Thermal destruction of HFC-134a in pilot-, and full-scale gasification systems

Abstract There is much interest in reducing hydrofluorocarbon (HFC) emissions due to their high global-warming potential. Many treatment technologies have been developed, including the plasma, catalytic, and thermal destruction of waste HFCs. From an economic perspective, existing facilities should be capable of ensuring their destruction, without the addition of more energy or after-treatment systems. Here, a high-temperature thermal destruction method for HFC-134a from end-of-life vehicles (ELVs) is presented at the pilot and full operating scales. The method involves reductive conditions in a laboratory-scale reactor and a gasification melting system. The destruction removal efficiency (DRE) increased as the reaction temperature and the normal stoichiometric ratio (NSR) increased in a laboratory-scale reactor. HFC-134a was completely destroyed at 950 °C, a residence time of 4 s, and NSR of 1.0–2.0. The optimum NSR was found to be 1.5 for this system. Based on FT-IR and GC-MS analysis, a removal efficiency of more than 99.99% was obtained in pilot and full-scale systems. HFC-134a was completely destroyed at the feed rates of 0.15, 0.375, 0.75, and 1.5 kg/h in a pilot-scale system. The atmospheric emissions, including dioxin, were shown to satisfy regulatory levels for the pilot and full-scale systems. This suggests that gasification-melting system can be useful tools for decomposition of HFCs and has the potential to be a practical process for the treatment of wastes from ELVs including not only the automobile shredder residue and but also refrigerants.