How much coke does an efficient 600 kg pit furnace save in brass melting?

BEE's Jagadhri design cuts a 600 kg brass pit furnace from 96 to 81.6 t of coke a year, saving 14.4 t, by rounding the pit and preheating the charge with flue gas. At the IPCC coke factor that is 43.5 t CO2, more than the report's 39 t. Cost Rs 0.95 lakh.

The furnace today

A rectangular pit lined with refractory and faced with red brick, coke fed from below and the sides, a 1 HP blower. It melts 600 kg a batch on 80 kg of coke, four batches a day for 300 days: 96 t of coke. Melt temperature was 1,021 °C, flue gas 500 to 550 °C, efficiency 11.4%, and about 20 kg of coke was left unburnt each batch.

Two changes, half the saving each

• Rounded corners: the pit shrinks from 0.312 to 0.297 m3, so 7.4% less coke fills the space around the crucible: 7.1 t a year.
• Waste heat recovery: flue gas cooled from 500 to 200 °C in an exchanger at 65% effectiveness preheats the charge: 7.81%, or 7.3 t a year.
• Together 14.4 t, 15%. The report also says efficiency rises from 11.4% to 13%, which alone would be about 12%; treat 15% as an estimate to measure.

Cost and payback

Rs 0.75 lakh for the furnace with heat recovery plus Rs 0.20 lakh for civil work. At the report's Rs 22,000 a tonne, 14.4 t is Rs 3.17 lakh a year: payback in under four months. If the real saving is half the estimate, payback is still about seven months.

Count the coke you burn

If unburnt coke is raked out and charged again, 80 kg a batch counts it twice. Work out CO2 from coke bought plus opening stock minus closing stock, which is also what a lender or buyer can check against invoices.

CO2 per year and per tonne of brass

• Before: 96 t x 3.02 = 289.9 t CO2
• After: 81.6 t x 3.02 = 246.4 t CO2
• Saved: 14.4 t x 3.02 = 43.5 t CO2 a year
• Per tonne melted: 133 kg coke (403 kg CO2) falls to 113 kg (342 kg CO2)

Coke at the IPCC 2006 default, 107,000 kg CO2 per TJ at 28.2 GJ per tonne, an estimate. Furnace figures from BEE's 2010 report.

What Senseible does here

Senseible reads coke invoices and electricity bills into dated monthly records linked to each bill. It has no built-in coke factor, so apply the IPCC figure above to the tonnes. The green loan check shows what a lender asks for on a furnace upgrade.

• Green loan readiness check
• Coke pit furnace to induction
• Jagadhri brass and aluminium cluster
• Oil crucible or induction for brass

Sources: BEE, Detailed project report: energy efficient pit furnace for brass melting, 600 kg, Jagadhri brass and aluminium cluster (2010, SAMEEEKSHA), IPCC 2006 Guidelines, Volume 2 Energy, Tables 1.2 and 2.3

Last reviewed 2026-10-31.