Plasma Enhancement Gas (PEG), namely inert gases (nitrogen, neon, argon, etc.), are used in order to mitigate the heat load over plasma facing components. In particular, PEG separation is part of the Plasma Exhaust Processing System of DEMO. Previous studies have been dedicated to study the PEG separation via ceramic porous membranes by modeling the mass transfer mechanisms and performing preliminary tests with pure gases. This manuscript reports the results of gas permeability tests carried out on two commercial ceramic porous membranes with binary mixtures of H2 with Ar, N2, He, and DT. The experiments have been carried out at room temperature and feed pressure 105–150 kPa by collecting the permeate stream at atmospheric pressure. Since preliminary binary tests have shown that the experimental apparatus adopted was not capable to realize any detectable gas separation between the permeate and retentate streams, two following tests with the retentate valve closed have been carried out. In the first test only hydrogen was fed through the membrane, while in the second test a mixture of hydrogen and a PEG gas was sent to the membrane. The flow rate of PEG gas needed to achieve the same pressure drop adopted in the test with only hydrogen has been used to assess the gas selectivity. The equation used to calculate selectivity values is valid only when both: pressure drop across the membrane is equal for both tests and composition of gas mixture on both side of the membrane is assumed to be equal for the second test. Experiments with binary mixtures exhibited selectivity values lower than those assessed theoretically in previous works where single gases have been tested. Through the values of measured selectivity, a new preliminary design of a membrane system consisting of a cascade of ceramic porous membranes followed by a Pd-permeator has been carried out.
|Titolo:||Testing of ceramic porous membranes for separation of binary mixtures of Plasma Enhancement Gases|
|Data di pubblicazione:||2020|
|Appare nelle tipologie:||1.1 Articolo in rivista|