Simultaneous Drying and Torrefaction Pretreatment of Organic Waste for Upgrading Calorific Value

Jakkrit Saengpeng, Kittisak Khuwaranyu, Duangkamol Ruen-ngam


Nowadays, renewable energy is of great interest to the world because it reduces greenhouse gas emission (GHG). Torrefaction is a thermochemical pretreatment process that converts biomass into biocoal. Recently, this technology was used during a study where organic waste, a type of biomass, was the focus of the experiment for upgrading biomass. The aim of this research is to evaluate the possibility of whether or not such technology can effectively be used to modify organic waste. Applying systematic composite sampling, the researcher discovered that the top four varieties of high contents were mostly vegetables: cabbage, nappa cabbage, morning glory and kale. The experiment was conducted using a universal oven with a heating rate of around 7.22°C/min and a controlled air flow rate of 40%. The temperature was set at a controlled range of 80-300°C and time was set in the range of 0-15 hours. A product called biocoal had a high heating value (HHV) of around 20.08 MJ/kg. Pretreated cabbage samples had a heating value 2.2 times higher than that of an unpretreated sample. The second test samples: nappa cabbage, kale, and morning glory had higher HHV values than unpretreated samples at 1.8, 1.8 and 1.4 times, respectively.


Biomass; Drying; High heating value; Organic waste; Torrefaction

Full Text:



International Energy Agency. World Energy Outlook. 2007.

United Nations (UN). 1998. Kyoto protocol to the United Nations framework convention on climate change, Retrieved 3 August 2021 from the World Wide Web:

Zwart R.W.R., Boerrigter H., van der Drift A., 2006. The impact of biomass pretreatment on the feasibility of overseas biomass conversion to Fischer-Tropsch products. Energy Fuels 20: 2192-7.

U.S. Energy Information Administration. 2017. Today in energy, Biomass and waste fuels made up 2% of total U.S. electricity generation in 2016, Retrieved 31 July 2021 from the World Wide Web:

National Development and Reform Commission. Mid-long term development plan for renewable energy 2007. Retrieved 3 August 2021 from the World Wide Web:

Energy Policy and Planning Office (EPPO, Ministry of Energy. 2018. Thai Integrated Energy Blueprint (TIEB), THAILAND: Alternative Energy Development Plan 2018-2037 (AEDP 2018-2037). Retrieved 31 July 2021 from the World Wide Web:

Duangkamol R., 2018. Planning and Budget Department, Division of Planning and Budgeting Local Development Plan 2018-2022, review [On-line serial], Retrieved July 31 2019 from the World Wide Web:

Singh D. and S. Yadav.2021. Evaluation of the physico-chemical development of kitchen food wastes through torrefaction - a biodiversity case study. Biomass Conversion and Biorefinery 11: 1353-1362.

Niu Y., Lv Y., Lei Y., Liu S., Liang Y., Wang D. and Hui S., 2019. Biomass torrefaction: properties, applications, challenges, and economy. Renewable and Sustainable Energy Reviews 115: 109395.

Matsakas L., Gao Q., Jansson S., Rova U., and Christakopoulos P., 2017. Green conversion of municipal solid wastes into fuels and chemicals, Review. Electronic Journal of Biotechnology 26: 69–83.

Poudel J., Ohm T., and Oh S.C., 2015. A study on torrefaction of food waste. Fuel 140: 275–281.

Klinghoffer N.B. and M.J. Castaldi. 2013. Gasification and pyrolysis of municipal solid waste (MSW), waste to energy conversion technology, Woodhead Publishing Series in Energy 146–176.

Mohammad M., Ozbay I., and Durmusoglu E., 2017. Bio-drying of green waste with high moisture content. Process Safety and Environmental Protection 111: 420–427.

Basu P., 2010. Biomass Gasification and Pyrolysis; Oxford: Elsevier Inc.

Berge N., Ro K.S., Mao J., Flora J.R.V., Chappell M.A. and Bae S., 2011. Hydrothermal carbonization of municipal waste streams, Environmental Science and Technology 45: 5696–703.

Soponpongpipat N., Nanetoe S., and Comsawang P., 2020. Thermal degradation of cassava rhizome in thermosyphon-fixed bed torrefaction reactor. Processes 8: 267.

Manatura K., 2020. Inert torrefaction of sugarcane bagasse to improve its fuel properties. Case Studies in Thermal Engineering 19: 100623.

ASTM International, 2013. Standard method for moisture analysis of particulate wood fuels; ASTM E 871-82, ASTM International, Pennsylvania, USA.

ASTM International, 1987. Standard test method for volatile matter in the analysis of particulate wood fuels E-872, ASTM International, Pennsylvania, USA.

ASTM International, 2008. Standard test method for ash in wood; ASTM D 1102, ASTM International, Pennsylvania, USA.

AOAC, 2016. Standard Test Method for Amylase-treated neutral detergent fiber in feeds, AOAC Official Method 2002.04, AOAC Office, MD, USA.

AOAC, 2016. Standard test method for fiber (acid detergent) and lignin (H2SO4) in animal feed, AOAC official method 973.18, AOAC Office, MD, USA.

ASTM International, 2004. Standard test method for ash in wood; ASTM E 711, ASTM International, Pennsylvania, USA.

EPA, 2021. Test methods for evaluating solid waste: United States Environmental Protection Agency 1986, Retrieved 31 July 2021 from the World Wide Web:

Peng J.H., Bi H.T., Sokhansanj S., and Lim J.C., 2012. A study of particle size effect on biomass torrefaction and densification. Energy Fuels 26: 3826-3839.

Chen W., Lin, B., Lin Y., Chu Y., Ubando A.T., Show P.L., Ong H.C., Chang J., Ho S. and Culaba A.B., Pétrissans A., Pétrissans M., 2021. Progress in biomass torrefaction: Principles, applications, and challenges. Progress in Energy and Combustion Science 82: 100887.

Cahyanti M.N., Doddpaneni T.R.K.C. and Kikas T., 2020. Review, Biomass torrefaction: an overview on process parameters, economic and environmental aspects and recent advancements, Bioresource Technology 301: 122737.

Chen W., Lu K., and Tsai C., 2012. An experimental analysis on property and structure variations of agricultural wastes undergoing torrefaction. Applied Energy 100: 318–325.

Singh R.K., Sarkar A., and Chakraborty P.J., 2019. Effect of torrefaction on the physicochemical properties of pigeon pea stalk (Cajanus cajan) and estimation of kinetic parameters. Renewable Energy 138: 805-819.

Morato T., Vaezi M., and Kumar A., 2019. Assessment of energy production potential from agricultural residues in Bolivia. Renewable and Sustainable Energy Reviews 102: 14-23.

Vassilev S.V., Baxter D., Andersen L.K., and Vassieva C.G., 2010. An overview of the chemical composition of biomass. Fuel 89: 913-33.

Nobre C., Vilarinho C., Alves O., Mendes B., and Gonҫalves M., 2019. Upgrading of refuse derived fuel through torrefaction and carbonization: Evaluation of RDF char fuel properties. Energy 181: 66-76.

Wilk M., Magdziarz A., Kalemba I., and Gara P., 2016. Carbonisation of wood residue into charcoal during low temperature process. Renewable Energy 85: 507-13.

Cardona S., Gallego L.J., Valencia V., Martínez E., Rios L.A., and Javier L., 2019. Torrefaction of eucalyptus-tree residues: a new method for energy and mass balances of the process with the best torrefaction conditions. Sustainable Energy Technology Assessments 31: 17-24.