Ni_2P/Ti-MCM-41的催化加氢脱硫性能

Hydrodesulfurization Performance of Ni_2P/Ti-MCM-41 Catalyst

以MCM-41和Ti-MCM-41介孔分子筛为载体,低温还原法(400℃)制备了磷化镍催化剂。采用XRD、BET、FT-IR、Py-FT-IR、XPS、CO吸附等手段对催化剂进行了表征。采用固定床反应器,以二苯并噻吩为模型化合物,评价了磷化镍催化剂的加氢脱硫催化性能。结果表明,金属Ti的引入可以增强载体和催化剂的B酸和L酸酸性;金属Ti因其电子助剂的作用,能够促进更细小尺寸的Ni_2P活性相的形成。在反应温度340℃、反应压力3.0 MPa、质量空速(MHSV)3.5h^(-1)、V(H_2)/V(Oil)=650的条件下,Ni_2P/Ti-MCM-41催化二苯并噻吩加氢脱硫反应的转化率高达99.38%,与相同条件下制备的Ni_2P/MCM-41相比,提高了约17百分点。Ni_2P/Ti-MCM-41催化剂具有更优的原料处理能力和更佳的催化活性的原因可归结为金属Ti的电子效应、活性相的尺寸和分散度以及催化剂适宜的酸性。

Ni2 P/MCM-41 and Ni2 P/Ti-MCM-41 catalysts were successfully prepared by temperature programmed reduction method at a low reduction temperature（400℃）. The obtained catalysts were characterized by XRD, BET, FT-IR, Py-FT-IR, XPS, TEM and CO uptake. The catalytic hydrodesulfurization（HDS） performance of Ni2P/Ti-MCM-41 was investigated on a fixed bed and with dibenzothiophene（DBT） as model compound. The results indicated that the introduction of Ti into MCM-41can modify the acidic nature of supports and catalysts and enhance the Lewis acidity as well as the Br^nsted acid intensity of supports, being beneficial to the formation of Ni2P active phase because of the electronic properties of Ti. At the conditions of 340℃, 3.0 MPa, mass hourly space velocity （MHSV） of 3.5 h-1 and H2/oil volume ratio of 650, catalyzed by Ni2P/Ti-MCM-411 the conversion of DBT HDS reached 99.38%, 17% higher than that catalyzed by Ni2P/MCM-41 catalyst. The electronic effect of Ti, size of active phase and its dispersion, and the moderate surface acidity of catalyst may be responsible to the enhancement of HDS catalytic activity of the Ti-doped samples.