Abstract Recently more than 150 million tonnes of plastics were produced in the world. On the one hand, the consumption and production of polymers are increasing, on the other hand as landfill and incineration become more expensive and less accepted .The increasing amount of polymer wastes from them generates further mainly environmental problems. The recycling of plastic wastes is gaining increasing importance. Pyrolysis is one promising method for the treatment of mixed and contaminated plastic wastes. In this way the plastic wastes are converted into fuels or other valuable feedstock for the petrochemical industry. In present work catalytic cracking of waste plastics blend with HGO [Libyan gas oil supplied by the Zawia Oil Refinery Company boils in the range of 275-375Cº] was investigated using H-ZSM5and H-BETA. Reaction systems that were studied included high density polyethylene HDPE and polypropylene blend with HGO, reactions were carried out in one litre micro autoclave reactor under different conditions of weight, temperature and type of catalyst, The optimum conditions were 2.5% catalyst by weight of total feed stock, one hour, atmospheric presser and three temperatures selected 400Cº, 425Cº and 450Cº. The product distribution for the system [plastics and HGO] provided some good results high yield of liquid [gasoline] up to 210Cº, gases and small amount of heavy oils. Some analysis was used to qualify and quantify the product. The results from GC.MS analysis showed that the yield of gasoline (c5-c12) over H-ZSM5 higher than H-BETA. In case of 5%PP, 15%HDPE and 80%HGO over H-ZSM5 at 450Cº, 96% total conversion achieved. The result from TGA in the same case is 15% by weight. Also the theoretical calculations to quantify the produced gases after burring of waste plastic in rotary kiln reactor have been evaluated. it is found that the suitable ratio of CO:H2 to produce methanol is 7:1
بسمة محمود التونسي (2010)

نظرا للنقص الكبير في كمية المياه الجوفية نتيجة لنقص كمية مياه الأمطار و المياه الصالحة للشرب عامة وعدم وفرة المياه في المناطق النائية وشبه القاحلة حيث تتوفر الطاقة الشمسية وتشح المياه مما يجعل للطاقة الشمسية أهمية كبيرة في تحليه المياه و التقليل من استعمال الطاقة التقليدية التي تصاحبها انبعاثات المسببة للمشاكل البيئية مثل الانحباس الحراري.الهدف من هدا البحث هو تصميم و دراسة تجريبية لأداء المحليات الشمسية نوعية الحوض(basin type solar still ) والمقطر الشمسي نوعية الفتيلة المبللة (tilted –wick solar still ) و المربوطة بالمجمعات الشمسية لغرض تسخين المياه قبل دخولها للمقطر. وقد تم استعارة نموذج رياضي مناسب لمحاكاة أداء المحليات الشمسية التي يتم دراستها ومقارنة الجانب العملي مع الجانب النظري و الذي يستفاد منه في معالجة المشاكل المتوقعة في تصميم المقطر . وقد تم مقارنة معدل إنتاجية المياه في وجود مجمع شمسي وفى عدم وجوده. حيث وجدنا أن معدل إنتاجية نوع (tilted wick) فى وجود مجمع شمسي كان 5.307lm2day عند معدل إشعاع شمسي 676.537wm2 ,وإنتاجية نوع ((basin في وجود مجمع شمسي day 3.333lm2 عند إشعاع شمسي 696.19wm2 , وإنتاجية نوع (basin) في عدم وجود مجمع شمسي day 3.025lm2 عند معدل إشعاع شمسي 721.49wm2 وقد وجدنا أن تركيز الأملاح الصلبة الدائبة كانت 3080mg/l ونقصت بعد عملية التحلية إلى 36.8mg/l و تركيز أيون الكلور كان 475mg/l و نقص إلى 2.2mg/l . حيث تعتبر الطاقة الشمسية هي من أكثر أنواع الطاقة ملائمة للاستعمال في الوقت الحالي لولا انخفاض معدل الاستفادة منها حاليا على نطاق تجارى واسع وتجرى الآن أبحاث كثيرة لتطوير وإيجاد وسائل مناسبة للحصول على الطاقة الكافية. Abstract The problem of drinking water shortage is a worldwide issue that made millions of people suffers this shortage. Different classical energy processes were used to partly solve the problem, but they were suitable only for large population areas due to their high capital, operation and maintenance cost. For these reasons, alternative methods must be sought for rural arid areas. This method uses solar energy to drive basin-type and tilted-wick-type solar stills to produce distilled water. The performance of the stills was also studied when they were connected to external solar collector to preheat the feed water to the stills. The present work deals with studying and modeling of solar stills. The basic idea of the work is to check the production of basin still and tilted wick still using solar energy for solar desalination, using brackish water with total dissolved solids (T.D.S) equal to 3080mg/l and ion chloride concentration of 475mg/l)(35) and solar energy. The still is basically a rectangular basin lined with black or blackened porous material that acts as the solar energy collector. The still was constructed from galvanized iron steel with dimensions 52×75×6 cm. the base area of 52×75 cm. The still inclined at 13o. Distilled water volume collected was recorded continuously for each hour. The productivity of tilted type still with preheated water was 5.307 L/m2 day at an average solar radiation of 676.537 w/m2. The productivity of basin type solar still with preheated water was 3.333L/m2day at an average solar radiation 696.19 w/m2. The productivity of basin type solar still without preheated water was 3.025 L/m2day at an average solar radiation 721.49w/m2. The T.D.S is 36.8mg/l, and ion chloride concentration is 2.2mg/l(35). The developed mathematical model from energy and mass balance on the system was used to predict the performance of the still. It was found that the model predicted inlet temperature and glass temperature well with that one’s measured experimentally. The productivity predicted from the model was far from that measured experimentally. This was due to the many assumption made in the development of the model.
زينب أحمد دالي (2011)

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)