气泡修正多尺度曳力模型的鼓泡流化床生物质气化分析

发布时间：2018-07-26 09:16

【摘要】：以双流体模型为框架,气泡修正多尺度曳力模型描述介观尺度作用影响,结合化学反应动力学方法建立生物质气化模型,模拟了鼓泡流化床内生物质气化过程。采用气泡修正多尺度曳力模型考虑了介观尺度影响,使气固异相反应增强,模拟结果更接近实验值。模拟结果给出了颗粒浓度、速度矢量瞬时分布、气体组分摩尔分数瞬时分布及碳和灰分的质量分数瞬时分布特性。分析了氧当量比对鼓泡流化床生物质气化过程的影响。总体上,气体产量随着氧当量比的增加而减小。经分析得出,H_2和CH_4的产量与氧当量比有着较高的相关性,拟合优度都在0.99以上;对于CO和CO_2,则用三次多项式拟合时能有较好拟合优度。并且,CO随着氧当量比的增加先下降较快,然后平缓,最后再次较快下降。而CO_2的下降趋势则与CO正好相反,先平缓,后下降快,最后再次平缓。
[Abstract]:Based on the two-fluid model, the bubble modified multi-scale drag model was used to describe the mesoscale effect, and the biomass gasification model was established based on the chemical reaction kinetics method, and the biomass gasification process in bubbling fluidized bed was simulated. The effect of mesoscopic scale is taken into account in the bubble modified multiscale drag model, which enhances the gas-solid heterogeneous reaction, and the simulation results are closer to the experimental value. The simulation results show the instantaneous distribution of particle concentration, velocity vector, molar fraction of gas component and the instantaneous distribution of mass fraction of carbon and ash. The effect of oxygen equivalent ratio on biomass gasification process in bubbling fluidized bed was analyzed. As a whole, the gas output decreases with the increase of oxygen equivalent ratio. The results show that there is a high correlation between the output of H2 and CH_4 and the oxygen equivalent ratio, the goodness of fit is above 0.99, and for CO and CO2, there is a better fit degree when the cubic polynomial is used to fit it. With the increase of oxygen equivalent ratio, CO decreases rapidly, then flattens, and then decreases again. However, the decreasing trend of CO_2 is opposite to that of CO.
【作者单位】：哈尔滨理工大学机械学院;哈尔滨第703研究所燃气轮机室;哈尔滨工业大学能源科学与工程学院;
【基金】：国家自然科学基金(51406045) 中国博士后自然科学基金(2016M590122) 哈尔滨理工大学青年拔尖创新人才培养计划(201504)项目
【分类号】：O359

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