Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification
Journal article, 2022

Chemical looping gasification (CLG) is an emerging process that aims to produce valuable chemical feedstocks. The key operational requirement of CLG is to limit the oxygen transfer from the air reactor (AR) to the fuel reactor (FR). This can be accomplished by partially oxidizing the oxygen carrier in the AR, which may lead to a higher reduction degree of the oxygen carrier under the fuel conversion. A highly reduced oxygen carrier may experience multiple issues, such as agglomeration and defluidization. Given such an interest, this study examined how the variation of the mass conversion degree of ilmenite may affect the conversion of pine forest residue char in a fluidized bed batch reactor. Ilmenite was pre-reduced using diluted CO and then underwent the char conversion at 850, 900, 950, and 975 degrees C. Our investigations showed that the activation energy of the char conversion was between 194 and 256 kJ/mol, depending upon the mass conversion degree of ilmenite. Furthermore, the hydrogen partial pressure in the particle bed increased as the oxygen carrier mass conversion degree decreased, which was accompanied by a lower reaction rate and a higher reduction potential. Such a hydrogen inhibition effect was confirmed in the experiments; therefore, the change in the mass conversion degree indirectly affected the char conversion. Langmuir-Hinshelwood mechanism models used to evaluate the char conversion were validated. On the basis of the physical observation and characterizations, the use of ilmenite in CLG with biomass char as fuel will likely not suffer from major agglomeration or fluidization issues.

Author

Victor Purnomo

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Daofeng Mei

Chalmers, Space, Earth and Environment, Energy Technology

Amir H Soleimani Salim

Chalmers, Space, Earth and Environment, Energy Technology

Tobias Mattisson

Chalmers, Space, Earth and Environment, Energy Technology

Henrik Leion

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Energy & Fuels

0887-0624 (ISSN) 1520-5029 (eISSN)

Vol. 36 17 9768-9779

Chemical Looping gAsification foR sustainAble production of biofuels (CLARA))

European Commission (EC) (EC/H2020/817841), 2018-11-01 -- 2022-10-31.

Driving Forces

Sustainable development

Areas of Advance

Energy

Subject Categories

Chemical Process Engineering

Bioenergy

Infrastructure

Chalmers Materials Analysis Laboratory

DOI

10.1021/acs.energyfuels.2c00944

More information

Latest update

4/11/2023