%0 Journal Article
%T Experimental Investigation of Thermal Characteristics of Kiwira Coal Waste with Rice Husk Blends for Gasification
%A Deodatus Kazawadi
%A Geoffrey R. John
%A Cecil K. King¡¯ondu
%J Journal of Energy
%D 2014
%R 10.1155/2014/562382
%X Eminent depletion of fossil fuels and environmental pollution are the key forces driving the implementation cofiring of fossil fuels and biomass. Cogasification as a technology is known to have advantages of low cost, high energy recovery, and environmental friendliness. The performance/efficiency of this energy recovery process substantially depends on thermal properties of the fuel. This paper presents experimental study of thermal behavior of Kiwira coal waste/rice husks blends. Compositions of 0, 20, 40, 60, 80, and 100% weight percentage rice husk were studied using thermogravimetric analyzer at the heating rate of 10£¿K/min to 1273£¿K. Specifically, degradation rate, conversion rate, and kinetic parameters have been studied. Thermal stability of coal waste was found to be higher than that of rice husks. In addition, thermal stability of coal waste/rice husk blend was found to decrease with an increase of rice husks. In contrast, both the degradation and devolatilization rates increased with the amount of rice husk. On the other hand, the activation energy dramatically reduced from 131£¿kJ/mol at 0% rice husks to 75£¿kJ/mol at 100% rice husks. The reduction of activation energy is advantageous as it can be used to design efficient performance and cost effective cogasification process. 1. Introduction The ever increasing need for clean energy, environmental protection, and alternative use of fossil fuel has necessitated the recovery of energy from waste fossil energy resources. Efficient ways to recover damped coal waste are on record and range from circulating fluidized bed combustor to gasification and pyrolysis [1]. Tanzania has approximately 1.5 billion metric tons of proven coal [2] with Kiwira coal mine having a proven deposit of 4 million metric tons [3]. It has an annual coal waste production of 17,374 tons [4] and has damped over 500,000 metric tons of waste for the 2 million metric tons of coal already mined. Although Tanzania has reasonably enough unutilized fresh coal, effective use of coal waste can provide sustainable profile of fossil fuel use. Tanzania has a wide range of biomass including forestry and agricultural residue. Rice husk in Tanzania is not used efficiently and as such most of it is wasted. For example, Mhilu estimated 326,220 tons of rice husks are wasted annually compared to 10,400 tons of coffee husks [5]. Direct combustion of coal waste has a wide range of constraints from environmental pollution, low energy recovery, and high cost [1]. Proven, cheap, and environmental friendly technologies such as
%U http://www.hindawi.com/journals/jen/2014/562382/