Moisture Measurement of Wood Chips

Using Microwave and Radiometric Technologies

Oak Ridge TN, USA & Bad Wildbad, Germany — A major pulp and paper producer processes both hard and soft wood chips at the same location, and had tried several on-line moisture systems (infrared, neutron backscatter, etc.) and nothing seemed to work.

They wanted to measure the moisture in their wood chips to control the addition of white liquor to their Kamyr digesters.There are three belts at this location, two for soft wood (mostly pine) and one for a hard wood mix.

Micro-Moist System (Berthold LB 456 MicroMoist with Density Compensation), and it was installed on the hard wood chip belt . This belt was chosen because they will run both types of wood on it.

Spiral horns were used as well as radiometric mass compensation. Over the next two months the Micro-Moist was operating on both hard and soft wood chips and data was collected for fine tuning the calibration.

After testing it was decided to have two separate calibrations, one for hard wood and one for soft.

The system operated without problem. The accuracy of the Micro-Moist on hard wood chips was better than ?? 1 %. Based upon initial results on soft wood, the expected accuracy would be between 1 to 1. 5 %, which is very acceptable.

The 4 to 20 mA signal from the Micro-Moist is connected to their distributed control system and is controlling the addition of white liquor to the digester.

They have improved their Kappa number by better than 0.2.

BERTHOLD TECHNOLOGIES‘ experience and know-how in physics and in techniques of highly sensitive detection of light, nuclear radiation and microwave frequencies, together with the use of modern electronics and software, allows them to maintain an excellent and long reputation as a competent partner in solving diverse and difficult measurement problems and as a supplier of innovative and up-to-date instruments of the highest quality and reliability.

Calmbacher Stra??e 22
D-75323 Bad Wildbad

Telefon (+49) 70 81-177-0
Fax (+49) 70 81-177-100

Berthold Technologies U.S.A. LLC
99 Midway Lane
Oak Ridge, TN 37830 USA

Phone: +1 (865) 483-1488
Fax: +1 (865) 425-4309