| المستخلص: |
منذ ما يزيد عن عقد من الزمان بدأ الإنتاج العالمي من النفوط الخفيفة عالية الكثافة ومنخفضة المستوى الكبريتي يتقلص نسبة إلى غيره من النفوط الأخرى. وقد كان هذا الوضع من بين العوامل التي جعلت مصافي النفط تعاني من عدم القدرة على تلبية الاحتياجات المتزايدة على وقود وسائط النقل المختلفة، وفاقم الأمر التشديد على المعايير البيئية في الصناعة النفطية عبر العالم. ومن ثم بات لزاما على مصافي النفط أن تطور تجهيزاتها التكنولوجية حتى تتمكن من التعامل مع النفوط الخام الثقيلة، لتنتج وقودا أنظف ومشتقات بترولية متوافقة مع المعايير الدولية. وهذا التحدي يطرح كذلك على صناعة التكرير العربية بكل مفاعيله وحدته. تسعي هذه الدراسة لطرح مختلف الخيارات في هذا المجال، وتقدم إلى جانب الطرح الفني للموضوع نماذج دراسية جديرة بالاهتمام.
Petroleum refineries are more than ever motivated to refine heavy crude oils, as a result of the growing demand for petroleum refined product, and the increase in the price difference between heavy and light crudes in the world. Although most of crude oil produced in the member countries of the organization of Arab petroleum exporting countries (OAPEC) are medium sour type, there are many indications refers that the production of heavy crudes will increased dramatically, especially in the countries have a huge reserve of this type of crude, such as Saudi Arabia, Kuwait, Iraq and Syria. Refineries are usually designed to process a certain types of crude oils. Processing different type of crude without modifying the equipment of the process plant to accept different type of crudes, will affect the stability of the operating conditions, and may resulted in unscheduled shutdown of the refinery. The puipose of this paper is to highlight the measures that can make the units in refineries compatible to the variations in feed composition. Attempts have also been made to explore the various options for upgrading heavy crude oils, that can be classified as hydrogen addition (Hydrocracking) and carbon rejection ,through well established thermal conversion processes such as visbreaking, delayed or fluid coking, etc. At present, hydrogen addition techniques are relatively more expensive and most of them are proprietary in nature though the products are clean and environmentally satisfactory. However, selection of any of the technology, alone or in combination, is mainly dependent on many factors such as the location, crude availability, and the economic viability. A different case studies have also been given in this paper for reference.
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