生物质快速热解流化床反应器气力进料特性

Pneumatic feeding characteristics of fluidized bed reactor for biomass fast pyrolysis

为探究不同工况下热解流化床反应器的气力进料特性,设计并搭建了流化床反应器气力进料冷态试验装置。生物质原料和床料分别采用落叶松颗粒和石英砂颗粒,通过试验测得了本装置的最小流化速度,研究了流化气速、喷动气速、流量比、初始静床高、石英砂粒径、落叶松粒径对流化床反应器气力进料特性的影响。试验结果表明:流化气速和喷动气速的增加均会提高进料率;流化气使床料流化并为落叶松颗粒提供进料空间,喷动气为落叶松颗粒提供动能,并平衡一部分床层压力;落叶松与石英砂粒径的增加对进料效果不利;流量比在1.9~2.7范围内进料率高且稳定性好。本文构建了生物质、床料与气体的三相流物理及数学模型,开展试验对模型进行验证,结果表明其预测误差为±13%。

In order to achieve a safe,continuous and stable supply of biomass feedstock to the fluidized bed pyrolysis reactor,a cold test apparatus for fluidized bed pneumatic feeding was designed and constructed.Larch and quartz sand were used as raw material and bed material respectively.The minimum fluidization velocity of the apparatus was measured and the effects of fluidized gas velocity,injection gas velocity,flow rate,initial static bed height,bed size and feedstock particle size on the feeding characteristics were studied.Experimental results showed that increasing the fluidized gas velocity and injection gas velocity could increase the feed rate.Fluidized gas provided feed space for biomass particles through fluidization of bed material.Injection gas provided kinetic energy for biomass particles and balanced part of the bed pressure.Increasing the particle size of biomass and bed material was detrimental to the feeding characteristics.Reasonable control of the gas flow ratio could improve the feeding rate and feeding stability.A three-phase flow model of biomass,bed material and gas was constructed to research the relative relationship between different parameters and feed rate.Experiments were carried out to verify the model.Results showed that the derivation error was±13%.