Feasibility study of a polygeneration plant for the production of hydrogen and liquefied natural gas

The transition towards a sustainable future requires a thorough analysis of energy sources and possible alternative fuels used in industries and in the transportation sector to address one of the main problem that affects them nowadays: the CO2 emissions. In a transitional and continuously changing energy scenario such as the one taking place nowadays, this paper aims to evaluate the techno-economic feasibility of a "green farm", a polygeneration fuel plant in Southern Italy, specifically in Sicily, with the peculiarity of being able to have a flexible production of renewable hydrogen, Liquefied Natural Gas and Bio Liquefied Natural Gas (Bio-LNG). The farm will be placed in Southern Italy, specifically in Sicily, a promising geographic area with significant industrial demand for hydrogen. The analysis begins with an overview of the current energy situation and the challenges associated with the use of traditional fossil fuels, highlighting their negative impact. After that, the advantages and disadvantages of hydrogen and LNG production are examined, focusing on production processes and fields of use. The core of the thesis is the technical sizing of the proposed plant, which includes, in particular, a liquifier plant for LNG and bioLNG production and a steam methane reformer for hydrogen generation. The peculiarity of this farm is the direct connection with an anaerobic digester plant that produces bio-methane. The bio-methane is the key element able to make the hydrogen production renewable and to produce bio-LNG. Key design parameters, technologies involved and plant efficiency are examined. After the technical description of the plant, the analysis shifts towards the economic side, with a detailed assessment of investment costs, operating costs and potential revenues from the production and sale of hydrogen and LNG in the market. Finally, the last chapter addresses the important issue of the CO2 emissions produced during the operations of the plant. It has been analyzed how the CO2 can be captured and its subsequent liquefaction and utilization. In conclusion, this thesis provides the techno-economic feasibility of a hydrogen and LNG polygeneration plant, with an emphasis on the environmental sustainability and cost-effectiveness of such an investment. All this work has been done during a curricular internship at Greenture, a wholly owned subsidiary of Snam that aims to support the process of decarbonization of transportation and off-grid applications by fostering the deployment of of natural gas, biomethane, hydrogen and other sustainable fuel.