Drying Kinetics of Sal Wood (Shorea Robusta): Moisture Diffusivity, Activation Energy, and Biomass Energy Implications

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DOI
Journal Journal of Mechanical Engineering – Problemy Mashynobuduvannia
Publisher Anatolii Pidhornyi Institute of Power Machines and Systems
of National Academy of Science of Ukraine
ISSN  2709-2984 (Print), 2709-2992 (Online)
Issue Vol. 29, no. 3, 2026 (September)
Pages 43-55
Cited by J. of Mech. Eng., 2026, vol. 29, no. 3, pp. 43-55

 

Authors

Munna Verma, Bhagwant University (Ajmer-305004, Rajasthan, India), ORCID: 0000-0003-2146-3234

Ravi Kant Ranjan, Government Polytechnic Sahjanwa (Gorakhpur – 273209, Uttar Pradesh, India), e-mail: ravi.me11@nitp.ac.in, ORCID: 0000-0002-4023-689X

 

Abstract

This paper investigates the isothermal drying kinetics and effective moisture diffusivity of cylindrical Shorea robusta (Sal) wood particles dried in a hot air oven at 75 °C, 90 °C, and 105 °C. Sal wood, one of the most ecologically and commercially significant hardwood species of the Indian subcontinent, holds considerable promise as a biomass fuel feedstock, yet its drying characteristics have not been systematically characterized. Five established thin-layer drying models; Lewis, Page, Modified Page, Wang & Singh, and Henderson & Pabis, were fitted to the experimental moisture ratio (MR) data using MATLAB curve fitting. The Page model provided the best statistical fit, yielding coefficients of determination (R²) of 0.9971, 0.9988, and 0.9983; sum of squares of error (SSE) values of 0.003618, 0.001854, and 0.003047; and root mean square error (RMSE) values of 0.01608, 0.01151, and 0.01425 at 75°C, 90°C, and 105°C, respectively. Effective moisture diffusivity, calculated via the analytical solution of Fick’s second law for cylindrical geometry, increased from 7.92×10⁻8 to 26.0×10⁻8 m²/s over the experimental temperature range. Activation energy, estimated using an Arrhenius-type equation, was found to be 4.42×10⁴  J/mol, consistent with values reported for analogous lignocellulosic biomasses. The findings provide fundamental kinetic data for rational dryer design and optimisation of biomass pre-treatment systems.

 

Keywords: activation energy, drying kinetics, effective moisture diffusivity, hot air oven, thin-layer drying.

 

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Received 18 July 2026
Accepted 26 August 2026
Published 30 September 2026