Residence time distribution of wood chips in a semi-industrial multiple hearth furnace using RFID tracers (Open Access)--颗粒学报PARTICUOLOGY

Lacombe, E., Marchand, M., Dupont, C., Maréchal, D., & Melkior, T. (2024). Residence time distribution of wood chips in a semi-industrial multiple hearth furnace using RFID tracers. Particuology, 91, 268-279. https://doi.org/10.1016/j.partic.2024.03.009

Residence time distribution of wood chips in a semi-industrial multiple hearth furnace using RFID tracers (Open Access)

Elie Lacombe^a *, Muriel Marchand^a, Capucine Dupont^b, Denis Maréchal^c, Thierry Melkior^a

a Univ Grenoble Alpes, CEA, LITEN, DTCH, Laboratoire Réacteurs et Procédés, F-38000, Grenoble, France
b IHE Delft, Department of Water Supply Sanitation and Environmental Engineering, Delft, the Netherlands
c John Cockerill, Seraing, Belgium

10.1016/j.partic.2024.03.009

Volume 91, August 2024, Pages 268-279

Received 11 November 2023, Revised 25 March 2024, Accepted 29 March 2024, Available online 11 April 2024, Version of Record 17 April 2024.

E-mail: lacombe.elie@gmail.com

Highlights

• Residence time distribution of wood chips was carried out in a multiple hearth furnace using RFID tracers.

• Lowering interdental length between two successive teeth increases the biomass bed speed.

• Increase of shaft speed and mass flow rate reduces particles' mean residence time.

• Multiple hearth furnace cannot be considered as an ideal plug flow reactor.

Abstract

In continuous biomass torrefaction plants, the products' yields, composition and homogeneity highly depend on the residence time of particles. A characterization of particle residence time distribution (RTD) was therefore carried out in an industrial-scale multiple hearth furnace on poplar wood chips using radio frequency identification tracers. The effects of operating conditions, namely, mass flow rate of biomass, shaft speed of the rabbling system and interdental length on the RTD were studied. The increase of shaft speed and mass flow rate reduces particles’ mean residence time. Lowering the length between two successive teeth also increases the bed speed. Uncontrollable biomass accumulation (also called “bulldozing”) was observed during several tests. This phenomenon is favored by a high mass flow rate of resources, a small interdental length between the teeth and a low shaft speed. RTD measurements were compared to the axial dispersion model. For all tests, the Peclet number is ranging between 20 and 62, indicating that the multiple hearth furnace cannot be modelled as an ideal plug flow reactor.

Graphical abstract

Keywords

Biomass; Multiple hearth furnace; Residence time distribution; RFID

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