Experience and Qualifications that Produce Sustainable Results

Multi-Period Blend Optimization

As part of their efforts to drive operational efficiency, major refining companies are focusing more on managing supply-chain activities as an integrated process, with refinery planning and scheduling being the two areas that are becoming more closely connected. At the macro level, the best practices from leading global refiners in the planning and scheduling area include: enhancing crude selection process, optimizing three month production planning activities, establishing work processes to standardize crude and refinery scheduling, and achieving immediate value from blend optimization.


Refineries never operate in complete agreement with the monthly plan. Although a detailed weekly plan is closer to reality, crude slates can still change on a daily basis. Process units are run in blocked operation and product shipments are tendered in large batches to pipelines, waterborne transportation, and in smaller batches for tank-wagon and rail distribution. Calculating the effects of changing composition in the crude-charge tanks on crude-unit operation, downstream processing and blending requirements is key to the crude-scheduling work process. In leading refining organizations, this analysis is accomplished by using a day-to-day simulation of refinery operations.


This work process is critical to the daily operation; it provides the planners and schedulers with a projected look at future operations based on 30- to 45-day projected crude arrivals and product liftings. In many cases, refiners gear their projected crude scheduling and product lifting schedules out to 120 days. By projecting into the future they can obtain a more accurate view of the impact on operations and address events such as planned shutdowns and seasonal tank swings.

There are also several intangible benefits that can be achieved, including the improved coordination among blend operations, production and marketing, and the implementation of good and consistent blending procedures For each of the areas covered in the article, developing work processes based on practices from leading refiners will result in value gains. Beyond that, integrating these work processes through the planning and scheduling functions will result in even more significant value in areas such as:

 

  • Improving organizational collaboration
  • Operating the refinery closer to the economic plan
  • Improving planning model accuracy
  • Increasing supply chain velocity

Through integrated work processes and tools, planners and schedulers have the opportunity to work more collaboratively using the same models, data and language. Formulating decisions based on the same data and assumptions helps planners and schedulers make better decisions for the refinery as a whole, rather than for their specific organizations.