Biomaterial Moisture and Dry Density Analyzer

W-Mod Analyzer in a nutshell

W-MOD measures moisture and density of various homogeneous biomaterials. such as wood chips, sawdust, peat, and bark.

Versatile: W-MOD can be installed in a laboratory for manual use, on a production line with an automatic sampler, or cross belt for full material flow analysis.

Modular: Number of optional modules such as elemental analysis, gamma module provide additional measurement information and added value.

Robust: Measurement is not affected by chip size or density, wood species, temperature, and water phase (liquid, snow/ice).

Service: NeutronGate service follows instrument diagnostics remotely and provides service before failures occur.

Key specifications

Accuracy: Dry wood density measurement accuracy <1 weight-% standard deviation with automated measurement every 10 minutes.
Measurement range: 30-80%.
Maintenance period: 1 year
Power requirement: 32A 240VAC 3-Phase
Interface: Ethernet, Modbus, 20mA current loop, and others on request
System weight: 400 kg (+ 1000kg radiation shielding)
Operating temperature: -40 – 45C
Operating humidity: 0-100%

Data generated

Main variables

Sample moisture (weight-%)

Accuracy of <1 %-point standard deviation.

Sample density (kg/l)

Accuracy of <1% standard deviation.

Energy content (J/kg)

For homogeneous materials, energy yield is related to moisture ans can be calculated based on moisture and dry mass.

Total dry biomaterial flow (ton/h)

With radiometric mass flow measurement, accuracy of <2% can be achieved.

Total water flow (ton/h)

With radiometric mass flow measurement, accuracy of <2% can be achieved.

Optional modules

Foreign material detection

Presence of harmful foreign materials such as sand, soil, rocks can be detected by use of gamma imaging module

Elemental analysis module

With comprehensive elemental analysis, ash-forming elements can be identified from material. Also process poisons, toxins, and corrosive materials can be detected from material flow via neutron activation analysis.

Example of an installation

W-MOD can be installed in various locations: It can automatically take a sampling flow from a belt, drop chute or silo, or it can be installed to a laboratory for manual use.

In a most typical setup, W-MOD analysis has three steps:

  1. A sample is collected. Discrete samples or continous sample flow is collected by sampling screw from a drop chute or silo. In cross belt measurement conveyor runs thru the instrument and whole material flow is measured.
  2. Moisture measurement. Neutron and gamma signal is used to derive the water and dry material density.
  3. The sample is returned to the main flow. Then, W-MOD will automatically collect a subsequent sample.
A diagram shows an example of B-MOD system installation. A side flow is taken from a silo and returned to conveyor belt.


Benefits vs. oven moisture measurement

Gravimetric (oven) measurement is the most conventional moisture measurement used. This refers to a measurement, where a small sample is dried in an oven, and the lost weight is accounted for the water.

Using gravimetric measurement as the basis of process control has three main flaws:

  • Inaccurate measurement: Small sample sizes yield inaccurate results. Drying also removes extractive agents, which increases results’ inaccuracy
  • Too long measurement: In most factories, drying takes 24 hours, which is too long to optimize processes.
  • Sparse data: As the data is inaccurate and measurement takes a long time, in most factories oven measurement is done rarely.

With our analysis, chip moisture can be measured every 10 minutes with under 1% accuracy, so the data can be used to optimize processes during the day. 

Benefit for pulp mills

Pulp mills can use W-MOD to achieve the following benefits:

  • Ensure price is paid only for dry wood.
  • Better wood-liquor balance, more stable process.

Benefit for biofuel plants

Biofuel plants can use W-MOD to achieve the following benefits:

  • Ensure price is paid only for dry wood.
  • Manage inventory better.
  • Know your fuel calorific value.
  • Measure amount of ash-forming elements.
  • Identify corrosive or toxic materials such as preserved wood or PVC plastic.
  • Detect sand, soil and rocks from biofuel.

Five reasons to choose our instrument

We acknowledge there are multiple other suppliers of wood chip moisture measurement. However, below five factors make our technology unique from the alternative technologies on the market. Thus, our W-MOD is the best option for factories, which want to optimize processes on a daily basis.

Surface water, snow and ice

All other technologies (X-ray, NIR, microwave) are more or less sensitive to snow and ice, as their signal depends on the electron configuration. In some cases, samples can be heated, but there is a risk of skewed sampling data due sample processing.

Our technology interacts on nuclear level so it is robust against errors caused by phase change or interference caused by other chemicals.

Bulk measurement

Some measurements, such as NIR, are surface-measurements. Surface measurements can be inaccurate, if sample surface is different from the volume of the material.

As we measure through full volume of a sample, our technology gives a more representative signal.

Care free

Other technologies need regular maintenance to ensure for example that antennas are not coated, or that an optical sensor is clean.

Our technology is robust to staining, so it requires minimal maintenance from factory personnel. NeutronGate maintains the instruments with minimal investment of time from user.

Heterogenous non-uniform material

Changes in material such as dry density variations, micture of materials such as bark, wood or different wood species can ruin the calibration for most competing methods.

As our technology interact on vull sample volume and on nuclear level measurement of heterogenous and non-uniform material is possible.

Additional variables

Most instruments only measure moisture. That is good, if moisture is the only variable needed to optimize a process.

According to our market survey, total mass flow is the most important for the process optimization, so we have integrated a radiation belt weigh to our system. Additionally, we can measure elemental information from material flow providing valuable information for process controll.

Aerial image of Kotkamills pulp mill. Usage by courtesy of Kotkamills.

Proven performance

We performed a pilot project at Kotkamills facilities in Kotka, Finland during 2020 and 2021. This pilot helped us prove W-MOD accuracy. During the pilot, W-MOD was subjected to temperatures between -20 and 30 C. Additionally, we measured samples with ice and snow.

Read more about the pilot here.

Additional information

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Interested on how our technology can benefit your business?

Contact us at: info@neutrongate.com