CHANGE CONTROL SHEET

GLYCOL REGENERATION

TABLE OF CONTENTS

Section-Page

Introduction

Purpose

Scope

References

Definitions

Responsibility

Safety and Environmental CONSIDERATIONS

Process Overview

Major Equipment Summary

System Summary

Glycol Regeneration

TEG REFLUX CONDENSER (HBG-2340)

COLD LEAN/RICH TEG Exchanger (HBG-2335)

TEG Flash DRUM (MBD-2350)

TEG Filter (MAJ-2345)

ACTIVATED Carbon Filter (MAJ-2340)

HOT LEAN / RICH TEG Exchanger (HBG-2330)

TEG Still Column (ZBE-2310)

TEG Reboiler (BBC-2310)

STAHL Column (ZBE-2320)

TEG Surge Drum (ABJ-2315)

TEG CIRCULATION Pumps (PBE-2325A/B)

START UP, OPERATING & SHUTDOWN PROCEDURES - GLYCOL Regeneration

Cold Start-up Procedure Following a Planned Shutdown.

Hot Start-up Procedure Following a Process Trip

Normal Operational Checks:

Planned Shutdown procedure

Emergency Controlled Shutdown Procedure

Alarm, Trip and PSV Settings

Valve List

Acknowledgements

Tables

Table 1 Operating and Design Conditions for HBG-2340

Table 2 HBG-2340 Temperature Monitoring

Table 3 Operating and Design Conditions for HBG-2335

Table 4 HBG-2335 Temperature Monitoring

Table 5 Operating and Design Conditions for MBD-2350

Table 6 MBD-2350 Pressure Monitoring

Table 7 MBD-2350 Level Monitoring

Table 8 MBD-2350 Temperature Monitoring

Table 9 Operating and Design Conditions for MAJ-2345

Table 10 MAJ-2345 Pressure Monitoring

Table 11 Operating and Design Conditions for MAJ-2340

Table 12 MAJ-2340 Pressure Monitoring

Table 13 MAJ-2340 Flow Monitoring

Table 14 Operating and Design Conditions for HBG-2330

Table 15 HBG-2330 Temperature Monitoring

Table 16 Operating and Design Conditions for ZBE-2310

Table 17 Operating and Design Conditions for BBC-2310

Table 18 BBC-2310 Level Monitoring

Table 19 BBC-2310 Temperature Monitoring

Table 20 BBC-2310 Pressure Monitoring

Table 21 Operating and Design Conditions for ZBE-2320

Table 22 Operating and Design Conditions for ABJ-2315

Table 23 ABJ-2315 Level Monitoring

Table 24 Operating and Design Conditions for PBE-2325A/B

Table 25 PBE-2325A/B Pressure Monitoring

Table 26 Cold Start-up Valve Checklist

Table 27 Cold Start-up Overrides

Table 28 Cold Start-up Procedure Following a Planned Shutdown

Table 29 Hot Start-up Valve Checklist

Table 30 Hot Start-up Procedure Following a System Trip

Table 31 Planned Shutdown Procedure

Table 32 Emergency Controlled Shutdown Procedure

Table 33 Alarm, Trip & PSV Settings

Table 34 Valve List

FIGURE

Figure 1 Process Flow Diagram of the Glycol Regeneration System.

Introduction

This document is part of the Operating Manual, which covers the Glycol Regeneration System. The Glycol Regeneration System operations manual together with other manuals and related documents comprise the Facility Management System or FMS. The Glycol Regeneration System is a controlled document maintained by MODEC INTERNATIONAL LLC, the Contract Operator of the Baobab Field. Any question concerning this document or its contents should be addressed to the Contract Operator.

Purpose

This document gives a general description of and the task lists for the operation of the Glycol Regeneration System. Its purpose is to educate those who are unfamiliar with the system in how it works and the way in which the system is to be started, stopped and operated safely. This document can be used as a reference document in formulating maintenance isolation procedures

Scope

Information contained in this document applies only to the Glycol Regeneration System on the Baobab Field Development project. The information contained gives general design information, alarm settings and trip points for the various components as well as the start up, shut down and normal operating procedures for the Glycol Regeneration System.

References

Refer P&IDs 1072-MI20-9020-0115, 1072-MI20-9020-0126 & 1072-MI20-9020-0127, TEG-Contactor Data Sheet (Doc. No. 1072-2200-G21-0028), Activated Carbon Filter Data Sheet (Doc. No. 1072-2200-G21-0016), TEG Filter Data Sheet (Doc. No. 1072-2200-G21-0026), TEG Flash Drum Data Sheet (Doc. No. 1072-2200-G21-0029), TEG Reboiler Data Sheet (Doc. No. 1072-2200-G21-0030), TEG Reflux Condenser Data Sheet (Doc. No. 1072-2200-G21-0018), TEG Stahl Column Data Sheet (Doc. No. 1072-2200-G21-0031), TEG Still Column Data Sheet (Doc. No. 1072-2200-G21-0032), TEG Surge Drum (Doc. No. 1072-2200-G21-0033), Hot Glycol-Glycol Exchanger Data Sheet (1072-MI20-90DS-2200/23), Cold Glycol-Glycol Exchanger Data Sheet (1072-MI20-90DS-2200/24) and Vendor P&IDs 935-P-DW-201-3/4/5

Definitions

See the Definitions Document of the FMS.

Responsibility

Every plant system covered by the Glycol Regeneration System has been assigned to a single position title in the permanent offshore crew. The person filling the named position is jointly responsible with his off-duty relief for the integrity and the safe operation of the assigned system. In like manner it is that person's responsibility to verify the accuracy of the information contained in this document. Any confirmed inaccuracy shall be tracked by the Offshore Installation Manager (OIM) until formally corrected.

The job title of the position responsible for this system can be found in the System Responsibility Matrix in the Safety Management System (SMS) Manual (1072-MI20-15ST-0170).

Safety and Environmental CONSIDERATIONS

In the execution of the subsequent procedures all permit to work, PPE and isolation procedures required by the Baobab SMS (1072-MI20-15ST-0170) shall be followed. If any doubt exists as to the correctness of valve positions or sequence of operations then they should be discussed with the supervisor and approval sought from the Facility Manager to change the procedure. These changes shall then be captured on a permanent basis by submitting them through the required document control procedures. Specific requirements for HSE are given in each section of the procedures.

Shut down overrides for this system can be invoked only when the system is continuously monitored. Proper procedures and systems should be followed while testing the trips. Where overrides are put in place for testing, these shall be removed at the end of testing so as not to inhibit shutdown functions.

Process Overview

Major Equipment Summary

The main items of equipment within the Glycol Regeneration facilities are as follows:

TEG Flash Drum MBD-2350

TEG Filter MAJ-2345

Activated Carbon Filter MAJ-2340

Hot Lean/Rich TEG Exchanger HBG-2330

Cold Lean/Rich TEG Exchanger HBG-2335

TEG Reboiler BBC-2310

Reboiler Heater HZZ-2310A/B

TEG Still Column ZBE-2310

Stahl Column ZBE-2320

TEG Surge Drum ABJ-2315

TEG Reflux Condenser HBG-2340

TEG Circulation Pump PBE-2325A/B

System Summary

After exiting from Glycol Contractor (MAF-2215), the rich TEG is preheated in the heating coil in TEG Reflux Condenser (HBG-2340) located on top of the TEG Still Column (ZBE-2310) and in the Cold Lean/Rich TEG Exchanger (HBG-2335), before entering the TEG Flash Drum (MBD-2350), where the light hydrocarbons are removed and sent to flare. The rich TEG stream is then sent through two filters, a particulate filter MAJ-2345 (Cartridge Type) and an activated carbon filter (MAJ-2340) to remove particulate and dissolved impurities.

The rich TEG then passes through another hairpin type Hot Lean/Rich TEG exchanger (HBG-2330) prior to entering the TEG Still Column (ZBE-2310) , running down the column where a distributor plate breaks the liquid up to remove any vapor. The rich TEG enters the TEG Reboiler where the Reboiler Heaters (HZZ-2310A/B) heat the liquid to approximately 204 C removing the water. The vapor mainly waters and gas, is directed to the vent to safe location once have passed through the TEG Still Column and the TEG Reflux Condenser.

The lean TEG is sent to a Stahl Column (ZBE-2320) to ensure that liquids only are sent to the TEG Surge Drum (ABJ-2315), via the Hot/Cold Lean Rich TEG exchangers. The lean TEG stored in TEG Surge Drum is pumped back through TEG Circulation Pump (PBE-2325A/B) to the Glycol Contactor (MAF-2215), via gas/glycol heat exchanger (HBG-2220), for reuse by the gas dehydration process. Refer to P&IDs 1072-MI20-9020-0115,1072-MI20-9020-0126 and 1072-MI20-9020-0127 . Figure 1. is a process flow diagram of this system.

Figure Process Flow Diagram of the Glycol Regeneration System.

Glycol Regeneration

The Glycol regeneration system is a closed loop system that removes the absorbed water in the water rich (wet) glycol and regenerates it by:

Flashing hydrocarbon liquids in the TEG flash drum to remove dissolved gas and any light condensate components.

Filtering the Glycol to remove solids and any glycol degradation products.

Removing absorbed water as vapor in the still.

The regenerated lean Glycol is cooled in hot & cold Lean/Rich TEG Exchanger and circulated for reuse by the gas dehydration process. The detailed explanation of each piece of equipment can be seen below.

TEG REFLUX CONDENSER (HBG-2340)

The rich TEG from the bottom of the Glycol Contactor enters a helical coil type heat exchanger at the top section of the TEG still Column termed as TEG Reflux Condenser. In this condenser TEG is preheated in the coil before entering in the Cold Lean/Rich TEG Exchanger. In this condenser the rich TEG reduces the temperature of the glycol/water vapor above the TEG still. This condenser reduces the amount of glycol lost as vapor from the TEG Still Column.

Equipment Description and Control

The condenser is a Stainless Steel helical type heat exchanger having the following operating and design conditions.

Table Operating and Design Conditions for HBG-2340

Temperature Monitoring, Control and ESD Instruments:

The heat exchanger is provided with the following local temperature indicator located on the outlet of the shell and tube. These will be used to determine if fouling is occurring inside the heat exchanger and the heat transfer efficiency:

NOTE - 10M-TI-2340-1 (condenser overhead temperature) is very important for the efficient operation of the unit. The temperature should be maintained at 90 -95°C ,- too high and the glycol losses increase, too low and the water vapor condenses back down the column.

Table HBG-2340 Temperature Monitoring

4.2 COLD LEAN/RICH TEG Exchanger (HBG-2335)

The rich TEG after preheating from the reflux condenser enters the Cold Lean/Rich TEG Exchanger for further preheating; the hot medium is TEG from the Reboiler (BBC-2310) via heat exchanger HBG-2330. The exchanger is lagged for Heat conservation purposes as well as personnel protection.

4.2.1 Equipment Description and Control

Cold Lean/Rich TEG Exchanger (HBG-2335) is a hairpin type heat exchanger constructed from carbon steel.

Table Operating and Design Conditions for HBG-2335

Temperature Monitoring, Control and ESD Instruments:

The heat exchanger is provided with the following local temperature indicators located on the inlet and outlet of the shell and tube. These will be used to determine if fouling is occurring inside the heat exchanger and the heat transfer efficiency:

Table HBG-2335 Temperature Monitoring

Activation of 10M-TI-2335-3 TAHH will cause the glycol re-boiler heater to trip.

4.3 TEG Flash DRUM (MBD-2350)

The function of the TEG Flash Drum is to remove dissolved gases, hydrocarbons and volatile organic compounds (VOC) from the warm rich TEG. The flash tank is operated at a higher temperature and lower pressure than the TEG contactor, so most hydrocarbons flash off as the glycol flows through the drum.

Flashed vapors from the flash drum are routed to the Low Pressure Flare Header. Hydrocarbon condensate collected is routed to the closed drain using the drain line located on the vessel. The liquid TEG from the drum pass to the reboiler under level control by LV-2350-1 through TEG Filter (MAJ-2345), Activated Carbon Filter (MAJ-2340) and Hot Lean/Rich TEG Exchanger (HBG-2330).

4.3.1 Equipment Description and Control

The TEG Flash Drum is a Carbon Steel vertical vessel with an inner diameter of 1067 mm and height (T/T) 3150 mm. The vessel is provided with inlet diverter, HC Skim bucket & Vortex Breaker.

Table Operating and Design Conditions for MBD-2350

Pressure Monitoring, Control and ESD Instruments:

The flash drum is provided with the following pressure indicator, control, alarm and trip instrumentation:

Table MBD-2350 Pressure Monitoring

10M-PCV-2350-6 is a self-regulating pressure control valve set at 3.3 barg, located on the gas outlet line to LP flare. This valve will only pass gas if this pressure is exceeded ensuring there is always a blanket gas on the vessel and a positive pressure. 10M-PCV-2350-9 set at 3.0 barg will maintain a pressure in the TEG Flash Drum to ensure that the TEG is always circulating, as the system relies on differential pressure from the Flash drum vessel to force the TEG through the filters back to the reboiler for regeneration. The process variable from 10M-PIT-2350-7 is used in the process shutdown logic system for activation of both high high and low low-pressure alarms. Activation of the trip settings will result closure of the SDV-2215-1 on the glycol outlet of the contactor as well as closure of the SDV-2310-15, stripping gas to the re-boiler. Refer to section 6.0 for the alarm trip settings.

Level Monitoring, Control and ESD Instruments:

The vessel is provided with the following glycol level sight glass and control instrumentation, level alarm and level trip instrumentation:

Table MBD-2350 Level Monitoring

10M-LT-2350-1 is a level transmitter which modulates control valve 10M-LV-2350-1, via controller 10M-LIC-2350-1, to direct the glycol flow out of the vessel through the filters and on to the reboiler. High and low level alarms are installed to alert the operator to these conditions. The level valve is located on the inlet to the reboiler, ensuring that the heat exchanger HBG-2330 is always filled with liquid.

The process variable from 10M-LT-2350-2 is used in the process shutdown logic system for activation of both high high and low low-level alarms. Activation of the trip settings will close the SDV-2215-1 on the Glycol outlet line of the TEG Contactor as well close SDV-2310-15, stripping gas to the re-boiler. Refer to section 6.0 for the alarm trip settings.

Temperature Monitoring, Control and ESD Instruments:

The flash drum is provided with the following local temperature indicator used to determine the temperature of the fluids at the top of the vessel:

Table MBD-2350 Temperature Monitoring

Over-Pressure Protection:

Over-pressure protection of the vessel is provided by pressure safety valve 10M-PSV-2350-3 set at 10 barg, relieving to the HP flare header One PSV is required to meet the relief capacity of the system.

TEG Filter (MAJ-2345)

The function of the TEG filter is to remove suspended solids from the TEG stream prior to entering the Activated Carbon Filter, Reboiler and downstream components such as the circulation pumps. The suspended solids content of glycol should be kept to a minimum, to minimize pump wear, plugging of exchangers, fouling of absorber trays, solids decomposition in the reboiler, and glycol foaming.

Equipment Description and Control

The TEG filter is a vertical cartridge type filter of Carbon Steel has the following operating and design features. The internal diameter of the filter is 219 mm and height (S/F) 1226 mm.

Table Operating and Design Conditions for MAJ-2345

Pressure Monitoring

The TEG filter is fitted with a differential pressure indicator to alert the operators when there is a high-pressure drop due to a blockage of the filter element. In the event of a high differential pressure the filters may have to be changed or removed and cleaned. A by-pass line is fitted around both the TEG filter and the Activated Carbon filter to allow servicing of the filters whilst the TEG continues to circulate. The filters are also provided with local pressure indicators PI-2345-3 and PI-2340-3, for monitoring the operating pressure of the filters.

Table MAJ-2345 Pressure Monitoring

Over-Pressure Protection:

10M-PSV-2345-2 is set at 10 barg, and positioned on the inlet piping to the TEG filter relieving to the TEG Surge Drum. This PSV provides pressure protection for TEG filter. Should any obstruction occur, this PSV will relieve directly to the TEG Surge Drum therefore by-passing the filters, the heat exchanger and TEG Reboiler.

ACTIVATED Carbon Filter (MAJ-2340)

Activated carbon filter is used to remove dissolved impurities in the glycol, such as high-boiling hydrocarbons, surfactants, well-treating chemicals, compressor lubricants, and TEG degradation products. This filter is located downstream the TEG filter to ensure it is not plugged with particles. A by-pass line is fitted around both the TEG filter and the Activated Carbon filter to allow servicing of the filters whilst the TEG continues to circulate.

Equipment Description and Control

The activated carbon filter is a vertical cannister type filter of Carbon Steel has the following operating and design features. The internal diameter of the filter is 610 mm and length (S/F) is 1420 mm.

Table Operating and Design Conditions for MAJ-2340

Pressure Monitoring

The activated carbon filter is fitted with the following differential pressure indicator to alert the operators when there is a blockage due to a high-pressure drop. In the event of a high differential pressure (more than 0.75 barg) the filter may have to be changed or removed and cleaned. The filter is also provided a local pressure indicator PI-2340-3 on the filter for monitoring the filter operating pressure.

Table MAJ-2340 Pressure Monitoring

Flow Monitoring

The activated carbon filter is designed as a side stream filter to take approximately 25% of full circulation flow. At the inlet of the activated carbon filter flow element FE-2340-3 provided for monitoring the inlet flow of rich TEG to the activated carbon filter.

Table MAJ-2340 Flow Monitoring

Over-Pressure Protection:

10M-PSV-2340-2 set at 10 barg is positioned on the outlet line of the activated carbon filter relieving to the TEG surge drum. This PSV provides pressure protection for Activated Carbon filter vessel.

HOT LEAN / RICH TEG Exchanger (HBG-2330)

The TEG from the activated carbon filter is fed to another hairpin type heat exchanger for further heating before entering the still and reboiler. The warm rich TEG is cross exchanged with the hot lean TEG from the reboiler to pre- heat it prior to entering the Reboiler to reduce the heat load on the Reboiler heater. The exchanger is provided Heat conservation and Personnel protection insulation.

Equipment Description and Control

Hot Lean / Rich TEG Exchanger (HBG-2330) is a hairpin type heat exchanger constructed from carbon steel.

Table Operating and Design Conditions for HBG-2330

Temperature Monitoring, Control and ESD Instruments:

The heat exchanger is provided with the following local temperature indicator located on the inlet and outlet of the tube and shell inlet. These will be used to determine if fouling is occurring inside the heat exchanger and reducing the heat transfer efficiency:

Table HBG-2330 Temperature Monitoring

TEG Still Column (ZBE-2310)

In the TEG Still Column, rich TEG flows down through the packing, with reflux from the condenser, in countercurrent contact with vapors. As the glycol flows down the still, the water vapor rises and is vented to safe location. Rich TEG enters the TEG Reboiler (BBC-2310).

Equipment Description and Control

The TEG Still Column is placed vertically on top of the reboiler. It is a Stainless steel vessel with an outer diameter of 356 mm and height 3200 mm. The still has the following internal features:

Packing (Bulk)

Inlet Distributor

Table Operating and Design Conditions for ZBE-2310

TEG Reboiler (BBC-2310)

The reboiler supplies heat to regenerate the rich TEG flowing downs the still. The separation occurs due to the large difference in the boiling point of water and TEG. In the reboiler the rich TEG is heated to about 204°C and the water is removed as a steam vapor. At this temperature the TEG is regenerated, with minimum degradation, to a lean (dry) TEG phase with high purity. The TEG is fed from the reboiler to the Stahl Column to remove any residual water.

The TEG flows from the still over a distributor plate into the reboiler. The TEG is heated by two electric heaters (HZZ-2310A/B), and overflows to the stahl Column.

Equipment Description and Control

The TEG Reboiler is a horizontal Carbon Steel vessel. It has an inner diameter of 1067 mm and T/T length 3150 mm.

Table Operating and Design Conditions for BBC-2310

Level Monitoring, Control and ESD Instruments:

The reboiler is provided with the following TEG level sight glass and control instrumentation, level alarm and level trip instrumentation:

Table BBC-2310 Level Monitoring

The process variable from 10M-LT-2310-10 is used in the process shutdown logic system for activation of a low low and high high level alarms. Activation of the LALL-2310-10 trip settings will result trip of heater. LAHH-2310-10 will close the SDV-2215-1 glycol outlet from the glycol contactor. Refer to section 6.0 for the alarm trip settings.

Temperature Monitoring, Control and ESD Instruments:

The reboiler is provided with the following temperature, control, alarm and trip instrumentation:

Table BBC-2310 Temperature Monitoring

10M-TE-2310-12 is a temperature device; the process variable is used by transmitter 10M-TT-2310-12 to feed the controller 10M-TIC-2310-12. This controller will send a signal to the electric heater controllers to increase or decrease the temperature, dependant on the temperature from the reboiler. Low and high temperature alarms on this controller will alert the operator to Electrical heating problems in the reboiler.

10M-TAHH-2310-2 is used in the process shutdown logic system for the activation of a high high temperature alarm and trip the Glycol Reboiler Heater. Refer to section 6.0 for the alarm trip settings.

Pressure Monitoring, Control and ESD Instruments:

Reboiler is provided with a pressure indicator transmitter 10M-PIT-2310-8 with a process shutdown High High alarm. Activation of 10M-PI-2310-8 PAHH will result in the glycol re-boiler heater tripping and the closing of SDV-2215-1, contactor rich TEG outlet.

Table BBC-2310 Pressure Monitoring

Over-Pressure Protection:

Over-pressure protection of the reboiler is provided by pressure safety valve 10M-PSV-2310-6 set at 3.45 barg, relieving to the LP flare header. One PSV is required to meet the relief capacity of the reboiler.

STAHL Column (ZBE-2320)

The function of the Stahl Column is to remove residual water, by lowering water vapor partial pressure. To achieve this gas from the fuel gas supply is fed into the base of the stripper and contacted with the TEG overflowing from the reboiler counter-currently. The gas is pre-heated before entering the stripper by passing the line through the reboiler. Any water stripped out by the stripping gas flow is removed into the gas stream flows through the reboiler out of the still to the vent. The lean TEG from the Stahl Column is then fed to the two Glycol/Glycol heat exchangers for cooling and then to the surge drum for storage and reuse.

Equipment Description and Control

The Stahl Column is a random packing Carbon Steel vertical vessel. The Stahl Column has the following internal features. the column outer diameter is 273 mm and S/S length 2000 mm.

1" Pall Ring Random Packing

Inlet Distributor

Packing Support

Table Operating and Design Conditions for ZBE-2320

TEG Surge Drum (ABJ-2315)

The TEG is routed to the surge drum, via the two Glycol/Glycol heat exchangers HBG-2330 (shell side) and HBG-2335 (Shell side) from the Stahl Column. The Surge drum is covered in a personal protection covering due to the high temperatures. Any excess heat is lost from this tank to the atmosphere before the TEG is pumped back to the contactor.

Equipment Description and Control

The TEG Surge Drum is a horizontal Carbon Steel vessel. It has an inner diameter of 914 mm and T/T height 2540 mm.

Table Operating and Design Conditions for ABJ-2315

Level Monitoring, Control and ESD Instruments:

The surge drum is provided with the following level control, alarm and trip instrumentation:

Table ABJ-2315 Level Monitoring

The process variable from 10M-LT-2315-1 is used in the process shutdown logic system for activation of a low low & high high level alarm. Activation of the LALL trip will stop the TEG circulation pump. Activation of the LAHH will close SDV-2215-1, contactor rich TEG outlet valve. Refer to section 6.0 for the alarm trip settings.

TEG CIRCULATION Pumps (PBE-2325A/B)

The TEG circulation Pumps are required to pressurize the TEG up to slightly more than the pressure of the contactor for re-circulation of the TEG into the Contactor. The pumps feed into the Gas/Glycol Heat Exchanger. The pumps are rotary gear type pump. Each pump is fitted with a removable Y strainer on the suction pipework.

Equipment Description and Control

The TEG circulation Pumps are Carbon Steel positive displacement (Rotary Gear) pumps.

Table Operating and Design Conditions for PBE-2325A/B

Pressure Monitoring, Control and ESD Instruments:

The TEG circulation pump outlets are provided with the following pressure control, alarm and trip instrumentation:

Table PBE-2325A/B Pressure Monitoring

The process variable from 10M-PIT-2325A/B-2 is used in the process shutdown logic system for activation of both the high high and the low low-pressure alarms. Activation of the trip settings will result in a pump shutdown. Refer to section 6.0 for the alarm trip settings.

Over-Pressure Pump Protection:

Over-pressure protection of the outlet lines is provided by pressure relief valves 10M-PSV-2325A-3 and 10M-PSV-2325B-3 set at 63.78barg. Both PSV's relieve back to the TEG surge drum for high-pressure protection.

START UP, OPERATING & SHUTDOWN PROCEDURES - GLYCOL Regeneration

Cold Start-up Procedure Following a Planned Shutdown.

The following procedure details the steps to be undertaken to start-up the Glycol Regeneration systems following maintenance activities that may have involved piping intrusion works on part / all of the systems / subsystems.

This start-up procedure assumes that the system has been purged of all oxygen with an inert gas and that no explosive mixture exists within the system. Failure to do so may expose the Facility / personnel to unnecessary risks.

The following conditions are assumed to exist in executing this procedure: -

No Permits to Work are in force on any part of the system that may prohibit, or hinder, the safe start-up of the equipment.

The Fire and Gas Detection System, ESD Systems and control facilities within the PCR are operational including all alarms, trips and controllers.

All vents, purge points and manual sample points are closed and blanked, or capped off, where necessary.

Ancillary system requirements

The following ancillary systems must be available for operation prior to commencement of this procedure: -

Power is available to the skid

The instrument air system must be in operation.

The flash and booster gas compressors must be ready for operation.

The fuel gas supply system must be operational.

Flare and separation facilities are operational.

Cold Start-up Valve Checklist

Refer to the P&ID 's identified as pertaining to the relevant system whilst carrying out this procedure.

The system operator should check the system valves are in the positions detailed below.

Where valves are found to be out of position, the operator must satisfy himself it is safe to move the valve before doing so. This may involve referencing to an Isolation Permit or relevant Permit to Work.

Table Cold Start-up Valve Checklist

Note: PBE-2325A Considered as Duty pump and PBE-2325B as a stand by pump.

Cold Start-up Overrides

During the cold Start-up of the Glycol Regeneration system the following inputs to the shutdown system may require to be overridden at the Shutdown Panel in the Central Control Room until steady operating conditions are established:

Table Cold Start-up Overrides

Cold Start-up Procedure

Note: This procedure assumes that the system has had all oxygen removed and is under nitrogen blanket, which has been confirmed with manual measurements. Do not proceed with this procedure if this is not the case due to explosion hazards and degradation of the TEG in the presence of oxygen.

Table Cold Start-up Procedure Following a Planned Shutdown

Hot Start-up Procedure Following a Process Trip

The following hot start-up procedure details the steps to be taken to re-start the Glycol Regeneration system facilities following a system trip.

The procedure assumes all the facilities listed below have been operating normally but have shutdown as a result of a system trip or by manual initiation.

The reason for the shutdown has been investigated and rectified and it is considered safe to re-start the system.

The procedure assumes that the system is still O₂ free and that an explosive mixture has not accumulated within the system / piping.

The levels, pressures and temperatures within the Glycol Regeneration system are at or near normal conditions.

The following conditions are assumed to exist in executing this procedure: -

No Permits to Work are in force on any part of the system that may prohibit, or hinder, the safe start-up of the equipment.

The Fire and Gas Detection System, ESD Systems and control facilities within the CCR are operational including all alarms, trips and controllers.

It is assumed that in a short duration shutdown it is unlikely that spades or blinds would be moved, or drain and vent valves opened unless required to take corrective action on the cause of the shutdown. It is therefore unnecessary to recheck these items other than if they have been disturbed.

All vents, purge points and manual sample points are closed and blanked, or capped off, where necessary.

Communications have been established between all the personnel involved with the start-up procedure.

Safety/Briefing Meetings have been held with all directly concerned parties outlining the workscope and procedures.

The following Utility and Ancillary Systems are available:

Electrical Power Distribution

Instrument Air

Flash and booster gas compressors

Fuel gas system

Hot Start-up Procedure

During the Hot Start-up of the Glycol Regeneration System there should be no requirement to have any input over-ride to the shutdown system. Note 1 - Dependant upon the pressure remaining within the system, there may be the requirement to over-ride the TEG circulation pumps PALL 23225A/B-2 to enable a pump re-start. This will depend on the length of time that the pumps are shutdown, and at what trip point this switch is set at.

Note-2: This procedure assumes that the temperature of the system has not dropped significantly. It also assumes that the pressure in the system has not been lost through the opening of the blow down valve. This valve will open on an ESD and PSD in the event that this occurs the system will have to be repressurized following the cold start-up procedure.

Table Hot Start-up Valve Checklist

Note: PBE-2325A Considered as Duty pump and PBE-2325B as a stand by pump.

Table Hot Start-up Procedure Following a System Trip

Normal Operational Checks:

The normal operational conditions, together with alarm and trip set points for each item in the Glycol Regeneration System are provided in section 6.0.

On a regular basis the field operator should conduct the following routine checks:

Regularly line walk the system to visually inspect for leaks and noise from rotating equipment and other defects in the equipment such as leaking control valves and filter housings etc.- particular attention should be paid to any abnormal noise coming from the pumps.

Check all levels, pressures and temperatures in the rotating equipment and the process system.

Periodically conduct cross checks between the field instruments and the respective CCR controller indications to determine the accuracy of the instruments. Remedial action should be taken when significant discrepancies are noted.

Ensure the flash drum MBD-2350 pressure is steady between 3.0 barg and 3.3 barg on PI-2350-5 and the liquid level is steady on LG-2350-4.

Ensure that the lean TEG level in the surge drum as indicated by LG-2315-2 is at the desired level, between 50% and 60%.

Ensure that the TEG reboiler temperature is operated below 204 deg C to minimize the chances of TEG degradation. The temperature should be steady at the desired level as indicated by TI-2310-2.

Check the TEG reboiler pressure does not become excessive, as high reboiler backpressures can significantly reduce lean TEG concentration and dehydration efficiency. High backpressure may be caused by a partially plugged still column or packing stack.

TEG CONDITION - Take a sample of rich and lean glycol once a week and conduct the following testing:

o        Examine for finely divided precipitate. This normally contains iron products of corrosion (FeS and Fe₃O₄). This can lead to substantial operating problems within pumps and reboilers if allowed to accumulate to any degree. Good filtration practices should adequately cope with this problem.

o        Two-phase separation for condensate contamination. Possible causes are incorrect operation of production separator, glycol flash drum or carbon filter.

o        Check for thermal degradation. Usually can be determined by visual inspection of the TEG. If the sample appears darker and smells of burnt sugar it is an indication of degradation occurring. This can be the result of excessive reboiler temperatures.

o        Check the TEG for purity - i.e. Lean TEG purity should be ~99% with Reboiler temps of ~204 deg C and stripping gas utilized.

o        Check the TEG pH. The pH should be in the range of 6.0 to 6.2 for rich glycol and between 7.6 to 8.0 for lean glycol. Add M.E.A / T.E.A as required for pH control. High pH can cause the glycol to foam and be carried out the overhead line with the gas phase, resulting in excessive TEG losses. IF pH control chemical is added, it should be added slowly by means of a small dosing pump if possible whilst the TEG is circulating as opposed to a slug dose of the pH buffer.

On a routine basis check the Glycol Flash Tank (MBD-2350) interface for skimming of hydrocarbons. Start at the highest level first, followed by opening of the sample point, ensuring that the valve to the drains is closed. If Condensate appears at the sample point is evident, open the valve to the closed drains until the condensate is drained off. This may have to be continued to encompass the lower level valves until all the condensate is drained from the vessel. If condensate contamination is occurring into the TEG, the pressures within the flash drum will tend to increase as the condensate flashes to gas to the LP flare.

Regularly check the differential pressure on the carbon and TEG filters. If differential is not evident, this may indicate a holed filter or incorrect fitment of the elements. There should be some differential evident even with new filter elements installed.
When the differential pressure is high, this indicates that the filters are plugged and will require changeup. Most cartridge type filters can operate up to a differential pressure of ~ 1.72 barg, however reference should be made to the vendor data sheet for the filter's upper operating limits. Ensure the filter vessel is N2 purged prior to and after the filters are changed out. This has a dual effect benefit in that it removes any O2 from the system and prevents TEG oxidization, as well as leak testing the filter vessel static seals that may have been damaged when removing or refitting the vessel top domed section for access. If possible displace the TEG within the filter vessel back to the reboiler using N2 purge pressure prior to changing the filters as opposed to draining the vessel contents to drains. This saves on unnecessary consumption of TEG.

TEG filters should always be online whenever possible, otherwise contamination of the TEG will occur with resultant pump wear, and general contamination of the system. As only one filter bank is supplied, efforts should be made to limit filter downtime wherever possible.

Duty pump selection is to be reviewed weekly or as required by the Operations Supervisor.

Routine checks should be performed to collect level, pressure, pump deliverability and TEG composition data in order to ensure optimum operation of the glycol circulation pumps and pumping capacity is maintained. Regularly check the in-line suction strainers on the TEG circulation pumps for plugging. Low delivery pressure / rates can be caused by the suction strainer being fouled.

Check the glycol circulation pumps, pumping elements for leakage. Maintain the pump / splined drive coupling frame space for the correct lubrication level on a routine basis.

Monitor the differential temperatures on the hairpin heat exchangers to determine performance. If low efficiency occurs, the exchangers may require cleaning internally.

Planned Shutdown procedure

The following procedure details the steps to be taken to conduct a planned shutdown of the Glycol Regeneration System as part of an overall shutdown of the FPSO process facilities in preparation for inspection / maintenance activities.

The following conditions are assumed to exist in executing this procedure: -

Safety / Briefing Meetings have been held with all directly concerned parties outlining the workscope and procedures.

Communications have been established between all persons involved in this procedure.

o        No operations or Permits to Work are in force that may prohibit the shutdown of the system.

Note: When shutting down the Glycol Regeneration System the flash gas and booster compressors should be shut down at the same time, and gas will be sent to the HP Flare. This will leave the dehydration system pressurized and the glycol circulating through the regeneration system.

Table Planned Shutdown Procedure

Emergency Controlled Shutdown Procedure

The following procedure details the steps to be taken to conduct an emergency controlled shutdown of the Glycol Regeneration system.

Plant Status -The assumption is that an upset condition has occurred on the process or downstream facilities detected by the automatic shutdown systems, that requires the immediate controlled shutdown of the Glycol Regeneration system by the ESD system. There should be no cause for intervention by operators.

Table 32 Emergency Controlled Shutdown Procedure

Alarm, Trip and PSV Settings

Table Alarm, Trip & PSV Settings

Valve List

Table 34 Valve List

Acknowledgements

With my signature I do hereby acknowledge that I have read and understood the preceding document.