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Yan P.-H.,Shanxi Institute of Coal CAS Chemistry | Yan P.-H.,University of Chinese Academy of Sciences | Yan P.-H.,National Engineering Laboratory for Indirect Coal Liquefaction | Tao Z.-C.,National Engineering Laboratory for Indirect Coal Liquefaction | And 12 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology | Year: 2013

Three hydrocracking catalysts were prepared by impregnation method with different incorporation manners of Ni/W metals on HY/Al2O3 support. The effect of combination methods on acidity, hydrogenation capability of the catalysts and its hydrocracking performance on FT wax was studied. The balance between hydrogenation performance and cracking performance could be modulated by adjusting the metal-support combination methods. Ni/W pre-impregnated on HY can increase the hydrogenation capability of the catalyst and simultaneously lower the acidity of the support. The results show that the coordination of high hydrogenation capability and low acidity of catalyst can inhibit the formation of secondary cracking on some extent, and increase the selectivity of diesel. While Ni/W metals supported on HY/Al2O3 can achieve a relative balance of hydrogenation and cracking, thus the catalysts have a higher activity and the more flexible ability to modulate reaction.


Meng S.-C.,Shanxi Institute of Coal CAS Chemistry | Meng S.-C.,University of Chinese Academy of Sciences | Wang H.,Synfuels China Co. | Wang H.,National Engineering Laboratory for Indirect Coal Liquefaction | And 10 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology | Year: 2015

The monodisperse SiO2 microspheres with average diameter of 230 nm made by optimized Stöber method were used as core to prepare core-shell structure SiO2@Fe2O3 catalysts with different shell thickness through hydrolysis precipitation. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 physical adsorption and X-ray diffraction (XRD) were used to characterize the size, structure and morphology of catalysts and the effects of different preparation condition on morphology were discussed. The characterization results indicate that SiO2@Fe2O3 catalysts possess obvious core-shell structure and the spherical morphology of catalyst is kept. Iron oxide nanoparticles are attached to the silica surface through hydroxyl-bond and a 2~10 nm thick dense shell is formed. ©, 2015, Science Press. All right reserved.


Yang C.,Shanxi Institute of Coal CAS Chemistry | Yang C.,University of Chinese Academy of Sciences | Zhang C.-H.,Shanxi Institute of Coal CAS Chemistry | Zhang C.-H.,National Engineering Laboratory for Indirect Coal Liquefaction | And 12 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology | Year: 2016

A series of ZrO2 nanoparticles with different particle sizes and different crystalline phases were prepared using coprecipitation and hydrothermal methods. Their physico-chemical properties were characterized by N2 physisorption, XRD, TEM, Raman spectroscopy, XPS, and NH3-TPD techniques. The catalytic performances for syngas conversion were tested at 400℃, 3 MPa, gas hourly space velocity (GHSV) of 500 mL/(gcat·h), and H2/CO/Ar (volume ratio)=5∶5∶1. It was found that syngas can be directly converted into hydrocarbons over ZrO2 nanoparticles. The hydrocarbon products are mainly composed of isomerized olefins, cyclenes, and aromatics. The selectivity of C5+ hydrocarbons is up to 48%. Moreover, the aromatic concentration in C5+ ranges from 30% to 53% depending on ZrO2 structures. It is also found that the monoclinic ZrO2 shows higher activity than the tetragonal one. Monoclinic ZrO2 with larger specific surface area and acid amount show highest CO conversion as well as the yield of target products, but the monoclinic ZrO2 with lager particle size has the higher acid surface density and results in the higher aromatic selectivity. Consequently, acidity is the key factor for CO conversion. And high acid surface density promotes the formation of aromatics but acid amount affects the activity. © 2016, Science Press. All right reserved.


Qiu C.-W.,Shanxi Institute of Coal CAS Chemistry | Qiu C.-W.,University of Chinese Academy of Sciences | Wu B.-S.,Shanxi Institute of Coal CAS Chemistry | Wu B.-S.,National Engineering Laboratory for Indirect Coal Liquefaction | And 6 more authors.
Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology | Year: 2015

Three Co/SiO2 catalysts doped with different amounts of Ru were prepared by incipient wetness impregnation. These catalysts were characterized by N2 physisorption, XRD, H2-TPD, DRIFTS, etc.; their catalytic performance in Fischer-Tropsch (F-T) synthesis was investigated in a micro fixed-bed reactor. The F-T reaction results showed that the Co/SiO2 catalysts doped with Ru exhibit higher CO conversion, higher turnover frequency (TOF), lower selectivity to CO2 and CH4, as well as lower ratio of olefin to paraffin, in comparison with undoped Co/SiO2. FT-IR spectra indicated that the Co-O bond in the as-prepared catalyst is weakened by the addition of Ru, which facilitates the reduction of the Co/SiO2 catalysts; such results are also supported by the H2-TPR profiles and XRD patterns of the reduced catalysts. The main cobalt phase in the reduced catalyst with 0.5% (by weight) of Ru is in a hexagonal close packing (hcp) structure. CO-DRIFTS results revealed that the peak of linearly adsorbed CO is red-shifted by the addition of Ru, suggesting an improvement on the dissociation of adsorbed CO. CO-TPD results showed that the ratio of COads/Cos and CO*/Cos on catalysts surface is increased by the addition of Ru, which may contribute to the decrease of the selectivity to CH4 in F-T synthesis. ©, 2015, Science Press. All right reserved.


Qiu C.,Shanxi Institute of Coal CAS Chemistry | Qiu C.,University of Chinese Academy of Sciences | Wu B.,Shanxi Institute of Coal CAS Chemistry | Wu B.,National Engineering Laboratory for Indirect Coal Liquefaction | And 6 more authors.
Acta Chimica Sinica | Year: 2015

The effects of cobalt particle size are still controversial for whether it influences Fischer-Tropsch synthesis (F-T synthesis) behavior intrinsically. In the F-T synthesis, a large number of different reaction pathways as well as multitude of products does result in many difficulties in the search for the intrinsic causes. The adsorption and dissociation of CO and H2 is a key step for Fischer-Tropsch synthesis. So the effects are trying to be explained by means of exploring the relationship between the adsorbed behavior of CO and H2 and cobalt particle size. In this work, four Co/SiO2 catalysts with different cobalt particle sizes, named 6, 8, 12, 19 nm, were prepared by incipient wetness impregnation using ethylene glycol (EG) and water mixture as a solvent. The catalysts were characterized by N2 physisorption, X-Ray powder diffraction (XRD), transmission electron microscopy (TEM), temperature programmed desorption (TPD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature programmed surface reaction (TPSR), and their Fischer-Tropsch reactivity were tested in a micro-fixed bed reactor. The F-T synthesis test showed that the catalysts with larger cobalt particle size had lower CO conversion, but their apparent Turnover Frequency (TOF) displayed a maximum for the catalyst with cobalt particle size of 8 nm. TPD and DRIFTS results indicated that both the adsorption and dissociation of CO were stronger on smaller cobalt particle, while some of the active sites could be blocked by carbon species on the surface, thus decreased the effective active sites. The adsorption of CO were weaker on larger cobalt particle and the formed C* species were easily desorbed, exhibiting higher CO*/Cos ratio on the surface. Therefore lower activity and higher CO2 selectivity were observed. It is suggested that the catalyst with medium cobalt particle size can produce medium adsorbability of CO and proper amount of COads (surface adsorbed CO) and C* species to balance suitable C/H ratio on the surface, exhibiting higher F-T activity and selectivity. © 2015 Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences.

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