Numerical simulation and optimization of gas-solid turbulence flow in a precalciner

摘要

To optimize the gas-solid flow field of an actual precalciner, numerical simulation was carried out using operational-based boundary conditions. In Euler coordinate system the gas phase is expressed with k-ε model, in Lagrange coordinate system the solid phase is expressed with Discrete Phase Model (DPM), and the random effects of turbulence on the particle dispersion is accounted for with Discrete Random Walk (DRW) model. The predicted gas velocity field shows that the gas flow rises up spirally, which agrees well with what observed on the actual running precalciner. The calculated raw meal concentration distributions are consistent with the actual conditions, showing a good dispersing condition. By changing the initial tertiary air velocity but fixing the initial flue gas velocity-and vice versa-the predicted results were compared. With the fixed initial flue gas velocity, the tertiary air velocity range between 25 m/s and 30 m/s is suggested. With the the fixed initial tertiary air velocity, it is optimum when the flue gas velocity is between 25 m/s and 35 m/s.