The present study investigates the air-steam gasification of ten commercial and alternative lignocellulosic biomass fuels (pine sawdust, chestnut sawdust, torrefied pine sawdust, torrefied chestnut sawdust, almond shells, cocoa shells, grape pomace, olive stones, pine kernel shells and pine cone leafs) in order to evaluate the product gas composition and the process performance in a bubbling fluidized bed gasifier with focus on the different biomass properties. Accordingly, an effort to correlate the biomass characteristics with the gasification results has been done. Pine kernel shell (PKS) was used to test the effect of the gasification temperature (700, 800 and 900 ºC), steam to air ratio in the gasifying agent (S/A=10/90, 25/75, 50/50 and 70/30) and stoichiometric ratio (SR=0.13 and 0.25) on the product gas composition, combustible gas (H2+CO+CH4) production, H2/CO ratio, heating value, energy yield and cold gas efficiency of the obtained gas. Results showed that higher temperature and S/A ratio favored H2 production and gasification performance. A higher value of SR slightly affected the gas composition, but led to a higher process efficiency as a consequence of a higher biomass conversion into gaseous combustible products. All the biomass samples of different origin and characteristics were then gasified at the best experimental conditions found (900 ºC, S/A=70/30, SR=0.25). Gasification of all the biomasses was feasible and H2 and combustible gas concentrations of 30-39 vol% and 59-78 vol% (inert gas-free basis), respectively, were obtained for the biomasses studied, with energy yields of 8-18 MJ/kgbiomass. Torrefied biomass showed similar combustible gas production than the corresponding raw biomass under the conditions studied, but it gave slightly higher H2 production and efficiency results. Possible correlations of the gasification performance

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Biomass shows characteristics that makes it a promising feedstock for complementing traditional fossil fuels as main energy source. It is somewhat limited by its generally poor physical properties, but these can be enhanced by densification processes like torrefaction and pelletization. The aim of the present work is to evaluate the influence of different solid biomass additives (almond shell, cocoa shell, grape pomace, Miscanthus, olive pomace and olive stone), and parameters such as temperature, moisture content and glycerol addition upon pine sawdust, PIN, and its torrefied counterpart, PINT, pelletization performance, paying special attention to their abrasion index, higher heating value and energy density. It was observed that the addition of small quantities of lignin-rich solid additives, like grape pomace, enhances the natural binding properties of both PIN and PINT during pelletization using a bench-scale device. It was also found that a 13% overall moisture content and a glycerol addition of between 10-20% improve the pelletization properties of PIN and PINT, respectively, and increase their energy density when compared to the raw samples.

Multivariate analysis was used to study the influence of the biomass characteristics on the gasification process. Ten lignocellulosic biomass samples (almond shells-AS-, chestnut sawdust-CHE-, torrefied chestnut sawdust-CHET-, cocoa shells-CS-, grape pomace-GP-, olive stones-OS-, pine cone leafs-PCL-, pine sawdust-PIN-, torrefied pine sawdust-PINT-, and pine kernel shells-PKS-) were gasified in a bubbling fluidized bed gasifier under an air-steam atmosphere. Statistical analysis was applied to the variables that described the results of the gasification process, i.e., gas concentration, gas production (moles), calorific value of the product gas, energy density, and cold gas efficiency, together with the main biomass properties, such as those derived from the elemental and proximate analyses, the higher heating value (HHV), the particle density, and the elemental composition of the ashes. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied to the data of biomass properties and gasification parameters in order to elucidate which feedstock features had a more determinant influence on the gasification process. Both HCA and PCA revealed a clear separation of the biomass samples into two main groups on the basis of the gasification results. The results indicated that PKS, PCL, PINT, OS and PIN biomasses were characterized by high production of combustible gases, such as CO and CH4, high conversion and cold gas efficiency during gasification. This indicated that the most important biomass properties for promoting the gas production, calorific value of the product gas, gasification conversion and energy efficiency were the C and H contents and the HHV of the biomass. However, biomasses CS and GP were mainly characterized by high H2 concentration and H2/CO molar ratio in the gas product, which was mainly related to the higher H/O ratio and K2O ash content of the biomass. The H2 concentration in the product gas was negatively

Investigation into clean energies has been focused on finding an alternative to fossil fuels in order to reduce global warming while at the same time satisfying the world's energy needs. Biomass gasification is seen as a promising thermochemical conversion technology as it allows useful gaseous products to be obtained from low-energy-density solid fuels. Air-steam mixtures are the most commonly used gasification agents. The gasification performances of several biomass samples and their mixtures were compared. One softwood (pine) and one hardwood (chestnut), their torrefied counterparts, and other Spanish-based biomass wastes such as almond shell, olive stone, grape and olive pomaces or cocoa shell were tested, and their behaviors at several different stoichiometric ratios (SR) and steam/air ratios (S/A) were compared. The optimum SR was found to be in the 0.2-0.3 range for S/A = 75/25. At these conditions a syngas stream with 35% of H 2 + CO and a gas yield of 2 L gas/g fuel were obtained, which represents a cold-gas efficiency of almost 50%. The torrefaction process does not significantly affect the quality of the product syngas. Some of the obtained chars were analyzed to assess their use as precursors for catalysts, combustion fuel or for agricultural purposes such as soil amendment.