Thermal Degradation and Kinetics of Rice Husk

Abstract

The trend for material and energy recovery from biomass-waste along with the need to reduce green house gases has led to an increased interest in the thermal processes applied to biomass. The thermal process applied to biomass produces either liquid fuel (bio-oil) or gaseous fuel. One of the biomass wastes that are produced in Tanzania is rice husk. It can be used either in pyrolysis and gasification process. In order to undertake a parametric study on the fast pyrolysis of rice husk, it is imperative to establish its thermal characteristics. The paper reports thermal degradation and kinetics of rice husk. The thermal degradation was conducted in a thermo-gravimetric analyzer from room temperature to 1273 K at different heating rates. The rice husk was observed to be suitable for gasification since it contains high ash content of 22.21% and fixed carbon of 12.60%. The suitable heating rate for high degradation of rice husk is 10 K/min, which has peak temperature at 633 K. The resulting activation energy of 180.075 kJ/mol and pre-exponential factor of 2.401E+27 s-1 was determined.

Keywords

• Gasification; Kinetics; Pyrolysis; Rice husk; Thermal degradation

References

1. D. Mohan, C. Pittman, and P. Steele, Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review., Journal of Energy & Fuel, Vol. 20, pp. 848 – 889, 2006.
2. P. Basu, Biomass Gasification and Pyrolysis Practical Design and Theory, Elsevier Inc, United State (2006), ch 2-3.
3. F. Gwang'ombe and N. Mwihava, Renewable in Tanzania: Status and Prospects of Biomass Based Cogeneration and Geothermal Technologies. HBF-HA, Sida/SAREC www.afrepren.org, 2005. AFREPREN/FWD,
4. H. Goyal, D. Seal, and R. Saxena, Bio-fuels from thermochemical conversion of renewable resources: A review, Journal of Renewable energy review, Vol. 12 pp 504-517, 2008.
5. J. Cai , L. Bi Precision of the Coats and Redfern method for the determination of activation energy without neglecting the low temperature end of the temperature integral, Energy & Fuels, 22, pp. 2172-2174, 2008.
6. M. Safi , I. Mishra , B. Prasad, Global degradation kinetics of pine needles in air, Thermochimica Acta, 412, pp. 155/162, 2004.
7. Criado J., Dollimore D., Heal G. Critical study of the suitability of the Freeman and Carroll method for the kinetic decomposition of solids, Thermochimica Acta, 54, pp. 159-165, 1982. the reactions of thermal
8. J. Criado , A. Ortega, Non isothermal transformation kinetics: Remarks on Kissinge method, Journal of Non Crystalline Solid, 87, pp. 302-311, 1986.

9. A. Tsamba, Fundamental study of two selected tropical biomass for energy: Coconut and cashew nut shells, Doctoral Thesis, Energy and Furnace Technology, Stockholm, Sweden, 2008 .
10. Aho M., Tummavuon J., Hamalainem J., and Saastamoinem J. Determination of Heat of Pyrolysis and Thermal reactivity of Peats, Journal of Fuel, Volume 68, pp 1106-1111, 1989.
11. Reading M., Elliot D., and Hill V., A New Approach to the Calorimetric Investigation of Physical and Chemical Transitions, Journal of Thermal Analysis, Volume 40, pp 949-955, 1993.
12. C. Di Blasi, Modeling Chemical and Physical Processes of Wood and Biomass Pyrolysis. Progress in Energy and Combustion Science, 34, 47-90, 2008.