Noureddine Ouerfelli has a PhD and Habilitation Diploma in Chemistry; he is a head of research project in the Laboratory of Biophysics and Medical technologies. He has published more than 45 papers in reputed journals on modeling of Physicochemical properties in solution
Knowledge and estimation of transport properties of fluids are necessary for mass flow and heat transfer. Viscosity is one of the main properties which are sensitive to temperature and pressure variation. In the present work, based on the use of statistical techniques for regression analysis and correlation tests, we propose an original equation modeling the relationship between the two parameters of viscosity Arrhenius-type equation (ln = lnAs + Ea/RT). Empirical validation using 70 data set of fluids provided from the literature and studied at different temperature ranges gives excellent statistical results which allow us to redefine the Arrhenius-type equation using a single parameter instead of two ones ( ). More, causal correlation between these parameters and the normal boiling temperature (Tb) of the corresponding fluids leads us to propose two predictive empirical equations one with the activation energy ( ) and one with the logarithm of pre-exponential factor ( ). We conclude that the boiling temperature is in causal correlation with the two Arrhenius parameters, but with other physical and chemical properties implicitly for which there are some ones are common for the two Arrhenius parameters while others are in relationship only for a single parameter (lnAs) or (Ea). To correct this observation, we will try to suggest in future works, an expression both explicit, the two viscosity Arrhenius parameters Tb(Ea,lnAs) alternatively in the numerator and in the denominator. Note that this equation is tested to some heavy oils with reliable agreement for which we can conclude that it can be useful for petroleum chemistry.
KHIR Tahar is Professor in Mechanical Engineering at National Engineering School of Gabes – Tunisia. He was Adviser of the Minister of Higher Education and Scientific Research from 2012 to 2014. He received his BSc in Mechanical Engineering from the University of Tunis (1983). He obtained his MSc Degree in Energetic from the University of Paris XII (1984). He was awarded his PhD from the same University in Energetic Systems and Energy Management (1987). He Obtained his Habilitation Degree in Energy System from the University of Gabes (2011). His research works cover Industrial refrigeration, Thermo-economic optimization, Power Plants and Renewable Energies.
Energetic and exergetic analysis is performed on a Steam Turbine Power Plant used in a Phosphoric Acid Factory. The power plant is mainly constituted by two steam turbine cycles STGI, STGII and a turbo-blower group Tb-Bl. rnMass, energy and exergy balances are established on the main compounds of the plant. A numerical code is established using EES software to perform the calculations required for the analysis considering real variation ranges of the operating parameters such as pressure, temperature and mass flow rate. The effects of theses parameters on the system performances are investigated.rnThe minimum irreversibility rates are obtained for the condensers (0.5 MW), the deaerators (0.4 MW) and the blower (1.5 MW) followed by the pumps and steam turbines. The heat exchangers present an irreversibility rate of about 5 MW. The maximum energy efficiency is obtained for the blower followed by the heat exchangers, the deaerator and STGII. The exergy efficiency obtained for the heat exchanger, the steam turbine generator, the deaerator and the blower are 88 %, 74 %, 72 % and 66 % respectively. The exergy effeciency of STGI is analyzed taking into account the condensate flow rate. For mass flow rates through the condenser of 12, 18 and 20 t/h. The optimum HP steam flow rates feeding the turbine, leading to the maximum exergetic effeciency are 49, 51 and 56 t/h respectively. rnFor the back pressure steam turbine STGII a maximum exergetic efficiency of about 75.5 % is obtained with of 73 t/h.rn