A comprehensive numerical investigation on the hydrodynamics and erosion characteristics in a pressurized fluidized bed with dense immersed tube bundles

• Fluidized bed with staggered tubes under elevated pressure is simulated using CFD-DEM method.
• Effects of operating pressure on solid characteristics averaged over time are analyzed.
• Mechanism of bubble induced particles impact on tubes is elucidated.

Based on the coupling method of computational fluid dynamics (CFD) with discrete element method (DEM), numerical investigation on the gas-solid hydrodynamics and erosion characteristics is conducted in a 3-D pressurized fluidized bed with immersed tube bundles. The effects of operating pressure on time-averaged solid-phase characteristics, solid circulation features, granular temperature and tube erosion patterns are analyzed. Elevated pressure accelerates both upward and downward particle flows, resulting in a lower solid concentration in the bottom part compared to the upper part. A theory is proposed to explain the occurrence of large solid velocity fluctuation. The distinct erosion distribution of each tube is found to be strongly related to solid flux distribution. The mechanism of bubble-induced tube erosion is represented and validated by simulation result.