With the global LNG trade predicted to grow seven times faster than pipeline gas, BP Shipping’s new Partnership class vessels are an invaluable addition to the fleet.
Bigger, more powerful, with a much larger carrying capacity than their predecessors. But also more efficient and, therefore, more environmentally-friendly and cost-effective, with greater flexibility in terms of the places where they can operate. All of which makes them more competitive in a rapidly-changing marketplace.
It is easy to see why BP’s new ‘Partnership’ class of LNG carriers is creating such a buzz among the business’s shore-based and seafaring staff around the world.
The ships are the most fuel-efficient and technically advanced LNG tankers ever built for BP. They will also significantly increase BP’s ability to safely transport LNG around the world – not just to established markets, such as India, China, the US and Australia, which are all enjoying substantial growth, but also in emerging new markets, such as Pakistan, Jordan, Egypt and Bangladesh, where consumer demand is increasing rapidly.
This enables the shipping business to further support BP’s global strategy to grow its natural gas portfolio as an alternative energy source to coal and as a partner for renewables.
“BP is set to increase its LNG supply significantly over the next four years thanks, largely, to new projects in the US, and off the coast of Mozambique,” explains Oli Beavon, technical vice president for BP Shipping. “The new Partnership class ships will give us the necessary capacity to transport those extra volumes around the world.”
Each of the new vessels is fitted with two, next-generation M-type, electronically-controlled, gas-injection (ME-GI) propulsion systems and a proprietary full reliquefaction system (FRS) designed by the Korean shipbuilders, DSME.
The ‘slow speed’ tri-fuel engines, each of which has its own shaft, propeller and rudder, use compressed ‘boil-off’ gas from cargo tanks as fuel. “The cargo on an LNG vessel will slowly warm up if gas vapour is not pulled off the top to keep the remaining liquid cool,” explains Sandy Farquhar, BP Shipping’s site construction manager. “It is a bit like your body sweating and that evaporation keeping you cool.
“This gas vapour is called boil-off, and it becomes a useable lower carbon commodity to replace fuel oil.”
Older LNG carriers would use this boil-off gas to power either steam turbine or dual fuel/diesel electric engines. But the Partnership vessels have a five-stage compressor that raises the pressure of the gas from just above atmospheric pressure to 300bar. It is then sent to the engines for fuel – or to the reliquefaction system.
When the re-liqufaction plant is in use, up to 70% of the gas discharged from the compressor is cooled to a temperature where it returns to liquid form. This is then pumped back to the cargo tanks, allowing the ships to deliver more LNG to the market.
It all adds up to an easy-to-operate system, which burns less cargo gas than its predecessors and improves fuel efficiency by around 25%.
Greener, safer, better
It is not just the engines that contribute to greater efficiency in the new Partnership class LNG tankers. The vessels also feature significant improvements in hull design, which improve speed and manoeuvrability.
The ships environmental credentials are impressive too. Compared to the older vessels that they have replaced in the BP fleet, an exhaust gas recirculation system reduces nitrogen oxide emissions and the gas combustion system on board minimizes the potential for releasing methane to the atmosphere.
For waste management, engine room sludges and waste water is processed to minimize the use of the incinerator and galley waste passes through a macerator and shredder, producing slurry that is retained in a tank until it can be safely discharged. Dry waste is treated with high-duty shredders, glass crushers and a compactor for baling and landing ashore minimizing ship discharges.
Safety is inherent in the design too. To minimise the threat of piracy, the crew accommodation and engine room structures are designed and built to make it extremely difficult for potential attackers to gain access. Some of the measures adopted include the removal of external means of access to the ship’s bridge and other decks and the provision of metal shutters to external windows. The measures taken effectively turn these structures into a ‘citadel’ or safe area for the ship’s crew to retreat to if attacked.
Tighter cost control
While BP’s LNG business has grown by 30% in the past year, margins are eroding. To be competitive, therefore, it is vital that the new LNG carriers are also cost-effective. “The kind of market growth we are seeing has inevitably led to increased competition,” says Jonty Shepard, chief operating officer for LNG, at BP supply and trading. “Profit margins are dropping off as the big trading houses start to get involved in LNG for the first time.”
The size and greater efficiency of the Partnership class tankers help significantly in this respect, as larger cargoes can be transported at significantly lower unit costs than previously.
Flexible for facilities
Port access is a major issue with some LNG operators, and BP’s new Partnership class tankers will have a significant advantage in this regard.
While they have deliberately been built big enough to take advantage of the 2016 Panama Canal enlargement – a major global transit route for LNG – their design, technology and environmental improvements mean they are also far more nimble than their Trader and Gem class predecessors.
This means they will be able to load and discharge cargoes at a far wider range of LNG ports and floating facilities worldwide, including those that are just coming on line.
Fit for the future
Around half of BP’s upstream portfolio is currently gas, and the business expects that to grow as more major projects come online. Natural gas, and LNG in particular, will form a major part of this growth – the 'Evolving Transition' scenario in BP's 2017 Energy Outlook forecasts that global LNG trade will grow seven times faster than pipeline gas trade. And the new Partnership class carriers will play a vital role in transporting these increased volumes safely and efficiently from the points of production to customers.
Read the article online at: https://www.lngindustry.com/liquid-natural-gas/19072018/new-gas-ships-set-sail-with-latest-technology/
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