Can a small Villupuram rice mill replace its firewood paddy dryer with a gasifier, and what does it save?

It can, and TERI's Villupuram profile estimates that a biomass gasifier making hot air from husk or wood saves 30 to 50% of dryer fuel. Fitted to the district's 40 or so 2 tph mills, it would save about 900 toe a year, roughly 56 t of firewood equivalent per mill (estimate).

Why the small mills burn wood

In Villupuram's 4 tph mills, steam at about 8 kg per cm2 heats the air that dries parboiled paddy. The 2 tph mills mostly fire wood straight into a hot air dryer instead. Firewood meets about 20% of the district's mill heat, 5,640 t a year, and it is the one fuel they buy: about Rs 19.7 million a year across the cluster. A typical 2 tph mill uses 131 toe of heat and 8 toe of electricity a year.

What a gasifier changes

• Husk or wood is turned into producer gas, which burns cleanly and can be controlled, instead of burning the fuel directly.
• TERI's estimate: 30 to 50% less fuel for the same drying.
• It can run on husk freed up by boiler improvements, so bought firewood falls first.

Do the boiler at the same time

• Economiser and condensate return, feedwater up to 90 C: about 10% less husk. Across about 50 mills, 2,304 t of husk (744 toe), worth about Rs 28 lakh a year.
• Solar water heating for soaking water: about 421 t of husk (136 toe) a year.
• Insulate steam and hot water lines, and fit steam traps where the small mills have none.

What to record before and after

1. Firewood bought each month, with bills and weights.
2. Paddy dried, and moisture before and after the dryer.
3. Husk burnt and husk sold.
4. The same months a year apart, so a lender can see the change.

One 2 tph mill (estimate)

• If all firewood goes to the 40 small mills: 5,640 t / 40 = about 141 t a year each
• At 30 to 50% saved: 42 to 70 t of wood a year
• At the cluster's cost, Rs 19.7 million / 5,640 t = about Rs 3,500 a tonne: Rs 1.5 to 2.5 lakh a year
• TERI's figure: 900 toe / 40 mills = 22.5 toe each, about 56 t of wood equivalent at 0.4 toe per tonne
• Wood CO2 avoided, reported as biogenic: 22.5 toe x 41.868 GJ x 112 kg = about 105 t a year

From TERI's Villupuram profile (2014-15). The split of firewood between mills is an assumption; wood CO2 uses the IPCC 2006 default for wood. Your own bills give the real figures.

What Senseible does here

The green loan check shows what a lender wants before funding a dryer change. Senseible keeps your firewood, husk and power bills in one dated record, so the before and after comes from documents.

• Green loan check
• Red Hills vs Villupuram energy
• Biomass gasifier vs LPG furnace
• Biomass boilers still have Scope 1

Sources: TERI, Cluster profile: Villupuram rice mills (SAMEEEKSHA, 2014-15 data), IPCC 2006 Guidelines, Volume 2 Energy

Last reviewed 2026-10-31.