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)

Abstract This research was an attempt to use the currently available activity coefficient methods with universal sets of parameters to simultaneously predict ternary liquid-liquid equilibrium data. The focus of this research was to calculate phase equilibrium data within fair error using set of Parameters obtained from the above-mentioned models. The significance of this work is to study the liquid-liquid phase equilibrium of the ternary system at several temperatures and to test the capability of the various equilibrium models to correlate these data. A series of liquid-liquid equilibrium measurements were performed by changing the composition of the mixture.The prepared mixtures were placed in the extraction vessel and stirred for 2 h and then left to settle for 4 h. Samples were taken by a syringe from both the upper phase and lower layers. Both phases were analyzed using gas chromatography equipped. Liquid-liquid equilibrium for the ternary system acetonitrile + benzene + n-heptane was measured at 298,313,333 K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models. The UNIQUAC equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. NRTL models satisfactorily predicted the equilibrium compositions. In each of the mentioned the ternary system, the calculated and experimental data were compared. The root mean square deviation (RMSD) between the observed and calculated mole percent for NRTL, UNIQUAC was 1.44%, 1.35% for acetonitrile + benzene + n-heptane
عماد الدين محمد الزغداني (2014)

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)