Can we get more biomass from the forest? We asked this in an article a while ago and decided to have a closer look at the logistics around that. We visited a biomass harvester to find out more.
Biomass harvesting with a Bracke C16 felling head
The south Swedish company Svenssons Energiflis AB (Svenssons Energy Chips) is specialized in harvesting biomass from the forest. They take on thinning and take out both pulpwood and biomass with the same harvester, a Komatsu 911.
Thanks to a home-made quick switch system they switch between a Bracke C16 felling head for biomass and a Komatsu S92 harvester head. With this system, they can take on complete contracts where both normal harvesting, as well as biomass harvesting, is included. The switch is made in less than half an hour.
The Bracke C16.c felling head
The C16 felling head has a cutting solution that makes it unique. Instead of a shear, that most of the competitors use, the Bracke head is equipped with a disc that has a saw chain mounted on it. The chain doesn´t run in the track as on a saw bar. The whole disc rotates which makes it more like circular saw, but with a saw chain instead of teeth.
This cutting solution make the C16 very flexible as you can cut stems from just a few millimeters diameter up to 260 mm (approx. 10”) in one cut. Theoretically, twice the diameter could be cut if cutting from two or three directions, but the head is not built for handling such big trees.
The chain is removed with a chain lock with two screws. As the chain and disc rotate together, no lubrication of the chain is needed. Compared to traditional shear heads, the Bracke C16 cuts very quickly thanks to this solution.
The production capacity for the C16 head varies a lot depending on type of material. When measuring cubic meters chips per hour, it varies between 10 to 35 cbm per hour. As mentioned above this depends on the type of material. When harvesting thick, long stems, like approx. 20 cm diameter, the production can be very high.
Here is a film of the Komtasu 911 and the Bracke C16.c in action: