共查询到19条相似文献,搜索用时 78 毫秒
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以市政污泥为原料热解制备污泥炭,开展了污泥炭催化还原NO的实验研究。考察了不同热解温度(400℃、600℃和800℃)和污泥初始含水率(0、66%和80%,质量分数)条件下热解制备的污泥炭的脱硝性能。研究表明,污泥炭中包含大量铁元素(41.1mg/g),提高热解温度可促进污泥炭中亚铁化合物(Fe2P和FeS)的生成,使铁元素具备催化还原NO的能力,从而显著提高污泥炭的脱硝效率。提高污泥热解初始含水率可显著提高污泥炭比表面积,污泥炭对NO的低温还原能力也随初始含水率提升而显著提高。通过对污泥炭的比表面积、X射线衍射(XRD)和傅里叶红外(FTIR)分析表征,结果表明污泥炭中亚铁化合物的生成是影响NO转化的关键影响因素,而比表面积和表面官能团类型对污泥炭脱硝反应并无明显影响。 相似文献
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以废水污泥热解产生的污泥热解炭为原料,通过酸洗、活化、负载Fe、H2还原等方式考察不同污泥热解炭样品对脱硝性能的影响。结果表明,污泥原样中的Fe2P、FeS等低价态的铁具有良好的脱硝性能,450~500℃时最大脱硝效率达到81%。经过HNO3酸洗和KOH活化后的污泥热解炭,因为去除了Fe2P、FeS等低价态的铁,脱硝效率大幅下降,在450~500℃的最大效率分别仅为30%和53%。而热解污泥负载样中的Fe主要以Fe2O3形式存在,其最大脱硝效率在450~500℃时只有50%。经过H2还原后,负载样中的Fe2O3被还原为Fe2P、FeS等低价态的铁,其最大脱硝效率在450~500℃时上升至94%。 相似文献
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稻壳灰通过焚烧稻壳得到,具有较大的比表面积、较多的孔和较高的碳含量,可作为碳源还原氮氧化物.本论文采用X射线荧光分析仪、高速比表面积和孔结构分析仪、扫描电镜分析稻壳灰的化学成分、微观结构和组成、比表面积等物理化学特性,并探究了稻壳灰对水泥窑炉烟气中氮氧化物的还原转化效率.结果表明,稻壳灰渣有更多大而浅的孔,内部呈类蜂窝状结构,有利于吸附氮氧化物气体.稻壳灰中含有大量的碳,可以作为固体还原剂,有效还原水泥窑炉烟气中的氮氧化物,在850℃时脱硝效率可达到60%以上,较佳的脱硝反应温度为850℃左右,一定浓度的CO对C-NO还原过程有贡献,氧浓度为0.5%时有较高的CO生成量,其脱硝效率也较高.稻壳灰的化学成分与水泥原料相似,可以将一定比例稻壳灰均匀加入水泥生料中,在水泥分解炉中进行氮氧化物的还原,减少污染气体的排放. 相似文献
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氮氧化物选择催化还原的研究进展 总被引:11,自引:2,他引:9
氮氧化物(NOx)是大气的主要污染物之一。含氧气氛中,在催化剂的帮助下使还原剂与废气中的NOx反应并将其还原为N2的催化过程称为选择催化还原(SCR),是目前研究较多的消除NOx污染的方法之一。综述了选择催化还原方法的研究现状与应用前景。 相似文献
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煤焦直接还原脱除烟道气氮氧化物 总被引:1,自引:0,他引:1
选用3种不同煤焦,采用程序升温和恒温实验方法,在固定床上考察了不同实验条件下的NO转化率和C对NO选择性,分析了煤焦脱硝的机理和影响因素。实验结果表明:NO和O2在煤焦表面发生化学吸附所形成的络合物在脱硝过程中起着关键作用,影响C-NO反应和C-O2反应的竞争与协作关系。在所考察的煤焦中锡林浩特褐煤焦脱硝效果最好,当温度为723 K时烟道气中NO还原率可达99%;在温度623~923 K、O2浓度0~5%范围内,提高温度和O2浓度均有利于提高NO转化率,而降低O2浓度有利于提高C对NO选择性;烟道气中NO浓度越高,其转化率越低,但C对NO选择性越高。 相似文献
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氮氧化物是形成酸雨和光化学烟雾的主要物种和引发物,消除氮氧化物污染是环境保护中的重点和难点。选择性催化还原作为一种有效脱除氮氧化物的方法,在近年来得到了广泛深入的研究。本文对有关催化体系的文献进行了总结。 相似文献
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氢气还原氧化铁动力学的研究(英文) 总被引:1,自引:0,他引:1
Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed.Influence of external diffusion,internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been deter-mined.In the experiments,in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe2O3 to Fe3O4,the reaction temperatures were set between 440 °C and 490 °C.However,in order to distinguish the reduc-tion of Fe3O4 to FeO from that of FeO to Fe,the reaction temperature in the experiment was set to be greater than 570 °C.Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data. 相似文献
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为了实现污泥的资源化,通过微波热解与化学活化相结合的方法制备污泥吸附剂。采用亚甲基蓝吸附值分析、扫描电镜分析、X射线光电子能谱分析和X射线衍射能谱分析的方法研究了活化剂浓度、干污泥与活化剂浸渍液的固液比、微波辐射功率和微波辐射时间对污泥吸附剂吸附性能的影响。结果为:在活化剂Zn Cl2浓度为40%、固液比1:2、微波辐射功率650W和微波辐射时间10min的条件下,所制备污泥吸附剂的吸附性能达到最佳效果,其亚甲基蓝吸附量为53.21mg·g-1,比表面积为130.364m2·g-1。 相似文献
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The reduction of the nickel oxide, NiO, by methane was investigated in this work. The thermogravimetric technique was used for the determination of kinetic parameters for the reaction. The reaction was carried out in the temperature range of 600–725 °C, at atmospheric pressure with porous pellets prepared from nickel oxide powder with a mean particle size of 0.026 μm. The conversion‐time data have been interpreted by using the grain model. Complete conversion can be achieved in 11 min at 725 °C, which is shorter than the time required by carbon, i.e., ca. 120 min at 1000 °C. This faster reduction in comparison with carbonthermal reduction is attributed to the high carbon activity in methane. For the first order reaction with respect to methane concentration, the activation energy is found to be 63.9 kcal/g mol. 相似文献
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Bismuth Oxide Nanoparticles by Flame Spray Pyrolysis 总被引:6,自引:0,他引:6
Bismuth oxide nanostructured particles were made via the flame spray pyrolysis (FSP) of bismuth nitrate that had been dissolved in a solution of ethanol/nitric acid or in acetic acid. These self-sustaining spray flames produced tetragonal β-Bi2 O3 . The use of ethanol/nitric acid solutions resulted in a mixture of hollow, shell-like, and solid nanograined particles. The particle homogeneity was improved as the content of acetic acid in the precursor solution increased. Solid bismuth oxide nanoparticles were prepared consistent with percolation theory, accounting for the specific volume of the product and the precursor. Using pure acetic acid as the solvent, the effect of FSP variables on spray flame and product powder characteristics was investigated. The specific surface area of the Bi2 O3 particles could be controlled over a range of 20–80 m2 /g by the liquid feed and oxygen gas flow rates for powder production rates of 6–46 g/h. 相似文献