Carbon capture from gaseous streams is progressively gaining interest, especially due to global warming issues. The removal of CO2 is typically performed by absorption into Mono-ethanolamine (MEA) and Methyl-diethanolamine (MDEA) solutions, but the process is highly energy intensive since a lot of heat is required to regenerate the solvent. In this thesis work, two innovative solvents for the chemical absorption of CO2 have been investigated in detail: an aqueous solution of N,N-Dietylethanolamine (DEEA), a "green" amine that can be obtained from renewable sources (ethanol), and a mixture combining DEEA with the primary amine 3- (methylamino) propylamine (MAPA), which is able to demix into two heterogeneous liquid phases. A thermodynamic model for the description of the behaviour of the aforementioned solvents in carbon capture processes has been developed and implemented in Aspen Plus®, exploiting the experimental data available in the literature regarding physical properties, vapor-liquid (VLE) and liquid-liquid (LLE) of all the mixtures of interest, Henry's constants, chemical equilibrium and kinetics constants of the involved reactions and transport phenomena characterizing the system. Subsequently, in order to check its reliability, the model has been validated by checking its ability to reproduce VLE data of all the binary and ternary mixtures of interest. Once the model has been defined, a simplified natural gas sweetening plant for pipeline applications using the two solvents in question has been simulated in Aspen Plus® in order to carry out an initial evaluation of the performance of these solvents, especially in terms of energy requirements. DEEA seems to be a very promising solvent for future gas treatment applications: the removal of CO2 has been carried out effectively with reduced solvent flow rates and with consequent low energy consumption for regeneration. The DEEA - MAPA solvent has shown excellent performance in terms of absorption. However, the demixing of the solvent has not taken place to an appreciable extent, and the introduction of further unit operations has been necessary to favour this phenomenon. On the other hand, it has not been possible to evaluate the regeneration of this blend, mainly due to the lack of experimental data.
La cattura dell’anidride carbonica da correnti gassose è un processo che negli ultimi anni suscita un interesse sempre maggiore, specialmente a causa dei problemi legati al surriscaldamento globale. Tipicamente, la rimozione della CO2 avviene per lavaggio in soluzioni di Mono-etanolammina (MEA) e Metil-dietanolammina (MDEA), ma il processo richiede ingenti quantità di energia dato che per rigenerare il solvente occorre somministrare elevate quantità di calore. In questo lavoro di tesi sono stati investigati nel dettaglio due solventi innovativi per l’assorbimento chimico di CO2: un solvente acquoso di N,N-Dietil-etanolammina (DEEA), ammina “green” che può essere ottenuta da fonti rinnovabili (etanolo), e una miscela della stessa DEEA con l’ammina primaria 3-(Metilammino)propilammina (MAPA) a formare un solvente in grado di dare smiscelazione in due fasi liquide eterogenee. Un modello termodinamico per la descrizione del comportamento dei suddetti solventi nella cattura di CO2 è stato sviluppato e implementato in Aspen Plus®, a partire dai dati sperimentali disponibili in letteratura riguardo le proprietà fisiche, l’equilibrio liquido-vapore (VLE) e liquido-liquido (LLE) delle miscele di interesse, le costanti di Henry, le costanti di equilibrio e la cinetica delle reazioni coinvolte e i fenomeni di trasporto caratterizzanti il sistema. Successivamente, per verificare la sua affidabilità, il modello è stato verificato testando la sua capacità di riprodurre i dati di equilibrio VLE di tutte le miscele binarie e ternarie di interesse. Definito il modello, un processo semplificato di trattamento di gas naturale per applicazioni a rete domestica con i due solventi in esame è stato simulato in Aspen Plus®, al fine di effettuare una prima valutazione delle prestazioni dei solventi, soprattutto in termini di consumi energetici. La DEEA è risultata essere un solvente molto promettente per future applicazioni per il trattamento di correnti gassose: la rimozione di CO2 risulta effettuabile in maniera efficace con portate di solvente ridotte e con conseguente contenuto dispendio energetico per la rigenerazione. Il solvente DEEA – MAPA ha mostrato ottime prestazioni per quanto riguarda l’assorbimento. Tuttavia, la smiscelazione del solvente non è avvenuta in misura apprezzabile e l’introduzione di ulteriori operazioni unitarie è stata necessaria per favorirla. Non è stato invece possibile valutare la rigenerazione di questo solvente a causa della scarsità di dati sperimentali a disposizione.
Innovative solvents for carbon capture : diethylethanolamine (DEEA) and its blend with N-methyl-1,3-diaminopropane (MAPA)
GHILARDI, ALESSANDRO
2019/2020
Abstract
Carbon capture from gaseous streams is progressively gaining interest, especially due to global warming issues. The removal of CO2 is typically performed by absorption into Mono-ethanolamine (MEA) and Methyl-diethanolamine (MDEA) solutions, but the process is highly energy intensive since a lot of heat is required to regenerate the solvent. In this thesis work, two innovative solvents for the chemical absorption of CO2 have been investigated in detail: an aqueous solution of N,N-Dietylethanolamine (DEEA), a "green" amine that can be obtained from renewable sources (ethanol), and a mixture combining DEEA with the primary amine 3- (methylamino) propylamine (MAPA), which is able to demix into two heterogeneous liquid phases. A thermodynamic model for the description of the behaviour of the aforementioned solvents in carbon capture processes has been developed and implemented in Aspen Plus®, exploiting the experimental data available in the literature regarding physical properties, vapor-liquid (VLE) and liquid-liquid (LLE) of all the mixtures of interest, Henry's constants, chemical equilibrium and kinetics constants of the involved reactions and transport phenomena characterizing the system. Subsequently, in order to check its reliability, the model has been validated by checking its ability to reproduce VLE data of all the binary and ternary mixtures of interest. Once the model has been defined, a simplified natural gas sweetening plant for pipeline applications using the two solvents in question has been simulated in Aspen Plus® in order to carry out an initial evaluation of the performance of these solvents, especially in terms of energy requirements. DEEA seems to be a very promising solvent for future gas treatment applications: the removal of CO2 has been carried out effectively with reduced solvent flow rates and with consequent low energy consumption for regeneration. The DEEA - MAPA solvent has shown excellent performance in terms of absorption. However, the demixing of the solvent has not taken place to an appreciable extent, and the introduction of further unit operations has been necessary to favour this phenomenon. On the other hand, it has not been possible to evaluate the regeneration of this blend, mainly due to the lack of experimental data.| File | Dimensione | Formato | |
|---|---|---|---|
|
2020_12_Ghilardi.pdf
non accessibile
Descrizione: Tesi completa
Dimensione
6.01 MB
Formato
Adobe PDF
|
6.01 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/169265