(254b) Relationship between the net electrostatic charge inside a fluidized bed and particles accumulation on the column wall

Solids contact charging, known as triboelectrification, could occur in any gas-solid system during solids handling, transport, and processing. However, the extent of charging varies from one system to another depending the operating conditions as well as materials involved. Gas-solid fluidized beds in particular create an ideal environment for triboelectrification to occur because of the continuous collisions among the fluidizing particles and the column wall. Depending on the level of charge generation, operational challenges could arise including particle agglomeration causing deviation from the desired particle properties, accumulation of charged particles on the column wall requiring shutdowns for clean-ups, and electrostatic discharge resulting in a hazardous environment. Hence, much research has been carried out to better understand this electrostatics occurrence and its modeling in fluidized beds [1, 2]. Our latest experimental results show that there is a direct proportionality between the net electrostatic charge of the bulk of the bed particles and the number of particles sticking to the fluidization column wall [3]. Thus, diminishing this net charge will reduce the formation and progression of the column wall fouling. This finding will help in determining means to prevent or reduce fluidizing particle adhesion to the column wall with either manipulation of the fluidization operating conditions or addition of any materials that could counterbalance the existing net charge within the bed.

[1] Mehrani P., Murtomaa M., Lacks D.J., An Overview of advances in understanding electrostatic charge buildup in gas-solid fluidized beds, Journal of Electrostatics, 87, 64-78, 2017.

[2] Chowdhury, F., Ray, M., Sowinski, A., Mehrani, P., Passalacqua, A., A review on the modeling of electrostatic charging in gas-solid flows, Powder Technology, 389, 104-118, 2021.

[3] Taghavivand, M., Mehrani, P., Sowinski, A. Triboelectric effects of continuity additives and a silica catalyst support on polyethylene fluidized bed wall fouling, Chemical Engineering Science, 245, 2021.