Experimental Study Of Flow Characters Of The High-density Circulating Fluidized Bed

A technology of clean coal has become a development trend, because of the energy structure and the problems of environmental in China. At present, high-density circulating fluidized bed coal gasification used in IGCC was consi-dered to be one of the most potential gasification, which can deal with coal of high ash, high sulfur, high ash melting point. It is the key of high-density circulating fluidized bed that how to establish the operating conditions of a high gas velocity and dense solid flux. To develop the high-density circulating fluidized bed coal gasification, it is necessary to know well the pattern of gas-solids flow and to get a good command of the law of gas-solids flow. The cold experiment rig of high-density circulating fluidized bed was designed and assembled (Φ0.205×7). Based on the LabVIEW8.5, the measurement control system of high-density circulating fluidized bed was designed, which can display and record the experiment parameter, including temperature, pressure, differential pressure and air flow.A series research was carried out, which includes the influence of solid concentration with operating parameters (solid flux, superficial velocity) and the structure of outlet of the riser; and the performance of U valve. The solid material is silica sand.Main achievements of the thesis are:(1) The experiment rig of high-density circulating fluidized bed was assembled which is of function of data acquisition and several different outlets It supports the thesis and the following research work.(2) The axial solid concentration become more obviously with increasing the solid flux and decreasing the superficial velocity.(3) The solid concentration is exponential type because of diversion effect using C outlet (smooth). When the solid flux is200kg/m2s, the height of solid concentration over0.1is about3m.(4) The solid concentration in the bed with outlet of T and L is C type, and the phenomenon of region increase of solid concentration appear on the2meters away from the center line of the outlet, and T type is more obviously than L type’s.(5) The solid flux of U valve is a linear relationship with the air flow of U valve. Relations of solid flux are different with different air flow.