Study on the influence of baffle height and angle on the performance of coarse powder separator in power plant based on CFD-DPM method

Abstract

In this study, the two-phase motion characteristics in a coarse powder separator were investigated using computational fluid dynamics (CFD) method, discrete particle model (DPM) and isokinetic sampling experimental method, and the structure of the coarse powder separator was optimized to improve the efficiency of the separator. The results showed that the particle separation in different separation zones was also dominated by gravity separation and centrifugal separation, respectively. When the baffle angle was increased from 20° to 60° at a low mounting height, the tangential velocity in the separation zone was reduced by 67 % and the axial velocity was increased by 33 %. The effects of the baffle angle on the tangential and axial velocities were weakened with the rise of the baffles mounting height. The optimum operating condition of the chosen powder separator involved a baffle angle α 30°, a baffle height H = 6.27 m, and a inlet velocity v = 19.3 m/s. The fineness of coal powder at the fine powder outlet was reduced by 60 % and the fineness of coal powder at the coarse powder return port was improved by 43 % for the optimized model compared with the original coarse powder separator.