Advanced Preprocessing Systems for Conversion-Ready Feedstocks

The heterogeneous nature of biological feedstocks leads to unreliable and inefficient conversion to final products. Advanced preprocessing, fractionation, and supply systems can mitigate variability.

With concerns of global warming and energy security becoming more prevalent in our everyday lives, additional emphasis is being placed on near-term solutions to the energy crisis. Using biomass as a source of energy is not a new approach, although new technologies are being developed to make its conversion to energy and other products more efficient and scalable.

Biomass is a highly heterogeneous feedstock with variable properties and attributes as a consequence of genetics, harvest practices, land management, climate, topography, storage, and handling practices. This variation in properties can lead to inefficient or non-uniform conversion to fuels or products.

Biomass can be used directly to produce heat via combustion (evidenced by the growth of the wood pellet sector), or in more advanced thermal and chemical systems. In general, these transformations can be described as biochemical conversion (e.g., fermentation of sugars to alcohol fuels from grain or lignocellulosic biomass) and thermochemical conversion, which uses the application of heat and pressure to break down the biomass structure to a crude, biologically derived “oil” that can be further processed to a range of traditional fuels, chemicals, and products. How these conversion processes proceed and their efficacy on a large scale ultimately depends strongly on the qualities of the biomass with respect to its intended use case.

This article explores strategies to understand biomass feedstock variability and the management of that variability through fractionation and preprocessing strategies. Here, fractionation is a key concept that refers to the mechanical separation of a feedstock to distinct subcomponents with differential properties.

At the root of this variability is the difference between sources of feedstocks (e.g., herbaceous vs. woody, monocot vs. dicot, deciduous vs. coniferous, etc.). Even a single feedstock can contain a wide range of materials with diverse properties. For example, woody feedstocks can contain whitewood, heartwood, needles, bark, and roots. Herbaceous feedstocks, such as corn stover, can contain leaves, stalks, nodes, cobs, sheaths, shanks, and husks. Each of these anatomical fractions can have both physical and chemical differences.

This article discusses the modern technologies that can be used to separate a crude low-value feedstock into distinct, higher-value fractions, and how these separations and treatments can impact low-temperature and high-temperature conversion platforms...