Modeling and simulation of the vaporization of LuCl3 in Ar and N2

M.R. ESQUIVEL; M.O. BARBAGLIA

Ciudad de Mar del Plata-Pcia de Buenos Aires

Congreso; Jornadas SAM/CONAMET/MEMAT 2005; 2005

Universidad de Mar del Plata

The technological transference of data of the vaporization of lanthanide chlorides from laboratory to industrial scale is difficult because both of the many complications related to handling them in systems depleted of water and oxygen and the lack of data of transport properties such as the diffusion coefficients. Nevertheless, the vaporization process of these chlorides can be simulated if the fluid dynamics of the system is known and the diffusion coefficients are estimated from compounds similar to these chlorides. In this work, the vaporization of LuCl3 in Ar (g)and N2(g) is studied using an horizontal cylindrical chemical reactor containing a crucible in the shape of a parallelepiped. The analysis is done for gas inlet linear velocities of 4.42.10-2, 4.42.10-3 and 4.42.10-4 m s-1 for temperatures between 600 and 950 ¨¬C for mass samples of 0.2 , 20 and 200 mg. The diffusion coefficients are estimated from the ones of LaCl3(g)-N2(g) and LaCl3(g)-Ar(g) obtained in a previous work. The process is studied assuming external mass transfer is the controlling process. This step was modeled by using a previously developed expression of the mass transfer coefficient where three stages in series are considered. Using the formulism of the equations of Slatery and Bird and Blanc, the binary diffusion coefficients of LuCl3(g)-Ar(g) and LuCl3(g)-N2(g) were calculated. From the simulations, the following equation representing the process was obtained: A.T.R).Re664,0)1(1(g3/12/1323033103esgsSpeciesLaClSpeciesLuClSpeciesLuClLuClLuClPPScDlDlDlN−++−=−−−¥á (1)3 in Ar (g)and N2(g) is studied using an horizontal cylindrical chemical reactor containing a crucible in the shape of a parallelepiped. The analysis is done for gas inlet linear velocities of 4.42.10-2, 4.42.10-3 and 4.42.10-4 m s-1 for temperatures between 600 and 950 ¨¬C for mass samples of 0.2 , 20 and 200 mg. The diffusion coefficients are estimated from the ones of LaCl3(g)-N2(g) and LaCl3(g)-Ar(g) obtained in a previous work. The process is studied assuming external mass transfer is the controlling process. This step was modeled by using a previously developed expression of the mass transfer coefficient where three stages in series are considered. Using the formulism of the equations of Slatery and Bird and Blanc, the binary diffusion coefficients of LuCl3(g)-Ar(g) and LuCl3(g)-N2(g) were calculated. From the simulations, the following equation representing the process was obtained: A.T.R).Re664,0)1(1(g3/12/1323033103esgsSpeciesLaClSpeciesLuClSpeciesLuClLuClLuClPPScDlDlDlN−++−=−−−¥á (1)3(g)-Ar(g) and LuCl3(g)-N2(g) were calculated. From the simulations, the following equation representing the process was obtained: A.T.R).Re664,0)1(1(g3/12/1323033103esgsSpeciesLaClSpeciesLuClSpeciesLuClLuClLuClPPScDlDlDlN−++−=−−−¥á (1)A.T.R).Re664,0)1(1(g3/12/1323033103esgsSpeciesLaClSpeciesLuClSpeciesLuClLuClLuClPPScDlDlDlN−++−=−−−¥á (1) In this equation, DLucl3-Species , l0, l1,l2 are the binary diffusion coefficient of LuCl3 in either N2(g) or Ar(g), the boundary layer closer to the surface of the chloride thickness, the thickness of the layer defined within the crucible and the thickness of the gas layer between the top of the crucible and the gas bulk. Re and Sc are the numbers of Reynolds and Schmidt. Ps and Psg are the vapor pressure of the chloride in the surface of the sample and the bulk gas. Ae, Rg and T are the area of mass transference, the gas constant and absolute temperature, respectively. ¥áLuCl3 is the vaporization degree of LuCl3. From this expression, the vaporization evolution with time is simulated using T, ¥áLuCl3 and linear velocity as parameters of operation. These results are aimed to facilitate the scaling up of a chemical reactor oriented to study the kinetics of processes controlled by mass transfer .Lucl3-Species , l0, l1,l2 are the binary diffusion coefficient of LuCl3 in either N2(g) or Ar(g), the boundary layer closer to the surface of the chloride thickness, the thickness of the layer defined within the crucible and the thickness of the gas layer between the top of the crucible and the gas bulk. Re and Sc are the numbers of Reynolds and Schmidt. Ps and Psg are the vapor pressure of the chloride in the surface of the sample and the bulk gas. Ae, Rg and T are the area of mass transference, the gas constant and absolute temperature, respectively. ¥áLuCl3 is the vaporization degree of LuCl3. From this expression, the vaporization evolution with time is simulated using T, ¥áLuCl3 and linear velocity as parameters of operation. These results are aimed to facilitate the scaling up of a chemical reactor oriented to study the kinetics of processes controlled by mass transfer .¥áLuCl3 and linear velocity as parameters of operation. These results are aimed to facilitate the scaling up of a chemical reactor oriented to study the kinetics of processes controlled by mass transfer .