Hydrodenitrogenation and hydrodesulfurization of coal tar on Ni-W catalysts with different metal loadings
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摘要: 以γ-Al2O3为载体, 采用等体积浸渍法制备了五种金属原子比相同而金属负载量不同的Ni-W基催化剂。通过X射线衍射(XRD)、光电子能谱(XPS)、程序升温脱附(NH3-TPD)、氮气吸附、高分辨透射电镜(HRTEM) 等技术对催化剂进行了表征。在固定床反应器中, 以中低温煤焦油为原料, 考察了催化剂的加氢脱氮(HDN) 和加氢脱硫(HDS) 性能。结果表明, 当Ni/W原子比为0.786时, 负载金属后, 催化剂的总酸量减少, 且以中强酸为主。随着金属负载量的增加, 催化剂的硫化程度逐渐增加, HDN活性先增加后降低, 当WO3负载量为24%时达到最优值, 而HDS活性逐渐增强。Abstract: The γ-Al2O3 supported Ni-W catalysts with different metal contents for the hydroprocessing of low and middle-temperature coal tar were prepared and characterized by the X-ray diffractogram (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed desorption of NH3 (NH3-TPD), N2 adsorption and high resolution transmission electron microscopy (HRTEM). The hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) performances of the catalysts were evaluated by using low and middle temperature coal tar. The results show that the sulfidation degree of the catalysts increases with increasing metal content within a certain range, while the amount of total acid that mainly consists of intermediate acid decreases. The HDN activity of the catalysts with Ni/W atomic ratio of 0.786 increases initially and reaches an optimum value at 24% WO3, and then decreases, while the HDS activity increases gradually.
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Key words:
- coal tar /
- hydrodenitrogenation and hydrodesulfurization /
- Ni-W /
- catalyst
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表 1 催化剂的金属含量及配比
Table 1 Metal content and atomic ratio of the catalysts
WO3 w/% NiO w/% Ni/W Ni/(Ni+W) Cat-W16 16 4.05 0.786 0.44 Cat-W20 20 5.06 0.786 0.44 Cat-W24 24 6.07 0.786 0.44 Cat-W28 28 7.09 0.786 0.44 Cat-W32 32 8.10 0.786 0.44 表 2 中低温煤焦油的元素分析
Table 2 Chemical compositions of low and middle-temperature coal tar
Contentw/% C H N S O* 83.05 8.81 0.88 0.27 6.99 *: the oxygen content was calculated by the subtraction method 表 3 载体及催化剂的孔结构
Table 3 Pore structure parameters of the support and catalysts
Catalyst Al2O3 cat-W16 cat-W20 cat-W24 cat-W28 cat-W32 BET surface Area A/(m2·g-1) 256.86 208.46 193.04 182.34 164.56 147.38 Pore volume v/(cm3·g-1) 0.62 0.48 0.44 0.41 0.36 0.33 Average pore diameter d/nm 9.71 9.14 9.04 8.92 8.82 7.81 表 4 载体及催化剂的BJH孔结构分析
Table 4 Pore size distributions of the support and catalysts
d/nm Al2O3 cat-W16 cat-W20 cat-W24 cat-W28 cat-W32 V/cm3 w/% V/cm3 w/% V/cm3 w/% V/cm3 w/% V/cm3 w/% V/cm3 w/% >20 0.126 19.968 0.097 20.083 0.089 20.045 0.085 20.531 0.075 20.270 0.070 21.148 13-20 0.067 10.618 0.053 10.973 0.050 11.261 0.046 11.111 0.041 11.081 0.037 11.178 10-13 0.097 15.372 0.067 13.872 0.057 12.838 0.057 13.768 0.041 11.081 0.035 10.574 7-10 0.163 25.832 0.122 25.259 0.106 23.874 0.095 22.947 0.086 23.243 0.076 22.961 4-7 0.129 20.444 0.097 20.083 0.097 21.847 0.086 20.773 0.086 23.243 0.077 23.263 2-4 0.047 7.448 0.044 9.110 0.042 9.459 0.042 10.097 0.038 10.270 0.034 10.272 <2 0.002 0.317 0.003 0.621 0.003 0.676 0.003 0.725 0.003 0.811 0.002 0.604 表 5 载体及催化剂的酸性分布
Table 5 Acid distributions of the support and catalysts
Catalyst 100-200 ℃ w/% Relative content 200-350 ℃ w/% Relative content 350-550 ℃ w/% Relative content Total relative content Al2O3 4.74 1 43.67 1 51.58 1 1 Cat-W16 7.08 1.18 56.71 1.03 36.21 0.56 0.79 Cat-W20 5.77 0.77 60.42 0.87 33.81 0.41 0.63 Cat-W24 3.25 0.44 55.19 0.81 41.56 0.52 0.64 Cat-W28 5.61 0.58 57.49 0.80 36.90 0.45 0.61 Cat-W32 4.51 0.72 48.27 0.83 47.22 0.69 0.75 表 6 硫化态催化剂W和Ni的结合能和硫化程度
Table 6 Binding energy and sulfidation degree of W and Ni of the catalysts after sulfidation
Catalyst cat-W16 cat-W20 cat-W24 cat-W28 cat-W32 WS2 EB 4f7/2/eV 32.50 32.50 32.50 32.50 32.50 relative content w/% 34.51 38.59 47.77 50.27 51.97 WO3 EB 4f7/2/eV 35.90 35.90 35.90 35.90 35.90 relative content w/% 35.01 22.81 18.27 16.52 10.54 NiS EB 2p3/2(eV) 854.2 854.2 854.2 854.2 854.2 relative content w/% 20.27 26.48 28.51 39.61 43.36 NiO EB 2p3/2/eV 856.2 856.2 856.2 856.2 856.2 relative content w/% 79.73 73.52 71.49 60.39 56.64 表 7 GC-MS对煤焦油原料及加氢产物的分析
Table 7 Analysis of coal tar and hydrogenation products with GC-MS
Composition Coal tar cat-W16 cat-W20 cat-W24 cat-W28 cat-W32 Alkane 22.93 25.08 23.78 26.92 27.25 24.79 Cycloparaffin 0.64 18.27 19.62 14.44 19.14 19.57 Benzene 3.04 17.70 15.33 14.82 13.66 19.08 Phenol 31.45 0.59 0.57 0.53 0.71 1.62 Naphthalenes 18.71 23.34 23.09 22.55 23.04 19.36 Indene 2.62 7.25 8.45 11.51 9.34 8.06 Fluorene 2.67 1.99 2.02 1.94 2.34 2.00 Dibenzofuran 7.60 2.00 1.96 1.97 2.28 2.03 Anthracene phenanthrene pyrene 8.47 2.60 2.93 3.10 2.23 2.95 Else 1.83 1.18 2.25 2.22 0.01 0.54 Grand total 100.00 100.00 100.00 100.00 100.00 100.00 -
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