A study on the kinetics of bismuth oxide reduction by hydrogen as applied to the technology of removing hydrogen from circulation circuits with heavy liquid metal coolants

Abstract

As part of the project on developing methods for removing hydrogen and tritium from the circulation circuits of reactor plants with heavy liquid metal coolants, the authors studied the kinetics of bismuth oxide reduction by hydrogen in the temperature range of 425–500 °C and hydrogen concentrations of 25–100 vol.%. The kinetic characteristics of the test reaction were determined by continuous measurements of the water steam (reaction product) concentration in mixtures of hydrogen with helium that passed through a heated reaction vessel with a sample of bismuth oxide. The water steam concentration was measured by a thermal-conductivity detector. The obtained time dependences of the bismuth oxide reduction degree (with varying reaction conditions) were processed by the affine time transformation method. It was also found that the reduction process ran in kinetic mode. The reduction mechanism is the same in the entire temperature range. The limiting reaction stage is the adsorption of hydrogen on the surface of the bismuth oxide sample. The time dependence of the reduction degree is in good agreement with Avrami-Erofeev equation with n = 1. The reaction activation energy is 92.8 ± 1.9 kJ/mol. The reduction reaction rate is directly proportional to the concentration of hydrogen in its mixture with an inert gas.

Controllable Carbon Felt Etching by Binary Nickel Bismuth Cluster for Vanadium–Manganese Redox Flow Batteries

“…In the Ni 2p spectrum of NB-ECF, typical Ni 2p 3/2 and Ni 2p 1/2 peaks were obtained and were separated into five components. 58 The Ni 2p 3/2 peak consisted of a main peak (Ni 2+ ) at 850.3 eV, a shoulder peak at 852.1 eV (Ni 3+ ), and a satellite peak at 857.8 eV. The Ni 2p 1/2 peak was divided into a main peak (Ni 2+ ) at 873.1 eV and a satellite peak at 880 eV.…”

“…Especially, the intensity of the Ni 3+ peaks, which favors enhancing the surface area and forming active sites, was observed to be high in NB-ECF. 58 We also carefully explored the Bi 4f spectrum, and it contained two pairs of Bi peaks. First, a pair of peaks exhibited at 157 and 162.4 eV coincided with the Bi 0 peak, which meant that Bi 2 O 3 had been completely reduced to metallic bismuth by carbon.…”

“…The Ni 2p and Bi 4f spectra are shown in Figure d,e, respectively. In the Ni 2p spectrum of NB-ECF, typical Ni 2p 3/2 and Ni 2p 1/2 peaks were obtained and were separated into five components . The Ni 2p 3/2 peak consisted of a main peak (Ni 2+ ) at 850.3 eV, a shoulder peak at 852.1 eV (Ni 3+ ), and a satellite peak at 857.8 eV.…”

“…The Ni 2p 1/2 peak was divided into a main peak (Ni 2+ ) at 873.1 eV and a satellite peak at 880 eV. Especially, the intensity of the Ni 3+ peaks, which favors enhancing the surface area and forming active sites, was observed to be high in NB-ECF . We also carefully explored the Bi 4f spectrum, and it contained two pairs of Bi peaks.…”