Gas turbine ship
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A gas turbine ship ( international prefix : GTS , from English: gas turbine ship ) is a special case of the turbine ship , namely a ship whose main propulsion is formed by one or more gas turbines .
technology
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Advantages and disadvantages compared to other types of drive
Gas turbines are valued as ship propulsion primarily because of their high power density (ratio of power to space requirement and weight). They are therefore mainly used where high performance is required in the smallest of spaces, where high speeds are driven and where the relatively high investment costs of the gas turbine are less important, for example in the military sector. For more spacious ships and in civil seafaring, a cheaper diesel engine is usually preferred for economic reasons .
In the cramped engine rooms of high-performance ships, the high power density represents a significant advantage over large-volume diesel engines or even steam boilers with steam turbines. Accordingly, most ship gas turbines are aero derivatives derived from particularly compact and powerful aircraft engines .
The gas turbine can develop its strengths above all at a high speed that is as constant as possible, i.e. when driving for a long time and at top speed. In part load and in the lower speed / speed range, other forms of drive, especially diesel engines, are more flexible and economical.
A disadvantage compared to diesel engines or steam power drives is that the high-performance turbines used in aviation place significantly higher demands on fuel quality. They cannot easily be fired with the usual marine diesel fuel or even with cheap heavy fuel oil ("bunker oil").
Another problem for the sensitive gas turbines is the salty, humid sea air, which can lead to corrosion and deposits in the turbine. Internal combustion engines are less susceptible here.
As a drive for submarines , gas turbines are fundamentally not useful because of their properties . When submerged, the GT cannot be used because of its enormous air requirement and the advantages of high performance and speed in submarines hardly play a role on the water surface. Experiments such as the Walter turbine operated with hydrogen peroxide as a submarine or torpedo drive have not proven themselves.
Drive concepts
Since the strengths of the gas turbine only come into their own in the upper speed range, a GT is rarely used as the only drive unit. Usually a GT for top speed is combined with one or more other drives for slow travel and for maneuvering. This is usually a diesel engine (" CODAG " / " CODOG " / " CODLAG "), more rarely a smaller gas turbine (" COGAG " / " COGOG ") or a steam turbine (" COSAG " / " COGAS ").
In the case of the combination with a steam turbine, this can either be supplied with steam by a separate steam generator or use the energy from the exhaust gas of the gas turbine via a waste heat boiler (working principle as in a combined cycle power plant ).
If a gas turbine is used as a direct drive, it can be combined with a water jet drive , as this is most effective at high speeds and speeds - especially where the gas turbine has its strengths.
Often the GT is not used as a direct drive, but as a turbo-electric drive , i. H. via the intermediate stage of electrical energy. This has the advantage that the drive machine and drive can be spatially separated; the very compact electric motors for propeller drive can even be integrated into a propeller nacelle , often referred to as a pod in marine technology.
history
Attempts by Holzwarth
The gas turbine was tested in practice from 1911 onwards, but did not establish itself as an aircraft engine until fifty years later. Hermann Föttinger had already pointed out in 1909 for its use as a ship propulsion system. In 1912, Hans Holzwarth reported to the Shipbuilding Society of gas turbines on the basis of his own experiments and gave examples of their future use in shipping.
The Holzwarth gas turbine was an "explosion" turbine with which he carried out his first experiments with gas as a fuel from 1905. In contrast to the gas turbines customary today, no compressor was required to build up pressure; the pressure build-up was achieved by ignitions in several combustion chambers arranged in a ring, which can be closed by valves. The test machine, which Holzwarth calls the first turbine, was developed by Gebr. Körting A.-G. Hanover built. According to Holzwarth, the first operating turbine was also built by Brown, Boveri & Co., Mannheim-Baden. The gas system was supplied by Jul. Pintsch A.-G., Berlin and the ignition systems by Robert Bosch, Stuttgart.
Holzwarth used a 2-stage Curtis turbine with a dynamo to reduce the pressure and generate useful energy of the planned 1,000 hp . He saw the elimination of the steam boiler and condenser as an advantage. Compared to a 1,000 HP gas piston engine that was common at the time, its vertically arranged gas turbine required only 20% of the weight. Holzwarth saw further advantages in the vibration-free running of the gas turbine, no cylinder oil was required and no washing of the turbine blades by water droplets in the steam.
A test machine built with Körting ran successfully in 1909 and a Föttinger gearbox was proposed for the propeller drive. However, the practical efficiency of 12-15% was much lower than expected. The diesel engines were still in the pioneering phase at that time, but had an efficiency of around 25% before 1900.
Military ships
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The first ship with gas turbine propulsion was the MGB 2009 , a motor gun boat of the British Royal Navy in 1947. The British aircraft engine manufacturer Metropolitan-Vickers (Metrovick) received the order to develop the propulsion system and to be equipped for it Jet engine type F2 / 3 with a power turbine for the screw drive. After the tests were successful, the drive was used on patrol speedboats of the Royal Navy; the first gas turbine ships designed as such.
The first larger warships to be equipped with gas turbine propulsion were the Royal Navy's Tribal-class frigates , which contained a Metrovick GT in a COSAG configuration. The first ship of this class, the HMS Ashanti , entered service in 1961.
Almost at the same time, the German Federal Navy also used a GT drive for the first time on the frigates of the Cologne class (F120). Two GTs from Brown, Boveri & Cie. in combination with two diesel engines each. This was the world's first implemented CODAG drive.
From the late 1960s, the naval forces of many nations followed suit and introduced gas turbine propulsion, for example:
- the German Navy with the speedboats arrow and beam, Vosper class (1963-1965)
- the Swedish Navy with the torpedo boats of the Spica class (from 1966) and converted warships of the Norrköping class
- the Finnish Navy with the corvettes of the Turunmaa class (from 1968)
- the Canadian naval forces with the destroyers of the Iroquois class (from 1972)
- the US Coast Guard with the high-performance cutters of the Hamilton class (from 1967)
- the US Navy with destroyers of the Spruance and Kidd class (from 1972) and frigates of the Oliver Hazard Perry class (from 1977)
Today gas turbines are used as propulsion systems in numerous warships from many nations, from small speedboats to huge aircraft carriers (for example the British Invincible class from 1980 or the modern Queen Elizabeth class from 2014) and amphibious assault ships (for example the Wasp -Class from 1998).
Civil ships
The first attempt at civilian use of gas turbines in shipping was on the oil tanker Auris from Anglo Saxon Petroleum (a subsidiary of Royal Dutch Shell ). One of the four main engines of the Auris was initially replaced by a 920 kW gas turbine for testing purposes in 1951. It was an open-type gas turbine (BBC) with gas temperatures around 630 ° C, with a fuel utilization of 21%. After successful testing, the drive of the Auris was completely converted to a 4270 kW gas turbine with reduction gear in 1956, which enabled it to travel at around 13 knots. The Auris was launched in 1960 and scrapped in 1962.
After the Second World War, the United States looked for ways to modernize its Liberty freighters to make them more attractive for sale and civilian use. In 1956, the freighter John Sergeant was equipped with a GE gas turbine drive that ran on heavy fuel oil. After the attempt was successful, more Liberty freighters were converted and GE developed the GT technology further. At the same time, attempts were made to install gas expansion turbines behind a free-piston machine as a compressed gas generator , for example on the Liberty freighter William Patterson . In this drive, known as the Pescara plant, the turbine acts as an exhaust gas turbine, similar to the combination of a steam engine and an exhaust turbine. This doubled the efficiency from around 20% to 40%. The first German gas turbine ship, the Sagitta gas turbine trawler built in 1957/58 and the Fritz Heckert cruise ship built in 1959/60 also worked according to this principle . However, this drive concept did not catch on.
The first new construction of a gas turbine cargo ship was in 1967 by the US Navy chartered Adm.Wm.M. Callaghan for military sea transport . The twin-screw ship was equipped with two Pratt & Whitney FT4 aircraft turbines, each with 18,375 kW, which had been converted for on-board operation. She reached a speed of 25.5 knots and thus held the speed record for cargo ships on the Atlantic for two years.
The first company to operate gas turbine cargo ships built exclusively for regular freight traffic was the Seatrain Lines shipping company , which between 1971 and 1981 used four container ships powered by P&W gas turbines in regular trans-Atlantic cargo traffic. The first to be launched on October 24, 1970 was the GTS Euroliner at the Rheinstahl Nordseewerke shipyard in Emden . It was powered by two Pratt & Whitney FT4 A-12 gas turbines with 22,700 kW each. She reached a speed of 26.5 knots and used about 300 tons of fuel a day. It also achieved the speed record for cargo ships on the Atlantic. Under the price pressure of the oil crisis of the 1970s, attempts were made to convert gas turbine ships to cheaper fuel quality. For this purpose, "navalized aircraft gas turbines" taken over from aviation were used, which were also referred to as marine gas turbines. Heavier materials were used for the marine gas turbines and the combustion chamber was modified to burn gas and diesel oil instead of kerosene. Since these attempts did not produce satisfactory results, the ships were converted to diesel engines in 1982.
In 1973 the Australian company Broken Hill Proprietary Company built two RoRo ships for the rapid transport of iron ore. These were the first ships with heavy-duty gas turbines.
Probably the most famous gas turbine ship in history is the Finnjet . When it entered service in 1977, it was the first GT-powered ferry (CODAG), and for a long time it was the fastest conventional ferry in the world.
Well-known gas turbine ships
Euroliner container ships
The Euroliner , built in 1971 by the North Sea Works in Emden for the English shipping company Scarsdale Shipping Co. Ltd., London, was powered by two gas turbines from Pratt & Wittney with 59,420 hp. The 1700 TEU container ships measured at 28,430 GT, also known as container jets, ran around 27 knots and thus entered the group of the fastest liner carriers. Only the six 2,000 TEU steam turbine-powered ships built for the American shipping company SeaLand were even faster at over 30 knots. However, the Euroliners were converted to diesel engines after the oil price increases in 1982.
Finnjet
In 1977, Finnjet opened a ferry route for passengers, cars and trucks between Germany (Travemünde) and Finland. It was driven by two Pratt & Wittney gas turbines with 43.7 MW (59,420 hp) each at 8,300 rpm, which acted on two variable-pitch propellers via gears. Due to the high speed of 30 knots, only one ship was enough. The reality of the second oil crisis quickly caught up with Finnjet and the fuel prices for shipping rose extremely. The gas turbines became far too expensive to run and the propulsion system received two additional diesel engines. The ship was operated with gas turbines in summer and with diesel engines (18.5 knots) in winter.
Millennium ships
From 2000 eight cruise ships with 90,000 GT with gas turbine drive were built. The shipping company Celebrity Cruises received 4 ships with 90,000 GT from the Chantiers de l'Atlantique shipyard in Saint-Nazaire (France). The Meyer shipyard in Papenburg delivered to Royal Caribbean Cruises also decreases four of these ships. The combination of gas turbines (2 × GE LM 2500), generators and 2 controllable pods (2 × mermaid pods, each 20.1 MW drive power) was chosen as the main drive.
Queen Mary II
The Queen Mary 2 with a total of 172,400 hp installed power for propulsion and hotel operation is designed as a special feature for two applications. As a cruise ship with a normal speed of 20 - 24 knots, the diesel engines (4 × Wärtsilä 16V46CR with 22,850 hp each), which drive the generators for driving and the other power supply for the auxiliary machines and the hotel, are sufficient.
A higher speed is required for the classic transatlantic voyage between Southampton and New York City. Then the two General Electric LM2500 + gas turbines, each with 40,500 HP, can supply additional drive energy to the four electric 30,000 HP drive motors with integrated propellers in pod design. This achieves a maximum speed of 30 knots.
HSS ships from Stena-Line Göteborg
For reasons of competition, short travel times are more important than high fuel costs, especially for passenger and freight ferry services over short distances. This is why fast ferries with extremely high drive power are gaining ground worldwide and creating new fields of application for gas turbines.
The two HSS ferries (HSS = High-Speed-See-Service) for 1,500 passengers and 375 cars of the Swedish Stena-Line Gothenburg, which were built by Finnyard (Finland) in 1997, were considered the largest and most powerful fast ferries. The two HSS-1500 catamarans operate between England and Ireland and are powered by four gas turbines and water jets with a total of 106,000 hp. Two smaller HSS-900 catamarans with 46,300 HP for 900 passengers and 210 cars were built in 1995 by Westamarin, Kristiansand (Norway). They sail in the Baltic Sea and connect Sweden with Denmark.
literature
- H. Holzwarth: The gas turbine. Lecture in 1912 at the STG general meeting in Berlin. In: Yearbook of the Shipbuilding Society . Springer Verlag, 1912.
- MP Boyce: Gas Turbine Handbook. Springer-Verlag, 1998, ISBN 3-540-63216-6 .
- Hansheinrich Meier-Peter, Frank Bernhardt (Ed.): Handbook ship operating technology. Seehafen-Verlag, Hamburg 2006, ISBN 3-87743-816-4 .
Individual evidence
- ^ Brian W. King: Propulsion Systems. University-National Oceanographic Laboratory System. ( www.unols.org ( Memento of May 24, 2010 in the Internet Archive ); English; PDF file; 336 kB)
- ↑ ( page no longer available , search in web archives ) Miramar (English)
- ↑ a b c Rolf Schönknecht, Uwe Laue: Ocean freighters of world shipping. Volume 1, transpress Verlag, Berlin 1987, ISBN 3-344-00182-5 .
- ↑ Hamburger Abendblatt dated February 24, 1958 (PDF file; 2.14 MB)
- ↑ ( page no longer available , search in web archives ) Miramar (English)
- ↑ ( page no longer available , search in web archives ) Miramar (English)
- ^ Shipbuilding World and Shipbuilder. Volume 203, 2002, p. 21.