高温煤气脱硫剂的研究进展

高温煤气净化脱硫技术可使发电效率提高,成本降低,流程简化,是许多国家非常重视的研发工作。可再生金属氧化物与硫化氢或其他硫化物的作用机理及其行为是高温煤气脱硫研究中的关键所在。在已有文献工作的基础上,对国内外高温煤气脱硫剂的研究进行了系统总结,着重介绍了含钙、锌、铁、铜和锰等金属氧化物脱硫剂的研究现状,认为研究重点应从性能单一的金属氧化物转向可耐高温的多功能复合金属氧化物,同时具有再生硫回收的特性。     

锰氧化物改性炭基铁酸锌吸附脱硫剂的制备及其表征

利用锰氧化物脱硫剂机械强度高,反应速率快的特性,对炭基铁酸锌进行改性。在超声波辅助下共沉淀法制备活性炭负载复合金属氧化物(Fe,Zn,Mn)脱硫剂。采用XRD、SEM-EDS及XPS分析手段进行表征,分析其晶型结构、分散度、孔隙结构及其表面元素结构分布。结果表明,负载型铁锌锰金属氧化物在500℃下煅烧后,ZFM(1∶2∶0.6)形成的物相有Zn Mn O3,(Zn,Mn)Fe2O4,几乎没有单一金属氧化物的特征峰出现,说明铁锰锌氧化物之间均能形成复合晶相,其晶粒粒径大小随温度的升高而增加。复合金属氧化物在活性炭上高度分散,且形成大量孔隙,且Mn以Mn3+,Mn4+存在。     

高温煤气金属脱硫剂的研究进展

煤的清洁转化利用符合中国的能源结构,高温煤气脱硫是提高能源利用率的关键技术。本文综述了单一金属氧化物和复合金属氧化物干法脱除H2S的研究进展,对比分析了单一金属氧化物在脱硫效率、使用温度和再生方面的优缺点,指出由于单一金属氧化物脱硫剂不能满足实际生产需要,因此兼有单一金属氧化物优点的复合金属脱硫剂成为未来研究方向。同时,论述了复合金属脱硫剂的制备原则、脱硫效率及再生等方面的研究状况。在此基础上,重点对铁酸锌和钛酸锌两种具有代表性的复合脱硫剂及其他复合金属脱硫剂进行了介绍。     

常温金属氧化物脱硫剂研究综述

对氧化锌、 氧化铜和氧化铁的脱硫机理进行阐述,分析了常温下单一金属氧化物脱硫剂在不同制备方法和工艺条件对脱硫性能的影响,单一金属氧化物常温下脱硫性能较差.复合型金属氧化物可以有效地增加反应活性,改善了脱硫剂在常温下的脱硫性能.负载型金属氧化物采用多孔材料为载体,提高了活性组分在其表面的分散性,缓解了脱硫剂表面出现闭孔或...     

高温煤气中羰基硫的加氢脱除研究进展

综述了加氢转化法脱除高温煤气中COS的研究现状,从加氢转化催化剂镍、钴、钼系,具有转化和吸收双功能的脱硫剂(钙系、锌系、铁系、锰系、复合金属氧化物)以及改性活性炭基催化剂等方面进行了分析,并对相应的脱硫反应条件控制和现存问题进行讨论,提出了改进措施。     

助剂对高温锰基脱硫剂脱硫性能的影响

脱硫剂中加入助剂不仅可以提高脱硫剂的耐久性和机械强度,还可以提高其化学稳定性.采用机械混合法制备了锰铜脱硫剂,通过XRD,SEM和BET等手段研究了助剂对脱硫剂的结构、物相及比表面积的影响.并在固定床反应器中考察了助剂对脱硫剂脱硫性能的影响.实验结果表明,活性组分锰铜摩尔比为9:1,黏结剂选用10%自制溶胶来代替矿物黏结剂制备得到的脱硫剂有较好的脱硫性能,脱硫精度最高可达8×10-6,硫容量可达33.1%.助剂的加入可以改善脱硫剂的脱硫性能.     

国内专利精选

正一种用于乙炔氢氯化的非汞催化剂:CN105251502A∥王小昌(新疆兵团现代绿色氯碱化工工程研究中心),公开日期:2016-01-20公开了一种用于乙炔氢氯化反应合成氯乙烯的非汞催化剂,载体为活性炭与金属氧化物组成的复合载体,活性组分为钴、锰、铜、锌、铋、钡、钾的至少一种。该非汞催化剂不仅具有活性炭载体和金属氧化物载体的双重性质,还表现出     

煤气净化中H2S干法脱除的研究进展

综述了活性炭、金属氧化物、复合金属氧化物和活性炭负载金属氧化物干法脱除H₂S的研究进展.分析了活性炭和单一金属氧化物在使用温度、脱硫效率和再生等方面的优缺点,指出复合金属氧化物和活性炭负载金属氧化物在使用温度、硫化效率和再生性能等方面都有很大改进,是应用前景广阔的脱硫剂.根据它们脱硫的原理和特点,结合半焦和活性炭性质上的相似性,对半焦负载金属氧化物制备脱硫剂的可行性进行了探讨.     

高温煤气脱硫剂再生性能研究进展

金属复合型脱硫剂已经成为高温煤气脱硫剂的研究重点,脱硫剂不仅要求具有良好的硫化能力,还必须易于再生,以达到多次循环使用及降低生产成本的目的。介绍了中高温煤气脱硫剂的再生性能的研究概况,包括:铁和锌系列脱硫剂、钙和铈系列脱硫剂、铜和锰系列脱硫剂。大量实验研究表明,脱硫剂的种类和再生工艺与其再生后的脱硫特性密切相关,再生结果是脱硫剂能否工业化应用的关键环节之一,在考察脱硫剂硫化特性的同时,必须注重脱硫剂再生特性的研究。     

高温煤气脱硫剂及再生特性研究

高温煤气净化是实现IGCC过程的关键环节，系统地介绍了国内外钙、锌、铜的锰系高温脱硫剂近年来的研究结果，同时结合脱硫剂再生的研究，分析了各种脱硫剂在高温脱硫过程中可能遇到的问题，探讨了各种脱硫剂的再生方法以及相应的尾气处理方案，最后对我国今后高温煤气脱硫剂研究开发提出了几点建议。     

气体中微量甲醛的脱除研究进展

主要阐述了去除甲醛气体的常用材料（吸附材料、催化氧化材料、光催化降解材料和生物技术材料）的研究进展,文中指出碳基材料、分子筛、有机金属骨架常常被用作吸附挥发性有机气体,它们具备丰富的孔道结构和较大的比表面积,碳基材料和分子筛表面存在大量丰富的基团能够有效地增大甲醛的吸附容量,提高甲醛的吸附效率;有机金属骨架表面的金属与甲醛结合成键,有效提高材料的化学吸附;以金属氧化物为载体的材料常被用作催化氧化甲醛分子,将甲醛分子转化为无毒性的二氧化碳和水;半导体材料TiO₂常被用作光催化降解材料去除甲醛;除此之外还有一些利用生物技术来去除甲醛气体。本文对比了不同材料去除甲醛的优劣性,对不同的去除材料改性研究进行了归纳总结。     

Nanosized iron and iron–cobalt spinel oxides as catalysts for methanol decomposition

Nanosized iron and mixed iron–cobalt oxides supported on activated carbon materials and their bulk analogues prepared by thermal synthesis are studied by X-rays diffraction, Mössbauer spectroscopy, magnetic measurements and temperature programmed reduction. Their catalytic behavior in methanol decomposition to H₂, CO and methane is tested. Phase transformations in the metal oxides affected by the reaction medium are also investigated. Changes in the reaction mechanism of the methanol decomposition after the metal oxides deposition on the support as compared to the bulk phases are discussed.     

Sequential Combination of Constituent Oxides in the Synthesis of Pb(Fe1/2Nb1/2)O3by Mechanical Activation

Pb(Fe_1/2Nb_1/2)O₃(PFN) has been successfully synthesized via a novel mechanical activation of mixed oxides and columbite precursor consisting of lead oxide and FeNbO₄. A nanocrystalline perovskite phase 5–15 nm in crystallite size was formed after 30 h of mechanical activation at room temperature for both types of starting materials. However, the nanocrystalline PFN phase derived from the mixed oxides of PbO, Fe₂O₃, and Nb₂O₅is unstable, and develops pyrochlore phases when calcined at 500°–900°C, while no pyrochlore phase is observed for the material derived from the columbite precursor consisting of PbO and FeNbO₅. Different sintering behavior and dielectric properties were also observed between the two types of PFN. These differences are accounted for by the compositional inhomogeneity in the material derived from the mixed oxides, as was revealed by Raman spectroscopic studies. This suggests that mechanical activation is analogous to thermal activation, where the phase development is strongly dependent on the sequence of combining the constituent oxides.     

高性能碳基储能材料的设计、合成与应用

电化学储能器件的性能很大程度上决定于其电极材料。碳材料具有来源广泛、化学稳定性好、易于调控、环境友好等优点,被广泛应用于各类能量存储系统,但仍存在能量密度低、倍率性能差等问题。本文从碳材料孔结构调控、杂原子掺杂、与金属氧化物复合三个角度,综述了构建高性能碳基储能材料的设计合成策略,介绍了其在锂/钠离子二次电池、超级电容器等领域的研究进展,对几种方法策略的优缺点进行了总结,并对未来的研究方向进行了展望。本文对高性能碳基储能电极材料的设计开发具有积极意义。     

Thermal ageing of Pt on low-surface-area CeO2–ZrO2–La2O3 mixed oxides: Effect on the OSC performance

This work aims at exploring the thermal ageing mechanism of Pt on ceria-based mixed oxides and the corresponding effect on the oxygen storage capacity (OSC) performance of the support material. Pt was supported on low-surface-area CeO₂–ZrO₂–La₂O₃ mixed oxides (CK) by impregnation method and subsequently calcined in static air at 500, 700 and 900 °C, respectively. The evolutions of textural, microstructural and redox properties of catalysts after the thermal treatments were identified by means of X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (TPR) and high-resolution transmission electron microscope (HRTEM). The results reveal that, besides the sintering of Pt, encapsulation of metal by the mixed oxides occurs at the calcination temperature of 700 °C and above. The burial of Pt crystallites by support particles is proposed as a potential mechanism for the encapsulation. Further, the HRTEM images show that the distortion of the mixed oxides lattice and other crystal defects are distributed at the metal/oxides interface, probably indicating the interdiffusion/interaction between the metal and mixed oxide. In this way, encapsulation of Pt is capable to promote the formation of Ce³⁺ or oxygen vacancy on the surface and in the bulk of support. The OSC results show that the reducibility and oxygen release behavior of catalysts are related to both the metal dispersion and metal/oxides interface, and the latter seems to be more crucial for those supported on low-surface-area mixed oxides. Judging by the dynamic oxygen storage capacity (DOSC), oxygen storage capacity complete (OSCC) and oxygen releasing rate, the catalyst calcined at 700 °C shows the best OSC performance. This evident promotion of OSC performance is believed to benefit from the partial encapsulation of Pt species, which leads to the increment of Ce³⁺ or oxygen vacancies both on the surface and in the bulk of oxides despite a loss of chemisorption sites on the surface of metal particles.     

Decomposition of N2O on Perovskite-Related Oxides

Mixed metal oxides crystalizing in a perovskite-related structure have long been of interest to solid state chemists and physicists because of their technologically important physical properties. The ready availability of a family of isomorphic solids with controllable physical properties makes these oxides suitable for basic research in catalysis. These mixed metal oxides are more advantageous and are better catalytic materials than simple oxides because: (i) the crystal structure can accomodate various metal ions and can stabilize unusual and mixed valence states of active metal ion; (ii) appropriate formulation of these oxides leads to easy tailoring of many desirable properties such as valence state of transition metal ion, distance between active sites, binding energy, diffusion of oxygen in the lattice, magnetic and conducting properties of the solid; (iii) the catalytic activity can be correlated to solid state properties since many of their solid state properties are thoroughly understood; (iv) the surface of these oxides can be regenerated by suitable activation procedure.     

Decomposition of N2O on Perovskite-Related Oxides

Mixed metal oxides crystalizing in a perovskite-related structure have long been of interest to solid state chemists and physicists because of their technologically important physical properties. The ready availability of a family of isomorphic solids with controllable physical properties makes these oxides suitable for basic research in catalysis. These mixed metal oxides are more advantageous and are better catalytic materials than simple oxides because: (i) the crystal structure can accomodate various metal ions and can stabilize unusual and mixed valence states of active metal ion; (ii) appropriate formulation of these oxides leads to easy tailoring of many desirable properties such as valence state of transition metal ion, distance between active sites, binding energy, diffusion of oxygen in the lattice, magnetic and conducting properties of the solid; (iii) the catalytic activity can be correlated to solid state properties since many of their solid state properties are thoroughly understood; (iv) the surface of these oxides can be regenerated by suitable activation procedure.     

二氧化碳捕集材料的研究进展

二氧化碳过度排放所导致的全球变暖已成为环境危机的重要问题,所以中国提出的实现碳达峰和碳中和的战略目标势在必行.为了解决这个问题,科研工作者们采用多种多样的二氧化碳捕集和储存技术.该文重点介绍了碳类材料、沸石、金属有机骨架材料、水滑石类材料、金属氧化物及其盐以及负载胺基材料等主要的CO2吸附材料的最新研究进展,详细介绍了各种吸附剂的吸附机理、性能的优缺点、改进的方向以及面临的挑战,并对吸附材料未来发展方向进行了展望.     

炭基材料催化剂在烟气脱硫脱硝中的应用

炭基材料催化剂由于其化学稳定性良好、比表面积大、热导性能优良和吸附量大而被用于广泛的用于烟气脱硫脱硝催化剂的研制中。首先本文从炭基材料本身的结构特性出发,概述炭基材料本身作为催化剂进行烟气脱硫脱硝的原理,其次总结了在炭基材料表面负载各种金属氧化物后对烟气脱硫脱硝中的影响,最后对炭基材料催化剂的发展前景进行了展望。     

NOx低温选择性催化还原催化剂研究进展

催化剂是选择性催化还原脱硝技术的核心,其催化性能直接关系到脱硝效果的好坏。本文介绍了该领域新开发的贵金属、金属氧化物、分子筛、碳基催化剂等低温脱硝体系及其最新研究进展。对碳纳米材料催化剂和新型杂多酸催化剂等新成果作了介绍,并且对今后的研究方向作了展望。