نشریه فناوری های نوین در سیستم های انرژی
سال دوم شماره 4 (پیاپی 204، زمستان 1395)

Undoubtedly, dew point pressure is a key parameter for determination of gas condensate phase diagram. Dew point prediction is a crucial issue for obtaining accurate performance of gas condensate reservoir. In this study, three empirical correlations are evaluated. These correlations are function of hydrocarbon components and non-hydrocarbon components, plus fraction and reservoir temperature. Next, the new hybrid correlation is developed as function Elsharkawy and Shokir correlations using 131 experimental data extracted from open literature. The results of new predicting correlation showed 11% improvement with respect to the best applied correlation Shokir.

Biosorption of several heavy metals including that zinc, cadmium, mercury and copper on Entromorpha as green alga was investigated. The Henry single parameter isotherm model and also both the Langmuir and the Freundlich as two parameters isotherms have been studied in the constant conditions with respect to the presence of operating parameters such as initial biomass dosage, temperature, initial pH, initial metal ion concentration and contact time. The results from atomic absorption measurements shown that the Freundlich isotherm model are more promise than the Henry and the Langmuir isotherm for Biosorption of zinc, cadmium, mercury and copper on Entromorpha. Therefore, we are encountered with heterogeneous, reversible and multilayers biosorption.

In this paper, the problem of using Graphene Nanofluids in high flux volumetric solar receiver is considered. In volumetric high flux receivers, because of high operating temperature and related heat loss to ambient, the overall performance is very small. Thus, using classic working fluids, these types of receivers will not compete with fossil fuel power plants. For this reason, the effect of using Graphene Nanofluids on the efficiency of the volumetric receiver is analyzed. For this purpose, the energy balance equations system are formulated for the volumetric receiver and then thermal radiation equations are applied to governed equations. In this modeling, the heat dissipation is neglected and total heat generation is applied to governed equation as a source term. For the numerical solution of governing equations, the explicit method is used. Comparisons of current numerical simulation with other experimental results show that considered modeling has an excellent agreement with experimental results. For evaluation of change in geometrical and radiation parameters on the thermal performance of the volumetric receiver, effect of optical thickness, receiver height, and solar concentration are evaluated. Evaluation of the volumetric high flux receiver with Graphene Nanofluids shows excellent improvement in the performance of the solar volumetric receiver. Finally, for analytical evaluation of numerical simulation, the results of numerical simulation at various heights and solar concentration apply to genetic programming tool and then the analytical expression for optimum optical thickness and optimum thermal efficiency are presented.