(52d) Optimization of Possible Upgrading Configuration of Libyan Refineries

In General, the principal refining operations fall into four categories: a) separation of crude oil into various cuts; b) quality enhancement of the certain cuts; c) transformation of heavy cuts into lighter cuts (conversion); d) final preparation of finished products through blending. The most common refinery process includes catalytic, hydro, and thermal cracking units to convert heavy hydrocarbons into light hydrocarbons. They also contain other process units like continuous catalytic reforming, hydro-treating, and hydro-desulfurization units.

Libya is an important contributor to the global supply of light and sweet crude. It has five domestic refineries; all of them are simple hydro-skimming units. Therefore the upgrading projects in many oil refineries must be considered to cover the local consumption of gasoline and utilization of the advantage of high quality Libyan crude oil. Different alternatives for the upgrading can be tackled. Either direct upgrading of the atmospheric residue, or first subject the atmospheric residue to vacuum distillation then upgrade the vacuum residue, and vacuum gas oil, to more valuable and lighter products. To study these possibilities a very comprehensive calculation model was prepared. The model included most of the Libyan crude oil assays and up to data petroleum refineries technologies from point of yield and product properties. The model is capable to determine the yield of most known products and their specifications beside the cost estimation and financial analysis. The model is used to determine the suitable configuration of Ezzawia refinery upgrading project. The different scenarios were analyzed including delayed coking unit and residue fluidized catalytic cracking (RFCC). The results were evaluated in terms of lowest cost, higher profitability and fulfil of Libyan fuel demand. The best scenario was RFCC best on olefin (propylene operation) with the yield of propylene ranging between 14-18 % on atmospheric residue.