The direct solid-solid reaction between coal char and iron-based oxygen carrier and its contribution to solid-fueled chemical looping combustion

Liangyong Chen, Jinhua Bao, Liang Kong, Megan Combs, Heather S. Nikolic, Zhen Fan, Kunlei Liu

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Chemical looping combustion (CLC) is an advanced technology developed to achieve highly efficient fuel combustion with in-situ CO2 capture. In this process, metal oxide particles are used as an oxygen carrier (OC) to transport lattice oxygen for fuel combustion. In this process, a stream of CO2 and steam is produced by successful separation of atmospheric N2 and the gaseous product of combustion. In CLC of solid fuel, metal oxide particles are physically mixed and react with solid fuel at high temperature using gasification enhancer, such as steam, or CO2. A full understanding of the reaction mechanism between the OC and solid fuel is vital for OC development and the fuel reactor design. Several reactions may be involved in solid-fueled CLC when an iron-based OC is used, including (1) solid fuel devolatilization/gasification, (2) OC reduction with intermediate syngas, (3) the solid-solid reaction between OC and solid fuel via direct contact, and (4) the homogeneous water-gas shift reaction. The former two reactions have been extensively studied in recent years. This study focuses on the third reaction, the solid-solid reaction, which occurs thermodynamically at typical operational temperatures of CLC. The direct solid-solid reaction between coal char and two iron-based OCs via random particle collision in a fluidization bed regime was investigated and focuses on the reaction kinetics and the carbon conversion at different temperature. The contribution of the solid-solid reaction to the global carbon conversion was estimated for steam-gasified CLC at different temperature. The solid-solid reaction via static contact in a thermal-gravimetric analyzer (TGA) was also tested to evaluate the role of different OCs and to better understand the reaction mechanism between the two solid particles.

Original languageEnglish
Pages (from-to)9-18
Number of pages10
JournalApplied Energy
Volume184
DOIs
StatePublished - Dec 15 2016

Bibliographical note

Publisher Copyright:
© 2016

Keywords

  • Chemical looping combustion
  • Direct solid-solid contact reaction
  • Iron-based oxygen carrier
  • Solid fuel

ASJC Scopus subject areas

  • Mechanical Engineering
  • General Energy
  • Management, Monitoring, Policy and Law
  • Building and Construction
  • Renewable Energy, Sustainability and the Environment

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