Mesopore-modified mordenites as catalysts for catalytic pyrolysis of biomass and cracking of vacuum gasoil processes

[EN] Mesopore-modified mordenite zeolitic materials with different Si/Al ratios have been repared and tested in the biomass pyrolysis and catalytic cracking of vacuum gasoil. Alkaline treatment was carried out to generate mesoporosity. Severity of alkaline treatment was found to be of paramount importance to tune the generated mesoporosity, while it significantly affected the crystallinity of treated mordenites. It was moreover observed that the alkaline treatment selectively extracted Si decreasing the Si/Al ratio of treated samples. Catalytic activity of parent and alkaline treated mordenites was studied in the pyrolysis of biomass. All zeolitic based materials produced less amounts of bio-oil but of better quality (lowering the oxygen content from ∼40% to as much as 21%) as compared to the non-catalytic pyrolysis experiments. On the other hand, it was found that the combination of mesopore formation and high surface area after alkaline treatment of the mordenite with a high Si/Al ratio resulted in the enhancement of its catalytic activity, despite the reduction of its acidity. The increment of the decarboxylation and dehydration reactions, combined with a reduction of carbon deposition on the catalyst, resulted in a remarkable decrease in the oxygen content in the organic fraction and therefore, resulted in a superior quality liquid product. Alkaline treated mordenites were additionally acid treated targeting dealumination and removal of the extra framework debris, thus generating mesopore-modified mordenite samples with stronger acid sites and higher total acidity, as candidate catalysts for catalytic cracking of vacuum gasoil. Desilicated and especially desilicated and dealuminated mordenites exhibited the highest activity and selectivity towards LCO with the best olefinicity in gases and higher bottoms conversion. Therefore, an optimized desilicated dealuminated mordenite additive could be an interesting candidate as a component of the FCC catalyst for a high LCO yield.The financial support of this work by the ACENET COMMON INITIATIVE HECABIO: "HEterogeneous CAtalysis for the Conversion of Solid BIOmass into Renewable Fuels and Chemicals" Project ACE.07.026 is gratefully acknowledged.Stefanidis, S.; Kalogiannis, K.; Iliopoulou, EF.; Lappas, AA.; Martínez Triguero, LJ.; Navarro Ruiz, MT.; Chica, A.... (2013). Mesopore-modified mordenites as catalysts for catalytic pyrolysis of biomass and cracking of vacuum gasoil processes. Green Chemistry. 15(6):1647-1658. doi:10.1039/c3gc40161hS1647165815

Exploring the Biochemical Methane Potential of Wholesale Market Waste from Jordan and Tunisia for a Future Scale-Up of Anaerobic Digestion in Amman and Sfax

3 Figuras.-- 2 TablasLocal open markets, trading fruits and vegetables, are widespread in Mediterranean countries, such as Tunisia and Jordan, producing large amounts of organic waste. Applying an anaerobic digestion process on this substrate makes it crucial to evaluate the waste mixture composition and seasonal variability properly. In this study, after defining an average composition of the fruit and vegetable waste (FVW) mixture produced in Sfax (Tunisia) and Amman (Jordan) in three seasonal intervals (autumn–winter, spring, and summer), the biochemical methane potential (BMP) of an artificially created FVW mixture was individually determined by three European institutions located in Spain, Italy, and Greece. The average BMP from all three seasons and laboratories was 286 ± 52 NmL CH4 g CODadded−1, close to the theoretical maximum yield of 350 NmL CH4 g CODadded−1, indicating a high biodegradability of the waste. Τhe biochemical methane yields of the spring mixtures were not statistically different across the three labs. The most significant differences among the BMP results were obtained for the autumn/winter and the summer mixtures used in Spain, likely due to the variety or ripeness of fruits and vegetables collected in the local markets. In the other two labs in Italy and Greece, no statistical difference was observed for the BMPs of the three season mixtures within the same lab. Therefore, not a critical difference in the biodegradability of such FVW is expected along the different seasons, indicating that the operation of a full-scale digester over a whole year would constantly benefit from the supplementation of a high biochemical methane potential feedstock. Graphical Abstract: [Figure not available: see fulltext.]This work was funded by the project entitled “Employing circular economy approach for OFMSW management within the Mediterranean countries – CEOMED” number A_B.4.2_0058, funded under the ENI CBC MED 2014–2020 programmePeer reviewe

Behaviour of EHD films subjested to lateral oscillations

In many machine elements working in the elastohydrodynamic lubrication regime the components are subjected to low amplitude oscillatory motions, which disturb the conditions for optimum formation of the lubricant film. Most of these applications involve combined vibrations in both vertical and longitudinal directions. For example, in gears and rolling element bearings vertical vibrations may be caused by changes in load, speed or geometry at the contact point, while the longitudinal vibration is often a direct result of the torsional vibrations of the shaft. Vibrations also transmit to these machine elements from other parts of the assembly or from the surrounding environment. Vibrations are usually harmful because they reduce the accuracy of motion and may impede the formation of a lubricant film, thus affecting the durability of machine components.The aim of this is study is to investigate the behaviour of EHD films during lateral oscillatory motion using the optical interferometry technique

Noteworthy new floristic records from Greece [Interesantni novi floristički podaci iz Grčke]

This contribution to the Greek flora includes distribution extensions and taxonomic notes for some noteworthy plant taxa. New records for certain phytogeographical regions of Greece are presented for: Arum cylindraceum, Convolvulus pentapetaloides. Cruciata taurica, Galanthus reginae-olgae subsp. vernalis, Ilex aquifolium, Linum decumbens, Lythrum thymifolia, Sedum praesidis, Silene congesta and Trifolium diffusum. Allium karistanum, Helichrysum amorginum, Limonium antipaxorum and L. cephalonicum have been recorded for the first time on some islands. New populations of Allium maniaticum and A. ritsii, previously known only from their loci classici, were discovered in the Peloponnese. Valeriana alliariifolia, Silene auriculata subsp. auriculata and Symphytum creticum were rediscovered in central Evvia, confirming long-lost historical records from previous centuries. The presence of V. alliariifolia in Greece and Europe is confirmed for the first time since the 19th century. © 2021. Institute of Botany and Botanical Garden Jevremovac, Belgrad

Effects of cadmium and 17\u3b2-estradiol on Mytilus galloprovincialis redox status. Prooxidant\u2013antioxidant balance (PAB) as a novel approach in biomonitoring of marine environments

Cadmium and 17\u3b2-estradiol are rapidly accumulated in mussel tissues, making mussels excellent pollution sentinel organisms. The aim of the present study was to compare the oxidative responses of the mussels after 1, 3 and 7 days of exposure to cadmium with those to 17\u3b2-estradiol and subsequently, to suggest a multi-parametric approach for biomonitoring studies. Our results showed that environmentally relevant concentrations of either cadmium or 17\u3b2-estradiol for 1, 3 and 7 days induced oxidative stress in hemocytes of exposed mussels. The latter was determined by significantly increased ROS levels and apoptosis, by suppression of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione-S-transferase (GST) expression levels and subsequent increased prooxidant levels, as measured by prooxidant-antioxidant balance (PAB) assay. To our knowledge this is the first time that prooxidant-antioxidant balance is evaluated in invertebrates as an index of oxidative stress. The simultaneous use of the parameters of prooxidant-antioxidant balance and antioxidant enzymes expression patterns, in combination with ROS production levels and apoptosis, in mussel hemocytes is suggested as an approach that may help to better evaluate the impact of environmental pollution on marine organisms and thereupon ecosystems

Second-generation biofuels by co-processing catalytic pyrolysis oil in FCC units

INGENIERIE+NTE:GFO:YSC:CMIInternational audiencePrevious research showed that hydrodeoxygenated (HDO) pyrolysis-oils could successfully be co-processed with vacuum gasoil (VGO) in a labscale fluid catalytic cracking (FCC) unit to bio-fuels. Typically the hydrodeoxygenation step takes place at similar to 300 degrees C under 200-300 bar of hydrogen. Eliminating or replacing this step by a less energy demanding upgrading step would largely benefit the FCC co-processing of pyrolysis oils to bio-fuels. In this paper a bio-oil that has been produced by catalytic pyrolysis (catalytic pyrolysis oil or CPO) is used directly, without further upgrading, in catalytic cracking co-processing mode with VGO. The results are compared to the co-processing of upgraded (via HDO) thermal pyrolysis oil. Though small but significant differences in the product distribution and quality have been observed between the co-processing of either HDO or CPO, they could be corrected by further catalyst development (pyrolysis and/or FCC), which would eliminate the need for an up-stream hydrodeoxygenation step. Moreover, the organic yield of the catalytic pyrolysis route is estimated at approximately 30 wt.% compared to an overall yield for the thermal pyrolysis followed by a hydrodeoxygenation step of 24 wt.%. (C) 2013 Elsevier B.V. All rights reserved