SCIENCE LNG

DRÄGER REVIEW 115 | 1 / 201750

The future of international shipping belongs to gas engines. Gas detection technology is making the transition from heavy fuel oil to liquefied natural gas safer. It is also used in facilities that supply ships with power in ports. Soot particles, sulfur oxide, and nitrous oxide are thus virtually no longer an issue.

Text: Peter Thomas

A BRIGHT

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Ocean network: The diagram shows

shipping traffic on the oceans in 2012. Yellow lines

represent container ship routes, tanker routes

are in red, and bulk freighters are in blue

When the AIDAsol berths in Ham-burg, it switches off its engines, because since 2016 the LNG hybrid barge Hum-mel has been supplying it with power while the cruise ship is in dock. The barge belonging to the company Becker Marine Systems has two containers with up to 17 metric tons of liquefied natural gas (LNG) on board. Generators use it to produce power.

It isn’t easy supplying ocean-going lin-ers with power in ports; some of them use as much energy on the quayside as a small town. Laying permanent power lines is expensive. A hybrid barge, on the other hand, can flexibly reach any ship, regard-

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less of where it is berthed. The much larg-er powerships produced by Karpowership, a member of Turkey’s Karadeniz Energy Group, are powered by LNG or heavy fuel oil and work on the same principle. They deliver between 30 and 470 megawatts, while the Hummel is capable of providing up to 7.5 megawatts. That is sufficient for supplying even very energy-hungry ships with power. If a ship is in dock for around eight hours, it can use up to 40 megawatt-hours of power, which means that it needs a supply of five megawatts.

Farewell to heavy fuel oilUntil now, most cruise ships have left their own engines running when they are in dock somewhere in the world. They then use their generators to produce the necessary power while the passengers are strolling around the town. The kind

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SCIENCE LNG

DRÄGER REVIEW 115 | 1 / 2017

of emissions produced depends on the type of fuel used. The worst offender is heavy fuel oil – hitherto the most impor-tant energy source for international ship-ping. Its thick clouds of exhaust fumes with large amounts of nitrous oxide, sulfur oxide, soot, and particulates are a health and environmental risk. Ships with scrubbers fare better. The more expensive marine diesel used by most ships in port is cleaner than heavy fuel oil. Finally, LNG performs best of all in terms of emissions. Its environmen-tal benefits are also highlighted by Max Kommorowski, head of the LNG hybrid division at Becker Marine Systems. “Sul-fur oxide and soot particles are no lon-ger present in the exhaust fumes; nitrous oxide emissions are cut by up to 80 per-

The use of LNG as a marine fuel will increase

Panoramic port view with clean energy:

When the AIDAsol (left) berths in Hamburg, the

Hummel (foreground right) supplies it with power using

LNG. The energy is transmit-ted via power lines (above)

cent, and carbon dioxide emissions are up to 20 percent lower.” Accordingly, a growing number of shipping companies are now choosing gas-powered engines for their newly built ships. AIDA is also opting for purely LNG-driven engines for its next generation of ships, which is set to enter operation by 2020. “There may only be around 100 LNG-driven ships worldwide at present, but many are still being built – as such, the prev-alence of this technology should grow exponentially over the coming years,” says Maria Dimitrova, who oversees the “Shipbuilding” focus industry at Dräger. In addition, there are retrofit projects which involve fitting existing ships with gas engines or dual-fuel technology for switching between gas and another fuel (see interview, page 53).

Clever transitionYet what about the eco-friendly power sup-ply at the port for the large existing fleet of ships with older engine technology? This is where Becker Marine Systems comes in with the Hummel. “The idea for the LNG hybrid barge came about in 2012,” says Max Kommorowski. With AIDA as

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53DRÄGER REVIEW 115 | 1 / 2017

a partner, the company developed and built its floating power plant and com-missioned it in 2016. By the end of the 2016 season, the barge will probably have been used more than 30 times.

Manage the riskThe gas is supplied by containers on board. From its cryogenic liquefied phase, the LNG is then vaporized and combust-ed as classic natural gas by the engines. This also increases the risk, because there is a high danger of explosion in the event of a gas leak. “That is why operations on board the barge are monitored by a num-ber of sensors,” says Peter Wesselbaum, expert in stationary gas warning systems at Dräger. “Redundant open-path gas detectors are used to monitor the situa-tion along the gas pipes. In addition, mea-surements are taken by infrared sensors

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Dr. Thomas Spindler is head of the Upgrades & Retrofits division for four-stroke engines at MAN PrimeServ

Dräger PIR 7000: An infrared optical transmitter that moni-tors LNG operations on board the hybrid barge Hummel

“LNG is becoming ever more important”MAN PrimeServ, the service arm of MAN Diesel & Turbo, makes marine four-stroke diesel engines fit for liquefied natural gas with customized retrofits.

Dr. Spindler, what potential do you see over the coming years for retrofits which involve converting existing ships with conventional engines to dual-fuel technology with LNG as an alternative fuel? The potential is huge: Faced with ever stricter sulfur limits imposed on fuel, retrofits ensure that existing ship engines can continue to be used in the long term. Over the coming years, dual-fuel technology will continue to help LNG to gain acceptance as a marine fuel. With every retrofit in which we successfully make marine four-stroke diesel engines capable of running on LNG, we increase the demand for LNG. We are planning to develop dual-fuel retrofit kits for further engine types that have hitherto been unable to be converted. This applies to various applications such as cruise ships, passenger ferries, and cargo ships. Accordingly, LNG will be an option for a number of customers.What exactly is involved in a retrofit for dual-fuel operation with LNG? One good example is a project we are just completing – the world’s first conversion of a 1,000 TEU container ship owned by Wessels, which is driven by a Type 8L48/60B MAN engine. This engine is being converted to run on a dual-fuel principle with the components from a 51/60DF series engine. Then there is the complete storage, control, and measurement technology for LNG. Every retrofit is individually planned and carried out in several stages. On average, from the initial concept stage, it takes around a year to bring a project to successful completion. Has MAN acquired special expertise in the LNG sector with the purchase of the Marine Fuel Gas Supply System business from Cryo AB? MAN Diesel & Turbo has made a strategically important purchase for the future with this acquisition, because LNG is becoming ever more important for shipping. It allows us to offer our customers integral solutions from one single source in the dual-fuel segment and in the area of pure LNG systems. As such, we are taking up a leading position on the market.

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SCIENCE LNG

DRÄGER REVIEW 115 | 1 / 2017

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EMISSIONS

The amount of CO2 consumed to transport a metric ton of

freight one kilometer:

located at certain points – primarily with the Dräger PIR 7000.” The sensors are mostly positioned at potential leak points, but they also monitor the systems’ waste airflow. The gas treatment plant – the heart of the system – is monitored using both methods.

There are strict limits imposed on sul-fur dioxide, nitrous oxide, and soot parti-cle emissions from marine engines not only in ports, but also in the coastal areas of the North Sea and Baltic Sea as well as the east and west coasts of the USA. These Emission Control Areas (ECAs) were established by the International Maritime Organization (IMO). The regulations gov-erning these zones were last tightened in 2015. Much more relaxed rules are in force outside these areas, which is why many shipping companies are opting for dual-fuel technology. This allows them to

sail with gas within the ECA and heavy fuel oil outside. Much stricter regulations governing emissions are set to come into force worldwide starting in 2020. “This should make it very difficult to sail with heavy fuel oil under any circumstances,” says Dräger expert Dimitrova. LNG there-fore has real future potential.

Max Kommorowski is also certain that there is a bright outlook for liquefied nat-ural gas. He says that hybrid technology will play an important role in supplying anchored ships for the foreseeable future. Here the engineer is not just thinking about LNG hybrid barges like the Hummel, which Becker Marine Systems could build with an output of up to 14 megawatts. The company also has its sights on container ships. They are berthed at the terminal for between 24 and 48 hours while the cargo is unloaded and the next consignment is loaded. The idea is to supply them with so-called LNG PowerPacs during this time – 1.5-megawatt power plants in the form of four 40-foot containers, which are placed completely on the ship due to their com-pact dimensions. This should be possible sometime next year, with Hamburg ear-marked as the first location for the oper-ation. There ought to be enough demand for it. After all, cargo equivalent to 3.2 mil-lion 20-foot equivalent units (TEUs) are handled here by ships from all over the world every year.

PowerPacs will supply power on container ships

Ice-cold energyLiquefied natural gas (LNG) is the liquid phase of natural gas at temperatures below minus 160 degrees Celsius. LNG can be efficiently transported and stored outside distribution networks, because its volume is 600 times smaller than that of uncompressed natural gas. Even though energy has to be used to cool the LNG during transportation, the same also ap-plies to the transportation of gas in pipelines, where the pressure has to be regularly increased along the route. LNG is traditionally transported by tankers. However, new regulations are required for its use as a marine fuel. The IMO’s IGF Code (International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels) has been in force since 2015. Among other things, it prescribes the number of required gas detection transmitters. The focus here is on explosion prevention. Furthermore, the oxygen content of the atmosphere must be measured (by devices in the Dräger Polytron family, for example) in areas rendered inert. The price of LNG is constantly dropping due to the continuous development of production and transportation capacity for the fuel. This is another reason why it is of interest to the shipping industry.

Container ship, 18,000 TEUs

3

grams

Goods train

21grams

Truck, 40 tons

80grams

Plane

435grams

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THE BUILDING BLOCKS OF THE GLOBAL ECONOMY

Containers play an especially major role in the growth of shipping. The global capacity of container ships, expressed in twenty-foot

equivalent units (TEUs), is approximately 20 million in 2016. The global container

fleet (used for shipping) comprises around 40 million TEUs. The biggest container

ships in the world can now carry more than 18,000 TEUs – in 1967 the

figure was just 700.

Cars43.2%

HGVs and buses

19.3%

Railroad (without electrification)0.6%

Inland shipping1.4%

Motorbikes0.9%

Inland aviation1.4%

Other forms of transport

0.9%

International shipping

12% International aviation11.6%

LGVs8.7%

HOW MUCH GREENHOUSE GASES ARE EMITTED BY EACH

TRANSPORT SECTOR?

Figures for the European Union (as of 2013):

HOW MUCH SULFUR IS THERE IN EACH FUEL?

LNG

0.0PERCENT

TRUCK DIESEL

0.001 PERCENT

MARINE DIESEL LSMGO

(Ports)

0.1 PERCENT

HEAVY FUEL OIL – LOW-SULFUR IFO 380

(Emission Control Areas, ECA)

1.0 PERCENT

HEAVY FUEL OIL – IFO 380

(Open sea)

2.5 PERCENT

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