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首页> 外文会议>Spring 2000 meeting of the Western States Section of the Combustion Institute (WSS/CI spring 2000) >Mechanisms Governing Multi-Species Metal Capture by Kaolinite in High Temperature Combustion Environments
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Mechanisms Governing Multi-Species Metal Capture by Kaolinite in High Temperature Combustion Environments

机译：高温燃烧环境下高岭石捕获多种金属的机理

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An 18 kW, cylindrical (Inside Diameter = 15cm), 6m high, laminar, downflowrnfurnace was used to conduct experiments where aqueous metal solutions were injectedrnthrough the center of a natural gas flame at temperatures well above the metal dew points.rnKaolinite powder (Burgess 40) was injected approximately a meter below the flame alongrnthe furnace centerline. Metal, kaolinite, and metal/kaolinite product particles werernisokinetically sampled from the furnace (above the metal species dewpoints) and sizernsegregated using a Berner low pressure impactor. Samples were analyzed using flameionizationrnatomic absorption, Field Emission Scanning Electron Microscopy (FE SEM),rnand Energy-Dispersive Spectroscopy (EDS).rnMulti-metal interactions were kinetically investigated using a constantrntemperature/time profile for simplified run sets, while FE SEM and EDS were used tornstudy kaolinite particle morphological changes due to metal/sorbent interactions.rnIt was found that lead and sodium react with kaolinite at high temperatures (~rn1150 oC), causing a melt-like restructuring, which possibly aids the lead and sodiumrnreaction process and enhances the reaction of kaolinite with cadmium, by exposing newrnkaolinite particle surface active sites. Cadmium causes less melt-like restructuring ofrnkaolinite particles than lead and/or sodium. In fact, cadmium may actually inhibit thernmelt-like restructuring of kaolinite by lead and sodium.rnIn the case of sodium and lead bi-metal capture, sodium capture dominated.rnSodium capture was essentially unaffected by the presence of lead. Lead capture,rnhowever, was inhibited by the presence of sodium, either due to (1) Na displacement ofrnPb, (2) sodium reacting with “Na-Only” sites, which make adjacent (lead or sodium) sitesrnunavailable to lead, or (3) a sorbent deactivation reaction mechanism caused by the Nakaoliniternproduct. The third of these three possibilities is consistent with a self-inhibitingrnsorbent deactivation mechanism suggested in the literature for lead capture on kaolinite.
机译：使用18 kW圆柱形（内径= 15cm），高6m的层流向下流式熔炉进行实验，其中将金属水溶液通过天然气火焰的中心以远高于金属露点的温度注入到金属火焰中。高岭石粉（Burgess 40沿着炉子中心线在火焰下方约一米处注入）。金属，高岭石和金属/高岭石产品颗粒从炉中等动力学地取样（在金属物质的露点以上），并使用伯纳低压冲击器分离大小。使用火焰原子吸收法，场发射扫描电子显微镜（FE SEM）和能量分散谱（EDS）对样品进行分析。使用恒定温度/时间曲线动力学研究了多金属相互作用，以简化运行程序，同时对FE SEM和EDS进行了分析研究发现，铅和钠在高温（约rn1150 oC）下与高岭石反应，导致熔体状重组，可能有助于铅和钠的反应过程，并增强了金属与吸附剂之间的相互作用。通过暴露新的高岭石颗粒表面活性位，使高岭石与镉发生反应。与镉和/或钠相比，镉引起的高岭石颗粒的熔体状重构更少。实际上，镉实际上可能会抑制铅和钠对高岭石的类似熔体的重组。在钠和铅双金属捕获的情况下，钠的捕获占主导。钠的捕获基本上不受铅的存在的影响。但是，钠的存在会抑制铅的捕获，其原因可能是：（1）rnPb的钠置换；（2）钠与“仅钠”位反应，从而使相邻的（铅或钠）位无法利用铅；或（ 3）由Nakaoliniternproduct引起的吸附剂失活反应机理。这三种可能性中的第三种与文献中提出的在高岭石上捕获铅的自抑制吸附剂失活机理相一致。

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