Finnish researchers develop new system for drying wood chips used for bioenergy

A new way of drying wood chips for bioenergy has been developed by Finnish researchers.

The artificial dryer, in the form of a shipping container, is developed by Finnish company SFTec  and the Natural Resources Institute Finland (Luke).

The project highlights the complexities of drying technology. A wide range of artificial dryers on the market run into technical challenges especially when it comes to eliminating moisture in fuel chips, which affects heating value and the amount of energy obtained from the chips. Damp forest chips burn imperfectly, which also means that emissions increase.

Forest chips are used in heating buildings, in small-scale district heating plants and in heating and power plants for towns and industry. They are collected from young forests, from logging residues in regeneration fellings and from stumps and rot damaged trunks.

The first drying test has been carried out using stem wood chips.

Researchers are currently calculating supply chain costs based on artificial drying and comparing them with the traditional approach.

According to SFTec, the quality of fuel chips varies, as drying of the raw material is dependent on the weather.

There may be interruptions in the operation of heating plants making it necessary to use other energy sources, such as oil. Moisture in fuel chips is detrimental, as it affects heating value and the amount of energy obtained from the chips.

“The higher the moisture content of fuel chips, the less energy they provide,” said Juha Laitila, principal research scientist at Luke.

Damp forest chips burn imperfectly, which means that emissions increase.

Weight limits for road haulage have changed and transportation of freshly felled wood has become more cost efficient.

There is new demand for drying technology relating to heat production.

Luke is involved in a project to develop an artificial dryer for drying forest chips.

Its operating prerequisites and cost benefits will also be evaluated.

Last year, SFTec Oy, a company located in Oulu, constructed a dryer based on its own technology in a shipping container.

“There are a wide range of artificial dryers on the market. The advantage of our dryer lies in that relative to its size the equipment is efficient, easily moveable and it is suitable for various materials, including wood chips,” said managing director Jani Isokääntä.

The first drying test has been carried out using stem wood chip.