Defluidization Study on Industrial Reactive Powders at High Temperature

Fluidized bed reactors are used in a wide range of industrial chemical processes and they are particularly useful in high temperature systems thanks to their ability to provide high heat transfer rates and rapid solids mixing, which lead to isothermal and more controllable conditions. Their applications spread the environmental, chemical, energy and process industries. For example, they are a key technology in the petroleum industry, catalytic chemicals synthesis processes, combustion and gasification of solid fuels, metals productions and many more.

Operations below incipient fluidizing conditions in combustion-type operations can lead to particle agglomeration and sintering which change the characteristics of the bed, leading to possible bed defluidization, unscheduled process downtime and additional costs. However, despite the countless researches that have been done so far, the details of the physical processes under such conditions are still not well understood, disclosing unrevealed features and challenging the researchers worldwide.

The objective of this work is to assess the effect of operative conditions, such as high temperature, air flowrate and particles size, on the flow properties and fluidization behaviour of multi-components systems of carbon coke and titanium ores. To this end, a simple approach for the early detection of aggregation and defluidization in the regime below and close to incipient fluidization - when the carbon combustion initiates the defluidization - is followed. The approach is based on the simultaneous measurements of local temperatures, the pressure drop across the particle bed. The mechanical and chemical characterization of the aggregated formed are performed offline and presented in details.