矿物材料的添加对V-Mo/Ti平板式脱硝催化剂性能的影响

为增强V-Mo/Ti平板式脱硝催化剂的耐磨强度,在催化剂制备过程中添加矿物材料作为粘结剂。采用XRD、N_2-吸附脱附、SEM、H_2-TPR、拉曼光谱、XPS、NH_3-TPD等手段对催化剂进行表征。结果表明,3种矿物材料的添加均能有效提升催化剂的耐磨强度。凹凸棒土和硅藻土可以增加催化剂的比表面积,提升催化剂的还原性能,海泡石则与之相反。此外,添加矿物材料后,催化剂的酸性有不同程度的降低。3种矿物材料中,凹凸棒土对催化剂机械性能、脱硝性能均有提升作用,是合适的工业平板式脱硝催化剂粘结剂。     

添加硅溶胶对平板式脱硝催化剂性能的影响

采用硅溶胶作为粘结剂制备VMo/Ti平板式脱硝催化剂,考察了硅溶胶的添加对催化剂物化性能和脱硝性能的影响。结果表明,硅溶胶的添加可以提升催化剂的耐磨性能,增加催化剂的比表面积,促进活性组分的分散。然而硅溶胶同时也降低了催化剂的还原性能和酸性性能,对催化剂的脱硝性能有不利影响。相比之下,VMo/Si(5)-Ti是较为合适的工业催化剂配方。     

海泡石纤维在平板式脱硝催化剂中的应用

海泡石纤维是一种常见的矿物材料,已在工业领域有较多应用.制备一系列不同含量的海泡石纤维V-Mo/Ti平板式脱硝催化剂,考察海泡石纤维的添加对平板式催化剂的影响.采用X射线荧光光谱分析仪、X射线衍射仪、扫描电子显微镜、N2-吸附脱附、H2-TPR和NH3-TPD对催化剂进行表征.通过固定床微型反应器,对不同催化剂脱硝效率...     

平板式烟气脱硝催化剂耐磨强度检测技术研究

选择性催化还原法脱硝是国际上应用最广泛的、技术最成熟的烟气脱硝技术之一,其技术核心在于使用了脱硝催化剂,平板式脱硝催化剂是其中一种重要类型。脱硝催化剂的耐磨强度是影响其使用寿命的重要因素,尤其是对于高尘燃煤电厂来说,这一技术指标至关重要,其检测技术会直接影响耐磨强度指标的准确性。     

平板式脱硝催化剂煅烧过程中温度的测量方法

平板式脱硝催化剂煅烧工艺中温度的变化对催化剂产品最终的物理性能和化学性能有着重要的影响,因此很有必要对平板式脱硝催化剂煅烧过程中的温度进行测量研究,结合平板式脱硝催化剂生产工艺的特点,利用炉温跟踪测量系统对平板式脱硝催化剂煅烧过程中的温度开展了测量。     

凹凸棒土复合材料在催化领域的应用现状

凹凸棒土作为一种非金属矿物材料,储量丰富,结构特殊,具有良好的吸附性能和催化性能,常用作催化剂或催化剂载体。为了更好地了解并充分利用凹凸棒土资源,概括介绍了凹凸棒土的基本性质及包括酸改性、碱改性在内的不同改性方法对凹凸棒土自身性质的影响,主要叙述了凹凸棒土复合材料在光催化、气相催化、电催化及其他催化领域的应用现状。通过对比发现,凹凸棒土复合材料在各催化领域尤其是光催化领域应用价值较高。最后,对该复合材料在光催化治理废水污染物中所具有的优势和发展前景进行了总结和展望。     

白云石质凹凸棒土负载Fe的NH3-SCR脱硝性能研究

以白云石质凹凸棒土(DPC)作为低温选择性催化还原(SCR)脱硝催化剂载体,采用浸渍法在Fe基脱硝催化剂进行脱硝活性测试,并利用BET、XRD、XPS等手段对典型样品进行表征分析。研究结果表明:在负载Fe后催化剂中高温段脱硝活性有了较大的提升,Fe的最佳负载量为10%,300℃以上脱硝效率都达到92%以上;分析表明,负载Fe后,白云石等结构得到破坏,并使得催化剂中各组分高度分散,催化剂中Fe3+和Fe2+共同存在,极大提高催化剂高温的脱硝活性。     

Mo对平板式V-Mo/Ti脱硝催化剂活性及SO2氧化性能的影响

在工业脱硝催化剂生产线上制备不同MoO₃含量的V-Mo/Ti脱硝催化剂，通过XRF、XRD、N₂吸附-脱附、Raman、H₂-TPR、NH₃-TPD、SO₂-TPD、TG和耐磨强度对催化剂物化性质进行分析。在固定床反应器中考察催化剂的脱硝活性，并研究MoO₃含量对催化剂SO₂氧化性能的影响。结果表明，提高催化剂中MoO₃含量，对催化剂的晶型、孔结构影响较小，对催化剂单板的机械性能有一定的负面影响。相比V-Mo(3)/Ti催化剂，V-Mo(5)/Ti催化剂的酸性变化不大，还原性能提升，具有更好的脱硝活性。当MoO₃含量达到质量分数6.98%时，催化剂的总酸量明显降低，导致脱硝活性下降。提高催化剂中MoO₃含量造成脱硝反应过程中副产物N₂O生成量的增加，但较高的MoO₃含量可以有效减少催化剂对SO₂的吸附，减...     

天然矿物粉体填充聚乳酸复合材料的摩擦学性能

以干燥后的聚乳酸(PLA)作基体材料,将绢云母、蒙脱土、高岭土、硅藻土、滑石粉与凹凸棒六种矿物粉体通过加热共混的方法添加到PLA中,然后加工成测试试样,接着测试试样的减摩与抗磨性能。结果显示:在采用的测试条件下,绢云母在六种矿物粉体中具有最好的减摩抗磨性能,是一种适宜的PLA润滑改性填充材料;随着添加量的增加,绢云母的减摩抗磨性能呈现先上升后下降的趋势,添加量在3%时减摩性能相对较好,添加量在4%时耐磨性能较好。     

基于凹凸棒土催化双氧水分解的低温燃煤烟气脱硝

采用凹凸棒土为催化剂,在自主设计的固定床实验台上进行模拟燃煤烟气脱硝实验研究。考察了H_2O_2浓度、H_2O_2汽化温度、催化反应温度以及催化反应时间对催化脱硝性能的影响,分析了催化氧化反应后的液相成分。通过X射线荧光光谱(XRF)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、BET比表面积测定等分析方法对不同反应时间凹凸棒土催化剂的理化结构特性进行表征。脱硝实验结果表明,在H_2O_2溶液浓度为4mol/L、流量为5mL/h条件下,NO脱除效率达到70%,NO脱除效率随着催化反应温度的升高先升高后降低,随H_2O_2浓度和H_2O_2汽化温度的增加而升高。离子色谱(IC)分析结果说明,NO被氧化后得到的液相成分主要为硝酸。结合上述实验结果可知,·OH氧化NO是脱除烟气中NO的主要作用机制。表征结果表明:不同反应时间下凹凸棒土催化剂的结构、成分、孔结构参数等基本保持不变。在4h反应时间内,NO脱除效率基本保持不变,这与催化剂表征结果相一致,说明凹凸棒土作为催化剂具有良好稳定性。     

一种新催化体系的构建及其催化活性研究

用一种配体(5,5,7,12,12,14-六甲基-1,4,8,11-四氮杂环十四烷-N'-乙酸)和镧离子(Ⅲ)构建了一种新的催化体系,并用于催化对硝基苯酚磷酸二酯(BNPP)水解裂解。利用紫外-可见分光光度法研究了BNPP的催化水解的动力学。实验结果表明:这种新催化体系与其他相似的镧离子体系相比表现出更高的活性、水溶性和稳定性,在这一体系作用下,BNPP催化水解的速率比其自水解的速率提高了107倍左右。光谱分析表明,催化体系的活性物种是由镧离子和配体构成的大环配合物。     

The catalytic heat exchanger using catalytic fin tubes

The characteristics of a catalytic heat exchanger which integrates heat generation and heat exchange into one equipment have been investigated by the experiment and numerical simulation. The surface of the fin tubes was catalyzed by the formation of the oxide layer and the subsequent washcoating of ZrO₂, followed by the impregnation of Pd catalyst. The experimental results showed that the performance of catalytic combustion in the catalytic heat exchanger was more significantly affected by the inlet velocity of the mixture than by its inlet temperature and equivalence ratio. It was also found that the catalytic surface area was a critical parameter to obtain the complete conversion of the mixture. Numerical simulation has been performed with a commercial software FLUENT. The calculated results indicated that the performance of the catalytic combustion was influenced by the catalytic fin configuration as well as the flow pattern of the mixture over the catalytic fins. The results recommend that the number and thickness of catalytic fins should be designed above 6 pieces/inch and less than to achieve the best performance in the catalytic heat exchanger.     

乙炔氢氯化制备氯乙烯的非汞催化技术研究

介绍了非汞催化乙炔氢氯化制备氯乙烯的研究状况、催化剂性能、反应技术等,并指出了今后非汞催化乙炔氢氯化制备氯乙烯的研究重点和研究方向。     

催化型多孔陶瓷球制备及催化玉米秸秆热解

针对生物质热解液化过程中生物油品质差的问题,本文以陶瓷球作热载体为研究基础,制备了5种负载金属氧化物（ZnO、NiO、CeO₂、Cr₂O₃、Fe₂O₃）的多孔陶瓷球,在固定床反应器上研究多孔陶瓷球催化剂对玉米秸秆热解过程的催化效果。结果表明：多孔陶瓷球基体在热解过程中有一定催化活性,经浸渍改性处理后,都能促进生物油产率的提高,其中Ni基多孔陶瓷球热解的产率高达41.62%。多孔陶瓷球负载的5种金属氧化物可促使生物油中酚类、呋喃类物质的含量明显增加,酸类物质的含量明显降低,且种类减少,其中CeO₂降酸效果显著,降低幅度为37.15%。此外,催化型多孔陶瓷球的引入促进了不可冷凝气中C _n H _m （n≥2）的生成,烯烃类中乙烯的增长幅度最大,为50.53%,同时生物炭的理化特性在一定程度上得到改善和提高。     

Axial characterization of catalytic activity in close-coupled lightoff and underfloor catalytic converters

A exhaust system consisting of a close-coupled Pd technology 32 in³ lightoff converter and Pt/Rh technology 170 in³ underfloor converter was vehicle-aged for 56000 miles on a vehicle equipped with a 3.8 l engine. Following this aging, the converters were taken off the vehicle and cut into 1″ thick sections along their axis and characterized for lightoff and warmed-up activity using a laboratory reactor to simulate vehicle exhaust. Each section was also analyzed for the quantity of oil additive poisons (phosphorus and zinc) deposited. Following this initial characterization, the phosphorus and zinc deposits were removed, and the sections were characterized again for lightoff and warmed-up activity. This procedure was used to qualitatively determine the relative contribution of oil additive poisoning and thermal sintering to the total activity deterioration as a function of axial position in the catalyst monoliths.

Analysis of the lightoff converter as taken from the vehicle showed a dramatic axial gradient in the lean and stoichiometric lightoff and warmed-up (600°C) performance for HC, CO and NO_x, with most of the deterioration having taken place in the forward-most 1″ section of the converter, which was consistent with the gradient in the deposition of phosphorus (P) and zinc (Zn) in this converter. Comparison of these data sets with those obtained after removal of the P and Zn poisons indicates that most of the total deterioration of lean HC and CO activity can be attributed to P and Zn poisoning of the forwardmost 1″ section. When tested under stoichiometric conditions, most of the deterioration of HC activity is attributable to P and Zn poisoning, while most of the deterioration of CO and NO_x activity is attributable to thermal deterioration. A similar activity and poison deposition gradient was detected in the underfloor converter, but to a smaller extent.     

催化燃烧与催化剂材料在VOCs治理方面研究进展

介绍了VOCs对人类环境和健康造成的危害。概述了工业应用中常用于治理有机废气的催化燃烧技术的基本原理、特点及相关催化剂的研究现状，指出此类催化剂应朝着提高低温活性、热稳定性、抗毒能力和价格低廉的方向发展。     

催化裂化汽油催化氧化及萃取脱硫的研究

以分子氧为氧化剂,将催化氧化与萃取分离相结合,开展催化汽油氧化萃取脱硫研究。结果表明,与直接萃取相比,汽油经过氧化及溶剂萃取,汽油脱硫率有所提高,并且随着氧化温度的提高而增大,氧化过程对催化汽油脱硫有贡献。催化剂能够加速硫化物氧化反应,几种催化剂的汽油脱硫率从大到小顺序为：氧化铈＞碳酸锰或四硼酸钠或氧化锌＞硼酸或过硼酸钠。使用氧化锌或碳酸锰催化剂时,随着催化剂用量的增加,汽油脱硫率总体呈现降低的变化趋势。以硼酸为催化剂时,脱硫率随着催化剂用量的增加先增加后降低,认为催化汽油中硫化物的氧化反应符合连串反应机制。     

Other catalytic properties

The behavior of fresh and aged EUROCAT V₂O₅–WO₃/TiO₂ SCR catalysts in the (I) oxidative dehydrogenation of light alkanes, and conversion of (ii) propan-2-ol, (iii) NO in the presence of propene and oxygen, (iv) propane and propene and (v) chloropropane is reported to analyse possible modifications of the catalyst properties during use and give a more comprehensive general picture of its surface and reactivity properties.     

Selection of metalloenzymes by catalytic activity using phage display and catalytic elution

The metallo-beta-lactamase betaLII from Bacillus cereus 569/H/9 was displayed on the filamentous phage fd. The phage-bound enzyme fd-betaLII was shown to be active on benzylpenicillin as substrate; it could be inactivated by complexation of the essential zinc(II) ion with EDTA and reactivated by addition of a zinc(II) salt. A selection process was designed to extract active phage-bound enzymes from libraries of mutants in three steps: 1. inactivation of active phage-bound enzymes by metal ion complexation, 2. binding to substrate-coated magnetic beads, 3. release of phages capable of transforming the substrate into product upon zinc salt addition. The selection process was first successfully tested on model mixtures containing fd-betaLII plus either a dummy phage, a phage displaying an inactive mutant of the serine beta-lactamase TEM-1, or inactive and low-activity mutants of betaLII. The selection was then applied to extract active phage-bound enzymes from a library of mutants generated by mutagenic polymerase chain reaction (PCR). The activity of the library was shown to increase 60-fold after two rounds of selection. Eleven clones from the second round were randomly picked for sequencing and to characterize their activity and stability.