(167a) Using Process Historians to Detect Incidents


Process Historians have been used for many years to collect process data and sound alarms when needed to inform operators about potential problems. This paper will discuss approaches for utilizing process historians to detect reportable and recordable environmental incidents. These types of incidents may or may not be of immediate concern to operators, but of great interest to compliance managers. Thus, an incident reporting approach that relies on process historians to provide data extends the benefits of using historians beyond the realm of plant operations.

Typically, the data collected by Process Historian such as PI (OSIsoft), IP.21 (AspenTech), or PHD (Honeywell), is extracted from process instrumentation and controls using the concept of a ?tag.? Historian ?tags? provide a link between the data recording function in the historian and the process instrument that generates the data. Multiple ?tags? can be assigned to the same instrument to extract different data in cases where more than one type of data is available, such as an in-stream analyzer that collects chemical concentration for multiple chemicals.

When using Process Historians as a data collection point for incident detection, it is important to understand that the data to be collected by a ?tag? in the historian database will probably need to be evaluated for its significance in a separate system. That is because of the complex business logic that is generally required to detect reportable and recordable incidents based on a stream of data from the process. For example, a low temperature in a thermal oxidizer may indicate that an incident has occurred, but it may also indicate that the unit is out of service or in a maintenance mode. The incident reporting system must be able to connect to the historian database either continuously, or as often as needed to obtain and evaluate important data. It must also process the data that is collected and make the required notifications to compliance managers. Additional functionality, such as electronic reporting in a format that is acceptable to regulatory agencies, would also add value to the approach and reduce the time otherwise spent performing manual incident detection and reporting.

In summary, incident detection using a Process Historian relies on: (1) the capability to extract relevant (to incidents) data; (2) the ability to ?resolve? data in order to identify an incident has occurred; and (3) the functionality of your software to use historian-generated data in an efficient and effective incident reporting system. This paper will review current efforts by several chemical companies to achieve this objective using their Process Historians.