Canadian Biomass Magazine

Boilers Equipment Features Pellets
Measuring moisture: An in-depth look at the benefits of NIR moisture measurement


May 12, 2021
By Sarah Hammond

Topics
Measuring the moisture of wood chips. Photo courtesy MoistTech.

There are two things manufacturers and producers have at the forefront of their agenda, especially in today’s economy: minimizing cost and increasing efficiency. Knowing where improvements can be made and implementing increasingly lean operating procedures creates immediate process line results. 

When it comes to wood fuel biomass, moisture is vital for minimizing cost, properly operating biomass boilers and genuine fuel load assessment. Near-infrared (NIR) technology is a great non-contact way to measure moisture content, immediately improving the product and overall efficiency of the plant. 

Why measure moisture?

  • Reduce dryer usage and energy costs
  • Proper control of the infeed and dryer exit
  • Consistency of your final product
  • 100 per cent product inspection

Moisture control becomes crucial in wood and biomass products as excess moisture not only affects the product but also the equipment, energy usage, production efficiency, down time and more.

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Wood fuel boilers are optimally designed to operate with fuel that has a limited moisture range content. Fuel outside of the boiler’s tolerated moisture range can lead to multiple inefficiencies, increased emissions, and even errors in the control system. Knowing and maintaining the moisture content is essential to production efficiency and provides multiple immediate benefits. 

Instant results
Introducing lean manufacturing principles can allow operating personnel to hone in on best practices and top product quality. By implementing moisture monitoring, processing, and manufacturing, plants can produce large savings in a short amount of time. 

Wood fuel is purchased based off weight, which is very susceptible to moisture changes, making it critical in product energy savings. If incoming fuel has a high moisture content, then producers may be overpaying for wood fuel and increasing the energy required for dryer operation. 

Moisture control technology in pellet plant operations is crucial in order to proactively avoid quality control issues. A product that is too dry can result in over-drying, causing a dusty, ambient environment that can result in a fire. Moisture control systems can not only provide immediate cost savings and product quality, but severely improve the safety of the plant as well. Pellet plants often see dry conditions that can create sparks and other fire-causing issues; implementing a system to measure moisture at multiple points of the production process can greatly reduce this risk. 

Dry products create avoidable risk, as do products that are too wet. The pelletizer requires a tolerated moisture range to ensure its efficiency. Excess moisture can cause the pelletizer to malfunction, resulting in significant product loss and downtime.

Moisture control provides immediate results by reducing transportation costs stemming from excess water, and less wear and tear on equipment from ash and dust build-up. It also prevents blockages on the conveyor, which results in boiler shut downs. 

When it comes to challenges faced by plant operators, moisture detection and control is one of the most crucial steps. If there is no current method of moisture measurement in the production process, a key opportunity for increasing efficiencies is being missed.

Ultimate efficiency
Do you currently have the ability to consistently measure 100 per cent of the product being produced? Installing NIR moisture sensors throughout the process makes this easily achievable. Proactive, immediate adjustments are easily made to ensure optimal manufacturing by line personnel while monitoring the process anywhere in the facility. 

Maximizing automation and increasing reliability by reducing costs is a major benefit for operating personnel and easily achieved through moisture monitoring. Moisture ranges outside of a machine’s tolerance can unravel important facets of the production process. Each phase of the manufacturing process runs more efficiently with accurate moisture content and leads to higher profits. Identifying and using the best methods can lessen problems such as warping, claims, checks and excessive transportation costs.

Why near-infrared?
Multiple moisture detection methods exist for industrial processing – but, not all technology is created the same. Radio frequency (RF), weight loss and probe methods have various factors that need to be considered as they can sometimes provide more of an educated guess than a reliable measurement that can be repeated. 

NIR technology does not have to be in contact with the product at all – in fact, it measures moisture approximately four to 12 inches away from the product. Non-destructive and precise accuracy also make NIR the No. 1 choice for moisture detection. 

NIR spectroscopy and imaging provide fast, nondestructive analysis of the chemical and physical information in the product. When light hits a product, it interacts in various ways; transmitted light will pass through while backscattered light will reflect from the product back to the sensor. Absorption is key to NIR analysis. 

By implementing a NIR moisture sensor, wood and wood fuel product manufacturers can adjust moisture levels based on real-time information, thereby reducing raw material and fuel costs, as well as producing higher yields and more uniform products. NIR offers clear advantages over traditional methods, such as ease-of-use, elimination of hazardous chemicals, and increased efficiency of product testing. NIR analysis eliminates all manual steps of collecting, drying, and accurately weighing samples.

Proactive avoidance
Continuously monitoring moisture content leads to proactive avoidance of potential issues caused by out-of-tolerance moisture levels. Delivering the highest quality product by utilizing NIR moisture detection systems ensures the highest quality of accuracy and repeatability. The sensors are insensitive to material variations such as particle size and material height/colour; provide continuous, reliable readings with zero maintenance; require one-time calibration; are non-contact; and feature a non-drift optical design. Adjustments are made on-the-fly, producing instant measurements, improving performance, reliability, and consistency. •


Sarah Hammond is the Florida-based marketing manager for MoistTech, producing content tailored to the needs of manufacturers looking to increase efficiency. Contact MoistTech to see how proper moisture measurement and control can affect your production line at info@moisttech.com or 941-727-1800.