A. Viola

Tritium recovery from liquid Li17Pb83 alloy blanket material

Abstract Two methods to recover the tritium from the Li 17 Pb 83 liquid breeder used in the breeding blanket design developed at JRC-Ispra for INTOR/NET [1] are outlined and discussed. They are (i) direct tritium pumping from stagnant and stirred breeder, and (ii) tritium extraction from a packed or bubble column by flushing an inert gas in counter-current to the breeder. The lack of experimental data on tritium solubility and diffusion and on other physico-chemical properties of Li 17 Pb 83 do not yet enable us to choose among the two schemes. However, at present the second appears more promising.

Mathematical model applied to permeation problems of process designs for tritium recovery from liquid blankets

A mathematical model has been developed to determine the amount of tritium that permeates the cooling circuit of a tritium breeding blanket containing the liquid eutectic alloy 17Li-83Pb. This model, which has been applied to phase 2A of the International Tokamak Reactor/Next European Torus project, is used to predict the effect of the operating conditions of the blanket, as well as those of a spray tower employed as a tritium recovery unit, and the kinetic parameters for the permeation and desorption processes. The results of this theoretical study indicate that the amount of permeated tritium proved to be not very different for the maximum (10.82 kPa/sup 1/2/ . m/sup 3/(mol . T)/sup -1/) and minimum (0.7 kPa/sup 1/2/ . m/sup 3/(mol . T)/sup -1/) values of Sieverts constant (K/sub s/) existing in literature. This amount, moreover, can be reduced to 0.1 to 0.01 g/day of tritium by the presence of small oxide barriers (a permeation reduction factor of ..cap alpha..approx. =100) on the cooling tubes and by the easy operating conditions of the spray tower, which include a droplet diameter of 0.5 mm; a tritium pressure of 0.13 kPa at 673K; and a residence time of 0.5 s.

Lumped kinetic model for propene—butene mixtures oligomerization on a supported phosphoric acid catalyst

Abstract A lumped kinetic model for the oligomerization of propene—butene mixtures on a supported phosphoric acid catalyst was developed. The model was based on four lumping criteria, stemming from the chemical properties of the reacting system. An automatic procedure for the self-dimensioning of the model, in terms of the number of considered lumped reactions, was derived. Finally, the model reliability was tested by comparison with experimental data, reported in the literature.

Two-step adsorption models in molecular sieves

Starting from analysis of the behaviour of peak retention time vs. the adsorption constant and vs. the mass transfer coefficient, we propose a simple macroscopic model describing adsorption in molecular sieves at high Peclet numbers and at low temperatures. The model is based on the hypothesis that adsorption kinetics evolve through the superposition of an instantaneous adsorption step and a slower step controlled by mass transfer resistance. A detailed moment analysis is performed by comparing the results of the two-step model with those deriving from classical adsorption models (linear driving force model and macropore-micropore model) and with experimental chromatographic data of H2-D2 adsorption on NaCa-Mordenite. The experimental results at low temperatures validate the proposed model.

Size Effects, Thermodynamic Consistency and Non-Ideal Energetic Behavior of Adsorption Isotherms in Microporous Materials

One of the fundamental problems in gas-solid adsorption on heterogeneous surfaces and microporous materials is the formulation of thermodynamically consistent models for single-component and multicomponent adsorption equilibria encompassing the influence of geometric and energetic heterogeneity.