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Article
Effect of Different Operating Conditions on the Corrosion of Carbon Steel in Oxygenated Sodium Sulphate Solution

Authors: Sara A. Sadek --- Basim O. Hasan
Journal: Journal of Petroleum Research & Studies مجلة البحوث والدراسات النفطية ISSN: 22205381 Year: 2013 Volume: 191 Issue: 9th Pages: 62-89
Publisher: Ministry of Oil وزارة النفط

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Abstract

Carbon steel is a major metal used in manufacturing of the equipments used in petroleum industry and it is subject to different operating conditions causing various corrosion attacks. Corrosion of carbon steel in sodium sulphate solution (Na2SO4) under flow conditions was investigated using rotating cylinder electrode (RCE) for a range of rotation velocity (0 – 2000 rpm) and temperatures (32 - 52 oC). The corrosion rate was determined by using both weight loss method and electrochemical polarization technique (limiting current density). Different salt concentrations were investigated ranged from 0.01 to 0.4 M. The effect of time (or corrosion product formation) and the effect of oxygen concentration through air bubbling in the solution were also investigated and discussed. The results showed that increasing rotational velocity leads to a considerable increase in the corrosion rate represented by limiting current density. The corrosion rate had unstable trend with salt concentrations and temperature. Generally, the corrosion rate decreased appreciably with time due to the formation of corrosion product layer depending on rotational velocity, temperature, and oxygen concentration. It was found that, air pumping through the salt solution leads to a considerable increase in the limiting current density (iL) depending on rotational velocity, temperature, and time.


Article
HYDROCHEMICAL SITUATION OF SHARI PLAYA LAKE BRINES AND THE CONTRIBUTION OF THE FEEDING WATER TO THE FORMATION OF EVAPORITE MINERALS, CENTRAL IRAQ
الوضع الهيدروكيميائي لمنخفض الشاري والمياه المغذية لها ومساهمتها في تكون المعادن الملحية، وسط العراق

Authors: Habib R. Habib حبيب رشيد حبيب --- Yehya T. Al-Rawi يحيى توفيق الراوي --- Rafaa Z. Jassim رافع زائر جاسم
Journal: Iraqi Bulletin of Geology and Mining مجلة الجيولوجيا والتعدين العراقية ISSN: 18114539 Year: 2014 Volume: 10 Issue: 2 Pages: 21-40
Publisher: Ministry of Industry and Minerals وزارة الصناعة والمعادن

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Abstract

Shari Playa is a closed elongated basin about 20 Km long and (3 – 5) Km wide; located about 150 Km north of Baghdad. It is characterized by the presence of a lake in winter which dries out to form salt playa in summer. The lake water concentrates by evaporation to form salt crust; composed of sodium chloride and sodium sulphate. Since the playa is a structural depression, many springs are developed inside it as a result of faults intersections. The water and brines in the Shari Playa basin indicate three major groups of water: Na+ – Cl– – SO4=; Ca2+ – SO4= and Na+ – Ca2+ – SO4=. Where the second cations and anions concentrations vary in different water sources in Shari Playa basin, other subdivisions may be recognized giving different water types. The supplied water to the depression strongly contributes to the formation of glauberite, gypsum and thenardite in the lake sediments, especially in the central part which is characterized by the presence of organic matter in the sediments. The water and brines are of different hydrochemical characteristics and contributes to the formation of different evaporite minerals or to dissolve them depending on their concentrations. The lake water precipitates gypsum at first, then glauberite forms in the deepest part of the playa lake when the water volume decreases to occupy the central part only. The concentration of the remaining brine increases due to evaporation, where Na+ is high enough to alter gypsum to glauberite [Na2Ca(SO4)2]. Thenardite (Na2SO4) forms in the salt crust when all Ca2+ is consumed from the lake brine before the NaCl precipitation. It also forms within the black mud slurry after ending of glauberite formation, which consumes the Ca2+ in the brine.

منخفض الشاري حوض شبه مغلق يبلغ طوله حوالي20 كم وعرضه يتراوح بين(5 – 3) كم ويقع على بعد150 كم شمال بغداد. يتصف هذا المنخفض بتكون بحيرة في الشتاء، سرعان ما تجف في الصيف مكونةً منخفض ملحي. تتركز مياه البحيرة بالتبخير مخلفةً قشرة ملحية تتألف من كلوريد الصوديوم وكبريتات الصوديوم. وحيث أن المنخفض ذو أصل تركيبي، فإن العديد من العيون قد تكونت داخل المنخفض نتيجة تقاطع الصدوع ذات الإتجاهات المختلفة. تظهر الدراسة أن هناك ثلاثة أنواع رئيسية من المياه وهي: Na+ – Cl– – SO4= و Ca2+ – SO4= و Na+ – Ca2+ – SO4= وضمن هذه المجاميع الرئيسية توجد تقسيمات ثانوية أخرى نتيجة تغاير تواجد الأيونات الموجبة والسالبة من مصدر إلى آخر من هذه المياه. تعتبر المياه التي يتزود بها المنخفض مسؤولة بشكل كبير عن تكون معادن الگلوبرايت والجبسم والثنردايت في رسوبياته وخصوصاً في الجزء المركزي منه والذي يتصف بوجود المواد العضوية ضمن الطبقة الطينية السوداء خفيفة القوام، حيث إن هذه المياه أو المحاليل ذات صفات جيوكيميائية مختلفة وتراكيز مختلفة قد يؤدي بعضها الى ترسيب معدن معين والبعض الآخر إلى معدن آخر أو قد يساهم في إذابة المعادن الملحية المترسبة. يترسب معدن الجبس من مياه البحيرة أولاً، ثم يتبعها ترسب معدن الگلوبرايت في المنطقة العميقة من البحيرة، حينما تتقلص مياه البحيرة لتغطي الجزء المركزي منها. في هذه المرحلة يزداد تركيز محاليل البحيرة نتيجة التبخير بحيث إن تركيز أيون الصوديوم يكون كافياً لتحويل الجبسم الى گلوبرايت. [Na2Ca(SO4)2] يترسب معدن الثنردايت (Na2SO4) في القشرة الملحية بعد أن يستهلك كل تركيز أيون الكالسيوم من المحاليل قبيل ترسيب كلوريد الصوديوم. يتكون الثنردايت أيضاً في الطبقة الطينية السوداء بعد اكتمال تكون الگلوبرايت الذي يستهلك أيون الكالسيوم من محاليل هذه الطبقة.


Article
Proximate Composition, Mineral Contents and the effects of Sodium Sulphate Salts on Emulsion Capacity and Stability of Mushroom Species obtained from Nigeria

Authors: Abulude F.O --- Ndamitso M.M --- Akinnusotu A --- Elisha J.J --- et al.
Journal: Iraqi Journal of Science المجلة العراقية للعلوم ISSN: 00672904/23121637 Year: 2018 Volume: 59 Issue: 2C Pages: 986-997
Publisher: Baghdad University جامعة بغداد

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Abstract

The proximate composition, mineral contents and the effects of sodium sulphate salts on emulsion capacity (EC) and stability (ES) of mushroom species M1 – Lentinus subnudus Berk, M2 – Chlorophyllum molybditis, M3 – Volvariella esculenta, M4 – Coprinus tramentarius, M5 – Pleurotus ostreatus Jacq, M6 – Termitomyces microcarpus, and M7 – Pleurotus pulmonarius obtained from Nigeria were investigated using standard methods for analyses. The mean of some of the results is: Crude protein: 9.1±0.15 -13.80±0.15%, Crude fibre: 4.15±0.02 – 7.08±0.59%, Na: 177±2.56 – 910±2.56 mg/100 g, P: 480±2.31 – 884±2.43 mg/100 g and Cu: 0.23±0.23 – 0.23±0.23 mg/100 g. In the study, EC and ES were affected by different salt concentrations. In water, the EC results varied from 76.26±20.17 (M2) to 85.70 ± 20.17% (M7) and significantly differed from one another at p > 0.05. The EC of samples in different salt concentrations ranged as follows: 64.48 -86.18, 68.18 - 75.10, 67.18 - 74.51, and 61.48 -75.01% at 2, 4, 6, 8% of the salt concentrations respectively. Salt applications gave lowest ES and EC. These results indicated the interaction between the oil, salt solutions, the mushroom samples, and the blender used to form the emulsions. In stable ES, the interfacial area did not change with time. Consequently, such emulsions have a constant turbidity. In this report, it was observed that coalescence and oiling-off caused an irreversible reduction in the interfacial area. In conclusion, the good emulsifying capacity and stability showed the usefulness of the samples in the food industries and formulations

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