There increasing demand for technologies that are capable of producing heat and electric energy by burning fuels such as solid refuse fuel (SRF) and biomass to mitigate the effects of greenhouse gas emissions from fossil fuels and global warming in the field of thermal power generation. In particular, conversion of SRF into energy (Waste to Energy) is the promising technology with high economic and social benefits. The high temperature corrosion of the heat exchange tube is the most important factor that affects the economic deterioration of a circulating fluidized bed boiler using solid refuse fuel, due to operating time decrease and the periodic shutdown during plant operation. The purpose of this study was to examine the high temperature corrosion characteristics of boiler superheater tubes. The change of corrosion characteristics according to the temperature and alkali chloride salt can be investigated by analyzing the morphology of the surface and the microstructure of specimen cross-section and examining the changes in the physical and chemical properties. The degree of corrosion increased as the temperature increased and the weight of the alkali chloride specimen deposit decreased due to the volatilization of the metal chloride compound above 700°C. Deposits of KCl were found to accelerate corrosion by destroying the oxide layer and forming potassium compounds.

Bio-SRF (Bio-Solid Refuse Fuel) based on livestock waste has a low heating value and high moisture content. The concentration of toxic gas, such as SOx, NOx, and HCl, in the flue gas is changed according to the composition of fuel, which has been reported. Therefore, the study of fuel combustion characteristics is necessary. Additionally, the study of fuel firing characteristics is necessary. In this study, we investigated the combustion characteristics of the mixed firing of coal and Bio-SRF made from livestock waste in a circulating fluidized bed combustor (CFBC). The Bio-SRF of livestock waste was mixed with different ratios of coal based on the heating values when the coal was completely combusted in CFBC. In the results of the experiment, the combustor efficiencies of the calculated unburned carbon concentration in the fly ash were 98.87%, 99.04%, 99.64%, and 99.71% when the multi-firing ratio of livestock sludge increased from 100/0 to 70/30. In addition, the boiler efficiencies were 86.23%, 86.30, 87.24, and 87.27%. Through the experimental results, we identified that the mixed combustion of livestock sludge is not affected by boiler efficiency. We have systematically investigated and discussed the temperature changes of an internal combustor, compositions of flue gases, solid ash characteristics, and the combustion and boiler efficiency during the mixed firing of coal and Bio-SRF.

In this study, the experiments which use the dry absorbent has been executed in order to find optimum HCl absorptionconditions. The absorbents in this experiment were Ca(OH)2-A, Ca(OH)2-B and CaO. They were put in a fixed-bed reactor.The reaction temperature of HCl/Ca(OH)2 systems were between 200~400oC and those of HCl/CaO systems werebetween at 500~700oC. The reaction gases were HCl and N2 mixtures (3000ppm). The reaction gas of 2L·min−1 wasfed into the reactor. As temperature increased, the conversion ratio of HCl in Ca(OH)2 particles also increased.Consequently, Ca(OH)2-B showed the maximum conversion ratio of 19% at 400oC. CaO also showed the similar tendencywith the result of Ca(OH)2. In case of same particle sizes, as reaction temperature increased, the reaction rate constant(k) also increased. The highest reaction rate constant of Ca(OH)2-B was 3,952min−1 at 400oC. All absorbents in thisexperiment showed that the reaction rate decreased with increasing the size of the particles at each temperature condition.The kinetics of the reaction between sorbents and HCl molecules showed that the activation energies were about 2.71~6.85kcal·mol−1 (averager 4.53kcal·mol−1) for Ca(OH)2-A, about 1.3011.51kcal·mol−1 (average 6.10kcal·mol−1) forCa(OH)2-B, and about 2.5314.3kcal·mol−1 (average 6.91kcal·mol−1) for CaO depending on conversion ratios.