Co-combustion Interactions between Teak Sawdust and Sewage Sludge with Additives

The thermal characteristics and kinetics of teak sawdust (TS), sewage sludge (SS), and their blends were evaluated during combustion by thermogravimetric analysis (TGA). The samples were prepared as pure fuel, TS and SS; blends, where TS was mixed with SS at the ratios of 75:25, 50:50, and 25:75; and as fuels with additives, where the fuels above were mixed with activated carbon (AC), CaO, MgO, and ZnO individually at a proportion of 5 wt%. Some characteristic values of combustion were evaluated, such as Ti, Tb, and Mf, and the combustion behaviors of the fuels were compared. The difference between measurement and weighted calculation of the weight left proportion (∆M), weight loss rate (∆DTG), and activation energy (∆E) were introduced for analysis. Blending with teak sawdust improved the combustion performance of sewage sludge. As the content of the sewage sludge increased, the pre-exponential factor varied from 1.76 x 105 s-1(100T) to 1.01 x 101 s-1(100S), while the global activation energy decreased from 74 kJ/mol (100T) to 38 kJ/mol (100S). Sewage sludge burned more completely when blended with teak sawdust at ratios of greater than 50 wt%. All four additives inhibited the oxidation of the blends around the ignition point.