Tank Storage Istanbul 11/2010 LPG loading operations management
Automation & metering solutions
Agenda 1.
General configuration of an LPG depot
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Flow metering considerations and requirements
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Health & Safety requirements
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Loading authorization and security systems management
2.
Case study
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Presentation of an optimized supervisory and MECI automation and supervision system for the management of 14 LPG depots including 7 unmanned depots
Presentation – 09/11 - 2
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Automation & metering solutions
Flow meter requirements
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LPG transactional bulk transfers can be carried out using standard volume or mass.
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LPG Custody Transfer measurement primary meter must meet an accuracy of 0.6% (OIML R117 - MID)
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Measure Accuracy depends on maintaining a single phase liquid flow through the flow meters
Presentation – 09/11 - 3
Automation & metering solutions
Flow (volume and mass) metering • Volumetric flow metering (liters) • PD meter, turbine meter • Ultrasonic flow meter • Mass flow metering Coriolis (kg, tons)
Presentation – 09/11 - 4
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Automation & metering solutions
Flow (volume and mass) metering
Benefits
Disadvantages
• Primary measurement in volume (PD and turbine meters) • Primary measurement in mass (coriolis meters) • Lack of moving parts, no mechanical wear (coriolis)
• Liquid phase assurance: Pressure drop can cause vapor breakout (flash point) • Mechanical wear due to poor lubricity of LPG (PD and turbine meters) • Units conversion uncertainty problems (mass to volume, volume to mass) • Difficult calibration with volumetric devices (coriolis) • Vibration sensitivity (coriolis)
Presentation – 09/11 - 5
Automation & metering solutions
Volume conversion to Mass Conversion from mass to volume and calculation of standard volume require accurate knowledge of the properties of LPG mixtures.
Mass =Volume * Density Density must be determined ! 1- Using an on-line densitometer (expensive solution); the densitometer is directly connected to the flow computer 2- Using LPG conversion tables, 24E and 23E, (produced and published by The Gas Processors Association (GPA) under the designation TP25), or other standards. The electronic flow computer will convert the volume to standard volume V15 and will compute the transactionnal mass = V15 * D15
Presentation – 09/11 - 6
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Automation & metering solutions
Measurement by weighing full truck
Presentation – 09/11 - 7
Automation & metering solutions
Measurement by weighing full truck
Benefits
Disadvantages
• Primary measurement in mass • Vapor phase measurement unnecessary • Balance in weight easier • Easy weighting instruments calibration
• Very expensive solution (weighting bridges, on-board weighting sensors) • Tank trucks volume overfilling not controlled • Tank truck traffic in the loading terminal heavier, more complex supervision system • Safety problem; LPG gas retention on in weighting bridge installation gap Presentation – 09/11 - 8
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Automation & metering solutions
LPG flow meters operation requirements 1 - Loading arm and hose must be constantly full of product in service operation 2 - Liquid phase assurance; LPG gets a high Vapor Pressure. Pressure drop can cause flashing change to two phase conditions, which can distort the measure accuracy. LPG Vapor Pressure is a mathematical equation Antoine formula, Vapor Pressure in relative bar unit function of temperature: VP = exp(a-b/(c+t)))-1 Butane C4 H10 Propane C3 H8
a:9,6382297 a:8,8258087
b:2321,2682 b:1897,6525
c:256,64 c:262,79
Presentation – 09/11 - 9
Automation & metering solutions
LPG flow meter requirements Vaporization depends on temperature and pressure of measured product How to maintain pressure and avoid vaporisation and maintain the liquid phase ? – Cooling the temperature of the LPG (expensive) – Maintaining the LPG all over the pipe at a pressure higher than its own Vapor Pressure: • Holding constant pressure though P > LPG Vapor Pressure at max service temperature • Holding adjusted pressure though P > LPG Vapor Pressure + 1 bar (dynamic regulation)
Presentation – 09/11 - 10
5
Automation & metering solutions
Truck loading operation (1) LPG is pushed in the piping in order to:
Cooling process
¾ Push out gas pockets ¾ To cool the piping installation in order to avoid gas formation during loading operation
T° Ì
Storage
Presentation – 09/11 - 11
Automation & metering solutions
Truck loading operation (2) The required quantity is pumped under pressure and loaded into the tank truck. In some configuration, the gas phase in the tank is either condensed or returned to the LPG storage. The site system or the batch controller control : ¾The flow pressure regulation ¾The flow rate regulation
Storage
Presentation – 09/11 - 12
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Automation & metering solutions
Tank unloading operation (1) Gas phase of the storage is used to push out the liquid of the tank truck
Empty tank gas recovery Gas phase
Liquid phase
Storage
Presentation – 09/11 - 13
Automation & metering solutions
Tank unloading operation (2)
The direction of the compressor is inverted in order to recover the gas phase of the tank truck.
2)
Gas phase recycling
Gas
Storage
Presentation – 09/11 - 14
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Automation & metering solutions
H&S requirements - Overall LPG site
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General site gas, flame and smoke detections (emergency alarms)
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Synchronization of the valves and pump status (emergency shut down valves)
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Over & under pressure sensors
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Overflow probes
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Tanks level control Presentation – 09/11 - 15
Automation & metering solutions
H&S requirements - LPG loading position
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Loading arm safety break
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Loading arm settled valve
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Loading arm pressure switch
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Vehicle grounding system
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Overfilling detection sensors
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Dead-man control
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Metering defaults
Presentation – 09/11 - 16
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Automation & metering solutions
H&S requirements - operator cabinet Truck overfilling sensor: In addition to visual rotating gauge, tank truck can be equipped of an overfilling sensor (optical, magnetic , radar) The safety control system automatically stops the filling process when the overfilling level is reached
Dead Man safety device: At a regular time interval, the operator must manifest its presence on the site actuating the dead - man device. In case of non presence action, a sound alarm is actuated. If the situation last, the general safety alarm is actuated for the site safety and alarm to safety services
Earthing connection; A specific grounding control device does not allow loading operation if not connected
Presentation – 09/11 - 17
Case study : Optimization of metering, automation and supervisory for LPG depots
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Overview
Final user
A French Major Oil Company
Location
France
Application -Supervision and automation of 15 butane, propane & LPG depots including 7 unmanned facilities (without permanent employee) -Automation of loading & unloading of LPG, butane, propane local and distant tank farm supervision, remote maintenance Presentation – 09/11 - 19
Automation & metering solutions
2-Case study : Automation of loading & unloading stations Overview Headquarters Main depots Unmanned depots
Presentation – 09/11 - 20
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Overview
Headquarters
Remote maintenance Possibility to control all the depots Stock reconciliation in mass
Main depots
150 à 500 m3 Supplied by rail or tank trucks
Unmanned depots 100 m3 maxi Supplied by tank trucks Controlled by related main depot
Presentation – 09/11 - 21
Automation & metering solutions
2-Case study : Automation of loading & unloading stations Overview: unmanned depot Access control for trucks and drivers
Operator cabinet
Unloading area Loading area
Operator cabinet
Presentation – 09/11 - 22
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Depot access control
Driver identification
Biometric identification at the inlet of the depot Fingerprint readers are used to allow only accredited drivers to enter the facility
Presentation – 09/11 - 23
Automation & metering solutions
2-Case study : Automation of loading & unloading stations Depot access control
Trucks identification at the inlet of the depot
Semi passive tag technology
Microwave based communication The tag echoes its identification code when receiving a 2.45 GHz carrier emitted by the antenna
Hand free detection
Presentation – 09/11 - 24
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Loading operations : operating procedure
The driver is identified via a smart card reader
The driver key-in loading data via MMI - mass preset value and medium - Actual tank filling rate -Truck plate number
The system calculates and display the maximum allowed quantity to be loaded The driver must then connect security devices (grounding system, tank level switch) He will then be allowed to press the “Dead-man” & the “Start loading” buttons Presentation – 09/11 - 25
Automation & metering solutions
2-Case study : Automation of loading & unloading stations Loading operation : operator cabinet
Total mass display
Emergency stop button Tank truck level detection
Grounding detection
Card reader Man – Machine Interface “Start loading” button
Dead-man detection
Presentation – 09/11 - 26
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Metering systems
1-Measuring system with turbine meter -Measurement of volume at operating pressure & temperature -Measurements of operating pressure and temperature -Calculation of operating density from P, T & API MPMS 11.2.2.M table -Calculation of masse Advantage:
Easy to calibrate (volume against ball prover, P, t)
Weak point:
Not a direct mass measurement Can lead to error if product quality is not constant
Presentation – 09/11 - 27
Automation & metering solutions
2-Case study : Automation of loading & unloading stations Metering systems : ball prover calibration
Presentation – 09/11 - 28
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Metering systems
2-Measuring system with massflowmeter
Advantage:
Direct measurement of mass No need for P & T custody transfer approved measurements
Weak point:
Calibration against prover needs also measurement of reference density
Presentation – 09/11 - 29
Automation & metering solutions
2-Case study : Automation of loading & unloading stations Metering system: typical mass metering skid
Massmeter converter Massmeter transducer
Motor valve Control valve for line pressure adjustment
Presentation – 09/11 - 30
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Metering systems : flow computer (FC) functionalities
1-Calculation of loaded quantities, batch control, transactions data storage,
2-Blending control for LPG preparation The driver enter the quantity of LPG to be loaded The FC calculates the quantities of butane and propane to be loaded The batches of butane and propane are loaded successively
3-Communication
Presentation – 09/11 - 31
Automation & metering solutions
2-Case study : Automation of loading & unloading stations Metering systems : flow computer functionalities
4-Additive injection control Injection of ethyl mercaptan for odour or of proprietary compounds for road fuels
5-Line pressure control The FC calculates the saturation pressure of LPG from P & T measurements It defines a pressure set point (Psat + 1 bar) controlled by control valve
6-Calibration operation management
Presentation – 09/11 - 32
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations Automation and supervisory system functionalities
1-Automation of loading and unloading operations Management of loading/unloading cycles Loading authorization according to company quotas Security devices management
2-Communication with the truck driver Operating instructions, error and warning messages
3-Communication with headquarters and dispatching
Presentation – 09/11 - 33
Automation & metering solutions
2-Case study : Automation of loading & unloading stations System architecture for main depot Supervisory PC and data base
Remote maintenance PSTN
Printer
Printer Bill of lading
PLC Truck indentification
Badge reader
Printer events Fingerprint reader Sécurity dev.
Presentation – 09/11 - 34
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Automation & metering solutions
2-Case study : Automation of loading & unloading stations System architecture
Presentation – 09/11 - 35
Automation & metering solutions
Thank you for your attention, Q & A ????
Presentation – 09/11 - 36
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