【作者】 刘章勇；

【导师】 张玉贞；

【作者基本信息】 中国石油大学 ， 化学工程与技术， 2010， 博士

【摘要】 本课题重点研究了反应-吸附作用下渣油加氢脱金属(HDM)反应机理,初步探索了辽河常渣、塔河减渣在该效应下HDM反应行为。利用X射线衍射光谱(XRD)、扫描电镜(SEM)、X射线能谱(EDX)、透射电镜(TEM)、吡啶-红外光谱(Py-IR)、波长色散X射线荧光光谱(XRF)、紫外-可见光谱(Uv-vis)等表征手段对所制备催化剂、HDM反应机理及辽河常渣、塔河减渣中金属分布及存在形态进行研究。高岭土由于价格低廉目前成为研究热点。Py-IR分析得出,酸碱洗改性后高岭土L酸较强,其次是L酸和B酸混合酸,最弱的是B酸;酸碱洗改性后高岭土吸附-脱附等温线呈标准Ⅳ型,带有B型滞后回环。实验发现,当高岭土煅烧温度在600℃时,酸洗有利于高岭土中铝的溶出;煅烧温度在900℃时,碱洗后有利于硅的溶出;酸碱洗改性后时间越长,得到的高岭土孔径越小,比表面积越大。酸改性、负载镍和负载钼的酸改性高岭土对卟啉镍和卟啉钒的吸附符合Langmuir吸附等温线,表明卟啉镍和卟啉钒单层吸附在改性高岭土上。实验发现吸附剂酸性大,吸附金属卟啉量多。同样吸附剂,对卟啉钒的吸附量大于对卟啉镍的吸附量。酸改性、负载镍和负载钼的酸改性高岭土对卟啉镍和卟啉钒的吸附表现为自发放热过程,属于化学吸附。酸改性、负载镍和负载钼的酸改性高岭土对卟啉镍和卟啉钒的吸附遵循拟一级吸附动力学方程所描述的规律。试验发现NiOEP和VOOEP加氢脱金属反应过程中有中间产物卟啉酚的出现,说明HDM反应过程中,金属卟啉先加氢生成卟啉酚,然后氢解脱除金属;硫化物和氮化物对HDM反应作用不同,硫化物起促进作用,而氮化物则有抑制作用;但是硫化物(噻吩)浓度只有达到3100?g/g后,才能够对HDM反应有明显促进;而氮化物(喹啉)则比较敏感,加入微量可使脱金属率大大降低,加入量在490?g/g时,抑制作用达到最大。金属卟啉的HDM反应是连串反应;使用未予化硫化催化剂时,金属卟啉在HDM反应过程中生成金属卟酚和金属卟酚脱金属都是一级反应,使用予硫化催化剂时,则都是二级反应;使用未予硫化催化剂时,镍卟啉生成镍卟酚是整个HDM反应的控制步骤,而对于钒卟啉的HDM反应,钒卟酚脱金属反应则是控制步骤;使用予硫化催化剂时,镍卟酚和钒卟酚脱金属反应是整个反应的控制步骤;用硫化催化剂能够大大降低反应活化能,提高反应速度。反应-吸附作用下对辽河常渣、塔河减渣HDM反应行为和金属分布及存在形态进行研究。辽河常渣中镍主要分布在胶质中,饱和分中没有发现金属镍的存在;塔河减渣中镍和钒主要分布在正庚烷沥青质中。辽河常渣和塔河减渣中的金属卟啉主要以初卟啉ETIO为主;不排除辽河常渣中镍卟啉以脱氧叶红初卟啉DPEP形式的存在,不可能以玫红卟啉RHODO形式存在。随着反应温度升高,辽河常渣HDM反应产物中镍在丙酮可溶物和丙酮不溶物中收率降低,而在正庚烷萃取物中的收率升高。塔河减渣HDM反应产物中金属主要存在于正庚烷和苯萃取物中,这说明越重组分中的金属越难脱除。更多还原

【Abstract】 The study focused on the residue hydrodemetallation (HDM) reaction by reaction-adsorption and researched preliminarily reaction behavior of LiaoHe Atmospheric Residue (LHAR) and TaHe Vaccum Residue (THVR). The as-prepared catalyst, HDM mechanism, as well as the distribution and existing form of nickel (Ni) and vanadium (V) were investigated by X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray energy spectrum(EDX), pyridine adsorption fourier-transform infrared (Py-IR), wavelength dispersive X-Ray fluorescence analysis (XRF) and ultraviolet visible absorption spectroscopy (Uv-vis), respectively.Kaolinite has been a research focus due to its lower price. From Py-IR, the strongest acid is L acid, followed by the mixture of L and B acids, and the lowest acid is B acid when kaolinite was modified by acid and alkali. Adsorption and desorption isotherm of modified kaolinite showed theⅣtype, and the hysteresis loop indicated the B type. The research demonstrated that acid modification was benefitial for aluminum leaching at kaolinite calcination temperature of 600℃and alkali modification was benefitial for silicon extraction at kaolinite calcination temperature of 900℃. The pore diameter became smaller and the surface area became larger as acid and alkali modification time was prolonged.The adsorption process of modified kaolinite adsorbing VOOEP and NiOEP followed the law of Langmuir adsorption isotherm, which indicated that monolayer VOOEP or NiOEP was adsorbed on modified kaolinite; the adsorption quantity increased with enlarging acid strength. The quantity of VOOEP was bigger than the amount of NiOEP using the same adsorbents. The adsorption of metallporphyrin was exothermic in nature and chemical bonds existed between metallorphyrin and modified kaolinite. The adsorption kinetics followed the law of pseudo-first order kinetic mode when modification kaolinite adsorbed metallporphyrin.It was found that intermediate metal porphyrin phenol (MH2) existed during HDM reaction, which showed the reaction sequence, firstly being the hydrogenation of metalporphyrins to metal hydroporphyrins, secondly being the hydrogenolysis of metalhydroporphrins and then resulted in demetallation. Nitrogen and sulfur compounds had great effect on HDM reaction. Nitrogen compounds could inhibit HDM reaction, while sulfur compounds could accelerate HDM reaction, but nitrogen and sulfur compounds coud not change the HDM reaction sequential mechanism. Only when the concentration of sulfur compounds thiophene reached 3100?g/g, would they obviously promoted HDM reaction. The nitrogen compound quinoline had a sensitive effect on HDM reaction. Even small amount could generate large inhabit effect. When the amount of quinoline was 490?g/g, the inhabit effect reached the maximum.The hydrodemetallation(HDM) reaction of metalporphyrin followed a consecutive reaction. The reactions of metal porphyrin forming porphyrin phenol and porphyrin phenol demetallation were first-order reaction, while NiOEP generating NiPH2 and VOOEP generating VOPH2 were the controlling steps when presulfurazation catalyst was used. The reactions of metal porphyrin forming porphyrin phenol and porphyrin phenol demetallation showed as second-order reaction when non-presulfurazation catalyst was used. The experiment found that the activation-energy could be decreased and reaction rate could be increased when presulfurazation catalyst was used.HDM reaction behavior and the metals distribution and existing form of LHAR and THVR were researched by reaction-adsorption. Nickel in LHAR existed mainly in resin and almost no nickel was found in saturate. Nickel and vanadium distributed mainly in heptane asphaltene. Nickel porphyrin in LHAR, Nickel porphyrin and vanadium phorphyrin in THVR mainly were ETIO types, and Nickel porphyrin in LHAR probably existed in DPEP type, and there was probably no RHODO type. As the reaction temperature increased, nickel content decreased in acetone solution and acetone insolution of HDM reaction products of LHAR, but nickel content increased in heptane extract. The metallic compounds of HDM reaction product of THVR were mainly in heptane and benzene extract, which indicated the metallic compounds in heavy components were difficult to remove.更多还原