The shell you pay to dispose of is the steam you pay to buy
A cashew factory already owns its fuel.
Every tonne of raw cashew nut leaves 550 to 650 kg of empty shell, at 4,800 kcal/kg and under 3 % ash. Fired back into the factory’s own boiler it produces the process steam the plant would otherwise buy as LPG — roughly 150 kg/h of shell for a 1,000 kg/h boiler.
Indicative price of a biomass burner, Ex-Works (EXW): USD 1,050–12,750
Shipping, customs clearance and local duties are extra. The final price depends on the configuration and is fixed in the written quotation.
Where the steam goes in a cashew plant
Steam is not incidental to cashew processing; it is the process. Raw nut is steam-conditioned before shelling so the kernel releases cleanly, and kernels are humidified again after drying so they peel without breaking. Both duties are continuous through the shift and both want saturated steam at a held pressure.
A plant that buys LPG for those duties is paying twice over: once for the gas, and again to have the shell taken away. The shell arrives at the same rate as the nut, in the same building, every day the line runs.
The arithmetic of a closed loop
The shell yield is what makes the loop close rather than merely reduce the bill. These figures are the published properties of empty cashew shell, not a claim about any particular factory.
| Parameter | Value |
|---|---|
| Shell yield per tonne of raw nut | 550–650 kg |
| Calorific value | 4,800 kcal/kg |
| Ash | 1–3 % |
| Moisture as received | 4–8 % w.b. |
| Volatile matter | 80–83 % on a dry basis |
| CNSL calorific value | ≈ 11,380 kcal/kg |
| Shell to fire a 1,000 kg/h boiler at 10 bar | ≈ 150 kg/h |
| LPG displaced at that duty | ≈ 60 kg/h |
Why cashew shell needs a burner built for it
The difficulty is not the energy value, which is better than most bought fuel. It is the cashew nut shell liquid — corrosive, and at about 11,380 kcal/kg it volatilises early and lays down tar in an ordinary firebox. A grate designed for wood chip will foul on shell within a season.
The staged pyrolytic chamber is built around that fraction specifically: the fuel gasifies sub-stoichiometrically and the gas is burned out above 900 °C at the throat, which is what stops the CNSL condensing anywhere it can accumulate. That is the whole reason a cashew-specific burner exists.
What it means for the region
The cashew processing industry in Côte d’Ivoire, Ghana, Nigeria and Benin is large, concentrated and growing, and almost all of it has the same two line items: bought thermal fuel, and shell disposal. Those are the same line item written twice.
This is also the application the company has actually built. It is worth being precise about what that does and does not prove — the burner works at industrial scale on cashew shell at a customer site, and the drying side of the business has still never been built.
The reference installation
A 900,000 kcal/h cashew shell burner fires the steam boiler at Premium Cashew Commodities Limited in The Gambia, serving the factory’s process steam on the empty shell the factory produces itself. This is exactly the loop described above, closed on a real site.
It is the company’s one commissioned installation. We publish its configuration, its application and its fuel; we do not publish its measured efficiency, steam output or consumption, because those belong to the operator.
The site has a page of its own, with two films: the PCCL installation in The Gambia.
Specifications
| Parameter | Value |
|---|---|
| Burner range | 200,000–900,000 kcal/h |
| Design fuel | Empty cashew shell, 4,800 kcal/kg, 1–3 % ash |
| Steam pressure range | 8–10 bar |
| Scope | Burner and firing system; the boiler is the buyer’s |
| Primary combustion | Sub-stoichiometric, lambda ≈ 0.4 |
| Secondary combustion | Above 900 °C with excess oxygen |
| Warranty | 12 months from date of shipment |
The engineering is set out on the biomass steam boiler firing page and the equipment on the cashew shell burner. Shell is also the design fuel for drying — see tree nut and oilseed drying and industrial mango drying system.
Where this equipment is used
The same equipment is specified across several product classes. These are the ones it is configured for most often:
tree nut and oilseed drying, industrial mango drying system and fruit and vegetable drying.
Each of those pages carries the drying parameters, cycle times and quality targets for that product class.
Frequently asked questions
Will my own shell cover my own steam demand?
It depends on your shelling rate. A tonne of raw nut leaves 550 to 650 kg of shell, and a 1,000 kg/h boiler burns about 150 kg/h. A plant shelling a tonne an hour is comfortably in surplus; a much smaller one should plan for a supplementary residue rather than assume the loop closes.
What happens to the CNSL when the shell is burned?
It is burned out, not condensed. Cashew nut shell liquid carries about 11,380 kcal/kg and volatilises early, which is why it tars an ordinary firebox. The staged chamber gasifies the fuel and burns the gas above 900 °C at the throat, so there is nowhere cool enough for it to lay down.
Is shell worth more sold than burned?
Sometimes, and it is worth checking rather than assuming either way. Where a CNSL extraction market exists locally the calculation changes. Where it does not, shell is a bulky acidic waste with a disposal cost, and 4,800 kcal/kg of it arrives free at the same rate as the nut.
Do you have a cashew steam installation running?
Yes — one. A 900,000 kcal/h shell burner fires the steam boiler at PCCL in The Gambia on the factory’s own shell. It is a boiler application: no drying line has been built anywhere yet, and we do not publish measured performance from that site because it belongs to the operator.
Work out whether your shell covers your steam
Send us your raw nut throughput and your steam duty, and we will run the shell balance against them before anything is quoted.
Request the arithmetic