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Show Figure 2 shows the informational flow for the GNOCIS implementation at Gaston. All process data is collected through the DCS and passed on to the GNOCIS host (a PC running WindowsNT) for calculation of the recommendations. These recommendations are then conveyed to the operator via the DCS operator displays. If acceptable, the operator can then implement these changes through the DCS operator displays. Also, th,e operator has the option of running GNOCIS closedloop in which the recommendations are automatically implemented. The primary operator display, which resides on the DCS, is shown in Figure 3. Open-Loop Operator Displays n Advise Current Operating Conditions Model Development A pprove d Setpoints .. - L&N MAX 1000 -- A~ ~ctuator Demands Closed-Loop GNOCIS ~ L&N MAX 1000 , . Data AcqUistlon Figure 2. Gaston I GNOCIS Installation Figure 3. Gaston/GNOCIS Operator Interface Plant --- Process Data Recommendation Based on Current Mill Configuration Recommendation Based on Best Mill Configuration Remove/Add Parameter from Optimization Consideration Data collected through the DCS was used to create the combustion models. Although in excess of 1000 pOints are being archived in the DCS, early in the project, a subset of approximately 100 parameters were identified as being possibly important for combustion modeling purposes. Modeling efforts have concentrated on the most recent three to four months of long-term data. Short-term tests were run periodically during which the unit was run at off-design conditions to augment data available from normal operation and thereby expand the range over which the combustion model could make estimates. Also, results from testing GNOCIS were generally included in the training data for future models. The collected data was preprocessed to remove invalid data and to some extent, data collected during transients. In general, the existing control system and instrumentation provided an excellent platform for the collection of real-time process data in a format usable by GNOCIS. 3 |