by Doug Woodyard
››› viability of making a massive technical investment • ship stability reserves, taking into account the weight of the scrubber units and how high up the funnel they would be fitted • deadweight reserves and the resulting impact on cargo capacity
• many ferries have very limited void in the ideal funnel casing location and would therefore need a special scrubber casing that would reduce cargo capacity • whether or not selective catalytic reduction (SCR) technology was already fitted to reduce NOx emissions: if so, retrofitting wet exhaust scrubbers
would be more challenging as these cool gases to below 100oC compared with the temperatures above 400oC required by SCR systems. The detailed results of the study have been offered to the European Maritime Safety Agency for independent audit and made available to relevant authorities.
Additive development combats fuel challenges A number of challenges are faced by ship
operators, not least from tighter and more widespread SOx, NOx and particulate matter emissions regulations, future carbon dioxide emission controls, fuel quality deterioration and rising overall operating costs. At the same time, shipowners remain keen to improve profitability, keep tonnage at sea for longer and comply with environmental legislation. With bunkers accounting for 40-60 per cent of ship operating costs, owners are pursuing various solutions to curb fuel costs. Some have adopted slow steaming (which is not the optimum way of running large engines) while others are opting to source the cheapest, low quality fuels (which can introduce operating problems and raise maintenance costs). Increasing demand for distillate fuels has caused refineries to rebalance their production to extract more high-end products, which leaves a greater concentration of impurities in the residual fuel: ultimately leading to a decline in bunker fuel quality. This declining quality, lower fuel sulphur content and sub-optimal engine operation affects marine engines in a number of ways: Poor fuel ignition and combustion characteristics: black exhaust smoke; injector nozzle deposits; engine component wear; poor fuel atomisation Increased deposits in exhaust tracts, boilers and heat
exchangers: risk of exhaust tract fires; reduced operational efficiency of exhaust components. Fuel instability: filter blocking; centrifuge overload; increased sludge. Fuel desulphurisation: injector plunger seizure; cylinder liner lacquering and bore polishing; increased oil consumption; fuel pump component failure. Increased catalyst fines: risk of engine wear and catastrophic failure; additional load on fuel treatment plant. Slow steaming: higher soot production; increased deposits; piston ring and cylinder liner wear.
Addressing some of these challenges, UK-based fuel and lube oil additive specialist Infineum has developed fuel-borne additives for use in residual and distillate fuels, which can deliver additional detergency and deposit control, improved cold temperature performance, better combustion and enhanced cleanliness and lubricity.
Cylinder liner lacquer and bore polishing can cause serious operating issues for engines, Infineum explains. Lacquer fills up the honing grooves in the liner, preventing optimised lubrication and causing bore polishing. Poor lubrication causes significant liner
wear, allowing lube oil to enter the combustion chamber and increase exhaust emissions and lubricant consumption. The excessive blow-by gases created pass into the crankcase, reducing engine power and oil life.
fuel
Combustion chamber and injector cleaning additives
offer cost and performance
benefits by reducing: • maintenance costs by keeping engine components (such as fuel injectors) clean and thus needing to be replaced less frequently • lubricant costs by preventing loss of oil consumption control • unplanned maintenance stops (by reducing bore polish, for example) • smoke and soot to ensure environmental compliance.
Infineum has also completed trials on a detergent package with a lubricity additive for use with low sulphur fuel. The results have shown evidence of reduced lube oil consumption, liner lacquer, smoke, soot and filter plugging, and an extension of fuel injector and oil filter life. As developments progress in meeting emission limits, Infineum warns, it is important to ensure that efforts made in one area of R&D do not adversely impact on another. As an example, reducing NOx by lowering combustion temperatures is likely to increase soot and visible
exhaust emissions, with severe implications for ship operators. Visible smoke may result in vessels being barred from certain waters (such as Alaska); excess soot may cause engine deposits and increase engine maintenance; soot can raise the viscosity of the lubricating oil to result in oil starvation and higher wear; and soot deposits can lead to more customer complaints and cleaning bills on passenger vessels. It
is
clearly important, says Infineum, to reduce the amount of soot produced by marine engines. Soot combustion improvers can reduce exhaust and turbocharger deposits, increasing efficiency and lowering maintenance, and thus delivering significant cost savings to operators.
Infineum’s technology for residual fuels is based on iron carboxylate, which is available ready to use in liquid form to offer reduced handling costs and fewer stability and health and safety concerns than its ferrocene counterpart. The additive is formulated to reduce piston deposits, soot in the exhaust tract, smoke and particulate matter. Shipping is navigating through a period of significant change, Infineum summarises. Ever-tightening emissions regulations are driving changes to fuels, lubricants, engine and exhaust after-treatment system designs as well as to ship operation. It is therefore more important than ever to understand the benefits that proven fuel additives can deliver in terms of cost savings, maintenance reduction and emissions compliance.
Infineum says it draws on experience in
tackling similar challenges from other transport sectors – along with close relationships with engine OEMs, ship operators, fuel and lubricant companies – to develop field-proven fuel additive packages to meet the problems affecting the marine industry.
LNG-fuelled tankers for inland and deepsea service
A further boost to LNG as a marine fuel was provided by the recent delivery in Rotterdam of Argonon, the world’s first LNG-fuelled tanker newbuilding. A milestone for Deen Shipping subsidiary Argonon Shipping BV, the 6,100 dwt
www.mpropulsion.com
chemical tanker signals a new era of cleaner shipping for European inland waterways. Lloyd’s Register helped the owners and regulators to identify the risks, meet regulatory requirements
and overcome the technical
challenges, reports Piet Mast, LR’s marine business manager for Western Europe: “This has been a great project and is a significant first. The nature of inland waterways traffic, which passes through or close to major population ›››
Marine Propulsion I February/March 2012 I 123
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