Bio-oil synthesis from Botryococcus braunii by microwave-assisted pyrolysis

Edixon Daniel Ortiz(1), Arief Budiman(2*), Rochim Bakti Cahyono(3)

(1) Chemical Engineering Department, Gadjah Mada University, Jl. Grafika 2, Yogyakarta 55281, Indonesia
(2) Chemical Engineering Department, Gadjah Mada University, Jl. Grafika 2, Yogyakarta 55281, Indonesia
(3) Chemical Engineering Department, Gadjah Mada University, Jl. Grafika 2, Yogyakarta 55281, Indonesia Center of Excellence for Microalgae Biorefinery, Gadjah Mada University, Sekip K1A, Yogyakarta 55281, Indonesia
(*) Corresponding Author


Microalgae have proven to be a promising resource in renewable energy search; Products such as bio-oils could contribute to the replacement of petroleum. The objective of this investigation is to determine the decomposition mechanism, obtain the kinetic reaction, as well as evaluate the potential to obtain microalgae bio-oil through microwave-assisted pyrolysis (MAP). MAP is a new thermochemical conversion from biomass to bio-oil that is faster, efficient, controllable, and flexible, compared to conventional pyrolysis, rapid pyrolysis, or instant pyrolysis. As raw material in this experiment, Indonesian microalgae, Botryococcus braunii was used. The investigation focused on the temperature effect (100-300 °C) and the residence time (10-30 min); a modified microwave oven was used with a power of 900 W. Hexane was used for the extraction of bio- oil. The bio-oil composition was measured with chromatography of mass spectrometry gas (GC-MS) and then this data was used to evaluate a kinetic model and calculate the constant kinetic reaction of the pyrolysis process. The results indicated that bio-oil production begins from 100 °C, however, temperatures between 200-250 °C favor the production of bio-oil, while temperatures above 250 °C and the long residence times prioritize the production of bio-gas. Regarding the kinetic evaluated, the reactions seem to show from third to sixth order with an activation energy (E) of around 30 kj/mol and a pre-exponential factor (ln A) of around 9 s-1. Based on GC-MS Analysis, the bio-oil contains short chain alkanes, cycloalkanes, organic acids as well as aromatic, phenol, benzene compounds. On the other hand, although small amounts of oil were achieved, the decomposition of biomass was up to 50% favoring gas production, these results indicate that MAP has potential in the obtaining of biofuels such as bio-gas and bio-oil.


biofuel; biooil; microalgae; microwave; pyrolysis

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Adam M. 2017. Understanding microwave pyrolysis of biomass materials:1–230.

Ali I, Naqvi SR, Bahadar A. 2018. Kinetic analysis of Botryococcus braunii pyrolysis using model-free and model fitting methods. Fuel. 214(November 2017):369–380. doi:10.1016/j.fuel.2017.11.046.

Banerjee A, Sharma R, Chisti Y, Banerjee UC. 2002. Botryococcus braunii: A renewable source of hydrocarbons and other chemicals. Critical Reviews in Biotechnology. 22(3):245–279. doi:10.1080/07388550290789513.

Bradbury AG, Sakai Y, Shafizadeh F. 1979. A kinetic model for pyrolysis of cellulose. Journal of Applied Polymer Science. 23(11):3271–3280. doi:10.1002/app.1979.070231112.

Bundhoo ZM. 2018. Microwave-assisted conversion of biomass and waste materials to biofuels. Renewable and Sustainable Energy Reviews. 82(September 2017):1149– 1177. doi:10.1016/j.rser.2017.09.066.

de la Hoz A, Díaz-Ortiz À, Moreno A. 2005. Microwaves in organic synthesis. Thermal and non-thermal microwave effects. Chemical Society Reviews. 34(2):164–178. doi: 10.1039/b411438h.

Demirbas A. 2010. Use of algae as biofuel sources. Energy Conversion and Management. 51(12):2738–2749. doi:10.1016/j.enconman.2010.06.010.

Dong Q, Xiong Y. 2014. Kinetics study on conventional and microwave pyrolysis of moso bamboo. Bioresource Technology. 171:127–131. doi:10.1016/j.biortech.2014.08.063.

Fernandez Y, Arenillas A, Angel J. 2011. Microwave heating applied to pyrolysis. Advances in Induction and Microwave Heating of Mineral and Organic Materials. doi:10.5772/13 548.

Huang YF, Chen WR, Chiueh PT, Kuan WH, Lo SL. 2012. Microwave torrefaction of rice straw and pennisetum. Bioresource Technology. 123:1–7. doi:10.1016/j.biortech.2012.08.006.

Huang YF, Chiueh PT, Kuan WH, Lo SL. 2013. Microwave pyrolysis of rice straw: Products, mechanism, and kinetics. Bioresource Technology. 142:620–624. doi:10.1016/j.bior tech.2013.05.093.

Lee J, Kwon EE, Park YK. 2019. Recent advances in the catalytic pyrolysis of microalgae. Catalysis Today. (December 2018):0–1. doi:10.1016/j.cattod.2019.03.010.

Lin B, Li H, Chen Z, Zheng C, Hong Y, Wang Z. 2017. Sensitivity analysis on the microwave heating of coal: A coupled electromagnetic and heat transfer model. Applied Thermal Engineering. 126:949–962. doi:10.1016/j.appltherma leng.2017.08.012.

Marcilla A, Catalá L, García-Quesada JC, Valdés FJ, Hernández MR. 2013. A review of thermochemical conversion of microalgae. Renewable and Sustainable Energy Reviews. 27:11–19. doi:10.1016/j.rser.2013.06.032.

Satpathy SK, Tabil LG, Meda V, Naik SN, Prasad R. 2014. Torrefaction of wheat and barley straw after microwave heating. Fuel. 124:269–278. doi:10.1016/j.fuel.2014.01.102.

Wang MJ, Huang YF, Chiueh PT, Kuan WH, Lo SL. 2012. Microwave-induced torrefaction of rice husk and sugarcane residues. Energy. 37(1):177–184. doi:10.1016/

Wu C, Budarin VL, Gronnow MJ, De Bruyn M, Onwudili JA, Clark JH, Williams PT. 2014. Conventional and microwave-assisted pyrolysis of biomass under different heating rates. Journal of Analytical and Applied Pyrolysis. 107:276–283. doi:10.1016/j.jaap.2014.03.012.

Zhao X, Wang M, Liu H, Li L, Ma C, Song Z. 2012. A microwave reactor for characterization of pyrolyzed biomass. Bioresource Technology. 104:673–678. doi:10.1016/j.biortech.2 011.09.137.


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