Analysis of Energy Characteristics of Rice and Coffee Husks Blends

Production of first generation biofuels using food crops is under criticism over sustainability issues on food security. Tanzania is showing active interest in developing second generation biofuels to deal with some of such issues, especially from the feedstock point of view. This paper reports work done to determine energy characteristics of rice and coffee husks. The results show that coffee husks have better energy quality than rice husks, while heating values of coffee are 18.34？MJ/kg and 13.24？MJ/kg for rice husk. Thermogravimetric analysis made for coffee husks blended rice husks at a ratio of 75？:？25% vol. show better material degradation characteristics yielding low residual mass of 23.65%, compared to 26.50% of char and ash remaining in pure rice husks. Derivative thermogravimetric analysis shows comparable hemicellulose degradation peak values of ？11.5 and ？11.2 and cellulose ？3.20 and ？2.90 in pure coffee and rice husks, respectively. In coffee and rice husks blends, substantial reductions of hemicellulose and cellulose peaks were observed. Use of coffee and rice husks blends applying high temperature gasification would reduce the latter’s flammability, while increasing its flame retention characteristics, hence offering opportunities for production of clean syngas in a sustainable manner. 1. Introduction 1.1. Background and Goal For many years, we have consumed fossil fuels with no worries about possible shortages, but, now, those same oil fields are running dry, while use of coal as a source of energy is also facing criticisms due to its contribution on environmental pollution. In view of this situation, there has been a growing impetus looking for alternative sources of energy for the future. Biomass based second generation biofuels could partly assist to resolve some of these issues, especially from the feedstock point of view for energy production applying various conversion methods to improve the combustion efficiency. The advantages of using biomass are obvious as this material, is generally left to rot or burnt in an uncontrolled manner, producing CO2 as well as smoke. Most African countries are facing problems of inadequate access to modern sources of energy. The United Republic of Tanzania being one of the sub-Saharan African countries is showing active interest in the development of the second generation biofuels, especially from the feedstock point of view to address criticism over sustainability issues as well as arguments on food security arising from the production of 1st generation biofuels derived from food crops materials to