World Bunkering > News > Industry News > DNVPS launches catalyst fine checking service

DNVPS has launched a new service, its Catalyst Fine Particle Size Distribution Screening and Fuel System Check, at the SMM 2010 shipping technology exhibition in Hamburg.

According to DNVPs the service offers new insights into increased machinery wear experienced by ships and power plants, despite acceptable catalyst fine levels in post-purification fuel. The company expects the incidence of fines to increase as more low sulphur is burnt. Used in combination, the DNVPS Catalyst Fine Particle Size Distribution Screening and Fuel System Check provide a particle-size-and-quantity profile of catalyst fines in the fuel – before and after the separators. The resulting data paints a more accurate picture of the efficiency at which the fuel treatment plant is operating onboard the ship or at the power plant.

Explaining why it has set up the new service DNVPS says: “Composed of highly abrasive Aluminium and Silicon Oxides (Al+Si) and almost as hard as diamonds, catalyst fines are largely spherical particles originating from the catalytic cracking units in refineries. On entering the engine with the fuel, catalyst fine particles can quickly wear down piston rings, ring grooves, liners and fuel pumps if they exceed 5 microns in size and are present in sufficient quantities. Engine experts say particles in the 10-25 micron range are especially harmful to machinery components.”

It adds that, up to now, commercial fuel system check services in the market have been focusing on the quantities of catalyst fines remaining in the fuel after onboard purification. This is usually done by analysing and comparing fuel samples taken before and after the separators in order to assess the overall efficiency levels of the fuel treatment plant.

While major engine makers commonly recommend a post-treatment catalyst fine content of no more than 15 ppm, DNVPS says that there have been incidents where ships and power plants experienced anomalous component wear despite meeting this limit.

Such cases are one of the factors prompting the International Council on Combustion Engines (CIMAC) to consider a shift from focusing on fuel quality ‘as delivered’ to the ship or power plant, to fuel quality ‘at the engine inlet’.

DNVPS managing director Tore Morten Wetterhus says demand for low sulphur fuel is steadily rising, and this could in turn cause catalyst fine contents in blended products to go up. He says: “Residual fuels and particularly low sulphur products are made by blending residues with cutter stocks like cycle oil slurry, which may contain large quantities of catalyst fines. If the fuel treatment plant is not operating at an efficiency required to reduce the catalyst fines to safe levels before the fuel is consumed, the risk of increased engine wear and damage is very real.”

Describing how the damage may be inflicted, Mr Wetterhus says catalyst fine particles in the fuel may be forced into the running surfaces of cylinder liners and piston rings. These particles act like sandpaper on contact with the surfaces, escalating wear rates and hence shortening the time between overhaul. In severe cases, the resulting engine damages could compromise the safety of crew, cargo and carrier, Mr Wetterhus warns.