Receiving Facility

Grain is unloaded by positioning the hopper-bottom trailer over a unload pit and opening the hopper to allow the grain to flow into the pit. Unload time is about 5 minutes. The grain harvest season is so short that all farmers harvest the maximum amount each day to get their crop harvested before they are slowed by late fall weather delays. Often a queue of trucks forms waiting to be unloaded, thus it is typical for the unload time to average 30 minutes or more. There is a trade-off between the additional investment for a larger unload capacity and the farmer wait time. If the grain storage company invests more in the receiving facility, they have to charge the farmer more to store the grain to recover their cost.

The receiving facility typically does not delay operations at the cotton gin. Some gins haul in all modules they have under contract before they begin the ginning season. Most gins, however, begin ginning as soon as they have an inventory of modules, perhaps 100-500 modules depending on their gin capacity (number of modules ginned per day). The module haulers run continuously to keep the gin supplied. Sometimes they cannot keep up and the gin runs out of material. When this happens, the gin shuts down until the “at-gin” inventory is built back up.

The cotton gin is a mechanical process; it can be started and stopped with the throw of a switch. (This is a little bit of a simplification, but it can be stopped and restarted with less cost penalty than a sugar mill or bioenergy plant.) Gin owners want to gin the maximum number of bales per year, thus their goal is continuous operation.

Module haulers unload onto the ground in the storage yard, thus there is no waiting in a queue unless two trucks arrive at the scale at the same time. Even then, the delay is minimal. Operations at the gin receiving facility set the standard for all other biomass hauling opera­tions. The key disadvantage of the gin system is that the truck only hauls one module, thus the load is only about 6 dry t.

The sugarcane receiving facility, because of the large number of trucks unloaded per day (typically about 1000 loads per day at one sugar mill in South Florida), is an excellent example of an optimized receiving facility operation. If the unloading station is clear (no truck unloading) when a truck arrives, it side-dumps the bins and immediately returns to the field. The typical time to weigh in, unload, and weigh out is about 3 minutes. If the truck proceeds to the storage area where the full bins are removed and empty bins are placed on the truck, this operation typically takes 3-4 additional minutes.