γ-Al2O3基催化剂上高炉煤气COS的水解活性研究

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-Al₂O₃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O₂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-Al₂O₃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H₂S从催化剂表面到气相的传质。Fe/Al₂O₃催化剂在保持较高的水解活性的同时能够协同脱除H₂S,但是O₂的存在增强了H₂S的吸附及其与Fe的...     

类水滑石衍生锌基氧化物高温煤气脱硫过程中COS释放行为及其抑制研究

高温煤气脱硫是煤炭清洁转化过程中的关键技术之一。前期研究表明,锌铝类水滑石基衍生氧化物可高效脱除高温煤气中的H₂S,但其脱硫过程中COS释放规律缺乏定性定量研究。探讨了类水滑石衍生锌基氧化物脱硫过程COS释放的可能途径,包括反应热力学分析及实验研究,提出采用镍掺杂策略以抑制脱硫剂脱硫过程中生成COS。研究表明,锌铝类水滑石基衍生氧化物脱除煤气中H₂S时产生COS的主要途径是H₂S与CO₂间的气固相催化反应,该途径所释放COS量占总释放量的78%。通过镍助剂的掺杂使得锌铝类水滑石基衍生氧化物既保持了原有结构形貌,也有效抑制了其脱硫过程中COS的释放;其中最佳镍掺杂量(Zn/Ni摩尔比为30)脱硫剂穿透前的COS释放量减少88%,而硫容仅降低1.5%。     

TiAl基羰基硫水解催化剂的中毒机制与抗氧性能研究

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-Al₂O₃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H₂S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） O₂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O₂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。     

TiAl基羰基硫水解催化剂的中毒机制与抗氧性能研究

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-Al₂O₃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H₂S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） O₂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O₂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。     

Ce-Cu-Al-O复合金属氧化物吸附剂低温脱除H2S

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CO₂气体中的微量H₂S。采用XRD、N₂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H₂S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CO₂气体中的H₂S,Ce含量为10%的吸附剂（10Ce-Cu-Al-O）具有最大H₂S穿透吸附量,为94.1mg/g。研究发现,引入CeO₂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CO₂会抑制H₂S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。     

焦炉煤气常量含碳气氛对加氢脱硫催化剂活性、选择性和积炭的影响

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(CH₄、C₂H₄、C₂H₆、CO、CO₂)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、N₂吸附-脱附、Raman以及TPRS-MS对催化剂进行表征。结果表明：在N₂气氛下，COS、CS₂和C₄H₄S加氢转化由易到难顺序为：COS>CS₂>C₄H₄S，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C₂H₄气氛对选择性影响最明显，而对H₂S收率影响最明显的是CO₂和CO；不同含碳...     

HCN、COS和CS2催化水解及其水解产物协同净化的研究进展

氰化氢（HCN）、羰基硫（COS）、二硫化碳（CS₂）广泛共存于黄磷尾气、焦炉煤气、碳一化工等化工行业废气中,目前大多数研究局限于3种气体的单独脱除,3种气体同时脱除的研究鲜有报道,而3种气体的协同脱除势在必行。催化水解法能够将HCN转化成NH₃,COS和CS₂水解成H₂S。NH₃和H₂S可以分别被催化氧化为N₂及S,S可以回收利用。一步法实现HCN、COS和CS₂的水解及水解产物NH₃和H₂S的催化氧化的催化剂开发是该技术的核心问题,本文针对近几年3种气体水解催化剂的相关研究成果进行了综述,包括负载型催化剂和非负载型催化剂,与此同时,针对水解产物NH₃和H₂S的催化氧化的协同净化技术进行了分析,旨在为后续3种气体同时催化水解及协同净化其水解产物催化剂的开发提供理论指导,为低温环境下协同催化水解HCN、COS和CS₂,并利用原料气中的氧一步法净化水解产物技术的未来发展及应用提供参考。     

低温甲醇工艺洗预洗甲醇增加过滤器技术方案研究

低温甲醇洗净化工艺是对粗煤气中的 HS₂、CO₂、杂质气体组分进行脱除,其工作原理为以低温甲醇有机溶剂为吸收剂,利用 CO₂、H₂S、COS 比 H₂、CO 在吸收剂中溶解度大的特性而除去,吸收后溶液的再生依靠简单的闪蒸解吸和气体放出 CO₂、H₂S 等。甲醇吸收酸性气体属物理吸收,气液平衡关系开始时符合亨利定律(P=KX),吸收剂的吸收容量随酸性组分分压的提高而增加,溶液循环量与原料气量及操作条件有关。采用低温甲醇洗工艺对粗煤气中的 HS₂、CO₂、COS 进行脱除,但受限于预洗甲醇含有大量的杂质,带入热再生塔后,这些杂质在热在生塔累积,导致热在生塔再生效果下降。本文通过研究低温甲醇工艺洗预洗甲醇增加过滤器技术方案研究,解决低温甲醇洗工艺在运行过程中甲醇排放量大能耗高的问题。     

活性碳纤维负载型脱硫剂在矿井气体环境条件下的应用

H₂S作为煤炭开采过程中经常会出现的气体,对煤矿的生产安全造成不利影响,必须进行脱除工作。然而煤矿中还可能存在其他组分的气体,这些气体可能会一定程度上影响H₂S的脱除。本文选取活性碳纤维分别负载氢氧化钠及氧化铜,并选取两种材料的最佳负载量。之后,模拟煤矿实际条件,探讨复合脱硫剂在实际矿井气氛条件下的脱硫性能。结果表明,煤体在受热情况下会产生的多组分混合性气体,这些气体会对脱硫剂性能产生极大的影响,当煤体温度升高,其产生的CO、CO₂等气体呈指数增大,并且会产生少量的CH₄、C₂H₆、C₂H₄、C₂H₂等气体,随着这些气体生成量增大,脱硫剂脱硫性能开始下降。且在矿井气体氛条件下SO₂气体的产生受到了抑制,特别在煤气组分含量大的情况下,SO₂气体甚至晚于H₂S气体出现。此外通过测量脱硫剂失活后的表面pH,发现即便在一些气体氛围下脱硫剂的脱硫时间更短,其脱硫后产物的表面pH极为相近,说明煤体产生的酸性气体CO以及CO₂等可能也被吸附到脱硫剂的表面上生成酸性物质。     

水蒸气对oxy-coal燃烧中NO生成的影响

为了研究H₂O对燃料N向NO转化各个阶段的影响,采用可沿程取样的沉降炉反应器,研究了一种烟煤在1273 K温度下,O₂/N₂、O₂/CO₂以及O₂/CO₂/H₂O气氛下燃烧的燃尽与NO生成的情况.并通过在停留时间为0.2、0.3、0.5、1.1 s与O₂浓度为5%、21%及30%情况下的实验来研究H₂O对NO生成的影响.实验结果表明,相对于O₂/CO₂气氛,H₂O的添加抑制了NO的生成,且该影响主要集中在燃烧初期挥发分N的氧化过程.随着O₂浓度的增加,H₂O添加对oxy-coal燃烧方式下NO生成影响加大.     

A thermodynamic study of the removal of HCl and H2S from syngas

Advanced integrated-gasification combined-cycle (IGCC) and integrated-gasification fuel cell (IFGC) systems require high-temperature sorbents that are capable of removing hydrogen chloride and hydrogen sulfide from coal derived gases to very low levels. HCl and H₂S are highly reactive, corrosive, and toxic gases that must be removed to meet stringent environmental regulations, to protect power generation equipment and to control the emissions of contaminants. The thermodynamic behavior of 13 sorbents for the removal of HCl and H₂S under various conditions including: initial toxic gas concentration (1–10000 ppm), operating pressure (0.1–11 Mpa), temperature (300 K–1500 K), and the presence of H₂O were investigated. The correlation between HCl and H₂S was also examined. Thermodynamic calculations were carried out for the reactions of the 13 sorbents using a FactSage 5.2 software package based on free energy minimization. The sorbents, Na₂CO₃, NaHCO₃, K₂CO₃, and CaO are capable of completely removing chlorine at high temperatures (up to ~1240 K) and at high pressures. Water vapor did not have any significant effects on the dechlorination capability of the sorbents. Nine of the sorbents namely; Cu₂O, Na₂CO₃, NaHCO₃, K₂CO₃, CaO, ZnO, MnO, FeO, and PbO, were determined to have great potential as desulfurization sorbents. Cu₂O and ZnO had the best performance in terms of the optimum operating temperature. The addition of water vapor to the reactant gas produces a slightly detrimental effect on most of the sorbents, but FeO exhibited the worst performance with a reduction in the maximum operating temperature of about 428 K. The dechlorination performance of the alkali sorbents was not affected by the presence of H₂S in the reactions. However, the desulfurization capability of some sorbents was greatly affected by the presence of HCl. Particularly, the performance of Cu₂O was significantly reduced when HCl was present, but the performance of FeO improved remarkably. The thermodynamic results gathered are valuable for the developments of better sorbents.     

不同烟气组分对粉状活性焦吸附汞的影响机理

在模拟燃煤热烟气为热源和介质条件下，以准东褐煤为原料，通过一维沉降炉进行炭化活化（一步法）制备粉状活性焦，考察了活性焦对Hg⁰的吸附能力，探索了SO₂、H₂O、O₂、CO₂、H₂O+O₂、SO₂+O₂及H₂O+SO₂+O₂气氛对活性焦吸附Hg⁰的影响机理。结果表明：一步法获得的活性焦对Hg⁰具有较高的吸附性能。N₂气氛作对比，H₂O、H₂O+O₂、CO₂和SO₂气氛下抑制活性焦对Hg⁰的吸附；O₂、SO₂+O₂和H₂O+SO₂+O₂促进活性焦对Hg⁰的吸附。通过Hg 4f的XPS分析证明了不同气氛组成对活性焦吸附Hg⁰的抑制和促进机理。H₂O覆盖在活性焦活性位上和堵塞孔隙而抑制活性焦对Hg⁰的吸附；SO₂与Hg⁰在活性焦上发生竞争吸附而抑制对Hg⁰的吸附；CO₂ 吸附在活性焦微孔上而抑制对Hg⁰的吸附；O₂气氛下主要形成了HgO, SO₂+O₂气氛下Hg⁰被氧化成HgSO₃，进一步氧化成HgSO₄； H₂O+SO₂+O₂气氛下，Hg⁰被氧化成HgO和HgSO₄。     

Investigations of sulphur deactivation of NOx storage catalysts: influence of sulphur carrier and exposure conditions

The influence of SO₂, H₂S and COS in low concentrations on the deactivation of Pt/Rh/BaO/Al₂O₃ 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.% O₂, 500 vol-ppm C₃H₆ 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 SO₂, H₂S 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 NO_x 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.     

相变吸收酸性气体的发展现状

酸性气体,如CO₂、SO₂和H₂S的过量排放已经造成温室效应或酸雨等一系列环境危害。传统的溶剂吸收法由于技术成熟、成本低廉而得到了广泛应用,但它依然存在吸收剂再生能耗高、产物附加值低的缺点。近年来,一种新的吸收方式,相变吸收（即均相体系在吸收酸性气体后分为两相,酸性气体主要富集于其中一相）,引起了人们的广泛关注。该法在吸收剂再生时只需要对其中的富相进行处理,从而减少了处理量,降低了解吸能耗,且富相中的酸性气体作为一种已经被改性的原料可以直接用于合成含硫或含碳化学品,从根本上避免再生过程。本文阐述了相变吸收的研究现状,依次对CO₂、SO₂以及H₂S体系作了详细的介绍。将相变吸收分为液-液相变、液-固相变两类,介绍了两种相变吸收的研究进展,并分析比较了它们优缺点。在实际使用中,不同领域应综合考虑。目前,相变吸收实现了吸收剂对SO₂气体的质量吸收量为1.56g SO₂ /g DMEA,对H₂S的为0.205g H₂S/ g DBN,对CO₂的摩尔吸收量为1.87mol CO₂/mol （TETA/PEG200）,与其他方法相比,相变吸收的吸收量非常高。这些结果表明相变吸收是一种极具潜力的酸性气体捕集方式。     

乙醇胺对介质阻挡耦合电晕放电同时脱除NO、SO2的影响

采用自行设计的介质阻挡耦合电晕放电等离子体反应装置进行了模拟烟气同时脱硫脱硝的研究,分别考察乙醇胺（HOCH₂CH₂NH₂,MEA）在不同模拟烟气体系中对NO、SO₂脱除的影响,深入探讨了MEA在放电过程中与NO的作用机理。结果表明：在N₂/O₂/SO₂/NO体系中,0.56% MEA的加入可以显著消除O₂对NO脱除的抑制作用;在N₂/CO₂/SO₂/NO体系中,MEA会吸收进入体系中的部分CO₂,以减弱CO₂对NO脱除的抑制;在N₂/O₂/CO₂/H₂O/NO/SO₂体系中,0.56% MEA的加入既可以有效减弱H₂O的影响,也可以使NO的脱除率达到71.28%,继续将MEA的体积分数增大至1.20%时,可将该体系下NO脱除率提高到81.25%;同时,MEA可以在短时间内高效吸收体系内的SO₂,且几乎不受其他气体成分的影响,SO₂脱除率保持在95%左右。     

煤化工烟道气毒性成分对Chlorella pyrenoidosa生长和细胞成分的影响

探究煤化工烟道气中毒性成分对微藻的影响是利用微藻固定煤化工烟道气CO₂实现减排的关键。本文利用不同浓度的NaHS、Na₂SO₃和NH₃·H₂O培养Chlorella pyrenoidosa（C. pyrenoidosa）,以探究煤化工烟道气主要毒性成分H₂S、SO₂和NH₃气体水溶物的毒性。实验结果表明：NaHS、Na₂SO₃和NH₃·H₂O浓度分别低于1mmol/(L·d)、40mmol/(L·d)和7mmol/(L·d)时对C. pyrenoidosa生长无抑制作用,而且Na₂SO₃[＜40mmol/(L·d)]会显著促进 C. pyrenoidosa的生长;NaHS 添加4mmol/(L·d)时会在生长初期抑制C. pyrenoidosa的生长,NH₃·H₂O添加35mmol/(L·d)则会直接造成藻细胞的破碎死亡。与对照组相比,NaHS和Na₂SO₃浓度分别低于1mmol/(L·d)、10mmol/(L·d)时对C. pyrenoidosa的细胞成分无影响;NaHS添加4mmol/(L·d)使藻蛋白含量提高7.13%;Na₂SO₃添加40mmol/(L·d)使藻蛋白降低13.45%,总糖含量提高42.90%;NH₃·H₂O的添加会使藻蛋白含量降低,总糖含量提高。微藻生物质整体蛋白质含量较高,可作为蛋白饲料来源。研究结果表明,C. pyrenoidosa对煤化工烟道气中的主要毒性气体有较好的耐受性,利用煤化工烟道气培养微藻具有可行性。     

Microbial reduction of sulfur dioxide and nitric oxide

Two process concepts have been developed for a microbial contribution to the problem of flue gas desulfurization and NO_x removal. We have demonstrated that the sulfate-reducing bacterium Desulfovibrio desulfuricans can be grown in a mixed culture with fermentative heterotrophs in a medium in which glucose served as the only carbon source. Beneficial cross-feeding resulted in vigorous growth of D. desulfuricans, which used SO₂(g) as a terminal electron acceptor, with complete reduction of SO₂ to H₂S in 1–2 s of contact time. We have proposed that the concentrated SO₂ stream, obtained from regeneration of the sorbent in regenerable processes for flue gas desulfurization, could be split with two-thirds of the SO₂ reduced to H₂S by contact with a culture of sulfate-reducing bacteria. The resulting H₂S could then be combined with the remaining SO₂ and used as feed to a Claus reactor to produce elemental sulfur. However, the use of glucose as an electron donor in microbial SO₂ reducing cultures would be prohibitively expensive. Therefore, if microbial reduction of SO₂ is to be economically viable, less expensive electron donors must be found. Consequently, we have evaluated the use of municipal sewage sludge and elemental hydrogen as carbon and/or energy sources for SO₂ reducing cultures. Heat and alkali pretreated sewage sludge has been successfully used as a carbon and energy source to support SO₂ reduction in a continuous, anaerobic mixed culture containing D. desulfuricans. The culture operated for nine months with complete reduction of SO₂ and H₂S. Another sulfate-reducing bacterium, Desulfotomaculum orientis, has also been grown in batch cultures on a feed of SO₂, H₂ and CO₂. Complete reduction of SO₂ to H₂S was observed with gas-liquid contact times of 1–2 s. We have also demonstrated that the facultative anaerobe and chemoautotroph, Thiobacillus denitrificans, can be cultured anoxically in batch reactors using NO(g) as a terminal electron acceptor with reduction to elemental nitrogen. We have proposed that the concentrated stream of NO_x, as obtained from certain regenerable processes for flue gas desulfurization and NO_x removal, could be converted to elemental nitrogen for disposal by contact with a culture T. denitrificans. Two heterotrophic bacteria have also been identified which may be grown in batch cultures with succinate or heat and alkali pretreated sewage sludge as carbon and energy sources and NO as a terminal electron acceptor. These are Paracoccus denitrificans and Pseudomonas denitrificans.     

锆基双金属氧化物催化剂硫中毒的研究

在工业二氧化碳加氢制甲醇过程中,硫化氢气体的引入将对该过程中使用的催化剂活性及稳定性带来负面的影响。基于此,采用微反应合成法成功制备了InZrO_x和ZnZrO_x锆基催化剂,并研究了在二氧化碳加氢反应中,硫化氢气体对锆基催化剂的结构性质及其催化性能的影响规律。结果表明,在T=573 K、p=3.0 MPa和GHSV=18 000 mL/(g_cat·h)条件下,仅通入二氧化碳/氢气反应气时,InZrO_x和ZnZrO_x催化剂的二氧化碳转化率和甲醇选择性分别为7.2%、9.3%和93%、92%。在二氧化碳/氢气原料气中通入体积分数为5×10^-3硫化氢气体时,InZrO_x和ZnZrO_x催化剂的二氧化碳转化率和甲醇选择性都降为0,这主要是因为硫化氢气体占据了氧空位,导致锆基双金属氧化物催化剂硫中毒失活。当停止通硫化氢气体时,InZrO_x和ZnZrO_x催化剂的二氧化碳转化率和甲醇选择...