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Article
Hydrodynamic Studies of Bed Expansion in Liquid Solid Fluidized Bed
دراسة هيدروديناميكية لتمدد الاعمدة المسالة المتكونة من الصلب والسائل

Author: Sawsan A. M. Mohammed
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2010 Volume: 16 Issue: 3 Pages: 5398-5410
Publisher: Baghdad University جامعة بغداد

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Abstract

Expanded bed behavior was modeled by using the Richardson-Zaki correlation between the superficial velocity of the feed stream and the void fraction of the bed at moderate Reynolds number. The terminal velocity expression was developed by introducing two empirical parameters, the effective diameter of the particles and an exponent for the term. The Richardson-Zaki exponent constant (n) was found to vary with the density ratio and diameter ratio . It was noted that when the density ratio is less than one, there is no dense phase at the bottom of the test section. However, for density ratio greater than unity, there exists accelerating or dense regime at the bottom of the test section.

تم في هذا البحث تمثيل تصرف الاعمدة المتمددة باستخدام علاقة ريتشاردسن- زاكي بين السرعة الظاهرية للمجرى الداخل ونسبة الفراغ للعمود في حدود معتدلة من رقم رينولدز. تم استحداث علاقة جديدة للسرعة . النهائية وذلك بادخال مقدارين تجريبيين وهما القطر المؤثر لحبيبات الحشوة ومقداراسي للحدوالنسبة بين قطر الحبيبة لعلاقة ريتشاردسن – زاكي يتغير مع الحد (n)لقد وجد ان المقدار الاسياقل من واحد لم يظهر طور . كذلك تم ملاحظة انه عندما تكون نسبة الكثافة وقطر العمودكثيف في اسفل العمود بينما في حالة كون نسبة الكثافة اكبر من واحد ظهرطور كثيف متسارع في اسفل العمود.


Article
Interference Drag Between Cylindrical Particles in Stokes Flow
قوة السحب التداخلية بين جسيمتين اسطوانيتين في جريان ستوكس

Authors: Sawsan A. M. Mohammed --- Abbas H. Sulaymon
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2009 Volume: 27 Issue: 8 Pages: 1654-1658
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this study, the interference effects when two cylinders are placed in series or parallel ina low Reynolds number flow are predicted. For two cylinders with their line of centersperpendicular to the flow, the drag force is lower than an isolated cylinder at small gaps butis greater at large gaps; a maximum is found at a gap of approximately of 7 cylinderdiameters. For cylinders with their line of centers parallel to the flow, the drag on the trailingbody is less than the leading body, which in turn is less than the drag on an isolated cylinder

تم ايجاد التاثيرات التداخلية بين اسطوانتين متماثلتين مرتبة بالاتجاه الطولي مع الجريان مرةوبشكل متعامد مع الجريان مرة اخرى في مدى صغير من رقم رينولدز. دلت النتائج للحالة الاولى على انقوة السحب على الاسطوانة الخلفية اقل من تلك على الاسطوانة المتقدمة والتي هي اقل من قيمة قوة السحبعلى الاسطوانة المعزولة, اما بالنسبة للحالة الثانية فان قوة السحب تكون اقل من الاسطوانة المعزولة عندماتكون المسافة الفاصلة بين الاسطوانتين قليلة وتزداد بازدياد المسافة الفاصلة حتى تصل الى قيمة عظمى عندمسافة حوالي 7 مرات بقدر قطر الاسطوانة.


Article
Improving Treatment Performance of Dissolved Air Flotation System by Using Ionic Liquids as Surfactants

Authors: Sawsan A.M. Mohammed --- Aws Abbas Fadhil
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2015 Volume: 16 Issue: 2 Pages: 31-37
Publisher: Baghdad University جامعة بغداد

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Abstract

The effect of three ionic liquids viz., 1-hexyl-3-methylimidazolium tetrafluoroborate (ILE), 1-hexyl-3-metylimidazolium hexafluorophosphate (ILF) and 1-octyl-3-methylimidazolium tetrafluoroborate (ILG) when used as surfactants on the performance of dissolved air floatation (DAF) was investigated. Experiments were conducted at a temperature of 30-35 ºC, 10ppm ferric chloride as coagulant, 50% recycle ratio, pH 8, and 10 minutes treatment time to find oil and grease (OG) and turbidity removal efficiencies at saturation pressure (2-6) bar.ILs were used at concentration of 50 µl/liter of treated water in two positions in DAF system; the saturation vessel and the treatment tank. The performance using ILs in the saturation vessel were better than that in treatment tank because ILs reduced the surface tension of water, which lead to an increase in the solubility of air in water and eventually increase the microbubble formation. The OG removal efficiency using ILG as an efficient surfactant in saturation vessel was higher than that in the treatment tank and higher than other ILs (ILG>ILF>ILE). The removal efficiency reached about 90% at a saturation pressure of 5 bar, and 85% at 3 bar, which reduces the operation costs. The treated water oil concentration at 3bar was 9.5 ppm, which meets the Iraqi pre-disposal regulatory limit.


Article
Extraction of Phenol from Aqueous Solutions Using Bulk ionic Liquid Membranes

Authors: Sawsan A.M. Mohammed --- Mohammed Saadi Hameed
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2016 Volume: 17 Issue: 1 Pages: 83-97
Publisher: Baghdad University جامعة بغداد

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Abstract

Room temperature ionic liquids show potential as an alternative to conventional organic membrane solvents mainly due to their properties of low vapour pressure, low volatility and they are often stable. In the present work, the technical feasibilities of room temperature ionic liquids as bulk liquid membranes for phenol removal were investigated experimentally. In this research several hydrophobic ionic liquids were synthesized at laboratory. These ionic liquids include (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide[Bmim][NTf2], 1-Hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide[Hmim][NTf2], 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide[Omim][NTf2],1‐butyl‐1‐methylimidazoliumhexafluorophosphate[Bmim][PF6], 1‐hexyl‐1‐methylimidazoliumhexafluorophosphate[Hmim][PF6], 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide[Bmpyr][NTf2], and 1-octyl-3-methyl imidazolium tetra fluoroborate[Omim][BF4]. The distribution coefficients for phenol in these ionic liquids were measured at different pH values and found to be much larger than those in conventional solvents. Through the values of the distribution coefficients and the experiments that were conducted on bulk liquid membrane applying various types of prepared ionic liquids, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide was selected as the best ionic liquid which gave the highest extraction and stripping efficiencies. The effect of several parameters, namely, feed phase pH(2-12), feed concentration(100-1000 ppm), NaOH concentration(0-0.5M), temperature (20-50oC), feed to membrane volume ratio (200-400ml/80ml ionic liquid) and stirring speeds(75-125 rpm) on the performance of the choosen ionic liquid membrane were also studied. The preliminary study showed that high phenol extraction and stripping efficiencies of 97% and 95% respectively were achieved by ionic liquid membrane with a minimum membrane loss which offers a better choice to organic membrane solvents.


Article
The Effect of Asphaltene on the Stability of Iraqi Water in Crude Oil Emulsions

Authors: Sawsan A.M. Mohammed --- Sally D. Maan
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2016 Volume: 17 Issue: 2 Pages: 37-45
Publisher: Baghdad University جامعة بغداد

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Abstract

In the present work, asphaltenes and resins separated from emulsion samples collected from two Iraqi oil wells, Nafut Kana (Nk) and Basrah were used to study the emulsion stability. The effect of oil resins to asphaltene (R/A) ratio, pH of the aqueous phase, addition of paraffinic solvent (n-heptane), aromatic solvent (toluene), and blend of both (heptol) in various proportions on the stability of emulsions had been investigated. The conditions of experiments were specified as an agitation speed of 1000 rpm for 30 minutes, heating at 50 °C, and water content of 30%. The results showed that as the R/A ratio increases, the emulsion will be unstable and the amount of water separated from emulsion increases. It was noticed that the emulsion of Nk crude oil became more stable at basic pH range, and reached to completely stabilized emulsion at pH=12. Whereas Basrah emulsion was stable in both acidic and basic pH ranges. Results indicated that toluene gave a good solubility for asphaltene, and a higher water separation for both crude oil emulsions. A mathematical model to determine the kinetic constants that characterize the coalescence in the emulsions was also developed.


Article
TREATMENT OF A HIGH STRENGTH ACIDIC INDUSTRIAL CHEMICAL WASTEWATER USING EXPANDED BED ADSORBER

Authors: Haider Abbas Shanshool --- Sarmad Foad --- Sawsan A. M. Mohammed
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2011 Volume: 17 Issue: 1 Pages: 103-115
Publisher: Baghdad University جامعة بغداد

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Abstract

Treatment of a high strength acidic industrial wastewater was attempted by activated carbon adsorption to evaluate the feasibility of yielding effluents of reusable qualities. The experimental methods which were employed in this investigation included batch and column studies. The former was used to evaluate the rate and equilibrium of carbon adsorption, while the latter was used to determine treatment efficiencies and performance characteristics. Fixed bed and expanded bed adsorbers were constructed in the column studies.In this study, the adsorption behavior of acetic acid onto activated carbon was examined as a function of the concentration of the adsorbate, contact time and adsorbent dosage. The adsorption data was modeled with Freundlich and Langmuir adsorption isotherms.The amount of acetic acid adsorbed increased with the decrease in initial concentration of acetic acid and increased with the increase in contact time and adsorbent dose. The effects of various important and influencing parameters such as flow rate, bed height, inlet adsorbate concentration on breakthrough curve are studied in details in the column studies.

تم في هذه الدراسة معالجة مياه التصريف العالية الحموضةبواسطة الامتزاز على الكاربون المنشط واستخدمت طريقة الامتزاز ذو الدفعات وباستخدام الاعمدةالثابتة والمتمددة. حيث استخدمت الاولى لايجاد معدل وعلاقة الامتزاز لحامض الخليك علىاالكاربون المنشط بينما استخدمت الثانية لايجاد كفاءة عملية المعاملة وايجاد الاداء. المتغيرات التي تم دراستها هي تركيز المادة الممتزة والزمن وكمية المادة المازة. استخدمت علاقة فرويندلش ولنكمير لتمثيل النتائج. بينت النتائج بان كمية حامض الخليك الممتزة تزداد مع نقصان التركيز الابتدائي للحامض وتزداد مع زيادة زمن التماس وكمية المادة المازة.اما بالنسبة للدراسة باستخدام الاعمدة فان تاثير معدل الجريان وارتفاع الحشوة وتركيز المادة الممتزة على منحني المقاومة تم دراستها بالتفصيل.


Article
Drag Forces under Longitudinal Interaction of Two Particles

Authors: Sawsan A. M. Mohammed --- Abbas H. Sulaymon عباس حميد سليمون
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2007 Volume: 8 Issue: 2 Pages: 1-4
Publisher: Baghdad University جامعة بغداد

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Abstract

Direct measurements of drag force on two interacting particles arranged in the longitudinal direction for particle ? numbers varying from 10 to are conducted using a micro-force measurement system. The effect of the interparticle distance and Reynolds number on the drag forces is examined. An empirical equation is obtained to dacribe the effect of the interparticle distance (l/d) on the dimensionless drag.


Article
Electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor

Authors: Sawsan A. M. Mohammed --- Abbas Hamid Sulaymon --- Ali Hussein Abbar
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2015 Volume: 16 Issue: 4 Pages: 31-43
Publisher: Baghdad University جامعة بغداد

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Abstract

The cathodic deposition of zinc from simulated chloride wastewater was used to characterize the mass transport properties of a flow-by fixed bed electrochemical reactor composed of vertical stack of stainless steel nets, operated in batch-recycle mode. The electrochemical reactor employed potential value in such a way that the zinc reduction occurred under mass transport control. This potential was determined by hydrodynamic voltammetry using a borate/chloride solution as supporting electrolyte on stainless steel rotating disc electrode. The results indicate that mass transfer coefficient (Km) increases with increasing of flow rate (Q) where K_m∝Q^0.402.The electrochemical reactor proved to be efficient in removing zinc and was able to reduce the levels of this metal to lower than 0.7 ppm starting from initial concentration of 48.4 mg dm-3 ppm in 120 minutes using ratio of cathode volume/catholyte volume equal to 0.0075. Sherwood and Reynolds numbers were correlated to characterize the mass transport properties of the reactor as follows: Sh=0.0644〖Re〗^0.3686 〖Sc〗^(1/3)


Article
Phosphorus Removal from Water and Waste Water by Chemical Precipitation Using Alum and Calcium Chloride

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Abstract

Phosphorus is usually the limiting nutrient for eutrophication in inland receiving waters; therefore, phosphorus concentrations must be controlled. In the present study, a series of jar test was conducted to evaluate the optimum pH, dosage and performance parameters for coagulants alum and calcium chloride. Phosphorus removal by alum was found to be highly pH dependent with an optimum pH of 5.7-6. At this pH an alum dosage of 80 mg/l removed 83 % of the total phosphorus. Better removal was achieved when the solution was buffered at pH = 6. Phosphorus removal was not affected by varying the slow mixing period; this is due to the fact that the reaction is relatively fast.The dosage of calcium chloride and pH of solution play an important role in phosphorus removal. The removal efficiency increases with increasing pH, and the optimum dosage of CaCl2 was 60 mg/l. Alum demonstrated much better results in phosphorus removal than CaCl2.

يعتبر الفسفور من المواد الملوثة للماء والتي تؤدي الى عملية التحول في الحياة المائية (Eutrophication) ولهذا فمن الضروري السيطرة على تركيزه في الماء.في هذه الدراسة تم اجراء سلسلة من التجارب باستخدام جهاز (jar test) لايجاد افضل قيمة للرقم الهيدروجيني وكمية المادة الكيمياوية المضافة.لقد وجد ان افضل قيمة للرقم الهيدروجيني في حالة استخدام الشب هو من 5.5-6 وافضل كمية مستخدمة هي 80 ملغم/لتر والتي تعمل على ازالة 83% من كمية الفسفور الذائب في الماء وكانت عملية الازالة افضل عندما تمت السيطرة على قيمة الرقم الهيدروجيني على قيمة 6.لم تتأثر كفاءة الازالة بتغيير الزمن اللازم للتحريك البطئ و ذلك لكون التفاعل سريع.اما في حالة ازالة الفسفور باستخدام كلوريد الكالسيوم فان كمية الكلوريد المضاف والرقم الهيدروجيني للمحلول كان لها دور مهم في عملية الترسيب وان افضل قيمة للرقم الهيدروجيني هو 11 وافضل قيمة لكمية الكلوريد هي 60 ملغم/لتر.دلت النتائج على ان الشب اعطى كفاءة افضل في عملية ترسيب الفسفور بالمقارنة مع كلوريد الكالسيوم.


Article
Oily Wastewater Treatment Using Expanded Beds of Activated Carbon and Zeolite

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Abstract

Two types of adsorbents were used to treat oily wastewater, activated carbon and zeolite. The removal efficiencies of these materials were compared to each other. The results showed that activated carbon performed some better properties in removal of oil. The experimental methods which were employed in this investigation included batch and column studies. The former was used to evaluate the rate and equilibrium of carbon and zeolie adsorption, while the latter was used to determine treatment efficiencies and performance characteristics. Expanded bed adsorber was constructed in the column studies. In this study, the adsorption behavior of vegetable oil (corn oil) onto activated carbon and zeolite was examined as a function of the concentration of the adsorbate, contact time, adsorbent dosage and amount of coagulant salt(calcium sulphate) added . The adsorption data was modeled with Freundlich and Langmuir adsorption isotherms. and it was found that the adsorption process on activated carbon and zeolite fit the Freundlich isotherm model. The amount of oil adsorbed increased with increasing the contact time, but longer mixing duration did not increase residual oil removal from wastewater due to the coverage of the adsorbent surface with oil molecules. It was found that as the dosage of adsorbent increased, the percentage of residual oil removal also increased. The effects of adsorbent type and amount of coagulant salt(calcium sulphate) added on the breakthrough curve were studied in details in the column studies. Expanded bed behavior was modeled using the Richardson-Zaki correlation between the superficial velocity of the feed stream and the void fraction of the bed at moderate Reynolds number.

تم في هذه الدراسة معالجة مياه التصريف الزيتية بواسطة الامتزاز على الكاربون المنشط والزيولايت واستخدمت طريقة الامتزاز ذو الدفعات وباستخدام الاعمدة المتمددة. حيث استخدمت الاولى لايجاد معدل وعلاقة الامتزاز للزيت على الكاربون المنشط والزيولايت بينما استخدمت الثانية لايجاد كفاءة عملية المعاملة وايجاد الاداء. المتغيرات التي تم دراستها هي تركيز المادة الممتزة والزمن وكمية المادة المازة. في هذه الدراسة ، تم فحص سلوك الامتزاز للزيوت النباتية (زيت الذرة) على الكربون المنشط والزيولايت كدالة للتركيز ، وكمية المادة الممتزة وكمية الملح (كبريتات الكالسيوم) المضاف.تم تمثيل النتائج باستخدام علاقات الامتزاز ثابتة درجة الحرارة فروندليتش ولنكمير. ووجد أن معادلة فرويندلش تنطبق على عملية الامتزاز على الكربون المنشط والزيولايت. ان كمية الزيت الممتز تزداد مع زيادة زمن التماس وكذلك وجد ان زيادة المادة المازة ستزيد من نسبة ازالة الزيت. تم ايضا دراسة تاثير نوع المادة المازة المستخدمة على منحني المقاومة.تم تمثيل تصرف الاعمدة المتمددة باستخدام معادلة ريتشاردسن – زاكي بين السرعة الفراغية والجزء البيني للعمود في حدود معتدلة من رقم رينولدز.

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