Kawasaki Completes World’s First Basic Engineering Works for Hydrogen Marine Main Boiler

May 31, 2022

Schematic of the completed marine main boiler

Tokyo, May 31, 2022-Kawasaki Heavy Industries, Ltd. announced today the completion of the world’s first basic engineering works for a hydrogen marine main boiler.

Kawasaki has delivered many propulsion marine main boilers for liquefied natural gas (LNG) carriers. Based on these technologies, it has developed its own hydrogen combustion technology for the new hydrogen marine main boiler. The boiler design incorporates particular technologies required for marine main boilers such as a structural design for vessel motion and compactness, distinguishing it from small once-through hydrogen boiler for land use. Kawasaki has already obtained approval in principle (AiP) from Nippon Kaiji Kyokai (ClassNK) for liquefied hydrogen carriers equipped with this boiler as the propulsion system.


As a demonstration of one of the core technologies of this boiler, in 2021 Kawasaki conducted a combustion test at a full-scale burner test station. This demonstration verified the high turndown ratio*1 compared with conventional LNG combustion burners.

The main features of Kawasaki’s hydrogen marine main boiler are as follows:

  1. Reliable and stable operation
    The basic design of the boiler furnace utilizes the combustion properties of hydrogen (high combustion temperature and speed), while applying the existing proven technical design of LNG-fired propulsion marine main boilers. Therefore, this boiler delivers reliable, long-term stable operation without requiring specific additional operations.
  2. Flexible response to load changes
    Marine main boilers must offer flexible operation under changing load to match fluctuations in sailing speed. This boiler features our outstanding hydrogen combustion technologies and know-how including combustion analysis refined through the development of hydrogen gas turbines.
  3. Flexible operation with several fuels
    The fuel of the boiler can be changed according to vessel operation mode. It allows mono-firing of hydrogen or low-sulfur fuels, as well as dual-firing.
  4. Safe and stable operation
    The technical advantages of our original hydrogen combustion burner ensure safe and stable operation of the hydrogen boiler. The burner design is based on a proven burner for LNG combustion, and ensures specified hydrogen-specific combustion properties, with safety considerations to prevent burnout and backfire.

This boiler, together with the steam turbine plant and fuel supply system, will be used in the dual fuel propulsion system of large-sized liquefied hydrogen carriers. The boiler can efficiently use boil-off gas (BOG) as fuel, which is generated by heat ingress during bulk transport of cryogenic liquefied hydrogen. Kawasaki plans to release this boiler for large-sized liquefied hydrogen carriers by the mid-2020s, and will continue to offer optimal boiler solutions to meet the growing demand for hydrogen in order to realize a sustainable and secure energy transition.

Furthermore, this marine main boiler technology can be used to upgrade gas-fired land boilers that use LNG, as well as several types of gases such as low calorific gas, BFG/COG, sour gas or associated gas. Hydrogen is expected to become a key energy source in many industries including oil & gas and chemicals, both in Japan and around the world, in order to decarbonize economic systems in the near future. For these industries, we will propose power systems utilizing our hydrogen fired boiler technologies for large-scale boiler plants, hydrogen mono-fired or dual-fired with LNG.

Kawasaki is paving the way for the hydrogen supply chain encompassing production, transportation, storage and utilization. This boiler will help realize the transportation and utilization of hydrogen. Kawasaki will continue to drive the technological development of the hydrogen society in order to promote the use of hydrogen energy and thus help to achieve decarbonization, working as one for the good of the planet.

Main specifications of Kawasaki’s hydrogen marine main boiler
Quantity 2 units per vessel
Steam quantity 70 t/h per unit
Steam pressure 5.9 MPaG
Steam temperature 530°C
Fuel Hydrogen, fuel oil / mono-firing or dual-firing

*1    Turndown ratio is a key metric of burner performance. A burner with a high turndown ratio offers stable, controlled combustion over a wide range.

Simulated appearance of the completed 160,000m3 liquefied hydrogen carrier

Related Links

Kawasaki Obtains AIP for Large, 160,000m3 Liquefied Hydrogen Carrier

ANSWERS (For Production, Transportation, Storage, and Utilization of Hydrogen at Lower Costs. Challenges to Commercialization)

Kawasaki Hydrogen Road – Paving the way for a hydrogen-based society –

Kawasaki Energy Plant


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