Mahmoud Gorji - Assistant Professor of Chcmicai Engineering, Malek Ashlar University of Technology

The present research was concerned with improvement of liquid phase hydrogenation reliction of NDMA from mass transfer view point. Empirical studies in liquid phase hydrogenation of Nitrosodimclhylaminc (NOMA) to Unsymmetrical dimethyl hydrazine (UOMH) carried out in semi-batch stirred lank reactor , indicated that the gas-liquid phase mass transfer will be the ralecontrolling step of the overall reaction rate if inadequate gas-liquid mixing occurs_ To increase the reaction rate in this case, one may increase hydrogen equi librium constant by changing the operating conditions. On thc othcr hand, hydrodynamics of liquid and gas phascs, as well as, masstransfcr bctween these two phascs is a complcx funct ion of opcrating conditions. Computational Fluid Dynamics (CFO) is a nsellLl tool to investigate gas-liquid mass transfer. However, most simulations to date reported in the literature consider only the hydrodynamics of a given systemIn this work, a two dimcnsional cro model is uscd to invcstigatc effects of thc mass transfcr in thc improvemcnt of the rcactor performancc. For this purpose two flu id (Eulerian-Eulerian) model and fin itc volumc method, along with standard k - & model to addrcss turbulent behavior of both phase, have been nsed. Resnlts of mass transfcr mn showed that hydrogen concentration in liquid watcr is increascd progrcssively until rcaching its cquilibrium value. Furthennorc, it is seen thatthe Henry's law constant alTects the mass transfer mn time needed to reach its equilibrium value

NOMA, hydrogcnation, gas-liquid, mass transfcr, CFO