(119f) Investigation of a Screening Tool for Managing the Ash Composition of Biomass Feedstocks

The development of a low-cost, sustainable feedstock supply requires the efficient utilization of a diverse range of feedstocks. Ideally, these materials will be produced and traded as commodities with the conversion plants purchasing the materials according to their specifications rather than their species. Ash content and composition are key attributes of these commodities that will impact their value for biofuels production, particularly in thermochemical systems. A significant fraction of some biomass consists of various inorganic species, commonly referred to as ash, which cannot be converted to fuel. These constituents, including Si, P, Na, Ca, K, Cl, S, and N, are also known to play a role in slagging, fouling, fluid bed agglomeration, and corrosion of plant components increasing operational costs.

Researchers at the Idaho National Laboratory are investigating a screening tool that will allow the ash composition of biomass feedstocks to be determined. This tool is based upon laser-induced breakdown spectroscopy (LIBS) that allows a rapid, elemental analysis of the inorganic content of the feedstocks. LIBS is similar, in principle, to other analytical emission spectroscopy techniques, such as inductively-coupled plasma spectroscopy, except that a highly focused laser beam instead of an electrode is used to heat and vaporize the sample. The laser offers a very compact, energy-selective, and high resolution source for this activation. Therefore, rapid and accurate measurements can be conducted on small samples with little, or no, preparation. LIBS data will be presented on various biomass material fractions along with insight on how this technique could be used to help manage ash content throughout feedstock assembly operations.