摘要: |
Orimulsion is a fuel that is a bitumen-in-water emulsion made of approximately approx. 70% natural bitumen and approx. 30% fresh water. Orimulsion is of great interest to electric power utilities because of its competitive cost and pricing structure. Previous work on Orimulsion has determined it may largely float, remain suspended, or settle depending on the spill conditions. In this study, the mechanisms at work and the relative importance of different spill conditions (e.g., salinity, temperature, energy, Orimulsion concentration, particulate load, and particulate type) are investigated by: (1) forty-seven benchtop scale (3L) experiments conducted and evaluated using design of experiment principles, and (2) five flume scale (4000L) experiments. The insight gained from these laboratory experiments is interpreted in light of the limitations inherent in laboratory spills into confined vessels (e.g., vessel wall effects and absence of dilution) in order to predict the gross behavior that might be anticipated if Orimulsion were spilled in a real world,' open water setting. The most important environmental parameters identified, probably listed in order of their descending importance, were determined to be the receiving water salinity, receiving water energy, and presence/absence of suspended mineral matter. Interactions between these parameters determine whether most bitumen will ultimately float on or near the surface, remain suspended within the water column, or settle through the water column. The gross behavior of Orimulsion under different combinations of these parameters is predicted. These predictions provide the best available guidance to contingency planners and spill responders. Appendices I through VI are included in Volume II of this report, and are available from the USCG Research and Development Center upon request. |