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V2O5/炭基材料用于烟气脱硫脱硝的研究进展 总被引:7,自引:1,他引:6
燃煤烟气污染是我国可持续发展需要重点解决的环境问题.目前国内外使用的均是偏离排烟温度的单一污染物控制技术,几种技术串连实现多种污染物排放控制的成本较高.炭基材料由于其独特的性质,不仅可在排烟温度范围脱除烟气主要污染物--硫、硝、汞等,而且可以实现这些污染物的同时脱除.活性焦作为较为廉价的炭基材料,已经在国外实现了工业应用.过去10余年的研究表明,V2O5/活性焦的脱硫、脱硝、脱汞活性显著优于活性焦自身,也优于其他金属氧化物改性的活性焦,有望成为新一代烟气污染物排放控制技术的核心催化剂.本文总结了过去10年中V2O5/活性焦的研究进展,重点展示了脱硫和脱硝过程中的原理性认识,得出V2O5的低温氧化性是其促进多种污染物脱除的共性原因.可以看出,我国在这方面的研发中做出了重要贡献,形成了系统、深入的研究成果. 相似文献
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浸渍法制备了MoO3/TiO2催化剂,并对其进行了X射线衍射以及拉曼光谱分析。以正辛烷为溶剂,二苯并噻吩为模型硫化物组成模拟油品,以MoO3/TiO2为催化剂(以MoO3/Al2O3作对比),在H2O2-CH3COOH体系中对模拟油品的氧化脱硫进行了研究。考察了活性组分MoO3负载量、氧化剂用量、乙酸用量、反应时间以及反应温度等因素对二苯并噻吩脱除的影响。实验结果表明,相对MoO3/Al2O3,MoO3/TiO2具有更好的催化氧化脱硫性能;同时MoO3负载量、乙酸加入量和过氧化氢加入量以及反应温度对二苯并噻吩的氧化脱除均有影响。 相似文献
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将活性炭纤维毡用浸渍法进行处理,实验确定的浸渍条件为:浸渍混合液中含NH4VO3 质量分数为197%, CsNO3质量分数为068%,浸渍液温度70 ℃,1 250 mL浸渍液浸渍活性炭纤维(ACF) 20 g,每次浸渍时间6 h,重复浸渍3次。随后在N2保护下于250 ℃焙烧50 min,冷却至室温得到ACF催化剂。在实验室模拟试验装置上对ACF催化剂的烟气脱硫反应特性进行测试。实验结果表明,对烟气脱硫的反应活性次序为:KI-ACF>V2O5-Cs2O-ACF>空白-ACF。并且在烟气中含 SO20.225 mol·m-3,空速为2 400 h-1,反应温度348 K,测取实验数据,回归得到烟气在V2O5-Cs2O-ACF上脱除硫的反应动力学方程:dcSO2/dt=0.072exp(-7.843×103/RT)cSO21.025·cO20.579。 相似文献
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以十二胺表面活性剂为模板剂,钛酸四丁脂为无机母体源,采用溶胶-凝胶法制得稳定的TiO2凝胶,经焙烧得到掺杂型V2O5/TiO2脱硝催化剂粉末。分别用热重分析、X射线衍射、拉曼光谱和氮气吸附脱附法对催化剂进行了结构、比表面积和孔径的表征。在固定反应床,对氮氧化物的脱除活性进行了考察。结果表明,催化剂为锐钛矿,呈介孔结构,比表面积为118.5 m2·g-1,孔径(6~8) nm。钒以V=O键形式单层分布于TiO2中。催化活性评价结果表明,制备的催化剂在空速10 000 h-1和温度(180~450) ℃有较好的催化活性,空速对催化活性的影响主要在270 ℃以下。 相似文献
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γ-Al2O3在CeO2-La2O3催化还原SO2中的作用 总被引:3,自引:0,他引:3
考察了反应温度对γ-Al2O3、CeO2-La2O3和CeO2-La2O3/γ-Al2O3催化CO还原SO2到单质硫活性的影响。采用XRD表征了催化剂反应前后的物相变化。结果表明,温度过低或过高均不利于γ-Al2O3催化CO还原SO2的反应。γ-Al2O3的介入提高了CeO2和La2O3的分散性,使Redox 和COS两种反应机理在同一催化剂上的协同作用增强,使CeO2-La2O3/γ-Al2O3在催化还原SO2的反应中具有更低的反应温度和更高的活性。 相似文献
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Jianrong Ma Zhenyu Liu Qingya Liu Shijie Guo Zhanggen Huang Yong Xiao 《Fuel Processing Technology》2008
Supporting V2O5 onto an activated coke (AC) has been reported to significantly increase the AC's activity in simultaneous SO2 and NO removal from flue gas. To understand the role of V2O5 on SO2 removal, V2O5/AC is studied through SO2 removal reaction, surface analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) techniques. It is found that the main role of V2O5 in SO2 removal over V2O5/AC is to catalyze SO2 oxidation through a VOSO4-like intermediate species, which reacts with O2 to form SO3 and V2O5. The SO3 formed transfers from the V sites to AC sites and then reacts with H2O to form H2SO4. At low V2O5 loadings, a V atom is able to catalyze as many as 8 SO2 molecules to SO3. At high V2O5 loadings, however, the number of SO2 molecules catalyzed by a V atom is much less, due possibly to excessive amounts of V2O5 sites in comparison to the pores available for SO3 and H2SO4 storage. 相似文献
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在水平管式炉上研究了O2浓度、CO2浓度、温度及石灰石添加等各参数对O2/CO2气氛下徐州烟煤和龙岩无烟煤燃烧过程中SO2/NO排放特性的影响。结果发现,O2/CO2气氛下,烟煤和无烟煤燃烧SO2/NO的析出规律与空气气氛下不同,同等O2浓度下析出量比空气气氛下小。O2/CO2气氛下,随着O2浓度的提高,烟煤和无烟煤SO2/NO排放量均增大;随着CO2浓度的升高, SO2/NO排放量均减小。O2/CO2气氛下,石灰石添加对SO2排放的抑制作用低于空气气氛下;石灰石添加对NO的排放有一定减排作用。对煤灰的元素分析显示O2/CO2燃烧对SO2的抑制主要是由于煤灰的自固硫能力增强,而对NO的减排作用则是促进燃料N向其他含N气体的转换。 相似文献
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The carbonation characteristics of K2CO3/Al2O3 supported sorbent for CO2 capture was investigated with thermogravimetric apparatus(TGA),X-ray diffraction(XRD),scanning electron microscopy analysis(SEM)and N2 adsorption.The results showed that the carbonation rate of K2CO3 before being loaded on Al2O3 was slow.However,the K2CO3/Al2O3 upported sorbent showed excellent carbonation performance.The difference in carbonation behavior between K2CO3 nd K2CO3/Al2O3 supported sorbent was analyzed from the microscopic view.The analytical reagent K2CO3 sample was of monoclinic crystal structure and could react quickly with H2O in the experimental carbonation environment to produce K2CO38226;1.5H2O,which was unfavorable to carbonation reaction.When K2CO3was loaded on Al2O3,the surface area and porosity of the sorbent was improved greatly.So the carbonation properties of the K2CO3/Al2O3 supported sorbent was also improved. 相似文献
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Gas-phase elemental mercury capture by a V2O5/AC catalyst 总被引:3,自引:0,他引:3
Gas-phase elemental mercury (Hg0) capture by an activated coke (AC) supported V2O5 (V2O5/AC) catalyst was studied in simulated flue gas and compared with that by the AC. The study on the influences of V2O5 loading, temperature, capture time and flue gas components (O2, SO2, H2O and N2) shows that the Hg0 capture capability of V2O5/AC is much higher than that of AC. It increases with an increase in V2O5 loading and is promoted by O2, which indicates the important role of V2O5 in Hg0 oxidation and capture; it is promoted slightly by SO2 but inhibited by H2O; it increases with an increase in temperature up to 150 °C when Hg desorption starts. X-ray photoelectron spectroscopy analysis and sequential chemical extraction experiments indicate that the main states of Hg captured on V2O5/AC are HgO and HgSO4. Temperature programmed desorption experiments were also made to understand the stability of the Hg captured. 相似文献
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采用热力工况与实际煤粉炉相近的沉降炉实验装置,制备了不同环境气氛下(O2/N2及O2/CO2气氛)、不同燃尽率的煤焦试样,并采用低温氮吸附仪和扫描电子显微镜测定了其孔隙结构和表面形貌。结果表明,在相同的操作条件下,相同O2浓度的O2/CO2气氛下煤焦的燃烧速率较慢、燃尽率较低,各试样的孔比表面积和比孔容积均较小。两种气氛下燃尽过程孔结构参数(SBET和VBJH)均呈减小趋势,且在孔径变化较明显的区域内(<5 nm)在CO2气氛下煤焦的孔径分布较小且与煤种相关。SEM图像显示CO2气氛下的煤焦表面致密,孔隙较少,其定性结果与N2吸附法的定量测量结果吻合较好。 相似文献
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超声波/过氧化氢(US/H2O2)复合氧化过程在废水处理领域有很广泛的应用前景,但在动力学方面的研究很少,为此研究了US/H2O2工艺降解苯酚的动力学.结果表明,苯酚在单独超声波辐射(US)、过氧化氢(H2O2)氧化和超声波/过氧化氢(US/H2O2)协同下的降解均符合表观一级动力学.在单独的超声波辐射或者过氧化氢氧化下苯酚去除率很小,而在复合氧化过程US/H2O2工艺中有显著的提高,表明协同效应存在.苯酚去除的速率常数增强因子可达到6.904.进一步从US/H2O2系统中存在US、H2O2和羟基自由基(8226;OH)3部分协同作用的降解机理,推导出了简化的机理动力学模型,很好地反应过氧化氢浓度过量条件下苯酚的降解. 相似文献
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A novel Pd/Al2O3 catalyst prepared by glow discharge plasma technology is reported.The results of H2-chemisorption indicate that palladium dispersion of the plasma-prepared Pd/Al2O3 reaches 29.7%,which is about 5 times higher than Pd/Al2O3 prepared by conventional preparation.Meanwhile,the particle diameter of the plasma-prepared catalyst is 3.8 nm, but the particle diameter of the conventional catalyst is 20.4 nm.Such plasma-prepared Pd/Al2O3 catalyst shows a higher activity for catalytic combustion of methane than the conventional catalyst.Methane conversion reaches 90% at 400 ℃, but it is only near 30% for the conventional catalyst at the same temperature. 相似文献
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对静电纺丝法制备的TiO2和TiO2-V2O5纳米纤维进行光催化脱除模拟烟气中Hg0的研究。对纳米纤维进行了SEM、TEM、XRD、BET和UV-Vis检测。结果表明TiO2-V2O5纳米纤维为锐钛矿,V2O5高度分散在TiO2中。纤维直径在200 nm左右,由粒径为10 nm左右的微粒组成。掺杂V2O5后,纤维的吸光范围扩大,在可见光范围内的吸光度比纯TiO2时有了很大提高。实验研究了不同光照条件、V2O5的掺杂量和循环次数对脱汞的影响,分析了TiO2-V2O5催化脱汞的机理。当V2O5的质量含量为3%时,TiO2-V2O5在可见光下的脱汞率可达到66%,比纯TiO2时的7%有了显著提高;纤维的脱汞性能稳定,多次循环后紫外光和可见光下的脱汞率仍分别保持在80%和65%左右。电子的跃迁和电子、空穴的快速分离是TiO2-V2O5在可见光下脱汞率提高的主要原因。 相似文献
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H2 regeneration of an activated carbon supported vanadium and cobalt oxides (V2O5-CoO/AC) catalyst–sorbent used for flue gas SO2 removal is studied in this paper. Elemental sulfur is produced during the H2-regeneration when effluent gas of the regeneration is recycled back to the reactor. The regeneration conditions affect the regeneration efficiency and the elemental sulfur yield. The regeneration efficiency is the highest at 330 °C, with SO2 as the product. The production of elemental sulfur occurs at 350 °C and higher with the highest elemental sulfur yield of 9.8 mg-S/g-Cat. at 380 °C. A lower effluent gas recycle rate is beneficial to elemental sulfur production. Intermittent H2 feeding strategy can be used to control H2S concentration in the gas phase and increase the elemental sulfur yield. Two types of reactions occur in the regeneration, reduction of sulfuric acid to SO2 by AC and reduction of SO2 to elemental sulfur through Claus reaction. H2S is an intermediate, which is important for elemental sulfur formation and for conversion of CoO to CoS that catalyzes the Claus reaction. The catalyst–sorbent exhibits good stability in SO2 removal capacity and in elemental sulfur yield. 相似文献
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以CO2为沉淀剂,Na2SiO3为硅源,制备了SiO2包覆纳米CaCO3吸附剂。TEM测试证实纳米CaCO3表面包覆一层SiO2膜, 用SEM & EDX 测试5个包硅样品Si含量为0.67%~4.93%。采用TGA考察吸附剂的分解温度及600℃、20% CO2条件下的吸附性能。结果表明:采用CO2沉淀法包覆SiO2后,与未包硅的纳米CaCO3相比,分解温度降低9~42℃。纳米SiO2/CaCO3吸附剂的循环吸附率、吸附容量、吸附速率均随Si含量的减小先增加后降低。Si含量为1.05%的纳米SiO2/CaCO3吸附剂显示最佳吸附性能,第1、5次循环吸附容量分别为8.9、6.0 mol·kg-1,与未包覆SiO2的纳米CaCO3相比,分别提高11%、50%,同时在第5次循环快反应段吸附速率较纳米CaCO3提高10%。与纳米CaCO3相比,包硅后的吸附剂具有较高的吸附容量和循环吸附率,循环稳定性较好。 相似文献