Comparative pyrolysis studies of lignocellulosic biomasses: Online gas quantification, kinetics triplets, and thermodynamic parameters of the process.

This study focused on the analysis of the pyrolytic behavior of four lignocellulosic biomasses: avocado stone (AS), Agave salmiana bagasse (AB), cocoa shell (CS), and α-cellulose (CEL). According to the triplet kinetics analysis, the order of pyrolytic decomposition was AS < AB < CEL < CS. The AS was dominated by a second-order reaction, while AB followed a 2D diffusion-Valensi model. On the other hand, the pyrolysis of CS starts with an nth-order reaction and ends random nucleation model, and CEL was dominated by one-dimensional diffusion and first-order reaction. Thermodynamic studies reveal that the difference between the activation energy versus enthalpy change was<6.5 kJ/mol for all biomasses, thus showing the ease of pyrolysis reaction of these biomasses. Furthermore, the AS and AB showed that the reactions are close to thermodynamic equilibrium and stability, whereas CS and CEL indicated high reactivity.

Biomolecules from olive pruning waste in Sierra Mágina - Engaging the energy transition by multi-actor and multidisciplinary analyses.

The price volatility of fossil resources, the uncertainty of their long-term availability and the environmental, climatic and societal problems posed by their operation lead to the need of an energy transition enabling the development and utilization of other alternative and sustainable resources. Acknowledging that indirect land-use change can increase greenhouse gas emission, the European Union (EU) has reshaped its biofuel policy. It has set criteria for sustainability to ensure that the use of biofuels guarantees real carbon savings and protects biodiversity. From a sustainability perspective, biofuels and bioliquids offer indeed both advantages (e.g., more secure energy supply, emission reductions, reduced air pollution and production of high added-value molecules) as well as risks (monocultures, reduced biodiversity and even higher emissions through land use change). Approaching economic, environmental and social sustainability at the local level and in an integrated way should help to maximize benefits and minimize risks. This approach has been adopted and is described in the present work that combines chemical, biological, social and territorial studies on the management of pruning waste residues from olive trees in the Sierra Mágina in Spain. The biological and social analyses helped to orientate the research towards an attractive chemical process based on extraction and pyrolysis, in which high added value molecules are recovered and in which the residual biochar may be used as pathogen-free fertilizer. In this region where farmers face declining economic margins, the new intended method may both solve greenhouse gas emission problems and provide farmers with additional revenues and convenient fertilizers. Further research with a larger partnership will consolidate the results and tackle issues such as the logistics.