Inland waterway vessel concept with ammonia propulsion system

The inland waterway transport sector faces challenges such as digitalization, adaptation to climate change and the integration of alternative propulsion technologies. Given the long service life of ships, the targets agreed in the Mannheim Declaration for reducing air pollutant and greenhouse gas emissions and the taxonomy screening criteria require the rapid development of measures to increase environmental sustainability. Simply further improving the already inherently good efficiency of shipping is not enough. The introduction of the EU Emissions Trading System, the Corporate Sustainability Reporting Directive and approaches currently being developed to assess greenhouse gas intensity of inland waterway transport will further promote the avoidance of CO2 and other greenhouse gases. Today, fossil diesel fuel is still widely used in inland waterway transport. The bio-based fuel HVO has also been available for some time, but its availability is limited by the need for sustainable feedstock. A large number of pilot projects have been launched in recent years with the alternative energy sources hydrogen and methanol, as well as batteries. As no clear trend towards a particular technology is yet apparent, other options such as ammonia are being considered in the sector. Ammonia is also a suitable storage and transport medium for renewable green hydrogen. However, the combustion properties and safety requirements of ammonia pose major challenges for its use as a motor fuel. The CAMPFIRE consortium is running several projects on the conversion and storage of green ammonia as part of future energy systems. One of these projects is developing a propulsion system for inland waterway vessels that runs on pure ammonia as fuel. The main components of this system are an ammonia cracker, which converts a partial flow of the fuel into hydrogen, and a high-speed combustion engine that runs on liquid ammonia and a small amount of hydrogen as an ignition enhancer. The CAMPFIRE Open Innovation Lab (COIL) is currently being built in Poppendorf near Rostock to test the technologies developed. Various configurations (ignition, injection, combustion chamber design, etc.) were tested and evaluated as part of systematic combustion process investigations for the engine as the central energy converter for ship propulsion. The engine achieves comparable performance values and efficiencies to the conventionally operated basic diesel engine. An exhaust gas aftertreatment system will be used to comply with emission limits. It can be assumed that this system can consist of already known technologies. Based on the results obtained, a concept for a prototype engine was derived, which will be examined in detail at COIL in conjunction with the ammonia cracker. The use of ammonia as a fuel also leads to new requirements for ship design. Due to the hazardous substance classification of ammonia and the potential environmental hazard, appropriate safety precautions must be taken. Using the example of an existing ammonia tanker that operates on the Rhine and its tributaries, a concept was developed for the integration of the above-mentioned propulsion system, including the fuel tank and the fuel treatment system. The planning of the conversion of the inland vessel, taking into account the necessary safety measures, was evaluated as part of a risk analysis.