Modeling of the chemical behavior of sodium fire aerosols during atmospheric dispersion

Abstract

The use of liquid sodium as a coolant in sodium-cooled fast reactors (SFR) circuits requires studying the consequences of a sodium fire for safety analysis, and particularly the toxicological impact of sodium fire aerosols. More particularly, the carbonation of sodium fire aerosols from sodium hydroxide (NaOH) to sodium carbonate (Na 2 CO 3) is investigated. A new kinetic model, based on the CO 2 reactive absorption and the two-film theory, is developed to describe the carbonation process of NaOH solutions, taking into account the NaOH aerosols' initial characteristics in equilibrium with the atmosphere. This model is applied for the case of NaOH aerosols considering the CO 2 absorption at the particle external surface. The estimation for the model parameters is detailed as function of NaOH degree of conversion, relative humidity (RH), and temperature. By comparisons with available experimental data, the absorption interfacial area is empirically estimated over the studied range of RH and initial particle diameter. The global sensitivity study of the model confirms its capabilities to describe NaOH aerosols' carbonation, waiting for new experimental data for validation.

Hydrodynamics and Mass Transfer Characteristics for Extractive Desulfurization of Diesel Using Highly Viscous Ionic Liquids in Microchannels: The Effect of the Phase Ratio and Temperature

“…To gain a deep understanding on the mass transfer characteristics of the IL-EDS process, the two-film model, commonly used for modeling extraction in microreactor systems, was chosen to describe our system. In the two-film model, the mass transfer coefficient of inside and outside a droplet can be calculated as ,, where δ d (m) and δ c (m) are the thicknesses of the hypothetical films adjacent to the interface in the IL phase and the MD phase, respectively. D d (m 2 /s) and D c (m 2 /s) are the diffusion coefficients of DBT in the bulk IL and MD phases, respectively.…”

“…D d (m 2 /s) and D c (m 2 /s) are the diffusion coefficients of DBT in the bulk IL and MD phases, respectively. Then, the overall mass transfer coefficient ( K ) can be predicted as ,, …”

Recyclable carbon nanotube/silicone oil emulsion with NaOH aqueous solution for indoor CO2 capture

“…The NaOH aqueous solution that constituted the droplet reacted with CO 2 and caused crystallization at the interface; because there was no flow and no circulation inside the fluid, the thickness of the material diffusion boundary layer increased. 26 The size of the emulsion droplets formed in ES–NaOH was measured using DLS. The size of the droplets was in microscale and similar to that in the study of Pickering emulsions based on CNTs (Fig.…”

“…Because the CO 2 capture reaction occurs at this interface, crystallization occurs here, and if solidification proceeds, the absorption of CO 2 is hindered. 26 Therefore, in the process of using NaOH as an absorbent, it takes the form of fine droplets that are sprayed using a sprayer 27 or a membrane contactor. 28 To safely and effectively use these chemical absorbents indoors, they must be fixed in an effective form like a solid adsorbent so that they do not flow, scatter, or get affected by crystallization.…”