综合热分析法研究催化剂对煤粉燃烧过程的影响

利用综合热分析仪研究了Ce2(CO3)3, CeO2, CaCO3, CaO 四种化合物对煤粉燃烧过程的影响. 重点研究了稀土金属化合物Ce2(CO3)3在不同添加量和不同粒度时对煤粉燃烧过程的影响. 结果表明,Ce2(CO3)3能够显著促进煤粉的燃烧过程,降低着火点温度. 添加量为1.0%时,煤粉着火温度降低约30℃,助燃性能优于其他3种催化剂. 在添加量小于1.0%时,Ce2(CO3)3添加量越大,着火温度越低. 在Ce2(CO3)3不产生团聚的情况下,催化剂粒径越小,煤粉的着火温度越低.     

适合低质煤燃烧的催化助燃剂研究

以低质煤为原料,浸渍法制备催化剂,利用综合热分析仪研究了KNO3,DF,DY和DN四种助燃组分对低质煤催化燃烧反应性的影响.结果表明,不同组分及其添加量对低质煤助燃效果不同;由KNO3,DF,DY,DN和十二烷基苯磺酸钠以一定比例组成的复合催化助燃剂(FKYN)可使低质煤煤粉着火点降低12.3℃,最大失重率点温度降低8℃,燃烬温度降低13.1℃,煤灰中含碳量显著降低.催化剂的分散程度对助燃效果有显著影响,以5%煤粉为分散剂时,催化效果最佳.     

含能助燃催化剂及其应用

<正>本发明涉及一种含能助燃催化剂。所述含能助燃催化剂主要由以下质量份数比的组分构成:杂醇油25-28份、乙醇14-18份、四氢化萘16-20份、环戊醇14-16份、巴豆醛18-22份、2-吡咯烷酮1-2份、纳米氧化稀土1.5-3份和含能笼型硼化物或其衍生物2-3份。本发明的含能助燃催化剂可以应用在液体、气体的烷烃燃料中,形成含能复合燃料,提     

催化剂对兖州煤泥燃烧特性的影响

为充分利用煤泥资源 ,在其中添加助燃催化剂 ,以期提高它的燃烧热效率 .对比研究了硝酸钾催化剂及 TF配方助燃催化剂对兖州煤泥着火温度、燃尽温度和放热面积的影响 .研究结果表明 ,添加催化剂后 ,煤泥着火温度降低 ,燃尽温度提前 ,且燃烧放热量增加 ;TF配方催化剂对煤泥催化燃烧的效果优于硝酸钾催化剂 .探讨了助燃催化剂对煤催化燃烧的作用机理 .     

含能助燃催化剂及其应用

正本发明涉及一种含能助燃催化剂。所述含能助燃催化剂主要由以下质量份数比的组分构成:杂醇油25-28份、乙醇14-18份、四氢化萘16-20份、环戊醇14-16份、巴豆醛18-22份、2-吡咯烷酮1-2份、纳米氧化稀土1.5-3份和含能笼型硼化物或其衍生物2-3份。本发明的含能助燃催化剂可以应用在液体、气体的烷烃燃料中,形成含能复合燃料,提升燃料的热效能,有效替代乙炔,用于金属火焰焊     

催化剂对混合煤在快速热解过程中的影响

热解对燃烧过程有很重要的影响,助燃催化剂KMnO4,Fe2O3,MnO2和CaO对煤粉在快速加热条件下的燃烧过程具有催化作用。采用H2/Ar等离子体热解试验装置和快速升温热解红外连用试验装置,对混合煤粉的快速热解过程进行了研究,得到了助燃催化剂有利于煤的快速热解产生挥发分。KMnO4,Fe2O3,MnO2的催化作用机理与其空价层原子轨道有关,CaO的催化作用机理与其本身的碱性特征有关。     

乳液法假均相催化剂制备及在煤液化中的应用

以洗油/Span80-Tween80/水相制成W/O型S~(2-)和Fe~(2+)前驱体乳液,双乳液经硫化制备铁基假均相催化剂,并对乳液稳定因素、乳液法制催化剂机理、催化剂稳定性及其对西沟煤的液化性能进行了研究.结果表明:稳定乳液的制备条件为油水质量比9∶1,Fe~(2+)乳液和S~(2-)乳液复配乳化剂的加入量(质量分数)分别为15.61%和18.36%,HLB值(亲水疏水平衡值)分别为7.3和6.7,机械搅拌速率6 000r/min,乳化时间15min,乳化温度20℃~30℃.所制假均相催化剂体系,沉降速率为5.24×10~(-7) cm/h.TEM表征得到催化剂粒径在100nm左右,呈球形形貌.该催化剂用于西沟煤加氢液化,油产率较使用普通商用Fe_2O_3时提高4.04%.     

油剂及其他助剂

20064316用四丁基氧化钛和新型商用二氧化钛基催化剂合成聚对苯二甲酸乙二酯的比较Finelli L.….;Journal of Applied Ploymer Science,2004,92(3),p.1887(英)多年来,用钛基催化剂合成聚对苯二甲酸烷撑酯已是众所周知。到目前为止,有机钛酸盐化合物作催化剂,工业规模上仅用于合     

商用选择性催化还原催化剂SO_2氧化率控制研究进展

选择性催化还原(SCR)法作为目前最成熟的氮氧化物(NO_x)控制技术被广泛地应用于燃煤电站等行业的NO_x排放控制过程,其核心是催化剂。商用SCR催化剂一般是以V_2O_5为活性组分、WO_3(或MoO_3)为催化助剂、TiO_2为载体的V_2O_5-WO_3(MoO_3)/TiO_2催化剂。该催化剂在催化NO_x还原的同时也会催化SO_2的氧化,生成的SO_3会给脱硝工程带来一系列的不利影响。基于此,本文首先介绍了钒钛催化剂催化氧化SO_2的反应机理及其研究进展,随后综述了影响SO_2氧化率的主要因素,主要包括催化剂中V_2O_5含量、催化助剂、飞灰、壁厚及烟气成分、反应温度等,并详细地分析了各因素对SO_2氧化率的影响特性。在此基础上,综述了控制SCR催化剂SO_2氧化率的方法。最后指出SO_2氧化率控制技术的发展对低SO_2氧化率脱硝催化剂的开发、失活催化剂的再生以及废弃催化剂的回用等均有着重要意义,是未来研究和开发的重点方向。     

负载型铈钛SCR催化剂反应机理探究

采用水热法合成了TiO_2纳米颗粒,并负载了CeO_2进行选择性催化还原(SCR)氮氧化物的实验研究,发现TiO_2纳米颗粒为载体时,催化剂在整个温度区间内的活性都高于商用P25为载体的催化剂。采用原位红外对CeO_2/TiO_2催化剂SCR反应机理进行相关研究,发现在250℃下该反应主要遵循Eley-Rideal反应机理,即吸附于Lewis酸性位点上的NH3与气相NO发生反应生成N2和H2O,被还原的Ce3+与O_2发生作用重氧化为Ce4+。     

不同硅铝比HZSM-5分子筛对合成气一步法制二甲醚的影响

采用固定床高压反应装置,以工业用（CuO／ZnO／Al2O3）作为甲醇合成催化剂,四种不同硅铝比（硅铝比为25、38、50和150）的HZSM-5作为甲醇脱水催化剂,二者机械混合制备出一步法合成二甲醚双功能催化剂。考察了催化剂中脱水组分（HZSM-5分子筛）的硅铝比对二甲醚合成反应的影响,并通过BET、XRD和NH,-TPD等手段对催化剂进行表征。结果表明,一步法合成二甲醚催化剂中脱水组分HZSM-5的最佳的硅铝比为50。     

Modified iron-molybdate catalysts with various metal oxides by a mechanochemical method: enhanced formaldehyde yield in methanol partial oxidation

A mechanochemical method was employed to prepare modified iron molybdate catalysts with various metal salts as precursors. The physicochemical properties of the iron molybdate catalysts were characterized, and their performances in catalyzing the reaction from methanol to formaldehyde (HCHO) were evaluated. Iron molybdate catalysts doped with Co(NO₃)₂·6H₂O and Al(NO₃)₃·9H₂O resulted in high HCHO yields. Compared with a commercial catalyst, the HCHO yields in the reaction with the modified catalyst at an optimal Co/Mo molar ratio reached 97.37%. According to chemical state analysis, the formation of CoO and the efficient decrease in the MoO₃ sublimation rate could be important factors enhancing the HCHO yield in reactions catalyzed with iron molybdate doped with different Co/Mo mole ratios.     

Anodic Alumina Supported Pt Catalyst for Total Oxidation of Trace Toluene

Featuring an assembly of identical pores, through-pore anodic alumina (AAO) makes an ideal monolith-like cat-alyst support for volatile organic compound (VOC) combustion. This work employs the oxidatio...     

Methane oxidation on alumina supported palladium catalysts: Effect of Pd precursor and solvent

Palladium precursors and solvents were studied for their effects on the activities of alumina-based palladium catalysts in methane combustion and the resistance of the catalysts to thermal aging. The properties of the catalysts were compared with those of a commercial reference. The palladium precursors were Pd(propionate)₂, Pd(acetate)₂ and Pd(acetyl acetonate)₂ and the solvents were acetone, acetic acid, propionic acid and toluene. Catalysts were prepared by the wet impregnation method.Catalysts were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). The surface areas were measured by Brunauer–Emmett–Teller method (BET). Acidity of the alumina support was measured by NH₃ desorption. Activities of the catalysts in methane oxidation were screened under lean burn conditions.In methane oxidation with fresh catalyst, the best performance was obtained with a combination of Pd(acetate)₂ and acetic or propionic acid. The light-off temperatures of the fresh catalysts (562 K and 557 K, respectively) were slightly lower than the light-off temperature (567 K) of the commercial reference. Differences between the light-off temperatures of the aged and fresh catalysts were least when the catalysts were prepared with Pd(acetyl acetonate)₂ as Pd precursor and in acetic or propionic acid as solvent: +12 K and +18 K, respectively. The corresponding value for the reference was +64 K. For several of the fresh catalysts, conversion in methane oxidation at 623 K was over 90%. A comparison of methane combustion and NH₃ desorption results indicated that acidity of the support material affects catalysts activity.     

商用蜂窝式SCR催化剂脱除NO_x试验研究

为了评价燃煤电厂广泛采用的选择性催化还原工艺对不同形态NO_x的脱除效果,以某商用蜂窝式SCR催化剂为例,在SCR脱硝试验装置上研究了氧量、温度、空速、氨氮摩尔比等反应条件对NO、N_2O和NO_2脱除过程的影响。结果表明,氧量可以促进NO氧化以及NO与氨的催化还原反应;高温可以促进NO的脱除和氨气氧化为N_2O;空速升高会导致NO脱除率先升高后降低;氨氮摩尔比提高在促进NO脱除的同时会增加氨逃逸;与NO_2可以完全脱除相反,N_2O与氨气不发生反应。因此,为真正实现NO_x的超净排放,应适当控制锅炉运行参数避免N_2O的生成。     

Pt–Ru–Co catalysts for PEMFC synthesized by combustion

In this work the novel use of urea combustion synthesis as a straightforward method for the preparation of a trimetallic alloy, 60 Pt–30 Ru–10 Co (mol%) is described. A novel composition in the Pt–Ru–Co ternary system has been considered for a possible substitution of commercial anode catalysts in PEMFC. The specific surface area (102 m²/g) of the carbon supported catalysts produces anodes which gave power density stable values of 260 mW/cm². The XPS (X-ray Photoelectron Spectrometry) data showed that combustion synthesis produces Platinum and Cobalt segregated in the catalyst’s surface, these metals are layered structured and exhibit different oxidation states.     

Catalytic combustion of chlorobenzene on modified LaMnO3 catalysts

Modified LaMnO₃ catalysts with perovskite structure prepared by co-precipitation method were tested in catalytic combustion of chlorobenzene. Characterizations show that the substitutions of different elements for Mn and La species affect significantly surface active oxygen species, H₂ consumption and the ratio of surface oxygen to lattice oxygen of LaMnO₃ catalysts. TOF_SA of LaMnO₃ catalysts is almost proportional to oxygen mobility. LSMO catalyst (substituted by Sr for La) with the largest oxygen mobility presents the highest stable activity which is ascribed to quickly remove the Cl species adsorbed on the surface of catalysts.     

Methane Combustion Over Copper Chromites Catalysts Prepared by the Sol–Gel Process

Abstract  

Methane combustion was performed over a series of copper chromites (CuCr₂O₄) catalysts prepared by the sol–gel process (SG). The results were compared with those obtained over commercial CuCr₂O₄. The samples were characterised by elemental analysis, thermal analysis, X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The as-synthesised CuCr₂O₄ sample exhibited higher specific surface area (248 m² g⁻¹) with respect to commercial solids (42 m² g⁻¹). The surface properties were established using XPS. Simultaneously, an increase in the atomic Cr⁶⁺/Cr³⁺ ratio (0.56 for SG catalyst vs. 0.39 for commercial sample) and a decreasing surface copper concentration (8.3%, for SG specimen vs. 17.6% for commercial catalyst) are observed. XPS study revealed also that Cu²⁺/(Cu° + Cu⁺) ratio of copper species remained constant (ca. 5) in both catalysts. Structure transformations of CuCr₂O₄ under reduction-reoxidation conditions showed that the reduction of copper and/or chromium cations from the CuCr₂O₄ and from delafossite (CuCrO₂) structure (CuCr₂O₄↔CuCrO₂ + Cu + Cr₂O₃↔Cu + Cr₂O₃) were different. This has lead to a difference in catalytic properties of the catalysts. Catalytic activity of SG catalysts was superior to that of commercial CuCr₂O₄ tested under the same conditions. Complex hysteresis behaviour for CuCr₂O₄ catalysts ramped over a temperature range of 220–850 °C where the stables active phases were obtained only after the first ramp of heating under reactants. No catalysts deactivation was further observed after several cycles of heating and cooling. The stabilisation of catalytic activity was attributed to the formation of mixed crystalline phases containing both copper and chromium species.     

Effect of chlorine compounds on the deactivation of platinum catalysts

A commercial platinum (Pt) catalyst with 0.15% platinum ingredient (referred to as Pt-O) was investigated for activity in the combustion of chlororganic compounds, for resistance to poisoning, and for potential application to control gas emissions. Investigations were also carried out on six other catalysts. These were platinum catalysts with platinum contents varying from 0.05% to 0.15% and platinum catalysts with palladium or manganese as active ingredients. The catalysts were tested in the oxidation of a chlorobenzene-xylene mixture to determine their poisoning resistance. The presence of manganese was found to have a disadvantageous influence on the combustion of chlororganics.     

高硅铝比小晶粒NaY分子筛/高岭土复合物的合成及其催化裂化性能

以两种不同粒径的高岭土为原料,采用水热法合成了高硅铝比小晶粒NaY分子筛/高岭土复合物,通过XRD、SEM、晶粒度分析和N₂物理吸附等表征手段对复合物进行了结构和形貌表征。结果表明,与商品NaY相比,高岭土合成样品的结构稳定性和水热稳定性显著提高,以细化高岭土为原料合成样品的晶粒尺寸达310 nm,比表面积达807 m²·g^-1。以改性NaY分子筛/高岭土复合物为活性组分制备了催化裂化催化剂,采用NH₃程序升温脱附(NH₃-TPD)技术对其酸性特征进行了分析,并在小型微反装置上对其重油催化裂化性能进行了评价。研究结果发现,随着骨架硅铝比增大,催化剂表面酸中心强度增加,而酸量下降。采用细化高岭土合成的NaY分子筛/高岭土复合物的分子筛晶粒更小,催化剂酸中心数量以及催化裂化性能均大幅度提升。随着高温焙烧高岭土/偏高岭土质量比的增加,合成产物中的高岭土基质含量增加,催化剂表面酸中心强度下降。以原料高温焙烧高岭土/偏高岭土质量比为0.5,骨架硅铝比为6.1(摩尔比)的样品制备的催化剂,去柴重油转化率高达85.4%,同时有高达64.2%的汽油收率,表现出优异的重油催化裂化性能。