Biomass Burner for a Boiler or a Dryer

What is shared

The combustion core does not care what it is heating. Fuel enters a sub-stoichiometric chamber at a lambda near 0.4 and pyrolyses; the resulting gas is burned out above 900 °C at the throat with secondary air. The fuel handling — store, conveyor, surge hopper, metering screw — is the same, and so is the de-ashing routine.

The capacity range is the same too, 200,000 to 900,000 kcal/h, and so is the fuel envelope. A processor who has one duty today and the other tomorrow is not choosing a different supplier or a different technology.

What differs after the flame

A boiler wants the flame in a furnace tube, surrounded by water. Heat moves by nucleate boiling on the outside of the tubes, gas leaves at around 200 °C having entered at around 1,050 °C, and the output is dry saturated steam at a held pressure. The boiler itself is not ours: we supply the burner and the firing system, and the burner’s job ends where the boiler’s begins.

A dryer wants the flame kept away from the product entirely. The heat crosses an exchanger into a clean air stream, arrives at the chamber at a controlled 50 to 150 °C, and is blown over the load at 2.0 to 3.0 m/s. That exchanger costs about 22 % of the heat and is what makes the arrangement usable for food.

	Boiler duty	Drying duty
Heat goes into	Water, through the furnace tube	Air, through a heat exchanger
Output	Saturated steam at 8–10 bar	Clean air at 50–150 °C
Control signal	Steam pressure transmitter	Chamber temperature setpoint
We supply	Burner and firing system only	Burner, generator and chambers
Typical worked case	1,000 kg/h steam on ≈150 kg/h of shell	4,968 kg fresh mango on ≈600,000 kcal/h

Control is where the two feel different

A boiler burner trims against a pressure transmitter: pressure falls, firing rate rises. The response has to be quick because a steam load can step in seconds, and thermal mass in the combustion chamber is the enemy of that.

A dryer burner trims against a chamber temperature setpoint over a cycle of 16 to 30 hours, where nothing steps quickly and thermal mass is a friend — the double chamber exists precisely to buffer load swings and hold the delivered air in a narrow band.

Which one a cashew processor actually needs

Often both, and usually steam first. Raw nut is steam-conditioned before shelling and kernels are humidified after drying, so steam is continuous through the shift. Drying is seasonal by comparison, and it is the part of this business that has never been built.

The shell arithmetic works for either. A tonne of raw nut leaves 550 to 650 kg of shell at 4,800 kcal/kg, which is more than enough to fire a 1,000 kg/h boiler at about 150 kg/h — and the same shell would otherwise be a disposal cost.

Frequently asked questions

Can one burner serve a boiler and a dryer?

Not simultaneously and not well. The two want different control responses and different downstream equipment, and a burner trimming against steam pressure cannot also hold a 65 °C air setpoint. Two burners sharing one fuel store and one handling system is the arrangement that actually works.

Which duty is more efficient?

Boiler duty, and by a wide margin. A boiler reaches around 80 % on gross calorific value, where a drying line reaches around 0.40 fuel-to-evaporation once the exchanger, the ducting, the envelope and the exhaust are counted. The dryer is not worse engineering — it is carrying water out of a chamber, which the boiler does not have to do.

Do you supply the boiler?

No. We supply the burner and the firing system across the 200,000 to 900,000 kcal/h range, and the boiler is yours — existing or separately procured. On drying duty the scope is wider, because the generator and the chambers are ours as well as the burner.

A biomass burner for a boiler, or for a dryer