The Research and Development of a Cavitating Water Jet Cleaning System for Removing Marine Growth and Fouling from Offshore Platform Structures:Feasibility Evaluation.

摘要

The technical feasibility of using the cavitating water jet technique for removing marine growth and protective coatings from steel substrate material has been demonstrated under laboratory conditions in the initial phase of the program. The test results for this phase indicate that the CONCAVER technique can remove the fouling and coating from test panels that had been submerged in the Atlantic Ocean for up to 36 months. Test panels coated with epoxy vinyl were cleaned to bare metal. Cleaning rates of approximately 16 sq. ft. /hr. for removal of the fouling and coating to bare metal were obtained with this technique. The horsepower requirement corresponding to this rate of removal was approximately 22 hp. The results of the initial technical feasibility evaluation defined various design parameters such as removal rates, area covered, nozzle size, loss coefficient, operating pressure, intensity of erosion, jet velocity, and horsepower requirements. Specific nozzle designs were evaluated with the intensity of erosion established as a function of nozzle distance. A threshold intensity of erosion design chart has been characterized for barnacle removal. This chart identifies the margin of safety between the peak intensity of erosion and the threshold intensity for the steel substrate material. For the optimum operating conditions, cleaning rates were established for the removal of the marine growth and epoxy vinyl coating.