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Feedstock logistics encompasses all of the unit operations necessary to harvest the biomass and move it from the field or forest through to the throat of the conversion reactor at the biorefinery, while also ensuring that the delivered feedstock meets the specifications of the biorefinery conversion process. Multidisciplinary teams are designing and developing advanced equipment and systems to reduce cost, improve biomass quality, and increase productivity throughout the biomass logistics chain. Meeting the future volume targets for advanced biofuels will require innovative, high-volume supply systems, and equipment. To develop the necessary logistics systems, the Bioenergy Technologies Office is cost sharing the design, fabrication, and demonstration of purpose-designed equipment to address key feedstock challenges, including costs associated with each unit operation, moisture content, bulk and energy density, particle size and distribution, as well as other quality concerns. These logistics systems are developed through an iterative process between field research, lab research, and analysis efforts.
Bioenergy Technologies Office work in feedstock logistics is conducted in partnership with the Idaho National Laboratory, Oak Ridge National Laboratory, and a variety of industrial and academic partners, and focuses on four main areas of research and development (R&D):
The overall objective of the Technology Area's Harvest and Collection R&D is to develop cost-effective, sustainable harvest, collection, and delivery technologies and practices for a variety of feedstock types, as well as predictive models capable of identifying the impacts of agronomic and agribusiness practices on feedstock sustainability. Specific objectives of harvest and collection efforts are to identify and address barriers associated with existing harvest and collection systems; engineer advanced harvesting systems; identify the factors that impact sustainability; develop tools to help understand and predict the potential consequences associated with conflicting demands for biomass that may affect food and fuel availability in the United States; and identify actions to reduce potential impacts.
The main objective of the Technology Area's Preprocessing R&D is to reduce the cost of biomass feedstock preprocessing by increasing the efficiency and capacity of preprocessing equipment, and by developing new equipment. Specific research objectives target key performance parameters that lead to efficiency and capacity improvements. These include determining the performance parameters of existing equipment when processing various biomass feedstocks; understanding the characteristics of biomass at various stages of the feedstock logistics chain; identifying opportunities to upgrade biomass feedstock quality characteristics in various preprocessing operations; analyzing data collected from existing systems, and applying acquired new knowledge when designing new systems. Examples of specific preprocessing research goals are to identify strategies to efficiently increase feedstock bulk density and energy density and to efficiently reduce biomass moisture content to ensure stability during periods of storage.
Process Demonstration Unit
The Bioenergy Technologies Office's Feedstock Process Demonstration Unit (PDU), which is housed and operated by Idaho National Laboratory, is an integrated, mobile preprocessing research system for demonstrating production of advanced biomass feedstocks at a pilot-scale. Depending on the configuration being employed, the PDU has a throughput capacity of 5–15 tons/hour. Feedstock PDU capabilities include grinding and milling, drying and other thermal treatments, fractionation of plant components, formulation of feedstock blends from multiple biomass types, and feedstock densification. The PDU can accommodate both woody and herbaceous feedstock materials.
The technology area of storage and queuing R&D is focused on maintaining biomass feedstock quantity and quality during storage, and potentially upgrading the quality. Many herbaceous feedstocks, for example corn stover, are only harvested over a few weeks during the year in the U.S. Corn Belt. To maintain a continuous supply of this feedstock to biorefineries, storage is required. Efforts in this area focus on minimizing biomass losses as a result of biological degradation, which not only reduce the amount of biomass available for bioenergy production, but can also impact the conversion yield by altering biomass chemical composition.
Although there are many biomass formats possible (e.g., chips, bales, etc.), raw biomass often has characteristics that make handling and transportation inefficient. Unprocessed biomass leaving the field or forest is bulky, aerobically unstable, and has poor flowability and handling characteristics. Equipment exists to move a variety of biomass formats. However it can be an expensive effort to do so, especially as transport distance increases. The specific objectives of handling and transportation efforts are to determine how the biomass physical properties, feedstock type, and environmental conditions influence the deformation and flow of plant material during storage and conveyance operations; investigate compaction methods to improve biomass bulk densities that lead to improved full-scale equipment within the feedstock assembly system; identify opportunities to decrease the net cost of compaction operations; quantify biomass losses with current transport and handling methods; and to assess large scale systems in other industrial operations to determine if there are better alternatives for handling and transporting biomass feedstocks.