Experiments and Modeling Studies of Hydrogen Isotope Separation by the Thermal Cycling Absorption Process under Nonconstant Feeding Rate Conditions

Abstract

The separation of hydrogen isotopes is a critical task in nuclear fusion fuel cycles, and the Thermal Cycling Absorption Process (TCAP) has proven to be an effective semicontinuous displacement chromatographic process based on the temperature-dependent isotopic effect of hydrogen absorption in palladium. In this study, much attention has been focused on hydrogen isotope separation by the TCAP under nonconstant feeding rate conditions. A dynamic separation column model including mass and energy conservation equations and the kinetics of hydrogen absorption/desorption was developed. The nonconstant feeding flow rates were fitted based on the measured experimental data of pressure. The proposed model was confirmed by the comparison of the simulated results with experimental data in terms of temperature, pressure, and D2 abundance under different feeding conditions. Finally, the validated model was employed to investigate the effect of feeding position, feeding temperature, feeding flow rate, and initial feed abundance of D2. The simulation results demonstrate that the farther the feeding position is from the product side, the higher D2 enrichment is observed. The optimized feeding temperature is 30 °C. The enrichment performance of the nonconstant feeding mode is superior to that of the constant feeding mode. The enrichment degree of D2 exhibits a monotonic relationship with feeding flow rate and initial feed abundance of D2. The proposed model is effective and can be employed to guide the optimization design of the TCAP.