This study reports the initial thermal and thermochemical performance of a novel solarized Auger-type reactor for Pyrolysis (SARP), specifically developed for the valorization of organic solid waste into solar-derived fuels. A key innovation of this system lies in its integration with a high-flux, point-focus solar concentrator that enables controlled delivery of concentrated solar radiation to drive endothermic processes. At the front of the reactor, the thermal evaluation under solar irradiation shows that surface temperatures reached up to approximately 750 °C on the exterior, while the hottest section of the interior briefly reached approximately 700 °C, in the pyrolysis zone. In contrast, the preheating zone inside the reactor exhibits temperatures ranging from 160 °C to 306 °C, indicating a non-uniform thermal profile for the incoming feedstock. The campaign focused on thermochemical pyrolysis, in which pecan walnut tree pruning residue biomass was processed under controlled semicontinuous operation. Batches of 600 g were pyrolyzed, yielding approximately 390 g of biochar and achieving a peak hydrogen concentration of 14.5% vol in the product gases. These findings demonstrate the reactor’s potential for solar-driven waste-to-fuel conversion.

A theoretical and experimental evaluation was conducted on a prototype radiative flux homogenizer (HOFRAC) specifically designed for the Solar Furnace at Instituto de Energías Renovables (HoSIER) of Universidad Nacional Autónoma de México. The development of HOFRAC included three versions (HOFRAC-PRO, HOFRAC-PRI, and HOFRAC-PRIK); each iteration incorporated improvements based on theoretical modeling and experimental results. Evaluations were performed using ray-tracing simulations and experimental tests capturing radiative flux distribution images. The last two versions were used to characterize a densely packed photovoltaic array operated in the solar furnace. Some results of this study show that misaligned mirrors in the furnace were identified as the main problem in achieving a high flux uniformity degree for photovoltaic concentration applications.

This study examines the influence of physical biomass pretreatment on the pyrolysis behavior of woody pruning residues of Carya illinoinensis (pecan tree) processed in a stainless-steel batch reactor heated by concentrated radiative energy. Experiments were conducted with 25.5 g of biomass using a solar simulator equipped with a mirror concentrator, operating at three constant thermal power levels (234, 482, and 725 W). As a pretreatment strategy, the woody residues were deliberately processed without drying, while mechanical size reduction and sieving were applied to obtain a controlled particle size range of 1–4 mm. This approach enabled the isolated assessment of the effects of physical pretreatment, particularly particle size and bulk density, on heat transfer, thermal response, and pyrolysis behavior. The pyrolysis performance of the pretreated woody biomass was systematically compared with that of walnut shell biomass and inert volcanic stones subjected to the same particle size control. Two consecutive experimental cases were implemented: Case A (CA), comprising heating, pyrolysis of fresh biomass, and cooling; and Case B (CB), involving reheating of the resulting biochar under identical operating conditions. An improved analytical methodology integrating temperature–time profiles, their derivatives, and gas composition analysis was employed. The results demonstrated the apparently inert thermal behavior of biochar during reheating and enabled clear temporal identification of the main biomass conversion stages, including drying, active pyrolysis of hemicellulose and cellulose, and passive lignin degradation. However, relative to walnut shell biomass of equivalent volume, the woody pruning residues exhibited attenuated thermal and reaction signals, primarily attributed to their lower bulk density resulting from the selected pretreatment conditions. This reduced bulk density led to less distinct pyrolysis stages and a 4.66% underestimation of the maximum reaction temperature compared with thermogravimetric analysis, highlighting the critical role of physical pretreatment in governing heat transfer efficiency and temperature measurement accuracy during biomass pyrolysis.