Feasibility of regenerative adsorption of a hydrofluorocarbon (HFC-134a) using activated carbon fiber studied by the gaseous flow method

The adsorption and desorption behavior of the refrigerant HFC-134a on pitch-based activated carbon fibers (ACFs) with various Brunauer–Emmett–Teller surface areas was investigated by the flow method. Fixed-bed adsorption experiments performed at 20, 5, –15, –20, and −25 °C showed that the use of lower temperatures resulted in an increase in the adsorption capacity of the ACF. In particular, the complete adsorption time was dramatically increased at −25 °C. Crucially, even after five cycles of adsorption at –20 °C and desorption at 30 °C of HFC-134a in a electrothermal swing adsorption apparatus, significant decreases in the adsorption capability were not observed. The desorption of HFC-134a from saturated ACF was carried out using electric power directly applied to the ACF itself. The electric heating increased the ACF temperature, causing desorption within several minutes. The results of this study show that the regenerative adsorption of HFC-134a by ACF coupled with electric power is possible.