Biomass material as a source of fuel is difficult to handle, transport, store, and utilize in its original form. To overcome these challenges and make it suitable for energy prodution, the material must be pre-treated. Biomass steam explosion is one of the promising pretreatment methods where moisture and hemicellulose are removed in order to improve biomass storage and fuel properties. This paper is aimed to model the suitability of pine saw dust for energy production through steam explosion process. The peak property method was used to determine the kinetic parameters. The model has shown that suitable operating conditions for steam explosion process to remove moisture and hemicellulose from pine sawdust. The temperature and pressure ranges attained in the current study are 260 -317 ˚C (533 -590 K), 4.7 -10.8 MPa, respectively.

The study of non-isothermal kinetics analyzed the reactivity of pine sawdust, while the thermodynamic properties analyzed energy consumed and released from the pine sawdust. The kinetic parameters were determined by analyzing mass loss of pine sawdust components by using Thermogravimeric analyzer. The cellulose has the highest conversion rate of 9.5%/min at 610 K compared to hemicellulose and lignin, which are 5%/min at 600 K and 2%/min at 800 K, respectively. The activation Energy for cellulose, hemicellulose and lignin was 457.644, 259.876, and 89.950 kJ/mol, respectively. The thermodynamic properties included the change of Gibbs free energy for cellulose and hemicellulose, which were −214.440 and −30.825 kJ/mol respectively, their degradation was spontaneous in forward direction, while change of Gibbs free energy for lignin was 207.507 kJ/mol, which is non-spontaneous reaction. The positive value of change of entropies for the active complex compounds formed from hemicellulose and cellulose is less stable, while the active complex compounds of lignin are characterized by a much higher degree of arrangement since its change of entropy is negative. The kinetic and thermodynamic properties show that pine sawdust is a good candidate for production of char since it is easier to remove hemicellulose through thermal process.

Waste resulting from economic activities has been an integral part of every human society. Effective waste management is considered to be consistent with improved quality of life through removal of potential hazards of uncontrolled disposal. Recent years has witnessed a number of sustainable energy recovery technologies developed to divert solid waste destined for landfills. Waste management is a global problem and therefore development of energy recovery technologies and at the same time serving dual purpose in its reduction has become a priority in recent years. The present study reports kinetics properties and thermal behavior of pine sawdust and municipal solid waste (MSW) using thermogravimetric analysis (TGA) and thus providing theoretical basis for development of energy recovery technologies. Results of this study have shown that the activation energy of both MSW and pine sawdust varies with temperature. The analysis of pine sawdust shows that it has activation energy (Ea) values of 26.19 kJ/mol., 87.46 kJ/mol. and 54.46 kJ/mol. At respective temperature ranges between 350 – 400K, 550 – 650K and 700 800K.  MSW has activation energy between 72.91 kJ/mol. and 139.1 kJ/mol. at temperature ranges between 700 – 900 K and 500 – 600 K respectively. The estimated value of pre-exponential factor for pine sawdust was determined to have the values of 2.46 x 104, 1.6 x 1010 and 5.32 x 1016 (s-1) with temperature ranges between 350 – 400 K, 550 – 650 K and 700 800 K respectively. Municipal solid waste has the values of 3.01 x 1012 and 7.31 x 103 (s-1) with a temperature range of 500 – 600 K and 700 – 900 K respectively. From these findings, it has been determined that MSW and pine sawdust available in Arusha and Kilimanjaro possess energy recovery potentials.

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