Assessment of CO2 desorption from 13X zeolite for a prospective TSA process

• Published in: Adsorption : journal of the International Adsorption Society 2020-07, Vol.26 (5), p.813-824
• Main Authors: Morales-Ospino, Rafael, Santiago, Rafaelle Gomes, Siqueira, Rafael Magalhães, de Azevedo, Diana Cristina Silva, Bastos-Neto, Moises
• Format: Article
• Language: English
• Subjects: Adsorption; Carbon dioxide; Carbon sequestration; Chemistry; Chemistry and Materials Science; Computer simulation; Configuration management; Desorption; Engineering Sciences; Engineering Thermodynamics; Fixed beds; Flue gas; Gas recovery; Gas streams; Heat and Mass Transfer; Heating; Industrial Chemistry/Chemical Engineering; Purging; Regeneration; Selectivity; Surfaces and Interfaces; Thin Films; Zeolites
• ISSN: 0929-5607; 1572-8757
• DOI: 10.1007/s10450-019-00192-5

In this study, two configurations of Temperature Swing Adsorption (TSA) were assessed with the aim of evaluating their efficacy on CO 2 capture on commercial adsorbent zeolite 13X within a post-combustion scenario. A fixed bed setup was employed to measure breakthrough curves from the adsorption and desorption steps. Considering a dry desulfurized flue gas stream, breakthrough curves for CO 2 –N 2 (15/75 % v/v) in Helium were performed at 25, 50 and 75 °C. The desorption step was carried out following two TSA regeneration strategies: a two-step desorption arrangement ( configuration 1 ) consisting of a purging phase followed by a heating-purging phase, and a one-step desorption arrangement ( configuration 2 ) involving only the heating-purging phase. Adsorption equilibrium isotherms were also obtained for pure CO 2 (25, 50, 75, 100 and 125 °C) and N 2 (25, 50 and 75 °C) on zeolite 13X in the range of 0–1 bar. Finally, a mathematical model considering mass and energy differential balances was used to predict the whole adsorption-desorption history. The results obtained on breakthrough curves showed that CO 2 separation from N 2 on zeolite 13X is accomplished by adsorption under the studied conditions with a marked selectivity for CO 2 . In regards to the desorption phase, configuration 1 may not be adequate for an integration of adsorption-desorption steps once only the purge phase duplicates the desorption time as compared to the adsorption stage. On the other hand, configuration 2 is more 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 CO 2 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 feasible to be used for configuration 2 regeneration strategy so as to avoid energy penalties. Simulations were able to reproduce well the experimental breakthrough curves, even though some discrepancies were observed in the desorption histories.