Drying kinetics and energy analysis of carob seeds (Ceratonia siliqua L.) convective solar drying

The drying process is a fundamental operation in the industry that demands much energy and time, this method is used in order to increase the shelf life of the products as well as the mass and volume during the storage and the transportation. The moisture content permits the deterioration of quality through the microorganisms and the enzymatic reactions. This work aims to study the carob seeds (Ceratonia Siliqua L.) solar drying using a convective solar dryer in order to study and understand the drying kinetics and obtain the characteristic drying curve in different temperatures (50, 60, 70 and 80 degrees C) and drying air velocities (0.18 and 0.10 m s(-1)). It was concluded that the increase in the drying temperature reduces the drying time. Six mathematical models were used to appropriately interpret the experimental data; it was found that Verna was the perfect model to represent the drying curves of the carob seeds. The variation of the diffusivity coefficient was found in a range of 1.1968 10(-9)-4.1482 10(-9) m(2) s(-1), an increase in this coefficient is noticed with the increase in the drying temperature. In order to evaluate the activation energy of the studied product, the Arrhenius relation was called and the average activation energy was found to be 41.46 kJ mol(-1). An energy analysis has conducted in order to evaluate the performances of the studied solar dryer. The energy efficiency of the convective dryer was varied in a range of 2.6-4.2%.

Automated summary

The study investigated the solar drying of carob seeds using a convective solar dryer, finding that increasing drying temperature reduces drying time. The Verna mathematical model was found to be the most accurate for representing the drying curves of carob seeds, and the diffusion coefficient increases with drying temperature. An energy efficiency analysis showed that the convective dryer had a range of 2.6-4.2% energy efficiency.