Experimental investigation of fluidized bed chemical looping combustion of Victorian brown coal using hematite

• Chemical looping combustion of Victorian brown coal is investigated.
• Fluidized bed reactor is used for CLC using hematite.
• Operating conditions are optimized for further scale-up considerations.
• Structural analyses of hematite particles are also reported.

An experimental investigation on chemical looping combustion (CLC) of Victorian brown coal is carried out in a fluidized bed of hematite. The aim of this study is to understand the feasibility of Victorian brown coal CLC as very little technical information is currently available on the process using these coals. The in situ CLC experiments are first performed using a thermogravimetric analyzer (TGA). The TGA results show good performance of hematite as oxygen carrier over five multiple re-dox cycles under CO2 gasification environment. Therefore, further investigation is performed using a bench-scale fluidized bed that operates in a batch mode cyclically with reduction in CO2 environment, and oxidation in air. Several tests have been conducted to assess the impact of different temperatures, particle size of hematite and CO2 concentration in a flowing fluidizing gas medium. It is observed that the hematite particles of 100–150 μm performed best with respect to carbon conversions that show an increasing trend with increasing temperature and CO2 concentration in the fluidizing gas.