Biological Degradation of Biodiesel Causes, Effects, Monitoring i and Mitigation David Owen June 17 19 2009
This is what we are talking about And what we want to avoid
This is what we are talking about And what we want to avoid
This is what we are talking about And what we want to avoid
Agenda Introduction Causes Effects Monitoring Avoidance and Treatments
Introduction Can occur in tankage/pipelines anywhere in the supply chain Biodiesel Producers Refineries Fuel distributor storage Filling stations Can be in B100 or blends with regular diesel
Introduction Potential for contamination is higher with Biodiesel More hygroscopic Very low sulphur Straight chain structure very biodegradable More susceptible to microbiological i l growth
Causes
Causes Water Ingress Atmospheric condensation in fixed roof tanks Rain Sampling ports, breather vents, ill fitting seals on floating roof tanks Transportation Ballast water
Effects
Effects consequences of contamination Hazy Fuel Increased water Metabolic by-products stabilise water droplets Additional water produced Filter Plugging Biological debris Odour Anaerobic (SRB) produce H 2 S
Effects consequences of contamination Sludge Formation Deposits in tank bottoms Anaerobic bacteria (SRB) can thrive Microbially induced corrosion of tank bottom Reservoir for ongoing contamination Degradation of Finished Fuel Additives Can be rich in Nitrogen and Phosphorous Provide necessary nutrients Degraded and loose effect
Monitoring
Monitoring No surprises with the fuel system General public are fickle Fuel loses it s credibility
Monitoring - Types Fuel Appearance (from near bottom of tank) Discolouration Haze Particulates > Rapid and simple > Provides an alert
Monitoring - Types Full Microbiological Analysis - Counts Fuel Fuel /Water Interface Water > Appearance > Aerobic and Anaerobic(SRB) bacteria > Fungi and Yeasts > Time consuming for routine monitoring
Monitoring - Types Dip Slides Separated water > 2 to 7 days > May not detect some organisms Bacterial count: <10 4 - slight contamination Bacterial a count: 10 5 10 6 -moderate e contamination a o Bacterial count: >10 6 - heavy contamination
Monitoring - Types Adenosine Triphosphate p (ATP) Separated water Any drained water > Rapid less than 5 minutes > Detects all forms of living micro-organismsorganisms > Allows much more frequent monitoring
Monitoring - ATP Reaction outline Light striking photocathode th over a set time interval reported as Relative Light Units (RLU) ATP + 2 Lucerfin( red ) + O2 Luciferin( ox) + AMP + H O + Photon RLU <=> Light <=> ATP <=> Cells and Activity <=> Biomass
Monitoring -Frequency Problematic tanks Monthly Tankage with No History of Biological Activity Quarterly Tankage after Treatment Monthly until clear
Avoidance and Treatments
Avoidance and Treatments Housekeeping Clean tanks and pipelines Remove sludge Drain tanks of any free water Check biological activity of the water Develop a Robust Housekeeping Schedule Monitoring Inspection Maintenance
Avoidance and Treatments Ideal Tank design Integrity & seals are in good order (especially floating roof tanks) Suitable drain point that gives access to lowest part Suction point is clear of the bottom
Avoidance and Treatments Biocide - Best Practice 1. Lower the tank level to approximately 20% 2. Drain all of the water off the bottom of the tank 3. Inject Biocide into the suction of the recirculation pump or transfer pump 4. Let the treated tank sit idle for approximately 72 hours, if possible. 5. Drain off the water bottoms at a rate not to exceed 2% of the total influent to the waste water treatment facility 6. Re-test the tank for microbial levels to confirm that the biocide treatment was successful.
Avoidance and Treatments Biocide Types Fuel Soluble Water soluble Dual solubility Biocide Dose example 50 ppm for low infestation levels 75 ppm for moderate levels 100 ppm for severe levels > Dual solubility product will remain active in tankage as the tank is never fully drained
Acknowledgements Kristine Van Pee - Microbiologist GE W&PT Laboratory Haasrode Belgium > The photomicrographs h taken from one of many contaminated fuel studies.
This is what we have talked about They are destroyed happy motoring
Thank you for your time Any Questions