Optimization of Oleophilic Skimmer Recovery Surfaces

1. Background- Previous Work Optimization of Oleophilic Skimmer Recovery Surfaces Victoria Broje and Arturo A. Keller School of Environmental Science and Management University of California Santa Barbara MMS ROTEC meeting, September 2006

2. Surface textures 10 m 10 m 10 m Neoprene Steel LD polyethylene Effect of surface pattern on the recovery efficiency

3. Surface pattern U.S. Provisional Patent Application (serial no. 60/673,043) by UCSB.

4. Surface patterns

5. Oil type (Diesel, Endicott – Alaskan crude oil, and HydroCal 300 lubricant oil); • Oil film thickness (10 mm, 25 mm and 50 mm); • Drum rotation speed (30, 40 and 70 rpm); • Air temperature (10-15ºC and 25-30ºC); • Material of the recovery surface (Aluminum, Polyethylene, • Polypropylene, Neoprene, Hypalon); • Pattern of the recovery surface (smooth or grooved). Test variables

6. Surface patterns

7. Oil properties

8. Smooth drum Grooved drum Test results 30 rpm 40 rpm 65 rpm 65 rpm

9. Effect of materials and surface patterns

10. Preliminary Results from Cold Climate Research on Oil Spills in Ice Arturo A. Keller & Kristin Clark School of Environmental Science & Management, UCSB

11. Project Objectives • Understand the effect of: • Cold temperatures on recovery of viscous oils by smooth and grooved skimmer drums • Mixture of slush ice and oil on the recovery process • Material and roughness of recovery unit on oil withdrawal and slip condition • Drum rotation speed on the adhesion process, amount of recovered oil and recovered free water

12. Project Phases • Phase 1 (funded by OSRI) • Lab Scale studies • Physicochemical properties of oils at and below freezing • Physicochemical properties of oil/ice mixtures • Oil recovery by various materials for oil/ice mixtures • Evaluation of different recovery geometries (groove angle/depth) to increase oil recovery in the presence of ice

13. Test setup

14. Project Phases • Phase 2 (funded by MMS) • Field Scale studies • Tests will be conducted at end of Feb at the Cold Regions Research and Engineering Laboratory (NH) • Evaluate Endicott, HydroCal and diesel recovery at freezing temperatures, with and without slush ice • 6 skimmer drums (4 materials, 3 geometries) • Evaluation of drum rotational speed on overall recovery

15. Preliminary Results • Overall behavior • Density decreases as ice % (by weight) increases • Surface tension and viscosity behavior is strongly dependent on oil type • Higher viscosity at cold temperatures increases adhesion, but some mixtures practically don’t flow

16. Preliminary Results 60% Ice in Hydro Cal Mixture Ice and Endicott Mixture 20% 40% 60%

17. Preliminary Results • Elastomeric materials perform very well for oil recovery • Surface material is important for oil only • As ice % increases, surface material is less important • Wider grooves better for very viscous oils • Narrower grooves will be evaluated for light petroleum products (e.g. diesel)

18. Links to publications of previous work • V. Broje and A. A. Keller. 2006. Improved Mechanical Oil Spill 1 Recovery Using an Optimized Geometry for the Skimmer Surface. Environ. Sci. Tech. 40(23):7914-7918 • http://www2.bren.ucsb.edu/~keller/papers/Abstract68.pdfV. Broje and A. A. Keller. 2007. Interfacial interactions between hydrocarbon liquids and solid surfaces used in mechanical oil spill recovery. J. Colloid & Interface Science, 305:286–292, doi:10.1016/j.jcis.2006.09.078 http://www2.bren.ucsb.edu/~keller/papers/Abstract69.pdf

19. Advanced Oil Spill Recovery in Marine Environments Victoria Broje and Arturo A. Keller Bren School of Environmental Science and Management, University of California, Santa Barbara Introduction Research Method Almost 14,000 oil spills are reported each year in the United States alone. Immediate response to the release using efficient recovery techniques can significantly reduce environmental impacts and decrease the cost of the clean up. A Dynamic Contact Angle Analyzer was used for evaluation of candidate materials and selection of materials that can be most efficiently used for oil spill cleanup. Contact Angle () is an angle formed between an oil film and test surface. The difference between advancing and receeding contact angles is called the contact angle hysteresis. Contact angles can be estimated by measuring the force acting on the test surface while it is advancing and receeding through oil. Existing mechanical recovery equipment: • Shapes of the recovery unit: mop, belt, brush, disc, and drum. • Materials of the recovery surface: steel, aluminum, and general-use plastics (polyethylene and polypropylene) • Material selection has not been based on the adhesive properties, but rather on historical practice, price and availability. Force acting on test surface = weight of the plate – buoyancy force + surface tension. Preliminary Results Results of the experiments curried out with various fresh and evaporated oils and oleophilic plastics Results of the experiments carried out with Point Mac crude oil, plastics and elastomers The proposed research will help identifying parameters having major effect on oil adhesion to the recovery surface and select materials that have the highest oil recovery rate. Preliminary Conclusions • The contact angle hysteresis was found to be proportional to the ability of a material to recover oil. • Several materials have been identified as having high oil recovery potential under dry or water wet conditions. • Oil composition and surface roughness of test material was found to have a significant effect on the results of the adhesion tests. Higher roughness results in lower contact angle and larger recovered mass, for the same oil-polymer pair. Effect of material roughness on oil adhesion 0.2 mm Acknowledgements This research has been funded by the University of California Toxic Substances Research & Teaching Program and the US Department of the Interior (Mineral Management Service).