Exhibition & Conference

13-16 September 2021

Singapore EXPO, Singapore

Technical Programme

René Sejer Laursen

Promotion Manager ME-GI & ME-LGI

MAN Energy Solutions

17:00 - 17:30

Tuesday, 17 September 2019

T1.2 The multi-fuel two-stroke MAN B&W dual fuel engine



Over the past six years, MAN Energy Solutions has introduced new types of dual fuel engines that are capable of burning LNG, methanol, ethane gas, and LPG. Lately, discussions have started about how low-carbon fuels can be used for shipping. MAN Energy Solutions is therefore looking into combining the engine technology so that various types of gas fuels can be used on the same engine.                                                                      

The paper describes the multi-fuel engine technologies that we offer for propulsion of merchant ships as well as the challenges that we face when developing a dual fuel engine for operation on both LNG, LPG and LEG. The base fuel for this multi-fuel engine is still conventional fuel oil, so in reality the engine will be able to burn a variety of fuel oils as well.

Today, bunkering of LNG is still limited worldwide. MAN Energy Solution had expected that bunkering facilities would have been established within a significantly shorter time. This has not happened, so the goal for this engine development is to achieve a faster acceptance of the use of gas fuel worldwide. In areas where the LNG is not available, we have found that LPG would be a better option. In the future, we expect also that ethane will be made available as a bunker fuel. In areas where all three gas fuels are available, the multi-fuel engine will offer significant flexibility in fuel choice. The owner will have the option to select the cheapest fuel available among the gas fuels, including fuel oils.

Using LPG and LEG as fuel on the two-stroke ME-GI engine offers similar emission benefits as using LNG. With this engine, technology efficiencies above 50% can be achieved independent of which fuel is selected. And all the different gas fuels reduce emissions significantly compared with MDO.

When selecting gas fuels as the primary fuel, the energy efficiency design index (EEDI) values can be reduced by 20% compared to MDO, so many ships can simply apply gas fuels in order to meet the future EEDI requirement. This multi-fuel injection system, which basically is the core new development in the new engine system, can be applied on all engine sizes from 5 MW to 90 MW. This power range is suitable for tankers, bulk carriers, container vessels, etc. The injection system can also be applied on MAN B&W stationary engine types, thereby offering extensive fuel flexibility for power plants.

This paper describes the technology applied for delivering gas to multi-fuel MAN B&W two-stroke engines operating on LNG, LPG and LEG as fuel. There have been significant challenges in designing a fuel gas supply system design for a multi-fuel engine, but we have managed to develop a design consisting of just one fuel gas supply system that can handle all three gas-fuel types. The special requirements to the tank design, including its installation on different ship designs, will also be described.