The two new wood pellet entries are distinguished by a couple of factors. One entry contains wood pellets with additives and/or binders and the other does not. The other factor is the classification of the wood pellets in the International Maritime Solid Bulk Cargoes ( IMSBC) Code. Both wood pellet entries are classified as Group B and a material hazardous in bulk ( MHB). However, the wood pellets with additives/binders are classified as MHB(WF), ie when the wood pellet is wet, it can emit flammable gas. Wood pellets without the additives/binders are only classified as MHB (OH), ie having the hazard of oxygen depletion and increase of carbon dioxide and carbon monoxide in cargo and communicating spaces. One could attribute the different MHB classification to the additives and binders used in the wood pellets to improve their durability.

These products are increasingly shipped in bulk due to their popular demand as biomass fuel products in the renewable energy sector. 

The member was asking whether non-food grade corn starch and “lignins” are considered as additive and/or binder and whether there was a list available for permitted additives and/or binders to wood pellets . No information was provided in the IMSBC Code on these questions raised.  BIMCO asked the relevant government who made the original submissions on wood pellets to the IMO for assistance. Their response was that based on their understanding, lignins were not considered an additive or binder as it was a component that was naturally occurring in wood materials used for manufacturing wood pellets. They also advised that they do not have a list available on permitted additives/binders. The government concerned did not comment on “non-food grade corn starch”. 

Regarding lignins being a natural component seems to be correct, as information available on the internet says it as an organic polymer present in wood and important for the formation of cell walls leading to rigidity and enables the wood not to rot easily.  Due to the high pressure and friction of the press machine used to compress the wood mass to wood pellets, this caused the temperature of the wood to increase significantly thus plasticizing the lignins and forming a natural ‘glue’ that holds the pellets together as it cools. 

As for common binders used, they include starch (from corn or rice) , lime, fiber, molasses, natural paraffin, plant oil, lignin sulphate and synthetic agents based on information available on the internet.

BIMCO advice 

If you are planning to fix a shipment of wood pellets, it is advisable to find out first whether the wood pellets come with additives/binders or not in order to ascertain the proper classification of the cargo under the IMSBC Code and hence the correct carriage requirements to follow. 

Under our online BIMCO Solid Cargo database, there are certain synonyms used which can help to indicate if the wood pellets come with or without additives/binders. Please see wood pellets with additives/binders and wood pellets without additives/binders for more information. 

If they are wood pellets with additives/binders, you would have to check with the shipper/manufacturer what they are and check if the country of the port of discharge has any national or local legislation governing the permitted type of binders/ additives used for wood pellets, given that there is no official list available on permitted binders/additives.

Note also that only wood pellets without additives/binders can be exempted from having CO₂ fittings in the cargo holds as per MSC.1/circ.1395/Rev.2.