On the application of surface ionization detector for the study of alkali capture by kaolin in a fixed bed reactor
On the application of surface ionization detector for the study of alkali capture by kaolin in a fixed bed reactor
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DOI：
10.1016/j.fuel.2003.10.014
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发表时间：
2004-05
期刊：
影响因子：
7.4
通讯作者：
K. Tran;K. Iisa;M. Hagström;B. Steenari;O. Lindqvist;J. Pettersson
中科院分区：
文献类型：
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作者：
K. Tran;K. Iisa;M. Hagström;B. Steenari;O. Lindqvist;J. Pettersson
据信，碱金属（主要是钾）与生物质中的其它形成灰分的无机组分一起是燃烧生物质的流化床锅炉中的床附聚的原因。该问题的解决方案是通过无机固体添加剂如高岭土捕获燃烧期间从燃料释放的碱蒸气。在本研究中，在装有在线碱检测器的固定床反应器中，研究了氯化钾蒸气的捕集。该检测器，这是基于表面电离，是能够操作在碱金属浓度低到那些遇到的反应后，生物质燃烧过程中与高岭土（1ppb的顺序）。在850 °C的反应器温度下进行高岭土粉末捕获KCl的各种实验。高岭土去除气相中高达99%的碱物质。当KCl浓度降低时，效率略有下降。在650 °C空气中研究了高岭土添加对木材燃烧过程中碱金属释放的影响。在热解过程中，当高岭土与木材混合时，由于高岭土添加剂中的碱金属杂质的释放，碱金属释放略有增加。焦炭燃烧过程中的碱金属释放量减少到原始值的约50%。随着高岭土添加量的增加，减少量增加。总的来说，高岭土的加入抑制了碱金属从木材中释放约20%。
Alkali metals, mainly potassium, together with other ash forming inorganic components in biomass are believed to be responsible for bed agglomeration in fluidized bed boilers burning biomass. A solution to the problem is to capture alkali vapor released from the fuel during combustion by inorganic solid additives such as kaolin. In this study, the capture of vaporous potassium chloride was investigated in a fixed bed reactor equipped with an on-line alkali detector. The detector, which is based on surface ionization, is capable of operating at alkali metal concentrations as low as those encountered after reaction with kaolin during biomass combustion (of the order of 1ppb). Various experiments of KCl capture by kaolin powder were made at a reactor temperature of 850 °C. Kaolin removed up to 99% of alkali species in gas phase. The efficiency slightly decreased when KCl concentration decreased. The effect of kaolin addition on the release of alkali metals during wood combustion was studied at 650 °C in air. During pyrolysis, the alkali metal release increased slightly when kaolin was mixed with the wood due to the release of alkali metal impurities in the kaolin additive. The alkali metal release during char combustion was reduced to approximately 50% of the original value. The reduction increased as the amount of kaolin addition increased. Overall, the addition of kaolin suppressed the alkali metal release from the wood by approximately 20%.