World Bunkering > News > Summer 2010 > Testing

DNVPS warn on distillate standards

DNVPS managing director, Tore Morten Wetterhusen, has warned that shipowners should be aware of the potential risks involved in switching from HFO to ultra-low sulphur distillate. According to what he described as an ‘unscientific survey’ of 65 respondents concerning the introduction of 0.1% sulphur fuel in EU ports, he said 15% of respondents reported filter choking and fuel pump seizure during fuel changeover. Despite this, one-third of respondents to the survey did not regularly test their distillate fuels.

Charlotte Rojgaard, technical adviser at DNVPS fuels, said that experiences of using MGO in large slow engines is still very limited, and that owners should be aware of potential issues, particularly with regard to viscosity.

WIth regard to low-sulphur fuel more generally, she said that making low-sulphur heavy fuel oil calls for new technologies as refineries are generally not set up for it – as a result, low-sulphur heavy fuel oil is generally the result of blending. This inevitably starts affecting other parameters, including density and flashpoint. One particular problem is that as sulphur content falls, problems with abrasives rise. Moreover, fuel contamination is an increasing trend that owners need to be aware of.

That said, she concluded, most fuel can be used, provided the operator is aware of what is in the fuel and the appropriate methods for dealing with it.

H2S regulations to change

The regulations surrounding permitted H²S content in marine fuel are changing. The working group reviewing the ISO 8217 marine fuel specification has proposed that the revised standard should specify a maximum 2.00 parts per million (ppm mg/kg) of H²S in marine bunker fuel. Testing marine fuel for H²S content is critical to protecting the health of seafarers and port workers, and in maintaining the quality of the marine environment. H²S is known to accumulate in the headspaces of storage tanks and marine fuel bunker tanks.

The key issue is to measure the potential that a fuel could have to release H²S over a period of time under conditions when that fuel is transferred, heated or agitated by the rolling action of the ship. However, existing tests, including test method IP 399, may not detect low levels of H²S or fully evaluate whether H2S might be released from the fuel during onboard storage and handling.

As a result, the IP 399 test method is currently under review and the marine fuels industry has adopted a new improved analytical process, IP 570, suitable for field analysis and compliance with the revised ISO 8217 marine fuel specifications. The improved accuracy of the IP 570 test is due to its measurement of H2S in the ‘liquid phase’ rather than in the ‘vapour phase’. The test improves laboratory testing efficiency and typically reports a more precise ppm level of H²S in minutes rather than hours.

SetaAnalytics has developed an onboard H²S analyser that it says will enable users of marine bunker fuel to meet the revised ISO 8217 fuel specification, typically reporting a more precise ppm level of H²S in minutes rather than hours. The H²S analyser is the result of support for a new testing process from a number of industry stakeholders, including bunker fuel testing specialist Lloyd’s Register FOBAS and a group of major international oil companies.

In addition to bunker fuel blends, it also has the capability to measure H²S in heating oil, gas oil, diesel, distillate marine fuel and kerosene, including aviation fuel. Sample analysis is fully automatic and results are stored to memory at the end of the test. The analyser software automatically detects leaks in the system and produces error codes and alerts if sample/test analysis is void.

Real-time bunker analysis

Danish technology company NanoNord A/S has developed an in-line automated oil analyser, which offers continuous monitoring of fuel and lubricant quality, says Nanonord’s director of sales and marketing Ultan O’Raghallaigh. In addition, the system can help avoid risks associated with the manual sampling process, unrepresentative samples, and delays in receiving results from lab analysis. The system can also be used for lubricant analysis to enhance onboard condition monitoring capability.

Parameters analysed include density, viscosity, water content, sulphur, silicon and aluminium, vanadium, sodium, potassium, calcium, and oil temperature at 12.5cSt. Additional elements analysed of relevance to lubricants include iron, chromium, nickel, copper and zinc. NanoNord will launch an exhaust gas analyser module in Q2, 2010 measuring NOx, CO² and O². The oil analyser already provides SOx and indeed calculated CO² emissions based on sulphur content and fuel mass consumed. The Lab-on-a-Ship draws samples from various points on the ship, including the bunkering line, before and after fuel oil purifiers, at the engine inlets, and before and after the system luboil.

Samples are taken through automated valves at these points and transported through 25mm diameter tubing to the analyser. The elemental analysis is done using X-Ray Fluorescence. Water content is determined using a small distillation unit while density and viscosity is measured by a coriolis meter. Each test cycle takes approximately 15 minutes.

NanoNord has worked together with Lloyds Register FOBAS in the development of the system. Value limits for parameters measured by the system have been provided by Lloyds Register FOBAS. When the system measures a parameter in excess of these limits, an alert is generated with guidance notes. A help menu advising on the cause, effect and possible solutions for such alerts has also been provided by Lloyds Register FOBAS and incorporated in the system supported by remote monitoring and consultancy support.

Measurement data from the Lab-on-a-Ship are stored on a dedicated server on board the ship. The system also links with other measurement devices on board such as fuel flow meters, torque meters, anemometer, GPS and ship’s clock. This database provides comprehensive information on ship performance. The data are also transmitted via satellite to a shore-based server. Reports on ship and fleet performance can be generated by this system and automatically emailed to clients.

The system alerts crew to important changes in the fuel characteristics such as:

• Increased catfines concentration causing rapid cylinder wear;
• Increased water which can be caused by condensation, sea water leakage (the system can differentiate between salt water and fresh water) or steam leakage, leading to sludge formation and clogging of injectors and fuel pumps;
• Changes in density and viscosity resulting from stratification of the fuel.

It also enables monitoring of purifier efficiency (monitoring before and after purifier). Purifier inefficiency has been the most commonly observed problem on Lab-on-a-Ship installations over the past year.

Monitoring at the engine inlets provides:

• A final check for dangerous catfines;
• Information on energy consumption as a basis for engine efficiency measurement;
• Sulphur content in the fuel providing data for the optimisation of cylinder oil dosage.

Continuous monitoring of both fuel and exhaust gas emissions characteristics provides crew with the capability of managing and demonstrating compliance with environmental regulations.

The system can also be used for monitoring lubricant characteristics. This can be done either by automatically sampling in-line or by inputting samples manually into the analyser. Regular and systematic monitoring of lubricants, without the delay of waiting for sample results from shore laboratories enables early corrective action, for example, in the event of water leakage which would otherwise cause oil film breakdown, or in the case of the increasing presence of wear metals preventing excessive component wear and possible failure. Lubricant analysis can also form a key part of a condition-based maintenance program.

NanoNord launched its Lab-on-a-Ship system in early 2009 on a pilot basis with a small group of early customers, and also working closely with Lloyds Register FOBAS. The system was installed on five vessels – two tankers, two bulk carriers and a passenger ferry. Customers include DFDS, J. Lauritzen, Torm and BP Shipping.

The customer experience has been positive. Ejner Boderup, president of Lauritzen Bulkers stated: “We are delighted. As a tramp operator, we can’t make advance arrangements with port suppliers. We have to bunker at many different locations.