The present work evaluates the hydrogen generation using the steam reforming system developed on Aspen HYSYS by Wood (former Amec Foster Wheeler). Hydrogen does not emit CO2 during its combustion and can be produced in multiple ways, making it a versatile molecule. “Green Hydrogen” is produced when the hydrogen generation source is renewable like wind/solar power or green feedstocks. In this study, the green feedstocks considered are glycerol (a by-product of biodiesel production), non-edible oils, lignocellulosic and algae biomass. To date, research based on the glycerol conversion to hydrogen was just limited to laboratory scale but in this work a full industrial process chain is developed from crude glycerol to hydrogen gas, implementing production and economical methodologies in line with large scale production of hydrogen. The fuel requirement for the steam reformer is completely satisfied by the tail-gas separated in the pressure swing adsorption unit, thus removing the necessity of natural gas as a fuel. Further performance evaluation shows that glycerol steam reforming is more efficient than the steam methane reforming process if the high-pressure steam is recovered as a product for the end-user. Assuming a target internal rate of return of 10% and a hydrogen production capacity of 10000 Nm3/h, the levelized hydrogen production cost obtained is 2.33 euro/kg. This production cost is compared with other hydrogen generation technologies and it is found to be close to that of natural gas generated hydrogen. Additional attention is dedicated to an optimization of the feedstock composition. It is evident that conserving methanol (5-30%) in the total glycerol feedstock promotes less overall feedstock consumption and more steam production for the same amount of generated hydrogen, leading to an increase of the total profit. A detailed sensitivity analysis is performed to prove this point. Based on the available research works, a process stream is theorized for non-edible oils and biomass feedstocks, the pre-treatment of which includes thermal cracking, visbreaking, hydrothermal liquefaction, and fast pyrolysis. The model compounds derived from the pre-treatment of these feedstocks have the theoretical potential to generate hydrogen via steam reforming if proper research and development are allocated to it.
Il presente lavoro indaga la generazione di idrogeno tramite un sistema di steam reforming sviluppato su Aspen HYSYS da Wood (ex Amec Foster Wheeler). L’idrogeno non emette CO2 durante la sua combustione e può essere prodotto in numerosi modi, essendo perciò una molecola versatile. L’"idrogeno verde" viene prodotto quando la fonte di generazione dell’idrogeno è rinnovabile, ad esempio da energia eolica, solare o da materie prime verdi. In questo studio, le materie prime verdi considerate sono glicerolo (un sottoprodotto della produzione di biodiesel), oli non commestibili, biomassa lignocellulosica e alghe. Fino ad oggi, la ricerca sulla conversione del glicerolo in idrogeno era solo limitata alla scala di laboratorio, ma nel presente lavoro viene sviluppata una catena di processi industriali completa dal glicerolo grezzo all’idrogeno, impiegando metodologie economiche e di produzione in linea con la generazione su larga scala di idrogeno. Il fabbisogno di carburante per il reformer a vapore è completamente soddisfatto dal gas di coda separato nell’unità PSA (Pressure Swing Adsorption), eliminando la necessità dell’integrazione di gas naturale. Un’ulteriore valutazione delle prestazioni dimostra che lo steam reforming di glicerolo è più efficiente del processo di reforming da metano se il vapore ad alta pressione viene recuperato come prodotto per l’utente finale. Supponendo un tasso interno di rendimento target del 10% e una capacità di produzione di idrogeno di 10000 Nm3/h, il costo livellato ottenuto per la produzione di idrogeno è di 2,33 euro/kg. Tale costo di produzione è confrontato con quello di altre tecnologie per la generazione di idrogeno ed è risultato essere vicino a quello dell’idrogeno generato da gas naturale. Un’ulteriore attenzione è dedicata all’ottimizzazione della composizione delle materie prime in input. È evidente che mantenere una percentuale di metanolo del 5-30% del flusso in input promuove un minor consumo complessivo di materie prime e una maggiore produzione di vapore a parità di idrogeno generato, portando ad un aumento del profitto totale. Un’analisi di sensibilità dettagliata viene eseguita per dimostrare questo punto. Partendo dalle ricerche disponibili, un flusso di processo è teorizzato per l’impiego di oli non commestibili e biomassa, il cui pretrattamento include cracking termico, visbreaking, liquefazione idrotermica e pirolisi rapida. I composti modello derivati dal pretrattamento di queste materie prime sono potenzialmente impiegabili nella generazione di idrogeno tramite steam reforming se supportati in futuro da adeguati sforzi di ricerca e sviluppo.
Techno-economic analysis of green hydrogen production from steam reforming of glycerol
Parsana, Shashwat
2019/2020
Abstract
The present work evaluates the hydrogen generation using the steam reforming system developed on Aspen HYSYS by Wood (former Amec Foster Wheeler). Hydrogen does not emit CO2 during its combustion and can be produced in multiple ways, making it a versatile molecule. “Green Hydrogen” is produced when the hydrogen generation source is renewable like wind/solar power or green feedstocks. In this study, the green feedstocks considered are glycerol (a by-product of biodiesel production), non-edible oils, lignocellulosic and algae biomass. To date, research based on the glycerol conversion to hydrogen was just limited to laboratory scale but in this work a full industrial process chain is developed from crude glycerol to hydrogen gas, implementing production and economical methodologies in line with large scale production of hydrogen. The fuel requirement for the steam reformer is completely satisfied by the tail-gas separated in the pressure swing adsorption unit, thus removing the necessity of natural gas as a fuel. Further performance evaluation shows that glycerol steam reforming is more efficient than the steam methane reforming process if the high-pressure steam is recovered as a product for the end-user. Assuming a target internal rate of return of 10% and a hydrogen production capacity of 10000 Nm3/h, the levelized hydrogen production cost obtained is 2.33 euro/kg. This production cost is compared with other hydrogen generation technologies and it is found to be close to that of natural gas generated hydrogen. Additional attention is dedicated to an optimization of the feedstock composition. It is evident that conserving methanol (5-30%) in the total glycerol feedstock promotes less overall feedstock consumption and more steam production for the same amount of generated hydrogen, leading to an increase of the total profit. A detailed sensitivity analysis is performed to prove this point. Based on the available research works, a process stream is theorized for non-edible oils and biomass feedstocks, the pre-treatment of which includes thermal cracking, visbreaking, hydrothermal liquefaction, and fast pyrolysis. The model compounds derived from the pre-treatment of these feedstocks have the theoretical potential to generate hydrogen via steam reforming if proper research and development are allocated to it.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/165651