A comparision of on-line near Infrared, stand-alone near Infrared, and a rapid heating/scale unit in the drying of Oriented Strand Board (OSB) and Oriented Strand Lumber (OSL)

Mike Jacobson
Mentor: Steve Shaler
FBRI 2008

Abstract

The drying of wood to a low moisture content of 4 to 8% is an important process in the manufacture of Oriented Strand Board (OSB) and Oriented Strand Lumber (OSL). Continuous on-line monitoring of the moisture level is practiced in all commercial facilities. This project will utilize three moisture sensors (on-line near Infrared, stand-alone near Infrared, and a rapid heating/scale unit) available in the AEWC OSB pilot line.

Specifically, the student will:

• Conduct a literature review of the principles of near IR (NIR) moisture detection. Literature will be obtained from the library and online sources. Upon completion of reading and reviewing several pieces of literature, I hope to understand the use of NIR devices for moisture content measurement in wood.

• Learn the operation of the three moisture sensor units (Process Sensors Corp. MCT 300-WP and MCT 600, OHaus MB-45 Moisture analyzer). Equipment setup and training will be conducting to familiarize me with the equipment. These three devices are what I’ll mainly be using to conduct my research.

• Conduct a round-robin analysis of wood moisture with the units to determine the accuracy and correlation of the three devices. Statistical analysis will be done to reveal the variability and accuracy of each device when compared to known accurate moisture detection methods (oven-dry method).

• Use the on-line near IR unit in conjunction with the Koch Bros. conveyor strand dryer to monitor moisture loss in Aspen strands. This part of the experiment resembles a set-up that may take place in an OSB mill. The information and knowledge gained during the first part of the research will help me complete this objective.

• Establish relationships between conveyor dryer settings (speed, dryer temperature) and initial strand moisture content on final moisture setting. This will include the collection of time-series data and the presentation of control-chart information. The computer attached to the system, along with other statistical tools, will allow me to establish relationships between conveyor dryer settings. This information will reveal what settings result in maximum efficiency in drying Aspen strands at several different moisture contents.

Time permitting, the developed techniques and protocol will then be used to determine whether the extraction of hemicelluloses from wood strands prior to drying (a separate research activity looking at OSB quality) impacts the drying rate, energy requirement (due to higher wood moisture content after extraction), and accuracy of the near IR units.

As a result of the project, the student will learn about principles of near IR sensors, experimental design, process control charts, data presentation, and drying energy requirements (wood requirements and drying unit requirements).

Interview with Lucas, Zach and Mike on July 17, 2008