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

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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References

  1. (2023). REN21. Renewables 2023 Global Status Report. REN21 Secretariat, Paris, France. https://www.ren21.net/gsr-2023/.
  2. (2023). International Energy Agency (IEA). World Energy Outlook 2023. IEA Publications, Paris, France. https://doi.org/10.1787/827374a6-en.
  3. Basu, P. (2018). Biomass gasification, pyrolysis and torrefaction: Practical design and theory (3rd ed.) Practical Design and Theory, pp. 211–262. https://doi.org/10.1016/B978-0-12-812992-0.00007-8.
  4. Bardalai, M. & Mahanta, D. K. (2016). Production of pyrolysis oil from Areca tree using a fixed bed reactor. Journal of Engineering Research, vol. 4, iss. 2, pp. 172–187. https://doi.org/10.1016/S2307-1877(25)00887-9.
  5. Verma, M., Loha, C., Sinha, A. N., & Chatterjee, P. K. (2017). Drying of biomass for utilising in co-firing with coal and its impact on environment – A review. Renewable and Sustainable Energy Reviews, vol. 71, pp. 732–741. https://doi.org/10.1016/j.rser.2016.12.101.
  6. Riaza, J., Álvarez, L., Gil, M. V., Pevida, C., Pis, J. J., & Rubiera, F. (2013). Ignition and NO emissions of coal and biomass blends under different oxy-fuel atmospheres. Energy Procedia, vol. 37, pp. 1405–1412. https://doi.org/10.1016/j.egypro.2013.06.016.
  7. Luk, H. T., Lam, T. Y. G., Oyedun, A. O., Gebreegziabher, T., & Hui, C. W. (2013). Drying of biomass for power generation: A case study on power generation from empty fruit bunch. Energy, vol. 63, pp. 205–215. https://doi.org/10.1016/j.energy.2013.10.056.
  8. Liu, Y., Peng, J., Kansha, Y., Ishizuka, M., Tsutsumi, A., Jia, D., Bi, X. T., Lim, C. J., & Sokhansanj, S. (2014). Novel fluidized bed dryer for biomass drying. Fuel Processing Technology, vol. 122, pp. 170–175. https://doi.org/10.1016/j.fuproc.2014.01.036.
  9. Gautam, K. H. & Devoe, N. N. (2006). Ecological and anthropogenic niches of sal (Shorea robusta Gaertn. f.) forest and prospects for multiple-product forest management – A review. Forestry, vol. 79, iss. 1, pp. 81–101. https://doi.org/10.1093/forestry/cpi063.
  10. Singh, S. & Gupta, A. (2014). Comparative fermentation studies on amylase production by Aspergillus flavus TF-8 using Sal (Shorea robusta) deoiled cake. Industrial Crops and Products, vol. 57, pp. 158–165. https://doi.org/10.1016/j.indcrop.2014.03.035.
  11. Deka, J., Tripathi, O. P., & Khan, M. L. (2012). High dominance of Shorea robusta Gaertn. in alluvial plain Kamrup sal forest of Assam, N.E. India. International Journal of Ecosystem, vol. 2, iss. 4, pp. 67–73. https://doi.org/10.5923/j.ije.20120204.04.
  12. Dimri, R., Majhi, S., Das, K., & Kumar, S. (2026). Distribution, utilization, and ecological services of Sal (Shorea robusta C. F. Gaertn.). Indian Forester, vol. 152, iss. 5, pp. 426–433. https://doi.org/10.36808/if/2026/v152i5/171045.
  13. Pradhan, R. R., Garnaik, P. P., Regmi, B., Dash, B., & Dutta, A. (2017). Pyrolysis kinetics of Sal (Shorea robusta) seeds. Biomass Conversion and Biorefinery, vol. 7, iss. 2, pp. 237–246. https://doi.org/10.1007/s13399-017-0240-3.
  14. Behera, S. K. & Misra, M. K. (2006). Aboveground tree biomass in a recovering tropical Sal (Shorea robusta Gaertn. f.) forest of Eastern Ghats, India. Biomass and Bioenergy, vol. 30, iss. 6, pp. 509–521. https://doi.org/10.1016/j.biombioe.2006.01.003.
  15. Eliaers, P. & De Wilde, J. (2013). Drying of biomass particles: experimental study and comparison of a conventional fluidized bed and a rotating fluidized bed in a static geometry. Drying Technology, vol. 31, iss. 2, pp. 236–245. https://doi.org/10.1080/07373937.2012.726304.
  16. Haque, N. & Somerville, M. (2013). Techno-economic and environmental evaluation of biomass dryer. Procedia Engineering, vol. 56, pp. 650–655. https://doi.org/10.1016/j.proeng.2013.03.173.
  17. Lee, H. W. (2006). Study on the fluidized bed drying characteristics of sawdust as a raw material for wood-pellet fuel. Journal of the Korean Wood Science and Technology, vol. 34, iss. 2, pp. 30–36.
  18. Demirbas, A. (2004). The importance of biomass. Energy Sources, vol. 26, iss. 4, pp. 361–366. https://doi.org/10.1080/0090831049077406.
  19. Castagna, A. & Rein, G. (2025). Surrogate chemical kinetics for drying of biomass and influence of moisture content on the burning behaviour of wood. Proceedings of the Combustion Institute, vol. 41, article 105985. https://doi.org/10.1016/j.proci.2025.105985.
  20. Gandía-Ventura, I., Velázquez-Martí, B., López-Cortés, I., & Guerrero-Luzuriaga, S. (2024). Kinetic models of wood biomass drying in hot airflow systems. Applied Sciences, vol. 14, iss. 15, article 6716. https://doi.org/10.3390/app14156716.
  21. Arabi, M. & Dahmardeh Ghalehno, M. (2026). Thin-layer drying models and artificial neural network for wood fiber drying. BioResources, vol. 21, iss. 1, pp. 654–672. https://doi.org/10.15376/biores.21.1.654-672.
  22. Núñez-Retana, V. D., Carrillo-Parra, A., Escobar Machado, J. A., Moposita-Vasquez, D.-D., & Velázquez-Martí, B. (2025). Predictive models for the convective drying kinetics of Pinus spp. energy wood chips. Applied Sciences, vol. 15, iss. 18, article 10081. https://doi.org/10.3390/app151810081.
  23. Mihindukulasuriya, S. D. F. &. Jayasuriya, H. P. W. (2013). Mathematical modelling of drying characteristics of chilli in hot air oven and fluidized bed dryers. Agricultural Engineering International: CIGR Journal, vol. 15, iss. 1, pp. 154–166.
  24. Safeena, A. & Patil, S. (2013). Effect of hot air oven and microwave oven drying on production of quality dry flowers of Dutch roses. Journal of Agricultural Science, vol. 5, no. 4, pp. 179–189. https://doi.org/10.5539/jas.v5n4p179.
  25. Upadhyaya, A., Gupta, B., Garg, S., Singh, M. B., & Pandey, M. (2012). Mathematical modelling of hot air drying of spinach leaves in universal hot air oven. International Journal of Advanced Research in Computer Engineering & Technology, vol. 1, iss. 4, pp. 153–157.
  26. Faisal, S., Tabassum, R., & Kumar, V. (2013). Performance evaluation and process optimisation of potato drying using hot air oven. Journal of Food Processing Technology, vol. 4, iss. 10, article 273. https://doi.org/10.4172/2157-7110.1000273.
  27. Chen, D., Zheng, Y., & Zhu, X. (2012). Determination of effective moisture diffusivity and drying kinetics for poplar sawdust by thermogravimetric analysis under isothermal condition. Bioresource Technology, vol. 107, pp. 451–455. https://doi.org/10.1016/j.biortech.2011.12.032.
  28. Sridhar, D. & Madhu, G. M. (2015). Drying kinetics and mathematical modelling of Casuarina equisetifolia wood chips at various temperatures. Periodica Polytechnica Chemical Engineering, vol. 59, no. 4, pp. 288–295. https://doi.org/10.3311/PPch.7855.
  29. Kuznetsov, G. V., Syrodoy, S. V., Nigay, N. A., Maksimov, V. I., & Gutareva, N. Y. (2021). Features of heat and mass transfer during drying of large-thickness wood biomass layers. Renewable Energy, vol. 169, pp. 498–511. https://doi.org/10.1016/j.renene.2020.12.137.
  30. Núñez-Retana, V. D., Carrillo-Parra, A., Moposita-Vasquez, D.-D., & Velázquez-Martí, B. (2026). Analysis of convective drying in particles of pine wood chips for bioenergy. Biomass Conversion and Biorefinery, vol. 16, iss. 3, article 96. https://doi.org/10.1007/s13399-025-06957-z.
  31. Loha, C., Das, R., Choudhury, B., Chatterjee, P. K. (2012). Evaluation of air drying characteristics of sliced ginger (Zingiber officinale) in a forced convective cabinet dryer and thermal conductivity measurement. Journal of Food Processing Technology, vol. 6, iss. 3, article 160. https://doi.org/10.4172/2157-7110.1000160.
  32. Perea-Flores, M. J., Garibay-Febles, V., Chanona-Pérez, J. J., Calderón-Domínguez, G., Méndez-Méndez, J. V., Palacios-González, E., & Gutiérrez-López, G. F. (2012). Mathematical modelling of castor oil seeds (Ricinus communis) drying kinetics in fluidized bed at high temperatures. Industrial Crops and Products, vol. 38, pp. 64–71. https://doi.org/10.1016/j.indcrop.2012.01.008.
  33. Phanphanich, M. & Mani, S. (2010). Drying kinetics of pine forest residues. BioResources, vol. 5, iss. 1, pp. 108–121. https://doi.org/10.15376/biores.5.1.108-120.
  34. Jan, K., Riar, C. S., & Saxena, D. C. (2014). Mathematical modelling of thin layer drying kinetics of biodegradable pellets. Journal of Food Processing Technology, vol. 5, iss. 9, article 370. https://doi.org/10.4172/2157-7110.1000370.
  35. Borah, A., Hazarika, K., & Khayer, S. M. (2015). Drying kinetics of whole and sliced turmeric rhizomes (Curcuma longa L.) in a solar conduction dryer. Information Processing in Agriculture, vol. 2, iss. 2, pp. 85–92. https://doi.org/10.1016/j.inpa.2015.06.002.
  36. Taheri-Garavand, A., Rafiee, S., & Keyhani, A. (2011). Effective moisture diffusivity and activation energy of tomato in thin layer dryer during hot air drying. International Transaction Journal of Engineering, Management & Applied Sciences and Technologies, vol. 2, no. 2, pp. 239–248.
  37. Chen, D., Liu, X., & Zhu, X. (2013). A one-step non-isothermal method for the determination of effective moisture diffusivity in powdered biomass. Biomass and Bioenergy, vol. 50, pp. 81–86. https://doi.org/10.1016/j.biombioe.2013.01.023.
  38. Cai, J. & Chen, S. (2008). Determination of drying kinetics for biomass by thermogravimetric analysis under non-isothermal condition. Drying Technology, vol. 26, iss. 12, pp. 1464–1468. https://doi.org/10.1080/07373930802412116.
  39. Gómez-de la Cruz, F. J., Cruz-Peragón, F., Casanova-Peláez, P. J., & Palomar-Carnicero, J. M. (2015). A vital stage in the large-scale production of biofuels from spent coffee grounds: The drying kinetics. Fuel Processing Technology, vol. 130, pp. 188–196. https://doi.org/10.1016/j.fuproc.2014.10.012.
  40. Valente, C., Spinelli, R., Hillring, B. G., & Solberg, B. (2014). Mountain forest wood fuel supply chains: comparative studies between Norway and Italy. Biomass and Bioenergy, vol. 71, pp. 370–380. https://doi.org/10.1016/j.biombioe.2014.09.018.

 

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