Previously, plant performance assessment and diagnosis have considered only chemical process measurements (flow, level, pressure, temperature, composition).
Moreover, the tag lists presented for analysis generally are contained within a restricted plant envelope. There are, however, several influences which cross the boundary of the plant envelope including feed and product flows and the site utilities (steam, water, electricity, fuel gas). These feed and product flows and site utilities are the primary medium by which disturbances in one plant in a site can upset another plant.
While the influence of feed and product streams is localized and fairly easy to diagnose, there are many unexplored issues when disturbances propagate via site utilities. This is especially problematical when the utility is the electrical system because voltage dips and transients due to switching of heavy current loads in one location may instantly upset equipment in a remote part of the site. Case studies are under way to show how measurements from electricity, steam, water, and fuel gas utilities should be included, analyzed and interpreted in a site-wide system.
Development of wireless communication standards for use in process applications is having an impact on machinery condition monitoring. Field devices can now send data back continuously to the central control room via wireless signals.
Thus a great deal more information is starting to become available in the control room making it much more feasible to integrate condition monitoring. Measurements such as vibration, alignment, infra-red thermography, oil analysis, acoustic or ultrasonic analysis can now be lined up with process data and event data such as operator actions or alarms for better plant performance assessment and diagnosis.
- Cecilio, I.M., Chen, S-L., and Thornhill, N.F., 2011, Importance of auxiliary systems for process fault detection and diagnosis, 19th IEEE Mediterranean Conference on Control and Automation (MED’11), Corfu, Greece, June 20-23, 952-957.