A numerical modelling study of SO 2 adsorption on activated carbons with new rate equations

Ziyi Li, Yingshu Liu, Haihong Wang, Chuen-Tinn Tsai, Xiong Yang*, Yi Xing, Chuanzhao Zhang, Penny Xiao, Paul A. Webley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Modelling dynamic adsorption of sulfur dioxide (SO 2 ) on activated carbons (ACs) is significant in guiding practical desulphurization processes and making highly efficient use of adsorbents in terms of the adsorption rate which largely depends on particle size. In this work, models derived from the Vermeulen and an improved linear driving force (LDF) rate equation were studied for the first time on SO 2 adsorption over AC particles with different sizes. For larger particles (≥3 mm), breakthrough curves predicted by the Vermeulen equation showed good agreement with experimental data, demonstrating that intraparticle diffusion resistance varied with particle size, feed concentration, adsorption time and location. For smaller particles (1 mm), a correction on the volume-averaged adsorption capacity as a function of adsorption time and saturation in the rate equation was developed to avoid the underestimation of adsorption rate due to the inappropriate parabolic concentration profile inherent in the conventional LDF model. By providing a concentration gradient and adsorption rate closer to actual values, the improved LDF equation was confirmed to provide excellent prediction results on 1-mm particles. Different modelling characteristics of the two models indicates varying effects of intraparticle diffusion on adsorption rate with particle size regarding the specificity of SO 2 physisorption on ACs.

Original languageEnglish
Pages (from-to)858-866
Number of pages9
JournalChemical Engineering Journal
Volume353
DOIs
StatePublished - 1 Dec 2018

Keywords

  • Activated carbons
  • Adsorption
  • Breakthrough curve modelling
  • Intraparticle diffusion
  • Sulfur dioxide

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