Bursting the Iodine Vapor Bubble: Iodine Infused Aeration for Biofouling
PreventionNatasha C. Dickenson1, Kelli Hunsucker2, Jason Krumholz3,
Michael Radicone4
1Naval Undersea Warfare Center Division Newport, Rhode Island2Center for Corrosion and Biofouling Control Florida Institute of Technology
3McLaughlin Research Corporation4I2 Air Fluid Innovation, Inc.
19th International Congress of Marine Corrosion and Fouling
June 26, 2018
Biofouling and the Navy
Hull of the Ex-USS SARATOGA
• Navy vessels susceptible to high fouling pressure.• Increases drag and fuel consumption.• Overall costs (hull cleaning/coatings) for entire Navy
destroyer class ~$56 million/year (Shultz, 2011).• Hard fouling results in greatest operational costs.• Antifouling coatings remain industry standard for hull
fouling prevention.• Need for environmentally friendly methods.
Hull of the Ex-USS INDEPENDENCEHull of the Ex-USS FORRESTAL
Demonstrate the ability of iodine (I2) infusion aeration technology to reduce fouling of submerged substrates.
2014 -2015: Assess the efficacy of standard and I2 infused aeration at both temperate (Rhode Island) and sub-tropical (Florida) locations.
2016: Assess the efficacy of a scaled-up aeration system on a vessel coated with various antifoulant coatings.*
2017: Determine scalability and identify potential paths to transition the I2 infused aeration anti-fouling technology from demonstration-scale to “real world” application.
Objective
*Natasha C. Dickenson, Jason S. Krumholz, Kelli Z. Hunsucker & Michael Radicone (2017) Iodine-infused aeration for hull fouling prevention: a vessel-scale study, Biofouling, 33:10, 955-969.
• Physical barrier• push larvae away from surfaces
• Turbulence• dislodge or damage newly
settled juveniles
• Creates unfavorable environment
• super-saturated oxygen
Aeration - Mechanisms Behind Efficacy
Aeration continuous stream of bubbles directed at a surface
Iodine Vapor Infusion
Biofouling after two months
• Iodine Bubble Infusion technique uses an infusion of air to create bubbles containing low dose elemental iodine.
• I2 vapor surrounding iodinated coated resin beads used as a targeted disinfection agent for surface microbe interaction prevents macrofoulingestablishment.
• Bubbles containing I2 contact an organic surface, transfer I2 across the bubble membrane, and interfere with the microbes:
• oxidative microbiological inactivation• aerobic inactivation• disruption of organic bonds
Un-infused tube
I2 Infused tube
I2 Infused tube
Bubble Infusion Device
(I2 Air Fluid Innovation, Inc.)
Vessel Scale-Up & Coatings Evaluation• Evaluated vessel scale I2 aeration system on
inactive vessel (~8 m) in Port Canaveral, Florida.
• Sections coated to test effectiveness of I2 infused aeration as a complementary method to foul-release coatings or other biocides.
• Three coatings:• Foul-release coating (Intersleek® IS-1100)• Ablative copper coating (Interspeed® BRA-640)• Epoxy barrier coat
• Constant standard aeration with pulses of I2 for 5 minutes every 15 minutes.
• Monthly underwater monitoring (March - July 2016) to quantify biofouling accumulation.
• Ablation rate monitoring on BRA panels.
2 4 8
Vessel Scale-Up & Coatings Evaluation
Vessel Scale-Up & Coatings Evaluation
Vessel Scale-Up & Coatings Evaluation
0
10
20
30
40
50
60
70
80
90
100
Control I2 Aeration Control I2 Aeration Control I2 Aeration
Epoxy Intersleek BRA
Mea
n Pe
rcen
t Cov
er (%
)
HARD SOFT BIOFILM
CoatingHard Fouling Soft Fouling
Control I2-Aerated Control I2-Aerated
Epoxy 38% 6% 60% 71%
Intersleek 17% 2% 24% 13%
BRA 27% 4% 42% 16%
NS
Vessel Scale-Up & Coatings Evaluation
-150
-100
-50
0
50
100
% c
hang
e re
lativ
e to
con
trol
Impact of Aeration on Fouling
Total Fouling Hard Fouling Soft Fouling Biofilm
Epoxy IntersleekBRA
Negative value overall reduction in fouling type relative to the controlsPositive value control panels had less of a specific fouling type than aeration
85%96%94%
NS
70%52%
• Will aeration reduce lifespan of BRA coatings? • Increased flow/turbulence might accelerate the ablation rate of BRA coating.
• No increased ablation on any of the three stripes painted on BRA panels exposed to aeration.
• Any wear attributed to:• inconsistency in paint application • damage to the coating by barnacles
• Low flow rate of aeration system (4 l/min) not likely sufficient to increase ablation of the coating.
BRA Ablation
• Future quantitative measurements -dry film thickness (DFT)
• Longer term (> 1 year) effects of I2-infused aeration on copper coatings remain unknown.
CONTROL
I2-AERATED
2 4 8 2 4 8
Confounding Factors
NO SUN SUN
Shading
Grazing
Bubble Dispersion
Mechanical issues
• Scalability concerns related to full scale/long term deployment:• Compressor size• Delivering air to hull
• Need more information on relative cost-benefit of standard vs. I2 infused aeration
• Environmental benefits vs. environmental concerns• Viable option for niche areas or sensitive equipment where
antifoulant coatings are not an option?
• Other applications?
Scalability & Transition
• Aerated panels showed 85-96% reductions in hard fouling.
• Soft fouling reduced by ~ 50–70% when aeration was used in conjunction with Intersleek and Interspeed BRA vs. AF coatings alone.
• Benefits of I2-infused aeration:• AF coatings + I2-infused aeration alter fouling community
composition in favor of soft-fouling organisms/biofilms. • Stand-alone or complimentary method to AF coatings. • Effective both as an AF solution when coatings are not feasible (e.g. sea
chests)• Complementary technique to FR coatings which are less effective when
vessels are stationary.
• Aeration did not accelerate the ablation process which could cause paint loss.
Summary
• Regulatory acceptance of technology and understand environmental impacts of larger scale usage.
• Simulated vessel movement to improve understanding of aeration and FR coating interactions under more realistic conditions.
Future Efforts
FIT’s through-hull panel test consisting of a floating-element drag meter, a pitot-static tube, and a video camera.
Test PanelHigh Def Camera
Acknowledgments• Naval Undersea Warfare Center (NUWC) Division Newport
Investment Office• Office of Naval Research• Center for Corrosion and Biofouling Center, Florida Institute of
Technology• Michael James, Jesse Belden, and Staci O’Donnell (NUWC)