Diesel Bug the basics. An introduction to the microbial contamination of fuel

Transcription

1 Diesel Bug the basics An introduction to the microbial contamination of fuel

2 2 detecting microbial contamination in fuel Diesel Bug the basics Summary Diesel bug has been around in maritime circles for as long as most people can remember. Everyone seems to know of someone who has experienced the problem or has encountered it themselves. The problem seems to wax and wane with no particular pattern. The reason that this topic has hit the marine press headlines recently, is that its incidence is expected to rise as a result of a new red diesel specification. The new specification has been driven by EU emissions targets. This booklet aims simply and succinctly to summarise the main issues, provide guidance on current thinking and provide reference sources for further help and support. It capitalises on the body of expert opinion drawn together for the October 2010 Marine Forum.

3 DIESEL BUG THE BASICS 3 Main issues 1. Fuel specification and supply The EU Directive 2009/30/EC came into force in the UK on 14 Jan It introduced new standards for Marine Diesel Fuel to be used by Inland Waterway Vessels and Recreational Craft when Not At Sea. The change was motivated by the need to reduce greenhouse gas emissions and was triggered by EU legislation. The new fuel specification allows for lower levels of sulphur and higher levels of bio-fuel. These changes have cost, engineering and safety implications. The Dept for Transport s (DfT) consultation process with the marine industry on the implications of new fuel specification continues. Previous fuel standards The UK specification for red diesel, in force since 2008, allowed up to 1000 ppm (0.1%) sulphur content and contained no bio-diesel. Red diesel has traditionally been used in marine and Non-Road Mobile Machinery (NRMM) applications (agriculture, rail, construction plant etc). Current fuel standards The new red diesel specification, BS2869 Class A2 applies to all NRMM, which definition includes Inland Waterway Vessels and Recreational Craft, when Not At Sea. It is very similar to the specification of DERV (EN590) for use in road vehicles, which contains an increased proportion of bio-diesel (fatty acid methyl ester - FAME), currently up to 7% FAME and less than 10ppm sulphur. From 1st January 2011, the latest European Directive stipulates that the limit on sulphur content of NRMM and Inland Waterways Diesel fuel be reduced to 10 ppm (0.001 %). This fuel is known as Ultra-Low Sulphur Diesel (ULSD) or Sulphur-Free fuel. Some suppliers have achieved the requirements by taking EN590:2007 road fuel and adding the red Duty marker dye, which could therefore contain up to 7% FAME. Red diesel with reduced sulphur but with no bio-diesel content (FAME free) is currently available. FAME free does not mean that the fuel will be absolutely without FAME content. The refining, blending, production and transportation facilities for UK fuel are common to all fuels. This means that very low levels of cross-contamination between fuels will be present at parts per million levels. The fuel companies strive to keep this contamination to a minimum i.e. to achieve de minimus levels of FAME along, with other contaminants. The DfT is now involved in discussions with the maritime community, including manufacturers of marine and industrial diesel engines and representatives of the sectors involved including the British Marine Federation and the Passenger Boat Association.

4 4 detecting microbial contamination in fuel The special characteristics of marine engines and their operation are now understood by the regulators. These characteristics include: On-going requirement for the new fuel to accommodate old but reliable technology Winterisation of marine craft Proximity of marine fuel systems to water Safety considerations of operating on water Inland waterways vessels also work at sea. If market demand continues, refiners, blenders and distributors will provide options of: EN590:2007 road diesel fuel (DERV), at Duty-paid price, with less than 10 ppm sulphur and up to 7% bio-diesel, as currently available for road vehicles. The same fuel with red dye added, calling it red diesel, at Duty-free (for commercial or nonpropulsion leisure purposes and for use by Inland Waterways vessels and other vessels when Not at Sea) either under EN590:2007 or BS2869:2010 specification. If Specifically Ordered By Description : red diesel fuel, to BS EN 2869:2010 Class A2 and red dye added, for Duty purposes, with less than 10 ppm Sulphur but zero % or de minimus bio-diesel. This FAME free red diesel should become the fuel of choice, for inland waterways operators. In UK tidal port areas, where the UK regulations do not apply and where ships Marine Gas Oil is available from distributors, sea-going operators may order fuel to ISO8217:2010 Category DMA or BS2869 Class D (essentially the same fuel), which is by specification free from FAME but has sulphur at up to 1,000 ppm.

5 DIESEL BUG THE BASICS 5 2. Fuel storage and operation Characteristics of sulphur & bio-diesel The storage and management of fuel of the new specification, with lower sulphur content and a percentage of bio-diesel, requires additional precautions at all points of the supply chain as well as in operational use. The role played by these 2 components in fuel is described briefly below: Sulphur Sulphur has 2 key characteristics affecting storage and operational use. Firstly, it enhances fuel lubricity, so without it engine components tend to wear faster. Fuel consumption may also be higher due to increased friction. It also appears to have a bio-static effect, so may suppress the growth of the diesel bug. The science behind this observation is under investigation but what is clear is that the combination of lower sulphur and increased levels of FAME has enhanced the potential for bug problems. Bio-diesel (FAME) Bio-diesel may come from a variety of natural sources ranging from chip shop waste and abattoir residue to specifically grown and managed crops like jatropha and palm oil. Whatever its source, it is more hygroscopic than traditional fuels. In other words it attracts and holds water, so it is more prone to produce condensation issues in fuel systems. Extra water in the fuel system may have adverse effects on seals, flexible pipes and gaskets. It can affect the performance of the rubber and synthetic seal compounds used in pump seals and flexible fuel pipes. It also improves conditions for the growth of the diesel bug. Diesel bug Microbes take advantage of just about every food source on the planet, including fuel. They only need water and food to proliferate. Microbes include bacteria, yeasts and moulds. They tend to prefer to live at the fuel/water interface, living in the water and feeding on the fuel. They also have a tendency to hide in the lower flow areas of a fuel system where the lack of turbulence allows them to thrive in relative safety.

6 6 detecting microbial contamination in fuel Microbes in small quantities do little harm to the fuel system. It is when they become established that problems like blocked filters start to show, affecting engine efficiency and ultimately posing operating risks to crew and other waterway users. When really established, over a period of time, these microbes begin to corrode the fuel system. They can wear injectors and even produce holes in stainless steel tanks. At this advanced stage, fuel system maintenance is likely to require specialist intervention. Water Water is likely to be present in all fuel systems (storage and operational). It may exist as free water, visible as a separate layer below the fuel or as a hazy layer between the water and fuel layers. The hazy layer consists of microscopic droplets of water suspended in fuel. This is known as absorbed water. The condensation process liberating the water is precipitated by the temperature changes involved in normal operations, including the effect of prevailing weather conditions. Cleansing effect The inclusion of bio-diesel in the fuel provides a cleansing effect in mature fuel systems. The effect results in deposits inside tanks, pipework and pumps becoming detached. This detached debris will mainly be trapped in fuel filters, but micron sized particles can pass through the pump and reach the injectors. The injectors can then become corroded as a result. The DfT recommends that farmers replace equipment filters after the first 2 or 3 tank refills in case any deposits of contaminants have been dislodged. A blocked filter is considerably less costly than a fuel pump or injectors. Were either of these to fail there may be warranty issues if traces of bacterial sludge are found on inspection by the manufacturer. The preventative maintenance approach good housekeeping Good housekeeping and fuel system management are the antidotes to the diesel bug. For marine operators this includes: Filling tanks, prior to vessel lay-up over winter, to reduce the chance of condensation Draining water regularly from the bottom of the tank, including the hazy layer (diesel has a lighter Specific Gravity than water and therefore floats above it) Testing regularly for diesel bug (at least annually) Treating as appropriate to test findings including Biocide, Fuel Polishing, Fuel System re-design

7 DIESEL BUG THE BASICS 7 Testing There are 3 types of test technology, whose main pros and cons are described below: Immuno-assay Accurate on site test delivering results in 1o minutes. No special skills or equipment are required. Colony counting Results in 1-4 days. Little skill needed to conduct the test. Some capital costs and facilities are required to purchase and suitably site an incubator. Requires disinfecting before safe disposal. ATP Reads the levels of live organisms, but some free ATP and dead material may be detected.. The results are obtained within an hour. Significant capital investment is required to purchase, house and use the equipment. Remedies The chosen test will provide a reading to indicate the level, and in some cases type, of any contamination present in the fuel or storage system. The test result will guide the selection of the remediation strategy. Low Contamination Levels may be dealt with by appropriate application of a biocide followed by retesting after a short period of time, say 7 days to ensure effectiveness of application. (Has it worked?).

8 8 detecting microbial contamination in fuel Photographs courtesy of Eurotank Environmental Limited Higher Levels of Contamination may require the emptying and mechanical cleaning of the tank. Then the whole system including tank lining must be treated with biocides. In some cases tank re-lining or replacement may be required. In many cases the removed fuel may be recovered by professional filtering and polishing followed by an appropriate biocide treatment. The cost effectiveness of this treatment will depend on the volumes of fuel involved. In many applications, boats particularly, this may prove to be a difficult and expensive exercise highlighting the need for an effective tank maintenance regime alongside the regular engine servicing schedule.

9 DIESEL BUG THE BASICS 9 Sources of reference and support The UK fuel industry organisations can also provide advice and information, especiallywhere their membership needs development in this area. In the case of IBIA (below), advice is provided to both buyers as well as suppliers. The following contacts may be of assistance: Downstream Fuel Association. The Downstream Fuel Association (DFA) is a Trade Association comprising a number of companies engaged in all aspects of the fuel supply chain in the UK, from sourcing and trading to storage, blending and retailing. The DFA represents the common interests of its members by interacting and collaborating with the Government, regulators, trade associations, NGOs and standard setting bodies on matters related to the downstream oil industry in the UK and internationally when appropriate. DFA s member companies, who are variously involved with retail supply as both independent retailers and supermarkets are providing an increasingly large share of the UK market for road fuels. As an aggregate, they represent: At least 30 per cent of the UK wholesale road fuel market; Approximately 40 per cent of the UK retail market of petrol/diesel; and A similar and rapidly growing percentage of the UK biofuel market. For advice, contact: Federico Cellurale, Research and Policy Analyst. Downstream Fuel Association, Office: , Federico.cellurale@downstreamfuel.org.uk Federation of Petroleum Suppliers Limited. The Federation of Petroleum Suppliers (FPS) is the trade association for the oil distribution industry in the UK and Republic of Ireland. FPS members are responsible for almost all deliveries of oil for heating, agricultural, marine, industrial and commercial purposes, across the UK. For advice, contact: Mark Askew, Chief Executive, Federation of Petroleum Suppliers Limited, Office: , ma@fpsonline.co.uk The International Bunker Industry Association. The International Bunker Industry Association (IBIA) is the international trade association for the oil bunkering industry, which provides an international forum for bunker industry issues. As such, IBIA represents the industry in discussions and negotiations with national and international policy makers, legislators and other groups and bodies, to: Review, clarify, improve, develop and endorse where appropriate, industry methods, practices and documentation; Increase the professional understanding and competence of all who work in the industry; Provide services and facilities for members and others as the Board shall from time to time consider appropriate For advice, contact: Ian Adams, Chief Executive, International Bunker Industry Association, Mobile: , Office: , ian.adams@ibia.net

10 10 detecting microbial contamination in fuel Providers of MBC testing systems Conidia Bioscience Limited. Conidia Bioscience Limited produces and markets Fuelstat, a rapid (results in 10 minutes) fuel testing system that can be operated effectively, on site, by ship operators, engineers and surveyors. Specialist training and laboratory facilities are not required for positive results. Conidia also has a laboratory facility which can carry out in-depth MBC testing, to investigate fuel quality or operational problems and can also offer practical remedial strategies. For further details, contact: Gerry Herman, Product Manager (Marine), Conidia Bioscience Ltd, Mobile: , Office: /2, gerry@conidia.com, ECHA Microbiology Limited. ECHA Microbiology Limited produces and markets MicrobMonitor 2, an on-site fuel testing kit that can be operated effectively by ship operators, engineers and surveyors. Specialist training and laboratory facilities are not required for positive results. ECHA also has a laboratory facility which can carry out in-depth MBC testing, to investigate fuel quality or operational problems and can also offer practical remedial strategies. For further details, contact: Derek Collins, Product Manager, ECHA Microbiology Limited, Office: +44 (0) , Fax: +44 (0) , sales@echamicrobiology.co.uk Providers of tank and system cleaning solutions Operators, engineers and surveyors may know of local providers, which can satisfy environmental regulations and safe working practices for the cleaning of contaminated fuel tanks and systems and compliant disposal of contaminated fuel. However, the following companies are experienced with MBC contaminated fuel treatment and disposal: Eurotank Environmental Limited. Eurotank Limited is a specialist contractor and consultant to the petroleum industry, which can provide tank and system cleaning and other services to the marine sector, including: Bio-fuel quality management services, tank and pipeline endoscope investigations, tank and pipeline cleaning and tank and pipeline integrity testing. For assistance and further details, contact: Jack Aplin, Contracts Manager, Eurotank Environmental Limited, Office: , contracts@eurotank.eu.com Braemar Howells Limited. Braemar Howells Limited provides a comprehensive and diverse portfolio of 24/7 response, industrial and marine services, including oil tank cleaning, de-sludging and marine oil spill cleanup. In addition for larger projects, they also offer: Non man-entry tank cleaning, tank decommissioning, repair and installation; Oil sludge processing and waste management; Oil spill cleanup recovery systems; Oil and water separation; solid/liquid phase separation. For 24/7 assistance and further details, contact: The Duty Manager, Braemar Howells Limited, 24-Hour response: RESPONSE or , General Enquiries: , info@braemarhowells.com,

11 DIESEL BUG THE BASICS 11 Additional sources for advice Where additional suppliers of FAME-free fuels and providers of fuel associated systems and advice become known, these will be promulgated through the IMarEST Small Ships Group network and the SSG pages of the IMarEST website, ( October 2011 Marine Fuel Forum Presenters UK Implementation of EU Fuel Quality Directive David Wright, IMarEST, for UK Department for Transport Operating Issues: Engine Operability Alan Cartwright, Marine Engineer, Port of London Authority Engine Fuel Sealing Issues Alan Cartwright, Marine Engineer, Port of London Authority IMarEST Small Ships Group Original 5 April 2011 Passenger Boat Operators Perspective Rita Beckwith, Director, City Cruises Fuel Supply: Product Awareness and Retail Availability Hugh Tucker, UK Petroleum Industry Association Blending Issues John Dickinson, Fuel Oil Distributors Ltd Fuel Storage and Hygiene: Road Sector Experience Dr. Aubrey Burrows, Senior Fuel Manager, Tesco Stores Microbial Contamination Small Bug, Big Problem Dr. Joan Kelley, Executive Director, Global Operations, CABI UK Centre Fuel Monitoring and Treatment George Tippett, Managing Director, Conidia Bioscience Ltd Fuel and Tank Cleaning Edward Wheeler, Managing Director, Eurotank Environmental Limited Acknowledgements Conidia Bioscience would like to acknowledge the contributions from all the October 2010 Marine Fuel Forum Presenters to the content of this booklet plus the UK Major Ports Group and the following contributors: Chris Parkin Cleaner Fuels & Vehicles Department, UK Department for Transport Hugh Tucker United Kingdom Petroleum Industry Association (UKPIA) and special thanks to Eurotank Environmental Limited UK Fuel Forecourt Distributor of the FUELSTAT Marine Test.

12 Conidia Bioscience Ltd Bakeham Lane Egham Surrey TW20 9TY UK Tel: +44 (0) Fax: +44 (0) Registered in England at: 3 Acorn Business Centre, Northarbour Road, Cosham, Portsmouth, PO6 3TG. Registration Number: FUEL detecting microbial contamination in fuel Strategic Partner Marine Partner