Investigation on the transfer-transformation behavior of beryllium during coal combustion
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摘要: 通过热力学平衡模拟计算煤燃烧过程中铍的形态转化, 采用高温真空管式炉进行含铍化合物与矿物的固固反应实验, 以及富铍煤中加入添加剂的燃烧实验, 通过X射线衍射仪 (XRD)、X射线荧光探针 (XRF) 以及电感耦合等离子质谱仪 (ICP-MS) 揭示煤燃烧过程中铍的迁移转化规律。结果表明, 模拟计算发现铍只与含铝化合物反应生成BeAl2O4和BeAl6O10, 同时固固反应实验也印证了这一结论, 但反应温度在1000℃左右, 明显高于模拟计算温度650℃。添加Al2O3的富铍煤在燃烧时, 由于铍与Al2O3发生反应, 铍的释放率明显降低, 最高降低33%以上; 添加了伊利石的富铍煤, 由于伊利石与铍的反应温度高于Al2O3, 其抑制作用弱于Al2O3; 而高岭石由于与铍的反应温度过高, 在高岭石与铍发生反应产生抑制效果之前, 部分铍已经在燃烧过程中释放出去, 因此, 抑制效果最差。Abstract: The thermodynamic equilibrium calculation was conducted to estimate the beryllium conversion in the combustion process of coal, and the high temperature vacuum tube furnace was used to research the beryllium compounds reaction with other solid substances and the coal combustion experiments by adding sorbents. X-ray diffraction (XRD), X-ray fluorescence probe (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS) were used to reveal the transformation behavior of beryllium during coal combustion. The results indicate that the beryllium only reacts with aluminum compounds and the reaction resultants are BeAl2O4 and BeAl6O10, the solid-solid reaction experiments are in agreement with thermodynamic calculation results, but the actual reaction temperature is about 1000℃, far above the thermodynamic calculation temperature 650℃. Because beryllium reacts with Al2O3 in combustion, the release rate of beryllium in the coal sample added with Al2O3 reduces greatly by up to 33%. Moreover, the inhibition of illite to beryllium release for coal combustion with addition of illite is weaker owing to a higher reaction temperature of illite with beryllium than that of Al2O3. Kaolinite, because its reaction temperature with beryllium is too high, has the lowest inhibition effect.
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Key words:
- :beryllium /
- coal combustion /
- transformation /
- inhibition
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表 1 煤的工业分析和元素分析
Table 1 Proximate and ultimate analysis of coal
Coal sample Proximate analysis w/% Ultimate analysis wd/% Mad Ad Vd FCd C H O N S Wulantuga coal 15.14 12.28 41.26 46.46 58.76 4.65 21.74 0.91 1.66 表 2 灰成分分析
Table 2 Coal ashes analysis
Major ash components w/% TiO2 SO3 Al2O3 SiO2 K2O CaO Fe2O3 0.56 6.63 12.89 42.64 0.52 4.08 31.52 表 3 燃煤过程中铍的释放率
Table 3 Beryllium release in the combustion process of coal
Coal sample Coal w/% Coal with 2% alumina w/% Coal with 2% Kaolinite w/% Coal with 2% illite coal w/% 800℃ 11.56 8.27 12.59 11.15 1000℃ 15.75 13.56 14.99 13.66 1200℃ 29.35 16.47 25.60 23.11 1400℃ 55.92 22.27 37.10 26.62 表 4 灰熔点参数
Table 4 Ash fusion point
Coal sample Coal t/℃ Coal with 2%
alumina t/℃DT 986 1330 ST 1096 1422 FT 1122 1490 -
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