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Article
Dewaxing of Distilate Oil Fraction (400 – 500 ºC) Using Urea

Authors: Safaa R.Yasin --- Abdul-Halim A.K. Mohammed
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2007 Volume: 13 Issue: 1 Pages: 1268-1281
Publisher: Baghdad University جامعة بغداد

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Abstract

De-waxing of lubricating oil distillate (400-500 ºC) by using urea was investigated in the present study. Lubricating oil distillate produced by vacuum distillation and refined by furfural extraction was taken from Al-Daura refinery. This oil distillate has a pour point of 34 ºC. Two solvents were used to dilute the oil distillate, these are methyl isobutyl ketone and methylene chloride. The operating conditions of the urea adduct formation with n-paraffins in the presence of methyl isobutyl ketone were studied in details, these are solvent to oil volume ratio within the range of 0 to 2, mixer speed 0 to 2000 rpm, urea to wax weight ratio 0 to 6.3, time of adduction 0 to 71 min and temperature 30-70 ºC). Pour point of de-waxed oil and yield of wax produced were determined to show the effect of these operating conditions. The most favorable operating conditions were solvent to oil volume ratio of 1, mixer speed of 1500 rpm, urea to wax weight ratio of 5, time of adduction of 13 min and temperature of 30-52 ºC.

يتناول هذا البحث عملية إزالة الشمع من مقطر زيت التزييت باستخدام اليوريا. مقطر زيت التزييت الذي تم التعامل معه في هذا البحث مأخوذ من مصفى الدورة والمنتج بواسطة التقطير التجزيئي تحت الضغط المخلخل ( vacuum distillation ) والمعالج بطريقة الاستخلاص بالفورفورال( furfural extraction). هذا المقطر الزيتي له حدود درجة غليان بين 400 – 500 ْم ونقطة انسكاب 34 ْم. تم استخدام مذيبين لغرض تخفيف مقطر زيت التزييت هما مثيل ايزوبيوتيل كيتون ( methyl isobutyl ketone) وميثيلين كلورايد (methylene chloride ). الظروف التشغيلية لتفاعل اليوريا مع الشمع البارافيني المتواجد في مقطر زيت التزييت بوجود مذيب مثيل ايزوبيوتيل كيتون ( MIBK ) تم دراستها بالتفصيل, وهي نسبة حجم المذيب الى حجم الزيت ضمن حدود صفر– 2 ، سرعة الخلاط ضمن حدود صفر– 2000 دورةدقيقة ، نسبة وزن اليوريا إلى وزن الشمع الموجود في الزيت ضمن حدود صفر– 6.3 ، وزمن التبريد ( التفاعل) ضمن حدود صفر– 71 دقيقة, ودرجة الحرارة ضمن حدود 30– 70 ْم. درجة الانسكاب للزيت (pour point ) الناتج من عملية إزالة الشمع تم قياسها وكذلك النتاج ( yield ) للشمع المستخلص تم حسابه لغرض بيان تأثير الظروف التشغيلية آنفة الذكر. أفضل ظروف تشغيلية تم التوصل إليها هي نسبة حجم المذيب الى حجم الزيت بمقدار 1, سرعة الخلاط بمقدار 1500 دورةدقيقة , نسبة وزن اليوريا إلى وزن الشمع الموجود في الزيت بمقدار 5 , وزمن التبريد ( التفاعل) بمقدار 13 دقيقة , ودرجة الحرارة بمقدار 30– 52 ْم .


Article
HYDRODESULFURIZATION OF THIOPHENE OVER CO-MO/AL2O3 CATALYST USING FIXED- AND FLUIDIZED-BED REACTORS

Authors: Saad Hanash Ammar --- Abdul Halim A-K Mohammed
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2011 Volume: 17 Issue: 1 Pages: 92-102
Publisher: Baghdad University جامعة بغداد

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Abstract

The present work reports a direct experimental comparison of the catalytic hydrodesulfurization of thiophene over Co-Mo/Al2O3 in fixed- and fluidized-bed reactors under the same conditions. An experimental pilot plant scale was constructed in the laboratories of chemical engineering department, Baghdad University; fixed-bed unit (2.54 cm diameter, and 60cm length) and fluidized-bed unit (diameter of 2.54 cm and 40 cm long with a separation zone of 30 cm long and 12.7 cm diameter). The affecting variables studied in the two systems were reaction temperature of (308 – 460) oC, Liquid hourly space velocity of (2 – 5) hr-1, and catalyst particle size of (0.075-0.5) mm. It was found in both operations that the conversion increases with increasing of reaction temperature, slightly decreases with increasing of liquid hourly space velocity and not affected by particle size. Also a kinetic analysis was performed for thiophene hydrodesulfurization reaction in fixed bed reactor and the results indicate that the reaction kinetics are not affected by pore and film diffusion limitations. The results of the comparison between the two reactors indicate that a low conversion was obtained in a fluidized bed than in fixed bed over the range of conditions studied. The lower conversion can be attributed to the gas that bypasses the bed in the form of bubbles or channels.

تم في هذا البحث دراسة تفاعل هدرجة الثيوفين لازالة الكبريت بوجود عامل مساعد صلب وهو الكوبولت – مولبيديوم المحمل على الالومينا.وذلك في نوعين من المفاعلات وهما المفاعل ذو الطبقة الثابتة والمفاعل ذو الطبقة المميعة. تم بناء منظومتين ريادية مكونة من مفاعل الطبقة الثابتة (ذو قطر 2,54 سم وطول 60 سم) ومفاعل الطبقة المميعة (ذو قطر 2,54 سم مطول 40 سم) الهدف من هذا الدراسة هو مقارنة اداء كل من هذين المفاعلين تحت نفس الضروف من درجة حرارة (308 -460) مه وسرعة حجمية (2-5) سا-1، وحجم جسيمة العامل المساعد (استخدمت ثلاث مديات لحجم جسيمة العامل المساعد:(0,075 – 0,15) ملم, (0,15 – 0,3) ملم, (0,3 – 0,5) ملم, بالاضافة للحجم الاصلي (1 (2 – 5) ملم).اظهرت النتائج في تجارب المفاعل ذو الطبقة الثابتة تأثر التحول كثيرا بتغيير درجة حرارة التفاعل حيث يزداد التحول بزيادة درجة الحرارة ويتأثر قليلا بتغيير السرعة الحجمية ولا يتأثر بتغيير حجم جسيمة العامل الساعد. كذلك ضهرت نتائج مشابهة في تجارب المفاعل ذو الطبقة المميعة. استنتج من هذه النتائج ان حركية تفاعل هدرجة الثيوفين بوجود العامل المساعد الكوبلت - موليبيديوم المحمل على الالومينا لا تتأثر بمقاومة الانتشار الداخلي لجسيمة العامل المساعد (داخل المسامات) وكذلك لا تتأثر بمقاومة الانتشار الخارجي للجسيمة (الانتشار الغشائي).بصورة عامة وبمقارنة الاداء بين المفاعلين, اظهرت النتائج حصول تحول اقل في المفاعل ذو الطبقة المميعة عنه في المفاعل ذو الطبقة الثابتة وذلك بسبب مرور قسم من الغاز المتفاعل الداخل خلال فقاعات او قنوات في طور الفقاعات ولا يمر على العامل المساعد في الطور المستحلب في المفاعل ذو الطبقة المميعة.


Article
Alkylation of Benzene with Long Chain Olefins Over Solid-Acid Catalyst

Authors: Ali M. Ridha --- Abdul Halim A. K. Mohammed
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2009 Volume: 15 Issue: 2 Pages: 3620-3632
Publisher: Baghdad University جامعة بغداد

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Abstract

This investigation is concerned with the linear alkylbenzene production reaction by the alkylation of benzene with long chain olefins C10-C13 over various prepared solid acid catalysts. The alkylation process was studied at different reaction temperature, Weight hourly space velocities and with constant pressure and benzene/olefin ratio. The liquid-phase of alkylation of benzene with olefins carried out over prepared tungstophosphoric acid supported on SiO2 with 5, 10, 20 and 30 wt. % loading catalysts in a fixed bed reactor. Prepared tungstophosphoric acid supported over silica catalyst with 30 % loading gave the highest conversion of olefin to linear alkylbenzene (94% conversion) at 398K and 5h-1. The study of the kinetics of benzene alkylation with olefins over these prepared catalysts reveals that the reaction is second order. The value of Thiele modulus for each prepared catalysts is lower than 0.4 which means that diffusion free regime and the surface reaction is the limiting step for the alkylation process.

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Article
Adsorption of BTX Aromatic from Reformate by 13X Molecular Sieve

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Abstract

This work deals with separation of the aromatic hydrocarbons benzene, toluene, and xylene (BTX) from reformate. The separation was examined using adsorption by molecular sieve zeolite 13X in a fixed bed process. The concentration of aromatic hydrocarbons in the influent and effluent streams was measured using gas chromatography. The effect of flow rate and bed length of adsorbent on the adsorption of multicomponent hydrocarbons and adsorption capacity of molecular sieve was studied. The tendency of aromatic hydrocarbons adsorption from reformate is in the order: benzene >toluene>xylenes.

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Article
FLUID CATALYTIC CRACKING OF PETROLEUM FRACTION (VACUUM GAS OIL) TO PRODUCE GASOLINE

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Abstract

In this work, fluid catalytic cracking of vacuum gas oil to produce gasoline over prepared faujasite type Y zeolite was investigated using experimental laboratory plant scale of fluidized bed reactor. The catalytic activity of prepared faujasite type NaY, NaNH4Y and NaHY zeolites was investigated. The cracking process was carried out in the temperature range 440 to 500 oC, weight hourly space velocity (WHSV) range 10 to 25 h-1 ,and atmospheric pressure . The catalytic activities of the prepared faujasite type NaY , NaNH4Y and NaHY zeolites were determined in terms of vacuum gas oil (VGO) conversion, and gasoline yield . The conversion at 500oC and WHSV10 hr-1 by using faujasite type NaY, NaNH4Y and NaHY zeolite were 50.2%, 64.1% and 69.5wt% respectively. The gasoline yield using the same operating conditions were 24.8%, 30.5% and 36.8wt% respectively. Gas chromatographic analysis of produced gasoline shows that the paraffin, olefin, and aromatic content change considerably with the end point temperature of gasoline fraction.

تم استخدام التكسير الحفازي المائع لزيت الغاز الذي حصل عليه من التقطير الفراغي لمتبقي التقطير الجوي في وحدة الزيوت في مصفى الدورة باستخدم العامل المساعد فايوجاسيت نوع Y زيولايت المحضر . درست الفعالية الحفازية للفيوجيسايت بصيغة الصوديوم NaY , و صيغة الامونيومNaNH4Y و صيغة الهيدروجين NaHY زيولايت باستخدام وحدة تجريبية بحدود درجات الحرارة بين 440 – 500 oC وسرعة فراغية بين 10 – 25 سا-1 .تم تعيين الفعالية الحفازية للفيوجيسايت بصيغة الصوديوم NaY , و صيغة الامونيومNaNH4Y و صيغة الهيدروجين NaHY زيولايت بصيغة تحويل المتفاعلات الى مختلف النواتج ونسبة الكازولين الناتج .لقد كانت نسبة تحويل المتفاعلات الى نواتج عند درجة حرارة 500 oC وسرعة فراغية 10 سا-1 50.2% و 64.1% و 69.5% على التوالي. وان انتاجية الكازولين لنفس الظروف التشغيلية كانت24.8% و 30.5% و 36.8% على التوالي .بينت تحليل الغازالكروماتوغرافي Gas Chromatography للكازولين المنتج بان نسبة البرافينات ,الاوليفينات والاروماتيات تتغير تبعا لتغير درجة حرارة نهاية التقطير لمقطع الكازولين .


Article
The Effect of Solvent Extraction of Light Lubricating Oilon Viscosity Index and Chemical Composition

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Abstract

An investigation was conducted for the improvement of viscosity index of light lubricating oil fraction (40 stock) obtained from vacuum distillation unit of lube oil plant of Daura Refinery, using solvent extraction process.In this study furfural solvent was used to extract the undesirable materials which reduce the viscosity index of raw lubricating oil fraction.The studied effecting variables of extraction were extraction temperature range from 70 to 110°C, and solvent to oil ratio range from 1:1 to 4:1 (wt/wt).The n-d-M method was used for calculation of carbon distribution and structural group analysis of the raffinate produced from furfural extraction.Also the three component phase diagram for a mixed-base oil and furfural at different temperature was drawn.The results of this investigation show that the viscosity index of lubricating oil fraction increases with increasing extraction temperature and increasing the solvent to oil ratio and reaches 115.6 at extraction temperature 110°C and solvent to oil ratio 4:1.Further more, the results show that the viscosity, refractive index, density, sulfur content and percentage yield of produced raffinate were decreased as the extraction temperature or solvent to oil ratio increases for extraction process.


Article
The Effect of TCE Addition on the Performance of Catalytic Isomerization of n-Hexane

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Abstract

n-Hexane conversion enhancement was studied by adding TCE (Trichloro-ethylene) on feed stream using 0.3%Pt/HY zeolite catalyst. All experiments were achieved at atmospheric pressure and on a continuous laboratory unit with a fixed bed reactor at a temperature range 240-270◦C, LHSV 1-3h-1, H2/nC6 mole ratio 1-4.By adding 435 ppm of TCE, 49.5 mole% conversion was achieved at LHSV 1h-1, temperature of 270ºC and H2/nC6 mole ratio of 4, while the conversion was 18.3 mol% on the same catalyst without adding TCE at the same conditions. The activation energy decreased from 98.18 for pure Pt/HY zeolite to 82.83 kJ/mole by adding TCE. Beside enhancement the activity, selectivity and product distribution enhanced by providing DMB (Dimethyl butane) which have higher octane number as compared with 0.3%Pt/HY zeolite. Indeed the increase of the 2.2-DMB/2,3DMB ratio with n-hexane conversion is more pronounced with TCE than with pure Pt/HY zeolite.

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Article
Characterization and Cracking Activity of Zeolite Prepared from Local Kaolin

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Abstract

The synthesis of zeolite NaX from locally available kaolin has been studied. The operating conditions for zeolite NaX production from kaolin with good crystallinity were as follows; a gel formation step of metakaolin in alkaline medium in presence of additional silica to crystallize the zeolite was achieved at 60 oC for 1 hr,and with stirring. In ageing step of the reactants at room temperature for 5 days and crystallization step at 87±2 oC for 24 hr. The catalytic activity of catalyst prepared from local kaolin was studied by using cumene cracking as a model for catalytic cracking and compared with standard HY zeolite and HX zeolite catalysts. The activity test was carried out in a laboratory continuous flow unit with fixed bed reactor at duration time in the range 10-240 minutes, temperature 823 K, and LHSV 1 h-1. The prepared and the standard catalysts were characterized by atomic absorption, X-Ray Diffraction Analysis, Fourier Transform Infrared Spectroscopy, surface area and pore volume.

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Article
Kinetic Study of Catalytic Hexane Isomerization

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The isomerization of n-hexane on platinum loaded acidic zeolite was studied at atmospheric pressure, H2/nC6 molar ratios of 1-4 and temperature range of 240-270ºC. The measured kinetic data were fitted to an equation based on the bifunctional mechanism and by using independently obtained dehydrogenation and adsorption data. The activation energies of protonation (ΔHpro) and the elementary isomerization step (Eact,iso) and as well as the corresponding preexponential factor were simultaneously determined. The observed values of both ΔHpro and Eact,iso are in agreement with the results of quantum-chemical calculations.

تم تحضير العامل المساعد 0.3wt%Pt/HY-zeolite بطريقة التحميل الرطب واستخدمت لازمرة الهكسان الاعتيادي.اجريت التجارب المختبرية بضغط جوي في منظومة ريادية تحتوي على مفاعل ذو الحشوة الثابتة وبدرجات حرارية تراوحت بين 240-270 °م وسرع فراغية 1-3 سا-1 والنسب المولية للهيدروجين الى الهكسان الاعتيادي 1-4.تم اشتقاق المعادلة العامة لسرعة التفاعل بالاعتماد على ميكانيكية ثنائية الدالة .استخدمت البيانات المتوفرة في الادبيات لحساب ثوابت التوازن لعملية الامتصاص وازالة الهيدروجين.ان قيمة طاقة التنشيط لتفاعل الازمرة هي 119.7 كيلو جول/مول في حين قيمة انثالبية تفاعل توليد البروتونات -79 كيلو جول/مول.

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Article
Effect of Promoters on the Catalytic Activity of the Iosmerization Catalyst

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The crystalline zeolite, namely faujasite type Y with SiO2/Al2O3 mole ratio of 5 was used as raw material for preparation of isomerization catalysts. A 0.5 wt % Pt/HY-zeolite catalyst was prepared by impregnation of the decationized HY-zeolite with chloroplatinic acid. The dectionized HY-zeolite was treated with HCl, HNO3 and HI promoters using different normalities and with different concentrations of Sn, Ni and Ti promoters by impregnation method to obtain acidic and metallic promoters' catalysts, respectively. A 0.5 wt% of Pt was added to above catalysts using impregnation method. Isomerization of n-hexane was carried out at different prepared catalysts. The isomerization temperature varied from 250–325° C over weight hourly space velocity (WHSV) 1.6 h-1. The pressure and hydrogen to feed mole ratio were kept constant at 1bar and 2 mol/mol, respectively.The comparison between the above prepared catalysts shows that the total isomer yield during the process with Sn-Pt /HY- zeolite catalyst was higher than the other catalysts and, reached to 63.95% vol. A 0.5 wt% of W and Zr was added to Sn-Pt/HY-zeolite catalyst by impregnation method to obtain W and Zr co-metal promoters catalysts. Isomerization of n-hexane was investigated using W and Zr co-metal promoters catalyst at the same operating conditions and the yield of isomers reached to 81.14% vol.and 79.07%vol.,respectively.

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