نشریه فناوری های نوین در سیستم های انرژی
سال دوم شماره 2 (پیاپی 202، تابستان 1395)

Thermal conductivity of Nano fluids is one of the most important properties in heat transfer processes. Many theoretical, analytical, and empirical correlations have been presented for estimating thermal conductivity of Nano fluids. In this study, 434 experimental data used in Al2O3-Water, Al2O3-EG, Al2O3-Water-EG, TiO2-Water, and TiO2-EG systems. Then, by employing these data, the ability of existing correlations for estimating thermal conductivities of Nano fluids were investigated. The results showed that the Patel et al. correlation (R2=0.94), and Minsta et al. correlation (R2=0.9) are the best equations. Finally by combining the two correlations, a new correlation was introduced. The new correlation showed the notable agreement with experimental results (R2=0.9718) in comparison with others.

Effect of Ce promoter on the catalytic performance of Ni/SBA-16 for partial oxidation of methane was investigated. Ni/SBA-16 Catalyst with ceria promoter were prepared by the impregnation method and employed in partial oxidation of methane (POM). The textural properties of prepared catalysts were characterized by N2 adsorption and XRD techniques. The catalytic performance of samples was evaluated in a micro reactor and conversion of CH4 in the temperature range of 700 to 850◦C was obtained. The obtained results showed that the methane conversion didn’t change with the addition of ceria at the ration of Ni/Ce of 1/1. However, the addition of Cu to Ni/SBA-16 resulted in the reduced methane conversion at the same ratio of Ni/Cu. Furthermore, comparison of methane conversion on the SBA-16 supported catalysts with the similar catalysts supported on SBA-15 published in the literature indicated superior performance of SBA-16 as a catalyst support in catalytic partial oxidation of methane.

Due to the significance of parking spaces, today, many populated centers such as universities, companies, and institutions dedicate private parking spots to their personnel. For this purpose, they assign security staff to the entrance of the parking lots to avoid unauthorized entries. In his paper, the researchers offer an efficient way for university parking management to control the traffic and regulate the car parks in a way that each student is obliged to use his/her own parking lot. In this system, after initial identity checks, each student is required to park in his/her spot under current traffic regulation, breaking which leads to sustaining traffic tickets.

In this paper, a mathematical model was developed to stimulate synthesis gas production by Methane steam reforming process in the presence of Nickel catalyst in a fixed bed reactor. For modeling of the reactor, first the physical principles were expressed, then simplifying assumptions were described in the form of mathematical expressions and a mathematical model was obtained using conservation of energy and mass conservation equations. Using the results of the model, the distribution of concentration, temperature and hydrogen yield were evaluated in the reactor and the effect of parameters such as temperature, pressure and steam to Methane ratio on reactor performance was evaluated. Finally, the model results were compared with experimental data.

The use of fossil fuels such as petrol play a crucial role in ever-increasing global warming due to its irreparable, destructive environmental effects and emission of greenhouse gases, and it is considered as a serious and major threat to the environment. The use of biofuels as environmental friendly substances for taking advantage into vehicles has been highly regarded. In this paper, density of three bio-fuels were calculated (from 40 to 140 Mpa) with various thermodynamic equations such as Redlich-Kowng and Peng-Robinson and taking into account of various mixing rules and a viral EOS which named BWR-LS. Due to the specific pressure (pressure of diesel engine injector) activity equations such as Wilson for the unavailability of required constants was not appropriate. The results of conducted calculated is presented that, BWR-LS and PR-MHV2 in general mode for considered substances with having under 3 percentage error is proper (Dibutyl ether+1-butanol, 1-heptanol+ heptane).

H2S and CO2 removal using alkanolamines is one of the most important processes which frequently used in industry. In this study, different amines were utilized for gas sweetening propose. Selecting appropriate amine directly effects minimization of energy consumption and expenses as well. Amine circulating rate and required energy for amine regeneration are the most important parameters for amine selection. In this regard, two types of amine with different concentrations were used. To reach desire separation, for this reason, DEA were used by of 25, 30, and 35 wt% concentrations, and DGA with 55, 60, and 65 wt% concentrations. Results showed that by increasing the concentrations of amine in amine solution, amine circulating rate and energy consumption were decreased. So, the best scenario is use of amines with highest possible concentrations. In addition, amine circulating rate was significantly decreased by replacing DGA in process. Thus, using 65 wt% DGA had the best results for gas sweetening process.