Valorization of organic municipal solid waste to enhanced solid biofuel: torrefaction kinetics, torrefied solid fuel performance, and fuel properties

ABSTRACT

The kinetics of the torrefaction process have been studied in various reactors. However, no study reported the torrefaction kinetics of organic municipal solid waste (OMSW) in a helical screw rotation-induced (HSRI) fluidized bed reactor. This study produced torrefied solid fuel, and the kinetic parameters of the OMSW torrefaction process were determined. The results showed that increasing temperature and residence time from 200 to 300°C and 0 to 40 minutes increased mass loss, calorific value, ash content, fixed carbon, energy density, and carbon content. Conversely, mass yield, volatile matter, energy yields, oxygen-to-carbon, and hydrogen-to-carbon ratios decreased. The calorific value experienced notable growth, varying from 17.80 to 26.18 MJ/kg, with increased residence time and temperature. The one-step kinetic model using a first-order reaction accurately predicts reaction data for long residence times with a maximum error of 2.42% at 300°C and 10 minutes and is useful for designing and scaling up the HSRI fluidized bed reactor within the temperature and mass loss ranges of 220–300°C and 2.61–47.38%. The OMSW torrefaction frequency factor and activation energy were 0.2036 s⁻¹ and 24.46 kJ/mol, respectively. The findings of this study showed that residence time has less effect on the torrefaction process than temperature.

GRAPHICAL ABSTRACT

KEYWORDS:

• Torrefaction
• helical screw rotation-induced fluidized bed reactor
• calorific value
• kinetic parameters
• torrefied solid fuel
• one-step kinetic model

Highlights

• Enhanced torrefied solid fuel (TSF) was produced successfully.

• HSRI torrefaction produced high-energy-dense solid fuel (up to 26.18 MJ/kg).

• Temperature has more influence on torrefied solid fuel than time.

• TSF is characterized by decarbonization<dehydrogenation<deoxygenation.

Acknowledgements

This work was supported by the University of Malaya (Grant number: IIRG003A-2020FNW) and the Petroleum Technology Development Fund (PTDF).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2023.2283616.

Additional information

Funding

This work was supported by the Petroleum Technology Development Fund; Universiti Malaya [IIRG003A-2020FNW].

Notes on contributors

Kabir Abogunde Abdulyekeen

Kabir Abogunde Abdulyekeen conceptualization; data curation; methodology; investigation; formal analysis; validation; visualization; writing—original draft; visualization; writing—reviewing and editing.

Wan Mohd Ashri Wan Daud

Wan Mohd Ashri Wan Daud conceptualization; supervision; funding acquisition; writing—reviewing and editing.

Muhamad Fazly Abdul Patah

Muhamad Fazly Abdul Patah supervision; resources; funding acquisition.