Retrofit of first ultra-large container ship to burn LNG fuel could be first of many, while enginemaker plans delivery of an ammonia-burning engine by 2024
For over half a year, engineers, technicians and welders have been premanufacturing a membrane tank ashore at the HuaRun DaDong Dockyard in Shanghai. At the beginning of October, the tank was hoisted into the belly of Sajir, a 15,000-TEU container ship owned by Hapag-Lloyd, for installation.
When the ultra-large container ship (ULCS) Sajir steams out of the shipyard in early 2021, it will be among the biggest box ships modified to use LNG fuel, demonstrating the maturing bunkering infrastructure and growing commercial viability of the fuel.
Meanwhile MAN Energy Solutions, supplier of Sajir’s engine, has successfully concluded the type-approval test (TAT) for the LNG retrofit kit for the MAN 32/40 engine type. The company is planning to deliver an ammonia-burning engine for a project at South Korea’s Daewoo Shipbuilding & Marine Engineering (DSME) that has received approval in principle (AiP) from Lloyd’s Register (LR).
Ready to steam out in early 2021
Sajir’s bunker tank is a membrane tank designed by GTT. A membrane tank design was chosen for its lower boil-off gas (BOG) rate, allowing for the use of a smaller tank and more space for carrying cargo.
BOG management is achieved through auxiliary engines and the boiler. The vessel does not have a vapour return compressor for bunkering.
Prior to tank insertion, the container guide rails and other fixtures were removed from Hold 9 to make room for the tank. The vessel’s frames required no modification. The tank itself was premanufactured inside an exoskeleton as reinforcement. The tank was lifted and placed inside the cargo hold located directly forward of the main engine casing.
The gas storage system will use the space normally occupied by 290 TEU, which means the vessel’s container capacity will be lowered by the corresponding amount.
While the tank is welded to the hold, the main engine and the auxiliary diesel engines will be converted to dual-fuel operation for LNG and very low sulphur fuel oil (VLSFO). The process of retrofitting Sajir for LNG propulsion began on 2 September at the shipyard.
Plans call for Sajir to complete its conversion phase and initial test voyages in early 2021 before being redeployed in the Asia-North Europe trade lane. It will then bunker twice every round voyage – once in Rotterdam and once in Singapore.
The conversion came with a hefty price tag of US$35M, but it is a key element of Hapag-Lloyd’s sustainability strategy. Using LNG has the potential to reduce CO2 emissions by 15% to 30% and SOx and particulate matter emissions by more than 90%.
“With this unique pilot project, we hope to learn for the future and to pave the way for large ships to be retrofitted to use this promising alternative fuel,” says Hapag-Lloyd fleet managing director Richard von Berlepsch. “However, our long-term goal continues to be CO2-neutral shipping operations using synthetic natural gas (SNG),” adds Mr von Berlepsch.
Sajir is one of 17 vessels in Hapag-Lloyd’s fleet that were originally designed to be LNG-ready, meaning its 16 sister ships are also technically prepared for retrofitting.
“We believe in gas as one of the most promising pathways into an environmentally friendly future,” says Mr von Berlepsch. “Our midterm target is to operate these vessels on synthetic natural gas which would allow the ships to be carbon neutral. This of course depends on the future development of gas infrastructure,” he says.
The gas handling equipment is located inside the cargo hold on top of the membrane bunker tank. All crew members that sail on Sajir will undergo extensive training, learning how to handle LNG before going on board the vessel, complying with all requirements and laws, say Hapag-Lloyd representatives.
Besides crew training and a new gas supply system, Sajir’s existing MAN B&W engine is undergoing modification to dual-fuel capability. Once converted, the Diesel-cycle, two-stroke 9S90ME-C10.2 will be a 9S90ME-C10.5GI. Main components including high-pressure fuel pipes, cylinder cover, cylinder liners and piston crowns and rings will be replaced, with new components such as gas injectors, gas control block, adaptor block, gas chain pipes, sealing oil system, and GI(E) control system being installed.
The engine power will remain the same as will its Tier II performance. Retrofit projects are not considered ’major conversions’ by class societies, meaning no extra abatement technology will be required. The new engine will still be oil-based having the same output but with the ability to operate on LNG, lowering NOx emissions by 30% and SOx emissions by over 90%. CO2 emissions will be lowered by 24%, say MAN Energy Solutions representatives.
Dual-fuel kit ready
Meanwhile, MAN Energy Solutions (MAN ES) is hard at work on LNG conversion kits for the existing fleet. The engine designer announced the successful conclusion of the TAT for its dual-fuel retrofit kit for its MAN 32/40 engine type. The TAT took place at the company’s Augsburg, Germany works in September with the participation of three classification societies: DNV GL, ABS and Lloyd’s Register. The retrofit package is available to order.
On account of the Covid-19 pandemic, the TAT was primarily held online. Classification-society representatives followed proceedings remotely and only visited the test bed on the final day for component inspection and TAT certificate signing.
MAN ES says it has received many requests from customers to retrofit their MAN 32/40CD engines to gas/dual-fuel operation. The new retrofit meets IMO Tier I emission limits and has been designed such that engine conversions can be carried out while drydocking or sailing.
In a first step, MAN ES plans to convert engine type 32/40 into 32/40R-DF only on Tier I emissions limits so as to reduce the conversion cost to a minimum since no, or perhaps fewer, combustion and injection parts will be required in the converted engine. The intent is to keep the existing IMO certification for the engines to provide a price-competitive, quick-to-convert solution, say company representatives.
Tier II and III conversions will be developed with customer acceptance, they say.
The current engine release is with HFO/MGO/MDO in liquid mode and LNG in gas mode. New bio/future fuels will be introduced in future.
As the 32/40R-DF is not a full DF-engine with pilot fuel injector, so as to meet cost and quick-to-convert objectives, the current fuel flex technology uses the existing main injector for gas inflation into the combustion chamber. Consequently, the engine will provide 400kW/cyl at the typical load point of 80% MCR in gas mode with 70% gas and 30% diesel. 100% MCR with 500kW/cyl is available only in liquid mode. This is the reason for Tier I as the engine will not be able to run in 100% gas mode today.
Development of 32/40R-DF to achieve Tier II and Tier III norms is expected, MAN Energy Solutions adds.
Ammonia engine by 2024
Work on future fuels is continuing, and, if MAN ES project’s timelines are an indication, an ammonia-burning engine will be ready for delivery to a shipyard in 2024.
Lloyd’s Register has granted DSME an AiP on a joint project with MAN Energy Solutions for an ammonia-powered 23,000-TEU ULCS design. The AiP marks the first phase of the joint project, which has been underway since June 2019. As part of the project, DSME generated the basic design for the ammonia-based propulsion system and MAN was responsible for the development and specifications of the ammonia dual-fuel engine.
LR reviewed the suitability and risks of the design which involved a hazard identification workshop, a hazard and operability analysis workshop and a design review in accordance with the approval of risk-based design process, which led to the AiP.
Following this, a second phase will involve further development of the design for meeting market demand in terms of commercial viability as well as technical and safety maturity.
DSME vice president and chief technical officer Odin Kwon says the ship’s design was more complex than other ship types because the ammonia fuel tank and much of the fuel facility and safety equipment is installed in an enclosed space. He adds “The successful results from the joint AiP can easily be applied to other type of vessels such as tankers, bulk carriers and gas carriers. We now just await the delivery of the ammonia-fuelled engine from MAN Energy Solutions.”
MAN ES has completed ammonia combustion studies. The 4T50ME-X test engine has been designated as the platform for ammonia engine development. Full-scale engine testing is expected at the company’s Copenhagen facility in 2023. By 2024, an ammonia burning engine is scheduled for delivery to the yard.
The ammonia fuel system will have to be designed to handle ammonia’s corrosiveness and ammonia bunker tank sizes will have to be designed to accommodate the need for vessel endurance factoring in that ammonia’s energy density at 18.6 MJ/kg is much less than that of conventional bunker oil.
MAN ES plans to have an ammonia retrofit kit, too. On burning ammonia in the engine through a retrofit, MAN ES representatives say they expect the power to remain at the same level, but this would be less of a concern since the majority of ship designs today employ two-stroke engines that are derated significantly on mean effective pressure, with plenty of ’head room’ for uprating should that become necessary.
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