OVERVIEW

Before the start of an operating period, usually a month, the planner submits an operating plan, termed the definitive operating plan (DOP), to the refinery Operations Department, defining how the refinery is to be run during the month.

The DOP for a given month contains information on the following:

1. The crude oils to be processed during the month and their quantities.

2. Product grades and the quantities to be produced during the month.

3. Intermediate stocks to be drawn from the inventory to make the refinery s product slate.

4. Inventory of intermediate stocks to be built up during the month.

5. Process unit capacities available, based on the refinery s latest shutdown schedule and estimated process unit capacities utilized to make the product slate.

6. Composition of feed to all conversion units.

7. Product prices of the balancing-grade products and energy price used to optimize product blending.

8. Blending instructions for critical stocks, where alternate blending is possible.

9. Additives to be used for blending products and their estimated consumption. Only additives used for product blending (for example, dyes for gasoline, antistatic and anti-icing additives for jet fuels, pour point depressants for diesels) must be listed.

10. Expected production rate for all product groups during the month.

The DOP is prepared using a refinery linear programming model. Refinery material balance spreadsheet programs can also be used, but LP models are preferred as no product blending optimization is possible with spreadsheet programs. The first step in preparing the...