| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 87 === Abstract There are three types of commercial SO2 removal system: (1) Dry process, (2) Semi-dry process, and (3) Wet scrubbing process. The calcium utilization and SO2 removal efficiency are low for the dry process. For the semi-dry process, the calcium utilization is higher, but fouling and corrosion of the nozzles and the reactor could be severe. For the wet scrubbing system, a wastewater treatment system is required.The problems mentioned above can be eliminated if gas-solid fluidized bed reactor is used as the desulfurization apparatus. The advantages of the gas-solid fluidized bed reactor are: (1) The desulfurization products are dry so that we do not need a wastewater treatment unit. (2) The bed structure is simple, the equipment cost is low and easy to operate and maintain. (3) The calcium utilization is increased by the special attrition and elutriation mechanism of the fluidized bed, thus the cost of operation is decreased. Therefore, fluidized bed desulfurization technology is worthy of study and development.A bubbling fluidized bed reactor is used as the desulfurization apparatus in this study. The height of the bed is 2.5m, and the diameter is 9cm. The bed material is hydrated lime and silica sand. The effects of the operating parameters of flue gas desulfurization including relative humidity, temperature, superficial gas velocity, the weight ratio of hydrated lime and silica sand, and particle size on SO2 removal efficiency and calcium utilization in the fluidized bed will be investigated.We find temperature effect in our system is negligible from 40 to 65oC. Higher relative humidity has higher calcium utilization (R.H.=20%-80%) and higher sulfur dioxide removal efficiency. Smaller diameter of calcium hydroxide has higher calcium utilization and higher sulfur dioxide removal efficiency. The optimum weight ratio of silica sand and calcium hydroxide is 3. Although the lower superficial gas velocity causes the higher sulfur dioxide removal efficiency and higher calcium utilization, but the SO2 treated volume is maximum when the superficial gas velocity is minimum fluidization velocity. Finally, the attrition rate model by Lee et al. (1993) can predict our bed weight precisely and the value of ko is 9.48×10-6 (s-1) and Ea = 4.69×10-4 (kJ/kg).
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