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Biomass development appears as an attractive alternative fossil fuels for both energy and fuel production. The study of the pyrolysis of lignocellulosic compounds is important for better understanding of thermochemical biomass conversion processes. These experimental results are extended to materials natural, including lignin and hemicellulose. Experiments have been made to know the nature of the propagation of the reaction of pyrolysis in wood (beech, oak). The second part of this study presents the modeling of pyrolysis process and the temperature profile as well as the pyrolysis reaction of a cylindrical wood. The novelty of this study aims to predict the temperature profile of a wood sample during the pyrolysis process. This state of affairs lies in the difficulty in assessing the proportion of each constituent, but also in the difficulty of obtaining kinetic data relating to the reactions occurring in the pyrolysis process. The thermal balances and the kinetics of reaction of each constituent of the wood have been written and solved by a home-made code, COMMENT code, which allows the representation of the temperature profile within the sample as a function of time. The comparison of the results of this modeling with the experimental temperature profiles shows good agreement. The conversion of reaction was also modeled by the model and compared with that obtained experimentally thanks to the analysis of volatile organic compounds formed during the pyrolysis. Finally, an example of recovery of the pyrolyzed material, namely the production of coals assets, is presented. [ABSTRACT FROM AUTHOR]

Summary: The configuration of an external solar dish improves the performance of stepped slope solar still (SS) in an experimental setting. The use of an external solar dish raises the effects of the water basin, resulting in a higher rate of evaporation. The stepped still was designed, built, and tested in Ismailia, Egypt, using local weather conditions. The proposed SS had a 1 m2 base area and eight steps, a solar dish with a concentration ratio of 80, a cone tank, two centrifugal pumps, four photovoltaic modules totaling 1000 W, a control unit, and solenoid valves. The impact of utilizing the storage material during the phases was investigated. A nozzle was installed at the top of the cone tank. Four mass flow rates of circulated water were examined 250, 350, 450, and 550 mL/min. The control unit receives inputs from the photovoltaic output, photodiodes, and water temperature inside the cone. The control unit outputs the signal for the two solar dish motors, centrifugal pumps, and solenoid valves. First, a standard stepped SS, second, a stepped SS using phase change material (PCM), and finally, a stepped SS using PCM combined with a solar dish were investigated. The conventional stepped SSs with PCM had an optimal mass flow rate of 250 mL/min, whereas the stepped SS integrated with the solar dish had 550 mL/min of mass flow rate (an optimum value). The highest daily freshwater productivity was 7.63, 9.18, 11.23, and 13.9 kg/d for water spraying mass flow rates of 250, 350, 450, and 550 mL/min, respectively, with 0.0161 $/L/m2 of a maximum projected cost, according to data from an integrated stepped SS. [ABSTRACT FROM AUTHOR]