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Hydrofluorocarbon (HFC) working fluid with high global warming potential are step out of the stage of history due to the intensifying global greenhouse effect. Supercritical water gasification (SCWG), an effective and clean waste disposal method, may have better potential for the conversion of waste HFCs working fluid. ReaxFF reactive molecular dynamic and density functional theory method are used in this work to investigate the SCWG mechanism of HFC-245fa. The results indicate that the main products of HFC-245fa SCWG are high value-added chemicals and fuels such as CO, CO 2 , H 2 , and HF. During the gasification process, almost 100 % of the F atoms in HFC-245fa have the potential to become HF, which means that the SCWG method has a strong defluorination effect. The generation of H 2 molecules is promoted and the formation of CO molecule is inhibited in the presence of H 2 O molecules. More importantly, hydrogen bonds are formed between HFC-245fa and H 2 O molecules, which results in the dissociation of HFC-245fa is improved by the SCWG environment. This work provides an available and environmentally friendly route for the efficient conversion of waste HFCs to fuels. [Display omitted] • Supercritical water gasification method has a better defluorination effect. • Almost 100 % of the F atoms in HFC-245fa have the potential to become HF. • Hydrogen bonds promote the decomposition of HFC-245fa and H 2 O molecules. • HF, H 2 and CO rich products could be selectively produced. [ABSTRACT FROM AUTHOR]

Pyrolysis is one of the potential way for the degradation of hydrofluorocarbons, but it is difficult to make effective use of the complex pyrolysis products. The addition of plastics can provide sufficient hydrogen source for the degradation of hydrofluorocarbons to generate the high value-added chemicals and fuels. Density functional theory calculation and reactive molecular dynamic simulation are employed to investigate the co-pyrolysis mechanism of 1,1,1,2-tetrafluoroethane and low-density polyethylene in this work. The results show that the H atoms provided by low-density polyethylene promote the defluorination reactions of 1,1,1,2-tetrafluoroethane to generate HF and short chain hydrocarbons, and the number of F atoms in HF molecules accounted for nearly 80 % of the whole reaction system, achieving a better defluorination effect. The defluorination rate of 1,1,1,2-tetrafluoroethane and plastics co-pyrolysis is more than 5 times that of pure 1,1,1,2-tetrafluoroethane pyrolysis. The main co-pyrolysis products of 1,1,1,2-tetrafluoroethane and low-density polyethylene are H 2 , HF and short chain hydrocarbons, the purpose of hydrofluorocarbons degradation into high value-added chemicals and fuels is realized in this study. This work provides a green, effective way for the conversion waste hydrofluorocarbons and waste plastics into high value-added chemicals and fuels, and achieves the conversion of waste hydrofluorocarbon refrigerants to more economical products. • Co-pyrolysis mechanism of hydrofluorocarbons and plastic is first time studied. • Co-pyrolysis process of 1,1,1,2-tetrafluoroethane and low-density polyethylene is described. • Plastic as a hydrogen donor promotes the defluorination of 1,1,1,2-tetrafluoroethane. • HF, H 2 and short chain hydrocarbons rich products could be selectively obtained. • Pyrolysis products of waste hydrofluorocarbons can be enhanced by adding plastics. [ABSTRACT FROM AUTHOR]