Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 7/9/2000
Publication Date: N/A
Interpretive Summary: Alfalfa is a perennial legume, which means that it fixes its own nitrogen fertilizer from the atmosphere and only needs to be reseeded every 3-5 years. It produces more protein per acre than any other crop and is known for its good soil and water conservation characteristics. These characteristics make it a highly sustainable and desirable crop that improves yields of other crops grown in rotation with it. Utilization of alfalfa, however, has been limited to ruminant (cattle, sheep, and goats) rations by the high fiber content of the herbage. This limitation can be overcome by a process called wet-fractionation, the separation of fresh cut herbage into juice and fiber fractions, each of which can be converted to valuable products. In the past wet-fractionation has been carried out in centralized processing plants. This means that the entire herbage, containing 80% water has to be transported to the processing site and waste eliquid resulting from processing must be transported back to the field as liquid fertilizer. A set of equipment was assembled to carry out wet- fractionation in the field. Two main components were a conventional screw press and a modified hammermill. Both were powered by a 120 kw diesel generator. The system was designed to process ten tons per hour fo fresh herbage. Processing yields were considered highly satisfactory and only the resulting products required over-the-road transport. This eliminated transport of large quantities of water. Wet-fractionation of forages has the potential for doubling product value. In-field processing can significantly reduce the costs of this process.
Technical Abstract: A set of equipment was assembled to wet-fractionate transgenic soybean herbage at the field edge. The two principal pieces of processing equipment were a modified hammermill and a conventional 16-inch diameter screw press. Typical throughput of fresh herbage was 6.4 tons per hour. Juice yield was 55% of the herbage weight and contained 26% of the herbage solids. The specific energy requirement was about 10 hp-hr/ton.