An exhaust gas economizer usually needs cleaning every two or three months due to soot build-up. This uses up precious crew time when in port and costs money. It also adds to wear and tear on the cleaning equipment.
Wilhelmsen says its newly formulated Unitor Fuelpower Soot Remover Liquid Plus increases the cleaning and maintenance interval for an exhaust gas economizer (EGE) or boiler to between 12 and15 months.
The company says extensive year-long trials on the 76500 GRT Ro-Ro Tonsberg, with a MAN B&W 7 Cylinder L70 ME-C8 main engine, clearly showed tangible benefits of using its new treatment chemical. It says using the product has clear benefits including: keeps the EGE free of soot, increases cleaning interval to 12-15 months, prevents acid formation, prevents cold corrosion, reduces risk of soot fires, is environmental friendly by reducing emission of soot particles, reduces the challenge of dealing with the acidic wash water every 3 months and does not involve the use of heavy metal compounds such as copper nitrate.Soot build-up presents the shipowner with several challenges. One is how to dispose of dirty wash water after cleaning an EGE.
The water cannot be disposed of in port and requires additional waste management.Soot deposits reduce an EGE’s efficiency as they form an insulating barrier. A one millimetre layer of soot can reduce the efficiency of the exhaust gas boiler by up to 10%. The soot deposits can also cause overheating and fire-risk.
Wilhelmsen says that the problem of soot deposit is made worse by several factors.One is metal contaminants in the fuel causing incomplete combustion, another is EGEs use of low velocity flue gas for higher efficiency. Also, a reduction in exhaust gas temperatures in modern engines and slow steaming practises increase soot deposit formation or cold corrosion in the EGE.
Another new Unitor product has been developed to tackle the challenge of waxing in distillate fuels, which can lead to blocked fuel filters and pipelines or wax settling in fuel in tanks. ISO 8217 sets a pour point limit, the temperature at which fuel becomes solid, of -6°C for winter-grade marine gasoil but does not set a limit for the cold filter plugging point (CFPP). The company says this is where the trouble starts at temperatures as high as 15°C. Unitor’s DieselPower CFPP lowers the cold filter plugging point to as much as -25°C
Wilhelmsen says that shipowners may be caught out by bunkering distillate fuel in a warm region but end up using it in a cold climate due to a vessel’s trading pattern. The chances are then high that the fuel is does not meet winter-grade specs and could cause problems.
Innospec’s fuel treatment
Innospec has launched its latest fuel treatment product, specifically developed for residual fuel grades. The additive has been developed to deliver optimum fuel performance through handling, combustion and exhaust. The dosage rate is 1 litre to 6 tonnes.
Shell tested Octamar Complete on an engine test bed engine at their Marine & Power Innovation Centre (MPIC) in Hamburg for its ability to improve specific fuel oil consumption (SFOC), stability and emissions. According to Innospec: “Dramatic improvements in ignition and combustion, stability reserve and particulate emissions were all verified on site, whilst the engine raw data was normalised and assessed by Innospec’s statisticians using industry approved methodology. The result shows an average SFOC reduction of 1.6 % across the load range, whilst a maximum reduction of 2.2% was observed at half load.”
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