焦炉气加氢催化剂及净化工艺的开发

介绍了适合于焦炉气加氢催化剂及净化工艺的研究实验结果,实验表明,JT-1及JT-8型加氢催化剂均可适用于含高浓度CO和CO2气氛下原料气的加氢净化,且净化度高,副反应小,并满足以焦炉气为原料的甲醇厂的原料净化要求,可将原料气中硫化物脱除至总硫体积分数<0.1×10-6。     

Ultra-deep desulfurization of coker and straight-run gas oils: Effect of lowering feedstock 95% boiling point

Production of diesel fuels with ultra-low-sulfur levels by deep desulfurization of gas oil feeds has received considerable importance in the petroleum refineries in recent years. The type of the gas oil feed and its distillation temperature play a key role in the deep desulfurization process. In the present research project, the effect of lowering the 95% distillation temperature (T₉₅) of two gas oil feeds, namely, straight-run gas oil (SRGO) and coker gas oil (CGO), on deep desulfurization to ultra-low-sulfur levels was investigated. The results showed that for both types of feeds a higher degree of desulfurization was achieved with reduction of T₉₅ from > 360 °C to < 340 °C. The refractory alkyl dibenzothiophenes boiling above 320 °C were present in very low concentrations in the low-boiling cuts and deep HDS to ultra-low-sulfur levels (< 50 ppm) was achieved at low severity operating conditions. Among the two feeds, the CGO that contained high nitrogen content, high concentrations of sterically hindered alkyl DBTs and high aromatics content (low feed saturation) was more difficult to desulfurize than SRGO.     

The functionalities of Pt/γ-Al2O3 catalysts in simultaneous HDS and HDA reactions

A Pt/γ-Al₂O₃ catalyst was tested in simultaneous hydrodesulfurization (HDS) of dibenzothiophene and hydrodearomatization (HDA) of naphthalene reactions. Samples of it were subjected to different pretreatments: reduction, reduction–sulfidation, sulfidation with pure H₂S and non-activation. The reduced catalyst presented the best performance, even comparable to that of Co(Ni)Mo catalysts. All catalyst samples were selective to the HDS reaction over HDA, and to the direct desulfurization pathway of dibenzothiophene HDS over the hydrogenation reaction pathway of HDS. The effect of H₂S partial pressure on the functionalities of the reduced Pt/γ-Al₂O₃ catalyst was studied. The results showed that an increase in H₂S partial pressure does not cause poisoning, but an inhibition effect, without changing the catalyst selectivity. Accordingly, the activity trends were ascribed to adsorption differences between the different reactive molecules over the same catalytic active site. TPR characterization along with a thermodynamics analysis showed that the active phase of reduced Pt/γ-Al₂O₃ is constituted by Pt⁰ particles. However, presulfidation of the catalyst leads to a mixture of PtS and Pt⁰ which has a negative effect on the catalytic performance without changing catalyst functionalities.     

The catalytic activity of Ni/W bimetallic sulfide nanostructured catalysts in the hydrodesulfurization of dibenzothiophene

Two types of catalysts containing NiW bimetallic sulfide nanostructures were prepared by a chemical method employing ammonium thiotungstate and nickel nitrate as metal-sulfide precursors followed by sulfidation in H₂S/H₂ at 400 °C. The nanostructures were grown with excess of Ni, at atomic ratio R = 0.75, 0.85 (R = Ni/Ni + W). High resolution electron microscopy (HRTEM) micrographs revealed the formation of two types of nanostructures, nickel sulfide nanoparticles and long nanorods of tungsten suboxide, both coated by WS₂ layers. The Ni/W catalyst containing mostly nanorods presented twice the catalytic activity (pseudo-zero order constant rate k = 12 × 10⁻⁷ mol/s.g) of the Ni/W catalyst containing nanoparticles (k = 6.3 × 10⁻⁷ mol/s.g) with a low selectivity for tetrahydrodibenzothiophene (THDBT) and high selectivity to cyclohexylbenzene (CHB, 50 mol%). In turn the Ni/W catalyst containing nanoparticles presented a catalytic activity comparable to a Ni/Mo catalyst without inorganic fullerene (IF) nanostructures (k = 7.2 × 10⁻⁷ mol/s.g) but with higher selectivity for hydrogenation to THDBT, (14 mol%) than the sample with nanorods.     

从HDS废催化剂提钒残渣中回收镍的研究

研究了以HDS废催化剂提钒后的残渣为原料制备NiSO4·7H2O的工艺方法,实验结果表明,用浓度为3mol/L、摩尔比为3∶1的盐酸与硝酸混合酸在温度373K下浸取残渣3h,镍提取率可达90%以上。通过调节溶液pH值,可水解除去Al3+、Fe3+、Cu2+,通过加入NaF可除去Ca2+和Mg2+,制得的NiSO4·7H2O样品纯度可达到99%以上。     

Synthesis and characterization of cobalt–molybdenum bimetallic carbides catalysts

Co₃Mo₃C, Co₆Mo₆C and MCM41-supported Co₃Mo₃C catalyst are prepared by a simple one-step thermal decomposition method without the conventional temperature-programmed carburization. The resultant carbides are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and BET surface area measurements. The as-prepared Co₃Mo₃C/MCM41 catalyst exhibits good performance in both probe reactions of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), which proves the one-step decomposition method to be an effective route for the preparation of bimetallic carbide catalyst.     

Genesis of new HDS catalysts through a careful control of the sulfidation of both Co and Mo atoms: Study of their activation under gas phase

Impregnation of oxidic precursor with thioglycolic acid aqueous solution was successfully used to improve the performances of thiophene hydrodesulfurization catalysts. Raman, EXAFS and XPS studies indicate that addition of this chelating agent affects the sulfidation of the supported metals. The higher catalytic performances were attributed to an optimization of the nature and morphology of the active phase obtained by the use of this chelating agent which permits a simultaneous sulfidation of both Co and Mo atoms.     

Synthesis and characterization of P-modified mesoporous CoMo/HMS–Ti catalysts

A hexagonal mesoporous siliceous material with a wormhole framework structure incorporating Ti (HMS-Ti; Si/Ti atomic ratio of 40) was modified with variable amounts of phosphorous and used as support for CoMo phases. The catalysts were prepared by successive impregnation, with Mo being introduced first. The supports and catalysts were characterized by N₂ adsorption–desorption, High-resolution transmission electron microscopy, X-ray diffraction, FT-IR study of the framework vibrations, DRIFT spectra in the OH region, ¹H NMR, FT-IR spectra of adsorbed NO, micro-Raman spectroscopy and X-ray photoelectron spectroscopy. The catalysts were tested in the reaction of hydrodesulfurization (HDS) of dibenzothiophene (DBT) and their activity compared with that of a commercial P-containing CoMo/γ-Al₂O₃ catalyst. The physical and chemical characterization of the P-modified HMS–Ti substrates shows that the presence of P₂O₅ on the support surface does not change its mesoporous character, but modifies its surface properties. In addition, characterization data of the oxide catalysts show that phosphate favors the dispersion of the active phases and increases the population of octahedral Co²⁺ ions associated to Mo species. As a result, HDS activity was strongly enhanced upon P-loading, which reached a maximum of 0.64 wt%. This catalyst is 3.7 times more active than the commercial one and 2.4 times more active than its P-free counterpart. The highest activity of this catalyst was explained in terms of the specific electronic properties of its active phases and the largest Mo surface exposure on the support.     

氮化物对柴油加氢脱硫影响的研究进展

分别从催化剂,工艺条件等方面介绍了氮化物对柴油加氢脱硫反应（HDS）影响的机理。介绍了氮化物对柴油HDS反应影响的动力学研究。结果表明：氮化物对柴油HDS反应具有抑制作用;在不同催化剂活性中心上和不同的工艺条件下氮化物对柴油HDS反应的影响存在差异且符合于拟一级反应动力学。氮化物对柴油HDS的影响研究,可以指导高活性催化剂的开发,寻求最优柴油HDS反应工艺。     

溶胶-凝胶法制备MoP/SiO_2催化剂及其加氢脱硫催化活性的研究

以正硅酸乙酯为硅源,以钼酸铵和磷酸二氢铵为钼源和磷源,采用溶胶-凝胶法,经干燥、焙烧处理后,程序升温还原制备得到二氧化硅负载磷化钼(MOP)催化剂,并以二苯并噻吩为模型化合物,对催化剂的加氢脱硫活性进行初步评价,考察了负载量、反应压力、反应温度等因素对催化活性的影响.结果表明,溶胶-凝胶法制备负载催化剂最佳磷化钼负载量为20%(质量分数);升高反应压力和温度均有利于提高二苯并噻吩的转化率,但降低了产物中联苯的含量.