on-line optimisation of a refinery utilities plant
DESCRIPTION
TRANSCRIPT
On-line Optimisation of an On-line Optimisation of an Integrated Petrochemicals Integrated Petrochemicals FacilityFacility
Glyn Westlake, Emerson
Mark Brewer, Emerson
Tim Desmond, BP
[File Name or Event]Emerson Confidential27-Jun-01, Slide 2
OverviewOverviewOverviewOverview The Grangemouth site.
On-line optimisation.
– Types of optimisation.
– Why use optimisation here?
The implemented system.
[File Name or Event]Emerson Confidential27-Jun-01, Slide 3
BP GrangemouthBP GrangemouthBP GrangemouthBP Grangemouth Large integrated site.
Processing facilities for Forties pipeline system.
– Approx 1 million barrels per day.
Major Fuels Refinery.
– Annual capacity approx 10 million tonnes.
Major petrochemical producer.
– Annual capacity approx 1.2 million tonnes.
Large energy user.
– Steam.
– Electricity.
[File Name or Event]Emerson Confidential27-Jun-01, Slide 4
Grangemouth Utilities PlantGrangemouth Utilities PlantGrangemouth Utilities PlantGrangemouth Utilities Plant
8 Boilers.
7 Steam Turbines.
1 Gas Turbine/Heat Recovery Steam Generator.
– GT/HRSG run by separate company.
– Contracts for exchange of fuel/steam between BP and “CHP”.
[File Name or Event]Emerson Confidential27-Jun-01, Slide 5
Grangemouth Utilities PlantGrangemouth Utilities PlantGrangemouth Utilities PlantGrangemouth Utilities Plant
GT
Electricity Users
TA 5
EHP Steam Users
MP Steam Users
Fuel Gas
Fuel Oil
Natural Gas
Blr 8
Blr 9
Blr 10
Blr 11
Blr 12
Blr 13
Blr 14
Blr 15
TA 6
TA 7
TA 8
TA 9
TA 10
TA 11
Electricity Grid
Types of OptimiserTypes of OptimiserTypes of OptimiserTypes of Optimiser
PLANT
OPTIMISER
Off-Line
• Plant data entered manually.• Model tuned manually.• Results implemented manually.
PLANT
OPTIMISER
Open-Loop
• Plant data entered automatically.• Model tuned automatically.• Results implemented manually.
PLANT
OPTIMISER
Closed-Loop• Plant data entered automatically.• Model tuned automatically.• Results implemented automatically.
[File Name or Event]Emerson Confidential27-Jun-01, Slide 7
Real-Time Optimisation - CriteriaReal-Time Optimisation - CriteriaReal-Time Optimisation - CriteriaReal-Time Optimisation - Criteria
Problem complexity– Is “the answer” obvious?– Can the system be simulated?
Degrees of freedom– Is there any scope for optimisation?– Will the optimiser generate a large number of
small set point changes? Amount of change in the problem
– Can “the answer” be worked out once and then kept?
– Can the system cope with process disturbances?
[File Name or Event]Emerson Confidential27-Jun-01, Slide 8
Why Use Optimisation Here?Why Use Optimisation Here?Why Use Optimisation Here?Why Use Optimisation Here? Complexity
– Individual unit performance can be found from historic data.
– Units change performance gradually due to fouling etc.
– Optimal operation requires trade off between different units
Degrees of freedom
– Boiler rates.
– Turbine rates.
Change
– Steam demands.
– Indigenous fuel availability.
– Prices.
– Unit performance.
[File Name or Event]Emerson Confidential27-Jun-01, Slide 9
Why Use Optimisation Here?Why Use Optimisation Here?Why Use Optimisation Here?Why Use Optimisation Here? Site-wide push to reduce energy usage.
Desire to improve
– Instantaneous operation. How should we currently be running to minimise costs?
– Planning. What equipment configuration would be best during the expected plant start-up?
[File Name or Event]Emerson Confidential27-Jun-01, Slide 10
What does the optimiser do?What does the optimiser do?What does the optimiser do?What does the optimiser do?
For the given total steam and power demand:– Minimise total operating cost (including CHP
streams).
By– Choosing individual boiler steam generation rates.
– Choosing individual T/A electricity generation rates.
Project ComponentsProject ComponentsProject ComponentsProject Components
On-line Optimiser Off-line Optimiser
Control Room Offices
[File Name or Event]Emerson Confidential27-Jun-01, Slide 12
On-line/Off-line OptimiserOn-line/Off-line OptimiserOn-line/Off-line OptimiserOn-line/Off-line Optimiser On-line optimiser
– Results every few minutes displayed on DCS screens.
– Operators use the advice to set up the plant for best economic operation.
Off-line Optimiser– Uses same model as on-line optimiser, tuned to current
performance.
– Allows office based staff to run operating scenarios to evaluate alternatives.
– Automated comparison of different equipment configurations.
– Used by Optimisation Engineers/Planners/Technical Engineers.
– Intended for day by day use for short term planning.
[File Name or Event]Emerson Confidential27-Jun-01, Slide 13
System ComponentsSystem ComponentsSystem ComponentsSystem Components
DCS
Data Conditioning
EstimatorsOptimisersModels
Shared Data
[File Name or Event]Emerson Confidential27-Jun-01, Slide 14
Project Status/ConclusionProject Status/ConclusionProject Status/ConclusionProject Status/Conclusion
System successfully implemented.
Benefits audit ongoing.
On track to exceed guaranteed 1% benefits.
System intended to provide basis of closed-loop optimiser.
Good candidate for on-line optimisation.