Writing a shell charcoal feedstock specification for activation
An activated carbon plant is only as predictable as the charcoal it feeds in. Yet many purchase orders for shell charcoal still say little more than “coconut shell charcoal, lump, good quality”. This note is for the technical buyer who wants a one-page charcoal feedstock specification that a supplier can answer line by line. It also shows, for each line, what Kora publishes today and what it does not. Kora supplies charcoal and charcoal powder; it does not make or sell activated carbon.
Why the charcoal feedstock specification belongs to you
The charcoal is an input, and what you can accept depends on your own furnace, activation route and the product you sell. A limit that suits one plant may be wrong for another. So write the specification from your process backwards: start with what your line tolerates and what your customers measure on the finished product, then translate that into limits on the charcoal.
The template
Use one row per property. Fill the “limit” column from your own process, and the “method” and “basis” columns before you sign.
| Property | Limit (yours) | Method | Basis |
|---|---|---|---|
| Fixed carbon | as received / dry | ||
| Volatile matter | |||
| Ash | |||
| Moisture at loading | as received | ||
| Size range and spread | |||
| Hardness | |||
| Foreign matter (soil, fibre, uncarbonised shell) | |||
| Lot size and identification |
What each row is for
Fixed carbon tells you how much of the charcoal is the carbon you want to work with. Kora publishes at least 70 % for lump charcoal.
Volatile matter describes what leaves the charcoal when it is heated, and it affects how the charcoal behaves in the furnace. Kora publishes no figure. Two academic studies seen in summary give a flavour of the range: one reports volatile matter around 25 % with fixed carbon near 74 % for a charcoal made at 400 °C, and another reports about 15 % volatile matter with fixed carbon near 84 % at 350 °C. These are experimental values from other charcoals, not trade specifications and not Kora results. Use them only to see why you must set your own limit.
Ash matters when ash in the charcoal carries into the finished product. Kora publishes up to 5 % for lump charcoal.
Moisture at loading affects weight, handling and storage. Kora publishes up to 10 % for both lump and powder.
Size range and spread decides whether the charcoal fits your feeding system and how much fines you will have to deal with. Kora publishes no size figures for lump, and the powder mesh is to order.
Hardness shows how well the charcoal survives handling and conveying before it reaches the furnace. Kora publishes no figure.
Foreign matter is the clean-up of the shell before and after carbonising. No figure is published; ask how it is controlled.
Lot size and identification lets you trace a problem to a batch. Kora issues a certificate of analysis (COA) with each shipment, and per lot for powder.
The question of basis
Every percentage on the table needs a basis. A fixed carbon of 70 % as received and 70 % on a dry basis are different charcoals. A supplier who cannot tell you the basis has not yet thought about your use.
How to use the template with Kora
- Send the filled template, even with some blank rows, together with your intended volume and port.
- Ask Kora which rows it can answer from existing data and which need a laboratory report.
- Request a sample and the report for the properties Kora does not publish: volatile matter, size spread and hardness.
- Compare the report with your own test on the sample.
- Turn the agreed limits into the contract specification, with the method and basis.
Next step
If you want to see the published figures before you write, open the lump charcoal feedstock page. When you are ready, send your template or your questions through the contact page. The first reply comes within two business days.
Questions buyers ask
Which properties belong in a shell charcoal feedstock specification?
List fixed carbon, volatile matter, ash, moisture at loading, size range and spread, hardness, foreign matter, and lot size with identification. Give each row a limit from your own process, a test method and a basis, either as received or dry.
What limits does Kora publish for lump shell charcoal?
Kora publishes fixed carbon of at least 70 per cent, moisture up to 10 per cent and ash up to 5 per cent for lump charcoal. It publishes no volatile matter, size or hardness figures, so ask sales for a sample and a laboratory report covering those.
Why must a charcoal specification state whether a percentage is as received or dry?
Moisture changes the weight, so 70 per cent fixed carbon as received and 70 per cent on a dry basis describe two different charcoals. Write the basis beside every figure and ask the supplier to confirm it before you sign.
Can I borrow a volatile matter limit from published academic studies?
No. The studies seen in summary reported roughly 25 and 15 per cent volatile matter on other charcoals made at different temperatures. Those are experimental values, not trade specifications and not Kora results. Set the limit from what your own furnace tolerates.