LNG BUNKERING. Europe steps up the pace

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1 INDEPENDENT INTELLIGENCE FOR THE GLOBAL BUNKER INDUSTRY Volume 10 Number 2 April/May 2013 LNG BUNKERING. Europe steps up the pace Inside: Environmental Issues Market Analysis Shipping Trends Fuel Procurement News & Events Courtesy of Port of Gothenburg

2 A growing problem Albert Leyson of Drew Marine looks at how shipowners can cut their bunker bills by tackling the microbial growth in fuel tanks Microbial growths and their effect within the marine industry are quite well known. Left to grow unabated on the ship s hull, for example, various forms of microscopic marine life will colonise and create a biofilm, which eventually paves the way for barnacles and the like, in just a matter of days. Such marine fouling negatively impacts hull efficiency and subsequently increases fuel consumption, as additional fuel would be necessary to overcome the added drag created by the now fouled hull form and skin resistance. Similarly, the fouling of fuel oil storage tanks due to microbial growth can also impact overall vessel efficiency, since specific sulphate reducing bacteria (SRB) oxidise hydrogen compounds in fuel that directly result in fuel losses. Furthermore, as the bacteria eats the fuel, it also reduces sulphate ion concentration, which comes from the sulphur content in the fuel, into hydrogen sulphide (H 2 S), thus creating a potential safety hazard in the surrounding atmosphere to personnel onboard. Due to its toxicity, flammability, and corrosivity, H 2 S has been included in the latest edition of the International Organization for Standardization s ISO 8217:2012 Marine Fuel Specification. Applicable to all fuel grades, the H 2 S parameter must not exceed 2.00 mg/kg maximum limit for both distillate and residual fuel oils, in order to possibly protect the fuel buyer and seller from this hazard. This parameter stems from further upstream, specifically in crude oil extraction, pipeline, and refinery processing, As the onslaught of microbiological attack takes hold, the conditions become more habitable for other microorganisms including aerobic bacteria, fungi and yeasts where safeguards such as the use of H 2 S scavenger type fuel additives help to mitigate the risks that this hazard poses. While the carry-over of H 2 S is possible from upstream processes, the leading cause for H 2 S presence onboard is from sulphate reducing bacteria that consume the fuel and generate H 2 S. With over 200 species of SRB known, the one most commonly found in marine fuel storage tanks has been identified as Desulfovibrio desulfuricans. While this anaerobic bacterium can survive at extreme conditions of minus 195 C to minus 100 C for several hours, when other types of animal life would simply die, it typically thrives at the oil and water interface layer with a temperature range between 30 C and 40 C at neutral ph levels. However when introduced to environments outside of these conditions, the growth would still carry on, albeit at a relatively slower rate. Nevertheless, since bacteria can double in population every 15 to 20 minutes, exponential growth rates from a single cell can lead to that rotten egg Albert Leyson is the Marketing Manager with Drew Marine USA Inc. Contact: Albert Leyson Drew Marine USA Inc. Tel: Fax: aleyson@drew-marine.com Web: Figure 1: Microbial deposit formation at the fuel oil and water interface 42 April/May 2013 bunkerspot

3 Figure 2: Pitting caused by microbially induced corrosion (MIC) odour which in turn threatens onboard crew. As the onslaught of microbiological attack takes hold, the conditions become more habitable for other microorganisms including aerobic bacteria, fungi and yeasts. The most common fungus or mould found in marine distillate fuel oils is Hormoconis resinae. As it grows and matures, this fungus creates aggregates of thread-like filaments that form coherent mats of colonies which then accumulate on fuel storage tank bottoms. Once introduced into fuel oil service systems, it is these filamentous layers of slimy fungal growth that can wreak havoc by choking and plugging of fuel filters and centrifuges as well as fouling of heat exchanger coils and fuel injection equipment. Yeasts are the third and last type of microorganisms that have been found in fuel oil systems. Yeasts such as Candida are relatively larger in size than fungi and vary in shape from spherical to elongated filaments. As both prefer a slight to moderately acidic environment in which to grow, yeasts are considered to be co-contaminants with fungi where the manifestation of yeasts produces a more suitable ph environment for fungal growth. In addition to the hazards and operational problems outlined above, microbiological The removal of water, through proper settling and effective centrifuging and filtration, is the most practical way to minimise the outbreak of microbiological contamination and containing the contamination from spreading from one part of the fuel system to another part contamination in fuel can also cause microbially induced corrosion (MIC). While MIC in shipboard systems typically occurs in low flow areas of circulating systems such as heat exchangers, static fluid areas including storage tanks and tanks under wet lay-up become effective breeding grounds for unabated microbial growth. With ships normally operating in humid marine environments, the ventilation pipes of fuel oil storage tanks allows the condensation of water on tank walls to accumulate at tank bottoms. When combined together with fuel as their food source, microbes are given the perfect opportunity to flourish and cause tank corrosion that resembles and sometimes is misdiagnosed as regular pitting. As H 2 S reacts with metallic iron to form iron sulphide (FeS), iron is removed from the tank bottom or pipe one molecule after the other. Left untreated, it has been found that MIC can penetrate steel up to 12mm within six months. All of these microbiological contamination related problems can result in increased operational and maintenance costs. They can force unscheduled outages, necessitating cleaning of filters, repair of injection equipment, or replacement of centrifuge parts as well as tank maintenance due to MIC. In addition, the fuel losses attributable to the consumption of fuel by microbial infestation can impact overall efficiency calculations in management plans. With fuel prices nearing record highs, it is important that measures are implemented to optimise the conversion of the energy stored in fuel oil into useful energy. When considering solutions in combating microbiological contamination, it is important to keep in mind that water is a prerequisite for any growth to begin. While water contamination of fuel bunkers is limited by ISO 8217:2012, it is almost impossible to prevent some moisture from condensing from within bunker tanks onboard, as well as on bunker tankers. Certainly, the ingress of water from any other sources, such as leaky steam heating coils must be remedied and prevented, if the associated problems from microbial contamination are to be effectively minimised and controlled. It is recommended to routinely sample and test various locations for water contamination to ensure that good housekeeping practices, as the crew s first line of defence, are being maintained. The removal of water, through proper settling and effective centrifuging and filtration, is the most practical way to minimise the outbreak of microbiological contamination and containing the contamination from spreading from one part of the fuel system to another part. However, in order to achieve complete control and fully mitigate the effects of microbial growth, the application of an effective fuel biocide becomes necessary. While there are many biocidal products that claim broad based applications, most are formulated for satisfactory control of water systems (e.g., cooling water). Regulatory agencies such as the US Environmental Protection Agency (EPA) stipulate the use of biocides only for specific applications, in this case, fuel preservation. Designed specifically for fuel preservation, AMERSTAT 25 offers the Figure 3: Yeast Candida Figure 4: Bacterial and fungal colonies - Desulfovibrio desulfuricans and Hormoconis resinae bunkerspot April/May

4 most cost effective solution for protecting marine fuels from microbial growth. With a density greater than nearly all marine fuel oils, AMERSTAT 25 seeks the oil and water interface to target the prime concentration of microbial growth. Fully oil soluble, it kills and achieves complete biocidal control of the entire fuel layer. Unlike some other water-based fuel preservatives that are removed from tank draining and centrifuging, AMERSTAT 25 remains with the fuel to provide lasting protection as the fuel moves from the fuel storage system into the fuel service system. Dosed at a ratio of 1:25,000 (1 litre per 25 metric tonne), AMERSTAT 25 provides ship operators with unparalleled treatment rates that offer routine and complete protection from all known types of microbial growth typically found in all grades of marine fuel oil, as well as in newer, emerging grades of biofuel and diesel blends. In order to regain As bunker prices continue to rise, the need to improve energy conversion from chemical fuel into useful mechanical energy should include the elimination of losses due to microbial growths and their consumption of the fuel control of severely fouled systems, where microbiological growths have produced hazardous levels of H 2 S, or have led to serious impairment of multiple shipboard systems, a shock dosage ratio of AMERSTAT 25 at 1:12,500 (1 litre per 12.5 metric tonne) will effectively kill the microbial offenders, and prevent further degradation and slimy sludge formation. For immediate results, fuel oil should be circulated to properly treat all affected areas of the fuel system, followed by manually cleaning or replacing individual fuel system elements, where necessary, in cases of severe infestation. In summary, as bunker prices continue to rise, the need to improve energy conversion from chemical fuel into useful mechanical energy should include the elimination of losses due to microbial growths and their consumption of the fuel. The benefits achieved from treating all fuel tanks prior to bunkering with a fuel biocide such as AMERSTAT 25 are clear. An effective treatment programme essentially mitigates all the risks associated with H 2 S formation, fuel system component fouling, and corrosion that are attributable to microbiological contamination. BUNKERSPOT INDEPENDENT INTELLIGENCE FOR THE GLOBAL BUNKER INDUSTRY Readership of over 7,000 ensures that your message makes the maximum impact Bunkerspot is a key source of quality information for all professionals working in the international bunker industry. Our aim is to provide a comprehensive, accurate and always independent view of the multi-faceted global marine fuels industry. For further information please call or info@bunkerspot.com Bunkerspot secures distribution at the key industry events each year, many of which we are the official publication, sponsor or strategic partner. Subscribers also gain full access to, which includes a subscription-based real-time news service, industry announcements and updates on conferences, exhibitions and other key events. Published by 44 April/May 2013 bunkerspot

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