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A Comparative Study on Biochar from Slow Pyrolysis of Corn Cob and Cassava Wastes

Authors: Adilah Shariff, Nurhidayah Mohamed Noor, Alexander Lau, Muhammad Azwan Mohd Ali


Biomass such as corn and cassava wastes if left to decay will release significant quantities of greenhouse gases (GHG) including carbon dioxide and methane. The biomass wastes can be converted into biochar via thermochemical process such as slow pyrolysis. This approach can reduce the biomass wastes as well as preserve its carbon content. Biochar has the potential to be used as a carbon sequester and soil amendment. The aim of this study is to investigate the characteristics of the corn cob, cassava stem, and cassava rhizome in order to identify their potential as pyrolysis feedstocks for biochar production. This was achieved by using the proximate and elemental analyses as well as calorific value and lignocellulosic determination. The second objective is to investigate the effect of pyrolysis temperature on the biochar produced. A fixed bed slow pyrolysis reactor was used to pyrolyze the corn cob, cassava stem, and cassava rhizome. The pyrolysis temperatures were varied between 400 °C and 600 °C, while the heating rate and the holding time were fixed at 5 °C/min and 1 hour, respectively. Corn cob, cassava stem, and cassava rhizome were found to be suitable feedstocks for pyrolysis process because they contained a high percentage of volatile matter more than 80 mf wt.%. All the three feedstocks contained low nitrogen and sulphur content less than 1 mf wt.%. Therefore, during the pyrolysis process, the feedstocks give off very low rate of GHG such as nitrogen oxides and sulphur oxides. Independent of the types of biomass, the percentage of biochar yield is inversely proportional to the pyrolysis temperature. The highest biochar yield for each studied temperature is from slow pyrolysis of cassava rhizome as the feedstock contained the highest percentage of ash compared to the other two feedstocks. The percentage of fixed carbon in all the biochars increased as the pyrolysis temperature increased. The increment of pyrolysis temperature from 400 °C to 600 °C increased the fixed carbon of corn cob biochar, cassava stem biochar and cassava rhizome biochar by 26.35%, 10.98%, and 6.20% respectively. Irrespective of the pyrolysis temperature, all the biochars produced were found to contain more than 60 mf wt.% fixed carbon content, much higher than its feedstocks.

Keywords: Biochar, biomass, cassava wastes, corn cob, pyrolysis.

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[1] Potsdam Institute for Climate Impact Research and Climate Analytics (PIK), Turn Down the Heat: Why a 4 °C Warmer World Must be Avoided. Washington, DC: World Bank, 2012.
[2] Department of Statistics Malaysia (DOSM), Compendium of Environment Statistics Malaysia 2011. Malaysia: DOSM, 2011.
[3] The Intergovernmental Panel on Climate Change (IPCC), Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, C. W. Team, R. K. Pachauri, and L. A. Meyer, Eds. Geneva, Switzerland: IPCC, 2014.
[4] D. Woolf, J. E. Amonette, F. A. Street-Perrott, J. Lehmann, and S. Joseph, “Sustainable biochar to mitigate global climate change,” Nat. Commun., vol. 1, no. 56, pp. 1−9, 2010.
[5] E. Cushion, A. Whiteman, and G. Dieterle, Bioenergy Development: Issues and Impacts for Poverty and Natural Resource Management. Washington, DC: World Bank, 2010.
[6] J. Lehmann, J. Gaunt, and M. Rondon, “Bio-char sequestration in terrestrial ecosystems - A review,” Mitigation Adapt. Strateg. Glob. Chang., vol. 11, pp. 403−427, 2006.
[7] International Biochar Initiative (IBI), Biochar: A Soil Amendment that Combats Global Warming and Improves Agricultural Sustainability and Environmental Impacts. 2009.
[8] J. Lehmann, and S. Joseph, “Biochar for environmental management: An introduction” in Biochar for Environmental Management Science, Technology and Implementation, 2nd ed., J. Lehmann and S. Joseph, Eds. New York: Routledge, 2015, pp. 1−12.
[9] J. Lehmann, “Bio-energy in the black,” Front. Ecol. Environ., vol. 5, no. 7, pp. 381−387, 2007.
[10] F. Verheijen, S. Jeffery, A. C. Bastos, M. van der Velde, and I. Diafas, Biochar Application to Soils - A Critical Scientific Review of Effects on Soil Properties, Processes and Functions, EUR 24099 EN, Luxembourg: Office for Official Publications of the European Communities, 2010.
[11] E. Krull, Notes on Biochar. The Commonwealth Scientific and Industrial Research Organisation (CSIRO), 2009.
[12] S. Joseph, C. Peacocke, J. Lehmann, and P. Munroe, “Developing a biochar classification and test methods” in Biochar for Environmental Management: Science and Technology, J. Lehmann and S. Joseph, Eds. UK and USA: Earthscan, 2009, pp. 107−112.
[13] H. McLaughlin, Characterizing Biochars Prior to Addition to Soils: Version 1. Alterna Biocarbon Inc., 2010.
[14] O. Mašek, P. Brownsort, A. Cross, and S. Sohi, “Influence of production conditions on the yield and environmental stability of biochar,” Fuel, vol. 103, pp. 151−155, 2013.
[15] M. I. Jahirul, M. G. Rasul, A. A. Chowdhury, and N. Ashwath, “Biofuels production through biomass pyrolysis - A technological review,” Energies, vol. 5, pp. 4952−5001, 2012.
[16] A. Downie, A. Crosky, and P. Munroe, “Physical properties of biochar” in Biochar for Environmental Management: Science and Technology, J. Lehmann and S. Joseph, Eds. UK and USA: Earthscan, 2009, pp. 14–32.
[17] M. Balat, M. Balat, E. Kirtay, and H. Balat, “Main routes for the thermo-conversion of biomass into fuels and chemicals. Part 1: Pyrolysis systems,” Energy Convers. Manage. , vol. 50, no. 12, pp. 3147−3157, 2009.
[18] R. Brown, “Biochar production technology” in Biochar for Environmental Management: Science and Technology, J. Lehmann and S. Joseph, Eds. UK and USA: Earthscan, 2009, pp. 127−146.
[19] D. Mohan, C.U. Pittman, and P.H. Steele, “Pyrolysis of wood/biomass for bio-oil - A critical review,” Energy Fuels, vol. 20, no. 3, pp. 848−889, 2006.
[20] International Biochar Initiative (IBI), Feedstocks. 2013.
[21] Food and Agriculture Organization of the United Nations (FAO), Dimensions of Need: An Atlas of Food and Agriculture, T. Loftas and J. Ross, Eds. Rome, Italy: FAO, 1995.
[22] Food and Agriculture Organization of the United Nations (FAO), FAO Statistics Division. 2016.
[23] ASTM E1756-08: Standard Test Method for Determination of Total Solids in Biomass. ASTM International, 2008.
[24] ASTM E872-82: Standard Test Method for Volatile Matter in the Analysis of Particulate Wood Fuels. ASTM International, 2006.
[25] ASTM E1755-01: Standard Test Method for Ash in Biomass. ASTM International, 2007.
[26] ASTM D1107-96: Standard Test Method for Ethanol-Toluene Solubility of Wood. ASTM International, 2013.
[27] ASTM D1106-96: Standard Test Method for Acid-Insoluble Lignin in Wood. ASTM International, 2013.
[28] ASTM D1104-56: Method of Test for Holocellulose in Wood. ASTM International, 1978.
[29] ASTM D1103-60: Method of Test for Alpha-Cellulose in Wood. ASTM International, 1977.
[30] Vieweg, “Heat, fire and stoves” in Fuel-Saving Cook Stoves. Aprovecho Institute, 1984.
[31] A. Demeyer, J. C. Voundi Nkana, and M. G. Verloo, “Characteristics of wood ash and influence on soil properties and nutrient uptake: An overview,” Bioresour. Technol., vol. 77, no. 3, pp. 287−295, 2001.
[32] P. A. Brownsort, Biomass Pyrolysis Processes Review of Scope, Control and Variability. UKBRC Working Paper 5, 2009.
[33] K. Azduwin, M. J. M. Ridzuan, S. M. Hafis, and T. Amran, “Slow pyrolysis of imperata cylindrica in a fixed bed reactor,” Int. J. Biol. Ecol. Environ. Sci., vol. 1 no. 5, pp. 176−180, 2012.
[34] S. Uçar, and S. Karagöz, “The slow pyrolysis of pomegranate seeds: The effect of temperature on the product yields and bio-oil properties,” J. Anal. Appl. Pyrolysis, vol. 84, no. 2, pp. 151−156, 2009.
[35] N. Claoston, A. W. Samsuri, M. H. A. Husni, and M. S. M. Amran, “Effects of pyrolysis temperature on the physicochemical properties of empty fruit bunch and rice husk biochars,” Waste Manage. Res., vol. 33, no. 3, pp. 275–283, 2014.
[36] P. A. Horne, and P.T. Williams, “Influence of temperature on the products from the flash pyrolysis of biomass,” Fuel, vol. 75, no. 9, pp. 1051−1059, 1996.
[37] M. Nik-Azar, M. R. Hajaligol, M. Sohrabi, and B. Dabir, “Mineral matter effects in rapid pyrolysis of beech wood,” Fuel Process. Technol., vol. 51, no. 1–2, pp. 7–17, 1997.
[38] C. Gheorghe, C. Marculescu, A. Badea, and T. Apostol, “Pyrolysis parameters influencing the bio-char generation from wooden biomass,” U. P. B. Sci. Bull., series C, vol. 72, no. 1, pp. 29–38, 2010.
[39] A. Paethanom, and K. Yoshikawa, “Influence of pyrolysis temperature on rice husk char characteristics and its tar adsorption capability,” Energies, vol. 5, no. 12, pp. 4941−4951, 2012.