Wood pellets are supplied in a number of forms:
- Bulk, blown into a customer's store by a pneumatic delivery truck,
- Bulk, tipped into a customer's store,
- Small bags for hand-tipping into a hopper, typically stacked on a 1-tonne pallet, but smaller pallets or individual bags are available,
- Large bags (aka bulk bags or FIBC) that typically hold a tonne of pellets, for decanting by a number of means.
(1) and (3) are the most convenient and therefore the most common options.
Wood pellets may be supplied direct from the factory, or they may be taken first to an intermediate depot. The wood pellets can be bulk hauled to the depots relatively efficiently in articulated trucks. It is important to build substantial stock in the depots over summer, when demand for heating fuel is low, to fill the gap in winter, when demand exceeds the production capacity of the factories.
For the best results and value, the wood pellets should be screened to reduce the proportion of fines (particles of < 3.15mm width and length) to less than 1% at the point that they are loaded onto the truck or into the bags. Reference samples should be taken at this point.
The delivery truck carries a series of flexible pipes that are connected between the truck and the flange on the inlet to the customer's store. The pipes and flanges typically have an internal diameter of 100mm (4"). The delivery trucks typically carry Storz 110A and male Camlock connectors of this diameter, so the flange on the inlet should be equipped with a suitable Storz or Camlock connector to match.
A blower on the truck compresses and blows the delivery air down the pipes. Once the air is flowing, the driver opens a valve to allow the wood pellets to flow into the delivery pipe. The pellets are caught up in the air flow and blown into the customer's store. A high flow rate of wood pellets is typically associated with a lower level of degradation during delivery, because it indicates that a high "solids loading factor" was achieved.
To minimise the generation of fines during delivery, the wood pellets should be delivered at as high a pressure as possible. Pressurised tankers are therefore the delivery vehicle of choice throughout Europe. Tipper-blowers are sometimes used, but besides the lower delivery pressure at which they typically operate, fines are also created by the grinding action of the rotary valve that controls the flow of pellets into the delivery pipe.
If you want to be billed for the exact quantity measured at the time of delivery, you should make sure that your supplier's truck is equipped with Legal for Trade weighing equipment (i.e. certified accurate by Trading Standards). Legal for Trade weighing is most likely to be found on tankers, because the moving body makes accurate weighing difficult on tippers.
The delivery air must be released during delivery, or the pressure will damage the fuel store. Some fuel stores are designed to release the pressure passively (see the Storage & Handling section). But the majority are designed with an outlet that is too small (e.g. the same diameter as the inlet) for passive venting. These stores will require suction during delivery. Not all delivery trucks are equipped with suitable suction systems - again, check with your wood pellet supplier.
Bagged wood pellets
Bagged wood pellets are typically stacked and wrapped on pallets that weigh approximately 1 tonne. Pallet hauliers are usually used to deliver the pallets. Most pallet hauliers deliver to kerbside, and you will need to move the bags from there to wherever you intend to store them. Some specialist bagged pellet suppliers offer a more personalised service that may include putting the bags into the store for you. Speak to your wood pellet supplier to find out what they offer, and expect to pay more for a more personalised service.