"Solutions for Your Offshore Oil Skimming Needs"
About the Test
During the week of 16 December, 2013, Ocean Systems LLC tested a one-third scale model of the ORS-1000 oil recovery skimming system at the OHMSETT testing facility at Leonardo, New Jersey. OHMSETT is a government owned test facility operated by the Department of the Interior's Bureau of Safety and Environmental Enforcement. The skimmer model was 13' wide (39' full scale). On each end of the skimmer, 60' of boom was used to direct oil to the skimmer. The sweep width was 60'. Note that the hose manifold attached to the skimmer at the bottom of the photo was connected to a positive displacement pump that pumped the collected oil to the measuring tanks during the test.
The following photo shows the overall test setup, with the boom and skimmer in place, the skimmer loaded and ready to begin suctioning oil from it.
Eight tests were conducted during the week at various speeds (.4, .6, .75 and .9 knots) both with and without wave action to simulate wave conditions. Four tests were conducted in calm water and four tests were conducted with waves of approximately 1.25-1.5' high (scaled). This is equivalent to 3.75' - 4.5' full-scale wave heights, about the upper end of Sea State 3. These test speeds are the equivalent of .7, 1.0, 1.3 and 1.6 knots if used with the full-scale ORS-1000. Oil was spread in front of the boom and skimmer at approximately 64 gallons per minute (equivalent to 1,000 gallons per minute full scale) and the pump for the skimmer was set at a comparable rate. (The actual average pumping rate for the oil recovery was approximately 62 gallons per minute, which scales to 969 gallons per minute full scale. The pump rate for various tests varied plus or minus 10%.) The results showed that if sufficient oil was present in front of the skimmer and in the recovery basin, very little free water was present in the recovered stream. A number of tests achieved over 90% oil in the recovered stream, i.e. less than 10% free water.
OHMSETT personnel also observed the underwater portion of the skimmer with underwater video during the tests. They reported that they did not observe any oil flowing under the skimmer or boom during any of the tests conducted, even at high speeds.
A representative video of some of the testing can be seen below. In this video, while operating in the equivalent of 4.5' full-scale wave heights (about the upper end of Sea State 3) and at 1.25 knots full-scale towing speed, the ORS-1000 recovered 100% oil at a rate of 1,040 GPM.
What We Learned
The skimmer performed to the high standard we expected. We were able to sweep the entire width of the tank with no losses underneath the skimmer or boom, and we achieved (on a model basis) our goal of 1,000 GPM recovery rate. We also achieved our goal of a high percentage of oil in the recovered stream, reaching up to 100%.
We have been able to establish the parameters for optimum operation of the system and confirmed that the percentage of oil in the recovered stream is a direct function of the depth of oil in the basin between the primary and secondary weirs. With sufficient depth of oil, recovery percentages of 90% or higher are possible.
As a result of the tests, we also have some ideas for additional refinements of the system. One of these is that total system performance may be enhanced by a control system so that the pump engages only when the basin is full or nearly full. This can most readily be accomplished by a direct measurement of the percent oil in the recovered stream. This additional feature is now designed into the full scale version of the system.