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It is aimed to develop SBA-15 supported Ni catalysts with Zr incorporation that can reduce carbon formation for synthesis gas production via dry reforming methane. In this study, Zr-containing SBA-15 support materials were synthesized following a one-pot hydrothermal synthesis method in three different synthesis conditions using HCl (A), NaCl (S) and both HCl and NaCl (B). Ni catalysts containing Zr-SBA-15 support materials were prepared by an impregnation method. Zr-SBA-15 prepared under different synthesis conditions supported Ni catalysts were tested in dry reforming of methane at 750℃. All catalysts were characterized by XRD, N2 adsorption-desorption isotherms, ICP-OES, DRIFTS, SEM, TEM and TG techniques before and/or after reaction tests in order to explain the relationship between catalytic activity and catalyst properties. Unlike the other two catalysts (5Ni@10Zr ̶ B and 5Ni@10Zr ̶ S), the formation of hexagonal platelet and short mesochannels was observed in the Zr-SBA-15 supported Ni (5Ni@10Zr ̶ A) catalyst synthesized in the presence of HCl. It was determined that Zr (4.5% by weight) incorporated into the structure of 5Ni@10Zr ̶ A catalyst improved the catalytic activity (85% CH4 and 88% CO2 conversions) and significantly reduced carbon formation. In addition, the highest H2/CO ratio and H2 yield were obtained with 5Ni@10Zr ̶ A catalyst as 0.79 and 1.37, respectively. [ABSTRACT FROM AUTHOR]

Anaerobic co-digestion performance and stabilized sludge quality were investigated with fruit and vegetable wastes in semi-continuous lab-scale reactors for primary (PS), secondary (SS) and mixed sludge (MS) fractions at organic loading rates (OLRs) of 1.65, 0.40 and 1.0 kg VS/m3.day, respectively, at 35°C. Fruit waste (FW), vegetable waste (VW) or fruit+vegetable waste (FVW) fractions were added as co-substrates at different OLR combinations. Optimum OLR values were 0.84, 0.33-0.44 and 1.18 g VS/L.day at %51, 209 and 84% (w:w) respectively for FW, VW and FVW, resulting in increases at 50-75, 250-300 ve 44-66% in daily methane production. Increase in OLRs led to decrease in methane yield and hydrolysis degree in the FW receiving digester whereas a toxic effect took place in VW feeding, especially on methanation with an irreversible pattern in PS co-digestion. VW exhibited a higher biodegradegradability than FW with a higher methane yield while pH was lowered in FW co-digestion. The results showed that co-digestion at low OLRs was beneficial in obtaining higher methane recovery while stabilized sludge worsened in dewatering ability. Stabilized SS gained a suitable level of electrical conductivity and nutrient content for soil application through higher conversion to microbial biomass. [ABSTRACT FROM AUTHOR]

The influence of reaction parameters on the 2Mn/5Na2WO4/SiO2 catalyst for the oxidative coupling of methane was investigated and compared with the results of non-catalytic reaction. The effects of oxidant type (O2 and N2O), CH4/O (1/1-4/1) ratio, GHSV (7500-37500 L kg-1 h-1) and temperature (740-820°C) were evaluated by using one variable at a time procedure. Activity tests showed that high C2 yields could be obtained at low CH4/O ratios and space velocities independent of the oxidant type (O2 or N2O) and reaction medium (catalytic or non-catalytic) within the selected range of parameters. Continuous increase in temperature enhanced the C2 yield especially when N2O was used during the reactions performed without catalyst. The highest C2 yield was 16.4% with the catalyst at CH4/O=1, 7500 L kg-1 h-1 and 780°C using O2. It was found that the highest C2 yield without the catalyst use was 10.1% at CH4/O=1, 7500 L kg-1 h-1 and 820°C using N2O. The catalyst activity towards O2 dissociation is well but poor for N2O decomposition. It was observed that the catalyst did not deactivate despite some sintering and phase changes during 8 hours. [ABSTRACT FROM AUTHOR]