检索结果-南通市图书馆

Effect of graphene functionalizing on the performance of NiMo/graphene in HDS and HDN reactions

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2019年第5期16卷 1185-1195页

作者： Babak Behnejad Majid Abdouss ahmad tavasoli Department of Chemistry Amirkabir University of TechnologyTehranIran School of Chemistry College of ScienceUniversity of TehranTehranIran

In this research,to remove sulfur and nitrogen compounds from heavy naphtha,various nanocatalysts were prepared through supporting NiMo over nanoporous graphene and evaluated in hydrodesulfurization and hydrodenitrogenation *** nanoporous graphene was initially functionalized in order to facilitate the metal being loaded on *** different methods were used to functionalize the nanoporous *** NiMo/nanoporous graphene nanocatalysts were characterized by field emission scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction,inductively coupled plasma optical emission spectrometry,temperature-programmed reduction,nitrogen adsorption-desorption isotherms and transmission electron microscopy *** performance was evaluated in terms of conversions of sulfur,mercaptans(R-SH)and nitrogen *** was found that the functionalized nanoporous graphene support could significantly enhance the catalytic performance in comparison with the industrial NiMo/alumina *** the functionalized graphene supports,amine-functionalized graphene exhibited the best *** using NiMo supported over amine-functionalized graphene,the conversions of total sulfur and R-SH reached 97.8%and 98.1%,respectively.

关键词： Hydrodesulfurization(HDS) Hydrotreating(HDT) Nanocatalyst Catalyst support Graphene functionalization NiMo/nanoporous graphene

Kinetics and product distribution studies on ruthenium-promoted cobalt/alumina Fischer-Tropsch synthesis catalyst

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2010年第6期19卷 653-659页

作者： ahmad tavasoli Ali Nakhaei Pour Masoumeh Ghalbi Ahangari School of chemistry College of scienceUniversity of Tehran Research Institute of Petroleum Industry

Hydrocarbon production rates and distributions on ruthenium promoted alumina supported cobalt Fischer-Tropsch synthesis （FTS） catalyst were studied by the concept of two superimposed Anderson-Schulz-Flory （ASF） *** results indicated that the characterizing growth probabilities α1 and α2 were strongly dependent on reaction *** increasing the H2 /CO partial pressure ratios and reaction temperatures,deviation from normal ASF distribution decreases and the double-α-ASF distribution changes into a straight *** on the concept of double-α-ASF distribution,a useful rate equation for the production of hydrocarbons under industrial reaction conditions is obtained.

关键词： Fischer-Tropsch synthesis cobalt catalyst ruthenium reaction rate products distribution

Non-catalytic conversion of wheat straw,walnut shell and almond shell into hydrogen rich gas in supercritical water media

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2016年第8期24卷 1097-1103页

作者： Farid Safari Mohammad Salimi ahmad tavasoli Abtin Ataei Department of Energy Engineering Science and Research Branch Islamic Azad University School of Chemistry College of science University of Tehran

Agricultural wastes as lignocellulosic biomasses are known as the major resources of bioenergy. These valuable resources can be converted into useful environmental friendly fuels and chemicals. Wheat straw, walnut shell and almond shell are the main agricultural wastes in Kurdistan province, Iran. This study investigates the hydrogen-rich gas production via gasification of these biomasses in supercritical water media. Experiments were performed first, in the base case condition using a stainless steel batch micro reactor system. Then, the effect of reaction time on the total gas yield and yield of hydrogen, were investigated. It was seen that the total gas yields and gasification efficiencies increased by increasing the reaction time to 30 min and then the total gas yield was approximately remained constant. Among three used feed stocks, wheat straw with higher amount of cellulose and lower amount of lignin had the highest total gas and hydrogen yields in shorter reaction *** maximum hydrogen yields of 7.25, 4.1 and 4.63 mmol per gram of wheat straw, almond shell and walnut shell occurred at 10, 15 and 20 min of reaction time, respectively.

关键词： Hydrogen Biomass Gasification Supercritical water media

Comparing the deactivation behaviour of Co/CNT and Co/γ-Al_2O_3 nano catalysts in Fischer-Tropsch synthesis

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2012年第5期21卷 605-613页

作者： ahmad tavasoli Saba Karimi Somayeh Taghavi Zahra Zolfaghari Hamideh Amirfirouzkouhi School of Chemistry College of ScienceUniversity of TehranTehranIran

An extensive study of Fischer-Tropsch （FT） synthesis on cobalt nano particles supported on γ-alumina and carbon nanotubes （CNTs） catalysts is reported.20 wt% of cobalt is loaded on the supports by impregnation *** deactivation of the two catalysts was studied at 220 C,2 MPa and 2.7 L/h feed flow rate using a fixed bed *** calcined fresh and used catalysts were characterized extensively and different sources of catalyst deactivation were *** of cobalt-support mixed oxides in the form of xCoO yAl2O3 and cobalt aluminates formation were the main sources of the Co/γ-Al2O3 catalyst *** sintering and cluster growth of cobalt nano particles are the main sources of the Co/CNTs catalyst *** the case of the Co/γ-Al2O3 catalyst,after 720 h on stream of continuous FT synthesis the average cobalt nano particles diameter increased from 15.9 to 18.4 nm,whereas,under the same reaction conditions the average cobalt nano particles diameter of the Co/CNTs increased from 11.2 to 17.8 ***,the initial FT activity of the Co/CNTs was 26% higher than that of the Co/γ-Al2O3,the FT activity over the Co/CNTs after 720 h on stream decreased by 49% and that over the Co/γ-Al2O3 by 32%.For the Co/γ-Al2O3 catalyst 6.7% of total activity loss and for the Co/CNTs catalyst 11.6% of total activity loss cannot be recovered after regeneration of the catalyst at the same conditions of the first regeneration *** is concluded that using CNTs as cobalt catalyst support is beneficial in carbon utilization as compared to γ-Al2O3 support,but the Co/CNTs catalyst is more susceptible for deactivation.

关键词： Fischer-Tropsch synthesis cobalt carbon nanotube γ-alumina deactivation

Studies on accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt Fischer-Tropsch synthesis catalyst

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2011年第1期20卷 65-71页

作者： Shohreh Tehrani Mohamad Irani ahmad tavasoli Yadollah Mortazavi Abbas A. Khodadadi Ali Nakhaei Pour Research Institute of Petroleum Industry Department of Chemical Engineering College of Engineering University of Tehran School of Chemistry College of Science University of Tehran

Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt （K-Ru-Co/γ-Al 2 O 3 ） Fischer-Tropsch （FT） synthesis catalyst along the catalytic bed over 120 h of time-on-stream （TOS） was investigated. Catalytic bed was divided into three parts and structural changes of the spent catalysts collected from each catalytic bed after FT synthesis were studied using different techniques. Rapid deactivation was observed during the reaction due to high reaction temperature and low feed flow rates. The physico-chemical properties of the catalyst charged in the Bed #1 of the reactor did not change significantly. Interaction of cobalt with alumina and the formation of CoAl 2 O 4 increased along the catalytic bed. Reducibility percentage decreased by 4.5%, 7.5% and 12.9% for the catalysts in the Beds #1, #2 and #3, respectively. Dispersion decreased by 8.8%, 14.4% and 26.6% for the catalysts in the Beds #1, #2 and #3, respectively. Particle diameter increased by 0.6%, 2.4% and 10.4% for the catalysts in the Beds #1, #2 and #3, respectively, suggesting higher rate of sintering at the last catalytic bed. The amount of coke at the last catalytic bed was significantly higher than those of Beds #1 and #2.

关键词： Fischer-Tropsch synthesis cobalt accelerated deactivation sintering coke formation

Performance enhancement of bimetallic Co-Ru/CNTs nano catalysts using microemulsion technique

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2013年第5期22卷 747-754页

作者： ahmad tavasoli Somayeh Taghavi School of Chemistry College of Science University of Tehran

Bimetallic cobalt-ruthenium nano catalysts supported on carbon nanotubes(CNTs)are prepared using microemultion technique with water-to-surfactant ratios of 0.5—*** nano catalysts were extensively characterized by different methods and their activity and selectivity in Fischer-Tropsch synthesis(FTS)have been assessed in a fixed-bed *** physicochemical properties and performance of the nanocatalysts were compared with the catalyst prepared by impregnation *** narrow particle size distribution has been produced by the microemulsion technique at relatively high loadings of active metals(15 wt%Co and 1 wt%Ru).According to TEM images,small Co particles(2—7 nm)were mostly confined inside the *** with the catalyst prepared by impregnation,the use of microemulsion technique with water to surfactant ratio of 0.5 decreased the average cobalt oxide particle size to 4.8 nm,the dispersion was almost doubled and the reduction increased by 28%.Activity and selectivity were found to be dependent on the catalyst preparation method and water-to-surfactant ratio(as well as cobalt particle sizes).CO conversion increased from 59.1%to 75.1%and the FTS rate increased from 0.291 to0.372 gHC/(gcath).C5+liquid hydrocarbons selectivity decreased from 92.4%to 87.6%.

关键词： Fischer-Tropsch synthesis cobalt ruthenium microemulsion particle size

Fischer-Tropsch synthesis over ruthenium-promoted Co/Al_2O_3 catalyst with different reduction procedures

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2010年第5期19卷 503-508页

作者： Ali Karimi Ali Nakhaei Pour Farshad Torabi Behnam Hatami ahmad tavasoli Mohammad Reza Alaei Mohammad Irani Research Institute of Petroleum Industry (RIPI) Gas Research Division

The effect of reduction procedure on catalyst properties, activity and products selectivity of ruthenium-promoted Co/γ-Al2O3 catalyst in Fischer-Tropsch synthesis （FTS） was investigated. Catalyst samples were reduced with different reduction gas compositions and passivated before being characterized by TPR and XRD techniques. Different activity and product selectivity analyses were also performed. These results showed that the catalyst dispersion, particle size, and the degree of reduction changed with different reduction gas compositions, which were resulted from the water partial pressures in reduction process that give varying degrees of interaction with the support. It has been suggested that the FTS activity of cobalt catalyst was directly dependent on the catalyst reducibility. A reduction gas with a molar ratio of H2Prle = 1 was used to prevent the formation of Co-support compound during catalyst reduction.

关键词： Fischer-Tropsch synthesis cobalt reducibility activity C5+ selectivity

Enhancement of bimetallic Fe-Mn/CNTs nano catalyst activity and product selectivity using microemulsion technique

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2014年第1期23卷 57-65页

作者： Zahra Zolfaghari ahmad tavasoli Saber Tabyar Ali Nakhaei Pour School of Chemistry College of ScienceUniversity of Tehran School of Chemistry Ferdowsi University of Mashhad

Bimetallic Fe-Mn nano catalysts supported on carbon nanotubes(CNTs) were prepared using microemulsion technique with water-to-surfactant ratios of 0.4-1.6. The nano catalysts were extensively characterized by different methods and their activity and selectivity in Fischer-Tropsch synthesis(FTS) have been assessed in a fixed-bed microreactor. The physicochemical properties and performance of the nanocatalysts were compared with the catalyst prepared by impregnation method. Very narrow particle size distribution has been produced by the microemulsion technique at relatively high loading of active metal. TEM images showed that small metal nano particles in the range of 3–7 nm were not only confined inside the CNTs but also located on the outer surface of the CNTs. Using microemulsion technique with water to surfactant ratio of0.4 decreased the average iron particle sizes to 5.1 nm. The reduction percentage and dispersion percentage were almost doubled. Activity and selectivity were found to be dependent on the catalyst preparation method and average iron particle size. CO conversion and FTS rate increased from 49.1% to 71.0% and 0.144 to 0.289 gHC/(gcat h), respectively. While the WGS rate decreased from 0.097 to 0.056 gCO2/(gcat h). C5+liquid hydrocarbons selectivity decreased slightly and olefins selectivity almost doubled.

关键词： Fischer-Tropsch synthesis iron magnesium microemulsion particle size activity product selectivity

Production of hydrogen and syngas via pyrolysis of bagasse in a dual bed reactor

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2013年第4期22卷 639-644页

作者： Morteza Shoja Mokhtar Akhond Babatabar ahmad tavasoli Abtin Ataei Department of Energy Engineering Science and Research Branch of Islamic Azad University Department of Applied Chemistry School of ChemistryCollege of ScienceUniversity of Tehran

Pyrolysis of bagasse followed by thermal cracking of tar was carded out at atmospheric pressure using a dual bed reactor. The first bed was used for the pyrolysis and the second bed was used for thermal cracking of tar. Iron fillings were used as the packed bed material in the second bed. The effects of reaction time （20 to 40 rain）, reactor temperature （600 to 900 ℃） and packed bed height （40-100 mm） on the product （char, tar and gas） yield and gas （H2, CO, CO2, CH4, CnHm） composition were studied. Over the ranges of the experimental conditions used, the operating conditions were optimized for pyrolysis temperature around 850 ℃, a reaction time of 30 min and packed bed height of 100 mm, thus we could obtain a gas richer in hydrogen and carbon monoxide and poorer in carbon dioxide and hydrocarbons. It was observed that compared with single bed process, dual bed process increased the gas yield from 0.397 to 0.750 m3/kg and decreased the tar yield from 0.445 to 0.268 g/g while the heating value of the product gas remained almost constant （10-11 M J/m3）.

关键词： bagasse dual bed reactor hydrogen syngas yield