Study On Thermal Utilazisition Of Sludge Blended With Municipal Solid Waste/Biomass

With speeding up of urbanization and industrialization in China, the production of sludge after wastewater treatment is huge, which will cause severe environmental pollution without effective treatment, while the current treatment facilities is limited. But auxiliary fuels are needed to add to sludge to ensure the stability of the combustion condition. With rising residents’ living standards and expanding population, yield and calorific values of municipal solid waste increase sharply, which is a kind of auxiliary fuel with more development potential. In addition, as one of a representative of the second generation biomass energy, with the favorable characteristics of high yield, high calorific value and high energy efficiency, it will become a greatly potential biomass energy crops for development and utilization. Therefore, study on co-combustion or co-pyrolysis of paper mill sludge with municipal solid waste/miscanthus, mixed combustion and pyrolysis characteristics of miscanthus has important theoretical and practical significance.The thermogravimetric analyzer was used to study combustion characteristics of paper mill sludge, municipal solid waste and their blends under different blending ratio, the interactions and dynamics analysis in the reaction process. Results showed that the combustion characteristic of municipal solid waste was superior to sludge. When blending ratio of municipal solid waste were more than 30%, blends had good comprehensive combustion characteristic. Interactions existed in the combustion process blends, main promoting effect especially at low temperature stage, but when the blending ratios were more than 70%, inhibition effects existed in the high temperature stage. When the blending ratio were 10%, 30% and 70%, apparent activation energy of blends were lower than that of sludge and municipal solid waste, 70% of municipal solid waste may be the ideal blending ratio.The thermogravimetric analyzer was used to study combustion characteristics of paper mill sludge, miscanthus and their blends under different blending ratio and heating rate, the interactions and dynamics analysis in the reaction process. Results showed that the combustion characteristics of miscanthus was superior to sludge. The increase of heating rate improved the combustion weight loss rate of blends. When blending ratios of miscanthus were more than 50%, blends had good comprehensive combustion characteristic. When the blending ratio was 70%, apparent activation energy of blend was lower than the corresponding values of individual samples, 70% miscanthus may be the better blending ratio.Thermogravimetric and infrared method were adapted to study pyrolysis characteristics of paper mill sludge, miscanthus and their blends under different blending ratio and heating rate, the interactions and dynamics analysis in the reaction process. Results showed that the pyrolysis characteristics of miscanthus was superior to the sludge. In CO2 atmosphere, reduction reaction of coke and CO2 will happen at high temperature. The increase of heating rate improved pyrolysis weight loss rate. There esisted inhibiting effect at low and medium temperature stage. There mainly esisted promoting effect at high temperature stage.When miscanthus blending ratios were more than 30%, pyrolysis performance of blends were better. When blending ratio was 50%, the apparent activation energy obtained the minimal, 50% was likely to be the optimal blending ratio of miscanthus in pyrolysis process. Main products of sludge pyrolysis were CO, HCN, HNCO, NH3, CO2 and H2 O, while main products of miscanthus pyrolysis were methane and other hydrocarbons, CO, HCN, NH3, CO2 and H2 O. The product variation trend of C-H、CO2、CO、C=O、C-O、NH3 was in accord with DTG curves, which were increased with the increasing blending ratio of miscanthus.