Multi-product manufacturing takes place at refineries. Diesel, gasoline, aviation fuel, and many other products are produced because of continuous processes during refinery operations. A final refinery product is obtained by blending many intermediate products to achieve the desired quality, quantity, and schedule specifications. To meet the availability of quality products in sufficient quantity at the right time, planning, scheduling, and optimization are crucial. This topic will discuss component volume balance for all blend grades, limits imposed on the tank inventory by the planner, recipe constraints by the planner, equipment limits, blending constraints, component tank inventory restriction, volume balance of components, taking into account all in and outflows, etc.