Ni-Al类水滑石的制备及其Ni/Al2O3加氢脱硫研究

采用共沉淀方法合成了不同Ni/Al比的镍铝类水滑石,将其作为催化剂前驱体,制备了Ni/Al2O3加氢脱硫催化剂.通过X射线衍射法(XRD),程序升温还原(H2-TPR),热重分析(TG),傅里叶变换红外光谱(FT-IR)等技术对催化剂进行了表征.利用10 mL固定床装置在不同温度,压力,体积空速和氢油比条件下对Ni/Al2O3催化剂的加氢脱硫活性进行了评价.结果表明,XRD图和FT-IR图中均出现了Ni-Al类水滑石的特征峰,TG图呈现出两个明显阶段的失重,在Ni-Al2O3-HT的XRD图中最强的衍射角对应单质金属Ni粒子的(111)晶面.脱硫结果显示Ni-Al类水滑石作为前驱体在适当的条件下,FCC汽油的硫含量降至10 ppm以下.类水滑石作为前驱体的Ni/Al2O3加氢脱硫活性很好,说明类水滑石作为前驱体在加氢脱硫领域有好的应用前景.

Synthesis of Ni/Al2O3 as Hydro-desulfurization (HDS) Catalyst from Ni-Al Hydrotalcite-like Compounds

Conventional hydrodesulfurization (HDS) to convert the sulfur compounds into sulfide was Co-Ni-Mo/Al2O3 or Ni-W/Al2O3 with impregnation method. Impregnation has its shortcomings. It easily leads to the uneven loading and loss of active ingredient. HTLCs as catalyst precursors can be in formation of metal oxides and metal when they are calcined and reduced. It can be noted that the metal oxides and metal derived from HTLCs have a large surface area, well metal particles dispersion, redox and acid-base characteristics, which are good catalysts in catalysis fields. These properties of the metal oxides and metal derived from HTLCs described by literature are well in line with hydrodesulfurization (HDS) catalyst. This article is mainly about HTLCs as a precursor to hydrodesulfurization. We synthesized binary Ni-Al-HT with interlayer CO32- anions and conducted a preliminary study on the desulfurization of Ni-Al-HT as a precursor. The precursors of hydrogen-like structures of Ni-Al-HT catalysts with different Ni/Al ratios have been synthesized by co-precipitation method. The precursors were reduced at about 500oC to get the catalysts. The hydro-desulfurization activity measurements are evaluated at different conditions (temperature, pressure, volume space velocity, H2/oil ratio) in 10 ml catalyst evaluation device. The physic-chemical characteristics of catalysts precursors and catalysts are obtained using X-ray diffraction (XRD), temperature programmed reduction (TPR), Thermal Gravity Analysis (TG) and Differential Thermal Gravity Analyses (DTG) and FT-IR spectra. The XRD patterns and the FT-IR spectra of Ni-Al-HT with different molar ratio confirmed the successful synthesis of catalyst precursors. The reduced Ni-Al2O3-HT was confirmed in the XRD patterns of Ni-Al2O3-HT. The results of catalytic activity measurements showed that the catalysts with HTLCs as precursors have high hydro-desulfurization yield, hydrogen-like precursors have good prospects.