Industrial & Engineering Chemistry Research, Vol.59, No.18, 8688-8703, 2020
Solid Holdup and Circulating Velocity in a Novel Airlift High-Speed Loop Reactor for the Methanol to Olefin Reaction
Based on the reaction characteristics of methanol to olefins, a novel high-speed loop reactor (HSLR) is proposed. Distinct hydrodynamics are anticipated to optimize the olefin yield and selectivity. The HSLR mainly comprises a fluidized bed and a draft tube. There are two main regions, i.e., the draft tube and annulus region. The draft tube region is a turbulent/fast fluidized bed where the solids in the reactor flow upward, while the annulus region is a bubbling/turbulent bed where the solids move downward. The solid holdup in the two regions and internal solid circulating velocity is investigated systematically. After dimensionless analysis and continuity of solid flow, calculation models for overall solid holdup in the two regions are established. The ratio of solid circulating flow in the lower loop section ranges from 0.769 to 0.965. In addition, a mathematical model for the internal solid circulating velocity is achieved on the basis of energy equilibrium, and energy dissipation rates are analyzed accordingly.