Convective drying of mango stone for use as biomass

• Published in: Environmental research 2023-06, Vol.227, p.115742-115742, Article 115742
• Main Authors: Gómez-de la Cruz, Francisco J., Palomar-Torres, Amalia, Pérez-Latorre, Francisco J., Cruz-Peragón, Fernando
• Format: Article
• Language: English
• Subjects: Biomass; Desiccation; Diffusion; Drying rate; Effective diffusivity; Mangifera; Mango stone; Mass transfer; Temperature; Waste recovery
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2023.115742

Mango stone is an interesting biomass by-product with a considerable net calorific value. Mango production has significantly risen in the last few years, meaning that mango waste has increased as well. However, mango stone has a moisture content of about 60% (wet basis) and it is very important to dry the samples for using them in electrical and thermal energy production. In this paper, the main parameters involved in the mass transfer during drying are determined. Drying was carried out in a convective dryer through a set of experiments based on five drying air temperatures (100 °C, 125 °C, 150 °C, 175 °C and 200 °C) and three air velocities (1 m/s, 2 m/s and 3 m/s). Drying times ranged between 2 and 23 h. The drying rate was calculated from the Gaussian model whose values ranged from 1.5·10−6 to 6.3·10−4 s−1. Effective diffusivity was obtained as an overall parameter in the mass diffusion for each test. These values were found between 0.71·10−9 and 13.6·10−9 m2/s. The activation energy was calculated from the Arrhenius law for each test, made at different air velocities. These values were 36.7, 32.2 and 32.1 kJ/mol for 1, 2 and 3 m/s, respectively. This study provides information for future works on design, optimization and numerical simulation models in convective dryers for standard mango stone pieces according to industrial drying conditions. •The main parameters of mass transfer during drying of mango stone were studied.•The design of experiments is based on five air temperatures and three air velocities.•Drying times are very long at low temperatures (100 °C and 125 °C), up to 23 h.•Drying rate and effective diffusivity were calculated considering the drying air temperature and velocity.•There is a barrier effect in the mango stone shell that stunts the water transport.