From Basic Control to Optimized Systems-Applying Digital Control Systems to Steam Boilers

Abstract

This presentation examines the application of Distributed Digital Controls in order to review the application of this recent control technology towards Steam Boilers in a step-by-step manner.

The main purpose of a steam generating boiler is to supply enough steam to meet process demands. Steam conditions must remain as stable as possible, because variations in the steam system can affect downstream processes. Pressure variations in the steam supply header, for example, can have a severe effect on heat transferred to a process. If that process suffers an upset, unstable conditions can propagate from one process to another via the steam supply system.

The closer the tolerance in the boiler control system, the smaller the steam header disturbances will be. This reduces the interaction, or 'coupling', of upsets between steam-consuming processes. Also, it may reduce the complexity of instrumentation needed for those processes. If the boiler control system can eliminate major upsets, the downstream processes won't need exotic schemes to compensate for such upsets.