对苯二甲酸加氢精制钯/炭催化剂的制备

选取椰壳活性炭为载体制备钯／炭催化剂，考察了浸渍液pH值和还原温度对催化剂结构和活性的影响。用XRD对催化剂进行表征，用对苯二甲酸加氢精制体系进行活性评价。结果表明：催化剂的制备条件对载体炭孔结构影响不明显，金属钯较好的分散在载体炭上；最佳浸渍溶液pH值为1.5，还原温度为250℃。     

EDS表面分析研究Pd／C催化剂的失活原因

利用Ｘ射线能谱仪及原子吸收研究了对苯二甲酸加氢精制过程中失活的钯炭催化剂的失活原因,结果表明,原料中的含硫化合物,以二甲苯氧化工段的催化剂四溴乙铵,设备腐蚀和溶剂水中的离子均会沉积在钯炭催化剂的表面,引起催化剂加氢活性的下降,利用ＥＤＳ分析把炭催化剂及断面的元素沉积是分析催化剂失活原因的有效方法。     

从废钯－炭催化剂中回收氯化钯

从废钯－炭催化剂中回收氯化钯曹善文（济南化纤研究院，２５０１００）随着聚酯工业的飞速发展，用于粗对苯二甲酸（简称ＴＡ）加氢精制过程的钯－炭催化剂，使用量越来越大。就１９９３年国内情况看，年使用量已超过６７ｔ，预计到２０００年，年需要量将超过１３０ｔ。...     

精制对苯二甲酸用钯炭催化剂的工业试验

对比分析了对苯二甲酸加氢精制用钯炭催化剂的制备技术和工业试验情况。工业试验结果表明．大分子有机物吸附和覆盖了催化剂活性中心是催化剂暂时性失活的主要原因。经过碱洗,可以使催化剂再生,生产操作中控制浆料浓度／饱和溶解度小于90％、原料杂质以及反应压力,有利于提高催化剂使用寿命。     

对苯二甲酸加氢精制催化剂的研究进展

详述了对苯二甲酸加氢精制工艺用钯/活性炭(Pd/C)催化剂、非碳载体的Pd催化剂和多活性中心催化剂的研究进展;指出我国催化剂研究在抗磨损、抗硫性能、钯晶粒易长大等方面与国外的差距较大,今后应研发以二氧化钛、纳米碳等为新型载体制备的催化剂,进一步开发Pd/C催化剂以实现精对苯二甲酸工业化生产。     

对苯二甲酸精制钯炭催化剂内扩散及有效因子的研究

在高压间歇反应釜研究了对苯二甲酸中杂质对羧基苯甲醛（4-CBA）在不同粒径的钯炭催化剂上进行加氢反应的特性。结果表明,催化剂粒径对4-CBA的加氢反应影响较大,催化剂的粒径减小,有效因子增大,反应速率增大,反应为内扩散控制。在反应温度150 ℃和240 ℃条件下,测定了钯炭催化剂内扩散有效因子,估算4-CBA在钯炭催化剂内的有效扩散系数Deff和催化剂的曲折因子,并提出了钯炭催化剂开发的改进方向。     

对苯二甲酸精制钯炭催化剂载体活性炭的研究

分析了不同厂家生产的对苯二甲酸精制用钯炭催化剂载体活性炭的各种物性指标。实验结果表明,各种活性炭比表面相同时,其吸附量基本相近,但孔结构有较大差异,尤其是中孔孔容相差较大。中孔孔容增大,有利于钯炭催化剂分散度的提高和热稳定性增强.活性炭的表面基团对催化剂分散度也有影响,表面酸性基团含量增加,值化剂分散度提高.     

精制对苯二甲酸工艺的研究进展

介绍了精制对苯二甲酸工艺的现状,阐述了加氢精制法、DMT法、溶剂萃取、超临界精制工艺的技术特点。重点评述了加氢精制工艺在计算机控制、反应器改进、催化剂改性及国产催化剂CTP系列的应用进展。     

Pd/C催化剂研究进展

介绍了近年来对苯二甲酸加氢精制Pd/C催化剂的研究开发情况,包括催化剂性能及催化剂制备工艺。着重介绍了该催化剂性能改进、催化剂载体活性炭的预处理工艺以及浸渍溶液中添加辅助溶液的研究进展。     

对苯二甲酸加氢精制Pd/C催化剂的性能比较

对几种对苯二甲酸加氢精制Pd/C催化剂使用前后性能进行了比较。结果表明,NCTH-100催化剂与国外同类型催化剂性能相当,能够满足工业应用要求。     

重整催化剂的抗硫性能研究进展

基于固体氧化物燃料电池(SOFC)的烃类原位重整供氢技术是重要的分布式和小型化制氢方案。传统镍基重整催化剂在烃类重整过程中,原料中微量的硫化物即可使催化剂中毒失活,严重时还可能造成巨大的安全隐患。本文梳理总结了催化剂硫中毒的机理,简述了天然气、液化石油气、液态烃重整原料中硫化物的组成和含量,重点分析了已报道的用于重整反应的抗硫催化剂并总结了有效可行的催化剂抗硫方案,并从重整制氢催化剂的硫中毒机理指导高效抗硫催化剂的开发。最后,文章指出,重整催化综合性能的提升、重整原料的预处理和重整反应器设计等综合抗硫策略也是重要的研究方向。     

Progress in the sulfur resistance of reforming catalysts

Hydrocarbon in-situ reforming hydrogen supply technology based on solid oxide fuel cell (SOFC) is an important distributed and miniaturized hydrogen production solution. Traditional nickel-based reforming catalysts often face sulfur poisoning during the reaction with trace amount of sulfur in the feedstock. In some cases, the existing sulfur may even cause severe safety risks. In this paper, the mechanisms of sulfur poisoning are summarized; the compositions and contents of sulfur species in natural gas, liquefied petroleum gas and liquid hydrocarbon are briefly described; the reported sulfur resistant catalysts for different reforming reactions are reviewed, and the effective and feasible solutions for developing sulfur-tolerant catalysts are summarized. The mechanisms of sulfur poisoning could guide the design of sulfur-resistant reforming catalyst with high performance. Finally, the paper reveals that the improvement of catalytic overall performance, the pretreatment of reforming feedstock and the design of reforming reactor and other comprehensive anti-sulfur strategies are also important research directions.     

Iridium supported catalysts. variation of sulfur coverage with the nature of the carrier

The study concerns the adsorption of H₂S, at 543 K, on iridium supported catalysts, having a high dispersion of the metallic phase and presenting different resistance to sulfur poisoning. The results show that sulfur coverage of the catalysts decreases when increases the activity of the carrier. This decrease in sulfur adsorption seems another proof that small iridium particles supported on acidic carriers are electron deficient. Finally, it appears that, in a middle temperature range, thiotolerance is linked to sulfur coverage and not to the nature of the sulfur poisoning moities.     

助剂对PdO/Al2O3催化剂的抗硫中毒性能影响

浸渍法制备了不同助剂掺杂的PdO/Al<,2>O<,3>催化剂,以H<,2>S为硫源考察了催化剂的抗硫中毒性能以及催化剂对甲烷的催化燃烧性能,并用库仑滴定法测定了中毒及再生后催化剂表面的含硫量,以此分析催化剂中毒模式.结果表明,助剂MgO、ZnO<,2>、K<,2>O的添加均不同程度的提高了催化剂的抗硫中毒性能.再生后...     

固体氧化物燃料电池阳极的硫毒化与再生活化

固体氧化物燃料电池(SOFC)的阳极在使用含硫廉价燃料时极易发生硫中毒现象,导致电池性能迅速衰退。本综述在介绍SOFC电极反应机制的基础上,结合近些年的文献,对不同材料的阳极硫中毒现象进行了汇总,分析了阳极硫毒化和活化规律,深入探究了硫中毒物理与化学机制,总结了硫中毒阳极的再生及活化新方法,并分析了相关再生机制。     

Poisoning and Regeneration of an Ni/SiO2 Catalyst

The poisoning effect of thiophene during the hydrogenation of styrene on an Ni/SiO₂ catalyst, and the regenerating role of both pure hydrogen and 2-butyne in the presence of hydrogen on the poisoned catalyst, were studied. The treatments induced the elimination of sulfur and promoted an important recovery of the catalytic activity and selectivity. XPS analyses show that the sulfur species adsorbed during the catalyst poisoning is thiophene. Part of the sulfur remained irreversibly adsorbed after the regeneration treatments carried out at 473 K; a modification on the adsorbed sulfur electronic state was detected, which can be ascribed to thiophene hydrogenolysis induced by the regenerating temperature. © 1997 SCI.     

C207型联醇催化剂中毒原因探讨

通过对从工业合成塔内不同轴向位置取出使用后的C207型铜基甲醇催化剂的俄歇电子能谱, X-射线衍射和孔结构参数测定和研究, 表明铜基联醇催化剂可发生硫中毒、结焦和羰基铁中毒。发现催化剂中毒失活后孔结构参数和晶格结构发生较大变化。     

Poisoning of nickel-based catalysts in fat hydrogenation

The influence of various poisoning compounds on the hydrogenation of fat is reviewed. Sulfur-containing compounds, present in both vegetable and marine oils, create serious catalyst deactivation problems. In this paper, the poisoning efffect of sulfur and its role on the reactant adsorption in different hydrogenation reactions are discussed. Several factors affecting the sulfur resistance of the catalyst metal are summarized. Other inhibitors influencing the fat hydrogenation, such as phosphorus compounds, free fatty acids, sodium soaps, chlorophyll, halogen compounds and products of lipid oxidation, are also considered.     

The role of sulfur in commercial iron-based Fischer–Tropsch catalysis with focus on C2-product selectivity and yield

This paper presents some insight into the role of sulfur, a well-known Fischer–Tropsch (FT) catalyst poison, regarding the selectivity of ethylene:ethane and C₂-product yield in a commercial, Fe-based, high-temperature, 2-phase FT process.

It is well known that in these kind of processes, the level of sulfur allowed in the feed gas is normally very low (ppb range) and aggressively kept low due to the poisoning effects. The practice generally is to get sulfur levels down as close as possible to zero.

The poisoning effects are well studied in research work and significant information exists in that regard. It is, e.g. known that the poisoning action of sulfur would typically increase selectivity towards more hydrogenated ethane relative to ethylene (the more attractive product). At high enough levels it would kill catalyst activity completely.

This paper highlights the role of sulfur in a typical commercial operation. Data from a period of almost 2 years was used. It was found that under the prevailing actual commercial scale operating conditions, sulfur did not behave as a poison to the catalyst. However, its effect did not become completely negligible either. There were strong indications of sulfur promoting selectivity shifts towards more olefinic C₂-product. These results were also independently confirmed on a different set of data and a different kind of commercial reactor.     

Sulfur Adsorption and Poisoning of Metallic Catalysts

The catalytic activity of most transition metals is drastically reduced by the presence of hydrogen sulfide or other sulfur-containing compounds at extremely low concentration in the reagents. This poisoning effect is a major problem in many catalytic reactions, especially hydrogen reaction such as methanation of coal synthesis gas or reforming of naphthas. On the other hand, beneficial effects on the selectivity can be obtained by a partial and well-controlled poisoning of catalysts by sulfur. For example, an enhancement of the selectivity for heavier hydrocarbons in the CO + H₂ reaction has been reported [1-3]. Increases of the selectivity for partial hydrogenation of diolefins to the corresponding monoolefins were also observed [4, 5]. In the catalytic reforming of naphthas, partial poisoning by sulfur minimizes excessive hydrocracking.