Design for Online Process and Blend Scheduling Optimization

In manufacturing with transformation of natural resources into products, different quality raw materials varying in composition are segregated, stocked and blended in order to prepare the bulk feed quality of the plant. In such blend scheduling problem, the topology of the storage and blend operations as well as the process design network can affect the performance of the scheduling production of the intermediate streams and final products. The capacity of responding to feed quality demands to fulfill the current plant needs for improved scheduling (in a real-time updating of the plant) should be considered in the design. Considering the present move in industry toward online scheduling cycles, we discuss the design aspects for improved blending and processing of compositional-level raw materials found in the petroleum (fractional), petrochemical (molecular) and metallurgic (atomic) industries. The needs of diverse quality feed of the plant can vary continually considering a highly dynamic market demand variation of products to be made or even an abrupt process change to be mitigated by immediate feed quality modification. Hence, the detailed design of the blend scheduling and processing units must be constructed in direction to high-performance operations considering flexibility, responsiveness, management ability, etc., as we shall demonstrate with the examples. We compare computational efforts and resulted products in the preparing of a feed to be processed using continuous blending and considering batch mixtures between the storage and feed tanks (for liquids) or stockpiles (of solid materials). An example of process design for separation in towers in cascade in the crude-oil refining is highlighted as well. Although the problem focuses on the design for raw material- or feed-edge blend scheduling operation into online perspectives, the same analyses are valid for the product-edge.