Recovery Boiler Advisor

Transcription

1 Recovery Boiler Advisor The Operator s Assistant For WCBLRBAC November 2018

2 RBA: How it works Mass Balances: from 15 seconds to 6 days Not just Leak detection: Blackout, Emissions, Dissolving Tanks, Sootblowers DCS data: only uses data in PI If it s not measured, RBA can t see it Information only: RBA doesn t control anything History: Can use playbacks to see past alarms

3 The Basics Overview Screen (each blr) Top left: mass balance in realtime. Top right: fire-side conditions Middle left: drum level readings Middle right: drum pressure Bottom two graphs: Next page

4 The Basics Overview Screen Title: Correction Purpose: show status of model Blue line is 0 for a brand new model at normal load. Deviations indicate model is old, or instrumentation has changed. This line moves when load changes, or as instruments drift. Yellow line is the amount of missing water. If yellow is above blue, RBA thinks there is a leak. If blue is above yellow, RBA thinks boiler is creating water.

5 The Basics Overview Screen Title: Balance Purpose: Show water balance for all time constants Blue line: Balance; If visible, water is missing. y-axis is the amount of missing water, relative to alarm limit. Ex: over the last 100 minutes, more water entered the boiler than steam, blowdown, and sootblow flow readings would predict. Users can mouse over either line to see the actual (not scaled) value Red line: Alarm limit; scaled to 1 The actual alarm limit gets much tighter on right side of x-axis Process upsets are expected to average out over time without leaks.

6 Balance Graph (enlarged)

7 The Basics Overview Screen (cont.) Title: Balance Purpose: Show water balance for all time constants Zones: think of them like erosion lines on a rock in a river These zones mark where the blue line has been Green is more common, red is less common Behavior: When the blue line crosses red, RBA alarms. Right side = small leak, can take hours to days to detect Left side = large leak, appearing suddenly If alarm appears for only 15-45s and then goes away, it was probably a header swing, etc. High zone number should raise suspicion if everything else seems normal

8 Alarms: Purpose: Display past alarms and messages Access: click on Message Summary button There is one for each boiler, on the overview page Can click on a message for details. Can right-click to get to a playback Playback simply shows RBA at the time of alarm

9 Alarms: (cont.) Purpose: Provide information on an alarm Start and end time of alarm displayed Location and size of leak (if known) Uses fire-side conditions to try to determine location Size is based on the amount of water missing vs. instrument accuracy.

10 Requirements for success Our program counts on decent instrumentation We can handle inaccurate instruments if consistent Good communication about unmeasured flows. steam vents/manual blowdown will cause false alarms. Can disable balance during manual blowdowns if operators are engaged Good communication about instrument recalibration/replacement Program required manual intervention when instruments change behavior

11 Features Excellent support via remote access Can re-tune model without down time Plugging trending Blackout and emissions monitoring Ability to suspend balance during unmeasured flows Handles load swings well Color bands add a layer of security

12 Installation logistics Program is installed on a computer on site, within the firewall I request remote access for support Historical data is used to make models, pulled from PI/OPC. Any computer on the same network can use a small interface program to view RBA. Always in control room, sometimes engineers want it

13 Questions, concerns? Colin Ruemmele, ChE Technical Advisor of Process Controls Buckman North America (317)