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Liquefied natural gas (LNG) is stored at a cryogenic temperatures ≤ -160°C and around atmospheric pressure to insure the minimum storage volume in tanks. The demand for LNG has been increasing as a primary source of energy. Therefore, there is significant interest in the construction of LNG tanks to achieve low cost and safe storage. Three systems are typically used to store LNG: single containment, double containment, and full containment. Concrete is used in these containment systems, and consequently, understanding concrete behavior and properties at cryogenic temperatures is important. The research documented in this thesis deals with computational analysis of the behavior of concrete subjected to cryogenic temperatures. The analysis focuses on the effect of aggregate sizes, coefficient of thermal expansion, volume fraction, and the shape of aggregate on damage of concrete subjected to cryogenic temperatures. The analysis is performed by developing a computational model using the finite element software ABAQUS. In this model, concrete is considered as a 3- phase composite material in a meso-scale structure: mortar matrix, aggregate, and interfacial transmission zone (ITZ). The Concrete Damage Plasticity model in ABAQUS is used to represent the mortar and ITZ phases of concrete. This model has the advantage of accounting for the effect of temperature on material properties. The aggregate phase is modeled as a linear-elastic material. The model parameters are selected based on comprehensive literature review of material properties at different temperatures. The finite element results provide very useful insight on the effects of concrete mixture design and properties on resistance to damage. The most important factor that affected damage development was the difference in the coefficient of thermal expansion between the mortar and aggregates. Models in which the mortar and aggregate had close values of positive coefficients experienced less damage. The model with irregular shape particles experienced more localized damage than the model with circular shape particles. The model was successful in demonstrating the effect of using air entrained concrete in reducing damage. The damage results predicted by the model for air entrained and non-air entrained concrete are validated by comparing them with experimental data from the literature. The analysis validated the capabilities of the mode in simulating the effect of reduction in temperature on damage. The modeling results and the findings from the literature review were used to put forward recommendations regarding the characteristics of concrete used in LNG storage.

Today, the world faces an energy source transformation that is difficult to grasp. To convert to a green energy society, carbon, oil, and natural gas must faze out as fuels during the upcoming decades. Hydrogen gas has received a lot of attention in recent years regarding the challenges in the energy sector, not only because of its multifunctionality as a fuel but also because it is a great energy carrier. The largest part of the green hydrogen gas produced in the future will be made in locations with great possibilities to produce hydrogen gas from solar energy. This means that a huge amount of this will need to be transported (and stored correctly during transportation) to countries with an increased industrial need for hydrogen but with insufficient production of hydrogen. The report will cover two different ways of transporting hydrogen gas. The first one is intermodal transport of tubes (hydrogen gas) or tanks (cryogenic hydrogen), and the second one is through pipelines. The report will also investigate two different ways of storing hydrogen, as a cryogenic liquid or as a compressed gas. The report will also investigate the production of intermodal commodities for compressed hydrogen gas where a material selection will be made to optimise the possibilities to store and transport hydrogen gas. The material selection analysis showed that a duplex stainless steel was the best material for hydrogen gas tubes. From the result, it is clear that compressed hydrogen gas in tube containers is the cheapest transport method with respect to both Operational Expenses (OpEx) and Capital Investment Expenses (CapEx). / Idag står världen inför en energiomställning med stora hinder. För att ställa om till ett samhälle med grön energi står det klart att kol, olja och naturgas måste fasas ut som bränslen under de kommande decennierna. Vätgas har fått mycket uppmärksamhet under de senaste åren när det gäller utmaningarna inom energisektorn, inte bara på grund av dess multifunktionalitet som bränsle utan också för att det är en utmärkt energibärare. Den största delen av den gröna vätgas som produceras i framtiden kommer att tillverkas på platser med stora möjligheter att producera vätgas från solenergi. Detta innebär att en enorm mängd av detta kommer att behöva transporteras (och lagras korrekt under transporten) till länder med ett ökat industriellt behov av vätgas men med otillräcklig produktion av vätgas. Rapporten kommer att omfatta två olika sätt att transportera vätgas. Det första är intermodal transport av tuber (vätgas) eller tankar (kryogen vätgas), och det andra är genom rörledningar. Rapporten kommer också att undersöka två olika sätt att lagra vätgas, som en kryogen vätska eller som en komprimerad gas. Rapporten kommer också att undersöka produktionen av intermodala råvaror för komprimerad vätgas där ett materialval kommer att göras för att optimera möjligheterna att lagra och transportera vätgas. Materialvalsanalysen visade att duplex rostfritt stål var det bästa materialet för vätgastuber. Av resultatet framgår det tydligt att komprimerad vätgas i rörbehållare är den billigaste transportmetoden med avseende på både Operational Expenses (OpEx) och Capital Investment Expenses (CapEx).