Transcript Computer-aided HAZOP

Computer-aided Hazard
Identification
Paul Chung ([email protected])
Department of Computer Science
Hazards and Operability
(HAZOP) Studies
• Established and widely used technique
in the process industry for hazard
identification
• Time consuming, labour intensive
process:
– Tedious
– Expensive
Computer-aided HAZOP
• Different levels of support:
– Electronic report form
– Electronic data (on plant, on fluids, etc.)
– Automated Hazard Identification
• Continuous operation
• Batch operation
Automated Hazard
Identification
• Continuous operation
– From basic research to commercial product – HAZID
– Basic technology
• Signed directed graph (SDG) representation
• Fault propagation
– Go through a list of deviations systematically and
identify the faults that cause the deviations and the
consequences that result from the faults and
deviations
HAZID Overview
• Automated extraction of plant design from a
CAD system, e.g. Intergraph SmartPlant P&ID
• Convenient forms for adding any missing
process specific information
• Tick boxes for selecting analysis options:
– Deviations, e.g. more flow, less flow, etc.
– Items to HAZOP, etc.
HAZID Overview
• HAZOP style output in different output
formats
– XML, with HTML web page view.
– Excel spreadsheet.
• Query facility for viewing analysis results
– e.g. viewing faults and consequences relating to a
particular plant item
– e.g. viewing the propagation path between a
particular fault and consequence
• Compare facility for viewing the difference
between two HAZID runs
– Useful for after making a change to the design
7
Hazid Operation
Select SP P+ID
From SmartPlant
Run Hazid data wizard,
Extract plant data from
SP database:
*Plant Items
*Piping, valves, fittings
*Controls
*Fluids information:
Temperature
Pressure
Fluid name
Hazid maps SP icons
to Hazop “Process”
models
Converts P+I diagram
to Analysis model
Hazid analyses plant and
generates Hazop Report
7
Hazid Operation
Select SP P+ID
From SmartPlant
Run Hazid data wizard,
Extract plant data from
SP database:
*Plant Items
*Piping, valves, fittings
*Controls
*Fluids information:
Temperature
Pressure
Fluid name
Hazid maps SP icons
to Hazop “Process”
models
Converts P+I diagram
to Analysis model
Hazid analyses plant and
generates Hazop Report
7
Hazid Operation
Select SP P+ID
From SmartPlant
Run Hazid data wizard,
Extract plant data from
SP database:
*Plant Items
*Piping, valves, fittings
*Controls
*Fluids information:
Temperature
Pressure
Fluid name
Hazid maps SP icons
to Hazop “Process”
models
Converts P+I diagram
to Analysis model
Hazid analyses plant and
generates Hazop Report
7
Hazid Operation
Select SP P+ID
From SmartPlant
Run Hazid data wizard,
Extract plant data from
SP database:
*Plant Items
*Piping, valves, fittings
*Controls
*Fluids information:
Temperature
Pressure
Fluid name
Hazid maps SP icons
to Hazop “Process”
models
Converts P+I diagram
to Analysis model
Hazid analyses plant and
generates Hazop Report
8
Mapping SmartPlant to Hazid models
SmartPlant
Database
References
Mapping created by user
for all company,
then mapping is >95%
automatic
Automatic mapping by Hazid:
Hazid Model
Types
=
=
Centrifugal Pump
=
?????
Mixer
Stripper
Absorber
Reactor
Valve
User makes choice
**This User mapping is required only once for the whole Project**
9
Checking Automatic Nozzle Mapping
Hazid model is process function:
But P+ID is piping:
N4
Vapour Out
Port
Vapour/Liquid
In Port
Vapour
N1
N3
Liquid
Liquid Out
Port
N5
N2
User confirms nozzle functions:
N1 is vapour/liquid in port,
N2 and N3 are liquid out ports,
N4 is a vapour out port
N5 is Cleanout liquid in port.
7
Hazid Operation
Select SP P+ID
From SmartPlant
Run Hazid data wizard,
Extract plant data from
SP database:
*Plant Items
*Piping, valves, fittings
*Controls
*Fluids information:
Temperature
Pressure
Fluid name
Hazid maps SP icons
to Hazop “Process”
models
Converts P+I diagram
to Analysis model
Hazid analyses plant and
generates Hazop Report
Equipment Knowledge Base
Knowledge about behaviour of equipment
Interaction between Faults, Deviations and Consequences
Consequence
Fault
These links are called
“arcs” in Hazid
Deviation
Fault
- can cause Consequence
Fault
- can cause Deviation to process variable
Deviation – can cause another Deviation
Deviation – can cause Consequence
Equipment Knowledge Base
Knowledge about Faults and Consequences
This is mainly engineering knowledge and experience
Out
In
Fault – Bearing failure
Consequences
•Casing damage
•Seal damage and leakage
•Loss of discharge pressure
•Flow disturbance
•Pump stops
7
Hazid Operation
Select SP P+ID
From SmartPlant
Run Hazid data wizard,
Extract plant data from
SP database:
*Plant Items
*Piping, valves, fittings
*Controls
*Fluids information:
Temperature
Pressure
Fluid name
Hazid maps SP icons
to Hazop “Process”
models
Converts P+I diagram
to Analysis model
Hazid analyses plant and
generates Hazop Report
HAZOP Style Output from
HAZID
HAZID Viewer Queries
• Standard format questions:
– What causes could there be for a selected
hazard?
– What consequences are there for a given
failure mode?
– How is a given hazard realised?
• Show a path of deviations for propagation
– Display all hazards with a given severity
rank or higher
Filtered Output showing Fault
Paths for a given Hazard
Automated Batch Plant
Hazard Identification
• Batch operation
– Early research prototype (CHECKOP)
– Basic technology
• Action representation
• State-based simulation
– Go through a set of operation instructions
systematically and identify potential ambiguities,
operating problems and hazards
– Applying guidewords such as before, after, no
action, etc.
CHECKOP System Overview
Simple Batch Reactor
Example
CHECKOP Plant Description
instance(tank101 isa tank, [content info [reactantA],
outports info [out is [pump101,in]]]).
instance(pump101 isa pump, [status is offline, outports
info [out is [valve101,in]]]).
instance(valve101 isa valve, [status is closed, outports
info [out is [reactor101, in2]]]).
instance(reactor101 isa stirred_tank_reactor, [
outports info [out1 is [valve103,in], out2 is [valve106,in]],
heatSink info [hout is [jacket101,hin]],
reaction info [reaction_ab_p]
]).
Operating instruction format
• Natural language
– Easy for user
– Requires natural language processing
– Could be ambiguous
• Structured template
– Easy for computer to process
– Limited expressive power
Operating instruction format
• Object Action
– valve101 open
• Object Action until Condition
– mixer on until elapsed-time 20 minute
• Object1 Action Object2 Filler-word Fluid
until Condition
– reactor101 fill-from tank101 with reactantA
until volume 30 percent
CHECKOP Operating
Procedure Input
charge reactor101 with reactantA: {
(1) valve101 open
(2) pump101 start
(3) reactor101 fill_from tank101 with
reactantA until volume 30 percent
(4) pump101 stop
(5) valve101 close
}
etc…
Deviation Generation
• Combine each single action in the procedure
with guide words, from:
– No action – Simple omission.
– Early/Late action – Sequence of procedure
changed (how many steps feasible?).
– Early/Late action termination – “until” condition of
action varied.
• Then, simulate the effect of executing the
new procedure on the plant, detect hazards.
Batch HAZOP Output
Operation
Keyword
(3)
No action
reactor101
fill from
tank101 with
reactantA
Early action
until volume
(-2)
30 percent
Late action
(+3)
Consequences
(6) agitator running while vessel empty
(17) cannot empty [reactantA, productP]
from reactor101 to tank103 because
content of reactor is [reactantB].
reactor101 cannot be filled from tank101
because there is no flow path.
reactor101 cannot be filled from tank101
because there is no flow path.
Batch HAZOP Output
Operation
Keyword
Consequences
(3)
reactor101
fill from
tank101 with
reactantA
until volume
30 percent
Early
termination
(to only 10
percent)
no consequence.
Late
termination
(to 50
percent)
(17) cannot empty [reactantA, productP]
from reactor101 to tank103 because
content of reactor is [reactantA, productP].
(17) contamination in tank103.
Future Work on CHECKOP
• A formal structured language for operating
instructions
• More guide words
– “Other” Action – change other variables of the
Action model
• Rules for reasonable deviations
– What are the most likely mistakes in operation?
• Integrate with HAZID
– HAZID is strong on process hazards, CHECKOP
better for operating errors, etc.
– HAZOP of start-up, shutdown, maintenance, etc.
Conclusions
• Automated hazard identification
– continuous operation
• commercial tool that can reduce the time of HAZOP
– batch operation
• promising area of research and development for
identifying problems associated with human errors and
operating procedures
• Benefits:
– Doing HAZOP earlier, and on modifications.
– Consistent, repeatable, complete hazard
identification method.
Acknowledgements
• The work described in this presentation
is being funded by
– HAZID Technologies Ltd
– Engineering and Physical Sciences
Research Council, UK
• Thanks are also due to my colleagues
– Dr Steve McCoy
– Mr Dingfeng Zhou