制备轻油蒸汽转化制氢镍催化剂新的共浸法

用一种新的共浸法制备一批轻油蒸汽转化催化剂样品。运用TG、DTG、DSC和XRD进行的研究发现,与一般共浸法相比,这种着重提高组份间相互作用的新制法有利于提高镍催化剂的活性、抗积炭性、稳定性和金属镍的分散度,并发现用新法制备的催化剂样品,在水热初期约30小时的过程中,出现了镍晶粒先聚集再分散的新现象。     

Differences in the structure of copper active sites for decomposition and selective reduction of nitric oxide with hydrocarbons and ammonia

Cu ion co-ordination-location in zeolites of MFI, erionite, mordenite matrices has been determined and the activity of the individual Cu sites compared for NO decomposition and its selective reduction by hydrocarbons or ammonia. It appears that Cu ions in the vicinity of one framework Al (site II), able to form stable Cu⁺-dinitrosyl complexes, and abundant in MFI structure, are responsible for high activity in NO decomposition. The Cu ions neighbouring two framework Al atoms (site I), and forming mostly mononitrosyl complexes, which dominate in erionite structure, provide a high activity in selective reduction of NO.     

活性炭载体的超声波处理对Pt／C催化剂活性的影响分析

通过对活性炭载体进行不同条件的超声波处理获得了具有不同表面化学性质的载体，使用比表面积（BET）、酸碱滴定等技术手段对载体的物理化学性质进行了表征。将经过超声波处理的活性炭载体制备成Pt／C催化剂，并将催化剂直接用于催化反应，考察了活性炭载体的不同超声波处理条件对Pt／C催化剂性能的影响。实验发现，活性炭载体经过超声波处理后，表面灰分含量、pH值和中孔孔容有较大的变化；使用经过60min超声波处理后中孔孔容较大的活性炭作为载体制备的Pt／C催化剂，在催化加氢反应性能测试中显示了最高的催化活性。在此基础上，就活性炭载体的超声波处理对Pt／C催化剂活性的影响进行了讨论。     

Single and combined deactivating effect of alkali metals and HCl on commercial SCR catalysts

Two commercial SCR catalysts, with a nominal W content of about 9 wt.% and a V nominal content of 0.55 and 1.8 wt.%, respectively, were contacted with different amounts of Na and K and with HCl vapours in order to simulate poisoning by species more specifically contained in exhaust gases from MSW combustion. Catalysts were characterised using XRD analysis, SEM/EDX analysis, BET and pore size distribution measurements, NH₃ TPD, TG analysis. Poisoning agents do not cause loss of surface area nor pore occlusion. A significant loss of surface acidity was observed upon alkali metals poisoning whereas a decreasing of vanadium content was observed for the more concentrated catalysts upon HCl poisoning. Catalysts deactivation is proportional to the number of acid sites neutralised by alkali metals adsorbing ammonia in the temperature range typical of SCR process. HCl promotes the formation of new acid sites showing a lower activity compared to the original one.     

Turnover rates for heptane reforming over Pt/L zeolites with different alkali cations

A series of 0.6 wt% Pt/BaL catalysts with different alkali cations have been tested for heptane reforming at 440 ° C, 0.16 atm heptane, 0.95 atm H₂, 6.7 atm He, 3 to 5 h of reaction, and conversions between 2 and 10%. As the cations in the zeolite are progressively changed from lithium to cesium, the turnover rates for hydrogenolysis and dehydrocyclization increase by about 5–10 times, while the turnover rate for isomerization remains unchanged. Since the turnover rates for hydrogenolysis and dehydrocyclization are similarly affected, exchanging lighter alkali cations for heavier ones increases the aromatics selectivity by a small amount, from 72 to 82%. These results indicate that metal-support interactions have a moderate effect on the heptane reforming activity, but only a weak effect on the selectivity.     

重油催化裂化反应技术的新进展

近十几年来，重油催化裂化技术作为主要的重质油轻质化手段得到了迅速发展，国内外围绕催化裂化装置的提升管反应器也开发了许多新技术。综述了重油催化裂化反应技术的新进展，并对新技术的开发进行了讨论。     

从废钼合金催化剂中提取钼等有价元素方法的研究

ＭｏＣｏＮｉ合金料首先氧化焙烧碱浸出，滤饼再加纯碱焙烧水浸出使钼与钴镍分离，最后用萃取法分离钴镍的工艺流程，对废钼合金催化剂进行了综合回收。采用该工艺流程和生产线分别生产出合格的工业级钼酸钠、氧化钴和氧化镍。     

Zirconium-based intermetallics as heterogeneous catalysts for the fischer-tropsch reaction: I. Zr-Ni-Co catalysts

Alloys of the general formula Zr₅₀Ni_xCO_50-x, where 0 ≦x≧ 50, have been prepared and used in the temperature range 300–400°C, in the pressure range 1–9 barg in a microtubular reactor for the reaction of hydrogen with carbon monoxide to give hydrocarbons. The alloys or intermetallic materials were prepared by argon arc melting, powdered by hydrogen decrepitation and characterised by means of optical microscopy (metallography), scanning electron microscopy with surface analysis and magnetic susceptibility measurements. The selectivity towards higher hydrocarbons increased with (i) increase in the total pressure and (ii) decrease in hydrogen content of the feed gases. The kinetics were found to be of the form: where m = 1.0 ± 0.2 and n = 0. The apparent energy of activation (E_a) lay in the range of 80–130 kJ mole^?1 and there appeared to be a compensation effect between E_a and the pre-exponential factor A. The turnover numbers for the reaction exhibited an activity maximum for alloys of composition around Zr₅₀Ni₄₀Co₂₀ and Zr₅₀Ni₃₀Co₂₀. Magnetic susceptibility measurements indicated that alloys changed their nature from moderately paramagnetic to strongly paramagnetic or even ferromagnetic after use and this is attributed to the conversion of zirconium to zirconium oxide during reaction with the attendant production of free 3d-transition metals. Derived catalysts prepared by air treatment of the hydrogen-decrepitated intermetallics behaved almost identically to the latter materials and gave similar magnetic susceptibility values to used hydrided materials.     

The adsorption characteristics of two Mo sites on a sulfided MoO3/γ-Al2O3 surface

The surface structure of the oxidized and ammonia dissolved MoO₃/-Al₂O₃ samples and the adsorption characteristics of the sulfided samples were investigated by Laser Raman Spectroscopy (LRS) and Low Temperature Infrared Spectroscopy (LTIR) techniques.It was verified that there were two kinds of coordinated unsaturated Mo sites (denoted as Mo_A(CUS) and Mo_B(CUS)) on the surface and the precursors of Mo_A(CUS) and Mo_B(CUS) were Mo(O) and Mo(T), respectively. It was also concluded that Mo_A(CUS) sites could adsorb NO and CO, while Mo_B(CUS) could adsorb CO only. The surface concentration of Mo_A(CUS) might be far smaller than that of Mo_B(CUS).     

Accelerated sintering of PtRh/Al2O3 catalysts in an oxygen periodic pulse flow

PtRh catalysts were prepared by coimpregnation, with chlorine-free precursors of a -alumina. They were sintered at 973 K under a continuous flow of O₂ (1% in Ar or air) or of a flow of Ar into which pulses of O₂ were injected periodically. Under the latter conditions the sintering was significantly accelerated, particularly for a certain value of the period of O₂ pulses.