Applied Petrochemical Research (v.6, #1)
Effect of the Ni/Al ratio of hydrotalcite-type catalysts on their performance in the methane dry reforming process by F. Touahra; M. Sehailia; W. Ketir; K. Bachari; R. Chebout; M. Trari; O. Cherifi; D. Halliche (1-13).
Hydrotalcite-type solids of the form NiAl-R, where R refers to the ratio of Ni to Al (R = 2, 3, 5, 8, and 10), were successfully synthesized following co-precipitation method at pH = 12. The obtained solids were calcined at 800 °C, except for NiAl-R 2 where calcination was performed at temperatures ranging between 300 and 800 °C. Following calcination, the resulting materials were evaluated for their catalytic activity and stability during the process of dry reforming of methane. Factors affecting the catalytic activity of the obtained materials such as the ratio R and calcination temperature were also studied. Prior to calcination, X-ray diffraction analyses clearly illustrated the typical hydrotalcite structure of the synthesized materials (when R ≤ 5). On the other hand, calcination at various temperatures prompted decomposition of all solids to form NiO, with exception to NiAl-R 2, which upon calcinations at 800 °C was decomposed to form NiO and a second phase spinel containing NiAl2O4. The chemical composition of the obtained solids was determined by atomic absorption spectroscopy. Further characterization was performed using several techniques, including: surface area measurements (S BET), scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The reducibility of nickel species was studied via temperature-programmed reduction. The catalytic performance of the as-prepared samples was studied for dry reforming of methane under atmospheric pressure at temperatures ranging between 400 and 700 °C. The catalytic activity of the designed substances highlighted the importance of molar ratios i.e. Ni2+/Al3+ on the success of the overall dry reforming of methane process. The catalytic activity of the synthesized materials was also found to be directly proportional to the ratio of Ni/Al as well as the calcination temperature, with exception to NiAl-R 2 which was found to exhibit the highest activity of all. The latter observation was perhaps associated with the lower size of the crystalline particles in conjunction with the presence of a second phase containing NiAl2O4. In this study, it is shown that the calcination temperature has a significant effect on the catalytic property and the crystallite size of the metal.
Keywords: Dry reforming of methane; Hydrotalcite-like compound; Nickel; Hydrogen
Nitrobenzene hydrogenation over Ni/TiO2 catalyst in vapour phase at atmospheric pressure: influence of preparation method by Mohan Varkolu; Venkateshwarlu Velpula; Ramudu Pochamoni; Ashok Raju Muppala; David Raju Burri; Seetha Rama Rao Kamaraju (15-23).
Highly dispersed nickel nanoparticles on supports such as ZrO2 and TiO2 were prepared by reductive deposition method using hydrazine as reducing agent and applied to nitrobenzene hydrogenation. The highlight of this work is to compare the characteristics and activity of these catalysts with the catalysts of the same composition prepared by impregnation method. All the catalysts were characterized by various techniques such as BET, H2 pulse chemisorption, TEM, XRD (crystalline nature), reduction behaviour (TPR) and state of nickel species (XPS). Ni/TiO2 catalyst prepared by reductive deposition method shows excellent conversion of nitrobenzene (99 %) to aniline. This is due to the presence of higher number of surface Ni species than other catalysts as evidenced by H2-chemisorption. TPR results reveal the formation of metallic Ni species in the reductive deposition method. XRD results suggest that the all catalytic systems show peaks corresponding to the supports only and not due to the metallic Ni because of its presence in highly dispersed form. The decrease in catalytic performance is observed during the time on stream might be due to coking of the catalyst by the reaction intermediate.
Keywords: Reductive deposition method; Hydrazine; Ni/TiO2 ; Nitrobenzene; Aniline
Simulation of hydrodesulfurization unit for natural gas condensate with high sulfur content by Javad Alaei Kadijani; Elhameh Narimani (25-34).
The natural gas condensates are composed of various components of hydrocarbons and some contaminants such as hydrogen sulfide, thiols (mercaptans), and aromatics. Thus, the natural gas condensates could be considered as a fuel resource. This study concerned the simulation of an Ultra-Deep Hydrodesulfurization (UDHDS) unit plus a distillation section to treat a combination of gas condensate and disulfide oils (DSO) and produce clean fuel cuts. Gas condensate of South Pars field of Iran with high sulfur content was applied to obtain clean fuel cuts. In order to reduce the sulfur content of this stream to less than 10 ppmw as sulfur, a UDHDS unit was simulated using Aspen HYSYS software package. The clean gas condensate leaving the UDHDS unit (with sulfur content <10 ppmw) contains complex mixtures of hydrocarbon components called petroleum cuts which are identified by their boiling points ranges. To obtain the narrow fractions of butane, light naphtha, heavy naphtha, kerosene, and gasoil, a fractional distillation system was simulated. The simulation results revealed that the top products of distillation column, namely butane, light naphtha, and heavy naphtha were sulfur free and the sulfur contents of kerosene and gasoil cuts were 12 and 27 ppmw as sulfur, respectively.
Keywords: Gas condensates; Disulfide oils; Sulfur content; Ultra-Deep Hydrodesulfurization unit; Petroleum cuts; Fractional distillation system
The performance of benzenesulfonic acid catalyst on the alkylation of thiophenic sulfur by Zhibing Shen; Juntao Zhang; Tao Ren; Shengrong Liang (35-40).
Catalytic performance of benzenesulfonic acid was investigated for alkylation of thiophenic sulfur compounds with diene. The alkylates were confirmed by gas chromatography–mass spectrometry technique. The reaction conditions were optimized as follows: temperature is 85 °C, catalyst/feed weight ratio is 10 % and time is 80 min. Under the conditions, the conversion of thiophene was nearly 73 %. The catalyst exhibited some recycle-use performance. The catalytic activity could be maintained by addition of the fresh catalyst periodically and quantitatively.
Keywords: Desulfurization; Thiophene; Alkylation; Gasoline; Benzenesulfonic acid
Effects of zinc incorporation on hierarchical ZSM-11 catalyst for methanol conversion by Xiaojing Meng; Chen Chen; Jianwei Liu; Qiang Zhang; Chunyi Li; Qiukai Cui (41-47).
Hierarchical ZSM-11 and Zn-ZSM-11 catalysts were used in this study. The effects of two methods (direct synthesis and impregnation) of zinc incorporation on methanol conversion were investigated in a continuous-flow isotherm fixed-bed reactor. XRD, SEM, BET, FTIR, and XRF analytical results revealed that the introduction of zinc through direct synthesis generated new Brønsted acid sites that could tune the ratio of light olefins. The damage to the framework structure after zinc incorporation restrained the aromatization, dehydrogenation, and decomposition of methanol. The extent of this impact determined the degree of deactivation behaviors. Thus, the yield of propene and butene was enhanced through the direct synthesis method (2 % ZnZ11-C, 4 % ZnZ11-C), and the sample 4 % ZnZ11-C displayed a fast deactivation.
Keywords: Hierarchical ZSM-11; Methanol; Zinc; Acid site; Structure damage
Preparation, characterization, and evaluation of some ashless detergent/dispersant additives for lubricating engine oil by Nehal S. Ahmed; Amal M. Nassar; Hamdy S. Abdel-Hameed; Ahmed F. El-Kafrawy (49-58).
In the present work, different ashless detergent/dispersant additives were prepared via reaction of different primary amines with propylene oxide, and the products which obtained were reacted with different organic acids. The structures of the prepared compounds were confirmed using fourier transform infrared spectroscopy (FT-IR), Proton nuclear magnetic resonance (1HNMR), and gel permeation chromatography (GPC) for determination of molecular weight. All the prepared compounds were found to be soluble in lubricating oil. The efficiency of the prepared compounds as antioxidants and detergent/dispersant additives for lubricating oil was investigated. It was found that the additives have excellent power of dispersion, detergency, and the most efficient additives as antioxidant those prepared by using di-n-butyldithio phosphoric acid.
Keywords: Lubricating oil additives; Ashless detergents and dispersants; Antioxidants; Propylene oxide
Synthesis of diacyl amino acid surfactant and evaluation of its potential for surfactant–polymer flooding by Hongmei Ren; Changxin Shi; Shemin Song; Qingqiao Zeng; Yuzhen Zhang (59-63).
Diacyl amino acid surfactant was prepared using lauroyl chloride and l-lysine. The structure of the synthesized surfactant was confirmed by infrared spectroscopy and mass spectroscopy. The ultralow interfacial tension could be achieved when the diacyl amino acid surfactant is mixed with sulfonate in the presence of polymer as well as absence of polymer. Core flood experiments showed that 17.8 % additional oil could be recovered by injection of 0.3 pore volume of surfactant–polymer solution, making the total oil recovery reach 66.1 %.
Keywords: Synthesis; Diacyl amino acid surfactant; Ultralow interfacial tension; Flooding
Chromatographic study of the recovered gases from hydropyrolytic de-polymerization of LDPE, MDPE and HDPE mix type of waste polyethylene by Gautam Kumar Roy; Bipin Kumar; Swatantreshwar Jha (65-72).
The thirst of energy is one of the biggest challenges the world is facing today. The search for new alternative and renewable source of energy is being studied worldwide. The emission of harmful gases such as NO x , SO x , CO and CO2 and other greenhouse gases in the environment contributes to the global warming and also causes health related problems. Polyethylenes are substances which take longer time for its decomposition and are one of the biggest threats to the environment. The waste polyethylene was thermally de-polymerized and during such process the gases recovered were studied. The study was carried out on low-medium and high-density polyethylene mix. The study of the waste polyethylene into useful hydrocarbon products provides scope for further investigation on this field for the production of domestic fuel. The comparisons of the recovered gases with the LPG gas components were also studied and there fuel property is discussed. This paper describes the gaseous hydrocarbon components recovered during the process of thermal degradation of polyethylene. The component recovered and their importance as fuel is also studied.
Keywords: Polyethylene; De-polymerization; Hydrocarbon; Fuel gas; Gas chromatograph
Catalytic functionalities of nano Ru catalysts supported on TiO2–ZrO2 mixed oxide for vapor phase hydrogenolysis of glycerol to propanediols by Vanama Pavan Kumar; Jorge N. Beltramini; Samudrala Shanthi Priya; Amirineni Srikanth; Ponnala Bhanuchander; Komandur V. R. Chary (73-87).
Vapor phase hydrogenolysis of glycerol was studied over Ru catalysts supported on TiO2–ZrO2 binary oxide. Ru catalysts with various ruthenium loadings from 1.0 to 6.0 wt% were prepared by deposition–precipitation method on the TiO2–ZrO2 mixed oxide support. These catalysts were characterized by X-ray diffraction, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, transmission electron microscopy, BET surface area, XPS and CO chemisorption measurements. The catalysts exhibited superior performance for the vapor phase hydrogenolysis of glycerol at moderate temperature and atmospheric pressure. The mixed oxide support plays a significant role in improving the catalytic activity for the production of propanediols. The glycerol conversion and the selectivity of various products depend on the catalyst preparation method and also on the Ru content. The influence of acidity of the catalyst and its correlation to the catalytic performance (selectivity and conversion) has been studied. The weak and strong acidic sites of the catalysts measured by NH3-TPD play a key role in selective formation of 1,2-propanediol and 1,3-propanediol. XRD, TEM, XPS and CO chemisorption studies revealed that ruthenium was well dispersed on TiO2–ZrO2 which further contributed to the superior catalytic activity for glycerol hydrogenolysis.
Keywords: Glycerol hydrogenolysis; Ruthenium; Titania–Zirconia; 1,2-Propanediol; 1,3-Propanediol
Synthesis of TiO2 with diverse morphologies as supports of manganese catalysts for CO oxidation by Khadidja Hedjazi; Runduo Zhang; Rong Cui; Ning Liu; Biaohua Chen (89-96).
The catalytic CO oxidation reaction has been investigated over a series of Mn/TiO2 catalysts. The titanium dioxides, including several mesoporous structures were prepared by different synthesis procedures. The mesoporous TiO2 synthesized using evaporation-induced self-assembly (EISA) method exhibited the highest surface area (217.14 m2/g). The successful loading of the active manganese component (2 %) to TiO2 supports showed high dispersion of MnO x species in amorphous state. Characterizations of XRD, N2 adsorption–desorption, pore size distributions, TEM, H2-TPR and XPS were applied to contrast their structure properties and correlated with the corresponding catalytic performance. The Mn/EISA exhibited the highest catalytic activity among the series of Mn/TiO2 catalysts, which could completely oxidize CO into CO2 at temperature as low as 270 oC, due to its highly ordered mesoporous channels, which effectively enlarge the surface area leading to promoting a strong interaction between MnO x species (68 % Mn3+) and TiO2 support.
Keywords: Mesoporous; Anatase; Rutile; MnO x ; Oxidation