Spatiotemporal statistical characteristics of multiphase flow behaviors in fuel reactor for separated-gasification chemical looping combustion of solid fuel
Spatiotemporal statistical characteristics of multiphase flow behaviors in fuel reactor for separated-gasification chemical looping combustion of solid fuel
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DOI：
10.1016/j.cej.2021.128575
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发表时间：
2021-05
影响因子：
15.1
通讯作者：
Xudong Wang;Y. Shao;Baosheng Jin
中科院分区：
文献类型：
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作者：
Xudong Wang;Y. Shao;Baosheng Jin
分离气化化学链燃烧(SGCLC)对固体燃料具有很高的转化效率。SGCLC的燃料反应器(FR)被设计为气化炉(GR)和连续式还原反应器(RR)，其中包括气相、沙相和载氧相。为了更清楚地了解多相流的流动特性，设计了一台FR样机，并用计算流体力学(CFD)方法对FR内的气固两相流体力学进行了研究。通过改变气速和OC流量来研究它们对流动特性的影响。在基本条件下，当气体体积分数达到0.80时，气泡在GR中的概率从底部的0增加到0.33微米时的0.64。气固两相特性的时空统计结果表明，提高气速可以增强气固两相压力和气速分布的非均质性。当气速从1.8m/S加速到2.2m/S时，压力和气速标准差的平均值从13.71ppa增加到18.66cpa，从2.08亿m/S增加到2.55亿m/S，相反，对RR内压力分布的非均质性产生了相反的影响。将OC流量从0.6亿kg/S增加到0.800万kg/S，可以扩大RR中的OC库存，提高RR中压力分布的标准差。在1.85米处，RR值的平均压力标准偏差由3.12×10-6增加到4.82×10-6，气体-有机碳的混合和接触可以得到改善，以保证充分的燃烧反应。
Separated-gasification chemical looping combustion (SGCLC) has high conversion efficiency for solid fuels. Fuel reactor (FR) in SGCLC is designed as a gasifier (GR) and a connected reduction reactor (RR) with gas, sand and oxygen carrier (OC) phases. In order to clearly know the multiphase flow characteristics, a FR prototype is designed and the gas-solid hydrodynamics in FR are investigated using computational fluid dynamic (CFD) method. The gas velocity and OC flowrate are changed in simulations to study their effects on flow behaviors. Bubble probability in GR increases from 0 at bottom to 0.64 at 0.33 m while the gas volume fraction reaches 0.80 herein under fundamental condition. Spatiotemporal statistical results of the characteristics of gas and solid phases demonstrate that increasing gas velocity can enhance the heterogeneity of pressure and gas velocity distributions in GR. The mean values of pressure and gas velocity standard deviations increase from 13.71 Pa to 18.66 Pa and from 2.08 m/s to 2.55 m/s at 0.33 m when gas velocity accelerates from 1.8 m/s to 2.2 m/s. On the contrary, it has opposite effect on heterogeneity of pressure distribution in RR. Increasing OC flowrate from 0.6 kg/s to 0.8 kg/s can enlarge OC inventory in RR and enhance the standard deviation of pressure distribution in RR. The mean value of pressure standard deviations in RR increase from 3.12 Pa to 4.82 Pa at 1.85 m. The gas-OC mixing and contact can be improved for sufficient combustion reaction.