| Biomass as a clean energy is widely used when environmental pollution becomesheavier and heavier. Among the many biomass utilization technologies, dual fluidizedbed gasification technology is the most superior, but the type of gas distributor has asignificant influence on circulation of bed material in a dual fluidized bed gasificationsystem. A cold dual circulation fluidized bed gasification system was build, and a conicalgas distributor was used in the gasification chamber, and effects of gas velocity to thegasification chamber and the riser, material weight, particle size and angle of the conicaldistributor on solids circulation rate was systematically researched, and the result wascompared with that under a planar distributor. The results indicate that solids circulationrate increases with increasing gas velocity in the two beds, but growth trends becomesflat gradually. With the rise of material weight and particle size, solids circulation rateincreases and decreases respectively. In addition, the bigger the conical distribor angle,the higher the solids circulation rate. By comparision, results show that solids circulationrate in a conical distributor is higher than that in a planar distributor. Because the conicalgas distributor can make uneven air distribution and enhance paricles mixing momention,which can improve material fluidization effectively and increase solids circulation rate.Based on work principle of the test bench and pressure balance of the system, adynamic prediction model was built, and the relative error between forcasting value andexperimental value was within±20%; using Matlab, the paper established3improved BPneutral network prediction models, and the best model was found by comparision. Thebiggest relative error is7.7035%and the mean error is3.5943%, with the lesser totalerror deviation and can better predict the solids circulation rate. It can provide certainguidance for actual industrial production. |
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