A refinery consists of crude oil operations, unit operations and product blending Operations. In crude oil operations the refinery deals with availability of crude oil and crude oil inventory management. Whereas, product blending deals with the fluctuating market requirement of the blended products. In the whole process the demand flows towards the suppliers, whereas the product flows towards the customers. However, because of volatile raw material prices, fluctuating product demands, quality improvement acts and other changing market conditions, it is difficult to have stable profit margins. In this work, we have covered refinery planning under market uncertainty, flexible scheduling of oil inventory management and the molecular level management for refinery gasoline blending in order to improve refineries competitiveness.