What does a coal gasifier save on a 100 tonne downdraft kiln in the Godavari refractory cluster?
In the Bureau of Energy Efficiency (BEE) Godavari report, a coal gasifier cuts a 100 tonne downdraft kiln from 140 to 106.67 tonnes of coal a batch: 666.7 tonnes a year over 20 batches, Rs 28.80 lakh after gasifier power, for Rs 62.17 lakh. Payback is 2.16 years.
How the report gets 33.33 tonnes a batch
- Today: 140 tonnes of coal at 4,200 kilocalories (kcal) a kg for a 90 tonne firing, 588 million kcal. The report puts total heat losses at 55%, so 264.6 million kcal reach the bricks over 8 days: 33.075 million a day.
- The gasifier is rated 2 million kcal an hour. At 70% use that is 33.6 million kcal a day, the heat of 8.00 tonnes of coal a day.
- At 60% gasifier efficiency it takes 13.33 tonnes of coal a day: 106.67 tonnes over 8 days, 33.33 tonnes less than 140.
The money
- 33.33 tonnes x Rs 4,500 = Rs 1.50 lakh a batch; 20 batches = Rs 30.0 lakh.
- Less Rs 0.06 lakh of gasifier power a batch, Rs 1.20 lakh a year: Rs 28.80 lakh.
- Cost Rs 62.17 lakh; 62.17 / 28.80 = 2.16 years. Net present value Rs 43.21 lakh, internal rate of return 29.19%, debt service coverage ratio 1.84.
What to check
The report says no unit in the cluster has a coal gasifier, so these are design figures, not results from a running plant. The saving rests on the 55% loss and 60% gasifier efficiency. Ask a supplier for coal per batch from a comparable running kiln.
Carbon dioxide (estimate)
- Coal saved: 33.33 tonnes x 20 batches = 666.7 tonnes a year
- At 1.76 tonnes of carbon dioxide (CO2) a tonne of Indian coal: 666.7 x 1.76 = 1,173 tonnes, before gasifier power
- The report says 1,200 tonnes, about 1.80 a tonne of coal
Coal at Senseible's Indian coal factor, an estimate. Heat and cost figures from the Bureau of Energy Efficiency (BEE) report at about 2010 prices.
What Senseible does here
Senseible reads fuel invoices and electricity bills into monthly records with carbon dioxide equivalent (CO2e), so coal bought before and after a gasifier is on record with its bills. The green loan check shows what a lender asks for.
- Green loan readiness check
- Godavari refractory cluster: coal and carbon
- Waste heat recovery on a downdraft kiln
- Refractory kiln: coal to biomass gasifier
Last reviewed 2026-11-04. Report figures are from a Bureau of Energy Efficiency (BEE) Small and Medium Enterprises (SME) programme project report; costs and paybacks are at the report year's prices. Check today's prices and a current quote before you rely on the payback.