Rapid moisture analysis of wood-based materials at Stora Enso, Oulu

The industry has traditionally used standardized oven drying to determine the moisture or solid content of wood chips and biofuels. Its downsides include the slowness of measurement and the loss of wood extractives. For a long time now, there has been a need for a measurement system that is both quicker and better suited to real-time quality control.

A few years ago, Valmet developed the fast and accurate Valmet MR analyzer for the specific purpose of measuring moisture in wood-based material. The aim of product development was to create a measurement device that would replace the slow oven drying method. The device utilizes magnetic resonance technology to determine the actual amount of moisture within the sample. The same accurate technology is also utilized in medical magnetic resonance imaging.

Operators determine moisture samples

Stora Enso Oulu was among the very first plants to acquire the Valmet MR analyzer. The device made it possible to perform analyses quickly near the specific section of the process. The solid content of wood chips is determined by the employees in wood processing. The user-friendly analyzer has received high praise from them.

The plant utilizes the device in measuring its own and purchased chips, bark, and the sludge from the biological treatment plant.

- “This quick and easy method provides the employees with a tool for determining the solid content according to the situation. We do not need to transport the samples to the laboratory, and we do not have to wait 24 hours for the results,” says Kalle Kärnä, Production Engineer at the debarking department.

The samples are identified by barcodes. The analyzer’s measuring results are transferred directly to the plant’s data system.

The device is also used for monitoring the operation of the sewage sludge press. The analyzer has also proved very useful on the sludge press during trial runs.

Measurement data as part of the purchasing process

One of the analyzer’s advantages is the ability to measure large numbers of samples in a short period of time. The higher measurement frequency made possible by the device provides a more accurate result of the moisture content of deliveries. Thanks to the system connection, the results are immediately available to the people who need them.

Valmet MR is now an officially accepted method in quality control.

*) Note!: Product and company names are changed while Valmet acquired Metso’s Process Automation System business and products on April 1st 2015.