Fluidized Beds with Internals: A Real-Time Magnetic Resonance Imaging Study of Gas Bubbles and Particle Motion

Fluidized beds are frequently equipped with internals in order to modify the fluidization dynamics within the bed, such as reducing the size of gas bubbles, or enforcing specific particle circulation patterns[1,2]. Traditionally, the design of internals is often based on rules of thumb and empirical correlations derived from optical measurements in pseudo two-dimensional (2D) systems, or by inserting probes into 3D systems. However, such measurements are either influenced by wall effects (pseudo 2D systems) or do interfere with the particle flow (intrusive probe measurements). More recently, sophisticated tomographic techniques have been applied to study fluidization dynamics in freely bubbling fluidized beds, such as X-ray tomography[3], electrical capacitance tomography[4] and magnetic resonance imaging (MRI)[5–7]. In order to design and scale-up fluidized bed reactors with internals reliably and efficiently, we need fundamental insight into fluidization dynamics in large, 3D systems with internals.