Customer : Saudi Aramco Customer : Saudi Aramco Technical Presentation on Technical Presentation on Fisher DVC6000-ESD Smart Fisher DVC6000-ESD Smart Positioners in Emergency Positioners in Emergency Shutdown ApplicationsShutdown Applications
Using Smart Positioners in Using Smart Positioners in Emergency Shutdown ApplicationsEmergency Shutdown Applications
Basic Concepts Historical methods Smart Positioners to the Rescue Installation Conclusion
What is a Safety Instrumented System?What is a Safety Instrumented System?
DefinitionDefinition
An SIS is a set of components such as sensors, An SIS is a set of components such as sensors, logic solvers, and final control elementslogic solvers, and final control elementsarranged for the purpose of taking the process arranged for the purpose of taking the process to a safe stateto a safe state when predetermined when predetermined conditions are violated.conditions are violated.
What is a Safety Instrumented System What is a Safety Instrumented System (SIS)?(SIS)?
(Hardware and Software)
Logic solver
Sensor Logic Solver Final ControlElement
What is a Safety Instrumented System What is a Safety Instrumented System (SIS)?(SIS)?
Dike Passive protection layer
Emergency response layerPlant andEmergency Response
ProcessValue Normal behaviour
BasicProcessControlSystem
Process control layer
Safety Through Layers of ProtectionSafety Through Layers of Protection
OperatorIntervention
Process control layer
Process alarm
ProcessShutdown
Trip level alarm
SafetyInstrumentedSystem
Safety layerEmergencyShut Down
Prevent
Mitigate
x x
Relief valve,Rupture disk Active protection layer
What is SIL?What is SIL?
SIL is a way of quantifying risk.
NO SIL
Ris
k
SIL1
SIL2
SIL3
SIL4
What Is SIL? – Safety Integrity LevelWhat Is SIL? – Safety Integrity Level
RISK
FrequencyConsequence
or
SIL Is Directly Related To RiskSIL Is Directly Related To Risk
Safety Integrity Level
SIL 4
SIL 3
SIL 2
SIL 1
Probability of failure on demand per year
(Demand mode of operation)
Risk Reduction Factor
>=10-5 to <10-4
>=10-4 to <10-3
>=10-3 to <10-2
>=10-2 to <10-1
100000 to 10000
10000 to 1000
1000 to 100
100 to 10
PFD 1/PFD
Safety Integrity LevelsSafety Integrity Levels
Valve50%
Sensor35%
Logic Solver
15%
What Components Cause More Faults?
SIS Faults – Investigation Uncovers SIS Faults – Investigation Uncovers CluesClues
(Hardware and Software)
Sensor
SIS Faults – Where Do They Happen?SIS Faults – Where Do They Happen?
Final ControlElement
Logic Solver
Typically operate in one position - only move upon an emergency
Without mechanical movement, unreliability inherently increases
Frequent testing ensures valve availability upon Demand
Historically, expensive, labor intensive pneumatic testing methods required
Why does the ESD valve account Why does the ESD valve account for 50% of failures?for 50% of failures?
Using Smart Positioners in Using Smart Positioners in Emergency Shutdown ApplicationsEmergency Shutdown Applications
Basic Concepts Historical methods Smart Positioners to the Rescue Installation Conclusion
Aramco Existing Pneumatic Test Aramco Existing Pneumatic Test Methods (costly and complicated)Methods (costly and complicated)
Limitations to existing pneumatic test Limitations to existing pneumatic test panelpanel
Local testing and Hard Stop Requires bypass Shutdown and Test Restricted analysis Expensive & Complex Limit Switch and time Signal to Allow Partial
Stroke
Using Smart Positioners in Using Smart Positioners in Emergency Shutdown ApplicationsEmergency Shutdown Applications
Basic Concepts Historical methods Smart Positioners to the Rescue Installation Conclusion
Smart Positioners to the Rescue-Smart Positioners to the Rescue-FeaturesFeatures
Partial Stroke Diagnostics Vent Actuator Pressure Collect pressure, travel data and analyze Supply and output pressure sensors Documentation (Compare and Storage) Full stroke valve signatures for seat load details
Smart Positioner or Digital Valve Controller (microprocessor-based instrument)
Smart Positioners to the Rescue-Smart Positioners to the Rescue-CapabilitiesCapabilities
Partial Stroke Test criteria– Configurable valve travel
– Valve returns to normal operation, if diagnostic fails
– If “valve is stuck”, alert operator
– Don’t exhaust all the air
– Configurable Speed of Stroke
– Demand Overrides Partial Stroke Test
Without partial valve stroke testing – Without partial valve stroke testing – SIL2SIL2
With partial valve stroke testing – With partial valve stroke testing – SIL3SIL3
Doing The MathDoing The Math
PFD avg = [(DF)(d) (TI/2)]p + [(DF)(d) (TI/2)]F
Assumptions: DF is 70% for partial stroke and 100% for full stroke
TI is 4x/yr for partial and 1x/3 yrs for full
Adding Partial Stroke Testing
Full Stroke Testing Only
PFD avg = [(DF)(d) (TI/2)]
Assumptions: DF is 100% and TI is 1x / yr
= (1) (d) (1/2) = 0.5 (d)
= [(0.7)(d) (0.25/2)] + [(1-0.7) (d) (3/2)]
= 0.09 (d) + 0.45 (d) = 0.54 (d)
Conclusion: Partial Stroke Testing enables extending the full-stroke testing interval to 3 years and still maintaining the same PFD!
Continuous Check of Device Integrity– In case of problem, provide alert
Smart Positioners to the Rescue -Smart Positioners to the Rescue -CapabilitiesCapabilities
Manual Initiation of Automated testing – Remote companion software
– Handheld
– Remote push button
On Demand, digital valve controller continues to communicate
Smart Positioners to the Rescue -Smart Positioners to the Rescue -CapabilitiesCapabilities
Step Response Test– Initiated via Companion software
– Provides analysis of overshoot, hysteresis, dead time and travel time.
– This data can be utilized to extrapolate valve stroking time
Modular
Construction
Smart Positioners to the Rescue -Smart Positioners to the Rescue -CapabilitiesCapabilities
Encapsulated & Potted electronics
Pneumatic relay - mechanical beam
Using Smart Positioners in Using Smart Positioners in Emergency Shutdown ApplicationsEmergency Shutdown Applications
Basic Concepts Historical methods Smart Positioners to the Rescue Installation Conclusion
Solution Proposal:Solution Proposal:Point to Point Mode ApproachPoint to Point Mode Approach
Digital Valve Controller
Travel Feedback
Logic Solver
24V DCSolenoid Valve
Exhaust
S
ESD Valve/Actuator
4-20 mA DC
Supply Pressure
Solution Proposal:Solution Proposal: Multi-drop Mode Approach Multi-drop Mode Approach
Digital Valve Controller
Travel Feedback
Logic Solver
24V DCSolenoid Valve
Exhaust
S
ESD Valve/Actuator
Supply Pressure
Line Conditioner
Using Smart Positioners in Using Smart Positioners in Emergency Shutdown ApplicationsEmergency Shutdown Applications
Basic Concepts Historical methods Smart Positioners to the Rescue Installation Conclusion
ConclusionConclusion Increased System Availability Safety Defaults Predictive Maintenance System Audit Documentation Valuable Time Saving Reduced Cost Of Ownership
Installed BaseInstalled BaseSaudi Aramco - Yanbu Saudi Aramco ShedgumSaudi Aramco, Berri Gas PlantSaudi Aramco, Haradh Gas Plant ICI - Runcore plant - UK Doffasco - Canada TiWest - Australia SCECO - Riyadh - S. Arabia Huntsman Chemicals-BeaumontDuPont-Washington Works- USADOW Chemicals, Freeport - USAQP (Qatar Petroleum) - Qatar ORC, OmanAnd more…
Using Smart Positioners in Using Smart Positioners in Emergency Shutdown Emergency Shutdown ApplicationsApplications
QUESTIONS?