STUDY OF THE TECHNICAL FEASIBILITY OF A “LOHC HYDROGEN STORAGE AND SOFC” SYSTEM FOR AIRCRAFT APPLICATION

Today, global warming has reached alarming levels and will only worsen if greenhouse gas emissions are not reduced. Of all types of transport, aviation is the most polluting. A solution for decarbonizing the aerospace industry is represented by hydrogen, thanks to its high gravimetric energy density. However, the main challenge of H2 is related to its storage. Due to its very low density, H2 is not competitive in the transport sector. Thus, to increase its density, technologies such as compressed hydrogen, liquified hydrogen, liquid organic hydrogen carriers and metal hydrides are used. The fuel cell system is another key component in the decarbonization scenarios. Indeed, thanks to it, electrical power is generated without pollutant emissions. The aim of this thesis is to eliminate CO2 emissions from aircrafts. For this reason, the “ATR-72 600” propulsion will be made completely electric thanks to the use of an SOFC system. The fuel will be hydrogen stored in “perhydro-dibenzyltoluene”, a well-known LOHC technology. The various storage technologies will be discussed in great depth, explaining their properties, dynamic behavior and hydrogen release processes. Then, the characteristics and dynamic behavior of the fuel cell mentioned above will be studied. Once the most promising storage and fuel cell will be chosen, they will be coupled and modeled through Aspen Plus. Then the weight of the whole system will be evaluated and a sensitivity analysis, by changing the parameters of the fuel cell, will be carried out to reduce the system weight as much as possible. Finally, a gravimetric index, related to the H2 storage and releasing system, will be calculated to make a comparison with other commercial H2 storage systems. Unfortunately, the all-electric case of an “ATR-72 600” is not feasible, because of the space and weight requirements of the balance of plant components. Moreover, the airflow required for the fuel cell stack and the system cooling, would involve a large air intake in the fuselage, which would greatly modify the aerodynamics of the aircraft. For this reason, some degree of hybridization must be examined.