共查询到18条相似文献,搜索用时 140 毫秒
1.
高炉煤气脱硫是实现钢铁行业多工序全流程超低排放的关键。高炉煤气中主要含硫组分是羰基硫(COS),常用γ-Al 2O 3基催化剂水解脱除,但是其水解活性及抗氧能力有待提高。本工作采用浸渍法制备了添加Fe和La活性组分的催化剂,通过ICP,XRD和TPD等手段表征了催化剂的理化性质,并在固定床-气相色谱联用装置考察了空速、粒径对催化剂催化水解COS过程的扩散效应,研究了催化剂的理化性质与COS水解活性的构效关系以及O 2的作用机制。结果表明,催化剂在80℃,160 000h -1条件下,活性组分Fe和La的添加可明显提高γ-Al 2O 3基催化剂的碱性位点;同时,丰富的孔隙结构降低了内扩散阻力,增强了H 2S从催化剂表面到气相的传质。Fe/Al 2O 3催化剂在保持较高的水解活性的同时能够协同脱除H 2S,但是O 2的存在增强了H 2S的吸附及其与Fe的... 相似文献
2.
利用微型固定床反应装置对工业Fe-Mo预加氢脱硫催化剂进行加氢脱硫(HDS)评价,研究焦炉煤气中不同常量含碳原料组分(CH 4、C 2H 4、C 2H 6、CO、CO 2)对催化剂加氢活性、选择性以及积炭的影响,并采用红外碳硫分析仪、N 2吸附-脱附、Raman以及TPRS-MS对催化剂进行表征。结果表明:在N 2气氛下,COS、CS 2和C 4H 4S加氢转化由易到难顺序为:COS>CS 2>C 4H 4S,但COS加氢转化受含碳气氛影响最明显,致使焦炉煤气加氢脱硫中COS难以完全脱除;不同气氛对硫化物加氢选择性都会产生影响,其中C 2H 4气氛对选择性影响最明显,而对H 2S收率影响最明显的是CO 2和CO;不同含碳... 相似文献
3.
为满足黏胶纤维废气脱硫净化需求,设计开发复配型溶剂并进行优化。基于密度泛函理论,利用AIM拓扑分析和RDG分析研究活性组分与CS 2的相互作用机理,通过分子模拟计算不同活性组分与CS 2分子间相互作用,根据黏胶纤维废气组成特点,设计优化UDS溶剂,进一步在常压实验装置上考察其脱除黏胶纤维废气中CS 2和H 2S效果。分子模拟计算结果表明,哌嗪(PZ)、环丁砜(SUL)、聚乙二醇二甲醚(NHD)、二甲基亚砜(DMSO)4种活性组分与CS 2分子间均为弱相互作用,相互作用的强度顺序为PZ > SUL > NHD > DMSO。选取与CS 2具有较强结合能的活性组分作为提高CS 2溶解性能的溶剂组分。脱硫实验结果表明,在常压、吸收温度50℃、气液比500条件下,优化的UDS-F溶剂可将模拟黏胶纤维废气中CS 2含量由400mg/m 3脱除至79mg/m 3,脱除率较原UDS-A溶剂高出19个百分点,较甲基二乙醇胺高出65个百分点,表现出优异的脱除性能。同时,其再生贫液在循环使用过程中依旧能够保持较好的H 2S和CS 2净化效果。对其抗发泡性能和抗腐蚀性能进行考察,UDS-F溶剂表现出良好的抗发泡性能和抗腐蚀性能。 相似文献
4.
高炉煤气(BFG)作为炼铁过程中副产的可燃气体,具有明显的资源回收价值,但其同时存在热值低、成分复杂等问题。目前大多数研究集中在对羰基硫(COS)、硫化氢(H 2S)等有害成分的脱除,而鲜有对高炉煤气特征组分的研究或报道。研究者对高炉煤气特征组分的来源、生成路径等不明朗,导致在研究过程中忽略了煤气复杂组分的相互影响,很多技术在工业应用时问题频发。本文阐述并分析了高炉煤气特征组分的来源及生成路径,进而讨论了高炉煤气特征组分对脱硫过程的影响。高炉原料、燃料和空气在高温条件下经过复杂的化学反应,生成粉尘、N 2、O 2、CO、CO 2、H 2、CH 4、H 2O、HCl、HCN、硫化物等共同组成高炉荒煤气,荒煤气中的O 2、CO x、H 2、H 2O、HCl、硫化物等化学成分对COS转化或H 2S脱除过程产生影响,导致催化剂中毒或转化率下降。本文通过分析探讨特征组分在高炉煤气产生和脱硫净化过程中的相互作用及影响规律,为超低排放背景下高炉煤气的净化和资源化提供方向和参考。 相似文献
5.
碳材料本身对于H 2S的净化效果有限,通过将活性催化剂负载到活性炭上可以弥补碳材料脱除H 2S气体能力的不足。本文选用三种具有典型孔隙结构的碳材料:微孔活性碳纤维、中孔活性炭以及孔隙更大的单壁碳纳米管,等体积浸渍不同浓度的碳酸钠溶液制作负载活性材料的脱硫剂,应用固定床反应实验评价不同负载量下制得脱硫剂的脱硫性能,并对材料进行表征测试。经过对比,具有发达微孔结构的活性碳纤维材料整体上具有最佳的脱硫性能,且活性物质的负载量并不是越大越好。实验条件下,在出口逐渐检测到SO 2以及H 2S两种气体,其中SO 2气体出现较早。测定各类碳材料负载以及脱硫前后的表面pH,发现负载Na 2CO 3后材料表面pH得到大幅度提升,而脱硫后的材料表面pH均有不同程度的下降。 相似文献
6.
燃煤烟气中有机污染物的排放逐渐引起重视。锰铈(MnCe)基催化剂被认为是一种低温高效、低成本的可应用于燃煤烟气污染物脱除的催化剂。本文通过浸渍法制备了MnCe基催化剂,通过物理化学表征和烟气模拟台架实验,研究了MnCe基催化剂配比、反应工况、烟气复杂组分(H 2O、SO 2、NH 3、NO)以及典型污染物脱除过程(Hg 0和NO催化转化)对催化脱除烟气中邻二甲苯行为的影响和规律。实验结果表明,Mn和Ce摩尔比为6∶4时催化剂脱除邻二甲苯效率良好。反应空速和MnCe负载量在低温下对催化脱除效率影响显著。烟气中H 2O、SO 2、NH 3、NO等组分对催化产生抑制作用,但抑制程度与作用机理具有显著差异。MnCe基催化剂对烟气SCR脱硝与Hg 0催化氧化皆具有较高效率,且受烟气中邻二甲苯影响较小;但受SCR气氛与Hg 0抑制,邻二甲苯催化脱除反应效率明显降低。 相似文献
7.
高炉煤气脱硫是实现钢铁行业多工序全流程超低排放的关键。高炉煤气中主要有机硫组分是羰基硫(COS),常用γ-Al 2O 3基催化剂水解脱除,但是其抗氧性能有待提高。采用共沉淀法制备了Ti 0.5Al和K 0.2Ti 0.5Al催化剂,考察了催化剂在含氧气氛下的COS水解催化性能,并分析了氧体积分数对COS转化率和H 2S产率的影响规律。活性测试结果表明,Ti 0.5Al催化剂的初始COS转化率接近90%,随着反应时间增长效率逐渐降低至60%以下;K 0.2Ti 0.5Al催化剂在0.5% (体积分数) O 2的气氛下持续反应22 h后,其COS转化率仍可保持在93.44%。表征结果显示,催化剂失活后比表面积大幅减小,表面碱性显著减弱。此外,活性中心Al原子硫酸化是导致催化剂失活的主要原因,而硫酸盐的沉积为次要原因。原位红外结果表明,K的引入可显著减弱O 2在催化剂表面的吸附,并且阻断中间过渡物种的氧化,这是K提高催化剂抗氧性能的关键。 相似文献
8.
高炉煤气脱硫是实现钢铁行业多工序全流程超低排放的关键。高炉煤气中主要有机硫组分是羰基硫(COS),常用γ-Al 2O 3基催化剂水解脱除,但是其抗氧性能有待提高。采用共沉淀法制备了Ti 0.5Al和K 0.2Ti 0.5Al催化剂,考察了催化剂在含氧气氛下的COS水解催化性能,并分析了氧体积分数对COS转化率和H 2S产率的影响规律。活性测试结果表明,Ti 0.5Al催化剂的初始COS转化率接近90%,随着反应时间增长效率逐渐降低至60%以下;K 0.2Ti 0.5Al催化剂在0.5% (体积分数) O 2的气氛下持续反应22 h后,其COS转化率仍可保持在93.44%。表征结果显示,催化剂失活后比表面积大幅减小,表面碱性显著减弱。此外,活性中心Al原子硫酸化是导致催化剂失活的主要原因,而硫酸盐的沉积为次要原因。原位红外结果表明,K的引入可显著减弱O 2在催化剂表面的吸附,并且阻断中间过渡物种的氧化,这是K提高催化剂抗氧性能的关键。 相似文献
9.
工业生产中含硫废气的排放严重污染了大气环境并且危害人体健康,COS的水解脱除是处理含硫废气的有效手段之一。通过水热法合成GaAl(O)催化剂,并且通过XRD、SEM、BET、XPS等技术对其进行系统的表征,结果表明,Ga离子进入了Al 2O 3晶格内部,催化剂的表面具有碱性。性能测试结果表明,Ga的添加能够极大程度地提升催化剂的水解性能。考察反应温度、空速和水含量对COS催化水解性能的影响,在140℃之后,GaAl(O)催化剂的COS转化率和H 2S选择性都约保持100%,并且适当的水含量有助于COS转化率的提升,在低于180℃时,COS转化率在高空速下相对较低。在模拟工业生产的反应条件下考察催化剂的稳定性,GaAl(O)催化剂在24 h的测试中保持100%的COS转化率。 相似文献
10.
用共沉淀法制备了一系列Ce-Cu-Al-O复合金属氧化物吸附剂,用于低温下脱除CO 2气体中的微量H 2S。采用XRD、N 2物理吸附、SEM及XPS等手段对脱硫前后的吸附剂结构进行表征。研究了Ce含量、煅烧温度、气体空速、杂质气体及吸附温度对吸附剂脱除H 2S性能的影响。结果表明,Ce-Cu-Al-O系列吸附剂在40℃条件下可有效脱除CO 2气体中的H 2S,Ce含量为10%的吸附剂(10Ce-Cu-Al-O)具有最大H 2S穿透吸附量,为94.1mg/g。研究发现,引入CeO 2能有效改善CuO的分散性,提高吸附剂的比表面积和孔容。提高煅烧温度,较大空速均不利于吸附剂的脱硫效果;平衡气CO 2会抑制H 2S的吸附;吸附温度不高于100℃时,10Ce-Cu-Al-O的穿透吸附量随温度升高而增加且不会生成COS副产物。表征结果显示,硫化后吸附剂的组分团聚导致了比表面积和孔容降低。此外,失活后的脱硫剂可在100℃用空气再生。 相似文献
11.
H 2S and NH 3 are major contaminants in many synfuel process gas streams. The H 2S is frequently removed by dissociation and reaction in scrubbers using alkaline scrubbing liquids. Some of the NH 3 is removed by simple dissolution in the same unit; the remaining NH 3 can be removed in a second scrubber using a mildly acidic liquid. The first scrubbing stage in such a system is novel in that an acidic gas (H 2S) and a basic gas (NH 3) are absorbed simultaneously. In this paper, the interesting behavior of this simultaneous acid gas-basic gas scrubbing process is described and discussed. The percentage H 2S and NH 3, absorption as a function of the injected liquid pH, the liquid-to-gas ratio, and the NH 3 content of the gas stream have been determined. 相似文献
12.
将H 2S和CO 2混合酸气一步转化制合成气,既实现了二者无害化处理,又生产出合成气,是一条理想的废气资源化利用新路线。由于分子结构稳定,在常规条件下因受热力学平衡限制,二者转化率极低。而在低温等离子体中,H 2S和CO 2可被激发为高活性物种来参与反应。研究了具有不同Si/Al摩尔比的ZSM-5催化剂与低温等离子体结合实现H 2S-CO 2一步高选择性制合成气,显著提高了H 2S-CO 2转化性能。考察了ZSM-5催化剂中Si/Al比和低温等离子体放电条件等对反应的影响。其中,当Si/Al比为80时表现出最优催化性能,最高H 2和CO产率分别达到56.1%和10.0%。对常规条件和低温等离子体氛围下的不同ZSM-5催化剂上CO 2、H 2S、CO、H 2等化学吸脱附行为进行了对比研究,发现低温等离子体促进了催化剂对CO 2、H 2及CO分子的吸附活化,进而明显提升了H 2S和CO 2转化。 相似文献
13.
The direct synthesis of methanethiol, CH 3SH, from CO and H 2S was investigated using sulfided vanadium catalysts based on TiO 2 and Al 2O 3. These catalysts yield high activity and selectivity to methanethiol at an optimized temperature of 615 K. Carbonyl sulfide and hydrogen are predominant products below 615 K, whereas above this temperature methane becomes the preferred product. Methanethiol is formed by hydrogenation of COS, via surface thioformic acid and methylthiolate intermediates. Water produced in this reaction step is rapidly converted into CO 2 and H 2S by COS hydrolysis. Titania was found to be a good catalyst for methanethiol formation. The effect of vanadium addition was to increase CO and H2S conversion at the expense of methanethiol selectivity. High activities and selectivities to methanethiol were obtained using a sulfided vanadium catalyst supported on Al2O3. The TiO2, V2O5/TiO2 and V2O5/Al2O3 catalysts have been characterized by temperature programmed sulfidation (TPS). TPS profiles suggest a role of V2O5 in the sulfur exchange reactions taking place in the reaction network of H2S and CO. 相似文献
14.
Hydrogenating catalysts were prepared by inserting Ru into the pores of mesoporous Al-MCM-41 materials by selective adsorption of [Ru(NH 3) 6] 3+. Ru/support catalysts were obtained after reduction with H 2. The activities of these catalysts in hydrogenation reactions were compared to those of Ru/HY and Ru/SiO 2. The catalytic properties in the absence of sulfur were tested in benzene hydrogenation, and the intrinsic activities of all the catalysts (either supported on mesoporous materials or on zeolites) were identical. It was concluded from this result that the dispersion of the Ru metallic phase was similar for all these catalysts. These samples were tested in the tetralin hydrogenation in pure H 2 and in the presence of H 2S (330 ppm of H 2S in H 2). They were found to be much less active than the zeolite-supported catalysts in the presence of H 2S. It is proposed that the lower activity of the catalysts supported on mesoporous materials is either due to their milder acidity, as evidenced by NH 3-TPD, cumene cracking and pyridine desorption experiments, or to the localization of the Ru nanoparticles on alumina islands. 相似文献
15.
Zn–Ti-based sorbents promoted with cobalt and nickel additive were prepared by simple physical mixing of single oxides. Their capacities for removing H 2S and NH 3 simultaneously, emitted from coal gasifiers, were investigated in a micro-reactor at 1 atm and 650 °C. NH 3 within the fuel gases did not affect the sulfur removing capacity of the Zn–Ti-based sorbent. The additives, cobalt and nickel, were found to be active components in NH 3 decomposition as well as H 2S absorption, while major components such as ZnO and TiO 2 did not show any activity in the NH 3 decomposition reaction. NH 3 was decomposed over both oxide and sulfide forms of the additives, even though the NH 3 decomposition ability of their sulfides dramatically decreased in the presence of H 2 gas owing to the equilibrium limitation of NH 3 decomposition. In the case of oxide forms, cobalt oxide showed excellent NH 3 decomposition capacity regardless of H 2 concentrations, while the capacity of nickel oxide depended on the H 2 concentrations. 相似文献
16.
This review article deals with the development of sulfur recovery from the Claus process to H 2S selective oxidation. Governments are constantly tightening regulations to limit the emission of sulfur compounds into the air. This makes it necessary to constantly enhance the level of sulfur recovery from natural, refinery, or coal gasification geses, and many improvements in the Claus process have been introduced to this end. In this review, emphasis has been put on the mechanism of reactions occurring in most of the sulfur recovery units, reactions between H 2S and SO 2 or O 2 and side reactions such as hydrolysis of COS and CS 2 or sulfation of the catalyst. 相似文献
17.
The influence of SO 2, H 2S and COS in low concentrations on the deactivation of Pt/Rh/BaO/Al 2O 3 NO x storage catalysts was investigated. Different samples of the catalyst were exposed to synthetic gas mixtures mimicking lean/rich engine cycling in a mixed lean application at 400 °C. The lean gas mixture contained 8 vol.% O 2, 500 vol-ppm C 3H 6 and 400 vol-ppm NO balanced to 100 vol.% with Ar. The rich excursions were performed by switching off the oxygen supply. Sulphur, 25 vol-ppm of either SO 2, H 2S or COS, was added to the gas flow either during the lean, the rich or both periods. This procedure aimed at investigating the influence of the exposure conditions and therefore the lean and rich periods were kept equally long (5 min). In addition, thermodynamical calculations for the prevailing conditions were performed. It was concluded that all sulphur compounds investigated, i.e. SO2, H2S and COS, had similar, negative impact on the NOx storage ability of the catalyst and that they all showed increased deactivation rates during rich exposure compared to lean. During lean exposure, all sulphur carriers showed similar behaviour, while H2S and COS caused severe loss of noble metal activity during rich exposure. 相似文献
18.
The effect of H 2S on the rates of toluene hydrogenation of sulfided Mo, Ni, Ni---Mo and Ni---Mo---P/alumina catalysts has been determined at 6 MPa, 350°C over a large range of H 2S partial pressure. In those conditions, Ni/alumina is nearly inactive. For the three other catalysts, similar trends are found with in particular no effect of H 2S at high partial pressure. In the presence of NH 3, the effect of H 2S remains globally the same. 相似文献
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