Development of an Oil Delivery System to Create Neutrally Buoyant Oil Plumes

Transcription

1 2014 Conference and Exhibition Development of an Oil Delivery System to Create Neutrally Buoyant Oil Plumes Bill Schmidt, Program Manager Dave DeVitis, Test Director MAR Incorporated

2 Acknowledgements U.S. Coast Guard Research &Development Center Alex Balsley Bureau of Safety and Environmental Enforcement Oil Spill Response Division Kristi McKinney

3 Outline Ohmsett Facility Overview Purpose of Creating Neutrally Buoyant Plumes Oil Delivery System Performance Objectives Variables in the Development of an Oil Delivery System Oil Delivery System Key Components Small Scale Testing Test Basin Application Plume Observations Lessons Learned

4 Ohmsett Test Facility Overview The U.S. Department of Interior s Bureau of Safety and Environmental Enforcement s (BSEE) National Oil Spill Response Research & Renewable Energy Test Facility The largest oil spill test tank in North America 203 meters (667 feet) long 20 meters (65 feet) wide 2.4 meters (8 feet) deep Open ocean salinity (35ppt) Moveable bridges with speeds up to 11 km/hr (6 knots) Computer controlled wave generator : Sine waves Harbor chop Pierson-Moskowitz spectrum waves JONSWAP spectrum waves Custom Spectra Full Scale Testing, Training, Research and Development with oil

5 Ohmsett Test Facility Overview

6 Purpose for Creating Neutrally Buoyant Plumes Assist BSEE and the USCG in the evaluation of available technologies to detect and track subsurface plumes Future possible applications Evaluation of ROV sampling Evaluation of subsurface sorbent barriers

7 Oil Delivery System Performance Objectives Create plumes with droplet sizes small enough to remain neutrally buoyant for an extended period of time Quantify droplet size distributions and concentrations Create plumes with repeatable characteristics Create neutrally buoyant oil plumes of size and distribution range to replicate an actual release scenario Target droplet sizes near 70 microns Nominal diameter for oil droplets to remain neutrally buoyant

8 Variables in the Development of an Oil Delivery System Parameters used in earlier subsea dispersion research provided orifice size and pressure baselines. Variables include: Discharge pressure Up to 150 psi Atomizing nozzle sizes.016, inch atomizing nozzle Test oils

9 Oil Delivery System Key Components Inline filter loop (recirculation mode) Backpressure regulator Electronic three way valve configuration Double diaphragm pump with pulsation dampener Discharge manifold Test oil reservoir

10 Oil Delivery System Schematic

11 Small Scale Testing Set-up Modular test tank Steel tank with polypropylene liner 4 ft. x 4 ft. x 8 ft gallon capacity Saltwater 42 inches water depth Oil delivery system LISST-100X particle size analyzer

12 Small Scale Testing Approach Create and measure plumes Seven atomizing nozzles tested Oil dispensed at predetermined pressures Use Diesel and Anadarko (with and without Corexit 9500) Measure oil droplet size distributions and concentrations over time

13 Small Scale Testing Procedure Pre-set test pressure while operating system in bypass mode Start LISST data collection Switch delivery system on for pre-determined duration Stop delivery system Stir/homogenize (mix) droplets within tank Collect LISST Data (20 minutes) End files Replenish tank with clean saltwater after each test

14 Small Scale Testing Procedure

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16 Small Scale Testing Conclusions (Given: other parameters remained constant) Higher nozzle pressures result in a narrower range of droplet size distributions Adding 5% dispersant reduced the mean particle size by more than 50% Dispensing into salt vs. fresh water effects oil droplet size distributions Lower density and viscosity oil resulted in smaller droplet size distribution

17 Test Basin Set-up Pumping system staged on main bridge to provide North and South movement Nozzles mounted to trolley for lateral positioning Nozzles depth varied by adjustable vertical slide

18 Test Basin Procedure Create oil plume using selected nozzles, pressure and oil Quantified plume in two ways: Statically within the plume Passing the LISST through the plume until concentrations diminished Recreate plumes to evaluate detection equipment

19 Test Basin Procedure

20 Plume Observations in Test Basin Smaller droplets were transported with the larger surfacing droplets; then re-submerged into the water column Concentrations rapidly diminished but provided ample time for detection equipment evaluations Multiple nozzles are required to dispense notable concentrations

21 Lessons Learned Full-scale oil in water detection equipment evaluations in a controlled environment are achievable while stationary and advancing Further investigation of nozzle pressures, types, and oils will likely yield the ability to create mean oil droplet sizes in any desired range Multiple nozzles are required to dispense notable concentrations

22 Lessons Learned Test oils require pre-filtering due to atomizing nozzle sensitivity to suspended particulate Oil droplet size distributions and concentrations are a dynamic measurement and require a standardized means of quantifying, defining and reporting

23 Ohmsett Bureau of Safety and Environmental Enforcement s (BSEE) National Oil Spill Response Research & Renewable Energy Test Facility