【作者】 赵丽霞；

【导师】 李钢；

【作者基本信息】 大连理工大学 ， 工业催化， 2007， 硕士

【摘要】 世界各国为加强对环境污染的控制，不断提出更加严格的液体燃料含硫标准。面对不断降低的硫含量，传统加氢工艺受到挑战。目前，氧化脱硫法由于其反应条件温和、设备简单、脱硫效果好，成为研究的热点。本文以钛硅分子筛为催化剂，双氧水为氧化剂，对同时含有噻吩、苯并噻吩、二苯并噻吩和4，6-二甲基二苯并噻吩多种硫化物的模拟燃料进行了氧化脱硫研究。考察了反应温度、催化剂孔径及种类对脱硫结果的影响。研究得出如下结论：提高反应温度可明显提高硫化物的脱除率，并且可以缩短反应达到平衡的时间；采用较大孔径的Ti-HMS分子筛做催化剂可以提高大分子硫化物4，6-二甲基二苯并噻吩的氧化脱除率；对于含大分子硫化物较多的模拟燃料，单独采用中孔分子筛Ti-HMS做催化剂即可达到较好的脱硫效果；对于含小分子硫化物较多的模拟燃料，以Ti-HMS与微孔分子筛TS-1的混合物或中微孔复合分子筛Ti-WMS做催化剂脱硫效果更好。另外，本文采用有机碱四丙基氢氧化铵（TPAOH）对微米TS-1进行碱改性，以改性后的TS-1为催化剂，H₂O₂为氧化剂，对含有2-甲基噻吩的正辛烷模拟燃料进行氧化脱硫研究。采用XRD、UV-Vis、TEM、N₂物理吸附等手段对改性前后的样品进行表征。考察了TPAOH浓度、改性温度以及改性时间对微米TS-1氧化脱除2-甲基噻吩性能的影响。结果表明，与未改性的样品相比，改性后的TS-1骨架结构未发生明显变化，骨架钛和非骨架钛含量略有降低，并且生成一些尺寸约为1.4nm和40-60nm的孔，比表面积和孔容增加。TPAOH改性后TS-1对2-甲基噻吩的脱除率由改性前的70.5％提高到93.9％。最佳改性条件为：TPAOH的浓度0.4mol／l，改性温度413K，改性时间24h。更多还原

【Abstract】 Facing the increasing seriously environmental problems, the world has seen a more andmore stringent level for sulfur content in liquid fuels proposed in many countries. Thetraditional hydrodesulphurization process （HDS） becomes economically insufficient with thedecreasing sulfur in fuels. Currently, oxidative desulphurization （ODS） become the hotspotwhich is investigated extensively for its mild reaction condition, simple equipment, andhighly efficiency.In this paper, titanium containing molecular sieves and H₂O₂ were used as the catalystsand the oxidant, respectively, for the oxidative desulphurization of model fuel withmulti-types sulfur compounds including thiophene （Th）, benzothiophene （BT）,dibenzothiophene （DBT） and 4, 6-dimethyldibenzothiophene（4, 6-DMDBT）. The effect of thereaction temperature and the pore size and kinds of the catalysts on oxidative desulphurizationwas investigated. It has been shown that with the increase of the reaction temperature, theremoval rates of sulfur compounds have been improved. In addition, the reaction speed evenfast and reached the balance in a short time under higher temperature. The removal efficiencyof 4, 6-DMDBT was enhanced when the Ti-HMS with larger pore size was used as catalyst.Ti-HMS exhibited high activity in the oxidative desulphurization of model fuel, in which thelarge molecular sulfur compounds are in the majority. However, the meso-microporouscomposite Ti-WMS and mixture of Ti-HMS and TS-1 were preferable for oxidativedesulphurization of the model fuel containing more small molecular sulfides.The micron-scale TS-1 was modified by tetrapropylammonium hydroxide （TPAOH）.The modified TS-1 was used as the catalyst in oxidative desulphurization of2-methylthiophene from model fuel and exhibited high activity. The samples before and aftermodification were characterized by XRD, UV-Vis, N₂ physical adsorption/desorption andTEM techniques. The modification conditions were investigated, including the concentrationof TPAOH, the modification temperature and the modification time. It has been shown thatthe modified sample possessed the typical MFI structure. After modification, the content offramework titanium as well as the extra-framework titanium in TS-1 decreased. However, themodified sample has larger surface area and pore volume than the original sample. In addition,some larger pores of about 1.4 nm and 40-60 nm have been found in the modified TS-1sample, which may be responsible for the improvement of catalytic behavior of TS-1. The modified sample exhibits excellent activity in oxidative removal of 2-Methylthiophene, withthe removal rate of 93.9％, much higher than that of original sample （70.5％）. The optimalmodification conditions are as follows: the concentration of TPAOH is 0.4mol/l; thetemperature is 413K; the time is 24 h.更多还原