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.
