Enterprise-wide blend planning is useful in the optimization process of refinery operations. This type of planning requires integrated scheduling and planning to minimize the gap between the operations required for production scheduling and raw material procurement. Blending optimization is subject to many constraints. These model constraints are operational constraints – meaning limits of the equipment used, and quality constraints on volume and analyzers. This topic will discuss the blend planning process, gasoline blending, model constraints, optimization options, heel tracking, quality correlations, optimization algorithm, multi-product/multi-period planning, rollover planning, interfaces with other systems, enterprise-wide blend planning, blend short-term planning process, etc.