moisture Retention) by 7 to 12.5% due to which the steam saved was around 10%. The total fuel saving is equivalent to 100 tones per annum whilst the payback period is around 6 months.

Northern India Textile Research Association

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