The performance of the pilot scale atomizer is studied experimentally. Advanced techniques were applied to measure the size of slurry droplets with a high speed infrared camera followed by digitalization of a series pictures automatically. The effects of coal concentration in slurry, gas-to-slurry mass flow ratio on the average size of the droplets, represented by the Sauter mean diameter (SMD) of droplets were studied. The profiles of droplet size and the local flow rates in the axial and radial directions were measured to determine the development of the spray. The results show that atomization quality is improved by an increase in gas-to-slurry mass flow ratio and by a reduction in slurry flow rate. In the near nozzle region, the slurry flow rate concentrates in a narrow region in the centerline with large size of droplets. The average size of slurry droplets and local flow rates in centerline decrease as distance to the nozzle increases, due to secondary atomization of the large droplets. The large droplets in centerline are broken in to smaller droplets and spread in a wider region in the radial direction. At about 8 cm from the nozzle, local flow rates and the droplet size keep unchanged with a further increase of distance from the nozzle, with an average droplet size below 50 μm. The results provide information on design of atomizers and selection of operation conditions for gasification of CBS in an entrained flow reactor.
展开▼
