Flow Characteristics In A High Flux/Density Circulating Fluidized Bed Riser

Now coal as the primary energy is China’s key energy. Combustion is the most way using coal, which resauts to pollution and low efficiency. Due to the growing pressure on energy and environmental protection, we are in need of developing clean and efficient power generation and coal conversion technologies. High-density circulating fluidized bed gasification technology overcomes the deficiencies of coal gasification technology, especally for low rank coal and low-quality coal which has huge reserves and low efficeiency. According to its lower cost and expediently maintenance, high-density circulating fluidized bed gasification technology is an important direction for the development of advanced gasification technology.Particals of group A are mainly researched in high-density circulating fluidized bed by researchers at home and abroad. Native researchers tested particals of group B in high-density circulating fluidized bed, and found that though the circulating flow rate is above 200 kg/(m2s), most of the solid concentration is lower than 0.1.This paper is based on high-flux/high-density circulating fluidized bed, using automatic density meter dynamic pressure detector and PV-5A partical measuring instrument. The research includes axial and radial solid concentrition distribution in riser,slip volicity and slip factor with resin and quartz.During the experiment resin achieved high-flux operating condition, while quartz achieved high-density operating condition. It is found that the axial particle concentration of both resin an4 "quartz are high in the bottom and low at the top regions. Axial particle concentration increases with circulating flow rate at a given superfical gas velocity and decreases with superfical gas velocity at a given circulaating flow rate. Radial solid holdups of both resin and quartz show that low in the center and high at the wall. As for resin, superfical gas velocity has a powerful influnce on radial concentrition in the central area, and has little impact at the wall, which is contrary to circulating flow rate. Particle concentrition distribution of quartz are seldom influnced by superfical gas velocity and circulating flow rate in the central area, which is contrary at the wall.There is some difference in slip properties between Geldart A and B, but their trends are basically the same. Particles of Geldart B with different size and density are very similar in slip properties.