جستجوی مقالات مرتبط با کلیدواژه « octane number » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

The Automotive exhaust emission is the predominant source of air pollution. With the increasingly stringent environmental protection requirements, the standards of gasoline are constantly upgrading via reducing the content of olefins, sulfur and aromatics. Alkylation of isobutane with butene is one of the most important ways for production of gasoline with high octane number. Although, the isobutane with olefins alkylation refinery process based on liquid acid catalysts such as sulfuric acid and hydrofluoric acid has been commercially successful but the use of these catalysts in the process of alkylation has environmental, health and high operatin costs problems. Solid acid catalysts especially zeolites due to their high operability and lower cost of equipment, no environmental problems and outstanding structural properties, are more suitable candidates for improving the isobutane/butene process. So, replacing these catalysts with solid acid catalysts is one of the most important research goals in the field of catalysts.

After recognizing the toxic and carcinogenic effects of Lead organic compounds, production of compounds such as Methyl tertiary butyl ether as an additive to ordinary hydro carbonate gases was proposed. These materials are able to enter into water, soil and air due to relative steam pressure and partial dissolution in water and cause the pollution. As a result, development of a new process for producing gas with high octane from complex compounds of light petroleum distillates was initiated. This method is based on separating C5-C8 linear and branched alkanes according to their absorption properties, chain length and the number of branches. In this study, the hybrid neural network model based on experimental data in the database has been used as an alternative model for predicting the separation rate of linear and branched paraffin through absorption process. Absorption temperature, absorption time, hydrocarbons' octane number, and hydrocarbon density are considered as four input parameters, and the ratio of linear paraffin concentration to total (C/C0) as the output parameter of neural network. The neural network model was successfully generalized by experimental database and then was investigated with the help of test data. The results of modeling for the test data indicated the success of neural network model in predicting the rate of linear paraffin separation from non-linear ones. Therefore, the developed neural network model can be used for determining the C/C0 with confidence in absorption process. According the obtained results for test data, the minimum mean squared error is 0/0518, which is a satisfactory measure. The model and experimental data were compared and regression coefficient 0.990 shows good matching between modeling results and experimental results.

The need to eliminate lead and decrease aromatic and olefin particles for the reason of biological problems it causes decline quality and quantity of gasoline production. So using alkylation as additive parts to gasoline can eliminate restrictions applied. The alkylation unit is designed that prevents side reaction as polymerization, while stop regarding the operation conditions such as reaction occurs and quality of alkylate will be reduced. In this article, first, will be explained the process of alkylation with sulphuric acid, then effective operation parameters with be illuminated, and the end limitation of this parameters are obtainable by this study in Abadan alkylation unit.

Improvement of fuel quality to decrease the impact of environmental and health effects are an important issue all around the world. Increase the octane number of light naphtha is one of the most important processes in modern refineries due to benzene limitation, aromatics, and olefins. Nowadays in refineries, the octane number of hydrocarbon blend is enhanced with components such as 2, 2-DMB, and isopentane. So the purpose of light naphtha isomerization process is the production of these isomers and increase it to hydrocarbon blend with low benzene and finally octane enhancement. In this review, different kinds of naphtha isomerization catalyst are investigated which is included chlorinated alumina, zeolite and sulfated zirconia.

Isomerization process is the most interesting method insofar as it converts straight chain paraffinic hydrocarbons with a low octane number to branched chains hydrocarbons with a higher octane number. In this process, light naphtha can be converted to gasoline. In this work, the importance of hydrocracking reactions has been investigated that occur along with other reactions such as isomerization, ring opening of naphthenic hydrocarbons, and saturation reactions. A reaction network has been developed which includes 15 lumps and 16 reactions. In the present study, a kinetic model was developed using a reaction network and the model was tested by the experimental data from a pilot plant using various operational conditions and industrial feeds with different qualities. There is good agreement between the product composition obtained by the kinetic model and the experimental data. The results of modeling indicated that the optimum reactor temperature could be affected by hydrocracking reactions. This temperature occurs before the acceleration of the hydrocracking reactions and the maximum octane number of the liquid product can be obtained at this optimum temperature. The results of the kinetic modeling demonstrated that the optimum temperature could be changed by the variation of hydrogen to feed ratio and liquid hourly space velocity.

The purpose of the catalytic reforming process is the production of high octane number gasoline which is a strategic and economic in the trade market. In this research, the regeneration of commercial Pt-Re/Al2O3 catalyst used for catalytic reforming of heavy naphtha is studied in the laboratory scale. This catalyst is unloaded from a fixed-bed reactor located in an Iranian refinery, and is at the end of its cycle life (about 2 years). After loading the catalyst in the laboratory scale, for performing the regeneration process, the coke on the surface of the catalyst is burned with the dry air. Then, chlorination process is carried out for the re-dispersion of chlorine agent on the catalyst surface. Finally, the catalyst is reduced and sulfided using hydrogen and H2S streams, respectively. During the regeneration, the flow rate, temperature and pressure of process are meticulously controlled, and also the optimized values are chosen to have the best regeneration. The results show that the regenerated catalyst, according to the recommended method in this research, has the capability of producing gasoline with the octane number higher than 100 which is approximately similar to the gasoline produced by the fresh commercial catalyst.

Nowadays, isomerization process plays an important role in producing valuable products in different industries. These reactions are limited by thermodynamic equilibrium and reaching beyond the equilibrium conversion and high selectivity in conventional reactors is not achievable. Therefore, using new technologies such as membrane reactors, for increasing the efficiency of this process is necessary. In this paper, isomerization of linear and cyclic hydrocarbons in membrane reactors was investigated and their performance was evaluated in comparison with conventional catalytic reactors which consist from zeolite membranes MFI and zoelite catalyst, according to the results presented in literature. The obtained results showed that in these reactors, membrane plays a vital role in increasing the reaction rate, selectivity, better controlling of the reaction, reducing in energy consumption and increasing the final efficiency of the reaction.