DE-HCL BY FLUIDIZED BED OF SLAKED LIME IN GASIFICATION PROCESS

摘要

A dry removal process of hydrogen chloride (HCl) is proposed to apply to gasification systems of organic wastes involving biomass. The fuel gas produced by gasification of the wastes contains HCl, which causes not only great damage to gasification equipments but also degradation of performance by corrosion of electrodes especially in the case of the power generation system using a fuel cell (FC). Therefore, it is very important to remove HCl to a significantly low level less than 1 ppm order. In the present work, the reactivity of calcium absorbents is evaluated by the thermogravimetric analysis and the chemical equilibrium consideration. Slaked lime is the most appropriate calcium absorbents for the HCl removal process if the reaction takes place at the temperature of 573 K. It is also found that the high reaction rate is continued until the conversion of chlorination reaction with slaked lime reaches up to 0.6-0.7, and the rate fell down rapidly beyond that effective conversion. This significant reactivity is observed for larger granular particles with the specific pore area of the level of 30 m 2 /g as well. In order to develop the fluidized bed reactor for HCl removal by slaked lime particles based on those knowledge, the performance test of the dechlorination in a lab-scale fluidized bed reactor made of quartz glass tube is carried out by using the slaked lime particles of the median size 130 μm. The HCl concentration of the outlet gas of the fluidized bed is maintained to less than 10 ppm for a certain time depending on the gas velocity after beginning supply of HCl test gas in the reactor until achieving at 0.6 in the conversion of the absorbent, and then made for the breakthrough significantly.