The gas distributor (also called a grid) in a fluidized bed reactor is intended to induce a uniform and stable fluidization across the entire bed
cross-section, operate for long periods (years) without plugging or breaking, minimize weepage of solids into the plenum beneath the grid, minimize attrition of the bed material, and support the weight of the bed material during start-up and shut-down.
Eulerian granular multiphase model with a drag coefficient correction based on the energy-minimization multi-scale (EMMS) model was used to simulate a semi-industry scale circulating fluidized bed (CFB).
Particle attrition is usually a detriment to product quality and process cost. This paper discusses the development of a jet cup device that allows all of the sample particles to experience similar amounts of solids stresses.
Various types of internals have traditionally been used to improve fluidization quality. Some recent studies have shown that under some conditions there can be severe gas mal-distribution of gas in deep fluidized beds of Geldart group A materials.
Non-mechanical valves, especially the L-valves, have been used extensively in fluidized beds and circulating fluidized beds for solids recycling or to serve as a pressure seal. This paper presents a set of L-valve equations which relate the solids flow rate to the L-valve design, aeration rate, and pressure drop across the L-valve.
This paper reports the first quantitative comparison of magnetic resonance (MR) and electrical capacitance volume tomography (ECVT) on a 50 mm diameter gas-fluidized bed of silica−alumina catalyst support particles.
Snider, O’Rourke, and Zhao present a unified model for collisional exchange of mass, momentum, and energy between particles in gas/liquid/solid fluidized beds.
Commercial circulating fluidized bed (CFB) units require efficient operation of the riser and the solids return leg. The objective of this work was to study how horizontal baffles can be used to reduce or eliminate gas bypassing in deep beds.
Three cases are presented on the entrainment of various materials from fluidized beds in which agglomerated clumps of particles affected the measured entrainment rates. Evidence suggests that fine particles in many materials may be clumping together – resulting in a reduced entrainment rate.
Gas streaming is the severe bypassing of gas that can occur in deep, bubbling fluidized beds. Gas bypassing consists of a large jet that precesses around the walls of the fluidized bed. Details of possible mechanisms and possible techniques for detecting gas-bypassing are presented in this report.