Digital Repository for Department of Chemical Engineering

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)

دراسة ضمان التدفق هو احدي أهم العمليات التحليلية لمرور الزيت والغاز خلال الأنابيب والمعدات البتروكيميائية. هذه الدراسة تساعدنا فى تصميم وتشغيل وصيانة خطوط الزيت و الغازوخاصة الخطوط الموجودة في أعماق البحار. يعتبر الشمع والهيدريت من أهم المشاكل التى تواجه نقل الزيت والغاز عبر الأنابيب هذه المشاكل تكلف خسائر مالية كبيرة عن طريق اغلاق جزء من انابيب نقل الزيت والغاز. ولتجنب الوقوع فى خطر الهيدريت والشمع يجب ان تكون كل من درجة الحرارة والضغط بعيدة عن تكون الشمع والهيدريت. تضمنت هذه الدراسة تضمنت فحص تأتير كل من اللزوجة, متوسط الوزن الجزئ, نسبة الشمع, سمك العازل, الزمن ودرجة الحرارة الخارجية على ترسب الشمع على جدار أنابيب النقل. وكذلك قمنا بدراسة متى وأين يتكون الهيدريت باختيار زيوت وغازات مختلفة. من أهم النتائج التى تحصلنا عليها من خلال دراسة ترسب الشمع على الأنابيب وتكون الهيدريت كالأتي :أقل لزوجة في الزيوت الشمعية كانت عنده أعلى قيمة ترسب الشمغ علي الأنبوب .زيادة سمك العازل ودرجة الحرارة المحيطة تقلل ترسب الشمع على الأنابيب .زيادة زمن التشغيل تزيد من ترسب الشمع علي الأنابيب .دراسة تكون الهيدريت باستخدام برنامج كمبيوتر (HYSYS وPVTSIM) كانت النتائج المعملية قريبة من النتائج المعملية عند درجة حرارة وضغط منخفض. اضافة مواد كيميائية احدى الطرق التى تبعدنا عن خطر تكون الهيدريت.

Abstract

Flow assurance is the analysis of thermal, hydraulic and production chemistry issues during the flow of fluids through pipelines and process equipments in the oil and gas industry. These issues arise during the design, operation and maintenance of Gas/oil supply systems, which are often in deep water or challenging environments. Flow assurance studies are usually carried out at design and production stages to insure oil and gas flow in pipe lines and process equipment without any problems. Wax and hydrates are problems associated while gas and oil are transported. Wax deposition is a serious field problem encountered during crude oil production that causes plugging of pipe line, well tubing and process equipment. Wax crystals lead to oil high viscosity and decreased pumping capacity. Gas hydrates are a well-known problem in the oil and gas industry and cost millions of dollars in production and transmission pipelines. To prevent this problem, it is important to predict the temperature and pressure under which gas hydrates will form. This work aims to investigate the major flow assurance aspect (wax deposition and hydrates formation) in flow lines. This may include; Effect of oil viscosity, oil wax percent, average moleculer weight of oil, ambient temperature, insulation thickness and time duration on wax deposition rate in pipelines. In addition concerning hydrates, the main important issue is when and where hydrates will form in flow lines and gas pipelines. five different oils and different gases from literature where selected and utilized as working examples.The important results of wax deposition and hydrate formation are as the following: The lowest viscosity of five crude oils give us the maximum total volume deposition.Increasing of insulation thickness and ambient temperature causes decreasing wax layer deposition.Increasing of time duration causes increasing of wax layer thickness. Hydrate formation by using HYSYS and PVTSIM at law temperature and law pressure is closed to the hydrate formation by experimentally. Adding chemicals (inhibitors) saved the gas through a pipeline from the risk of hydrate formation. The obtained results show that wax deposition and hydrates formation can be predicted with good accuracy with computer soft ware.
المبروك فرحات المسلاتي (2014)

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

Against the background due to the energy crisis in the late 1970’s, the pinch analysis has emerged as a powerful tool for the integrated design of process heat networks which include heat exchangers, distillation columns, furnaces, etc..The key strategy of this methodology is to set energy targets prior to design based on basic thermodynamic principles.The subject of this thesis in to apply this analysis to one of the Libyan Refineries, namely Ras Lanuf Refinery, to assess energy utilization of such big energy – consuming plants and to explore the potential of energy as well as capital costs savings based on the finding of applying this analysis. Based on actual operating data collected from the plant and application of the procedure of the pinch analysis to this real case study where a minimum temperature difference approach in the Ras Lanuf refinery heat exchangers design of 10 (ΔT min =10 ) the following results were obtained. Actual rate of energy consumption of the base case design of the refinery is 9MW which is provided by burning fuel oil in the furnace, while the minimum target predicted by the pinch analysis should be 8MW. This amounts to just over 11% energy savings which equivalent to $462,000 per year reduction in the operating cost of the refinery
هويدة الهادي الحبيشي (2011)

Abstract

Cement kiln dust is a major by product in cement manufacture. Methods of disposal, handling, treatment and reuses are a major factors in optimization of a certain cement plant. This thesis concentrates on the uses of cement kiln dust of souk Al Kamees cement plant as Soil amendment and as an adsorpent of Fe, Zn and lead results from sand. The major objectives of these treatments are environmental rather than economical to reduce the landfill disposal of CKD which is major problem in cement industry. CKD is used in agricultural soil amendment.CKD in Souk Alkamees consists primarily of calcium carbonate and silence dioxide, the alkaline by pass process contains highest amount of calcium oxide and lowest loss on ignation [LOI] which become a beneficial for CKD use as a soil amendment to the sand for many especial agricultural products such as potatoes, …etc. This thesis concentrates on the uses of CKD as an adsorbent to remove heavy metals such as Fe, Zn, and Pb from soil. Adsorption column is used to perform the work. Experimental setup discussed in the thesis is used using cement kiln dust as an adsorbent for removal of heavy metals from soil. The major result is to simulate the physical behavior of the process using conventional isotherms available in literature, Langmuir, Freandlish and Drachsal isotherm models have been found to simulate the data with good agreement with experimental work. Characterization of the CKD is made after dehydration process at 150C for 24 hrs. X ray fluorescent equipment is used and the results are reported in the thesis.
محمد محمود الشاهري (2015)

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

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)

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)