Thermo-economic optimization of solar air heaters with arcuate-shaped obstacles

Journal of Thermal Analysis and Calorimetry - In this study, thermo-economic optimization of single-pass SAHs (solar air heaters) with obstacles of arcuate shape has been carried out. The research...     

Acid Gas Converting to Organosulfur and Hydrogen in Methanol Thiolation Using Alkali Promoted Catalysts: Case Study

Catalysis Surveys from Asia - An acid gas stream was utilized instead of pure H2S as feedstock in the methanol thiolation reaction with Alkali/W/γ-Al2O3 catalysts. The catalysts were...     

Fischer–Tropsch synthesis: evaluation of Gd and Ru promoters effect on Co/<Emphasis Type="Italic">γ</Emphasis>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst at different conditions

In this study, the effect of Ru and Gd promoters on 15Co/\(\gamma\)-Al₂O₃ catalyst in the Fischer–Tropsch synthesis is investigated. The catalysts were synthesized by dry impregnation method and characterized by XRD, adsorption/desorption of nitrogen, TPR, TEM, ICP and XPS analyses. Activity and selectivity of the catalysts were examined in a fixed bed reactor at 210–230 °C with a H₂/CO ratio of 2 and atmospheric pressure. The results showed that the Ru-promoted catalyst has the highest activity and methane selectivity which reduce the chain growth probability. The Gd-promoted catalyst was shown smaller particle size and higher dispersion of cobalt particles in compared with unpromoted catalyst. The smaller particles have more interaction and thus show the lower catalyst reducibility. The presence of Gd in the catalyst cause higher chain growth probability compared to the unpromoted one. The Ru–Gd-promoted catalysts were shown a synergic effect in the catalyst reducibility. Based on the screening of the catalysts in the atmospheric pressure; the unpromoted, 0.1Ru/15Co/Al₂O₃, and 0.1Ru1Gd/15Co/Al₂O₃ catalysts were selected to test at high pressure conditions, which the 0.1Ru1Gd/15Co catalyst showed the highest C₅ ⁺ selectivity (75%) compared with the 0.1Ru/15Co/Al₂O₃ and the unpromoted one.     

The influence of La2O3 and TiO2 on NiO/MgO/α-Al2O3

Summary The effect of La₂O₃ and TiO₂ on product selectivity, methane conversion and coke formation over NiO/MgO/ α -Al₂O₃ catalyst were studied in a simultaneous steam and CO₂ reforming of methane to syngas. La₂O₃ and TiO₂ were added to the catalyst via incipient wetness impregnation and bulk precipitation techniques and catalyst activity was tested in a fixed bed quartz reactor. Results reveal that although the addition of these oxides has no effect on the product selectivity and methane conversion, but can reduce coke formation on the surface of the catalysts as it can enhance the mobility of lattice oxygen anions. The results further show that the catalysts prepared by bulk precipitation technique decrease the coke formation more effectively.     

Determination of the limits of identification and quantitation of selected organochlorine and organophosphorous pesticide residues in surface water by full-scan gas chromatography/mass spectrometry

In this work, we report a reliable method for quantitation and determination of the limits of identification of 14 organochlorine and organophosphorous pesticide (OPP) residues in surface water. The method features the simultaneous identification and quantitation of targeted pesticides and the possibility of identification of any other eluting compounds. The method is based on liquid-liquid extraction (LLE) with a mixture of petroleum ether and dichloromethane (70:30, v/v) followed by gas chromatographic separation and a full-scan mass spectrometric detection (GC-MS). The method presents a new validation parameter, limit of identification (LOI) which is defined for our purpose as the lowest analyte concentration that yields a library searchable mass spectrum. The method is linear over the range 0.048-1.20microgL(-1) for nine pesticides and 0.024-0.60microgL(-1) for the other five pesticides. Correlation coefficients vary between 0.988 and 0.998. Limits of detection (LODs) vary between 0.005 and 0.05microgL(-1) for 4,4'-DDT and LOIs vary between 0.012 and 0.048microgL(-1).