Storage bins at a depot located 8.9 to 13.7 km from the harvested switchgrass fields. A truck receiving pit is located next to the 18.3-m diameter bins. The bins serve as large core samples of commercial-scale stacks of bulk-format switchgrass protected from precipitation with membrane technology. The picture to the right shows the erection process of the bins.
Large outdoor stacks of chopped switchgrass, protected from precipitation with membrane technology, are envisioned for commercial bulk-format storage. Equipment specific to biomass designed to continuously stack and reclaim the large stacks may reduce storage costs by being scalable to the necessary quantities of biomass needed to support a bio-economy. This is how large quantities of ore, coal, and even sawdust are handled. As a step in this direction, large bins were erected to serve as core samples of commercial stacks, and to provide an opportunity to test bulk handling and reclaim equipment. For example, a reclaim auger in each bin, similar to the one pictured for the receiving pit, was used to test the effect of overburden pressure on discharge rates. The overburden is affected by height of the stack and the associated packing of particles. It should be noted that results are applicable to biorefinery storage and handling since bulk-format biomass has preferred handling qualities and surface area for biochemical/ thermal reactions.