What does replacing furnace oil with a biomass gasifier do in a galvanizing furnace?

BEE's Howrah report swaps 162,000 litres of furnace oil a year for 756 t of wood and 41,400 kWh. Fossil CO2 falls by about 440 t a year; the wood's own CO2 is biogenic and reported separately. Cost Rs 40.71 lakh, saving Rs 28.07 lakh, payback 1.45 years at 2010 prices.

The furnace BEE costed

• A 6.8 m x 0.9 m x 0.9 m zinc furnace holding the vat at 490 C, burning 90 litres of furnace oil an hour.
• 6 hours a day, 300 days: 162,000 litres a year. Measured efficiency about 17%.
• Proposed: a wood gasifier rated at 1,237,500 kcal an hour, up to 450 kg of wood an hour, with 23 kW of fans and pumps.
• The furnace is rebuilt with a producer gas burner; that rebuild is Rs 6 lakh of the Rs 40.71 lakh.

Where the Rs 28.07 lakh comes from

• Oil saved: 162,000 litres at Rs 32 = Rs 51.84 lakh.
• Wood: 420 kg an hour, 756 t a year at Rs 2.50 a kg = Rs 18.90 lakh.
• Gasifier power: 41,400 kWh at Rs 5.60 = Rs 2.32 lakh. Operator: Rs 2.55 lakh.
• Net Rs 28.07 lakh against Rs 40.71 lakh: 1.45 years.
• Two slips in the report: its summary says 16.2 lakh litres where the tables show 1.62 lakh, and its payback text quotes Rs 40.17 lakh where the cost table adds to Rs 40.71 lakh.

Get the wood rate in writing

The report sizes the wood by matching the oil's heat one for one: 945,000 kcal an hour divided by 2,250 kcal a kg of wood gives 420 kg. That leaves nothing for losses in the gasifier. If wood use runs 25% higher, 945 t a year, the saving falls to about Rs 23.35 lakh and payback stretches to 1.74 years. Ask the supplier to guarantee kg of wood an hour at your furnace load, and check how wet your wood is.

CO2 counted properly

The report gives no tonnes, only that sustainably sourced wood is net zero. Count it in three parts: the oil CO2 that stops, the gasifier's grid power that starts, and the methane and nitrous oxide from burning wood, which stay in Scope 1. CO2 from the wood itself is biogenic: report it separately, outside the scopes, and keep weighbridge slips showing where each load came from.

One galvanizing furnace, one year

• Before: 162,000 litres x 2.97 = 481 t CO2
• After, power: 41,400 kWh x 0.675 = 28 t CO2
• After, wood methane and nitrous oxide: 7.12 TJ x 1.9 t per TJ = 13.5 t CO2e
• Fossil cut: 481 minus 28 minus 13.5 = about 440 t CO2e a year
• Biogenic CO2 from the wood, reported separately: 7.12 TJ x 112 t per TJ = about 800 t

Furnace oil at 2.97 kg CO2 a litre and grid at CEA's FY 2025-26 factor. Wood at the report's 2,250 kcal a kg, so 756 t carries 7.12 TJ; IPCC 2006 defaults of 112,000 kg CO2, 30 kg methane and 4 kg nitrous oxide per TJ, with AR6 warming potentials of 27 and 273. Estimates.

What Senseible does here

Senseible reads furnace oil invoices and electricity bills into monthly emission records, with furnace oil at 2.97 kg a litre. It has no wood factor, so add the wood lines worked out here from your weighbridge slips. At Rs 40 lakh, run the green loan check before you approach a lender.

• Green loan readiness check
• Galvanizing furnace: coal to wood gasifier
• Air preheater on a galvanizing furnace
• Biomass boilers: methane stays in Scope 1
• Howrah galvanizers and CBAM

Sources: BEE, Detailed project report: biomass gasifier replacing furnace oil based furnaces, Howrah galvanizing and wire drawing cluster (2010, SAMEEEKSHA), IPCC 2006 Guidelines, Volume 2 Energy, Tables 1.2 and 2.3, IPCC AR6 Working Group I, Chapter 7, global warming potentials (methane 27.0 non fossil; nitrous oxide 273), GHG Protocol Corporate Standard (biogenic CO2 reported separately from the scopes), CEA, CO2 Baseline Database for the Indian Power Sector, version 22.0 (FY 2025-26 grid factor)

Last reviewed 2026-11-01. Report figures are from a BEE SME programme project report; costs and paybacks are at the report year's prices. Check today's fuel and power prices and a current quote before you rely on the payback.