New Developments in Sensor Technology

By Keith Henderson at June 26, 2010 07:33
Filed Under:

Making possible the growth in Condition CM/CBM to improve reliability and maintenance on board ships is the development of computers connecting to compact sensors using, wired or wireless communications. The Silicon Valley-based SRI International, has developed advanced Vibration Imaging Technology (VIT). SRI recently granted Sensors Inc. a global manufacturing and distribution license to develop a diagnostic system using their VIT. The system uses a special camera and patented software enabling a computer to detect and analyze vibrations on the surface of objects in its field of view. No special lighting or physical connection to the object(s) is required. The opportunities for monitoring marine propulsion and auxiliary applications are indeed large. The system is so sensitive that images can be monitored pixel by pixel and any variation is immediately detected. Used to monitor the mechanical health of machinery with rotating parts, abnormal vibrations are immediately recognized by the system and may indicate intervention or shut down is required.
The growth in Condition Monitoring / Condition Based Maintenance (CM/CBM) to improve reliability and maintenance on board ships is well documented. Making this all possible is the development of computers connecting to compact sensors using, wired or wireless communications. Usually the sensor is physically attached to the object and often it is an accelerometer.

For some time now, the Silicon Valley-based SRI International, originally Stanford Research Institute, as one of the world's leading independent research and technology development organizations, has been developing advanced Vibration Imaging Technology (VIT). SRI recently granted Sensors Inc. a global manufacturing and distribution license to develop a diagnostic system using their VIT.

The system uses a special camera and patented software enabling a computer to detect and analyze vibrations on the surface of objects in its field of view. No special lighting or physical connection to the object(s) is required. Although initial interest is in automotive applications the opportunities for monitoring marine propulsion and auxiliary applications are indeed large.
The system is so sensitive that images can be monitored pixel by pixel and any variation is immediately detected. It can even pick up vibrations so small that would not be registered by an accelerometer. Noise is produced by vibration and long before an abnormal noise is reported the vibrations creating the noise would be detected by the vibration imaging software. Used to monitor the mechanical health of machinery with rotating parts, abnormal vibrations are immediately recognized by the system and may indicate intervention or shut down is required.
As this system becomes more widely available, being able to monitor equipment without wired connections and monitoring a whole area by camera will widen the scope of CM and bring further enhancements to its increasing popularity.

How Green is Green?

By Keith Henderson at June 25, 2010 07:20
Filed Under:

A Green Ship Event in Rotterdam hosted by the company Imtech. closed with a lively discussion following a series of “green” presentations..Although the term “Green Ship” is a fashionable term, it is very loose in meaning as it is so far undefined. When a ship is called “green” is it light green or dark green, and green in which respects? If it is only the hull color, then that is all it is but so often it is used to suggest the ship is somehow clean or non-polluting or low on emissions, exhaust or otherwise. Can you have a green ship without doing an audit of the whole life of the ship from conception through building, its life at sea and finally its end? Another important aspect is training, the ship can have several green features but if the crew doesn’t know how to use them, they won’t be used, so the greenness will fade. So in conclusion green is not an absolute state but more a relevant term. It would be better if we all started using the term “greener”, rather than green!
I attended a Green Ship Event yesterday in Rotterdam hosted by the company Imtech. There was a series of presentations followed by a tour of their facilities and closed with a lively discussion.

We hear the term “Green Ship” very often these days but although it is a fashionable term, it is very loose in meaning as it is so far undefined. When a ship is called “green” is it light green or dark green, and green in which respects? If it is only the hull color, then that is all it is but so often it is used to suggest the ship is somehow clean or non-polluting or low on emissions, exhaust or otherwise.

At the Event there were several aspects of “greenness” discussed. Green as regards the building of the ship or just in its operation? Is it also green when it comes to the end of its life and has to be scrapped or recycled? Nuclear submarines being a good example of emitting low emissions throughout their life but at the end? So can you have a green ship without doing an audit of the whole life of the ship from conception through building, its life at sea and finally its end?

Another important aspect is training, the ship can have several green features but if the crew doesn’t know how to use them, they won’t be used, so the greenness will fade. An example is the new Rainbow Warrior III, equipped with sails as well as diesel engines. The crews are schooled in sailing and the use of sails and the sails can be deployed and trimmed remotely requiring minimum involvement and physical effort of the crew. If it was otherwise there would be a reluctance to use the sails and just run on the less green diesel engines!

So in conclusion green is not an absolute state but more a relevant term. It would be better if we all started using the term “greener”, rather than green!

Engine cooling systems optimization

By Keith Henderson at June 20, 2010 13:17
Filed Under:

One of the many areas of interest as part of the Danish Greenship Project is reducing the energy consumption of the engine cooling systems. For the investigation, a MAN B&W engine in a 35,000 dwt bulk carrier is used to study both sea water and lubrication oil cooling systems. Project studies indicate that there is an unnecessarily high pressure drop and therefore flow resistance in the sea water cooling circuit resulting in wasteful energy consumption. By specifying a larger capacity heat exchanger the flow resistance would decrease permitting the use of smaller pumps with an energy saving that could be as much as 90 per cent and save 160 tons of CO2 per pump per year! Using a different type of oil pump and / or optimizing the flow through the lubricating oil recirculation system, around five per cent of energy can be saved, equivalent to more than 110 tons of CO2 per annum.
One of the many areas of interest as part of the Danish Greenship Project is the cooling system of the engine. It is one of the most energy consuming items and if the systems can be optimized would lead to beneficial savings.
For the investigation, a MAN B&W engine in a 35,000 dwt bulk carrier is used to study the main sea water cooling system and lubrication oil cooling system. These two systems consume the majority of the energy used for cooling.
The study found that it is usual practice for the sea water cooling system to be designed according to preliminary requirements stated in the ship’s building specifications but too early to include important items such as the flow resistance of the heat exchangers, filters and placement of these items.
Project studies indicate that there is an unnecessarily high pressure drop and therefore flow resistance in the sea water cooling circuit resulting in wasteful energy consumption. The conclusion is that by specifying a larger capacity heat exchanger the flow resistance would decrease permitting the use of smaller pumps resulting in an energy saving that could be as much as 90 per cent. This is approximately ten per cent of the total electrical power generated by the ship – a saving of 160 tons of CO2 per pump per year!
The lubricating oil recirculation system pumps oil from the lower tank or sump, passing through a heat exchanger to cool the oil, then via a thermostatic control valve, a back flush filter and into the engine. Using a different type of oil pump and / or optimizing the flow through the system, it is estimated that around five per cent of energy can be saved, equivalent to more than 110 tons of CO2 per annum.

Reducing particulates on older engines.

By Keith Henderson at June 16, 2010 11:20
Filed Under:

As emission requirements become stricter as the years pass, the question arises, what to do with older engines. The EPA Marine Engine Re manufacture Program introduces a law effective March 2008 to force operators of older ship engines to upgrade them to reduce emissions. The rules are rather limited, specifying that the improvement must reduce particulates (PM) by at least 25 per cent, that the engines concerned are commercial (not recreational) applications, manufactured after 1973, over 600kW, cylinder displacement under 30 liters and be a US flagged vessel. The upgrade only becomes compulsory if there is an EPA approved upgrade available and must be carried out at the next scheduled ‘re manufacturing event’ e.g. replacing cylinder liners. Changing many parts to effectively convert an old engine into a new model is usually not economic, nevertheless changing some parts can make a significant reduction in emissions. Although other ways to achieve the same end of reduced emissions are changing fuels, fuel additives or adopting an after treatment system.
As emission requirements become stricter as the years pass, the question arises, what to do with older engines. Although time will eventually retire these trusty old workhorses very many of them will be around for a long, long time. The EPA Marine Engine Re manufacture Program introduces a law effective March 2008 to force operators of older ship engines to upgrade them to reduce emissions. The rules are rather limited, specifying that the improvement must reduce particulates (PM) by at least 25 per cent, that the engines concerned are commercial (not recreational) applications, manufactured after 1973, over 600 kW, cylinder displacement under 30 litres and be a US flagged vessel. The upgrade only becomes compulsory if there is an EPA approved upgrade available and must be carried out at the next scheduled ‘remanufacturing event’ e.g. replacing cylinder liners. So far EMD is the only manufacturer producing such a kit. Caterpillar recently announced that they will be making kits available for some of their engines.

Marine engines are usually developed from one generation to another over many years giving the possibility that the components used to make an engine comply with modern and future emission regulations will often back fit older models of the same series. Changing many parts to effectively convert an old engine into a new model is usually not economic, nevertheless changing some parts can make a significant reduction in emissions. The parts change normally can be fitted within the engine and not require major reconfiguration of the engine room.

Although other ways to achieve the same end of reduced emissions are changing fuels or fuel additives or adopting an after treatment system: these solutions usually require changing fuel storage arrangements which is not always easy in an older vessel and can be very expensive.

Let’s hope that not only other manufacturers will join the program, but other countries will encourage fitting these improvement kits on older vessels and reduce the health hazard of PM discharge into the atmosphere.

MAN Two Stage Turbo charging

By Keith Henderson at June 13, 2010 16:29
Filed Under:

Lower exhaust emissions of large bore diesel engines without after treatment, can be realized by increasing the mean effective pressure. One way to achieve a higher m.e.p. is to increase the boost pressure of the turbocharger however standard turbo designs are already at or approaching the limit of their capability to go from atmospheric pressure to the desired boost pressure in one unit: the solution is therefore to use two turbo stages. Simply, it comprises a low pressure turbine feeding via an inter cooler a second high pressure turbine which in turn passes through a second inter cooler to the engine. Control of a two stage turbo system including the suppression of compressor surging.is complex and is effected with the aid of variable nozzle rings (VTA) and bypasses. MAN Diesel & Turbo have recently announced their own series of two-stage turbos called the New TCX Generation. Using a configuration with the turbos at 90 degrees to each to provides a compact solution and reduce the amount of piping.
In the relentless quest for lower exhaust emissions of large bore diesel engines without after treatment, increasing the mean effective pressure is a way of accomplishing it .

One way to achieve a higher m.e.p. is to increase the boost pressure of the turbocharger however standard turbo designs are already at or approaching the limit of their capability to go from atmospheric pressure to the desired boost pressure in one unit: the solution is therefore to use two turbo stages.

A sequential turbo charging (STP) configuration has been around for several years with the second turbo bringing additional charging when required. This arrangement also has its limitations hence the introduction of the two stage turbo concept. Simply, it comprises a low pressure turbine feeding via an inter cooler a second high pressure turbine which in turn passes through a second inter cooler to the engine. The exhaust gases powering the turbos pass first of all through the high pressure turbine then the low pressure turbine. Control of a two stage turbo system including the suppression of compressor surging.is complex and is effected with the aid of variable nozzle rings (VTA) and bypasses.

MAN Diesel & Turbo have recently announced their own series of two-stage turbos called the New TCX Generation. They are based on their established TCA/TCR series and use a novel layout to achieve a compact unit. As two inter coolers are required by the system, with one located between the chargers, an unusual configuration with the turbos at 90 degrees to each other is used. This provides a compact solution and reduces the amount of piping.

Development in batteries

By Keith Henderson at June 08, 2010 09:31
Filed Under:

At last month’s International Tug & Salvage Conference, Corvus Energy Ltd presented a paper on a new battery type – Nickel Manganese Cobalt , NMC for short, that is particularly good for propulsion applications. It uses safe chemistry that is stable and reliable. is sealed and is compact. It can deliver a high power until fully discharge, doesn't’t deteriorate if left uncharged and hardly looses its charge over time. What does this mean for the marine industry? One example was the announcement at the Conference of an all electric tug boat, so far it is only for training purposes but heralds the beginning of a new era of electric driven vessels whether pure electric drive or hybrid diesel electric.
At last month’s International Tug & Salvage Conference held in Vancouver, there was a very interesting presentation from the Canadian providers of (electrical) battery systems - Corvus Energy Ltd. For close on fifty years they have specialized in lithium ion technology to provide power solutions for a variety of applications of which marine is an important part.

Most of us are familiar with the lithium ion, actually lithium iron phosphate batteries as used in our laptops and cell phones which is a mega improvement over older battery types such as lead acid and nickel cadmium. What is so interesting is a new battery type – Nickel Manganese Cobalt , NMC for short, that is particularly good for propulsion applications. Partly developed for the auto-industry, this new battery seems to have only attributes without any disadvantages, except price of course!

Firstly NMC uses safe chemistry that is stable and reliable. It’s sealed and is compact, can deliver a high power until fully discharge, doesn't’t deteriorate if left uncharged and hardly looses its charge over time. In comparison to the lead acid battery, the NMC has an energy density 163 Wh/kg, against only 20Wh/kg for the lead acid type. The cycle life is 3,000 plus for NMC and only 200 for lead acid and the power per volume is 320 Wh/liter against only 75 WH/liter for lead acid. Last but not least the charge efficiency is 99 per cent for NMC, with only 60 per cent for lead acid,

What does this mean for the marine industry? One example was the announcement at the Conference of an all electric tug boat, so far it is only for training purposes but heralds the beginning of a new era of electric driven vessels whether pure electric drive or hybrid diesel electric.

Concerning the matter of cost, Corvus argue that, for example, in a marine propulsion application, the higher cost of NMC batteries can be paid off in a period of around two years when the saving in hydrocarbon fuel is put against the cost of electrical power supplied from an onshore power station.

Experiments to curtail CO2 emissions

By Keith Henderson at June 06, 2010 13:12
Filed Under:

Projects running with NYK Line ships under the Japanese Ministry of Land, Infrastructure, Transport and Tourism are investigating technological developments to curtail CO2 emissions from marine vessels. In the main project, two NYK ships, are equipped with an air blower to supply air to the vessel's bottom to reduce frictional resistance. Mitsubishi Heavy Industries supplied the engines and is also participating in the experiment. It was decided that, a module carrier, would be best type of vessel for this experiment. she has a wide, shallow-draft hull minimizing the energy required by the electrically blower supplying air to the vessel's bottom and should better retain the supplied air under the vessel's bottom.

Three parallel projects are currently running with NYK Line ships under the Japanese Ministry of Land, Infrastructure, Transport and Tourism initiative to investigate technological developments to curtail CO2 emissions from marine vessels. Project 1 concerns hull friction reduction, in a twin screw shallow draft vessel using air lubrication. Project 2 looks into using larger car carriers to reduce the CO2 emissions per car carried. Project 3 is using a navigation control system to improve planning to make better use of port berth windows and canal passage reservations, thereby reducing time wastage.

In Project 1, two NYK ships, the Yamatai launched in March this year and the Yamato due in November are equipped with an air blower to supply air to the vessel's bottom to reduce frictional resistance. Mitsubishi Heavy Industries supplied the engines and is also participating in the experiment.

It was decided that, a module carrier, would be best type of vessel for this experiment. Compared to other large vessels, she has a wide, shallow-draft hull that would produce relatively lower water pressure and therefore minimize the energy required by the electrically powered blower supplying air to the vessel's bottom. Furthermore the flat, wide bottom should better retain the supplied air under the vessel's bottom and reduce loss up the sides.

There are main objectives of the experiment: verifying the fuel savings using air lubrication, investigating the air bubble type and behavior under differing sea conditions, determining the relationship between volume of air supplied and its effect and determining the actual CO2 reduction.
Progress reports on Projects 2 and 3 will be released at a later date.

Tag cloud