Experimental investigation of CLC coal combustion with nickel based particles in a fluidized bed

An experimental study has been carried out on coal combustion in a fluidized bed of metal oxides. The aim of this study is to improve understanding of reaction mechanisms (devolatilization, gasification), in order to provide reliable data to model coal combustion with metal oxides as a function of operating conditions. This modelling will then be useful to scale up the process.The experimental set-up consists of a fluidized bed reactor of 50 mm internal diameter, filled with metal oxides and equipped with a batch coal injection device to inject a controlled amount of coal in the dense phase of the bed. The reactor is fluidized either with nitrogen to study the coal devolatilization step, or with nitrogen and water to study the reducing step during which coal is gasified. After each reduction, the solid is reoxidized with air.In the present study, nickel oxide particles were used as an oxygen carrier. Several tests have been conducted to study the impact of different operating parameters on coal combustion, such as temperature, steam concentration in fluidization flow, and coal particles size.

► We study coal combustion in a bed of NiO/NiAl2O4 fluidized by steam and nitrogen. ► Increasing temperature increases coal conversion rate. ► Increasing steam partial pressure increases coal conversion rate. ► Fuel oxide particles size does not have any significant impact on coal combustion.