Simultaneous Decomposition and Fixation of F-Gases Using Waste Concrete

Abstract

Experimental study was conducted on the simultaneous process of decomposition and fixation of fluoride of F-gases. HFC-134a, a hydrofluorocarbon (HFC), used most widely, was selected as a model gas, and its decomposition performances were examined in a tube type reactor with and without waste concrete powder. Decomposition of HFC-134a was observed at temperatures above 500 °C, while no thermal decomposition occurred below 750 °C without waste concrete. The results for the differential type reactor with high SV demonstrated that the calcium reaction ratio in the waste concrete reached about 50 mol % after 10 min of reaction. Thermal decomposition of HFC-134a was promoted by increasing the reaction temperature. The particle size of the waste concrete within the range studied scarcely affected the decomposition rate. An increase in HFC-134a concentration resulted in a higher calcium reaction ratio of waste concrete. For the integral reactor conditions with packed bed of waste concrete, almost all HFC-134a in the feed gas could be decomposed until 20 min of the reaction time.