【作者】 刘日嘉；

【导师】 王睿；

【作者基本信息】 山东大学 ， 环境工程， 2014， 博士

【摘要】 燃料油中的含硫化合物燃烧后产生的SOx,其中最主要的是SO2。S02是大气环境的主要污染源,是形成酸雨的直接原因。酸雨会造成树木死亡、粮食减产、水质酸化、建筑物腐蚀,进而使生态环境恶化。而且,燃油中的含硫化合物燃烧后的生成物会使汽车尾气转化器中的催化剂中毒,进而影响了催化转化器性能的发挥,导致汽车尾气中三种主要有害物质HC、CO、NOx的排放量增加。鉴于燃油中含硫化合物燃烧所产生的危害,世界各国对燃油中硫含量的标准越加苛刻。因此,生产低硫“清洁燃料”已成为必然趋势。在燃油硫化物去除的众多方法中,氧化脱硫(oxidative desulfurization,ODS)以反应条件温和(常温、常压)、无需氢源、工艺流程简单、脱硫率高、设备投资少、运行费用低、不产生二次污染等优点而成为燃油脱硫的研究热点之一。杂多化合物(HPCs)以其独特的晶格结构及催化性能而被广泛应用于氧化脱硫领域。本文通过多种途径,制备出具有深度脱硫催化活性的高效可回收杂多化合物复合型催化剂,综合运用FT-IR、XRD、ICP-OES、 TEM、VSM、TGA-DSC、元素分析等检测手段对制备的催化剂进行分析表征,同时对各催化剂脱硫性能作出系统评价。研究主要内容分为以下六个方面：一、以六种金属盐和磷钨酸为原料制备了Keggin结构杂多酸盐Mx/nH0.6PW(Zr0.6H0.6PW、Al0.8H0.6PW、Zn1.2H0.6PW、 Feo.g H0.6PW、Ti0.6H0.6PW和Sno.6Ho.6PW)和Alx/3H3-xPW (AIPW、Al0.8H0.6PW、Al0.5H1.5PW、Alo.3H2.1PW和Al0.1H2.7PW)催化剂,并对催化剂进行了FT-IR、XRD和DSC/TGA表征。催化剂活性筛选结果表明：所制备的催化剂均具有极佳的催化氧化脱硫性能,各催化剂对模拟油品中二苯并噻吩(DBT)的催化活性大小顺序如下,不同金属原子取代的杂多酸盐催化活性大小顺序为：Al0.8H0.6PW> Ti0.6H0.6PW>Zr0.6H0.6PW> Sn0.6H0.6PW> Fe0.8H0.6PW>Zn1.2h0.6PW。不同铝原子和氢原子配比的杂多酸盐催化活性大小顺序为：Al0.5H1.5PW> Al0.8H0.6PW> Al0.3H2.1PW> AIPW> Al0.1H2.7PW。其中,Al0.5H1.5PW的催化活性要高于磷钨酸(HPW),确定Al0.5H1.5PW为最佳催化剂。并研究了以Al0.5H1.5PW为催化剂,过氧化氢为氧化剂,乙腈为萃取剂的燃油催化氧化萃取深度脱硫技术。实验考察了催化剂用量、氧硫比、催化剂与氧化剂预接触时间、反应温度和初始硫含量对脱硫效果的影响。实验结果表明,在催化剂用量为模拟油品质量的0.25%,O/S为10,催化剂与过氧化氢预接触8min,反应温度60℃,初始硫含量为500ppmw的条件下,反应到180min时,已几乎检测不到含硫化合物的存在。此外,催化剂用于真实汽、柴油的催化氧化脱硫实验也得到了很好的脱硫效果,稳定汽油脱硫完成后再进行3次连续萃取,硫含量从350ppmw降至11.2ppmw,脱硫率达96.8%。催化柴油脱硫完成后再进行3次连续萃取,硫含量从350ppmw降至8.9ppmw,脱硫率达97.5%。且催化剂重复使用5次后,脱硫效率未见明显降低。二、通过置换反应,将适宜的有机阳离子与杂多阴离子组装成新的具有特殊性能的有机-无机杂化型催化剂。本文合成了三种有机-无机杂化型催化剂,分别为：[π-C5H5NC16H33]3[PO4(WO3)4]、[π-C5H5NC16H33]3[PO4(WO3)4]和[π-C5H5NC16H33]3[PO4(WO3)4],经FT-IR分析以上三种有机-无机杂化型催化剂均具有Keggin特征结构。考察了这三种有机-无机杂化型催化剂在氧化脱硫体系中的催化性能。结果表明,这三种有机-无机杂化型催化剂脱硫活性顺序为：[π-C5H5NC16H33]3[PO4(WO3)4]>[π-C5H5NC16H33]3[PO4(WO3)4]>[π-C5H5NC16H33]3[PO4(WO3)4]。以[π-C5H5NC16H33]3[PO4(WO3)4]为最佳催化剂,过氧化氢为氧化剂,乙腈为萃取剂的燃油催化氧化萃取深度脱硫研究。实验考察了催化剂用量、氧硫比、催化剂与氧化剂预接触时间、反应温度和初始硫含量对脱硫效果的影响。结果表明,在最佳实验条件下,即催化剂用量为占模拟油品质量的0.25%、O/S为10、温度50℃、催化剂与氧化剂分别加入反应体系中,即反应时先将催化剂加入反应体系,然后迅速加入一定量的过氧化氢进行脱硫反应。实验结果显示,噻吩类含硫化合物被氧化难易顺序为：DBT>4,6-DMDBT> BT>TH。证明了氧化脱硫反应中,噻吩类硫化物氧化活性难易程度,不但受其本身硫原子电子云密度影响,还受到硫原子周围的空间位阻效应影响。在最佳实验条件下,反应至180min,催化剂对初始硫含量500ppmw的模拟油品中硫化物催化脱除效率可达99.9%。催化剂经三次再生,循环利用,对DBT的脱除率仍可维持在99.2%左右,具有良好的可再生性。此外,将催化剂用于稳定汽油、催化柴油的脱硫实验。在脱硫完成、萃取后,均可将初始硫含量为350ppmw的真实燃油硫含量降至15ppmw以下,满足美国环保局(EPA)的低硫燃油标准。三、通过离子交换法,将杂多化合物的阴离子固定在不同种类的离子交换树脂上,制备出以离子交换树脂为基体的杂多化合物复合型催化剂,分别为：HPW/D296、HPW/D201、HPW/D081、HPW/DOO1-CC和HPW/201×7,研究了上述催化剂对模拟油品中DBT的脱除性能。结果表明,催化脱硫活性顺序为：HPW/D296> HPW/D201> HPW/201×7> HPW/D081> HPW/D001-CC。以HPW/D296为最佳催化剂,过氧化氢为氧化剂,乙腈为萃取剂的燃油催化氧化萃取深度脱硫技术。实验考察了催化剂用量、氧硫比、催化剂与氧化剂预接触时间、反应温度和初始硫含量对脱硫效果的影响。在最佳实验条件：催化剂用量为占真实燃油质量的2.70%、O/S为28、温度60℃和催化剂与氧化剂预接触时间为8min,反应至180min,催化剂对初始硫含量为500ppmw的模拟油品中DBT的脱除效率为93.5%,且催化剂具有较好的再生催化效果。在最佳实验条件下,考察了催化剂对四种真实燃油的脱硫效果。结果显示催化剂对真实燃油的催化脱硫率顺序为：稳定汽油>催化柴油>-10号柴油>直馏柴油。随后,又对稳定汽油和催化柴油脱硫前后的质量(酸度、密度、水溶性酸碱、铜片腐蚀、机械杂质、辛烷值或十六烷值)及收率进行探讨,发现精制后的稳定汽油的辛烷值和柴油的十六烷值都有小幅提高,从而使燃油的安定性增强。催化剂对稳定汽油的脱硫率为85.1%,收率为96.5%；催化柴油的脱硫率为84%,收率为98.0%。四、制备并通过FT-IR、XRD、VSM、TEM和元素分析表征了可磁分离杂多化合物复合型纳米催化剂HPW/Fe3O4-SiO2,并将其用于燃油深度脱硫研究。结果表明,所制备的催化剂具有典型的“枣-核”型核壳结构,催化剂粒径在300nm左右。在最佳实验条件下：催化剂用量为占模拟油品质量的4.0%、O/S为20、催化剂与氧化剂预接触时间为8min和温度70℃下,催化剂对初始硫含量为500ppmw模拟油品中DBT的催化脱除效率为99.4%。此外,催化剂用于真实汽、柴油的催化氧化脱硫实验也得到了很好的脱硫效果,稳定汽油脱硫完成后再进行3次连续萃取,硫含量从350ppmw降至12.8ppmw,脱硫率达96.3%。催化柴油脱硫完成后再进行3次连续萃取,硫含量从350ppmw降至10.2ppmw,脱硫率达97.1%。催化剂在强磁场的吸引下,可从反应体系中迅速分离,且具有极好的再生催化性能。五、采用分散聚合法制得中空SiO2微粒,并将其氨基化后负载磷钨酸(HPW),最终制得氨基化中空Si02磷钨酸复合型催化剂NH4PW-SiO2,并对催化剂进行了N2吸脱附、FTIR、XRD、SEM和ICP-OES表征。研究了以NH4PW-SiO2为催化剂,过氧化氢为氧化剂,乙腈为萃取剂的燃油催化氧化萃取深度脱硫技术。实验考察了催化剂用量、氧硫比、催化剂与氧化剂预接触时间、反应温度和初始硫含量对脱硫效果的影响。实验结果表明,在催化剂用量为模拟油品质量的1.0%,O/S为15,催化剂与过氧化氢预接触4min,反应温度60℃,模拟油品初始硫含量为500ppmw的条件下,反应到180min时硫含量降至3.0ppmw,脱硫率达99.4%。催化氧化萃取时的脱硫率比单纯萃取时的脱硫率高45.1%,催化脱硫效果十分显著。此外,催化剂用于真实汽、柴油的催化氧化脱硫实验也得到了很好的脱硫效果,且催化剂重复使用5次后,脱硫效率未见明显降低。六、研究了典型噻吩类有机硫化物单组分模拟体系的催化氧化反应动力学,发现各有机硫化物的表观反应级数均为一级,且表观活化能顺序符合：DBT>4,6-DMDBT> BT> TH。并通过FT-IR动态监测过氧基团-0-0-的伸缩振动峰变化,探讨了催化氧化脱硫机理。结果表明,Keggin结构杂多酸(盐)催化剂或固载型Keggin结构杂多化合物复合型催化剂首先被H2O2氧化为强氧化性的过氧阴离子{PO4[WO(μ-O2)(O2)]4}3-,再通过过氧阴离子的强氧化性,将具有富电子的硫化物氧化成砜,通过萃取剂乙腈萃取脱除。更多还原

【Abstract】 Sulfur-containing compounds in transportation fuels are the most notorious and undesirable contaminants because they are converted to toxic sulfur oxides (SOX), and SO2is the foremost sulfur oxides through combustion that result in air pollution and acid rain, poison the oxidation catalysts in the emission control system and sulfur compounds in the fuel combustion causes the car exhaust catalyst poisoning reformer, resulting in three major automobile exhaust of harmful nitric oxide (NOx), hydrocarbons and carbon monoxide. Thus, ultra-deep desulfurization from transportation fuels has become an increasingly important subject worldwide, due to urgently environmental problems and increasingly stringent regulations. Oxidative desulfurization (ODS) is considered to be one of the most promising desulfurization methods for its mild reaction condition, high efficiency, simple technology, low cost, low carbon and environment-friendly. Heteropoly compounds have the advantage of unique lattice structure and high catalysis properties. Heteropoly compounds is widely used in the field of oxidative desulfurization. In this thesis, several efficiency of catalytic activity recyclable heteropoly compound catalyst have been made. The prepared catalyst was characterized by FTIR, XRD, ICP-OES, TEM, VSM, DSC/TGA and elemental analysis. And we studied the catalysis of these catalysts in the ODS process. The content of this thesis contains the following five parts.I) Keggin-type polyoxometalate catalyst Mx/nHo.6PW(Zr0.6H0.6PW, Al0.8H0.6PW, Zn1.2H0.6PW, Fe0.8H0.6PW, Ti0.6H0.6PW and Sn0.6H0.6PW) and Alx/3H3-xPW (A1PW, Al0.8H0.6PW, Al0.5H1.5PW, Al0.3H2.1PW and Al0.1H2.7PW) was prepared by6metal salts and phosphotungstate. The prepared catalyst was characterized by FTIR, XRD and DSC/TGA. Catalytic activity screening was carried out on the catalyst, it was determined that the synthesized catalysts with different metal atoms substituted showed excellent desulfurization ability in the following order:Al0.8Ho.6PW> Ti0.6H0.6PW> Zr0.6H0.6PW> Sn0.6Ho.6PW> Fe0.8H0.6PW> Zn1.2H0.6PW, and with different proportions of Al atoms and H atoms showed excellent desulfurization ability in the following order:Al0.5H1.5PW> Al0.8H0.6PW> Alo.3H2.1PW> AlPW> Al0.1H2.7PW, it was determined that the best cata was Al0.5H1.5PW. The method of catalytic extraction fuel ultra-deep desulfurization was proposed using hydrogen peroxide as oxidant and MeCN as extractants. The effects of catalyst dosage, O/S molar ratio, pre-immersion time of the catalyst in H2O2solution, reaction temperature and initial sulfur content. Under the favourable operating conditions were recommended as follows:mass ratio of catalyst dosage and simulated diesel of0.25%, O/S molar ratio of10, pre-immersion time of the catalyst in H2O2solution being8min and temperature of60℃, the sulfur content of simulated diesel was nearly0ppmw at180min. In addition, Alo.5H1.5PW showed excellent desulfurization efficiency for gasoline and diesel. As stable gasoline, the catalytic-oxidation-extraction sulfur content can be reduced from350ppmw to11.2ppmw and desulfurization ratio reached to96.8%after3times MeCN extractant. As catalytic diesel, the catalytic-oxidation-extraction sulfur content can be reduced from350ppmw to8.9ppmw and desulfurization ratio reached to97.5%after3times MeCN extractant. And the catalyst recovered demonstrated almost the same activity the fresh after5cycles.Ⅱ) In this paper, a suitable organic cations assembled into new heteropoly anion having special performance0organic-inorganic heteropolyacids catalyst by displacement reaction. In this paper, organic-inorganic heteropolyacids were prepared, including [π-C5H5NC16H33]3[PO4(WO3)4],[π-C5H5NC16H33]3[PO4(WO3)4] and [π-C5H5NC16H33]3[PO4(WO3)4]. All the organic-inorganic heteropolyacids catalyst has Keggin-type structure by FT-IR analysis. Catalytic activity screening was carried out on the catalyst, it was determined that the synthesized catalysts showed excellent desulfurization ability in the following order:[π-C5H5NC16H33]3[PO4(WO3)4]>[π-C5H5NC16H33]3[SiO4(WO3)4]>[π-C5H5NC16H33]3[PO4(WO3)4]. It was determined that the best cata was [7π-C5H5NC16H33]3[PO4(WO3)4]. The method of catalytic extraction fuel ultra-deep desulfurization was proposed using hydrogen peroxide as oxidant and MeCN as extractants. The effects of catalyst dosage, O/S molar ratio, pre-immersion time of the catalyst in H2O2solution, reaction temperature and initial sulfur content. Under the favourable operating conditions were recommended as follows:mass ratio of catalyst dosage and simulated diesel of0.25%, O/S molar ratio of10, pre-immersion time of the catalyst in H2O2solution being0min and temperature of50℃, the sulfer content of simulated diesel can be reduced from500ppmw to0.5ppmw, with a desulfurization efficiency of99.9%at180min. It also shows that the oxidation reactivity of different sulfur compounds was in the order of DBT>4.6-DMDBT> BT> TH. The result shows the electron density of sulfur compounds on the sulfur atoms and the space steric hindrance were two important factors in the ODS. Moreover,[π-C5H5NC16H33]3[PO4(WO3)4] for real gasoline and diesel catalytic oxidative desulfurization obtained with good effect meet the EPA low-sulfur fuel standards. And the catalyst recovered demonstrated almost the same activity the fresh after3cycles.Ⅲ) To prepare ion exchange resin composite with heteropoly compounds catalyst several types of ion exchange resin has been used, including HPW/D296, HPW/D201, HPW/D081, HPW/D001-CC and HPW/201×7. Catalytic activity screening was carried out on the catalyst, it was determined that the synthesized catalysts showed excellent desulfurization ability in the following order:HPW/D296> HPW/D201> HPW/201×7> HPW/D081> HPW/D001-CC. It was determined that the best cata was HPW/D296. The method of catalytic extraction fuel ultra-deep desulfurization was proposed using hydrogen peroxide as oxidant and MeCN as extractants. The effects of catalyst dosage, O/S molar ratio, pre-immersion time of the catalyst in H2O2solution, reaction temperature and initial sulfur content. Under the favourable operating conditions were recommended as follows:mass ratio of catalyst dosage and simulated diesel of2.70%, O/S molar ratio of28, pre-immersion time of the catalyst in H2O2solution being8min and temperature of60℃, the sulfer content of simulated diesel can be reduced from500ppmw to32.5ppmw, with a desulfurization efficiency of93.5%at180min. And the catalyst recovered demonstrated almost the same activity the fresh after3cycles. Under the favourable operating conditions, it was determined that the synthesized catalysts showed excellent desulfurization ability for real fuel oil in the following order:stable gasoline> catalytic diesel>-10#diesel>straight-run diesel. Subsequently, the stable gasoline and catalytic diesel (acidity, density, water soluble acids and alkalis, corrosiveness to copper, mechanical admixtures, octane number and cetane number) after desulfurization, and the yield were discussed, refined found stable after octane number of gasoline and diesel fuel cetane number has slightly improved, thereby enhancing the stability of the fuel. The stable gasoline desulfurization efficiency85.1%and the recovery rate96.5%. The catalytic diesel desulfurization efficiency84.0%and the recovery rate98.0%.IV) The Keggin-type magnetic isolated heteropoly compound composite nanocatalyst (HPW/Fe3O4-SiO2) was synthesized and characterized by FT-IR, XRD, VSM, TEM and elemental analysis. The results show that the catalyst prepared with typical "pit" type core-shell structure, the catalyst particle size of about300nm. Under the favourable operating conditions were recommended as follows:mass ratio of catalyst dosage and simulated diesel of4.0%, O/S molar ratio of20, pre-immersion time of the catalyst in H2O2solution being8min and temperature of70℃, the sulfer content of simulated diesel can be reduced from500ppmw to3.0ppmw, with a desulfurization efficiency of99.4%at180min. In addition, HPW/FesO4-SiO2showed excellent desulfurization efficiency for gasoline and diesel. As stable gasoline, the catalytic-oxidation-extraction sulfur content can be reduced from350ppmw to12.8ppmw and desulfurization ratio reached to96.3%after3times MeCN extractant. As catalytic diesel, the catalytic-oxidation-extraction sulfur content can be reduced from350ppmw to10.2ppmw and desulfurization ratio reached to97.1%after3times MeCN extractant. And the catalyst recovered easily by strong magnetic field, and demonstrated almost the same activity the fresh after3cycles.V) Hollow silica were prepared by dispersion aggragation before uploading HPW. The prepared catalyst was characterized by N2adsorption/desorption FTIR, XRD and SEM The method of catalytic extraction fuel ultra-deep desulfurization was developed using hydrogen peroxide as oxidant and MeCN as extractants. The effects of catalyst dosage, O/S molar ratio, pre-immersion time of the catalyst in H2O2solution, reaction temperature and initial sulfur content were investigated. Under the favourable operating conditions recommended as follows:mass ratio of catalyst dosage and simulated diesel of1.0%, O/S molar ratio of15, pre-immersion time of the catalyst in H2O2solution being4min and temperature of60℃, the sulfur content of simulated diesel can be reduced from500ppmw to3.0ppmw, with a desulfurization efficiency of99.4%at180min. The overal desulfurization efficiency reaches99.3%, higher than that by mere extraction by45.1%, efficiency significantly. Moreover, NH4PW-SiO2for real gasoline and diesel catalytic oxidative desulfurization was obtained with good effect and the catalyst recovered demonstrates almost the same activity as the fresh after5cycles.VI) Based on the researeh of the catalytic oxidation reaetion kinetics of various typical organic sulfide single component imitation systems, it was determined that the apparent teaction series for level1, and the order of the apparent activation energy of organic sulfide is that DBT>4.6-DMDBT> BT> TH. Probing into the catalytic organic sulfide in desulfurization mechanism by FT-IR, and dynamic monitoring of over-stretching vibration of O-O changes. It was determined that Keggin-type negative ion is firstly oxidized as{PO4[WO(μ-O2)(O2)]4}3-by H2O2, and then electron-rich sulphones were extracted out from oil solution using MeCN as extracting agents.更多还原