How much coal does a recuperator save on a coal-fired rolling mill reheating furnace?

In a Raipur case TERI reported in June 2026, an 8 t an hour coal fired pusher furnace saved 376 t of coal a year after a recuperator brought chimney gas from 672 C to 300 C and preheated air to about 200 C. It cost Rs 8.5 lakh and saved Rs 38 lakh a year.

Before and after

• Furnace: coal fired pusher hearth, 8 t an hour, no heat recovery.
• Flue gas at the furnace outlet before: 672 C. At the chimney inlet after: 300 C.
• Combustion air: from ambient to about 200 C at the recuperator outlet.
• Also done: insulation on the hot air header and on the line to the coal pulveriser, so the air arrives hot.
• Result: 376 t of coal a year, Rs 38 lakh; payback under three months.

Why it pays so fast

At 672 C the flue gas was carrying away heat you had already paid for in coal. A recuperator is a metal or ceramic heat exchanger that hands part of it back to the combustion air, so less coal is burnt to reach soaking temperature. TERI's Durgapur study puts the ceiling at up to 25% of fuel where flue gas leaves at 650 to 800 C.

Prove it to a lender or buyer

1. Log coal per tonne of rolled output for three months before installation, from weighbridge slips and the production register.
2. Record flue gas and preheated air temperatures on the same days.
3. Log the same for three months after, at similar output.
4. Keep the coal invoices behind every figure; a saving claimed without them will not survive a lender's check.

Where it shows up in CBAM

Reheating coal is a direct emission of a rolling mill, so for bars and sections sold toward the EU this saving lowers your own share of the embedded emissions. Your billets' emissions are unchanged.

The Raipur recuperator, CO2 (estimate)

• Coal saved: 376 t x 1.76 kg per kg = 662 t CO2 a year at Senseible's Indian coal factor
• TERI reported 786 t, about 2.09 t CO2 per tonne of coal; its factor is higher than ours
• Money: Rs 38 lakh / 376 t = about Rs 10,100 per tonne of coal, the price the saving implies

Case data from the SAMEEEKSHA newsletter, June 2026 (TERI). The unit is not named in the source. Indian coal 1.76 kg CO2 per kg.

What Senseible does here

Senseible reads coal purchase invoices and power bills into monthly CO2 per tonne rolled, so the before and after a green loan asks for comes from your own records.

• Check green loan readiness
• Recuperator fuel saving method
• Durgapur rerolling mills output and CO2

Sources: SAMEEEKSHA newsletter, June 2026: secondary steel case studies (TERI).pdf), TERI, Situation Analysis of Durgapur Secondary Steel Cluster, 2024 (SAMEEEKSHA)

Last reviewed 2026-11-01.