Li-LSX-zeolite evaluation for post-combustion CO2 capture

Rasmus Kodasma, Javier Fermoso, Aimaro Sanna

Research output: Contribution to journalArticle

12 Citations (Scopus)
51 Downloads (Pure)

Abstract

Lithium low silica X type (Li-LSX) zeolite is typically used for industrial N2/O2 separation processes, but its potential as a carbon dioxide capture sorbent has not been fully evaluated yet. In this work, Li-LSX zeolite was investigated as CO2 sorbent under post- combustion conditions in TGA and Fixed-bed configurations. The maximum adsorption capacity and CO2/N2 selectivity were determined to be 4.43 mmol g-1 and 85.7 at 60ºC and in presence of 14% CO2, using a packed bed configuration. The CO2 and N2 adsorption capacity was decreased of 10 mol% when the initial calcination temperature was raised from 60 to 300ºC due to a decreased micropore surface. However, the high calcination temperature increased the CO2 selectivity to 128.1 and increased the adsorption rates due to enhanced basicity (1 order of magnitude) and external surface (+75-80%) in the Li-LSX zeolite.
The sorption stability at 60ºC was found to be excellent during 85 sorption cycles over 35 hour period with Li-LSX showing negligible difference in adsorption capacity throughout the cycles and a working capacity of 2.45 mmolCO2/g after an initial calcination at 550°C (2 min) and cyclic adsorption at 60°C (6 min) and desorption at 420°C (5 min). The Avrami kinetic model shows the coexistence of different adsorption mechanisms. CO2 adsorption rate increased with the increasing CO2 partial pressure, as a result of the facilitated CO2 diffusion processes. Film diffusion was determined as the rate-limiting step for CO2 adsorption. Therefore, based on these findings, Li-LSX represents a promising sorbent for post-combustion carbon capture.
Original languageEnglish
Pages (from-to)1351-1362
Number of pages12
JournalChemical Engineering Journal
Volume358
Early online date9 Oct 2018
DOIs
Publication statusPublished - 15 Feb 2019

Keywords

  • Carbon capture and storage
  • CO solid adsorbent
  • Li-LSX-zeolite
  • Zeolite

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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