The objective for the next decades is to have humans on Mars, but before this different steps have to be successfully completed: many of them involve the Moon, that due to its proximity is the ideal place to test the key technologies. As the transport capability of the resources is limited, one of the problems to be addressed it how to exploit what there is on that celestial bodies surface: in particular, this research work makes a step forward in the extraction of water from the lunar regolith by means of a carbothermal reduction. It is a novel process compared to other similar investigations, and so it needs to be carefully characterized: the modeling and testing of a laboratory demonstrator plant, that can be contextualized between Phase C and D of the life cycle, is presented, contributing to pass from a coarse preliminary design to a finer definition of the process parameters and the procedures to follow. The first aspect considered is the characterization of the lunar simulant, useful to analyze the process results and set up the preparation procedures. Then, it is presented an updated view of the main reaction characteristics, that involves the reaction of CH4, H2 and of the coke deposited during the process with the simulant: it is done from a thermodynamic point of view, defining which are the species that react and which is their relative contribution to the total yield, and from the kinetic one, so modeling in which way the reaction occurs and defining which is the main furnace outlet composition. This last information is useful for the methanation catalytic reactor, that needed the definition of some design parameters and the critical analysis of the catalyst performances, plus giving important information on how the flowing gas mixture is converted in water and methane. Finally, an exhaustive experimental campaign set up is presented: as soon as the access to the facility is guaranteed, the tests can start. Thus, this work constitutes a solid base to continue the investigation on the laboratory plant and on the reaction process, and then to start the same refinement work on the scaled lunar plant, that is also at a preliminary design level.
L'obiettivo dei prossimi decenni è quello di portare gli umani su Marte: ci sono diversi step da completare con successo, e molti di questi comprendono la Luna, che grazie alla vicinanza la rendono il posto ideale dove testare le tecnologie chiave. Poiché le capacità di trasporto sono limitate, uno dei problemi da affrontare è lo sfruttamento delle risorse lì presenti: in particolare, questo lavoro di ricerca compie un passo avanti nell'estrazione di acqua dalla regolite lunare grazie ad una reazione carbotermica. É un processo innovativo comparato con altre investigazioni simili, e quindi deve essere caratterizzato: vengono presentati la modellazione e i test di un impianto dimostrativo di laboratorio, che può essere contestualizzato tra la Fase C e D del ciclo di vita, contribuendo a passare da un design preliminare and una definizione più fine dei parametri di processo e delle procedure da seguire. Il primo aspetto considerato è la caratterizzazione del simulante lunare, utile per analizzare i risultati del processo e impostare le procedure di preparazione. Successivamente, è presentata una visione aggiornata della reazione principale, che coinvolge la reazione del simulante con CH4, H2 e carbonio depositato durante il processo: ciò è fatto dal punto di vista della termodinamica, definendo quali sono le specie che reagiscono e il loro contributo relativo all'efficienza totale, e da quello cinetico, modellando quindi come le reazioni avvengono e definendo la composizione in uscita dal reattore principale. Quest'ultima informazione è utile per il reattore catalitico di metanazione, che aveva bisogno della definizione di alcuni parametri di design e dell'analisi critica delle performance del catalizzatore, oltre a dare importanti informazioni su come i gas flussanti vengono convertiti in acqua e metano. Infine, è presentata l’impostazione della campagna sperimentale: quando l'impianto tornerà fruibile, i test potranno cominciare. Questo lavoro costituisce una base solida per continuare l'investigazione sull'impianto di laboratorio e sulla reazione, e successivamente per raffinare l'impianto lunare scalato, anch'esso in fase preliminare di progettazione.
Water extraction from lunar regolith by carbothermal reduction : ISRU demonstrator plant modeling and testing
TROISI, IVAN
2018/2019
Abstract
The objective for the next decades is to have humans on Mars, but before this different steps have to be successfully completed: many of them involve the Moon, that due to its proximity is the ideal place to test the key technologies. As the transport capability of the resources is limited, one of the problems to be addressed it how to exploit what there is on that celestial bodies surface: in particular, this research work makes a step forward in the extraction of water from the lunar regolith by means of a carbothermal reduction. It is a novel process compared to other similar investigations, and so it needs to be carefully characterized: the modeling and testing of a laboratory demonstrator plant, that can be contextualized between Phase C and D of the life cycle, is presented, contributing to pass from a coarse preliminary design to a finer definition of the process parameters and the procedures to follow. The first aspect considered is the characterization of the lunar simulant, useful to analyze the process results and set up the preparation procedures. Then, it is presented an updated view of the main reaction characteristics, that involves the reaction of CH4, H2 and of the coke deposited during the process with the simulant: it is done from a thermodynamic point of view, defining which are the species that react and which is their relative contribution to the total yield, and from the kinetic one, so modeling in which way the reaction occurs and defining which is the main furnace outlet composition. This last information is useful for the methanation catalytic reactor, that needed the definition of some design parameters and the critical analysis of the catalyst performances, plus giving important information on how the flowing gas mixture is converted in water and methane. Finally, an exhaustive experimental campaign set up is presented: as soon as the access to the facility is guaranteed, the tests can start. Thus, this work constitutes a solid base to continue the investigation on the laboratory plant and on the reaction process, and then to start the same refinement work on the scaled lunar plant, that is also at a preliminary design level.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/154601