Download GGS Operating Manual Vol 1 PDF

TitleGGS Operating Manual Vol 1
TagsGasoline Petroleum Diesel Engine Liquefied Petroleum Gas Barrel (Unit)
File Size9.1 MB
Total Pages275
Table of Contents
                            Section 1: A general introduction of the facilities
Section 2: HSE aspects
Section 3: Equipment Specification
Section 4: Process and Control Description
Sections 5 & 6: Electrical, Instrumentation and Emergency shutdown (ESD)
Section 7: F&G systems
Section 8: Telecom
Sections 9, 10 and 11: Product Specification, Pre-Requisites for Start-up and Start-up procedures for Utilities.
Sections 12, 13 and 14: Plant Start-up, Normal Operating & Monitoring and Plant Start-up after Emergency Shutdown.
Section 15 & 16: Troubleshooting Operations and Shutdown procedures.
The Annexure Section contains Plot plan, PFD, Heat and Material balance, Alarms & Trip schedule, Cause & Effect diagram, Utility summary and Vendor Operation Manual references.
Hazop Action No. 30
Special precautions need to be taken on Vessels like Production Separator prior to releasing them to Maintenance/Turnaround Inspection. Even though H2S content is less than 100 ppm there will be considerable accumulation of pyrophoric scale over a prolonged period of operation. The pyrophoric dust will catch fire when it is exposed to atmosphere. Before opening the Vessel, the Separator shall be dampened from a water source. Disposal of the pyrophoric dust/scale shall be as per Company procedure for disposal of hazardous waste and shall not be dumped in Plant areas which will lead to fire accidents. Pyrophoric fire prevention measures are to be put in place (including availability of relevant portable fire extinguishers)
Hazop Action No. 67
Handling and disposal of Contaminated filter Cartridges / Coalescer elements should be done in a safe manner. As these filters contain hazardous sulphur and nitrogen compounds this should be collected and disposed in designated storage areas. Proper PPE’s precautions to all personnel involved in handling the contaminated equipments to waste storage area.
When releasing Condensate/Produced Water Storage tanks, Condensate pumps/Filters, proper safety precautions are to be taken as per PTW Procedures and for vessel entry by Personnel. Check for Oxygen/Toxic HC components. The vessels are damped from a water source to avoid pyrophoric iron fires. Naturally Occurring Radioactive Material (NORM) and Low Specific Activity (LSA) Scale can appear during the drilling and process phases of Oil and Gas exploration and tend to deposit along with other scale. Low Specific Activity scale (LSA) which are found adhering to pipe and equipment internals produce potential radiation illness mainly due to Radium-226 produced from the decay of naturally occurring Uranium-238. Hence Radioactive Detection and PPE’s for protection against potential radiation illness should be used. The waste removed from Condensate storage/Produced water storage tanks/cartridge filter should be disposed off at locations specifically marked/designated as Waste holdup/storage area. The Waste disposal area shall be clearly fenced, marked and identified with safety tags/boards indicating warnings/dangers due to radioactive substances.
Personnel involved in the operation should wear Breathing Apparatus (BA) sets
Flange is broken and hydrocarbon concentration measured
Purging using N2 continues, as necessary
When hydrocarbon concentration drops below 10 ppm, the ‘All Clear’ is given and normal work activities can recommence
Hazop Action No. 758
The operator will be alerted at 80.6 barg by Low pressure alarm 305-PAL-3009 and should take immediate action to identify the cause and close 305-PV-3024
High flow alarm in the Flare Header by 331-FAH-5126.
The bigger control valve 305-PV-3009A closes fully and the pressure is controlled only by smaller control valve 305-PV-3009B
Hazop Action No. 67
Avoiding exposure to potential hazards during operations
Minimising the potential (frequency) for hazardous occurrences (release of hydrocarbons, hydrocarbon flammable gases and any other abnormal hazardous events)
Containing and minimising the consequence of the hazards (fire, explosion and toxic gas releases)
Providing the means of escape and evacuation from such hazards
Proving a safe working environment for Plant personnel
Area around the specific area is taped off to prevent personnel approaching the worksite
Personnel carrying out this operation shall take Work Permit, be aware of the hazards associated with nitrogen (N2), Carbon di-oxide (CO2) and H2S and wear appropriate Personal Protective Equipment (PPE)
As far as possible, the system to be entered is purged using N2/water dampening prior to opening. This also negates the threat of elemental sulphur and associated corrosion and cracking.
Hazop Action No. 30
Special precautions need to be taken on Vessels like Production Separator prior to releasing them to Maintenance/Turnaround Inspection. Even though H2S content is less than 100 ppm there will be considerable accumulation of pyrophoric scale over a prolonged period of operation. The pyrophoric dust will catch fire when it is exposed to atmosphere. Before opening the Vessel, the Separator shall be dampened from a water source. Disposal of the pyrophoric dust/scale shall be as per Company procedure for disposal of hazardous waste and shall not be dumped in Plant areas which will lead to fire accidents. Pyrophoric fire prevention measures are to be put in place (including availability of relevant portable fire extinguishers)
Hazop Action No. 67
Handling and disposal of Contaminated filter Cartridges / Coalescer elements should be done in a safe manner. As these filters contain hazardous sulphur and nitrogen compounds this should be collected and disposed in designated storage areas. Proper PPEs as given in Section 2.3 and precautions to all personnel involved in handling the contaminated equipments to waste storage area.
HAZARDS OF RADIOACTIVE MATERIAL
Liquid must be separated from gas in a primary separating section
Gas velocity must be lowered to allow liquids to drop out
Gas must be scrubbed through an efficient demister
Water and oil must be diverted to a turbulence-free section of the vessel
Liquids must be retained in the vessel long enough to allow separation
The water–oil interface must be maintained
Water and oil must be removed from the vessel at their respective outlets
Motor Bearings
Gearbox
Compressor (DE & NDE) bearings
Static pressure at the inlet and outlet of compressor: 304-PT-1221 and 304‑PT‑1232
Temperature at the inlet and outlet of compressor: 304-TT-1222 and 304-TT-1231
Flow into the compressor: 304-FT-1220
The various modes of the anti-surge controller are listed below:
In normal operation, the anti-surge controller is in AUTO
During compressor start-up and shutdown sequence, the controller is forced in ‘SEQUENCE’ and the anti-surge valve opens
The anti-surge controller can be manually operated to open or close the anti-surge valve from the UCP HMI (Human-Machine Interface). However, if the compressor operating point approaches the anti-surge control line, the controller is switched back to Auto mode automatically.
DCS set point is written to the Controller (DCS shall ‘track’ the controller set point when in ‘local’). The controller shall send the set point, as an analog value, back to the DCS for display of ‘set point’ on the DCS Controller faceplate.
Controller can be switched from AUTO to MANUAL, by sending a pulsed command from DCS to UCP. The controller shall send a confirmatory pulse back to the DCS for display of ‘AUTO/MANUAL’ on the DCS faceplate.
In MANUAL, the output of the valve can be manipulated from the DCS. The DCS requested valve position, which is an analog signal, is written to the controller. The controller shall send the valve position, as an analog value, back to the DCS for display of ‘valve position’ on the DCS faceplate.
In normal operation, the suction pressure controller is in Auto, the discharge pressure over-ride controller shall be in Track.
During Compressor start-up and shutdown sequence, the Suction Pressure Controller is forced in ‘SEQUENCE’.
The Suction Pressure Controller can be manually operated to increase or decrease the compressor speed from the UCP HMI and the DCS. However, switching from Auto to Manual is only possible when the controller is in Auto and not in Track.
Primary seal vent pressure NDE – Low-Low
Primary seal vent pressure NDE – High-High
Primary seal vent pressure DE – Low-Low
Primary seal vent pressure DE – High-High
ESD1 (trip with blowdown)
ESD button compressor skid
ESD button on UCP (unit control panel)
UCP critical failure
Plant in Early Operation (HP) mode
Both condensate pumps 302-P-001 A and B are stopped
Plant in ‘Normal Operation’ (LP) Mode
Both condensate pumps 302-P-002A and B are ‘Stopped’
TEG Vent Gas KO Drum 305-V-003
Produced Water Tank Off-gas
provided with a UV scanner for detecting flame of Pilot burner, and
provided with a redundant self-checking UV scanner for detecting flame of Main burner
Running status
Shutdown alarm
Common alarm
Feed Air supply
Membrane nitrogen Generation Section
Product gas
Common alarm
Heater running
High oxygen alarm
High differential pressure alarm
Heater outlet gas temperature high and low
Common fault alarm
Running indication
Blanketing of various process tanks and vessels
Flares as pilot and purge gas
Stripping gas for TEG regeneration
Fuel Gas for TEG regeneration
Fuel in TEG incinerator and direct fired heater
Based on a load of 9.367 MW
331-LIC-5110 output sets the output of 331-P-001A/B Duty Booster Pump Motor- control-block to 1 i.e. ‘Start’ command for the Duty Booster Pump of 331-P-001A is sent to PMS over the serial link.
In case still the level 331-LI-5100 doesn’t reset below the High control set point within ‘xx’ minutes (configurable) after the Duty Booster Pump-A has started, the Standby Booster Pump-B will automatically start and the Duty Booster Pump-A shall be stopped, i.e. 33-LIC-5100 output sets the output of 331-P-001A/B Standby booster pump’s motor-control-block to 1 (‘Start’ command for the Standby Booster Pump is sent to PMS). Upon receipt of Standby pump running feedback, 33‑LIC‑5100 output sets the output of 331-P-001A/B Duty Booster Pump-A motor-control-block to 0 (‘Stop’ command for the Duty booster pump-A is sent to PMS).
331-P-001A/B shall continue to run till 331-LI-5100 falls below the Low control set point. Stop command for booster pump 331-P-001A/B is sent to PMS over the serial link. 331-P-001A/B shall stop and remain stopped till 331-LI-5100 increases above the High control set point and the cycle will continue.
Motors above 1500 kW
11 kV, 3 Phase, 3 Wire, 50 Hz AC with system neutral earthed through resistance
Motors from 0.20 kW to (including) 233 kW
400V, 3 Phase, 3 Wire, 50 Hz AC with system neutral solidly earthed
Motors less than 0.20 kW
230 V, 1 Phase, 2 Wire, 50 Hz AC
Two nos., Unit Control Panel (UCP) + Generator Control Panel (GCP) – Intelligent Generator Protection Relay, AVR, Exciter Controls etc. and a common Synchronizing Panel.
11 kV Main Switchboard
VSDS Panel (2 Nos.)
400 V Utility MCC
400 V Process MCC
400 V Emergency MCC
Emergency DG Set Control Panel
230 V AC UPS (4 Nos.)
110 V DC UPS (2 Nos.)
a. Local Control for the Incomer breakers under ‘Test’ position.
b. Remote Control from the PMS under ‘Service’ position.
a. Local Control for the Incomer breakers under ‘Test’ and ‘Service Position’.
b. Remote Control from the PMS under ‘Service’ position.
Ensure that incomer breakers and outgoing feeders of the Plant Emergency MCC are all OPEN.
Start manually, the Emergency Diesel Generator set from the Local Power Panel or EDG control panel of the EDG set.
(a) Black Start: The EDG set can be started if the starting batteries are in fully charged condition. The starting batteries of the EDG set are rated for 3-starts with an interval of 10-sec before lockout. Alternatively, the EDG can be started using compressed air system with sufficient storage to provide air for 3-starts with an interval of 10-sec.
(b) Energize the Emergency MCC by closing the DG Incomer Breaker on to the Dead-Bus. The closing of the breaker is automatic if DC-UPS power is available and is carried out manually from the LV switchboard if the DC-UPS supply is not available.
Outgoing feeders to Main Emergency Lighting Distribution Board connected to emergency switchboard
Outgoing feeder to Auxiliary Distribution Board of EDG
Outgoing feeder to substation HVAC panel
Outgoing feeder to control room HVAC panel
Outgoing feeder to substation AC UPS
Outgoing feeder to substation DC UPS
Outgoing feeder to Emergency Auxiliary Distribution Board
All outgoing feeders from 230 V AC UPS Distribution boards
All outgoing feeders from 110 V DC UPS Distribution boards
Outgoing feeder to Switchboard for GTG-A or B
Outgoing feeder to other critical loads, if any
Outgoing feeder to Instrument Air Compressor-A/B/C (only one allowed to start)
Outgoing feeder to HP & LP Methanol Injection Pump Electric Motor
Outgoing feeder to nitrogen Generation Electric Heater Thyristor Control Panel
Outgoing feeder to Flare KO Drum Pump Electric Motors
Outgoing feeder to Flare KO Drum Thyristor controlled Electric Heater.
Outgoing feeder to other critical process loads (if any) connected to the Emergency Switchboard
Starter Motor
Lubricating Oil Pump Motor
Oil Mist Eliminator Fan
Liquid Fuel Oil Pump
Main Enclosure Vent. Fan 1 & 2
Vent Air Filter Fan Bleed Fan
Wash Water Skid Motor
ABLOC Fan 1, 2 & 3
CACA Fan 1 & 2
Lube Oil Tank Heater No-1, 2 & 3
GT Gas Fuel Trace Heating
Fire Protection System
Engine Cleaning Unit
Combustion Air Filter
Ventilation Air Intake Fan Motor Control
Close breakers 52-U1 & 52-U2, 52-P1 & 52-P2 (323-MMS-1-1) and energize the Utility and Process MCC Switchboard with the respective Bus-coupler breakers kept open.
Close tie breaker -52E1 in the Utility MCC to supply LV power from the Utility MCC Switchboard to the Emergency Switchboard.
Operator to initiate the Auto-synchronizing of the Tie Breaker-52E2 (These tag Nos. are with respect to operating philosophy SLD) (Refer Doc. 300‑EEL-DBP-001) (Emergency Switchboard) either from the PMS or from the EDG GCP (EGCP) panel. The synchronizing of the EDG is done by the synchronizing panel within EGCP. On achieving synchronism (of EDG with normal supply) the command to close the Tie Breaker-52E2 is issued by the EDG GCP panel automatically.
On closure of Breaker-52E2 in the Emergency Switchboard, the normal and EDG supplies are running in parallel and feeding the Emergency Switchboard load.
This is followed by un-loading of the EDG and tripping the EDG incomer Breaker-52E2 from the EDG- GCP panel.
Under plant normal operating condition, one or two GTGs are running and feeding power to the 11 kV HV Switchboard. Load sharing between GTGs is to be achieved through PMS.
All the bus-coupler breakers of the HV Switchboard are closed and the HV Switchboard will operate as a continuous bus.
All the outgoing power transformer breakers of the HV Switchboards are in circuit feeding loads, LV power to Utility and Process & Emergency switchboards.
The outgoing LV Utility, Process and Emergency power and motor feeders are in circuit based on the process operating conditions.
The Emergency DG is under standby condition.
The 230 V AC UPSs are energized and continuously feeding the instrument, telecom and the PMS loads of the plant.
The 110 V DC UPS is energized and will feed the breaker control supply of the HV, & LV Switchboard.
The 24V DC System of the each of the GTGs are energized and feeding the critical loads of the GTGs.
GTG MCCs have two incomers, one connected to Utility MCC and the other to Emergency MCC. When power is fed to plant from GTG, the incomer connected to Utility MCC will be kept on and the other will switched off.
Under plant normal operating condition, when the GTG supplying the entire load of the plant trips on fault, the entire plant will be shut down.
Only the AC and DC UPS supply is available catering to the plant critical instruments, telecom and control supply for HV/LV breaker operations.
On loss of normal supply and on sensing of sustained under-voltage condition at the mains incomer of Emergency MCC, the under-voltage relay at Mains Incomer of Emergency MCC will initiate an emergency ‘Start’ command to GCP of EDG.
The EDG is expected to develop the rated voltage in 20 seconds. The breaker-closing operation to ensure power to the emergency switchboard is carried out by the PMS automatically without intervention of the operator, based on initiation from the EGCP. The PMS will also carry out the tripping of the tie feeder from Utility MCC manually to prevent back-feed of power from the Emergency DG to Utility Switchboard. With this, critical emergency loads at Emergency boards is catered by the EDG set via the power feeders that will remain closed even on loss of Main GTG power. Motor feeders shall however be started manually since on loss of power, these feeders would have tripped on account of supply under-voltage.
Once the operator has established and cleared the fault that caused the GTG tripping, the running GTGs is brought back into circuit. In the event of a major fault on the tripped generator, then the operator has to establish the process power requirement by bringing in the Standby Generator into circuit.
On tripping of one of the operating GTGs, the PMS will sense a sustained under- voltage/under-frequency condition, if the operating load on the system at the instant of GTG tripping is greater than the capacity of the one operating generator.
To prevent the remaining operating Generator from tripping on under-voltage or under-frequency condition, on loss of power from the tripped GTG, load shedding shall be resorted to in real time through hard-wired commands (for HV loads) or serial link (for LV loads) and shall be performed by PMS. PMS shall be pre-programmed with load-shedding priority tables.
The philosophy for load shedding in GGS will be developed in coordination with process operation group depending on the priority of loads.
Under plant normal operating condition with one or two GTGs feeding the plant loads, when one of the large motors, say, the Field Gas compressor motor trips, a sudden load throw-off condition is sensed by the 11 kV System.
The GTG control panel will sense an over-voltage or over-frequency condition. The Control Systems of the GTGs – Siemens Simatic-400 PLC which are all operating in parallel, will sense an over-voltage or over-frequency condition on the 11 kV System due to the sudden rejection of a large load. Accordingly the PLCs will reduce the output speed and voltage of the operating GTGs. The quantum of load rejection or load acceptance which each GTG has to share shall be in proportion to the inertias of the GTGs.
On loss of one of the large motors, the ICSS shall take up control of the process by closing of the necessary loads based on the Plant Process Operating philosophy.
Operator shall study the Electrical Fault Sequence of Events (SOE) recorded at the PMS/ICSS causing the tripping of the large motor on fault. Based on the type of fault, the operator shall decide if the fault is major or minor.
If minor, the fault shall be cleared by the operator in minimum time keeping the generator/s in operation on reduced load. On clearance of the fault, the large motor shall be brought back into circuit by the operator via ICSS at the specified loading conditions.
If the fault is major requiring a major process shutdown, then one of the two GTGs may be tripped, causing the plant to operate only on one GTG feeding the plant minimum load.
During sustained overload on the system, as monitored by the PMS/DCS, the Operator/PMS can initiate the starting of the second GTG or EDG if time permits. Else the operator/PMS shall initiate the tripping of non-critical loads to maintain the load within the generation capability of one GTG. The tripped loads can be brought back into circuit by the operator after starting of the 2nd GTG. In case any 11 kV or 400 V large loads are being started by ICSS, it should check whether the load shall overload the generator/s or not through the PMS. The PMS will keep the ICSS updated by sending the total available power at any instant as an analog signal through the serial link.
On loss of supply to bus-section A or B of the Utility or Process MCC, under-voltage condition is sensed at the switchboard which will then self-initiate a slow bus transfer, enabling the closing of the bus-coupler breaker within a short duration, thus resuming power to the entire switchboards.
In case of failure of Auto-transfer, the affected bus section load will lose power. In the event of power loss to the bus section feeding the emergency switchboard and in the event of Auto transfer fail, the emergency switchboard associated with that section will also lose power. The EDG is started only on sustained under-voltage on Utility switchboard which implies a loss of main GTG power.
If the EDG is required to be operated to meet the emergency switchboard loads which has lost normal source of power, then the operator shall take a conscious decision and carry out manual closing of the EDG incomer breaker and tie feeder breaker from the EDG control panel after ensuring the normal power tie feeder is tripped due to loss of power and not on account of fault. The starting of the EDG to meet this scenario is purely at operator discretion. Once the normal power is established, the reverse paralleling sequence to establish normal power to the emergency board will also be carried out by the Operator manually from the EDG CP.
Generator Synchronization/Breaker Control
Generator Excitation
Generator Protection Monitoring
Automatic Voltage Regulation (AVR)
Metering
Interlocks with Unit Control Panel (UCP) will have its own Simatic-400 PLC (for turbine sequencing, control, governing and protection) and ICSS, both of which are located in the Control Room
GCP will also perform the following functions: Excitation control (for Automatic voltage regulation/power factor control/reactive power control). The system provided has the ability to automatically synchronise the unit to the bus through operator action initiated from the GCP panel. The control system will also provide protection against high temperature of generator stator windings.
Composite Generator protection with Numerical relay Siemens make 7UM6211 (part of GCP) having following protection functions: 27-undervoltage protection, 32-Reverse Power protection, 40-generator field failure protection, 51V-Voltage controlled time dependant over-current protection, 51-IDMT over-current relay, 59-overvoltage protection, 87-differential protection, 58-diode supervision, 81‑under-/over-frequency protection, 46-Negative phase sequence protection.
Meters – ammeter, frequency meter, kW/kVAR meter, voltmeter, power factor meter, synchroscope, exciter field ammeter, exciter field voltmeter.
Selector/Control switches including – Local/Remote selector switch, Auto/Manual selector switch, Voltage/speed – Raise/Lower pushbuttons, Generator output breaker control switch, manual synchronizing lights, and manual synchronizing interlock switch.
AC & DC UPS
GTG auxiliary power supply switchboards
Emergency generator auxiliary power supply switchboard
Diesel Transfer Pump
Flare Knockout drum pumps and Electric Heater
HP and LP Methanol Pumps
Start-up Fuel Gas Heaters
Ignition Transformer for flare package
nitrogen Generation Electric Heater
Instrument Air Compressor Package
Field Gas Compressor auxiliaries which require safe shutdown or quick start-up
Main Emergency Lighting Distribution board
HVAC Loads (Substation, Control Room)
The 400V Utility MCC (323-MCC-1-1) is fed by two incoming lines, feeders from two nos. 11/0.420 kV, 2500 kVA distribution transformers (i.e., 323‑TML‑1‑1A and 323-TML-1-1B). The switchboard consists of two incomers and a bus-coupler and various outgoing motor feeders and bulk power feeders. The rating of the switchboard is 4000 A, 400 V, 3 Phase + Neutral, 4 Wire, 50 Hz, 80 kA for 1 sec.
The 400 V Process MCC (323-MCC-1-3) is fed by two incoming feeder from two nos. 11/0.420 kV, 1600 kVA distribution transformers (i.e. 323-TML-1-3A and 323‑TML-1-3B). The switchboard consists of two incomers and a bus coupler and various outgoing motor feeders, heater feeders and bulk power feeders. The rating of the switchboard is 2500 A, 400 V, 3 Phase + Neutral, 4 Wire, 50 Hz, 50 kA for 1 sec.
The 400 V Emergency MCC (323-MCC-1-2) is fed by two incoming feeders, one from the 400 V Utility MCC (323-MCC-1-1) and second from 1200 kW Emergency DG Set. The rating of the switchboard is 3000 A, 400 V, 3 Phase + Neutral, 4 Wire, 50 Hz, 80 kA for 1 sec.
Closing/opening of all LV incoming, bus coupler, outgoing ACB feeders.
Closing/opening of all LV motor breakers, heater feeders without Thyristor Control Panels based on the command from ICSS.
Measurement of all important electrical system parameters including:
1. Monitoring of the fault status from the output of intelligent relays provided in the LV switchboard.
2. Recording and reporting of Sequence of Events (SOE) of feeders including motor feeders and Incomer Feeders following a trip.
3. Transmitting of all outgoing motor feeder contactor and fault status (as required) to the ICSS
(a) Individual Instrument load supplies – 400V, 3 Phase UPS
(b) Telecommunication load supplies – 230V, 1 Phase UPS
DCS
ESD
F&G
RTU (Remote Terminal Unit), Remote I/O and SCADA for Well heads
ESD Matrix
Fire & Gas Matrix
Operator Work Stations
Engineering/Maintenance Work Stations
Historian
Plant Management System and
Management Information System
ENG/SENG station (Dual screen)
PRM (FDM) Station
SIOS station
Master file server
Color laser A3 printer – 5 Nos.
Laser printer.
Processor
Power supply
Communication with ESD and F &G subsystems
Communication with UCP for major package units
Field gas compressors
Main power generators
Instrument air compressor
Instrument air dryer
HVAC systems
Nitrogen generation units
Main Power Generators GTG
Stabiliser Compressors
Expander
Sales gas compressors
De Ethanizer compressors
Instrument air compressors
Instrument air dryer
HVAC systems
nitrogen generation units
ESD Level 1 – Total facility shutdown with Auto depressurization.
ESD Level 2 – Total Process shutdown with depressurization enabled, but operator has to initiate depressurization.
ESD Level 3 – Unit Process shutdown/individual equipment shutdown with depressurization as necessary.
Test gauge is screwed into test point.
The trip over-ride valve is un-locked.
The trip over-ride valve is depressed & held in the over-ride position.
The field trip pushbutton is depressed and input signal sent to the ESD to trip the valve.
The ESD de-energizes its output and switches the respective solenoid to vent.
The ICSS system shall annunciate valve in local test on the HMI screen/alarm banner.
The ICSS shall inhibit valve limit switch feedback discrepancy logic since the actuated valve will not trip.
The operator conducting the test shall verify that the solenoid vents the air pressure.
The field reset pushbutton is depressed and input signal sent to the ESD to reset the valve.
Valve in Local test shall be removed from the HMI screen.
The ESD re-energizes its output and switches the respective solenoid to supply air.
The operator verifies that the air pressure is restored.
The trip over-ride valve is released and key removed (if not already done).
The test gauge is removed and the test point is resealed.
F&G status indication (Green LED ON when F&G system is healthy in a zone)
MAC actuated indication (Red LED ON when MAC actuated in a zone)
Fire detection indication (Amber LED ON when a fire detector senses fire)
Combustible gas detection indication (Blue LED ON when a gas detector senses combustible gas leak)
Toxic Gas detection indication (Yellow LED ON when a gas detector senses combustible gas leak)
Inhibit enabled indication (White LED ON when an input inhibited in a fire zone)
Flammable Gas detectors
Toxic Gas Detector (Only in GTP)
Flame detectors
Smoke detectors
Heat detectors
HSSD
Beacons/Lamps
Sounders
Flammable Gas Detectors (DFR) are Infra Red (IR) type
Flame Detectors (DFR) are Infra Red radiation type or UV type. In some places fusible plugs are also used as flame detectors
Heat detectors (ROR) are used inside buildings in non-hazardous area only and they are ‘rate of rise’ semiconductor type
Toxic Gas Detectors (DGT) are semiconductor type and are installed only in GTP
One type of hydrocarbon detectors is Open Path type hydrocarbon gas detectors (DGOR/DGOT). This has a transmitter and receiver type arrangement to detect gas leak
Hydrocarbon is also detected by IR type point detectors (DGP)
Hydrogen detectors (DGH) are used to detect hydrogen gas alone
Smoke detectors are optical type and used in non-hazardous area only
HSSD is the High Sensitive Smoke Detection system used in buildings to detect the fire at an early stage
Beacons (DAL) are the lamps for alerting the personnel in case of fire or gas leak. Red lamp is to indicate Fire. Yellow lamp is to indicate Gas leak
Manual fire Alarm call points (DMC) to initiate Fire Alert Sounders (DAS) are dual tone type. It sounds in different tones, during fire and gas leak. These dual tone sounders are mainly used in plant area only. Fire alarm bells are used for the buildings
The Following fixed pre-set tones are programmed in to the Sounders:
A Zone alarm & a common Confirmed Fire alarm are indicated at the matrix panel and ICSS
Also a common alarm is generated in ICSS and displayed in graphic display; the event is recorded
A Local Visual & Audible alarm is initiated
A Confirmed Fire signal is sent to ESD1
A fire alarm is indicated at the matrix panel and ICSS
Also a common alarm is generated in ICSS and displayed in graphic display; the event is recorded
Confirmed fire alarm at the Matrix panel/ICSS
A common alarm is displayed at ICSS and a visual alarm is initiated locally
A Confirmed Fire signal is sent to ESD1
A flammable gas Low alarm/Confirmed Flammable Gas High alarm is indicated at the matrix panel and ICSS
A common alarm is generated in ICSS and displayed in graphic display; the event is recorded
Confirmed Flammable Gas High alarm at the Matrix panel/ICSS
A common alarm is displayed at ICSS and a visual alarm is initiated locally
A confirmed 20% LEL/3LFLM Gas signal is sent to ESD1
If the detector is at fault, the event is printed and displayed in the graphic display; also, a detector fault common alarm is sounded in ICSS
A Flammable Gas Low alarm is indicated at the matrix panel and ICSS in the case of 10% LEL
A Confirmed Flammable Gas High alarm is indicated at the matrix panel and ICSS in the case of 20% LEL
Also a common alarm is generated in ICSS and displayed in graphic display; the event is recorded
Confirmed Flammable Gas High alarm at the Matrix panel/ICSS
A common alarm is displayed at ICSS and a visual alarm is initiated locally
A confirmed 20% LEL/3LFLM Gas signal is sent to ESD1
Simultaneous actuation of a minimum of two flame detectors
Simultaneous actuation of a minimum of two smoke detectors
Simultaneous actuation of a minimum of two heat detectors
Actuation of one fusible bulb or frangible bulb
Actuation of one Manual Call Point
Emergency lighting within building and plant
Emergency communication equipment such as radio and telephone
Fire & Gas system
Ignition panel of Flare package
ICSS in the control room
Control room and Substation building HVAC systems
Smoke alarms
Alarm delays
Relay output for remote indication and system faults
Fault levels for airflow, detector monitoring and power failure etc.
Viewing the status of any device in the system
Recording an event log for later use
Aspirator pump speed control
Maintenance interval programming
Air flow supervision with High and Low flow fault setting
Sensitivity adjustment of individual detectors
Field programmable alarm with corresponding output relays
Adjustable time delay for alarm threshold
Lights and audible test
Reset capability
Fire zone isolation
Test, isolate and reset from panel switches
Over-rides of outputs
Control room building
Substation building
Warehouse & workshop building
Accommodation & Gatehouse buildings
Fibre Optic Cable (FOC) for intra- and inter-plant connectivity
Fibre Optic Transmission System (SDH) to provide voice, video, data and telemetry signalling transmission among various sites
Telephone System for General Voice Communication among various sites
UHF Trunk Radio System for Plant/Field Area Mobile Communication
Radio Tower for mounting radio antennas
Environment Monitoring System for monitoring critical weather parameters
Data Network – LAN/WAN
Entertainment System for distribution of audio/video programs
Telecom Supervisory System for supervision of all telecom subsystems at a centralized location
Power Supply System for reliable power supply to all the telecom subsystems
SDH transmission/multiplexing equipment
Ethernet switches
Media converters (for well head communication)
Equipment enclosures
Miscellaneous wire, cable, connectors and mounting hardware
Ethernet channels for Data Networks and WAN/LAN
1 x 2 Mbps channel for Trunk Radio System between GGS & GTP
Subscriber voice channels extended from the GTP PABX
Other services like Alarms, Engineering Order Wire and Supervisory Services
Temperature, barometric pressure, wind speed, wind direction, rainfall and relative humidity sensor
A heavy duty, tower/pole, hinged at ground level for instrument access with full height grounding kit
One PC based work stations along with a printer and weather monitoring system software at TER
One PC-based work station, with user level rights, at GTP CCR
One PC-based work station, with user level rights, at GGS Control Room
Sensor interface module
Field Gas Compressor (304-K-001A/B)
Condensate Pumps (302-P-001A/B)
Early Operation Condensate Pumps (302-P-002A/B)
TEG Make-up Pump (305-P-002)
Glycol Circulation Pump (305-P-003A/B)
EDG
GTGs
: 8.6 barg
: 8.4 barg
: 8.0 barg
: 7.7 barg
: 4.5 barg
Gas Flow Lines Manifold
Production Separator
Sample collection SC-301
Condensate Coalescer 302-F-002A
Sample Collection SC-314
Condensate Coalescer 302-F-002B
Condensate Solid Filters (302-F-001A/B)
Early Operation Condensate Pumps (302-P-002A/B)
Produced Water Storage Tanks 334-T-001
Fuel Gas KO Drum (321-V-001)
Field Gas Compressor Aftercooler (304-E-001A/B)
Flare KO Drum Pump (331-P002A/B)
TEG Regeneration System (305-X-001)
Gas Dehydration Column (305-C-001)
Field Gas Compressor Suction KO Drum (304-V-001A/B)
Field Gas Compressor Package (304-X-001A/B)
Trunk Line: Start-up of GGS after planned shutdown
Production Separator: For start-up after complete shutdown/commissioning
Gas Export Header: After start-up and stabilization of GGS for normal operation of plant
Start Stage 1: The enclosure is purged and any other processes that don’t require the enclosure to be fully purged are carried out (e.g. testing of the emergency lubricating oil pump)
Start Stage 2: Processes that require a fully purged enclosure are carried out. (e.g. testing of fuel valves)
Acceleration to Spin Speed: The starter motor is engaged and the turbine is accelerated to spin speed
Spin Period: The engine is held at its nominal spin speed to allow for the exhaust and associated duct work to be purged of any gas fuel vapour from previous operation (Nominally 3000 RPM)
Pre-Ignition: Any processes that are required prior to ignition are carried out (e.g. priming of liquid fuel system)
Ignition: The igniters are energised and fuel is introduced. A failed ignition on gas fuel will cause the start sequence to revert back to the spin period in order to allow ignition to be attempted several times. On liquid fuel the unit will trip in the event of a failed ignition attempt
Acceleration to Dwell Speed: The fuel and starter motor demand is increased to cause the engine to accelerate. During this phase the starter motor will be disengaged once the speed exceeds a required limit
Dwell Period: The engine is held (if required) at dwell speed to allow for warming of the engine (Nominally 8500 RPM)
Acceleration to Minimum Governed/Nominal Speed: The engine is accelerated to its minimum governed PT synchronous speed for a generator set (50Hz speed is 9525 rpm). Achieving this speed marks the end of the start sequence and the start of the running period
Loaded Operation: The engine is available for loading/unloading as required
Stop Holds: The engine is held for any processes that need to be carried out following the initiation of a normal stop sequence. (e.g. change to gas fuel for a short period on gas to purge liquid fuel nozzles)
Ramp to Minimum Governed Speed: The unit is automatically unloaded and lowered to minimum governed PT speed. On a generator set the generator breaker will be automatically opened once the load drops below a set minimum level (500 KW). A generator set will enter the ‘Shutdown’ state at this point.
Starter Motor
Lubricating Oil Pump Motor
Oil Mist Eliminator Fan
Liquid Fuel Oil Pump
Main Enclosure Vent. Fan 1 & 2
Vent Air Filter Fan Bleed Fan
Wash Water Skid Motor
ABLOC Fan 1, 2 & 3
CACA Fan 1 & 2
Lube Oil Tank Heater No-1, 2 & 3
GT Gas Fuel Trace Heating
Fire Protection System
Engine Cleaning Unit
334-PV-5409 to Flare, 302-LV-1114 Production separator level control valve and 334-LV-5444 for degassing drum
Ensure availability of power
Ensure all utilities are available at specified conditions as detailed under Section 11 above
Ensure safety systems are in place
Ensure DCS and ESD systems are taken on line
Line-up one Well head to start with (subsequent Wells are lined up after start-up of Production Separator)
Establish glycol circulation in dehydration column and regeneration section
Start Production Separator
Start Condensate System
Start Field Gas Compressor (LP system)
Start Dehydration System
Start Oily Water System
Set all the Fail-Closed valves to the open position and all Fail-Opened valves to their closed position.
Activate each one of the unit blocks for ESD Level-1, ESD Level-2 & ESD Level‑3 and check for the sequence of tripping. Refer Cause & Effect Diagram No: 250‑EPR-CNE-05001 for all the ESD-1, 2 & 3.
Verify that the ESD valves function as per the ESD logic. The ESD Level-1 will open depressurizing valves; ESD Level-2 will enable depressurization and ESD-3 is used to only isolate or shutdown systems.
Reset the system and verify all valves have returned to normal operating positions.
Similarly activate Fire & Gas Shutdown System and check whether the indicated valves failed as indicated in the C&E diagram.
Force open 302-XV-1102 and line-up condensate to the Early Operation Condensate Pumps (302-P-002A)
Suction valve of 302-P-002A
Discharge valve of 302-P-002A
Pump safety valves 302-PSV-0135A should be car sealed in the open position.
Inspect all glycol and gas lines; ensure they are all tight. Hot glycol can leak through connections which might be considered tight when cold. Hence it is necessary to re‑tighten some connections once the hot glycol is being circulated under pressure.
Inspect all instruments and adjust where necessary.
Check the levels inside the vessels.
Check the pressures of the Gas Dehydration Column 305-C-001 to be atleast upto 7 barg.
Check the pressures of the Flash Drum 305-V-002 to be 3.8 barg.
Check the pressure of the Fuel gas KO drum (305-V-004) to be 5 barg.
Check the availability to operate of all electric motors (Pumps, Blowers and Air Fans)
Hazop Action Action No. 758
Drain the liquid accumulated in the Vent Gas KO Drum (305‑V-003) by observing the Level gauge 305-LG-3135. If it is prolonged shutdown drain KOD and also ensure to switch on the heat tracing on the pipelines to maintain the fluidity in the line. The Field operators should ensure regular observance of the Vent Gas KOD liquid level and drain the liquid at frequent intervals. If the level builds up, then entrainment to Blowers will cause potential damage to the Blowers.
The block valves upstream of ESD valves 304-XV-1200 and 304-XV-1201 for Field Gas Compressor-A is kept in closed condition. Install blind in the D/S flange of second block valve.
The block valves upstream of ESD valves 304-XV-1300 and 304-XV-1301 for Field Gas Compressor-B are kept in closed condition. Install blind in the D/S flange of second block valve.
The flame detector tag 305-BE/BSL-3163 does not signal flame presence.
The limit switch 305-XZSL-3169 does signal that the Shutdown Valve 305‑XV‑3169 in the pilot fuel gas line is closed.
The limit switch 305-XZSL-3168 does signal that the Shutdown Valve 305‑XV‑3168 in the pilot fuel gas line is closed.
The limit switch 305-XZSH-3165 does signal that the Shutdown Valve 305‑XV‑3165 in the pilot fuel gas vent line is open.
The limit switch 305-XZSL-3167 does signal that the Shutdown Valve 305‑XV‑3167 in the main burner fuel gas line is closed.
The limit switch 305-XZSH-3166 does signal that the Shutdown Valve 305‑XV‑3166 in the main burner fuel gas line is closed.
The limit switch 305-XZSH-3170 does signal that the Shutdown Valve 305‑XV‑3170 in the main fuel gas line is open.
The limit switch 305-XZSL-3171 does signal that the Shutdown Valve 305‑XV‑3171 in the stripping gas line is closed.
1. Press ‘Start Burner’ pushbutton and the following operation are done in automatic sequence:
Start the Burner Air Fan 305-K-001A by pressing the Start pushbutton 305‑MHSM-3182.
The Burner Gas Blower 305-K-001A running indication is displayed on DCS panel by 305-MXI-3182.
Start the selected Vent gas Blowers (305-K-002A/B) by the following actions and line-up to the TEG Incinerator.
Start the Vent Gas Blower 305-K-002A by pressing the Start pushbutton 305-MHS-3131B in the local panel.
The Vent Gas Blower 305-K-002A running indication is displayed on DCS panel by 305-MXI-3131.
Similarly start the other Blower 305-K-002B and ensure the two Vent gas Blowers are running in series
Force “Open” Fuel Gas Control Valve 305-TV-3109.
When both the blowers ‘Running’ signal appears for 305-K-001A or B, 305‑K‑002A/B or (C/D) and the valve 305-TV-3109 is open, and air flow is established by 305-FALL-3147 (reset).
Start “Purging” gives signal with ‘Purge On’ (305-XL-3158) indication on local panel 305-PKG-LCP-01 for 60 seconds.
After 60 seconds of purging, force open control valve 305-TV-3109 to minimum position, switch off the indication ‘Purge On’ on local panel beside the burner.
After the control valve 305-TV-3109 is set to minimum (confirmed by limit switch 305-TZSL-3109, open shutdown valves 305-XV-3168 & 305-XV-3169 and close 305‑XV‑3165 on pilot gas line.
Power is given to the Spark Ignitor for 30 seconds 305-EE-3164.
When the limit switches 305-XZSH-3168, 305-XZSH-3169 and 305-XZSL-3165 give signal that the valves have reached the desired position, the spark ignitor 3005‑EE-3164 ignites for 30 seconds.
If the flame scanner detects the flame within 30 seconds ‘Pilot On’ lamp (305‑XL‑3157) glows on the local panel.
If the flame is not detected within 30 seconds, ‘Flame Scanner Fault’ indication glows indicated by 305-UA-3154 and once again the purging procedure starts.
“Pilot On” lamp (305-XL-3157) lights on in local panel.
After the Pilot flame is stabilized, open shutdown valves 305-XV-3167 and 305‑XV-3166 and close 305‑XV‑3170 on the main gas burner line.
When the limit switches 305-XZSH-3167, 305-XZSH-3166 and 305‑XZSL‑3170 give signal that the valves have reached the desired position, start 30 seconds of main flame stabilization.
When the Main flame stabilization time is over and the burner start-up sequence is completed, ‘Burner On’ indication appears on the local panel (305‑XL‑3156B) and on DCS (305-BAH-3156A).
At this point the automatic sequence should remove the force controls on 305‑TIC-3109 but some adjustments on the main burner shall be required. Therefore it shall be convenient to keep the control in manual mode since the main flame is properly adjusted.
Open the valves on the start-up line 2”-305-GY-1015-11A-P and start the glycol circulation starting a pump and allowing the warm up of the Reboiler and surge drum.
When the temperature inside the Surge drum reaches approximately 90°C, open the valves on the start-up line 2”-305-GY-1023-11A-P and close the line 2”‑305‑GY-1015-11A-P allowing to warm-up the Flash drum and the glycol filters.
When the temperature inside the Reboiler reaches 1500C, start the Glycol circulation to the Gas Dehydration Column 305-C-001.
Open the shutdown valve 305-XV-3003, then close the valves on the recirculation line previously opened (Globe valve first then the Ball valve). The pressure on the pump outlet will increase upto the required pressure to allow the glycol enter the column and then open the shutdown valve on the outlet line 305‑XV‑3002
The level inside the Chimney tray shall be controlled by the valve 305‑LV‑3017.
Pressure and temperature profile along the unit
Operating levels in the Gas Dehydration Column process vessels
Pressure drop across glycol filters
Pressure drop inside contactor (across the structured packing)
Operation of glycol pump
Glycol flow rate
Maintain a constant temperature of gas feed at 50°C (LP mode) as indicated by 305-TI-3019. Accordingly maintain the lean Glycol temperature of 55°C i.e., 5°C above the inlet gas temperature to avoid hydrocarbon condensation. The temperature is maintained by dry gas/lean glycol heat exchanger
Collect samples at the outlet of the Gas Dehydration column SC-502 to find out the dew point and the water content of the dehydrated gas.
Water is boiled off glycol at the TEG Reboiler and water & aromatic vapours pass on to the tube side of the reflux exchanger.
Cold rich glycol from the glycol absorber passes through the shell side of the exchanger and partly condenses the water vapours.
The operator will be alerted at 80.6 barg by Low pressure alarm 305-PAL-3009 and should take immediate action to identify the cause and close 305-PV-3024
High flow alarm in the Flare Header by 331-FAH-5126.
The bigger control valve 305-PV-3009A closes fully and the pressure is controlled only by smaller control valve 305-PV-3009B
Open the valves on the Start Up line 2”-305-GY-1015-11A-P and start the glycol circulation starting a pump allowing the warm-up of the Reboiler and Surge Drum.
When the temperature inside the Surge Drum reach approximately 90°C, open the valves on the start-up line 2”-305-GY-1023-11A-P and close the ones on line 2”-305-GY-1015-11A-P allowing to warm up also the Flash Drum and the filters. This will allow all equipment to slowly warm-up and will avoid thermal shock. When the temperature inside the reboiler reaches 150 °C, can start the Glycol circulation on the Gas Dehydration Column 305-C-001.
If the temperature in the reboiler is already above 90°C, warm up can be avoided.
Increase the temperature in the reboiler at a maximum rate of 60°C per hour.
Do not exceed 204°C in the reboiler.
ESD system checks whether there is main burner start check failure BSL-6051 & BSL-6048 and detection of the burner main flames (alarm BAX-6051 and BAX‑6084) before the opening of the gas valves XV-6033A & XV-6033B and closing of the vent valve XV-6033C.
ESD system checks whether there is pilot flame detection, start check failure BSL‑6070 before pilot ignition trial. Also, ESD checks if there is detection of the pilot flame (alarm BAX-6070) before the start of its ignition
ESD system checks whether the air fan is not running before giving the start command of the system.
Minimum TT-6047 temperature value for gas injection is reached after establishment time of 10 min;
Opening TEG Off-Gas valves XV-6041A & XV-6041B and closing XV-6041C to consent off feed.
Opening Produced Water tank Off-Gas valves XV-6045A, XV-6045B and closing XV-6045C to consent off feed.
Open the shut down valve 305-XV-3003 then close the valves on the recirculation line previously opened (globe valve first then the ball valve). The pressure on the pump outlet line will increase up to the required to allow the glycol enter the column then open the shut down valve on the outlet line 305‑XV-3002. The level inside the chimney tray shall be controlled by the valve 305-LV-3017. The glycol circulation is complete and the glycol temperatures should reach the design values.
Put the stripping gas in service by manual opening from DCS the shut down valve 305-XV-3171 on the stripping gas line.
Start circulation of process gas through the glycol contactor soon AFTER the glycol circulation is established to avoid potential foaming problem in the column.
Feed the glycol contactor with the process gas as smooth as possible.
Despite it is not possible to indicate an accurate value on the feeding rate, it is advisable to have few steps of 25% of the maximum flow, each step being reached in 30 seconds or more.
Increase the temperature in the reboiler at a maximum rate of 60°C per hour.
Do not exceed 204°C in the reboiler.
Monitor the operating pressures, liquid levels and production rates of condensate, gas and water (measured by the flow meters in respective lines) of separators.
Ensure that the pressure and level controllers of Production Separator are in Auto mode. The operating pressure of the Production Separator shall be steady under normal operating conditions. In case of frequent variations, check the functioning of the pressure and level controllers.
Ensure that all methanol injection systems are running and the chemicals are injected at the required rate during winter.
The vapour and liquid flows to and from the Production Separator may change depending on the variation in Gas to Oil Ratio (GOR) of the production fluid and the change in operating conditions of the plant like turndown etc.
Ensure that liquid level in the oil compartments is steady.
Regularly check and ensure that the drain valves of Production Separator are closed and the spectacle blinds are in closed position
Periodically cross-check the levels, temperatures and the pressures of the Production Separator between control room and field wherever possible. Any discrepancies should be rectified.
Ensure free flow of produced water. Check heat tracing on regular basis. Prevent maintenance of H.T.Coil shall be done as per schedule.
The pressure is maintained at 86.75 bara during the HP mode and 26.85 bara during the LP mode. The pressure in the Production Separator is controlled by back-pressure of the gas dehydration column. If for any reason, the Production Separator increases beyond 86.75 bara, then the pressure control valve 302‑PCV‑1137 will open to flare to maintain normal pressure. If the pressure still increases and leads to popping of Production Separator PSV, the choke valve opening can be adjusted or isolate one of the well heads to control the pressure immediately. If the Production Separator pressure reduces, this may be due to tripping of any well head and can be normalised by restarting the well head after attending its fault. If the pressure is still low, then adjust the choke valve opening to get normal pressure in the Production Separator.
The interface level is maintained by the Interface Level Controller 302-LIC-1114 which controls the Produced Water flow through 302-LV-1114 to Produced Water Tanks. The interface level is maintained at a normal level of 650 mm. If the interface level increases quickly, this may be due to increased production flow of gas or increased water content of the well head fluids. Sometimes the bypass of the control valve 302-LV-1114 is operated to control the increased level of water level in the Production Separator.
Maintain the lean glycol flow and temperature as per the increase of the gas feed rate in the gas dehydration column. Maintain the lean TEG temperature 5C above the wet gas entering the gas dehydration column. Adjust the final parameters so that the final moisture content of the dry gas is met.
Pressure drop across the Gas dehydration column should have a normal value of 0.2 to 0.3 bar. In any case, if the differential pressure reaches 0.35 bar, then it indicates foaming problem in the dehydration column. Collect both lean and rich glycol samples frequently to determine the purity of glycol and eliminate foaming.
Vaporisation losses in the regenerator still column can be reduced by satisfactory glycol condensation. Monitor the reflux condenser outlet temperature and maintain it at a temperature of 95C. Also, maintain the temperature of lean glycol within 3 to 6°C to the inlet gas temperature. Avoid excessive gas velocities which will lead to foaming by reducing the gas feed appropriately.
During winter months when air temperature might fall to –15°C (minimum ambient temperature), ensure heating the Gas dehydration column bottom, condensate outlet line and the chimney tray of the gas dehydration column – these are heated by electrical tracing.
When there is foaming in the column, start the antifoam and the corrosion inhibitor injection to various points in the TEG regeneration system
Stabilise the TEG regeneration system with temperatures and flows optimised for efficient operation of the gas dehydration system.
Check the two or more samples to confirm the water content of the dry gas and condensate.
Do not operate the glycol reboiler above 204°C as it will lead to premature glycol degradation.
The estimated TEG make-up requirement is 400 kg once a week.
Antifoam requirement is 10 litres per week. Regular TEG chemical analysis will determine the exact requirement.
Corrosion Inhibitor requirement is 10 litres per week. Glycol pH will determine the exact requirement.
ESD Level -1 Shutdown: ESD Level-1 shutdown will open all the depressurizing valves at the same time.
ESD Level-2 Shutdown: ESD Level-2 shutdown will enable depressurization, allowing for operator action if required.
ESD Level-3 Shutdown: ESD Level-3 shutdowns are used only to isolate or shutdown systems. Individual unit/equipment may be depressurized if necessary.
: 8.6 barg
: 8.4 barg
: 8.0 barg
: 7.7 barg
: 4.5 barg
Starter Motor
Lubricating Oil Pump Motor
Oil Mist Eliminator Fan
Liquid Fuel Oil Pump
Main Enclosure Vent Fan 1 & 2
Vent Air Filter Fan Bleed Fan
Wash Water Skid Motor
ABLOC Fan 1, 2 & 3
CACA Fan 1 & 2
Lube Oil Tank Heater No-1, 2 & 3
GT Gas Fuel Trace Heating
Fire Protection System
Engine Cleaning Unit
Production separator
Condensate system
TEG system (Closes plant outlet)
Inlet manifold (Closes plant inlet)
GTP pipeline
Compressor tripped (No export possible in LP mode)
Hazop Action No. 67
Handling and disposal of Contaminated filter Catridges/Coalescer elements should be done in safe manner. As these filters contain hazardous sulphur and nitrogen compounds this should be collected and disposed in designated storage areas. Proper PPEs as given in Section 2.3 and Precautions should be given to all personnel involved in handling the contaminated equipments to waste storage area.
Stop the gas to the Gas dehydration Column (305-C-001).
Stop the burner of the TEG Reboiler.
Stop the Glycol pump 305-P-003A/B, when the temperature in the Reboiler fall under 190°C.
Stop the Vent gas blower 305-K-002A/B.
Isolate gas dehydration column outlets.
Isolate flash drum condensate outlet and glycol outlet.
Close ball valves at glycol pump discharges.
Leave the gas or vapour outlet of process vessels open.
ESD Level-1 shutdown: ESD Level-1 shutdown will open all the depressurizing valves at the same time.
ESD Level-2 shutdown: ESD Level-2 shutdown will enable depressurization, allowing for operator action if required.
ESD Level-3 shutdown: ESD Level-3 shutdowns are used only to isolate or shutdown systems. Individual unit/equipment may be depressurized if necessary.
Manually by an authorised Operator in the control room or gate house (GGS and GTP)
Automatically via the F&G system on 10% LEL confirmed gas detection in the HVAC inlet of the control room and substation of GGS.
Confirmed fire at the GGS will initiate ESD Level-1 at GGS due to extended periods of unattended operation.
Confirmed high level gas detection (20% LEL) at the utilities area of GGS. This represents the highest level ESD at the installations as these will trip the Emergency Generator.
Automatically, by cascade from ESD Level-1 at GGS & GTP.
Manually, by an authorized operator either in the control room or at selected locations in the plant at GGS & GTP.
Automatically on Low Low instrument air pressure at GGS & GTP.
Automatically, on failure of main power generation at GGS & GTP.
Automatically on High High flare drum level at GGS & GTP.
AT GGS Automatically, on fuel gas KO drum Low Low pressure. All other fuel gas ESD level-3 (like High High level and Low Low temperature) will switch the main power generator to diesel operation. This takes 40-60 seconds but is assumed not to be possible on fuel gas Low Low pressure. After successful automatic change over of GTP to diesel operation, the ESD Level-2 shut down can be RESET after over riding Low Low fuel gas KOD pressure.
AT GTP Automatically, on the fuel gas KOD pressure High High pressure, Low Low pressure, High High liquid level, Low Low temperature will cause ESD Level- 2.
Automatically on FG ESD Level-3 at the GTP (cascades to loss of Power).
Automatically at GGS on confirmed Low Low pressure in the gathering system or at GGS and GTP on Low-low pressure in the GGS to GTP pipeline.
Automatically on sales gas compressor discharge metering pipeline Low Low pressure.
Automatically via the F&G system on:
20% LEL confirmed gas detection in the process area at GGS & GTP.
Confirmed fire detection in process areas, GTP only
Confirmed 20% LEL gas in the generator area will trip or inhibit start of the Main or Emergency Generators (for GGS & GTP)
Automatically, by specified abnormal process conditions (refer to the Cause & Effect Diagrams for details)
Manually, via an ESD pushbutton at the unit (local or on control panel)
ESD-3 actions are typically:
Shut down and isolate a single equipment item or train.
Shutdown and isolate a complete process unit.
On Low-Low pressure of nitrogen, trip, isolate and depressurize the Field gas Compressors (GGS) or Sales Gas Compressors (GTP).
Production Separator/Condensate System ESD LEVEL-3 (closes plant inlet)
TEG System ESD Level 3 (Closes Plant outlet)
Inlet manifold PHH (Closes plant inlet)
GTP pipeline PHH (Closes plant outlet)
Compressors tripped (No export possible in LP Mode)
Main generators will transfer to diesel operation to be available for plant restart
Emergency generator will start to be ready for failures on transfer of the main generators
Well heads will be isolated by closing the chokes to avoid excessive flaring at the GGS.
The remainder of the plant will remain live and, where possible, the Field Gas compressors will continue to run on recycle mode via the anti-surge recycle loop.
Stop the gas flow through the Contactor 305-C-001
Stop the Burner. See Burner stop and sequence from the Vendor manual.
Stop the Glycol circulation pump 305-P-003A/B
Close all the shutdown valves; 305-XV-3212, 305-XV-3213, 305-XV-3001, 305‑XV‑3002, 305-XV-3003 and 305-XV-3004
Stop the Vent gas blower 305-K-002A/B
Open the blowdown valve 305-XV-3000 for depressurization to flare
                        

Similer Documents