S. Prasad et al., A BOUNDARY-LAYER MODEL OF A PARALLEL-PLATE ELECTROCHEMICAL REACTOR FOR THE DESTRUCTION OF NITRATES AND NITRITES IN ALKALINE WASTE SOLUTIONS, Journal of the Electrochemical Society, 142(11), 1995, pp. 3815-3824
Electrochemical processes appear to be attractive for treating low lev
el nuclear wastes. The development of a simple divided electrochemical
-cell model operating in a batch mode, used for the reduction of nitra
tes and nitrites from nuclear wastes, is presented. This model, based
on a boundary-layer approach, is simple and yet encompasses the key fe
atures of a previously developed distributed-parameter model that incl
udes diffusion, migration, and convection as the flux components. Beca
use it dramatically reduces computation time, this boundary-layer mode
l is well suited for use in a complex interactive flowsheet model and
for optimization studies. The boundary-layer model is used to predict
partial current densities, reservoir concentrations, and off-gas compo
sitions as a function of time.,Good agreement between simulated and ex
perimental data (i.e., nitrate and nitrite concentrations and off-gas
compositions) is observed over the course of a batch run. In addition,
a comparison with a rigorous distributed-parameter model is made to i
llustrate the accuracy and robustness of this model. The results of se
lected case studies are shown, and a preliminary batch optimization is
carried out to show how the model can be used to maximize the destruc
tion of nitrates and nitrites.