A VORTEX DROP STRUCTURE AS DEAERATION SYSTEM FOR A SUBMARINE OUTFALL PIPELINE

  • Rolando García

Abstract

Use of submarine outfall pipelines became more common since World Bank Group issued a new guideline for maximum emissions levels for thermal power plants in 1998 (van Dijk, 2005). The more restrictive levels for temperature increase at the receiving water, requires outfall systems to conduct the water down to greater depths to achieve the required dilution standard. However, air entrainment control into outfall pipes could be challenging, especially for discharges with high flowrates for which conventional deaeration chambers become too large. The problem could turn more difficult in coastal shelf areas at seismic zones, where the hydraulic height of the incoming flow must be effectively controlled and the design not only has to pursue hydraulic objectives but also stability requirements for these massive structures subjected to relevant seismic thrusts. A vortex drop structure was designed for the cooling water discharge system of a thermal power plant in Mejillones Bay, Chile. The structure addresses the elevation difference between the return flow pipe and the ocean outfall pipelines while adhering to the spatial restrictions at the project site. Energy dissipation as well as limitation of air entrainment into the outfall pipelines were critical design considerations. Tests where done on a 1:12.5 scale (Froude) physical model. Prototype structure is under construction. Operation is planned to start on mid-2018.

References

Brooks, N. H. & Blackmer, W. H., (1962). Last update 2012. Vortex Energy Dissipator for San Diego Outfall; Laboratory Investigations - Caltech Authors, [Online]. Available: http://resolver.caltech.edu/CaltechKHR:KH-R-5.

Hager, W. H. (1990). Vortex Drop Inlet for Supercritical Approaching Flow. Journal of Hydraulic Engineering, 116, 8, 1048-1054.

United States Department of Interior Bureau of Reclamation, (1978). Engineering Monograph No. 25, Hydraulic Design of Stilling Basins and Energy Dissipators, [Online]. Available: http://www.usbr.gov/tsc/hydlab/pubs/EM/EM25.pdf.

V.N. van Dijk, (2005). Design of a cooling water outfall system. Master's Thesis. TU Delft.

Published
2018-12-30
How to Cite
García, R. (2018). A VORTEX DROP STRUCTURE AS DEAERATION SYSTEM FOR A SUBMARINE OUTFALL PIPELINE. Coastal Engineering Proceedings, 1(36), structures.16. https://doi.org/10.9753/icce.v36.structures.16