Typically cobs are not handled in country elevators. The system described here is taken from Mukunda -2007) and also based on the authors ’ visit to this facility. Corn cobs are delivered by trucks from seed processors to the facility where they are weighed and blown

Elevator Cob processing Ethanol plant

(Dry mill)

Figure 7.8. Grain and bulk (cob) handling operations in an elevator and in dry-grind com ethanol plant.

pneumatically unto a pile several meters high. Trucks are weighed before being unloaded but no grading is done to the cargo. The cob pile is stored uncovered and reclaimed daily for processing at the cob mill about 400 m from the cob pile by using front bucket loaders. Cobs delivered to the processing plant are first dried with a rotary drum dryer and stored in steel silos from which they are fed into the plant and processed to various dried granular bulk products that are packaged in 50-lb bags or large 2000-lb bulk bags.

The inbound receipt of cob delivery trucks appear not to be a bottleneck at this facility, because the inventory of cobs at the facility stored in the outdoor pile is large to meet many months of production. Because the topmost layer of cobs on the pile protects the cobs beneath the pile from deterioration above the threshold quality limit for use, the outdoor storage can be used as a low management system in this operation. Outdoor storage can be applied to cobs because of their rigid solid form, which does not drastically deteriorate as a result of spoilage from inclement weather, making handling very difficult. However, spontaneous combustion and fires that smolder for days occur in the cob pile at this plant once every several years. Therefore, the management approach of outdoor storage at this plant, while low in operational cost, can be expensive if all the pile is lost in a fire. Outdoor storage might not be feasible for all biomass types and so the effect of storage on subsequent han­dling must be considered on a biomass-type basis. For example, the mechanical strength of lignocellulosic plant biomass, like wheat and rice straw or switchgrass, would degrade much faster in outdoor storage than corn cobs, and this would affect their subsequent handling and processing such as grinding and flow through material-handling equipment.