Abstract Natural gas has become an important source of energy in the world. Throughout the 19th century, natural gas was used almost exclusively as a source of light and its use remained localized because of lack of transport structures, making it difficult to transport large quantities of natural gas long distances. There was an important change in 1890 with the invention of leak-proof pipeline couplings, but transportation of natural gas to long distance customers did not become practical until the 1920s as a result of technological advances in pipelines. Moreover, it was only after World War II that the use of natural gas grew rapidly because of the development of pipeline networks and storage systems. Gas pipe lines are operated under steady state conditions. However, when transporting high temperature wet gas the gas getting cooled and heavy components condensate, Hence, pigs is usually are wanted to clean the pipe line to reduce pressure drop along the pipe In this study an existing pipeline was studied under steady and unsteady state. HYSYS and ProFES programs were utilized. Result show that gas temperature changes with time and distance. Results show that temperature and gas approach the ambient temperature at about 20 Km of pipe line length consequently, liquid phase volume fraction increase in first 20 Km of the pipe.
عدلي عمر احمد (2011)

Abstract 1. The experimental viscosities densities measured with Anton Paar SVM 3000 equipment, and refractive indices measured with Refractive Meter equipment, corresponding values of excess molar volumes (VE ), deviations in viscosity (Δμ), deviations in refractive index (ΔnD), excess Gibbs energy (GE), and excess molar enthalpy (HE), for binary, ternary and fourth mixtures of alcohol, ether, and n-alkanes. 2.Used for the calibration experimental from paper [7] were the mixture for the binary system (tert butyl alcohol + ethanol ), we had good result and ADD% for densities, viscosities and refractive indices were 0.1657 %, 0.4846 %, and 0.033545 % respectively. 3.Data of binary mixture were fitted to a Redlich-Kister's The choice of the proper number of coefficients (p), was based on the standard deviations, and the F-test as criterion of goodness with an error lower that 1% see. 4.Data of ternary and fourth mixture were correlated by Cibulka equation were determined with the optimization algorithm similar to that for the binary parameters the σ values was less than 0.05%. 5.The experimental viscosities densities and refractive indices were positive and decrease with increase temperature for all tables for binary ternary and fourth mixtures. 6.Excess molar volumes (VE), was negative value for all binary system, Deviations in viscosity (∆µ), negative value, but at system (n-hexane + n-heptane), maximum positive and minimum with negative value, Deviations in Refractive Index (ΔnD), was were positive for all binary mixtures, Excess Gibbs Energy was negative for all binary ,but maximum positive and minimum with negative value just at system (n-hexane + n-heptane). 7.Excess properties for ternary mixture negative and positive value. 8.Excess properties for fourth mixture negative value.
سهير المبروك دربال (2009)

Abstract Here asphaltene precipitation in petroleum reservoirs during natural depletion and miscible gas injection is modeled for two distinct and new methods (polymer solution and Scott-Magat theory). The first model is based on the polymer solution theory, which is a combination of Miller's combinatorial term with a modified residual term of the original Flory-Huggins theory. The second one is based on the Scott Magat theory to represent solid-liquid equilibria. The models has also been coupled with Peng Robinson equation of state (PR EOS) to describe the phase behavior of asphaltene compounds in crude oil and predict the amount of asphaltene precipitation during injection of carbon dioxide for the miscible displacement of asphaltic crudes. The model treats asphaltene within crude oil as a single pseudocomponent represented by an average molecular weight and molar volume and solubility parameter . The results of both models show an acceptable and good agreement between the real data (field and experimental) and those of the models. As it can be seen from the obtained results of those of the two models, it seems that application of the lattice or polymer solution theories (based on The Miller's combinatorial term) could give better results that are more close to real data.
وداد بلعيد حميدات (2009)