Study For The Minimum Spouting Velocity And Pressure Fluctuation Characters Of An Annual Spouted Bed Using Fine Particles

Since invented in 1950s for processing coarse particles, spouted bed technology has been applied initially to dryness of particles, then gradually expand to a wide field of chemical process which includes dryness, comminution, prilling, gasification, combustion, iron ore deoxidization, coke activation, petroleum thermal cracking etc. Although as a branch of fluidization technology, their flow mechanisms are quite different. The particles mixing in spouted bed is induced by a steady axial jet, which is more regular than complicated particles flow in fluidized bed.With the extension of spouted bed technology, many modified spouted beds have been designed by researchers. These modified spouted beds have been applied to various industrial institutions. Base on the deep research on spouted bed mechanism, a novel annular spouted bed with multi-nozzle has been proposed in this thesis, for combination of spouting and coal gasification. The statistic and power spectrum analysis methods are adopted to research the fluid dynamics and pressure fluctuation characters in that novel spouted bed. The study is expected to provide correct evidence for industrial application.Based on the angled and vertical nozzles spouted bed using fine particles, present research mainly consists of following sections: (â…°) research on the primary fluid dynamic parameters of spouted bed which include the minimum spouting velocity and the maximum pressure drop of bed layer. Through changing the operation parameters, including particles diameter, particles density, nozzles dimension, spouted bed diameter, static bed height, etc, got the experimental dates and calculated the nonlinear recursion. The error between experimental results and calculation results is less than 7%. (â…±) research on the origin of pressure fluctuation in spouted bed. By the method of statistics and power spectrum analysis, we considered there are three main sources for the pressure fluctuation in spouted bed, which consist of the impulse from air flow when it entering nozzles, the intermittent movement of air flow's vertical transmission, the annular interaction between jets from multiple nozzles. (â…²) research on the spouting characters of spouted bed with angled nozzles, contrast the particles mixing mechanism in vertical and angled flow.