(45c)  Defluidization Behaviour of Industrial Reactive Powders at High Temperature

Macri', D., University College London
Lettieri, P., University College London - Torrington Place
Sutcliffe, S., Venator UK
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 (coal, wastes and biomass), metals productions and many more.

Operation below incipient fluidising conditions in combustion – type operations can lead to particle agglomeration and sintering which change the characteristics of the bed, leading to possible bed defluidisation unscheduled process downtime and additional costs. However, the details of the physical processes under such conditions are still not well understood. Despite the countless researches that have been done so far, such processes still disclose unrevealed features and challenge the researchers worldwide.

The objective of this work is to assess the effect of high temperature on the flow properties and fluidization behaviour of such systems using carbon coke and two different titanium ores. To this end, a simple approach for the early detection of agglomeration and defluidisation in the regime below incipient fluidization - when the carbon combustion initiates the defluidization- will be followed. Such an approach is based on the simultaneous measurements of local temperatures and the pressure drop across the particle bed.