Host: The Society of Chemical Engineers, Japan
In this study, the reaction mechanism of limestone and Cl compounds was investigated by using fixed bed plug flow reactor. Trichloroethane(TCE) was identified as one of the Cl compounds emitting during the pyrolysis of model-RDF at 500°C 1), so TCE was chosen as the model compound of organic Cl compounds, and HCl was used as that of inorganic Cl compounds. Under any the partial pressure of steam, TCE and HCl were reacted with both CaO and Ca(OH)2. Products of each reaction were identified by X-ray diffraction. Moreover by changing the injection volume of Cl compounds, the Cl absorption mechanisms of CaO and Ca(OH)2 were investigated. The reaction of TCE with CaO was not observed. On the other hand, the product of TCE with Ca(OH)2 was identified as CaClOH. And when the volume of TCE injection was increased, only CaClOH was identified. So, no further dechlorination was occurred. The products of HCl reaction with CaO were identified as CaCl2 and CaCl2·2H2O. When the steam was added, the HCl reaction with Ca(OH)2 was occurred, the product was identified as CaClOH and when the injection volume of HCl was increased, identified as CaCl2, CaCl2·2H2O. That is to say, more dechlorination was occurred differently from TCE reactions with both CaO and Ca(OH)2. CaClOH was also proposed as a product of HCl reaction with CaO, because the reaction of CaO with H2O resulting from HCl reaction with CaO was occurred and the same time, HCl reaction with Ca(OH)2 was also occurred. At high temperature(800°C), the reaction of TCE with limestone was considered as the reaction of HCl generated from decomposition of TCE with limestone, and it was considered that both the reaction of TCE with Ca(OH)2 and that of HCl with CaO or Ca(OH)2 were occurred at 650°C.
