Exergy and energy analyses of two biodiesel production processes that integrate solar energy as the main energy source were developed to determine the process with the higher efficiency from an energy and exergy approach. The biodiesel production processes were simulated in ASPEN PLUS^®, and the solar energy supply was studied in TRNSYS^®, using EXCEL^® simultaneously for the exergetic analysis. The solar thermal energy collection system can supply 81% of the energy required by the alkali process in the Flash separation equipment. For the supercritical process, solar thermal energy can supply 74.5% of the energy in the preheating and separation stages. The energy efficiency of the supercritical process is higher; nevertheless, the exergetic efficiency of the alkaline process is higher than the supercritical one. Solar collection systems contribute from 85% to 93% of the exergy destroyed by the global process for both cases. The alkaline biodiesel production process has the highest advantages when using solar energy as the main source of energy, compared to a process in supercritical conditions that presents greater irreversibilities and requires more infrastructure to collect the solar resource. However, using solar energy as the foremost energy source offers an alternative to fossil fuels, and it provides an environmental benefit concurrently with the use of biodiesel.

The growth of industrialization in Mexico has caused an increase in the demand for materials to satisfy the consumption of goods and services of a growing population. Given this scenario, there is a rise of the residual generation with affectations on the ecosystem and population health. Hence, the objective of this research was to design a network for waste vegetable oil collection based on vehicle routing problem with simultaneous pickup and delivery, starting from a distribution centre to 49 restaurants, as the generation sources of waste vegetable oil. The Vehicle Routing Problem Simultaneous Pickup and Delivery with Time Windows was the variant used as a vehicle routing method to solve the problem. The free software VPRPD was the tool used to solve the vehicle routing problem with simultaneous pickup and delivery that allowed to specify time restrictions. This software uses the simulated annealing metaheuristics in its syntax. As a result, it was obtained a total of 8 networks, for a vehicle capacity utilization of 70 percent in the 6 t vehicle and 46 percent in the 8 t vehicle.

Bioethanol is a promising alternative to fossil fuels. This study evaluated bioethanol production from orange peel (OP) and brewer’s spent grain (BSG) through acid hydrolysis, followed by fermentation with Saccharomyces cerevisiae. A factorial design was applied to assess the influence of temperature, acid concentration, and time on sugar release. Hydrolysis of OP at 125 °C with 0.5% H₂SO₄ yielded 52.14 g/L of glucose and 15.70 g/L of xylose. For BSG, the best results were obtained with 2.5% H₂SO₄ at 160 °C, producing 27.10 g/L of glucose and 14.22 g/L of xylose. Fermentation at 30 °C achieved 5.25% v/v bioethanol in OP and 1.5% v/v in BSG, representing 41.4 g/L and 11.8 g/L of bioethanol, respectively. The kinetic models showed high predictive accuracy (R² > 0.98). These findings demonstrate the potential of OP and BSG as viable substrates for bioethanol production under mild processing conditions.