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 Matrix acidizing is a stimulation method commonly used to remove near wellbore damage and restore original formation permeability. It involves the injection of acid into formations at pressures below the fracture pressure. Acid flows down the well into the reservoir, and then reacts with the rock such that any near wellbore permeability damage created by meling or completion fluids can be removed and apparent permeability increased. A matrix acidizing treatment can be' applied to either a sandstone or a carbonate reservoir. Different acids are used because different minerals are involved in these treatments. Hydrochloric acid (HCI) is usually used in carbonate reservoirs to react with carbonates. Hydrofluoric acid (HF) or mixture of Hydrofluoric acid (HF) with Hydrochloric acid (HCI) is commonly used in sandstone porous media to react with silicates and feldspars in the rock. Since the mechanisms of acid reactions with these two types of rock are different, results of the treatments are different as well. In sandstone matrix acidizing, permeability increase behind the acid front is relatively homogeneous. The flow and reaction of acid in carbonate porous media results in the formation of highly conductive flow channels, commonly referred to as wormholes. In the present work we have studies the first study to test the optimal acid flux theory presented by Wang (1) with several independent sets of experimental data. The model was comparing with field data. The second study we use model presented by McCune and Fogler.(2) This previous studies on mathematical modeling of the chemical reactions between sandstone and mud acid. This model is lumped-parameter model. The lumped-parameter model simplifies the chemistry of the dissolution of sandstone minerals with mud acid. The models are compared with the experimental data at different flow rates.
عبد ربه ادريس بوسدرة (2010)