Liquid ammonia and methanol can become the future fuel in deep sea shipping

During my PhD I will perform fundamental combustion research on carbon neutral and low carbon fuels for marine combustion engines.

David Zilles doing experiments in the EPT-Lab
David Zilles is doing experiments to find the best ignition technology for ammonia and methanol fuel in ship engines. Photo: Maren Agdestein/ NTNU

This is a blog post. The opinions expressed here are those of the author.

Written by
En mann
David Zilles PhD Candidate

Liquid ammonia and methanol are currently the most promising liquids for machines run by renewable energy. They combine a relatively high energy density with attractive possibilities for a production from green or regenerative energy.

The marine industry must head towards zero or low emission engines when we move towards a carbon free society. International shipping is estimated to produce around 3 percent of our worldwide CO2-emissions.

Challenges that must be overcome

Current marine engines cannot burn ammonia and methanol since their physical properties are very different to conventional marine fuels. A low reactivity, and more specific, slow flame speeds and high minimum ignition energies are one of the challenges that must be overcome.

David Zilles, doktorgradsstudent, i maskinlaboratorie.
Base research is important to achieve carbon free marine engines in the near future. Photo: Maren Agdestein/ NTNU.

One option is to combine these fuels with a high reactive fuel as ignition promoter. This can be conventional diesel fuel or n-heptane which is a laboratory surrogate.

I will investigate experimentally the minimum n-heptane quantity which is necessary to combust reliable liquid ammonia and methanol in a dual fuel direct injection combustion strategy.

Measuring the ignition delay in a constant volume combustion chamber will help to describe the combustion process of these new fuels. 

Towards carbon free fuels

In foreseen future no alternative propulsion technology will reach the energy density of our liquid fuels burning in engines. Long distance and heavy-duty ships rely therefore on the development of combustion strategies for carbon free fuels.

  • The International Maritime Organization (IMO), which is the UN body for regulating maritime transport, set a goal of reducing carbon emissions by 40 percent by 2030 in 2018.
  • Greenhouse gas emissions should be reduced by 50 percent by 2050 with the level in 2008 as a baseline.
  • Now there is intense research on ship engines with other types of fuel, ships with better propulsion and new types of sails. Constructions that mimic the fins of marine animals have also been developed by students and researchers at NTNU for the great transition that must take place.
  • Next year, a carbon quota system for shipping will be introduced in the EU, and Norway’s CO2 tax will rise towards 2030.

Big marine engines have a lifetime of 25-30 years.

It is important to enable a fast and easy retrofit from fossil heavy fuels to methanol or ammonia to reduce the impact on climate change of these huge machines.

By characterizing ammonia and methanol for an application in marine combustion engines I support the maritime industry during the transition to more climate friendly propulsion systems for the global trait of goods.

It enables a sustainable economic growth while reaching emission legislations for the marine transport sector, reducing their impact on climate change.

I started my research in the beginning of this year and will continue until 2026. My work is fully funded by the Department of Marine Technology at NTNU. My experimental test rig, the Combustion Research Unit is lent from Fueltech Solutions AS, Trondheim.

About the blog author

Portrait of David Zilles, PhD candidate at the Department of Marine Technology
David Zilles

David Zilles is a PhD candidate at NTNU – Department of Marine Technology with a project fully funded by the department. His main supervisor is David Emberson and his co-supervisor is Eilif Pedersen, both from the Department of Marine Technology.