Study On Configuration Of Conical Fluidized Bed And Fluidization Characteristics Of Biomass

Because of foil energy increasingly exhaustion and the problem of environment, so allgovernments and scientists pay more attention to biomass resource which is abundant,renewable, and sustainable and are benefit to improve environment. Biomass energy is anexistent form of solar energy, biomass energy be saved in biomass through photosynthesis formaking light into chemistry energy. Their reasonable and high efficient utilization will beplaying a positive role for resolving the crisis of energy resources and the improving humanexistence environment.Fluidized technology has makes big progress, but until 1975, the technology was appliedto biomass gasification. Biomass fluidized is a hot point of research both in China and abroad.Extensive review was made on the development of the biomass fluidized technology, and aseries of studies on biomass cold fluidized bed were operated.In this thesis, the compositions of sawdust and rice hull were analyzed. From industryanalysis, the ash content of sawdust is 1.61％, but ash content of rice hull is 17.1％, and 60％ofash is Si, so extract Si from ash of rice hull is feasible, in the same time increase value-addedof rice hull; the volatile of sawdust more than rice hull and fixed carbon is rather adjacent. Theaverage diameter of sawdust was determined.This thesis secondly studied that in the conditions of different perforated rate ofdistributors, different particle size and the different bed height to fluidization velocity isdetermined in cold column fluidized bed. The results of this experiment are the effects ofperforated rate of distributor and the bed height on minimum fluidization velocity are rathersmall, and the effect of particle size on minimum fluidization is very obvious.Under different conical angle of fluidized bed, different conical distributor, differentperforated rate of distributor, the empty conical fluidized bed was studied. The conicaldistributor didn't changed, the conical angel of conical fluidized bed increase the effect onconical distributor increase also. The conical angel of-conical fluidized bed didn't changed, theperforated rate of distributor changed, and the curve of pressure to velocity didn't change. Theperforated rate of distributor is same, the conical angel changed, the curve of pressure tovelocity is same. In the experiment, with the bed height increase, the minimum fluidizationvelocity increase; and the particle size increase, minimum fluidization velocity is also increase;the conical angel of conical fluidized bed increase, the minimum fluidization velocity increase.In different conditions on fluidized state and stability of conical fluidized bed. The conlusions are: the conical angel of the conical fluidized bed is 20°, the fluidized state havesmall difference in conical distributor and distributor plate. The angle of conical bed increase,the fluidized state will have big difference. The angle is 60°and the conical as distributor, themass of fluidized is less, the most of material is the bottom of conical bed. The effect ofdistributor plate is much better than the conical distributor. Sawdust and rice hull can fluidize.The annular gap of conical distributor different, the angle of conical bed is same, the fluidizedquality of 10mm annular gap is better than the other conical distributors. The annular gap ismore wide, the conical bed have more slugging phenomenon and the pressure fluctuate is turnbig.In the experiment the flow of 2％and 4％distributor plates don't easy to control, becausethe pressure is very big and the pressure fluctuate of conical bed is too big. The fluidizedquality of 6％distributor is better than the other two distributor plates.It could cacluated the minmum flow velocity of cylindrical fluidized bed by theexperiment database. By these databases it can deduce the academic formula of minimum flowvelocity in cylindrical fluidized bed and conical fluidized bed.On the base of small scale conical fluidized bed, the big fluidized bed was studied. The first allit is the debugging of the big sclale conical fluidized bed. Feed-in system, fluidized andcirculate system were studied, some conclusion were concluded: the the academic equation ofconical distributor and cyclone were duced.