Biomass Torrefaction in a Bench-Scale Screw Reactor: Effect of Temperature and Biomass Type

Keywords: Biomass energy, energy efficiency, temperature, torrefaction


The intensive use of fossil fuels contributes significantly to global warming and the growing world energy crisis. Thus, it is necessary to develop alternative energy sources that make the energy matrix more flexible and reduce environmental impacts. An outstanding option is the conversion of residual biomass into energy because it produces a low-emission fuel in terms of CO2. Therefore, this study aimed to improve the physicochemical properties of two residual biomasses (i.e., pine sawdust and spent coffee ground, SCG) through a torrefaction process. Biomass valorization was carried out in a bench-scale screw reactor (2.8 kg/h). The effect of temperature was evaluated between 200 °C and 300 °C, and the torrefied biomasses were characterized by instrumental techniques: calorific value, infrared spectroscopy analysis, thermogravimetric analysis, and scanning electron microscopy. Both biomasses exhibited an increase in calorific value when the process temperature was raised. This behavior is associated with the thermal degradation of the hemicellulose fraction and the increase in fixed carbon. In addition, the infrared analysis showed a decrease in OH and H-O-H signals associated with polar functional groups. These results show the high potential of the valorization of these two biomasses thanks to the decrease in polar groups, which have a great affinity with water, and the obtaining of calorific values close to those of fossil fuels such as lignite or sub-bituminous coal.

Author Biographies

Fredy E. Jaramillo , Universidad del Sinú, Colombia

Universidad del Sinú, Montería Córdoba-Colombia,

Pedro N. Alvarado* , Instituto Tecnológico Metropolitano, Colombia

Instituto Tecnológico Metropolitano, Medellín-Colombia,

Ricardo A. Mazo , Instituto Tecnológico Metropolitano, Colombia

Instituto Tecnológico Metropolitano, Medellín- Colombia,


Consejo Nacional de Política Económica y Social, “Documento CONPES 3934 de 2018. Política de Crecimiento Verde”, Cons. Nac. Política Económica Y Soc. República Colomb. Dep. Nac. Planeación, 2018.ómicos/3934.pdf

Departamento Nacional de Planeación e Instituto Global de Crecimiento Verde, Diagnóstico de Crecimiento Verde: Análisis macroeconómico y evaluación del potencial de crecimiento verde en Colombia, 1st ed., no. May. Bogotá, 2017

Ministerio de Ambiente y Desarrollo Sostenible - MADS, Política nacional de cambio climático, 1st ed. Bogotá, 2016

L. Kumar; A. A. Koukoulas; S. Mani; J. Satyavolu, “Integrating Torrefaction in the Wood Pellet Industry: A Critical Review”, Energy & Fuels, vol. 31, no. 1, pp. 37–54, Jan. 2017.

A. F. Gracía-Muñoz; C. E. Riaño-Luna, “Extracción De Celulosa a Partir De La Borra De Café”, Cenicafé, vol. 50, no. 3, pp. 205–214, 1999.

P. S. Murthy; M. Madhava Naidu, “Sustainable management of coffee industry by-products and value addition—A review”, Resour. Conserv. Recycl., vol. 66, pp. 45–58, Sep. 2012.

B. Janissen; T. Huynh, “Chemical composition and value-adding applications of coffee industry by-products: A review”, Resour. Conserv. Recycl., vol. 128, pp. 110–117, Jan. 2018.

M. Kopczyński; J. A. Lasek; A. Iluk; J. Zuwała, “The co-combustion of hard coal with raw and torrefied biomasses (willow (Salix viminalis), olive oil residue and waste wood from furniture manufacturing)”, Energy, vol. 140, part. 1, pp. 1316–1325, Dec. 2017.

E. G. Eddings; D. McAvoy; R. L. Coates, “Co-firing of pulverized coal with Pinion Pine/Juniper wood in raw, torrefied and pyrolyzed forms”, Fuel Process. Technol., vol. 161, pp. 273–282, Jun. 2017.

M. V. Gil; F. Rubiera, Coal and biomass cofiring: fundamentals and future trends. Elsevier, 2019.

Y.-H. Li; H.-T. Lin; K.-L. Xiao; J. Lasek, “Combustion behavior of coal pellets blended with Miscanthus biochar”, Energy, vol. 163, pp. 180–190, Nov. 2018.

J. F. Pérez; M. R. Pelaez-Samaniego; M. Garcia-Perez, “Torrefaction of Fast-Growing Colombian Wood Species”, Waste Biomass Valorization, vol. 10, no. 6, pp. 1655–1667, Jun. 2019.

S. Ramos-Carmona; J. D. Martínez; J. F. Pérez, “Torrefaction of patula pine under air conditions: A chemical and structural characterization”, Ind. Crops Prod., vol. 118, pp. 302–310, Aug. 2018.

Q.-V. Bach; Ø. Skreiberg, “Upgrading biomass fuels via wet torrefaction: A review and comparison with dry torrefaction”, Renew. Sustain. Energy Rev., vol. 54, pp. 665–677, Feb. 2016,

B. Batidzirai; A. P. R. Mignot; W. B. Schakel; H. M. Junginger; A. P. C. Faaij, “Biomass torrefaction technology: Techno-economic status and future prospects”, Energy, vol. 62, pp. 196–214, Dec. 2013.

S. S. Thanapal; K. Annamalai; R. J. Ansley; D. Ranjan, “Co-firing carbon dioxide-torrefied woody biomass with coal on emission characteristics”, Biomass Convers. Biorefinery, vol. 6, no. 1, pp. 91–104, Mar. 2016.

W.-H. Chen; P.-C. Kuo, “A study on torrefaction of various biomass materials and its impact on lignocellulosic structure simulated by a thermogravimetry”, Energy, vol. 35, no. 6, pp. 2580–2586, Jun. 2010.

Y. Yue; H. Singh; B. Singh; S. Mani, “Torrefaction of sorghum biomass to improve fuel properties”, Bioresour. Technol., vol. 232, pp. 372–379, May 2017.

A. Cardarelli; S. Pinzi; M. Barbanera, “Effect of torrefaction temperature on spent coffee grounds thermal behaviour and kinetics”, Renew. Energy, vol. 185, pp. 704–716, Feb. 2022.

M. Barbanera; I. F. Muguerza, “Effect of the temperature on the spent coffee grounds torrefaction process in a continuous pilot-scale reactor”, Fuel, vol. 262, p. 116493, Feb. 2020.

F. E. Jaramillo; P. N. Alvarado, “Thermogravimetric evaluation of torrefaction parameters on thermal properties of a colombian woody biomass”, Chem. Eng. Trans., vol. 80, pp. 133–138, Apr. 2020.

E. A. Gómez; L. A. Ríos; J. D. Peña, “Madera, un Potencial Material Lignocelulósico para la Producción de Biocombustibles en Colombia”, Inf. Tecnológica, vol. 23, no. 6, pp. 73–86, Jul. 2012.

H. Escalante Hernández; J. Orduz Prada; H. J. Zapata Lesmes; M. C. Cardona Ruiz; M. Duarte Ortega, “Atlas del Potencial Energético de la Biomasa Residual en Colombia,” Bucaramanga, Colombia, 2011.

A. A. Arrieta et al., “Consultoría técnica para el fortalecimiento y mejora de la base de datos de factores de emisión de los combustibles colombianos- FECOC”, Cali-Medellin, 2016.

ASTM International, “Standard Practice for Collection of a Gross Sample of Coal”, vol. ASTM D2234, 2020.

ASTM International, “Standard Test Method for Compositional Analysis by Thermogravimetry”, no. C, pp. 9–13, 2012, doi:

ASTM International, “Standard Test Method for Gross Calorific Value of Coal and Coke”, vol. ASTM D5865, 2019.

R. W. Nachenius; T. A. van dee Wardt; F. Ronsse; W. Prins, “Torrefaction of pine in a bench-scale screw conveyor reactor”, Biomass Bioenergy, vol. 79, pp. 96–104, Aug. 2015.

W.-H. Chen; J. Peng; X. T. Bi, “A state-of-the-art review of biomass torrefaction, densification and applications”, Renew. Sustain. Energy Rev., vol. 44, pp. 847–866, Apr. 2015.

J. S. Tumuluru; S. Sokhansanj; J. R. Hess; C. T. Wright; R. D. Boardman, “A review on biomass torrefaction process and product properties for energy applications”, Ind. Biotechnol., vol. 7, no. 5, pp. 384–401, Oct. 2011.

B. Acharya; I. Sule; A. Dutta, “A review on advances of torrefaction technologies for biomass processing”, Biomass Convers. Biorefinery, vol. 2, no. 4, pp. 349–369, Dec. 2012.

K. T. Lee et al., “Spent coffee grounds biochar from torrefaction as a potential adsorbent for spilled diesel oil recovery and as an alternative fuel”, Energy, vol. 239, part. E, p. 122467, Jan. 2022.

D. A. Granados; H. I. Velásquez; F. Chejne, “Energetic and exergetic evaluation of residual biomass in a torrefaction process”, Energy, vol. 74, pp. 181–189, Sep. 2014.

W.-H. Chen; K.-M. Lu; S.-H. Liu; C.-M. Tsai; W.-J. Lee; T.-C. Lin, “Biomass torrefaction characteristics in inert and oxidative atmospheres at various superficial velocities”, Bioresour. Technol., vol. 146, pp. 152–160, Oct. 2013.

W.-H. Chen; P.-C. Kuo, “Torrefaction and co-torrefaction characterization of hemicellulose, cellulose and lignin as well as torrefaction of some basic constituents in biomass”, Energy, vol. 36, no. 2, pp. 803–811, Feb. 2011.

L. A. Rodríguez Romero; C. Gutiérrez- Antonio; J. F. García Trejo; A. A. Feregrino-pérez, “Estudio comparativo de modelos matemáticos para predecir el poder calorífico de residuos agrícolas mexicanos”, TecnoLógicas, vol. 25, no. 53, e2142, Feb. 2022.

N. Rodríguez Valencia; D. A. Zambrano Franco, “Los subproductos del café: fuente de energía renovable”, Av. Técnicos Cenicafé, no. 393, p. 8, Mar. 2010.

R. H. H. Ibrahim; L. I. Darvell; J. M. Jones; A. Williams, “Physicochemical characterisation of torrefied biomass”, J. Anal. Appl. Pyrolysis, vol. 103, pp. 21–30, Sep. 2013.

M. Wilk; A. Magdziarz; I. Kalemba, “Characterisation of renewable fuels’ torrefaction process with different instrumental techniques”, Energy, vol. 87, pp. 259–269, Jul. 2015.

R. Correia; M. Gonçalves; C. Nobre; B. Mendes, “Impact of torrefaction and low-temperature carbonization on the properties of biomass wastes from Arundo donax L. and Phoenix canariensis”, Bioresour. Technol., vol. 223, pp. 210–218, Jan. 2017.

D. Chen; K. Cen; X. Jing; J. Gao; C. Li; Z. Ma, “An approach for upgrading biomass and pyrolysis product quality using a combination of aqueous phase bio-oil washing and torrefaction pretreatment”, Bioresour. Technol., vol. 233, pp. 150–158, Jan. 2017.

E. Kemsley; S. Ruault; R. H. Wilson, “Discrimination between Coffea arabica and Coffea canephora variant robusta beans using infrared spectroscopy”, Food Chem., vol. 54, no. 3, pp. 321–326, 1995.

N. Reis; A. S. Franca; L. S. Oliveira, “Discrimination between roasted coffee, roasted corn and coffee husks by Diffuse Reflectance Infrared Fourier Transform Spectroscopy”, LWT - Food Sci. Technol., vol. 50, no. 2, pp. 715–722, Mar. 2013.

R. Cruz et al., “Espresso Coffee Residues: A Valuable Source of Unextracted Compounds”, J. Agric. Food Chem., vol. 60, no. 32, pp. 7777–7784, Aug. 2012.

M. Tariq et al., “Identification, FT-IR, NMR (1H and 13C) and GC/MS studies of fatty acid methyl esters in biodiesel from rocket seed oil”, Fuel Process. Technol., vol. 92, no. 3, pp. 336–341, Mar. 2011.

B. R. Singh; M. A. Wechter; Y. Hu; C. Lafontaine, “Determination of caffeine content in coffee using Fourier transform infra-red spectroscopy in combination with attenuated total reflectance technique: a bioanalytical chemistry experiment for biochemists”, Biochem. Educ., vol. 26, no. 3, pp. 243–247, Jul. 1998.

L. F. Ballesteros; J. A. Teixeira; S. I. Mussatto, “Chemical, Functional, and Structural Properties of Spent Coffee Grounds and Coffee Silverskin”, Food Bioprocess Technol., vol. 7, no. 12, pp. 3493–3503, Jun. 2014.

A. E. Atabani et al., “Valorization of spent coffee grounds recycling as a potential alternative fuel resource in Turkey: An experimental study”, J. Air Waste Manage. Assoc., vol. 68, no. 3, pp. 196–214, Mar. 2018.

W.-H. Chen; K.-M. Lu; C.-M. Tsai, “An experimental analysis on property and structure variations of agricultural wastes undergoing torrefaction”, Appl. Energy, vol. 100, pp. 318–325, Dec. 2012.

T. Melkior; C. Barthomeuf; M. Bardet, “Inputs of solid-state NMR to evaluate and compare thermal reactivity of pine and beech woods under torrefaction conditions and modified atmosphere”, Fuel, vol. 187, pp. 250–260, Jan. 2017.

How to Cite
F. E. Jaramillo, P. N. Alvarado, and R. A. Mazo, “Biomass Torrefaction in a Bench-Scale Screw Reactor: Effect of Temperature and Biomass Type”, TecnoL., vol. 25, no. 54, p. e2269, Jun. 2022.


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