Al2O3晶型对Pt/Al2O3-Cl催化剂物化性质及其催化C5/C6异构化性能的影响

以拟薄水铝石粉和湃水铝石粉为前驱体，通过挤条成型和焙烧制备了3种不同晶型(γ、θ、η)Al₂O₃载体，并分别经负载Pt和氯化制备了3种Pt/Al₂O₃-Cl催化剂(Pt/γ-Al₂O₃-Cl、Pt/θ-Al₂O₃-Cl和Pt/η-Al₂O₃-Cl)；采用X射线衍射(XRD)、N₂吸附-脱附(BET)、吡啶红外(Py-IR)、透射电镜(TEM)、NH₃程序升温脱附(NH₃-TPD)等手段表征了3种Al₂O₃载体及Pt/Al₂O₃-Cl催化剂，并通过固定床微反装置考察了Pt/Al₂O₃-Cl催化剂的C₅/C₆异构化性能。结果表明：γ、θ、η型Al₂O₃载体经负载Pt和氯化后，晶型不发生改变，Cl含量和酸量均大幅度提高，Lewis酸酸性显著增强，比表面积和孔体积明显下降；Pt/η-Al₂O₃-Cl催化剂的比表面积和酸量最大，C₅/C₆异构化活性最高，Pt/γ-Al₂O₃-Cl次之，Pt/θ-Al₂O₃-Cl最低；在温度为150 ℃、压力为3.2 MPa、进料质量空速为1.5 h^-1、氢/烃摩尔比为1.0的条件下，Pt/η-Al₂O₃-Cl催化剂作用下，C₅异构化率、C₆异构化率和C₆选择性分别为77.13%、88.68%和31.87%。

Effect of Al2O3 Crystal Phase on Physicochemical Properties of Pt/Al2O3-Cl Catalyst and Its Catalytic Property for C5/C6 Isomerization

Taking pseudo-boehmite powder and bayerite powder as precursors, three kinds of Al₂O₃ carriers with different crystal phases (γ, θ, η) were obtained by calcination of the extruded precursors, and accordingly three kinds of Pt/Al₂O₃-Cl catalysts (Pt/γ-Al₂O₃-Cl, Pt/θ-Al₂O₃-Cl, Pt/η-Al₂O₃-Cl) were prepared through Pt loading and chlorination. In addition, three kinds of Al₂O₃ carriers and corresponding Pt/Al₂O₃-Cl catalysts were characterized by means of X-ray diffraction (XRD), N₂ adsorption-desorption (BET), pyridine infrared spectroscopy (Py-IR), transmission electron microscopy (TEM), and temperature programmed desorption of NH₃ (NH₃-TPD). The catalytic property of Pt/Al₂O₃-Cl catalysts for C₅/C₆ isomerization was investigated by fixed-bed microreactor. The results show that after Pt loading and chlorination, the crystal phases of γ-, θ- and η-Al₂O₃ carriers remain unchanged, both the content of Cl and the amount of acid increase greatly, the acidity of Lewis acid is improved significantly, and the specific surface area and pore volume decrease obviously; Pt/η-Al₂O₃-Cl catalyst has the highest specific surface area, acid amount and C₅/C₆ isomerization activity, followed by Pt/γ-Al₂O₃-Cl and Pt/θ-Al₂O₃-Cl; under the effect of Pt/η-Al₂O₃-Clcatalyst, when meeting the following conditions: temperature 150 ℃， pressure 3.2 MPa， feedstock mass hourly space velocity 1.5 h^-1, hydrogen/ hydrocarbon molar ratio 1.0, the C₅ isomerization rate, C₆ isomerization rate and C₆ selectivity can reach 77.13%, 88.68% and 31.87% respectively.