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Thermochemical biofuels can be produced locally, contributing to the maintenance of the employment and population in rural areas. Agricultural and forestry residues –almond, plum and holm-oak pruning-, and energy crops biomass –poplar and paulownia- were compared to standards for pellets and woodchips quality. All samples analyzed can be grouped according to Spanish standards for non-industrial solid biofuels –UNE 14961-, except almond woodchips that have a higher ash content than 3%., Proceedings of the 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, pp. 679-681

Sweet sorghum is considered an energy crop with lower water requirements to growth and it is a good substrate to anaerobic co-digestion with microalgae biomass, together they make an optimal nutrient balance. A semi­continuous regime in anaerobic co-digestion has been investigated for different OLR. Previously, batch experiments were evaluated for substrates in mono-digestion. The higher methane yield of the co-digestion was 239 L CH4 kg -1 -1-1 VSfeed and it corresponded to OLR of 1 g VS Ld. VFA/Alkalinity ratio, VFA concentrations and N-NH4 concentrations for experiments were below of the suggested limits for a stable anaerobic co-digestion process., Proceedings of the 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, pp. 883-887

Anaerobic co-digestion of autochthonous microalgae and Scenedesmus sp. with pig manure was investigated under batch and semi-continuous conditions. Low volatile solid (VS) concentrations (1-3%) in batch experiments (microalgae methane potential) yielded higher methane productions than high VS concentrations (5-10%). Semi-continuous anaerobic digestion was inhibited with low OLR (2 kg VS m-3 d-1) when high volatile solid concentration was used, apparently because of elevated ammonia concentration in microalgae biomass and pig manure mixture in the reactor. The low C/N ratio of microalgae biomass, values about 6, suggests the possibility of using other substrates with higher C/N, as can be energy crops and agro-industrial wastes, enhancing process stability with higher organic load rates., Proceedings of the 22nd European Biomass Conference and Exhibition, 23-26 June 2014, Hamburg, Germany, pp. 502-505

In this study, transesterification of rapeseed oil using subcritical methanol and potassium hydroxide as catalyst was studied. The variables affecting the methyl ester yield during the transesterification reaction, such as the catalyst content, reaction temperature, reaction time and the molar ratio of alcohol to oil, were investigated. The results are compared to the obtained using co­solvents. The evolution of the process was followed by gas chromatography, determining the concentration of the methyl esters. The biodiesel was characterized by its density, viscosity, saponification value, iodine value, acidity index and water content, according to ISO norms. High methyl ester yield and fast reaction rate could be obtained even if the reaction pressure was relatively low, which is quite favourable to the production of biodiesel in industry., Proceedings of the 18th European Biomass Conference and Exhibition, 3-7 May 2010, Lyon, France, pp. 1779-1784

This work aimed to study the thermogravimetric degradation of kenaf (Hibiscus cannabinus L) under the effect of several variables. For this purpose, pyrolysis processes, with Ar as inert gas, were accomplished varying the following experimental conditions: particle size (0.14-2 mm), Ar flow rate (25-200 cm3 min-1), sample initial mass (5-21 mg) and heating rate (5-60 K min-1 up to a final temperature of 700ºC). From the results obtained the effect of these variables on the thermal behavior of biomass was discussed and related to the kenaf lignocellulosic composition., Proceedings of the 18th European Biomass Conference and Exhibition, 3-7 May 2010, Lyon, France, pp. 1001-1005

The aim of this work was to optimize the zinc oxide use as a catalyst for the transesterification of rape oil to obtain biodiesel, according to UNE norms. The alkaline and alkaline earth metals­doped ZnO catalysts were prepared by an impregnation method with aqueous solution of metal nitrate. It was done a study of the most influential variables in the catalyst preparation, as type of metals (Li, Na, K, Mg, Ca, Sr, Ba), dose of nitrate load (3­7 mmol/g support), calcination temperature of catalysts (500 and 600ºC) and amount of catalyst (3­9 wt.%). With the best catalysts, it was performed a study of the operation variables in the transesterification system, as agitation rate (300­1100 rpm), and methanol/oil molar ratio (3:1­12:1). The highest catalyst activities in the transesterification was obtained with ZnO loaded with LiNO3 and with Ba(NO3)2. In general, agitation rate, methanol/oil molar ratio, and amount of catalyst exert positive influence in the transesterification process. For both catalysts (Li/ZnO and Ba/ZnO), the optimal conditions were 700 rpm, 9:1 methanol/oil molar ratio, 65ºC, 3 wt.% for Ba and 7 wt.% for Li. Finally, the obtained biodiesel was characterized by means of determination of its properties, according to UNE norms. The final product has very similar properties to a nº. 2 diesel fuel., Proceedings of the 18th European Biomass Conference and Exhibition, 3-7 May 2010, Lyon, France, pp. 1764-1770

The objective of this work was to investigate the thermal decomposition process of kenaf (Hibiscus cannabinus) and to determine their activation energy values associated through a dynamic thermogravimetric analysis by model-free methods. The pyrolysis of kenaf has been carried out by means of thermogravimetric analysis in Ar atmosphere. Four heating rates were used (5-10-20-40 K min-1) up to a final temperature of 700 ºC. The activation energy values were calculated as a function of the extent of conversion during the pyrolysis process by means of Friedman, Kissinger­Akahira-Sunose and Flynn–Wall–Ozawa isoconversional methods. The results showed that there are small differences between the activation energy values obtained from the three methods. Also, a relationship between the activation energy and the conversion reached was found., Proceedings of the 18th European Biomass Conference and Exhibition, 3-7 May 2010, Lyon, France, pp. 997-1000

This work aims to study the thermal behaviour of olive pomace (OP), pyrenean oak (PK) and their blends under pyrolysis using thermogravimetric analysis (TGA). By coupling mass spectrometric analysis (MS) it was possible to monitorize the emissions released during the process. The OP/PK blends were prepared at five different ratios and experiments were carried out under non-isothermal conditions in the temperature range 25-750 ºC using Ar as inert gas. Thus, the following species were analysed: a) aromatic compounds (benzene and toluene), b) sulphur emissions (sulphur dioxide) c) chlorine compounds (dichloromethane) d) 1,4-dioxin and e) carbon dioxide. The results obtained indicated that aromatic compounds are released mainly in the temperature range of 275-455 ºC, where the most significant weight loss are observed in the TG curves. It was found that the maximum of the curves corresponding to these compounds is shifted towards lower values of temperature as the content of OP is increased, which could be related to higher the presence of some inherent minerals in this material (such as potassium). The intensity of sulphur dioxide and chloromethane emissions were related to the composition (S and Cl proportions) of the blends; also the peaks associated to these compounds was shift towards higher temperatures for lower OP contents in both cases., Proceedings of the 18th European Biomass Conference and Exhibition, 3-7 May 2010, Lyon, France, pp. 353-357