Research Of Structure Design And Optimization For Discharger At Up-flow Oxygen Bleaching Tower

Nowadays energy saving and emission reduction is one of the most important topic in economy and society development. Cleaner production technologies in pulp bleaching like ECF & TCF become popular and in which oxygen delignification is used as an initial and important section. With the trend of increasing capacity, the properties of discharging equipment should be enhanced. However, the core technologies of discharger for oxygen delignification tower are mainly in charged by foreign enterprise and kept confidential, and there’s few national related research in this field. National facilities import dischargers but find problems in installation and operation.This paper analyzed the mechanism and properties of mid-consistency pulp under the condition of oxygen delignification, and found that it has poor fluidity with a high viscosity via experiments and theoretical summary. The mid-consistency pulp rose in the form of “plug flow” in the tube and became fluidization under the effect of enough shearing force.Base on the mechanism above, the outline shape, radius, length of rotor of rotational discharger with deduced and designed. The flow field of oxygen delignification tower and the partly flow field near the rotor was simulated by CFD. According to the results of simulation, effects of discharger with discussed, including effects on axial velocity distribution and fluidization. What’s more, the parameters of rotor with optimized.The testing system for the properties of discharger was designed and built. Experiments with mid-consistency bagasse pulp as fluid and dyed pulp as tracing particles were conducted. The flow trend in the tower was deduced according to the pouring time of tracing particles, and the performance of discharged with evaluated.CFD simulation related to the testing system with conducted. There was relevance between testing and simulation data, which verified the validity of CFD simulation.