Frequently Asked Questions

HYDROGEN’S MAIN CHARACTERISTICS:

WHY HYDROGEN?

Almost all energy sources contain carbon and hydrogen, although, as time passes, a declining ratio of carbon and an increasing hydrogen ratio are introduced into the energy mix. For this reason, renewable hydrogen is the final step of an energy shift away from carbon that has a history of 200 years - since the industrial revolution made use of coal.

WHERE CAN WE FIND IT?

Hydrogen can be found in stars that use it as fuel to produce energy and in “empty” spaces between the stars. On Earth, it does not typically exist by itself in nature and must be produced from compounds that contain it, for instance, from water (H2O). Hydrogen is believed to be one of three elements produced in the Big Bang and the only element that can exist without neutrons. We owe most of the energy on our planet to hydrogen because the Sun’s nuclear fusion process converts hydrogen to helium releasing large amounts of energy. Hydrogen was used as a fuel for the rocket (Saturn V) that carried the first astronauts to the moon.

HYDROGEN CARRIER

Since hydrogen is the smallest and lightest molecule in the universe, it is not easily stored in large quantities. High pressured vessels or cryogenic tanks are required, making it only economical for smaller storage sizes. Ammonia is in this respect a good solution as carrier for hydrogen as it is easier to store, meaning that ammonia can be used as a more dense energy carrier. The energy density per volume of ammonia is 35% higher compared to liquid hydrogen, while the storage is just -33°C compared to the cryogenic requirement for liquid hydrogen of -253°C.

After trans-shipment, ammonia can be converted back to hydrogen via a thermo-catalytic process also known as ammonia cracking. This process requires energy input and results in inevitable energy loss. Typically, after ammonia cracking, the hydrogen stream will be harvested and used for further applications and the nitrogen stream will be directly vented to the atmosphere.

AMMONIA COMBUSTION

Many of the proposed novel applications of low carbon ammonia are based on combustion. Compared to carbon-containing synthetic fuels (e.g., methanol, biodiesel, synthetic methane), ammonia combustion is carbon-free with no direct greenhouse gas effect from CO2. Although ammonia combustion is a good solution from a sustainability point of view, it has some challenges which need the required attention. When using ammonia, combustion there are two things to be aware of.

AMMONIA SLIP & FORMATION OF N₂O AND NO_X

Ammonia slip results from the difficulty of maintaining stable combustion, which can result in uncombusted ammonia being directly emitted with exhaust gas. The formation of nitrous oxide and nitrogen oxide results from complex combustion chemistry. Applied research is required to address these topics. CMB.TECH and the Swiss marine power company WinGD have signed an

agreement on the development of ammonia-fuelled two stroke engines.

IGNITION PROPERTIES

First, ammonia is harder to ignite than hydrogen and hydrocarbon fuels because of its relatively high auto-ignition temperature. In many cases, this can be addressed by initiating combustion with a more easily ignited fuel and then transitioning to pure ammonia fuel. Ammonia combustion in furnaces is currently being tested with coal co-firing in Japan.

Industrial processes with furnaces typically use enriched oxygen (O2) or multi-stage air injection to address the ignition and combustion challenges. In all cases, this adds complexity to the engine/furnace design and potentially to fuel management.

MARINE FUEL

CMB.TECH believes that green hydrogen (for small ships)and green ammonia (for large ocean going ships) canplay an important role to decarbonize the shippingindustry.

Newcastlemax Bulk Carriers

The integration of the drivetrain, the storage and thebunkering of hydrogen and ammonia, is implemented witha diverse and experienced in-house engineering team inpartnership with Original equipment manufacturer andshipyards.

Stainless Steel Chemical Tankers

CMB is already building a future proof fleet with ammoniaClass Approval including bulk carriers, chemical tankersand container vessels on order, allowing a future retrofitfor using ammonia as a fuel without losing cargo capacity.

Container Vessels

frequently asked questions

Windhoek

Walvis Bay