助剂对WP/γ-Al2O3催化剂性能的影响

 采用浸渍法和H₂气流中磷化还原法制备了一系列负载 30%WO₃和各种不同含量Ni、Co、V助剂的WP/γ-Al₂O₃, 并采用XRD、NH₃-TPD、XPS手段和高压微反装置对它们进行表征和催化活性评价,考察助剂Ni、Co和V对WP/γ-Al₂O₃催化剂物化性质和催化性能的影响. 结果表明, 加入适量的助剂Ni(3%～5%)、Co(5%～7%)和V(1%～3%)能够改善WP/γ-Al₂O₃催化剂表面上活性组分的分散性和增加WP/γ-Al₂O₃催化剂的比表面积. 助剂Ni和Co的加入使WP/γ-Al₂O₃催化剂表面上低价W物种数量增多.而助剂V的加入使WP/γ-Al₂O₃催化剂表面上低价W物种数量减少. 在高温(360℃)下咔唑加氢脱氮(HDN)反应中和低温(300℃)下的二苯并噻吩(DBT)加氢脱硫(HDS)反应中, WP/γ-Al₂O₃催化剂分别具有优良的HDN和HDS活性. 含有更高的DBT的HDS活性. 在较高温度(360℃)下DBT的HDS反应中, 含1%V的V-WP/γ-Al₂O₃催化剂的HDS活性高于WP/γ-Al₂O₃催化剂. 助剂Ni和Co明显促进了WP/γ-Al₂O₃催化剂在咔唑HDN反应中的活性, Ni助剂的助催化作用比Co更明显.含7%Ni的Ni-WP/γ-Al₂O₃催化剂和含5%Co的Co-WP/γ-Al₂O₃催化剂在300℃咔唑HDN反应中HDN活性很高. 加入1%的V可以提高WP/γ-Al₂O₃催化剂在咔唑HDN反应中尤其在360℃下咔唑HDN反应中的HDN活性.

EFFECT OF PROMOTERS ON PROPERTIES OF WP/γ-Al2O3 CATALYST

The WP/γ-Al2O3 catalysts containing 30% mass fraction of W and different mass fractions of promoter Ni, Co and V, respectively, were synthesized by the methods of impregnation and reduction-phosphiding with H2, and characterized by XRD, NH3-TPD and XPS. Their performances of hydrotreating desulfurization and denitrogenation（HDS and HDN）were evaluated in a high pressure micro-reactor. The effects of the promoter Ni, Co and V on physico-chemical properties and catalytic performance of WP/γ-Al2O3 catalyst were investigated. The results indicated that a suitable amount addition of Ni (Mass fraction 3%-5%, the same below), Co(5%-7%) and V(1%-3%) into WP/γ-Al2O3 could increase the dispersity of W species on the support and the BET surface area of the WP/γ-Al2O3 catalyst. The addition of Ni or Co into WP/γ-Al2O3 catalyst could increase the amount of active W species on the surface of catalyst, whereas the addition of V could decrease the amount of active W species. The WP/γ-Al2O3 catalyst possessed a high HDS activity in DBT HDS reaction at lower reaction temperature（300℃）and a high HDN activity of carbazole HDN reaction at higher reaction temperature（360℃）. In DBT HDS reaction the Ni-WP/γ-Al2O3 catalyst with 3%Ni and Co-WP/γ-Al2O3 catalyst with 3%Co had higher HDS activities than WP/γ-Al2O3 catalyst. In DBT HDS reaction at 360℃, the V-WP/γ-Al2O3 catalyst with 1%V possessed higher HDS activity than WP/γ-Al2O3 catalyst. In carbazole HDN reaction at 300℃, Co-WP/γ-Al2O3 and Ni-WP/γ-Al2O3 possessed obviously higher HDN activities than WP/γ-Al2O3 catalyst, in which Ni showed more effect than Co. The Ni-WP/γ-Al2O3 catalyst with 7%Ni and Co-WP/γ-Al2O3 catalyst with 5%Co had high activities in carbazole HDN reaction. The V-WP/γ-Al2O3 catalyst with 1%V had higher HDN activity than WP/γ-Al2O3 catalyst in carbazole HDN reaction, especially at the reaction temperature of 360℃.