جستجوی مقالات مرتبط با کلیدواژه « سنتز فیشر تروپش » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

Heat transfer has a crucial importance in the engineering applications; therefore, various methods for enhancing the heat transfer have been proposed by the researchers and new methods have been developed in recent years. One of these methods is using nanofluids. Nanofluids have enhanced thermal properties in compare with the base fluid. In this paper, the latest studies on the use of nanofluids in the double tube heat exchangers and shell and tube heat exchangers with description of the test system has been evaluated and the results have been summarized.
In the end, the results of using shell and tube heat exchangers as a bed for exothermic reactions in the process of Fischer-Tropsch synthesis using nanofluids is provided. In all of the work done by increasing the nanoparticles volume fraction and the Reynolds number, the heat transfer coefficient and process efficiency have increased.

In this work a computational fluid dynamic (CFD) and experimental study of Fischer–Tropsch Synthesis (FTS) process in a fixed-bed reactor is presented. The reactor was a 1.2 cm diameter and 80 cm length steel tube in which ceramic particles were employed to dilute the catalyst bed and thus prevent the emergence of hot spots in it. An axi-symmetric CFD model with an optimized mesh of 22016 square cells was developed to model hydrodynamics, chemical reaction and heat and mass transfer in the reactor. Non-ideal thermodynamic behavior of gas mixture was modeled using Peng-Rabinson equation of state. Kinetic models for FTS and Water–Gas-Shift (WGS) reaction rates based on Langmuir–Hinshelwood type for each of species were employed. Good agreement was achieved between bench experimental data and the model. Because of the high price of reaction experiments and also safety the validated model used as numerical setup and the CFD simulations considered as numerical experiments. A sensitivity analysis was carried out in order to find the effect of temperature, pressure, and GHSV and H2/CO ratio on the reactor performance.

Fischer Tropsch Synthesis is a reaction that takes place between carbon monoxide and hydrogen (syngas) based on heterogeneous catalyst. Products of the reaction include a mixture of hydrocarbons and oxygenates, comprising mainly of paraffin, olefin and alcohol. This process produces high quality hydrocarbon fuels and hence its development can alleviate many problems relating to transportation industry pollution. The most recent investigation of references reveals that from the mechanistic viewpoint, Anderson Schulz-Flory distribution model can determine the trend of hydrocarbon formation. Fluidized bed, fixed bed and slurry phase reactors are the three common types of reactors in the process; however, only the last two reactors have industrial usage. Metals from the VIIIB group of the periodic table such as iron, cobalt and ruthenium are used as process catalysts. However, only iron and cobalt have been accepted for industrial application.

Mechanical strength is one of the technical properties of heterogeneous catalysts which strongly depends on their synthesis and forming method. A serious problem with the use of Fe Fischer-Tropsch catalysts in a reactor is their tendency to undergo attrition. In this paper the factors affecting the extent of attrition of catalysts and specialy Fe Fischer-Tropsch catalysts in slurry reactors are initially introduced. The effect of spray drying along with silica binder on improvement of attrition resistance of co-precipitated Fe Ctalysts are presented afterward. It is shown that by spray drying method, under optimum operational conditions, production of spherical catalyst's granules with suitable density and strength is possible. Furthermore, strength of the granules would be enhanced using proper amount of silica binder.