Wood Chip Moisture
Moisture Content Directly Correlates to Quality
Most chip purchasers weigh wet chips but pay chip suppliers based on dry chips delivered. To calculate the bone-dry tonnage delivered, a representative wood chip moisture content is applied to the wet weight of the chips delivered to the mill. MoistTech sensors can be installed at just about every location of incoming material feed; not limited to truck dumpers, stackers, and re-claimers.
Incoming wood from the yard storage will vary largely based on the supplier, weather, and season. Installing above the conveyed material allows plant control to monitor the moisture content instantly and accurately.
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Green Wood Chips
Green wood chips have been traditionally considered a waste product and have been historically used as a source for pulp used to make paper and as an organic mulch in landscaping. Neither use has required a tight control of green wood chips moisture.
Recently, however, green wood chips have become popular as a biomass fuel. As a fuel, it has forced exploding growth in the biomass furnace industry. To work most efficiently, furnace manufacturers have had to identify and define optimum green wood chips moisture. Fortunately, despite what might have been a difficult transition from a waste product to a biomass fuel, it is possible to control moisture in green wood chips with existing technology.
The energy available from green wood chips is directly proportional to the moisture in the chips. To make the fuel in green wood chips available, biomass furnaces must first convert the moisture in the wood chips to steam. The higher the amount of moisture in the wood chips, the more energy required to convert it to steam before the fuel is available. To ensure the efficacy of their furnaces, manufacturers build their furnaces to operate at a very specific range of green wood chips moisture.
Bark
Across all locations, the moisture content in the sapwood consistently exceeds that of the inner bark, which in turn surpasses the moisture content of the outer bark. When considering all sites and positions within the trees, the average moisture content in the inner bark ranges from 85.9% to
non-contact
Our equipment never comes into contact with the product, allowing for less waste
zero drift
Our sensors are guaranteed not to drift over time – which saves time and money
closed loop
Create a closed-loop process by tying a moisture sensor into your PLC. Full control over the line!
no recalibrations
We’ve mastered the art of moisture sensors – your unit will never need to be recalibrated for the same product twice!
Efficient Wood Chip Moisture Control
The loader operator finds the IR3000 to be extremely beneficial. This is because a sensor is installed on the screen infeed conveyor, while a large display is mounted outside for the operator’s convenience. The initial step involves screening the mixture of sawdust and wood chips to separate the fine chips from the coarse ones. The coarse chips are then ground to reduce their size, ensuring quick and uniform drying. Subsequently, they are mixed again for temporary storage.
Following a second screening to separate the fines from the coarse chips, the hammer mill is used to further reduce the size of the coarse chips. The output from the hammer mill, along with the fines, is mixed once more and stored in bins based on their moisture content. The sawdust is then conveyed into a sizable drum dryer, where the moisture level is decreased to less than 10%. Afterward, the sawdust is conveyed into a cyclone dryer, where high-speed swirling air eliminates additional water vapors and cools down the product. Typically, the IR3000 is mounted on the dryer outfeed to ensure that the moisture content remains at approximately 10%. If the moisture level exceeds 10%, the sawdust will be directed to a moist bin. Usually, the moist bins and dry bins are blended together to achieve the ideal moisture level before entering the pellet press. By utilizing the IR3000 on each of the bin outputs, additional information can be obtained to assist in the blending process.
Wood Chips for Paper
The wood utilized in paper production often arrives with a moisture content exceeding 60%. Without the use of advanced moisture meters at various stages of production, the risk of equipment blockages, product loss, and inefficient processes is significantly high. Managing such high moisture levels in the raw material requires precise control. Near-infrared (NIR) sensors provide instant moisture readings, eliminating the need to wait for time-consuming lab results and enabling real-time monitoring of the manufacturing line with greater speed and accuracy. In the paper industry, where high moisture levels demand close attention, real-time feedback is crucial for operational success.
As wood pulp (chips) mixed with chemicals enters the paper machine to form a web, the moisture content often remains above 60%. Monitoring moisture levels is essential to regulate vacuum pressure during water removal. If the web is too wet, it becomes fragile and prone to breakage, leading to process shutdowns for machinery cleaning or excessive strain on drying cylinders. Maintaining the appropriate temperature in these cylinders is crucial to reduce the moisture content from 20-30% upon entry to the required 5-7% for quality control standards. Incorporating NIR meters at this stage allows for precise, non-destructive measurements in real time. Data from these measurements can be leveraged through networked sensors to make automatic adjustments, optimizing the process, and enhancing final product quality and throughput.
Directly on the Production Line
Monitor your product continually by installing our wood chip moisture gauge a few inches above the conveyor belt. Even if there are small gaps in product flow, our sensor can still give accurate readouts.
Whether you choose to monitor your product manually or automatically, our state-of-the-art sensor can help you through the wood chip monitoring process. We also have developed real-time process measurement, which you can learn more about in our sampling technology section.
Our wood chip moisture sensor does well even in dusty environments. If your environment is extremely dusty, you can benefit from an Air Purge System, which will significantly help in keeping your sensor free of dust and reading accurately.
You may also need to monitor your sensor if it’s installed near high-heat areas, like a dryer outlet. You can choose to cool the sensor with air or water.
Contact
We offer service and support throughout the world for our moisture measurement sensors and would be happy to connect you with a rep in your area. Contact us today for more information!
Understand the Process
MoistTech sensors feature unique technology that can calculate measurements through the near-infrared region (NIR) of the electromagnetic spectrum, to accurately measure and control moisture from lab to line.