Assessment of temperature swing adsorption configurations for CO2 capture on zeolite 13X

• Ano de defesa: 2018
• Autor(a) principal: Ospino, Rafael Augusto Morales
• Orientador(a): Bastos Neto, Moisés
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Engenharia química; Adsorção; Zeolitos; Zeolite 13X
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/31578

In this study, two configurations of Temperature Swing Adsorption (TSA) were assessed with the aim of evaluating their efficacy on CO2 capture on commercial adsorbent zeolite 13X within a post-combustion scenario. A Fixed Bed Laboratory Unit (FBU) with a single column was employed to obtain experimentally breakthrough curves (adsorption) and the subsequent depletion profiles (desorption). Considering a dry desulfurized flue gas stream, breakthrough curves for CO2-N2 (15/75 % v/v) in Helium were performed at 25, 50 and 75 °C. The desorption step was accomplished following two TSA regeneration strategies: a two phase desorption arrangement (configuration 1) consisting of a purging phase and then a heating-purging phase, and a one phase desorption arrangement (configuration 2) involving only the heating-purging phase. Adsorption equilibrium isotherms were also obtained for pure CO2 and N2 on zeolite 13X at the same temperatures of the dynamic tests in the range of 0-10 bar. Finally, a mathematical model formulation, considering isotherm modeling and transport phenomena balances, was performed to predict the whole adsorption-desorption profile. The results obtained on breakthrough curves showed that CO2 separation from N2 on zeolite 13X is accomplished by adsorption under the studied conditions with a meaningful preference on CO2. In regard with the desorption phase, configuration 1 may not be proper for an integration of adsorption-desorption steps once only the purge phase duplicates the time of the adsorption stage. On the other hand, configuration 2 is likely to synchronize the whole adsorption –desorption process since the regeneration time was significantly reduced by this strategy. However, configuration 1 managed to obtain full CO2 recovery with all the temperatures tested during the heating step, whereas configuration 2 reached recovery values around 92 %. Moderate temperatures (e.g. 125-150 °C) are encouraged to be used for configuration 2 regeneration strategy to avoid energy penalties. Simulations were able to reproduce well the experimental breakthrough curves, however for the desorption profiles, some discrepancies were observed.