It may not be as glamorous as a bank of solar photovoltaic arrays or a windmill park gracefully extracting energy from shifting air masses, but simply improving the efficiency of biomass combustion may well represent a more significant alternative to fossil fuels. About 11 to 14 percent of all the energy used worldwide comes from plant-based sources such as wood chips or energy crops, so even small gains can add up to big savings.

Mantex, a Swedish start-up company, has developed a new instrument that can help boost the output of industrial plants burning biomass for heat. And the story doesn’t end there: the Mantex technology also identifies pollutants in the raw materials fed into industrial processes such as paper mills, reducing harmful effluents and cutting expensive downtime.

The Mantex Flow Scanner analyzes the chemical composition of wood chips and other biomass fuels. CEO Erik Odén.

The Mantex Flow Scanner analyzes the chemical composition of wood chips and other biomass fuels. CEO Erik Odén.

The Mantex Flow Scanner, which is initially being marketed to operators of wood-burning power generators, district heating plants and pulp and paper mills, provides instantaneous analysis of the chemical composition of vast streams of incoming raw materials. The most important component for these industries is the precise water content of biomass fuel, because proper combustion requires either consistent moisture levels or adjustments to burners as the water content varies.

The traditional way to measure water content is to weigh a sample of the fuel, dry it for a few hours in an oven, and then weigh it again. The drawbacks are obvious: this approach takes far too long, and only a tiny fraction of the raw material is tested, so variations within a given delivery may go undetected. The Mantex solution uses X-rays to scan tons of material as it passes by on a conveyor belt, measuring photon absorption to deliver a real-time analysis.

Absorption fingerprints

“Everyone knows that X-rays can be used to show differences in the density of human tissues,” says Erik Odén, CEO of Mantex. “That’s how medical imaging has been done for decades. Luggage screening at airports works on the same principle.

“We’re using X-ray technology in a completely different way. Each substance has a unique capacity to absorb photons of different energies. Knowing the photon absorption fingerprint of various substances, we light up the raw material with photons of different energy levels. By looking at how much is absorbed we can calculate the amount of each substance present in the sample.”

Mantex sees a huge market just among operators of industrial processes that involve burning biomass for heat, but Odén says he has identified a number of other applications for the technology. “Many processes require mixing chemicals according to quantities of dry substance. Say you’re making masonite sheets, where you mix glue and ground wood fiber. It’s hard to get the quantities exactly right if you don’t know the composition of the incoming material.”

Other potential applications for the Mantex scanner include:

  • Paper production: Determine precise dosing for chemicals such as white liquor, reducing waste and pollution. Determine the dry substance in the pulp.
  • Agriculture and forest products: In setting prices for agricultural and biomass commodities, buyers and sellers alike need to be able to measure dry weight.
  • Sawmills: The Mantex instrument can help sort incoming raw timber for best use as either construction material or fuel and scan the moist content in the logs so that the energy-consuming drying process can be optimized.

“Anytime you’re taking a raw material from the plant kingdom and refining it into a product, it’s important to know the chemical composition.” Odén says. “Things that grow in nature are not homogenous, but industrial processes perform best when the raw materials are as consistent as possible.

“Our scanners can also be used to identify pollutants,” he continues. “That may be unwanted chemicals that can throw sensitive processes out of balance and lead to negative environmental impacts, or dangerous objects like spikes in timber entering a sawmill.”

In addition to the large Flow Scanner designed for in-process testing, Mantex has developed a desktop version intended for batch analysis of small samples.

Article published in August 2009