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 Deposition of undesirable materials on water wall side of boiler tube that are operated under forced circulation boiling conditions can cause serious trouble in steam boilers. The present study is concerned with the scaling characteristics of water in the boilers. The effects of heat flux and water velocity were evaluated for water having a total hardness and calcium hardness in the range (TH= 380 to 390 ppm asCaCO3 ) and(CaH= 250 to 298 ppm asCaCO3) respectively. The heat flux ranged from (1.05 x 105) to and water velocity in a vertical annular test section range from 0.51 to 0.75 m/sec (1.67 to 2.5 ft/sec) . The test section consisted of an annular duct 0.050 m (2.0-in) O.D. and 0.033 m (1.33-in ) I.D. A 0.30 m (12-in) section of the concentric core of the annulus was electrically heated. Hot water at 97.0 (370.1) was circulated through the annulus where boiling occurred on the heated section. The temperature range at the Surface of heated section in the annulus was from (105 - 118 ). The results of five tests are reported in this study. The fouling resistance vr. time curves reached an asymptotic value and the average of fouling resistance for Runs (1-5) had been plotted. Chemical analysis of scale deposits indcated that Calcium carbonate and Silica were the man Constituents. At constant surface temperature an increase in velocity from 0.51 to 0.75 m/sec (1.67 -2.5 ft/sec), caused about a 20 percent reduction in the asymptotic fouling resistance.
عادل محمد شنقير (2008)