三聚氰胺法制备BN吸附材料在燃油脱硫中的应用

发布时间：2018-04-08 11:44

  本文选题：氮化硼　切入点：三聚氰胺　出处：《江苏大学》2017年硕士论文

【摘要】：燃油中的含硫化合物经燃烧后产生的SOx,NOx等有毒有害气体对空气、水等人类生存环境造成了严重的威胁。抑制或者减少硫的排放量成为当前的一个热点话题。工业上传统的加氢脱硫(HDS)技术虽然能够将燃油中的硫醚、硫醇、噻吩化合物轻易地除去,然而对于像含有大量二苯并噻吩(DBT)及其衍生物的柴油,运用HDS技术需要更高的温度和压力,消耗更多的氢气,同时在如此苛刻的条件下,油品的损失也会增加,这大大提高了生产成本。与HDS技术相比,吸附脱硫(ADS)技术具有耗能低、操作条件温和等优点而被认为是极具应用前景的技术之一。本论文设计合成了一系列氰胺化合物衍生的氮化硼(BN)吸附剂并用于燃油吸附脱硫研究。在该工作中,以三聚氰胺(C3H6N6)、二聚氰胺(C2H4N4)、单氰胺(CH2N2)为氮源用于改变BN的纳米结构。其中,以C3H6N6为氮源合成得到的BN是一种多孔纳米片堆集而成的类棒状结构,且具有很高的吸附脱硫性能。这种结构的BN能够暴露更多的边缘且在其表面形成孔结构,从而有大量的低配位原子存在,提供更多的吸附位点,大大提升了BN的吸附性能。该吸附剂对硫含量为500 ppm的模拟油的吸附容量达到了40.2 mgS·g-1 adsorbent。此外,对极难脱除的4,6-DMDBT,该吸附剂依然展现了极佳的吸附性能。鉴于前面的工作基础,通过引入电负性更高的杂原子可以提升B原子的正电性,从而增强BN与硫化物之间的相互作用。为了进一步提高BN的吸附性能,以硼酸和三聚氰胺为原料、P123为模板剂,成功合成了一种氧原子掺杂的介孔BN纳米线。通过多种表征手段研究了合成的BN的结构、形貌、表面性质以及电子结构。所得的介孔BN纳米线首次被用于燃油吸附脱硫考察,对模拟油中DBT具有极佳的吸附性能,根据Langmuir吸附曲线拟合得到理论最大吸附容量为65.4 mgS·g-1 adsorbent。与商品级BN和类石墨烯BN相比,其吸附性能大幅度提升,这主要是由于氧原子的引入增强了吸附剂与硫化物之间的相互作用。此外,介孔BN纳米线具有很好的稳定性,而且对4,6-DMDBT的吸附容量达到了33.2 mgS·g-1 adsorbent。尽管掺杂氧原子能够增强BN与硫化物之间的相互作用,但是氧原子掺杂的BN吸附剂的吸附性能并不能满足当前的国Ⅴ标准需求。因此,针对目前燃油的国Ⅴ标准,本工作进一步通过模板法在较低温度下合成了一系列的BN吸附剂。旨在通过调节模板剂的种类、用量、合成温度,优化BN的吸附脱硫性能。经过优化之后的活性BN-P123吸附剂具有较大的比表面积,其比表面积达到了1185m2·g-1,对初始硫含量为500 ppm的模拟油中DBT的吸附容量达到了45.7 mgS·g-1adsorbent。此外,合成得到的活性BN-P123吸附剂能够实现燃油的深度脱硫,达到目前所需要的燃油标准(10 ppm)。该活性BN-P123吸附剂具有无毒、无金属、高吸附脱硫性能,有望在工业上得到应用。
[Abstract]:So _ xN _ x and other toxic and harmful gases produced by burning sulfur compounds in fuel oil pose a serious threat to the living environment of human beings such as air, water and so on.Restraining or reducing sulfur emissions has become a hot topic.Although the traditional industrial hydrodesulfurization (HDS) technology can easily remove thioether, mercaptan and thiophene compounds from fuel oil, however, for diesel oil such as diesel containing a large amount of dibenzothiophene (DBT) and its derivatives,Using HDS technology requires higher temperature and pressure to consume more hydrogen. At the same time, the loss of oil will increase under such harsh conditions, which greatly increases the production cost.Compared with HDS technology, adsorption desulfurization (HDS) technology has the advantages of low energy consumption and mild operating conditions, so it is considered to be one of the most promising technologies.A series of boron nitride (BN) adsorbents derived from cyanamide compounds were designed and synthesized in this paper.In this work, melamine C _ 3H _ 6N _ 6C _ 3H _ 6N _ 6, C _ 2H _ 4N _ 4N _ 4 and Ch _ 2N _ 2) were used as nitrogen sources to change the nanostructure of BN.The BN synthesized with C3H6N6 as nitrogen source is a kind of rod-like structure stacked by porous nanochips and has high adsorption and desulfurization performance.The BN with this structure can expose more edges and form pore structures on its surface, thus there are a large number of low coordination atoms, providing more adsorption sites, which greatly improves the adsorption performance of BN.The adsorption capacity of the adsorbent for the simulated oil with sulfur content of 500 ppm was 40.2 mgS g ~ (-1) adsorbent.In addition, the adsorbent showed excellent adsorption properties for 4H 6 DMDBT, which is very difficult to be removed.In view of the previous work, the interaction between BN and sulfides can be enhanced by introducing higher electronegativity heteroatoms to enhance the positive charge of B atoms.In order to further improve the adsorption properties of BN, a mesoporous BN nanowire doped with oxygen atom was successfully synthesized with boric acid and melamine as template.The structure, morphology, surface properties and electronic structure of the synthesized BN were studied by various characterization methods.The mesoporous BN nanowires have been used for the first time to investigate the desulfurization of fuel oil. The mesoporous BN nanowires have excellent adsorption performance for DBT in simulated oil. The theoretical maximum adsorption capacity is 65.4 mgS g-1 adsorbent. according to Langmuir adsorption curve fitting.Compared with commodity grade BN and graphene like BN, the adsorption properties of the adsorbents were greatly improved, which was mainly due to the introduction of oxygen atoms to enhance the interaction between adsorbents and sulfides.In addition, the mesoporous BN nanowires have good stability, and the adsorption capacity of 4-DMDBT reaches 33.2 mgS g-1 adsorbent.Although doping oxygen atoms can enhance the interaction between BN and sulfides, the adsorption properties of oxygen atom doped BN adsorbents can not meet the needs of current state 鈪，

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