X-raying branches and tops

In Phase 2 of the EES program, Mantex has researched the suitability of an enhanced version of our qDXA technology to measure both moisture and energy content in forest residue such as bark, branches and tops (Swedish: GROT). These residual products are becoming increasingly important for the bio energy sector as a viable source of energy.

The challenges in accurately analysing these materials is made greater due to their inhomogeneous composition compared to normal wood chips. Both moisture and energy levels can vary greatly based on the type of trees, season, transportation and storage processes.

So far the only accurate methods to analyse moisture and energy content are conventional; oven-dry and weigh the sample to find the water content, and then burn it to measure the energy and ash content. Understandably, these methods, although the most accurate available, are not really suited for optimized high-volume industrial processes. They don’t represent the raw material flow since they are sample-based, destructive and take a lot of time and resources to perform.

Together with SLU (Swedish University of Agricultural Sciences) and the Swedish Energy Agency we have investigated qDXA (Quantitative Dual-Energy X-ray Absorption) as a real-time method to measure moisture, ash and energy content levels in bark and branches and tops.

Measuring energy content. How cool is that?

The results so far have been very encouraging. In the lab we have seen accuracy levels on par with or better than the levels which are currently accepted by the industry. It’s still early days but as we continue to improve the measuring methods and algorithms we expect to reach even higher levels of accuracy for these complex materials.

Our current plan is to implement qDXA technology in pilot Flow Scanners for the bioenergy industry during 2015. These scanners would enable real-time bio energy incinerator optimization irrespective of biomass composition.

Note: The EES program (which focuses on efficient forest fuel supply systems) is funded by the industry and managed by Swedish research organisation Skogforsk.