Experimental Study on Flow Behavior in a Gas‐Solid Fluidized Bed for the Methanol‐to‐Olefins Process

Abstract

A cold model experimental system is established to investigate the flow behavior in a gas-solid fluidized bed for the methanol-to-olefins process catalyzed by SAPO-34. The system comprises a gas distributor in a F 300 × 5000 mm acrylic column, double fiber optic probe system and a series of cyclones. The experiments are carried out under conditions of atmospheric pressure and room temperature with different superficial velocities (0.3930-0.7860 m s -1) and different initial bed heights (600-1200 mm). The effects of radial distance, axial distance, superficial gas velocity, and initial bed height on the solid concentration and particle velocity in the bed are discussed. The time-averaged solid concentration and rising particle velocity profiles under different conditions are obtained. The results show that an increase in the value of r/R or initial bed height results in an increase in the solid concentration but a decrease in the rising particle velocity in the dense phase area, while improvement of the superficial gas velocity has a negative influence on the solid concentration but results in an increase in the rising particle velocity.

Flow development and prediction of solids concentration in a large gas‐solids turbulent fluidized bed

“…The Sauter mean diameter of particles was measured using a MASTERSIZER 3000 analyzer. The local solids concentration in the dense region of the TFB could be reasonably assumed as symmetric, as confirmed by Wang et al [10] and Du et al [30] Accordingly, the local solids concentration was only measured in one radial direction.…”

“…Wang et al [10] 5 0.3 Sand 154$180 2550 0.6 0.5 0.39-0.59 □ Chaouki et al [47] -0.2 MgO 120 -0.5 0.15 0.4-0.65 4…”

“…The fluidized gas tends to pass through the centre of the column, because of the wall effect. [10] Moreover, it induces the particles to move upward, and bubble breakup leads to a considerable number of particles being propelled onto the wall. [9] Therefore, the ε s in the central region first decreases.…”

“…Turbulent fluidized beds (TFBs) are extensively employed in industrial processes, such as the production of maleic anhydride and acrylonitrile and Fischer-Tropsch synthesis, because they present the advantages of rapid mixing of particles and excellent mass and heat transfer rates. [1,2] Recently, studies on the hydrodynamic characteristics of TFB have been mainly focused on transition velocity, [3][4][5] gassolids mixing, [6,7] solids concentration, [8,9] particle velocity, [2,10] bubble behaviour, [11] and scale-up effects. [12,13] Solids concentration is a crucial parameter in the optimal design of fluidized reactors, because it significantly influences the gas-solids contact, mass and heat transfer rates, and reactor performance.…”

Statistical Optimization for Production of Light Olefins in a Fluidized‐Bed Reactor

“…On the other hand, fluidized beds have been used worldwide in many industrial applications [12,13]. Generally, one of the major advantages of studying MTO reaction in a fluidized bed is the spatial uniformity of the particulate phase.…”