Studies on the production of Tetrafluoroethylene by thermal decomposition of R-22 under the various reaction conditions

Abstract

Chlorodifluoromethane (CHClF2, R-22) is used as a refrigerant for automobiles, refrigerators, and air conditioners. The Montreal Protocol (1991) defined HCFC (Hydrochloro-fluoro-carbon) as a cause of ozone layer destruction and regulated the use of HCFC globally. The research of R-22 pyrolysis under the non-catalytic and catalytic conditions has been conducted to produce TFE. The R-22 pyrolysis reaction was carried out under the fixed bed reactor system at 550-800 °C, a residence time 0.1-1.14 sec, atmospheric pressure, and a steam/R-22 molar ratio of 4-10. It was found that TFE production by non-catalytic R-22 pyrolysis was showed higher performance than catalytic R-22 pyrolysis reaction under the superheated steam conditions. R-22 conversion was increased with increasing reaction temperature under the non-catalytic pyrolysis condition, and increased with increasing the ratio of steam to R-22. TFE selectivity was obtained more than 90% at the reaction temperature range between 600-700 oC, and dramatically decreased less than 600 oC and more than 800 oC, respectively.