High-sulfur capacity and regenerable Zn-based sorbents derived from layered double hydroxide for hot coal gas desulfurization

Mengmeng Wu; Bingwei Chang; Teik-Thye Lim; Wen-Da Oh; Junxi Lei; Jie Mi

doi:10.1016/j.jhazmat.2018.08.015

High-sulfur capacity and regenerable Zn-based sorbents derived from layered double hydroxide for hot coal gas desulfurization

J Hazard Mater. 2018 Oct 15:360:391-401. doi: 10.1016/j.jhazmat.2018.08.015. Epub 2018 Aug 6.

Authors

Mengmeng Wu¹, Bingwei Chang², Teik-Thye Lim³, Wen-Da Oh⁴, Junxi Lei⁵, Jie Mi⁶

Affiliations

¹ Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China; Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore. Electronic address: wumengmeng111@126.com.
² Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
³ Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
⁴ Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore; School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia.
⁵ Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore.
⁶ Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China. Electronic address: mijie111@163.com.

PMID: 30130697
DOI: 10.1016/j.jhazmat.2018.08.015

Abstract

The Zn-Al mixed metal oxide (ZnAl-MMO) with a plate-like structure was derived from Zn-Al layered double hydroxide. The ZnAl-MMO with a Zn/Al molar ratio of 3:1 exhibits superior absorption ability for H₂S in a simulated coal gas at 600 ℃ due to the special structure of the ZnAl-MMO. Besides ZnS, elemental sulfur is also produced during the desulfurization process. The deactivation model could well simulate the absorption behavior of H₂S. The sulfidation reaction over the sorbent shows large initial reaction rate constants (1110-5390 m³ min^-1 kg^-1) and low activation energy (29.5 kJ mol^-1). The regeneration rate of the used sorbent can reach 99.8% under the optimum conditions. The regenerated sorbents still show high sulfur capacity (ca. 30%), implying its great application potential for industrial-scale desulfurization of the hot coal gas.

Keywords: H(2)S; ZnO; desulfurization; layered double hydroxide; sorbents.