Hydrodynamic characteristics of a large-scale triple-bed combined circulating fluidized bed
Hydrodynamic characteristics of a large-scale triple-bed combined circulating fluidized bed
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DOI：
10.1016/j.powtec.2011.01.018
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发表时间：
2011-05
影响因子：
5.2
通讯作者：
C. Fushimi;G. Guan;Y. Nakamura;M. Ishizuka;A. Tsutsumi;S. Matsuda;H. Hatano;Yoshizo Suzuki
中科院分区：
文献类型：
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作者：
C. Fushimi;G. Guan;Y. Nakamura;M. Ishizuka;A. Tsutsumi;S. Matsuda;H. Hatano;Yoshizo Suzuki
建立了一种新型大型三床复合循环床(TBCFB)，它由提升管(高16.6m，内径0.10m)、下行管(高6.5m，内径0.10m)和鼓泡床(BFB；0.27×0.75×3.4m~3)组成，作为气化炉的冷态模型。新反应器设计的目的是实现煤/生物质(火用)回收水蒸气气化所需的高固体质量通量。在循环流化床中，在高炉和提升管底部之间安装了气密床(气密床，高5.0m，内径0.158m)，以增加压力头，将固体输送到提升管。在环境条件下，通过独立控制提升管、下降管、沸腾床和固定床的空气流量，改变床高，考察了石英砂颗粒(算术平均直径为12 8μm)的水动力行为。当提升管气速为0.10m/S时，固体质量通量(Gs：kg/(M2s))随提升管气速(UGr)的增大而显著增大。在UGR=12m/S，HGSB=4.6m时，最大吸水量为546 kg/(m~2·s)。这是因为随着GSB高度的增加，将固体输送到提升管底部的压力水头增加得足够多。根据表观压力差得到的固含率(εS)，发现在提升管底部(HR≤5m)形成了致密相(固含率：0.070-0.095)。下行床内的流动在1.5m处发展。当气速为406 kg/(m~2·s)时，随着气速从0.0212增加到1m/(S)，下降管发展区固含率由原来的0.33%下降到0.0128%。
A novel large-scale triple-bed combined circulating fluidized bed (TBCFB), consisting of a riser (16.6m in height, 0.10m inner diameter), a downer (6.5m in height, 0.10m inner diameter) and a bubbling fluidized bed (BFB; 0.27×0.75×3.4m3), was constructed as a cold model for a gasifier. The purpose of the new reactor design was to achieve a high solids mass flux which is required for exergy recuperative steam gasification of coal/biomass. In the TBCFB, a gas-sealing bed (GSB; 5.0m in height, 0.158m inner diameter) was installed between the BFB and the riser bottom to increase the pressure head to transport solids to the riser. The hydrodynamic behavior of silica sand particles (arithmetic mean diameter is 128μm) was investigated by independently controlling the flow rates of air in the riser, downer, BFB and GSB, and varying the bed heights of the BFB (HBFB) and GSB (HGSB) under ambient conditions. When the GSB gas velocity (Ugg) was 0.10m/s, the solids mass flux (Gs: kg/(m2s)) substantially increased with increase in riser gas velocity (Ugr). The maximum Gsobtained was 546kg/(m2s) at Ugr=12m/s and HGSB=4.6m. This is due to the fact that the pressure head for transport of solids to the riser bottom increased sufficiently by increase in the GSB height. From the solids holdup (εs) obtained from the apparent pressure difference, a dense phase (solids holdups: 0.070–0.095) was found to be formed at the bottom part of the riser (Hr≤5m). The flow in the downer was developed in 1.5m. The solids holdup in the developed area of the downer decreased from 0.0212 to 0.0128 as the downer gas velocity (Ugd) increased from 0 to 1m/s when Gswas 406kg/(m2s).