Plant-wide planning and marginal value analysis for a refinery complex

Abstract Recently, besides the production of petroleum products and fuels, modern refinery complexes are being reformed to become “energy plants” that are able to export electricity and steam. The success of this reformation depends, heavily on effective integration of the production and the energy system. In view of this, this paper proposes a plant-wide multi-period planning model for a real world refinery complex. All main plants, such as the refining plant, the lubricant oil plant and the utility plant etc., are integrated into a site model enabling the model to optimize operations among the plants at different periods and scenarios. Investment strategies and retrofitting suggestions are obtained which can contribute to an increase of the total profit by 6% in case studies. It has become common practice that electricity price is charged differently at different time shifts of a day in some countries. This paper proposes a multi-period model which examines how this pricing policy affects the operation of a refinery. Case studies show that adjusting the use of electricity to suit the price variance can significantly reduce operation costs in a refinery. Marginal Value Analysis (MVA), an analytical method that provides additional economic information for refinery complex, is also proposed in this paper. From the marginal value of final or intermediated products (e.g. electricity), important insights can be gained into the identification of production bottlenecks, decision-making and intermediate products pricing.