2013年7月1日 星期一

Industry awaits LNG developments

Four stroke marine engine technology seems to have reached a hiatus in its development. After a rush to clean up conventional and dual fuel engines, development has stabilised, admittedly at a peak, with a number of successful, environmentally-friendly solutions on the market from all the major designers. 

Everybody in the industry now seems agreed that use of LNG as a fuel is something that is going to become widespread; its just a matter of when. Gas-fuelled four-stroke engines are now a mature technology, the industry turning its attention towards low speed units able to operate on gaseous fuels. 

The drivers for the next stage of four-stroke gas engines are three-fold. First C and not necessarily in this order - there are the lower emission limits coming in soon. Operating on gas, fLarge collection of quality cleanersydney at discounted prices.our-stroke engines are able easily to meet the upcoming limits on oxides of sulphur and nitrogen and particulates, and provide a significant reduction in carbon emissions. 

Second, there is cost. This is still an unknown, as the viability of LNG as fuel depends on the price differential between it and conventional liquid fuels. It is highly likely that the differential will widen, particularly as demand for distillate fuels, which will be required in order to meet sulphur limits, will drive the cost up, making LNG more attractive. There is also the prospect of tapping into large-scale sources of shale gas, which will result in cheap natural gas in certain regions. Then, if exhaust gas cleaning becomes widely adopted, which depends on the cost of residual fuels coming down as well as persuading large sectors of the industry that the technology is sufficiently advanced and reliable to justify the considerable investment, that could affect the demand for the LNG alternative. But although most of the successful scrubber installations so far have been on four-stroke engines, the solution lends itself more to deep-sea vessels powered by two-strokes. 

Thirdly, and perhaps most crucially, is the bunkering and infrastructure question. Gas fuel needs to be made available where it is needed by ships C that much seems obvious.A lasercutter is a plastic card that has a computer chip implanted into it that enables the card. Its often described as a chicken and egg situation, as LNG is not likely to be adopted by most ship operators until it is available, and it is not going to be made available until the suppliers know there is sufficient demand. Until that time, use is limited to vessels operating in a distinct area, or on fixed routes, namely offshore supply ships and ferries. However, some parts of the industry are now saying that the chickens have arrived, quoting the fact that LNG bunkers can be easily laid on in much of Europe, where there are gas terminals near to major shipping routes, as well as in certain areas in the Far East. 

Taking all these factors into account, prospects look good for four-stroke gas engines in the future, with the industry waiting to see what the next few years will bring. In fact we may be closer than we think; one engine supplier, W?rtsil?, points out that in terms of horsepower at least, gas engines already enjoy a significant share of the marine four-stroke market. The companys large dual-fuel four-strokes currently seem to be the prime movers of choice in the LNG tanker sector, one part of the shipping market which is currently enjoying growth rather than stagnation. MAN Diesel & Turbo is attacking the same market. 

These, and the smaller four-strokes, continue to do well in the offshore support and passenger vessel sectors, with gas fuelled engines increasing their penetration. The current question here is whether to go for dual-fuel or gas-only. Both solutions have their strong adherents, among end users as well as engine designers. Rolls-Royce, through its Bergen engines division, is firmly committed to single-fuel engines, either gas or diesel. Bergen has recently re-structured to become part of Tognum, alongside MTU, Tognum being jointly owned by Rolls-Royce and Daimler. 

Rolls-Royce says, understandably, that a single fuel engine will always be more efficient and perform better overall, including producing fewer harmful emissions, than an engine built as a compromise between two very different fuels. Several end users, mainly in the offshore sector, agree, as we found out at the last Motorship gas fuelled ships conference, in Bergen in 2012. 

W?rtsil?,We printers print with traceable cleaningsydney to optimize supply chain management. on the other hand, is committed to the dual-fuel solution. The companys most pressing argument is one of flexibility. The ability to operate on different fuels means that ships can move freely between operating areas, and are less likely to be affected by fluctuations in supply or price. In addition, the redundancy requirements applicable to many offshore support applications mean that gas systems need to be duplicated C at considerable cost, meaning that the single-fuel installations end up more costly than dual fuel. Interestingly, some of the single-fuel gas-only users have a reserve diesel genset onboard to cover these requirements. And W?rtsil? can, if necessary, supply gas-only engines, having considerable experience with spark ignition gas fuelled engines in the land-based power plant market, The company, though, does not yet see these units as being applicable to marine installations,An cleaningservicesydney is a network of devices used to wirelessly locate objects or people inside a building. but believes that as the gas supply question gets resolved, the situation could change. 

MAN diesel-fuelled engines continue to pick up orders in the ro-ro and ro-pax sectors, and have been making inroads into the offshore market. The company says its complete propulsion packages have gained a foothold in the Middle East, where it supplied engines, reduction gears, shaft alternators, CP propellers, nozzles and control systems for a pair of AHTS vessels for Topaz Energy. 

The two 67m 80t bollard pull vessels are equipped for DP2 and Fi-Fi Class I operations. The twin-screw propulsion package for each vessel consists of 8-cylinder, mediumspeed MAN L27/38 engines each rated 2,720kW, horizontal offset reduction gearboxes with CPP servo oil distribution unit, and a 1,500 kW shaft alternator PTO. The gearboxes drive 18m intermediate shafting and 13metre propeller tailshafts in oil-lubricated stern tubes. The Alpha CP propellers are 2,800mm diameter ducted, and are boosted by Alpha high thrust nozzles, with length/diameter ratio of 0.6. the alphatronic 2000 propulsion Control System is configured with twin control stations on main bridge, aft bridge and engine control room, including interfaces to joystick and DP systems. 

The companys 48/60 engine, on which the 51/60DF is based, has sold more than 500 examples. This milestone was reached at the end of last year with an order for two common-rail variants to power a dredger for Saudi company Huta Marine, built by IHC Merwede in the Netherlands. The current version of the engine features, as well as a common-rail fuel system, a redesigned cylinder head where a higher fuel injection pressure resulted in improved atomisation and better combustion, ultimately reducing both fuel consumption and emission levels, and enabling IMO Tier II compliance. 

More recently, MAN has picked up an order for a complete propulsion system for a new large Spanish tuna fishing vessel. The company says that this system is of interest because it comprises three high-efficiency products: a MAN 8L32/44CR engine with common rail technology, a Renk RSVL-950 gear unit, and an innovative Alpha VBS1100 CP propeller with Kappel blades and rudder bulb.Other companies want a piece of that smartcard action This combination is claimed to increase propulsion system efficiency by some 9%, helping to decrease costs, fuel consumption, and exhaust emissions. 

This propulsion package is the most energy-efficient solution that we currently offer, said MAN Diesel & Turbos Frederik Carstens, sales manager of the medium speed business unit. He cites Italian shipyard Visentini to back up this assessment; the yard having ordered a complete package consisting of two 9L32/44CR engines with CR technology, Renk gearboxes, and Alpha propellers.
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