【作者】 刘晓；

【导师】 云志； 史美仁；

【作者基本信息】 南京工业大学 ， 化学工程， 2005， 博士

【摘要】 由于天然资源的限制,原油的硫含量和重金属含量有增加的趋势。与此同时,环境污染的加剧促使世界各国对所有的石油产品提出了越来越严格的硫含量的要求。这两方面的矛盾促使环境友好脱硫技术不断的发展。近年来,研究发现特定的SbSn金属间化合物由于其表面上的特殊微观结构及功能,可以在非常温和的常温常压条件下脱除油品中的硫和重金属,并且可以在一定的范围内调节石油的组成,SbSn金属间化合物的这种奇妙功能预示了一个新的研究方向。 本文对SbSn金属间化合物的制备及其优化进行了一些新的探索,并借助于X射线衍射(YLRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、差示扫描量热(DSC)、俄歇电子能谱(AES)等分析测试手段对所得材料进行了分析表征。以石油馏分中最难脱含硫化合物之一的噻吩为模型化合物,较详细的考察了这种功能材料的制备条件与脱硫性能的关系。主要内容如下: 首先,以纯Sb、Sn为原料采用熔炼法合成制备了SbSn金属间化合物。考查了原料配比和工艺条件等对产物合成及性能的影响。XRD结果表明,Sb/Sn原料质量比49:51,在高温下反应一段时间能够完全制备得到SbSn金属间化合物。XRD和TEM结果表明:快速冷却条件下制备的SbSn金属间化合物随温度升高平均晶粒度明显变小;与缓慢冷却相比,快速冷却制备的SbSn金属间化合物缺陷明显增多,具有脱硫性能的表面活性点也相应增多。缓慢冷却条件下,熔炼温度升高,可增大产物的结晶度和致密度。熔炼时间愈长,产物的结晶度和致密度也愈高,但时间的影响不如温度显著。AES结果说明,SbSn金属间化合物最外层主要由Sb组成。为了找到熔炼法制备SbSn金属间化合物的最佳条件,脱硫过程中采用正交实验和单因素实验相结合的方法,考察了原料配比、反应温度、反应时间、Sb粒径大小和冷却方式对材料脱硫性能的影响。结果表明适宜的制备工艺条件为:Sb/Sn原料质量比49:51、反应温度950℃、反应时间60min、Sb粒径200目和快速冷却。单程脱硫的合适条件为:剂油比=0.6、脱硫时间30h和油包水型乳状液。在该脱硫条件下,SbSn金属间化合物对于模拟油品单程脱硫率为15%,对于汽油为11.8%。实验同时还考察了杂质原子的加入对材料脱硫性能的影响。实验表明,经Zn掺杂改性的金属间化合物脱硫性能有了明显的提高,最佳掺杂量为2%。经Zn掺杂改性后,单程脱硫率由15%提高到18.6%。Zn的掺杂可以有效地提高更多还原

【Abstract】 The quality of crude oil becomes poor with each passing day, the content of sulfur and heavy metal being increased. Meanwhile, aggravation of the environmental pollution impels all the countries in the world to put forward stricter and stricter criterion of sulfur content for all oil products. The conflicts of the two aspects promote the development of environmentally friendly technology. In recent years, it was reported that SbSn intermetallic compound could remove sulfur and heavy metal from oil and regulate the group composition of the petroleum to a certain extent under room temperature and ambient pressure because of its special surface micro-structure and function. The desulfurization and demetalization performance of the SbSn indicates a new research field.This study focused on the preparation and modification of SbSn intermetallic compound. The analysis and characterization of SbSn were carried out with the aid of modern analytical techniques, including XRD、 SEM、 TEM、 DSC and AES etc. The desulfurization performance of the functional material was researched in detail by using thiophene—one of the most difficult removal sulfur compound in petroleum cut fractoion as model compound in this dissertation. The following results have been obtained.Primarily, the SbSn was prepared by smelting with Sb、 Sn as raw materials. The effects of mass ratio and preparation conditions on the desulfurization performance of SbSn were investigated. The results of XRD showed that the SbSn could be prepared by smelting at high temperature for a period of time with raw material mass ratio of 49:51 (Sb:Sn). As indicated by XRD and TEM analysis, the average grain size of SbSn decreased with the temperature increased; the defects of SbSn intermetallic compound prepared by fast cooling were much more than that prepared by cooling slowly and the active spot on the surface of SbSn increased accordingly. Under cooling slowly condition, the crystallinity and density of SbSn would be improved with the increase of the reaction temperature; the longer the reaction time was, the better the crystallinity and density was, but the influence of reaction time was less than that of reaction temperature. The surface of SbSn intermetallic compound consisted of element Sb mainly by AES. Orthogonal experiments and mono-factorial analysis were used to find out the optimal preparationconditions of SbSn prepared by smelting. The influence of mass ratio, reaction temperature, reaction time, the particle size of Sb and cooling method on the desulfurization performance of SbSn were studied. The desulfurization experimental results showed that the preferable material preparation conditions were: m(Sb):m(Sn)=49:51, the reaction temperature 950 ℃, the reaction time 60min, the particle size of Sb less than 200 meshes and fast cooling. The optimum conditions for desulfurization were: the ratio of SbSn and oil was 0.6, desulfurization time was 30h and the w/o emulsion was used. Under single pass, the sulfur removal ratio for simulated oil was 15.0% and for gasoline was 11.8%. Adding a third metal element, especially, by an amount of Zn could enhance the desulfurization performance of SbSn obviously. The sulfur removal ratio for simulated oil was increased to 18.6% from 15% by mixing 2wt% of Zn in SbSn.Secondly, the possibility of preparation of SbSn intermetallic compound by mechanical alloying (MA) was investigated. The influence of the ball milling technology and the proportion of raw materials (Sb and Sn) on the MA was studied. The MA mechanism was discussed too. The results showed that, in a certain range of the raw material mass ratio (Sb:Sn), the SbSn intermetallic compound could be prepared by mechanical alloying. It does not accord with the phase diagram. The composition of the SbSn intermetallic prepared by MA could be far apart from its equilibrium value implied that the solid solubility could be greatly enhanced by the mechanical alloying. The results of characterization showed that both the grain size and the particle size of SbSn decreased with the milling time, the large lattice distortion occurred inside the grains and the fast diffusion increased due to the high density of lattice defects. The desulfurization experimental results showed that the optimum preparation conditions of mechanical alloying were: m(Sb):m(Sn)=49:51, bprs10:1 and rotation speed 270r/min.Thirdly, the annealing experiments of SbSn were carried out. The results of desulfurization experiments indicated that the desulfurization performance of SbSn treated by annealing at temperature from 60 ℃ to 120℃ decreased notably. The results of XRD showed that the average grain size of the SbSn increased with the annealing temperature. While the SbSn annealed at low temperature, the desulfurization performance of the SbSn decreased remarkably showed that the vacancy defect and"defect density" decreased.Finally, it is necessary to carry out regeneration for SbSn because it lost activity after single pass for desulfurization. Several cleaning methods for restoring its desulfurization activity were investigated. It was found that regeneration by methylbenzene washing was an appropriate method. The activity of the SbSn would be renewed to a certain extent by methylbenzene immerging. The circulation tests for desulfurization were also done. A total sulfur removal ratio of 32% for simulated oil was obtained after continuous treatments of the simulated oil three times with the fresh smelting SbSn (first treatment) and the used smelting SbSn immerged by methylbenzene (second and third treatment). Similarly, a total sulfur removal ratio of 23% was obtained by using the MA SbSn.更多还原