In the context of decarbonization and the growing need to reduce energy imports, biomethane represents a fundamental substitute for fossil fuels, so much so that, recently, new research projects have been launched to grow the European biomethane industry (CORDIS Projects Info Pack) and the RepowerEU plan has launched the challenge of producing 35 bcm (billion cubic meters, Billion Cubic Meters) of biomethane by 2030 within the Union (EBA, 2024). The aim of this thesis is to simulate, through the ADM1 model, in-situ hydrogenotrophic methanogenesis, by injecting green hydrogen (H2) into the anaerobic digestion (AD) reactor. To this end, the potential of various substrates in producing biomethane is investigated and the trend over time of the output variables is studied as the H2:CO2 ratio introduced varies. First, the model results are compared with those obtained from the laboratory activity carried out in Viola Corbellini's doctoral thesis (Corbellini, 2019). Subsequently, substrates are studied whose fractionation into carbohydrates, proteins and lipids has been theoretically hypothesized, in order to simulate different influencing factors in composition. Modifications to the equations and parameters, inserted in the original ADM1, have been made in order to build a model capable of returning trends over time that are as representative as possible of reality. Thanks to the equations that describe the biological process, as far as allowed, it is possible to predict with greater accuracy any inhibitions of the biomass, allowing to meet the needs of digestion in the real field. The advantage of being able to simulate the process, even before its application, is in fact to evaluate its stability, performance and the costs associated with its maintenance. Furthermore, the maximum volumetric percentage of hydrogen allowed in gas transport and distribution networks in various countries is examined. With reference to current regulations, it is possible to understand whether the biomethane produced can be directly injected into existing infrastructures or whether it requires further upgrading treatment. Finally, the dosage of acid and base required to maintain the controlled digestion pH, guaranteeing the activity of microorganisms, is also reported.
Nel contesto della decarbonizzazione e della necessità crescente di ridurre le importazioni energetiche, il biometano rappresenta un fondamentale sostituto ai combustibili fossili, tanto che, di recente, sono stati avviati nuovi progetti di ricerca per far crescere l’industria europea del biometano (Projects Info Pack di CORDIS) e il piano RepowerEU ha lanciato la sfida di produrre 35 bcm (miliardi di metri cubi, Billion Cubic Meters) di biometano entro il 2030 all’interno dell’Unione (EBA, 2024). L’obiettivo di questa tesi è simulare, tramite modello ADM1, la metanogenesi idrogenotrofa in-situ, immettendo idrogeno (H2) verde nel reattore di digestione anaerobica (DA). A tal fine si investiga la potenzialità di vari substrati nel produrre biometano e si studia l’andamento nel tempo delle variabili di output al variare del rapporto H2:CO2 immesso. Dapprima si confrontano i risultati modellistici con quelli ricavati dall’attività di laboratorio svolta nella tesi di dottorato di Viola Corbellini (Corbellini, 2019). In seguito si studiano substrati il cui frazionamento in carboidrati, proteine e lipidi è stato ipotizzato in via teorica, in modo da simulare influenti differenti in composizione. Modifiche alle equazioni e ai parametri, inseriti nell’ADM1 originale, sono state apportate allo scopo di costruire un modello in grado di restituire andamenti nel tempo il più rappresentativi possibile della realtà. Grazie alle equazioni che descrivono il processo biologico, fin dove consentito, si può in questo modo prevedere con più accuratezza eventuali inibizioni della biomassa, permettendo di sopperire alle esigenze della digestione in campo reale. Il vantaggio di poter simulare il processo, ancor prima della sua applicazione, è difatti valutarne la stabilità, la performance e i costi annessi al suo mantenimento. Inoltre, si prende in esame la massima percentuale volumetrica di idrogeno consentita nelle reti di trasporto e di distribuzione del gas in vari Paesi. Con riferimento alle normative vigenti, si può così comprendere se il biometano prodotto può essere immesso direttamente nelle infrastrutture già esistenti o se necessita di un ulteriore trattamento di upgrading. Infine, si riporta anche il dosaggio di acido e base richiesto per mantenere il pH di digestione controllato, garantendo l’attività dei microorganismi.
Metanogenesi idrogenotrofa in-situ: modellazione di scenari tramite modello ADM1
Tiraboschi, Alessia
2023/2024
Abstract
In the context of decarbonization and the growing need to reduce energy imports, biomethane represents a fundamental substitute for fossil fuels, so much so that, recently, new research projects have been launched to grow the European biomethane industry (CORDIS Projects Info Pack) and the RepowerEU plan has launched the challenge of producing 35 bcm (billion cubic meters, Billion Cubic Meters) of biomethane by 2030 within the Union (EBA, 2024). The aim of this thesis is to simulate, through the ADM1 model, in-situ hydrogenotrophic methanogenesis, by injecting green hydrogen (H2) into the anaerobic digestion (AD) reactor. To this end, the potential of various substrates in producing biomethane is investigated and the trend over time of the output variables is studied as the H2:CO2 ratio introduced varies. First, the model results are compared with those obtained from the laboratory activity carried out in Viola Corbellini's doctoral thesis (Corbellini, 2019). Subsequently, substrates are studied whose fractionation into carbohydrates, proteins and lipids has been theoretically hypothesized, in order to simulate different influencing factors in composition. Modifications to the equations and parameters, inserted in the original ADM1, have been made in order to build a model capable of returning trends over time that are as representative as possible of reality. Thanks to the equations that describe the biological process, as far as allowed, it is possible to predict with greater accuracy any inhibitions of the biomass, allowing to meet the needs of digestion in the real field. The advantage of being able to simulate the process, even before its application, is in fact to evaluate its stability, performance and the costs associated with its maintenance. Furthermore, the maximum volumetric percentage of hydrogen allowed in gas transport and distribution networks in various countries is examined. With reference to current regulations, it is possible to understand whether the biomethane produced can be directly injected into existing infrastructures or whether it requires further upgrading treatment. Finally, the dosage of acid and base required to maintain the controlled digestion pH, guaranteeing the activity of microorganisms, is also reported.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/235172