How much CO2 does residual moisture control on a stenter cut?

Between about 36 and 89 t a year on one pet coke stenter. BEE's Pali report claims 28.08 t of residual pet coke and 76 t CO2 saved by drying fabric to 7% moisture instead of 5%. Its own text counts only a 3% speed gain, which is 11.3 t of coke. Cost Rs 1 lakh.

Over drying, in numbers

• The audited stenter runs 0.07 kg a square metre polyester fabric, 1.2 m wide, at 60 m a minute.
• Fabric enters at 70% moisture and leaves at 5%, though its natural regain is 7%. Operators dry past the target because nothing measures it.
• Drying to 5% removes 196.56 kg of water an hour; drying to 7% removes 190.51 kg. That is 3% less water to evaporate.
• The fix: roller sensors at the stenter exit read moisture from the fabric's electrical resistance, and a controller speeds the fabric up until the set moisture is reached. Fitting takes about a day.

Where 28 t comes from, and why it is the top end

The report divides that 3% by the stenter's 39.7% evaporation share to get 7.5% of its 3 lakh kcal an hour: 22,500 kcal an hour, or 3.9 kg of coke at 8,200 kcal a kg and a 70% thermopac, over 7,200 hours. Dividing magnifies the 3%. The report's own description says it counts a 3% rise in fabric speed for the same heat. That is 9,000 kcal an hour, 1.57 kg of coke, 11.3 t a year.

Cost and payback, both ways

• Cost: Rs 0.85 lakh for the system, Rs 0.15 lakh to fit: Rs 1.00 lakh.
• At the report's 28.08 t and Rs 7,500 a tonne: Rs 2.11 lakh a year, payback under 6 months.
• At 11.3 t: Rs 0.85 lakh a year, payback about 14 months. Still quick.
• The report found it suits about 25 of Pali's 100 stenters; at the time one process house had it.

Do not count it twice

Exhaust humidity control is booked the same way, as faster cloth for the same heat. On one stenter the two savings overlap, so measure coke per thousand metres after each change rather than adding the reports together.

CO2 from the coke saved, one stenter

• Report's case: 28.08 t x 3.17 = 89.0 t CO2
• 3% speed case: 11.3 t x 3.17 = 35.8 t CO2
• The report says 76 t
• No electricity saving is claimed

Pet coke at the IPCC 2006 default of 97,500 kg CO2 per TJ at 32.5 GJ a tonne, an estimate. A lab carbon analysis of your own coke gives a firmer figure.

What Senseible does here

Senseible reads pet coke invoices and electricity bills into monthly records linked to each bill, with CO2 for the power. It has no pet coke factor, so apply the IPCC figure above to the tonnes. At Rs 1 lakh you may not need a loan; if you do, the green loan check lists the papers.

• Green loan readiness check
• Stenter exhaust humidity control: saving
• Thermopac air preheater: pet coke saved
• Pali hand and power process units

Sources: BEE, Detailed project report: residual moisture measurement and control system in stenter, Pali textile cluster (2010, SAMEEEKSHA), IPCC 2006 Guidelines, Volume 2 Energy, Tables 1.2 and 2.3

Last reviewed 2026-11-01. Report figures are from a BEE SME programme project report; costs and paybacks are at 2010 prices. Check today's coke price and a current quote.