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改性石灰中温流化态干法争化HCl的试验研究 总被引:2,自引:0,他引:2
微量的NaOH、Na2CO3、KOH和K2CO3以特殊方式添加到石灰类物质中以后形成改性石灰类吸收剂.在310~430℃温度段的流化床反应器内对净化HCl气体效果的试验研究结果表明:(1)改性石灰类吸收剂对HCl的净化效率较纯石灰类高,并且净化效率随反应温度上升而上升;(2)使用改性CaO和Ca(OH)2做吸收剂的流化床反应器对HCl具有较高的净化效率(>90%),以流化态运行方式对烟气中的酸性气体实施干式净化,可以达到排放标准;(3)碱性添加物处理后的CaO和CaCO3在一定条件下可与Ca(OH)2竞争,有望替代后者用作干式吸收剂. 相似文献
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水合肼处理CaCO3中高温净化焚烧烟气的研究 总被引:1,自引:0,他引:1
用水合肼对CaCO3进行处理,并将处理后的CaCO3用于中高温段净化焚烧烟气中的Hcl和NO。研究结果显示,因肼在加热过程中会分解甚至燃烧产生大量气体,使处理后的CaCO3在煅烧后比普通CaCO3的颗粒更细,反应活性更高,最终水合肼处理CaCO3吸收HCl气体的反应率随温度的升高而增大。当肼处理CaCO3中的肼含量在肼钙摩尔比为0.1-0.3的范围内变化到0.15时,其吸收HCl气体的反应率为最大。但当肼钙摩尔比大于0.15后,CaCO3在受热后板结而导致反应率降低。肼处理CaCO3在450-650℃范围内、烟气中氧量高于13%的条件下显示了对NO的还原效率,这是由于肼在此条件下对NO具有还原能力;而常用的还原剂氨在问样条件下对NO不具备还原能力。使用肼处理CaCO3可望实现在中高温段同时净化焚烧烟气中的酸性气体和NO。 相似文献
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NO2对中温干法脱硫反应影响的实验研究 总被引:1,自引:0,他引:1
利用鼓泡床反应器对NO2对中温干法脱硫反应的影响开展了实验研究.分别采用分析纯CaO和工业级石灰两种物质作为吸收剂,在250℃和350℃两个反应温度下研究NO2对吸收剂转化率的影响.结果表明,NO2的存在可以提高吸收剂转化率;250℃下NO2的作用显著高于350℃;250℃下NO2浓度的增加对吸收剂转化率基本没有影响;在350℃时,对于分析纯CaO,NO2浓度的增加降低了吸收剂转化率,这主要是由于SO2与NO2的竞争反应引起的;工业级石灰内含杂质较多,对一些反应有催化作用,因而其反应现象与分析纯CaO略有不同. 相似文献
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本文以无烟煤为前驱体,采用KOH活化法制备了煤基活性炭,并以NH4I为改性剂对活性炭进行改性,用于燃煤烟气中汞的脱除。实验研究了负载的NH4I的质量分数、烟气温度以及烟气成分对改性活性炭脱汞性能的影响。研究结果表明,最佳的NH4I负载质量分数为0.07;在80~180℃的温度范围内,随着温度的升高,活性炭的脱汞效率逐渐降低。烟气中的O2、CO2、NO、HCl等组分对改性后的活性炭的脱汞效率具有一定的促进作用,SO2则有明显的抑制作用;但由于改性活性炭具有较好的抗硫效果,当烟气中含有微量的SO2时,活性炭的平均脱汞效率仍可达到87.95%。采用热再生法对改性活性炭进行再生,结果表明,400℃下再生的活性炭的脱汞率为95.82%,但随着再生次数的增加,活性炭脱汞效率不断降低。 相似文献
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中低温下钠碱对氢氧化钙干式吸收HCl气体的改良 总被引:2,自引:1,他引:1
用很稀的NaOH、Na2CO3、NaCl溶液代替纯水消化生石灰,测试并比较生成的Ca(OH)2与不含这些物质的Ca(OH)2在中低温段(200~300℃)净化酸性气体HCl的反应能力.试验表明用钠碱NaOH和Na2CO3溶液消化生成的Ca(OH)2较用纯水和NaCl溶液消化生成的Ca(OH)2具有更高的反应能力,即钠碱对Ca(OH)2具有改良作用.初步研究表明,含有钠碱的氢氧化钙反应能力较高的主要原因有:(1)孔容积和比表面积提高;(2)孔隙率分布改善,最佳孔径区(50~200A)内的BJH孔隙率和比表面积递增密度增大;(3)反应产物层疏松多孔,减少了扩散阻力. 相似文献
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In microscopy studies of 19th‐century cement stone, we found free lime in the form of darkened spherical structures, as they were described in the literature already. When trying to determine their phase composition by Raman spectroscopy, we encountered contradictive assignments in literature spectra of the lime phases CaO, Ca(OH)2 and CaCO3 and observed strong spectral features that have been ignored or erroneously assigned so far. In this study we present Raman spectra of pure lime phases and of a naturally grown calcite crystal, burnt limestone (quick lime, mainly CaO), aged slaked lime putty (mainly Ca(OH)2), and carbonated lime putty (mainly CaCO3). Based on the results, we shed light mainly onto these two questions: (1) Does CaO have a Raman spectrum? (2) Which features in the spectra are luminescence bands that could be (and already have been) misinterpreted as Raman bands? We proof our assignment of luminescence bands in lime phases by using three different laser wavelengths for excitation, and give hypotheses on the origin of the luminescence as well as practical advices on how to identify these misleading features in Raman spectra. This article is mainly addressed to users of Raman spectroscopy in different fields of material analysis who might not be aware of the presence of interfering bands in their spectra. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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石灰是中国古代最早使用的重要胶凝材料,广泛应用于房屋、墓葬、城墙、堤坝等古代建筑工程中。古人还在石灰灰浆中添加糯米浆、动物血液、植物汁液、红糖、桐油、纸筋、秸草等有机材料以增进其性能。此外,中国古代还使用石灰、粘土和砂石组成现在称为"三合土"的混合石灰材料以构筑墓葬、城墙和水利工程等建筑墙体。在古建筑遗址的修复和保护工作中,本着"修旧如旧"的原则,必须对古建筑修建所采用的原材料和施工工艺进行分析研究,从而为修复工作提供科学可靠的依据。本文综述了在对中国古代建筑石灰灰浆的分析中所采用的光谱分析技术,包括拉曼光谱、红外光谱、X射线衍射和X射线荧光光谱,以及扫描电子显微镜、热重分析等其它一些分析技术,讨论了各种分析技术的用途、优势和劣势。 相似文献
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本文采用理论推导得到了生石灰粉和飞灰物料团的脱硫反应模型,并采用此模型比较计算了颗粒团大小、颗粒团空隙率、单个颗粒大小以及生石灰颗粒所占比例f对颗粒团脱硫反应的影响,计算结果合理,说明本文推导得到的生石灰粉和飞灰物料团脱硫反应模型是科学合理的。 相似文献
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Transmission electron microscopy and selected area electron diffraction performances were used to characterise the microstructure of a multicomponent soda-lime silicate glass, the composition of which corresponds to the miscibility gap in the SiO2—Na2O system. It has been stated that phase separation already exists in as prepared specimens, and the Na2O-rich phase occurs in the form of nearly spherical droplets. The microstructure of these glasses was modified by high-temperature annealing in air and hydrogen, by irradiation with soft X- and gamma-irradiation and by mechanical stretching. In this way the quantity, size, shape and distribution of these particles was changed. A variety of induced changes affects the structure-sensitive properties of commercial soda lime silicate glasses, which can be potentially useful for new applications. 相似文献
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Maja Vojnić Kortmiš 《辐射效应与固体损伤》2013,168(11-12):978-985
ABSTRACTESR readout improvement of gamma-irradiated soda–lime glasses is presented by considering the dose-dependent differences in temperature behaviour of the radiation-induced signal and background signal, and effective difference in g-values of those two signals. Our experimental results demonstrate that the dose-dependent temperature behaviour can improve the ESR signal response for 30–80% in the dose range below 20 Gy by detection at 200?K compared to the room temperature signal readout. The application of improvement can be expected in the low-level dose range where the radiation-induced signal is comparable with an inhomogeneous background signal. 相似文献