NOx储存-还原催化净化技术研究进展

从NOx储存-还原催化剂活性组分、NOx吸附储存材料、载体及助剂、反应机理以及催化剂失活等方面评述了NOx储存-还原催化净化技术近年来的研究进展。指出硫中毒和热劣化是催化剂失活的主要原因,添加少量过渡金属或稀土金属是改善催化剂的热稳定性和抗硫能力,延长催化剂使用寿命,降低催化剂成本的有效途径;原位傅里叶变换红外光谱技术成为研究NOx储存-还原反应及硫中毒失活机理的有效手段。     

选择性催化还原NOx催化剂的研究进展

综述了选择性催化还原法脱除NOx的各类催化剂,包括贵金属、分子筛、金属氧化物等。传统催化剂由于不能同时兼备优良的催化活性、热稳定性、抗中毒能力,因此难以真正实现商业化。由不同类型催化剂优化组合而成的复合型催化剂和NOx的存储一还原型催化剂克服了传统催化剂的上述缺点,在脱除NOx领域具有广阔的应用前景。     

NOx储存-还原催化净化技术研究进展

从NOx储存-还原催化剂活性组分、NOx吸附储存材料、载体及助剂、反应机理以及催化剂失活等方面评述了NOx储存-还原催化净化技术近年来的研究进展.指出硫中毒和热劣化是催化剂失活的主要原因,添加少量过渡金属或稀土金属是改善催化剂的热稳定性和抗硫能力,延长催化剂使用寿命,降低催化剂成本的有效途径;原位傅里叶变换红外光谱技术成为研究NOx储存-还原反应及硫中毒失活机理的有效手段.     

低温选择性催化还原催化剂抗SO2性能的研究进展

低温选择性催化还原法(SCR)是一种有潜力的烟气脱硝技术。针对低温SCR法目前存在的缺陷,综述了低温SCR催化剂受SO2毒害的作用机理,总结了催化剂组成成分、制备方法、硫酸化及还原剂种类等因素对低温SCR催化剂抗SO2性能的影响。为进一步开发出具备良好抗SO2性能的低温SCR催化剂提供一定的借鉴作用。     

还原消除NOx的几类催化剂

综述了几类新型的NOx消除（De-NOx)催化剂：活性炭催化剂、负载型贵金属（Pd、Pt、Ag等）、水滑石类化合物等,它们可有效应用于NOx的催化消除。     

碳烟颗粒在NOx储存催化剂上的燃烧研究进展

柴油车排放的碳烟颗粒和NOx严重危害环境和健康,开发和应用柴油车排放后处理技术势在必行。总结了尾气后处理技术中碳烟颗粒在NOx储存催化剂上燃烧的技术发展路线以及研究进展,包括几种不同贵金属型和稀土混合氧化物型催化剂,同时归纳了其催化作用机理,并对NOx物种对碳烟燃烧活性影响进行归纳分析,对该技术在实际应用中存在的问题和应用前景进行了讨论。     

NOx选择性催化还原处理技术的发展

介绍了不同还原剂催化还原NOx的反应机理、NOx处理技术的研究及工业现状，分析了NOx选择性催化还原的发展及应用前景。     

SO2-4/MxOy型固体酸催化剂改性的研究进展

阐述了近年来SO2-4/MxOy型固体酸催化剂的开发研究和应用现状.鉴于固体酸催化剂存在的问题,国内外对SO2-4/MxOy型催化剂进行了改性,在活性和选择性方面作了探讨.从理论上指导合成和制备各种高性能的固体酸催化剂,在应用研究上则根据工业化生产的要求提高使用寿命和拓展使用范围.     

锰钛系低温选择性催化还原催化剂的抗SO2和抗H2O性能研究进展

低温选择性催化还原（SCR）脱硝技术具有运行成本低、能耗低和布置方便的优点,催化剂的反应温度低,适合中小型工业锅炉的脱硝技术需求,因此受到越来越多的关注。锰钛系催化剂以其较高的低温脱硝效率成为当前低温SCR催化剂研究领域的热点,然而催化剂易受到SO₂和H₂O的影响,限制了它的工业应用。本文介绍了在含SO₂和H₂O的条件下锰钛系低温SCR催化剂的中毒症状,总结了催化剂的SO₂和H₂O中毒机制,重点阐述了在抗硫方面掺杂过渡金属元素以及载体改性的研究进展,详细介绍了掺杂Ce、Co、Fe和Ho等元素以及催化剂酸改性和复合载体对催化剂抗硫性的影响,同时简要总结了近年来其他方法提高锰钛系低温SCR催化剂抗硫抗水性能的状况,最后归纳了目前此类催化剂抗硫抗水措施的局限并指出今后的重点是进一步提高其抗中毒能力。     

SO2-4/MxOy型固体超强酸催化剂的研究进展

概述了SO2-4/Mx Oy 型固体超强酸催化剂的分类、制备方法及表征手段,详细说明了通过促进剂、催化剂载体及引入金属或离子等对SO2-4/ZrO2型固体超强酸改性方面的研究进展,指出目前在SO2-4/Mx Oy 型固体超强酸催化剂研究方面存在的问题,展望了SO2-4/Mx Oy 型固体超强酸催化剂的发展前景。     

NOx、SO2液相反应研究进展--一种同时脱硫脱氮的新思路

从烟气脱硫脱氮的角度讨论了NOχ与SO2在液相中的一系列反应,包括NO、SO2溶于水与SO3^2-、HSO3^-水溶液间的反应,更为重要的是通过研究SO2^-与HSO3^2-反应制备羟胺二磺酸盐、硫酸羟胺的过程,即生产尼龙66的中间体己内酰胺的必备原料,提出了一种有意义的脱硫脱氮新思路：利用NOχ的氧化性与SO2的还原性在水溶液中构造一自催化自氧化还原反应,并得到有用的工业原料硫酸羟胺。     

国外烟气同时脱硫脱氮技术研究现状

同时脱硫脱氮处理是我国烟气治理的发展方向,本文介绍了目前国外燃煤烟气同时脱硫脱氮技术研究的各种方法,并分析了其技术特点和发展前景,供参考。     

胺基CO2固体吸附剂脱碳特性及SO2的影响

燃煤电厂烟气中存在的微量SO₂对胺基CO₂固体吸附剂的碳酸化反应及循环特性有不利影响。利用固定床反应器,针对采用溶胶凝胶法制备的胺基CO₂固体吸附剂的碳酸化特性及其在含SO₂气氛下的失效规律进行了实验研究,并结合红外光谱、有机元素分析、BET等测试手段,研究其失效机理。结果表明,所制备的胺基CO₂固体吸附剂在反应温度50℃时具有较好的碳酸化反应特性和循环特性。当反应气氛中存在SO₂时,由于生成了不可再生的亚硫酸/硫酸盐类物质而导致胺基活性位损失,孔隙结构发生变化,影响了吸附剂的脱碳性能,但适当提高反应温度可提高吸附剂的碳酸化反应竞争性。     

Research progress in the SO2resistance of the catalysts for selective catalytic reduction of NOx

The selective catalytic reduction(SCR)of NOxwith NH3has been proven to be an efficient technology for NOx conversion to N2.However,the catalysts used for SCR usually suffer from the problem of sulfur poisoning which seriously limits their practical application.This review summarized sulfur poisoning mechanisms of various SCR deNOxcatalysts and strategies to reduce deactivation caused by SO2such as doping metals,control-ling the structures and morphologies of the catalysts,and selecting appropriate supports.The methods and procedures of catalysts preparation and the reaction conditions also have effect on SO2-resistance of the catalysts. Several novel catalyst systems that exhibited good SO2resistance are also introduced.This paper could provide guidance for the development of highly efficient sulfur-tolerant deNOxcatalysts.     

用于SO2氧化的V2O5-K2SO4/硅藻土工业催化剂失活原因探讨

本文采用X-射线衍射(XRD)、程序升温还原（TPR）及BET法比表面测定和扫描电镜（SEM）等手段,对两批用于SO₂工业氧化的V₂O₅-K₂SO₄/硅藻土催化剂(A和B)的物相结构、催化活性和比表面等进行了对比研究,探讨了催化剂B在工业生产中快速失活的原因。     

SO2-4/MnOm型固体超强酸性能的改进

SO2-4/MnOm型固体超强酸催化剂性能的改进,着重在于提高催化剂的催化活性和选择性.本文参考了国内外在该方面最新的文献,对SO2-4/MnOm型固体超强酸性能改进的方法进行了系统阐述.     

Catalytic reduction of SO2 with methane over molybdenum catalyst

This paper deals with catalytic reduction of SO₂ with methane using molybdenum sulfide catalyst supported on two different activated carbons (Darco TRS and Norit ROZ-3). The experiments evaluated the effects of MoS₂ catalyst loading (10%, 15%, and 20% Mo, by weight), gas feed-rate concentration ratios of CH₄ to SO₂ (CH₄: SO₂ ratios of 2: 1, 1: 1, and 1: 2) and reaction temperatures (450°C, 500°C, and 600°C). The reactivity of each catalyst was evaluated by three different parameters: (a) SO₂ conversion, (b) CH₄ conversion and (c) the yield of elemental sulfur. The results show that the catalytic activity of MoS₂ supported on activated carbons is strongly related to the reaction temperature and the CH₄ : SO₂ feed ratio, with a secondary dependency on the loading of the MoS₂. The 20% MoS₂ catalyst supported on Darco TRS in a reactor stream with CH₄ : SO₂ = 1 : 1 demonstrated the highest activity of all the catalysts tested, having an SO₂ conversion of 99·8%. At 600°C and with a CH₄ : SO₂ = 1 : 1, the catalysts with 20% loading supported on both Dacro TRS and Norit ROZ-3 exhibited comparable SO₂ conversion, both above 90%.     

Planar Models for Alumina-Based Catalysts

Planar transition aluminas are gaining attention as models for alumina-based catalysts [I] because of their attractiveness for study by modern surface analytical techniques [2], electron optical methods [3], and reflection spectroscopy [4–7]. In this context “planar” means a thin (<10–4 cm) flat oxide layer of uniform thickness. Conventional high surface area aluminas which are used commercially for adsorbents, catalysts, and catalyst supports usually require grinding and /or pressing into disks for characterization by these approaches. This can expose unwanted inner structures or expose the samples to potential contamination by the grinding and pressing tools or uncontrolled atmospheres. In addition, difficulties arise in attempting to study the various stages of alumina development involved with commercial methods since these entail sols, gels, powdered hydroxides, and other inconvenient structures.     

INTEGRATED TESTING OF THE NOXSO PROCESS: SIMULTANEOUS REMOVAL OF SO2 AND NOx FROM FLUE GAS

Parametric studies with the NOXSO process—a dry, regenerable flue gas treatment system that simultaneously removes SO₂ and NO_x from flue gas produced by the combustion of coal—were conducted. The reusable sorbent that was tested consisted of sodium carbonate impregnated on a high surface area γ-alumina sphere (1·6- mm nominal diameter). All process steps, including adsorption and regeneration, were integrated into a new 60-KW_e-scale Life-Cycle Test Unit so that continuous, long-term operation of the total process could be experimentally evaluated. The effects of sorbent flow rate, temperature, inlet SO₂ and NO_x, concentrations, and sorbent residence time (fluid bed depth) on pollutant removal efficiencies in the absorption step were determined. Also, the impact of the type of regenerant gas, temperature, steam, excess regenerant gas, and diluent on the regeneration of the sorbent was investigated. Sorbent properties with respect to time on stream (cycles of operation) are also reported.     

Ce掺杂对钒钨钛催化剂脱硝性能的影响

对钒钨钛（V-W-Ti）催化剂进行Ce掺杂改性制备了CexV1W7/Ti（x%为CeO2负载量）,通过XRD、TEM、FTIR、XPS等表征其结构和元素组成,通过NH3/NO-TPD表征NH3和NO在催化剂表面的吸附强弱分布,并测试不同CeO2负载量下催化剂的脱硝性能,最后经密度泛函理论(DFT )计算探究催化剂的失活机理。结果表明,负载CeO2增加了催化剂表面化学吸附氧的比例和Br?nsted酸性位点,但也减少了催化剂表面V4+的比例和Lewis酸性位点;适当CeO2负载量能显著提高钒钨钛催化剂的中低温活性,但负载量过多会降低催化剂的高温活性,CeO2负载量为1% （以催化剂质量分数为基准）的钒钨钛催化剂（Ce1V1W7/Ti）表现最佳,其在全温度（260~400 ℃）段的脱硝活性均优于改性前,在260 ℃,空速为6×104 h-1的反应条件下,NOx脱除率从79.0 1%增加至99.19%,在含有H2O、SO2的气氛中,其NOx脱除率从58.33%升至74.55%。Ce掺杂降低了催化剂表面的氧空位形成能,改变了催化剂表面的酸位强弱,强化了SO2在催化剂表面的吸附,SO2中毒后的催化剂表面会沉积硫酸铵盐,在H2O的协同作用下,Ce掺杂后催化剂表面更易沉积硫酸铵盐,这是催化剂失活的主要原因。