To develop advanced flue gas desulphurization (FGD) technology in a circulating suspension bed (CSB), an experimental cold suspension bed facility with a cross section of 500mm X 500mm was built. The superficial air velocity in the bed can be varied up to 3.5m/s. Three geometrical configurations of the air jet entering the bed were designed and tested: (1) a single central circular pipe nozzle of 250mm ID; (2) four symmetrical circular pipe nozzles of 130mm ID each; and (3) a single central venturi nozzle. The gas-solid two-phase flow structures in the suspension bed were measured by a Particle Dynamic Analyzer (PDA) at different superficial velocities for each of the nozzle structures. Glass granules with diameters less then 100 micron were used as solid particles in the experiments. The granules with sizes less than 5 micron were good tracers of the gas phase. The solid particle concentration was controlled around 50 g/m~3 so that the PDA could be used. The experimental results show that a core region, a main flow region and a back-flow region in both the particle phase and the gas phase and that the particle phase and gas phase flow patterns are quite similar. A correlation is given to predict the particle velocity in the main flow region. The boundary between the main flow region and the back-flow region is correlated with the gas velocity and geometrical configurations. The particle turbulent intensity in the different regions of the suspension bed and the solid deposition on the bottom of the bed were also studied. This experimental study is of significance for the optimization of CSB-FGD reactor design in practice.
展开▼
