Watchdog for fuel systems
CFM-T central PLC showing real time data
According to Swiss company Aquametro, there are many reasons to monitor fuel consumption, including saving fuel, customer demand, port requirements, and predicting and scheduling maintenance.
Aquametro believes that the most important of these reasons are fuel accounting and optimising operation. The company’s experience over three years with its Contoil Fuel Monitoring – Tug (CFM-T) system bears out this observation.
The company says that tugs and offshore vessels have different operational requirements from ocean going vessels. Measures like optimised engine tuning and hull design can help fuel savings, but due to the nature of operation, the greatest benefit comes from improved and accountable cost awareness.
The key to the optimisation process is the measurement itself. CFM-T uses Contoil mechanical flow meters, with an accuracyof 0.1-0.3%. A central controller processes pulses from flow meters in the supply and return lines of up to eight engines, as well as two Pt100 temperature sensors, analogue inputs from two tank level sensors and a GPS signal.
A touch screen displays real-time consumption, speed and rpm, and can be located either in the engine room or in the wheel house. Additionally, trip and tank information, distance and noon-to-noon reporting are displayed. Optionally, a touch screen panel PC can be connected in the wheelhouse, for trending and detailed reporting. Tamper proof data and reports are transferred to local computers via LAN Ethernet or to shore via e-mail.
Swire Pacific Offshore from Singapore installed 15 CFM-T systems, equipped with an additional panel for graphic trending. Swire identified two main problems which could be tackled through fuel monitoring; namely fuel theft and fuel waste. Basically, both problems are due to the tendering and chartering character of their business. The CFM-T can be regarded as a watchdog, which compares the amounts of fuel bunkered with the amount consumed, and identifies unnecessary trips.
The GPS-assisted voyage administration records all trips and enables customer-tailored trip reports. Various operation modes (e.g. waiting, standby, working and anchor) simplify data analysis. The reports generated with CFM-T are said to offer advantages over disparate measures such as fuel dying, satellite tracking, intensive reporting or physical presence.
Aquametro says that customers appreciate the way in which accountable fuel monitoring raises awareness of fuel consumption, by showing exactly what money is burnt – and where. Further savings are achieved by analysing speed and optimising purchasing and voyage logistics. The captain can respond immediately using real-time engine and consumption data, and can be rewarded accordingly. Other measures require on-shore analysis of voyage reports. Detailed on-shore analysis can be used to schedule and optimise voyages, but may also reveal other problems, such as leakages and inefficiencies of hull, paint, propeller and engines. Long term trending and experience with fuel monitoring enables fleet managers to find out how efficiency can be improved after overhauls.
The system can quickly identify a sudden loss of efficiency, such as may be caused by a cable wrapped around the propeller or an engine problem which needs to be addressed and corrected promptly. More difficult is to determine the right time for machinery overhauls. Normal consumption is a strong indicator of good machinery condition, whereas a slow increase points at a problem which may require a closer look (rpm, SFOC) and possibly an engine inspection.
With experience, recognising such behaviour can be used to schedule engine overhauls. Extended overhaul periods give an enormous potential for additional savings. However, the company claims that even without this saving it is possible to achieve a payback time of less than one year.
Images for this article - click to enlarge
Unless otherwise stated, all images copyright © Mercator Media 2012. This does not exclude the owner's assertion of copyright over the material.
