DAMIAN AXENTE, ANCUTA BALLA, STEFAN BUGEAC, MIHAI GLIGAN, CRISTINA MARCU THE CALCULUS OF THE OPERATION PARAMETERS AT PRESSURE OF THE PRIMARY SEPARATION COLUMN OF THE 15N PRODUCTION PLANT The relations for calculus of: 10M HNO3 solution flow, isotopic transport, 15N molar fraction at the bottom of the separation column, product flow, interphasic transfer velocity, height equivalent to the theoretical plate and sulfur dioxide flows in both stages of the product refluxer are presented for 15N separation column with different diameters and 10M HNO3 feeding flow rates, operated at pressure up to 1.5 atm. In order to produce the isotope 15N at 99 at. % 15N by isotopic exchange in Nitrox system it is desirable to operate the production plant at biggest flow of 10M HNO3 solution, which allows the 15N production at that concentration on a given plant. That will be possible by operating the plant at pressure as it is shown in this work. At 0.8 atm pressure (1.8 atm absolute) the isotopic separation at higher flow rates would be practically equal with that obtained at lower flow rates and atmospheric pressure. For constant: HETP = 10.85 cm, 15N molar fraction of the feeding 10M HNO3, Nf = 0.00365, and of the product, Np = 0.12, the variation of the primary separation column product and of the 15N production plant, as a function of the feeding flow with 10M HNO3 solution, are also presented.
Keywords: 15N production, Nitrox system, operation parameters at pressure