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Reevaluating Advanced Control of the Ammonia Process JAMES GREMILLION
Emerson Process Management
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 2
The beginnings of Digital Control
1964 IBM 1800 Process Control
Computer Developed
1966 IBM 1800 controls the Borden
Ammonia Plant
1969 Control results in a 2-4%
increase
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 3
0
10
20
30
40
50
60
70
1955 1965 1975 1985 1995 2005 2015
Ammonia Production Efficiency
Gigajoules/Metric Ton Thermodynamic Limit
Production Efficiency Over the Years
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 4
Jupiter Ammon
Sal Ammoniac
Ammonia Plant
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 5
The Ammonia Plant at Jupiter Ammon
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 6
The Ammonia Plant at Jupiter Ammon
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 7
Water-to-Feed Ratio Reaches an Optimum
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 8
Fire-to-Feed Ratio Reaches a Constraint
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 9
A Well-Behaved Loop
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 10
The Process Control Loop
Two-thirds of control loops dont perform and some even make the situation worse
IFAC
In that control loops ultimately carry out most business decisions made in a refinery, chemical plant, paper mill, or power plant, its very alarming that two-thirds of all control loops perform in a disruptive or ineffective manner.
Industrial Computing
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 11
The Causes of Variability in Control
Valve Problems
Controller Tuning Problems
Transmitter Problems
Interactions
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 12
An Example of Control Loops Interacting
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 13
A Matrix Controller Reduces Interaction
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 14
Reducing Variability -Closer to Optimum
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 15
Closer to Optimum = More Production
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 16
Reducing Variability -Closer to Constraint
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 17
Closer to Constraint = More Production
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 18
The Causes of Variability in Control
Valve Problems
Controller Tuning Problems
Transmitter Problems
Interactions
80-90%
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 19
The Process Control Loop
Two-thirds of control loops dont perform and some even make the situation worse
In that control loops ultimately carry out most business decisions made in a refinery, chemical plant, paper mill, or power plant, its very alarming that two-thirds of all control loops perform in a disruptive or ineffective manner.
Industrial Computing
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 20
A Well-Behaved Loop
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 21
An Example of a Problem
PUMP
MAINTENANCE
INSTRUMENTATION
MAINTENANCE
SYSTEM
INTERACTION
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 22
A Never-Ending Process!
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 23
Modern DCS have the tools for basic loop problem management
Loops in Manual Loops not in Cascade Loops Oscillating
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 24
Control Performance Consultant
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 25
Entech Toolkit Analyze Functions
Time Series Plots Auto-Correlation Power Spectrum Analyses Integrated Power Spectrum Cross-Correlation Histogram Statistical Data (mean, 2-Sigma, % 2-Sigma) Power Spectrum Peak Picking and many other functions
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 26
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 27
Get the 80%!
Valve Problems
Controller Tuning Problems
Transmitter Problems
Interactions
80-90%
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 28
Control Performance Consultant
Two to Five Days
Find the worst-offenders amongst interactions and fix them through advanced tuning techniques or by using a matrix controller (APC)
Demonstrate techniques and document results
[File Name or Event] Emerson Confidential 27-Jun-01, Slide 29
A Never-Ending Process!
Continuous, Never-Ending Effort
Continuous, Never-Ending Benefit