Mohammad Ashraf Ali

A comparison between β- and USY-zeolite-based hydrocracking catalysts

Abstract Two series of zeolite-based hydrocracking catalysts were prepared to study the effects of the support type, preparation method and metal loading on catalyst properties and hydrocracking activity for hydrotreated vacuum gas oil (HT-VGO). The support used was γ-Al2O3 and β-zeolite in the first series and γ-Al2O3 and USY-zeolite in the second series. Nickel and tungsten were loaded as active metals on these supports. The prepared catalysts were characterized as to their surface area, pore volume, thermal stability, reducibility and acidity characteristics. The characterization results revealed that catalysts displayed significant differences in properties dependent on the preparation method and the type of support used. Catalysts from both series showed promising results for HT-VGO hydrocracking in the batch reactor. A correlation exists between the reducibility of oxidic form and the hydrogenation activity of the sulfided form of the catalysts. The higher the reducibility, the higher the hydrogenation activity. Catalysts prepared on mixed supports gave higher amounts of saturates.

Pulsed laser-induced photocatalytic reduction of greenhouse gas CO2 into methanol: A value-added hydrocarbon product over SiC

CO2 was converted into value-added hydrocarbons (methanol) by laser-induced photocatalytic reduction of CO2 over commercially available silicon-carbide (SiC) granules as catalyst. The conversion of CO2 was carried out in a glass reactor having quartz window and equipped with stirring system and was provided with continuous CO2 flow at ambient conditions. Laser radiations of 355 nm, which were generated by third harmonics of Nd:YAG laser (1060 nm) were applied as an excitation source. The methanol yield as a function of irradiation time and catalysts dosage were monitored by the gas chromatographic analysis (GD-FID) of water samples collected at prescribed intervals. A specific GC column was used which separated hydrocarbons efficiently without any interference from water present in the sample. The study indicated that the commercially available SiC granular material is an excellent catalyst in laser-induced photocatalytic conversion of CO2 into high value hydrocarbons.

Hydrocarbon group types analysis of petroleum products: A comparative evaluation of HPLC and TLC analytical performance

ABSTRACT Four petroleum samples representing a range of hydrocarbon composition were analyzed using the HPLC and TLC–FID techniques that provided separation and quantitation of saturates, aromatics, polars (resins) and asphaltenes. The results obtained from the two methods, for residues and crude oil samples, were not comparable because these samples contain high amount of polars and asphaltenes whereas VGO shows a very good comparison between the results obtained from the two techniques because of its asphaltenes-free and low polar composition. TLC–FID separation required a number of solvents while in HPLC, only one type of solvent was used. In TLC method, a number of samples can be analyzed simultaneously while in HPLC, only one sample is analyzed at a time. HPLC system analyzes a large number of sample in a complete automated fashion without operator involvement while the TLC method needs more involvement and attention of the operators. In HPLC, the aromatics can be further classified based on number of rings while in TLC–FID, aromatics were detected as one peak. The reproducibility of TLC–FID analysis for individual fractions was found good.

Sol–Gel Synthesis of

A facile single-step method was adopted to synthesize gold-modified copper-doped titania nanocomposites. Physicochemical properties of the synthesized material were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy, photoluminescence (PL), and TEM-based techniques. Our characterizations show that the material consisted of anatase-phase qausi-spherical titania nanoparticles (NPs), with 3-4-nm gold particles anchored on titania surface. According to diffuse UV-visible spectroscopic analysis, gold-modified copper-doped titania shows enhanced absorption in the visible-light spectrum compared with copper-doped titania and pure titania. Furthermore, a decrease in PL emission intensity is observed, and this is due to decreased electron-hole recombination, which is an attribute desired for the enhancement of photocatalytic activity. Our present results highlight that these nanocomposites could be used as a photocatalyst for various applications in conjunction with visible solar radiation. The surface modifications make this material for many applications such as gas sensing and photodetection.

\hbox{Au/Cu-TiO}_{2}

The dynamic performance of a power system has been investigated with static synchronous series compensator (SSSC) control. The strategy has been implemented through a PID controller, parameters of which are tuned through an artificial bee colony (ABC) optimization procedure. The small signal response of the system has been evaluated through a 5th order system dynamic model with and without the PID model incorporated. A simple pole-placement technique was employed to get the range of parameters used as input to the ABC algorithm. It was observed that the PID controller, with controller gains determined through ABC algorithm, provided very good transient profile following large disturbances in the system.

Nanocomposite and Their Morphological and Optical Properties

Gold and Copper tailored titania (Au/Cu/TiO2) nanocomposites were synthesized by a modified sol gel method and their morphology and optical properties were studied using various techniques. XRD patterns confirmed the presence of pure anatase phase of TiO2, and an enhanced visible response was found in the absorption spectrum of gold modified Cu/TiO2 and Au/Cu/TiO2 nanocomposites. These doped nanoparticles exhibited low photoluminescence emission intensity which is better for enhancement of photocatalytic activity as discussed. In addition, qausi-spherical morphology of nanoparticles was observed in Field Emission Scanning Electron Microscopy (FE-SEM) images. These nano-engineered materials could be applied in various applications such as energy harvesting surfaces like solar cells, hydrogen production using water splitting, CO2 conversion into value added products like methanol for fuel cells, waste water treatment by degradation of organic and inorganic pollutants and disinfection of water, and last not least as optical sensors.