Steam headers on an industrial site typically consist of long pipe runs connecting boilers, turbines, heat recovery steam generators (HRSGs), and process equipment. In many cases, control functionality to manage these headers as a system is not present and there is no direct control link between the users of the Btu (processes) and the Btu input devices (boilers and/or HRSGs). Since headers in an industrial environment are subject to localized header pressure changes and equalization delays, a system that is managed strictly with local pressure control can equalize at a state that is not cost optimal. In addition, during upset conditions or in the event of equipment trip, extensive manual intervention is often required to ensure that a single issue does not cascade into a total powerhouse shutdown.
Solution: The most cost effective electrical/steam balance can be obtained in normal operation and cascade trip events can be eliminated during upset conditions if the steam distribution system is coordinated and controlled as a unit. To achieve this, all header pressure management devices such as pressure reducing valves (PRVs) and turbine valves must be coordinated by a dedicated real-time automation strategy. Emerson’s SmartProcess® Header solution optimizes utility costs and limits the negative effects of large upset events. This is achieved by minimizing header pressure disturbances, maximizing efficient generation by limiting the use of PRVs, prioritization of headers, and elimination of operator intervention during upsets and demand swings. When major equipment issues such as a boiler or turbine trip occur, SmartProcess Header assists by immediately and automatically rebalancing the steam system. Operations personnel can focus on the initial process issue, rather than the further problems such as cascading trips that it might cause.