CHANGE CONTROL SHEET

BOOSTER GAS COMPRESSION

TABLE OF CONTENTS

Section-Page

1 Introduction 1-6

Purpose 

Scope 

References 

Definitions 

Responsibility 

2 Safety and Environmental Requirements 2-7

3 Process Overview  3-8

Major Equipment Summary

System Summary

4 Booster Gas Compression 4-10

Suction Scrubbers

Compressors 

Coolers 

Dew Point Control unit

5 Start-up, Operating & Shutdown Procedures - Booster Gas Compressors 5-30

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

6 Alarm, Trip and PSV Settings 6-56

7 7-61

8 Valve List  8-62

9 Acknowledgements  9-64

tables

Table 1 Operating and Design Conditions for MBF-2011A/B/C/D 

Table 2 Operating and Design Conditions for MBF-2021A/B/C/D 

Table 3 Operating and Design Conditions for MBF-2031A/B/C/D & MBF-2037A/B/C/D

Table 4 Pressure Monitoring-1^st Stage Inlet Scrubber 

Table 5 Pressure Monitoring-2^nd Stage Inlet Scrubber 

Table 6 Pressure Monitoring-3^rd Stage Inlet Scrubber 

Table 7 Level Monitoring-1^st Stage Inlet Scrubber 

Table 8 Level Monitoring-2^nd Stage Inlet Scrubber 

Table 9 Level Monitoring-3^rd Stage Inlet Scrubber 

Table 10 Temperature Monitoring-1^st Stage Inlet Scrubber 

Table 11 Temperature Monitoring-2nd Stage Inlet Scrubber 

Table 12 Temperature Monitoring-3^rd Stage Inlet Scrubber 

Table 13 Operating and Design Conditions for CBA-2010A/B/C/D 

Table 14 Operating and Design Conditions for CBA-2020A/B/C/D 

Table 15 Operating and Design Conditions for CBA-2030A/B/C/D & CBA-2031A/B/C/D

Table 16 1^st Stage Compressor Pressure Monitoring 

Table 17 2^nd Stage Compressor Pressure Monitoring 

Table 18 3^rd Stage Compressor Pressure Monitoring 

Table 19 Auxiliary Pressure Monitoring

Table 20 Auxiliary Level Monitoring

Table 21 Compressor Stage 1 Temperature Monitoring

Table 22 Compressor Stage 2 Temperature Monitoring

Table 23 Compressor Stage 3 Temperature Monitoring

Table 24 Auxiliary Temperature Monitoring

Table 25 Compressor Vibration Monitoring

Table 26 Auxiliary Flow Monitoring

Table 27 Operating and Design Conditions for HBG-2015A/B/C/D 

Table 28 Operating and Design Conditions for HBG-2025A/B/C/D 

Table 29 Operating and Design Conditions for HBG-2035A/B/C/D 

Table 30 1^st Stage Cooler Temperature Monitoring 

Table 31 2^nd Stage Cooler Temperature Monitoring 

Table 32 3^rd Stage Cooler Temperature Monitoring 

Table 33 1^st Stage Cooler Pressure Monitoring 

Table 34 2^nd Stage Cooler Pressure Monitoring 

Table 35 3^rd Stage Cooler Pressure Monitoring 

Table 36 Operating and Design Conditions for HBG-2045 

Table 37 Operating and Design Conditions for MBF-2046 

Table 38 Operating and Design Conditions for HZZ-2046 

Table 39 Dew Point Control Unit Pressure Monitoring

Table 40 Dew Point Control Unit Temperature Monitoring 

Table 41 Dew Point Control Unit Level Monitoring

Table 42 Dew Point Control Unit Flow Monitoring

Table 43 Pre Start-up Checklist

Table 44 Cold Start-up Valve Checklist

Table 45 Cold Start-up Overrides

Table 46 Cold Start-up Procedure Following a Planned Shutdown 

Table 47 Hot Start-up Valve Checklist

Table 48 Hot Start-up Procedure Following A System Trip 

Table 49 Planned Shutdown Procedure

Table 50 Manual Rotation Procedure

Table 51 Emergency Controlled Shutdown Procedure

Table 52 Alarm, Trip & PSV Settings

Table 53 Valve List

figures

Figure 1  Block Diagram of the Booster Gas Compression System 

Introduction

This document is part of the Operating Manual, which covers the Booster Gas Compression Facilities. The Booster Gas Compression Facilities together with other manuals and related documents comprise the Facility Management System or FMS. The Booster Gas Compression Facilities 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 Booster Gas Compression Facilities. 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 Booster Gas Compression Facilities on the Baobab 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 Booster Gas Compression Facilities.

References

P&ID No: 1072-MI20-9020-0112, 1072- MI20-9020-0113, 1072- MI20-9020-0116 & 1072- MI20-9020-0173,

Vendor P&ID No: 1072-2000-G12-005/WCPS-311-1101,

1072-2000-G12-006/WCPS-311-1102

1072-2000-G12-007/WCPS-311-1103

1072-2000-G12-008/WCPS-311-1104

Start-Stop Sequence Diagram (Doc No: 1072-2000-J01-0158/ WCPS-311-7183)

Cause & Effect Shutdown Matrix (Doc No: 1072-2000-J01-0021/ WCPS-311-7107)

Cooler Datasheet (Doc No: WCPS-311-3119)

Compressor Datasheet (Doc No: 1072-MI20-90DS-2000/01)

Definitions

See the Definitions Document No: xx(HOLD)

Responsibility

Every plant system covered by the Booster Gas Compression Facilities 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 (1072-MI20-15ST-0170) Manual.

Safety and Environmental Requirements

In the execution of the subsequent procedures all permit to work, PPE and isolation procedures required by the Baobab SMS 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.

Other safety precautions to be followed for operation of this system are:

Do not open bleed valves in block and bleed unless the system is depressurized. Block valves downstream of PSV's shall only be closed when the system is shutdown and de-pressured.

In case of shutdown and start-up, the system should be properly purged and tested. Proper isolation and purging procedures are to be followed before the equipment is released for maintenance.

Noise in the vicinity of the compressors, once on line will be high. Ear protection is to be worn in designated areas.

The compressor is designed for hydrocarbon gas. Nitrogen will adversely effect its performance. So nitrogen must be purged from the system before compressor start-up.

Excessively low system temperatures during pressurization can produce hydrates and effect the working of process piping due to cold embrittlement. So do not re-pressure the system if temperature is low during re-pressurization.

Blow down of gas to liquid drain may cause over pressurization and cooling of the system. When manually dumping / draining liquids to the closed drain do not allow gas to blow down the drain. Close the drain valve immediately as the sound of passing gas is heard.

As nitrogen is not a life support gas, care should be taken during purging, opening purged equipment and venting nitrogen.

Avoid causing trip Hazard when running out the flexible nitrogen hoses.

Process Overview

Major Equipment Summary

The booster gas compression facilities contain four compressors (trains) each with three stages. Each train has the following pieces of equipment:

First stage compressor suction scrubber MBF-2011A/B/C/D

First stage compressor CBA-2010A/B/C/D

First stage cooler HBG -2015A/B/C/D

Second stage suction scrubber MBF-2021A/B/C/D

Second stage compressor CBA-2020A/B/C/D

Second stage cooler HBG -2025A/B/C/D

Third stage suction scrubber MBF-2031A/B/C/D

Third stage suction scrubber MBF-2037A/B/C/D

Third stage compressor CBA-2030A/B/C/D

Third stage compressor CBA-2031A/B/C/D

Third stage Discharge cooler HBG -20 5A/B/C/D

Dew Point Control Unit contain the following equipment:

Dew Point Control Exchanger HBG-2045

Dew Point Control Scrubber MBF-2046

Import Gas Heater HZZ-2046

System Summary

There are four booster gas compressors/trains used to compress gas from the Flash Gas Compressor and HP Separators at a pressure of approximately 7 Barg to approximately 175 Barg. The compression is achieved in three stages, using reciprocating compressors. After 1^st Stage Compression the gas is sent to Dew Point Control Unit where the dew point of export gas is suppressed by throttling the gas & knocking out liquid from the gas. The dry gas is then sent to 2^nd Stage Compression. After 2^nd stage the gas is dried in the Gas Dehydration unit and sent to 3^rd stage. After 3^rd stage the gas is sent for gas lift & excess gas is exported to Espoir FPSO. See P&IDs 1072-MI20-9020-0112, 1072- MI20-9020-0113, 1072- MI20-9020-0116 & 1072-MI20-9020-0173 for this system.

Figure 1 Block Diagram of the Booster Gas Compression System

Booster Gas Compression

Gas from the HP Separators and the Flash Gas Compressor is piped to the four Booster Gas Compressors Trains (4x33%). The following is a description for one of the compressor trains. The other three compressor trains are identical with equal capacity.

The gas enters the first stage suction scrubber (MBF-2011A) and free liquids are removed from the gas stream. Liquids collected in the scrubber are discharged to the I. P. Separator (MBD-1125) . The gas then enters the first stage of the compressor(CBA-2010A).

First stage compression increases the gas pressure from 7.2 Barg at 32 C to 25.5 Barg at 135 C. Gas from the first stage compressor is cooled in the first stage after-cooler (HBG -2015A) to approximately 38 C. The gas is then sent to the HP fuel gas system and the Dew Point control Unit to ensure that Export gas Dew Point is less than or equal to 22.2 C for pressures between 31 and 38.6 Barg.

The gas from Dew Point control Unit is then routed to the second stage suction scrubber (MBF-2021A). In this scrubber the free liquids are removed from the gas stream. The liquids collected by this scrubber are routed to the first stage suction scrubber by level control valve 07M-LV-2021A-2.

Gas from the second stage scrubber is then routed to the second stage compressor (CBA-2020A). Second stage compression increases the gas pressure from 18.88 Barg to 58.10 Barg at 135 C. The compressed gas is cooled in the second stage after-cooler (HBG -2025A) to approximately 40 C. . The gas from 2^nd stage compressor discharge is Booster then routed to the Gas Filter Separator prior to undergoing dehydration by absorption in the Glycol Contactor, where the gas is dried. The dried gas then enters the third stage suction scrubbers (MBF-2031A & MBF-2037A) where again any free liquids remaining in the gas stream are removed. Collected liquids are sent to the second stage suction scrubber under level control valves 07M-LV-2031A-2 & 07M-LV-2037A-2 respectively. The 3^rd stage compressor (CBA-2030A & CBA-2031A) increases the gas pressure from 55.40 Barg to 173.40 Barg at 146 C. The gas is then cooled by the discharge cooler (HBG-2035A) to approximately 40 C. The compressed gas is sent to gas lift and to export risers as per requirements.

Dew Point Control Unit

Dew Point Control Unit consists of a Gas/gas Exchanger (HBG-2045), a Joule-Thompson Valve & a Liquid Knockout Drum (MBF-2046). Gas from 1^st Stage is cooled in HBG-2045, throttled through the Joule-Thompson valve & finally taken to MBF-2046 to knock out liquids present. Liquid accumulated in Scrubber is sent back to production separator under level control.

In case of gas import, Dew Point Control Scrubber (MBF-2046) acts as import gas receiver and import gas is routed from MBF-2046 to Fuel Gas skid via Import Gas Meter (ZZZ-2415). The Dew Point Control Scrubber is provided with Import Gas Heater (HZZ-2046) which is actually Immersion Heater Coil & is only functional during Gas Import Operation.

Suction Scrubbers

(MBF-2011A/B/C/D,MBF-2021A/B/C/D,MBF-2031A/B/C/D,MBF-2037A/B/C/D)

As mentioned the suction scrubbers are required for the removal of liquids in the gas stream. In each train there are four suction scrubbers one for 1^st stage of compression, one for 2^nd stage of compression, two for 3^rd stage of compression, located on the inlet to each stage. They are fitted with a vane / demister pack at the upper section of the vessel to allow any liquids in the gas phase to coalesce and form into larger liquid droplets. These will collect in the bottom of the scrubber and then be discharged from the scrubber under level control.

Equipment Description and Control

Table 1 Operating and Design Conditions for MBF-2011A/B/C/D

Table 2 Operating and Design Conditions for MBF-2021A/B/C/D

Table 3 Operating and Design Conditions for MBF-2031A/B/C/D & MBF-2037A/B/C/D

The suction scrubbers have the following control and instrumentation installed.

Pressure Monitoring, Control and ESD Instruments:

The scrubbers are provided with the following local pressure indicator, control, alarm and trip instrumentation:

Table 4 Pressure Monitoring-1^st Stage Inlet Scrubber

Table 5 Pressure Monitoring-2^nd Stage Inlet Scrubber

Table 6 Pressure Monitoring-3^rd Stage Inlet Scrubber

The pressure transmitter on the suction of the compressor will measure the suction pressure. If it is too low the recycle valve will open allowing spill back from the discharge of the compressor with the objective of increasing this suction pressure.

All of the transmitters with associated high high and low low pressure alarms are used in the shutdown logic system for the activation of these alarms. All of these alarms should produce a compressor trip and shut it down, depressurize by opening the blowdown valve and isolate by closing both the suction and discharge shutdown valves.

Level Monitoring, Control and ESD Instruments:

The scrubbers are provided with the following local level indicator, control, alarm and trip instrumentation.

Table 7 Level Monitoring-1^st Stage Inlet Scrubber

Table 8 Level Monitoring-2^nd Stage Inlet Scrubber

Table 9 Level Monitoring-3^rd Stage Inlet Scrubber

When the high level alarm on the scrubbers is activated an alarm will annunciate thereby informing the operator. The level control valve on the liquid outlet line to the I. P. Separator will maintain a Normal liquid level within the scrubber. This is to maintain a liquid seal in the lower section of the scrubber across the Level Control Valve to prevent gas blowby. The outlet line to the closed drains Header is normally closed and should only be used for draining the vessel for isolation purposes. The high high levels on all of the scrubbers should produce a compressor shutdown via the inbuilt shutdown logic.

Temperature Monitoring, Control and ESD Instruments:

The scrubbers are provided with the following local temperature indicator, control, alarm and trip instrumentation:

Table 10 Temperature Monitoring-1^st Stage Inlet Scrubber

Table 11 Temperature Monitoring-2nd Stage Inlet Scrubber

Table 12 Temperature Monitoring-3^rd Stage Inlet Scrubber

Over Pressure Protection

Over-pressure protection of the suction line, suction scrubber & pulsation bottle is provided by pressure safety valves

07M-PSV-2011A/B/C/D-8 set at 13.8 Barg for 1^st Stage Compression

07M-PSV-2021A/B/C/D-4 set at 29.3 Barg for 2^nd Stage Compression

07M-PSV-2031A/B/C/D-4 set at 63.8 Barg for 3^rd Stage Compression

All relieving to the HP flare header. Only one PSV is required to meet the relief capacity of each line.

Compressors

(CBA-2010A/B/C/D, CBA-2020A/B/C/D, CBA-2030A/B/C/D &CBA-2031A/B/C/D)

There are three compression stages all working in the same manner. The compressors are reciprocating and each stage is driven off a common crankshaft, via an electric motor as the prime mover. A reciprocating compressor is a positive displacement machine that uses a piston contained within a cylinder to produce compression. The piston traverses the cylinder, and the corresponding increase in cylinder volume, allows the suction pressure to fill the cylinder volume with gas at one end of its stroke, then compressing the gas when the piston reverses it's direction towards the other end of its stroke. Gas enters the cylinder through a suction valve at suction pressure and is compressed to reach discharge pressure. When the gas reaches discharge pressure, it is then delivered through a discharge valve. The suction and discharge bottles on the compressor cylinders are pulsation dampeners. These are designed to dampen out the naturally occurring pressure pulsations created by a reciprocating compressor.

Equipment Description and Control

Table 13 Operating and Design Conditions for CBA-2010A/B/C/D

Table 14 Operating and Design Conditions for CBA-2020A/B/C/D

Table 15 Operating and Design Conditions for CBA-2030A/B/C/D & CBA-2031A/B/C/D

Pressure Monitoring, Control and ESD Instruments:

The compressors are provided with the following local pressure indicator, control, alarm and trip instrumentation.

Table 16 1^st Stage Compressor Pressure Monitoring

Table 17 2^nd Stage Compressor Pressure Monitoring

Table 18 3^rd Stage Compressor Pressure Monitoring

The pressure transmitters located on the discharge of each compressor stage are used in the emergency shutdown logic system for the activation of the high high and low low alarms. Activation of the alarms should produce a compressor shutdown where the system should be isolated and then depressurized by the Shutdown logic (Ref :Cause & Effect Matrix & Start-stop Sequence Diagram))

AUXILLARIES: Pressure Monitoring, Control and ESD Instruments:

Table 19 Auxiliary Pressure Monitoring

AUXILLARIES: Level Monitoring, Control and ESD Instruments:

The compressors are provided with the following Level Indicator, control, alarm and trip instrumentation. On a breach of the Level Switch low, an alarm will annunciate alerting the operator of the low level.

On a activation of the Level Switch low low, the machine will be shutdown by the BGC control panel logic.

Table 20 Auxiliary Level Monitoring

Temperature Monitoring, Control and ESD Instruments:

The compressors are provided with the following local temperature indicator, control, alarm and trip instrumentation. The instrumentation listed in the following table is only for the first stage of the compressors. The following two stages have exactly the same instrumentation:

Table 21 Compressor Stage 1 Temperature Monitoring

Table 22 Compressor Stage 2 Temperature Monitoring

Table 23 Compressor Stage 3 Temperature Monitoring

The temperature elements located on the compressor are used in the emergency shutdown logic system for the annunciation of the high high temperature alarms. A breach of these trip setting will result in the shutdown, depressurization and isolation of the compressor.

AUXILLARIES: Temperature Monitoring, Control and ESD Instruments:

Table 24 Auxiliary Temperature Monitoring

Vibration Monitoring, Control and ESD Instruments:

Table Compressor Vibration Monitoring

AUXILLARIES: Flow Monitoring, Control and ESD Instruments:

.

Table Auxiliary Flow Monitoring

Over Pressure Protection

Over-pressure protection of the discharge of each stage of the compressor is provided by pressure safety valves 07M-PSV-2015A/B/C/D-3, 07M-PSV-2025A/B/C/D-2 and 07M-PSV-2035A/B/C/D-7 set at 29.3 Barg , 63.8 Barg, 193 Barg respectively, all relieving to the HP flare header. All the Relief valves are Pilot operated units. Only one PSV is required to meet the relief capacity of the discharge lines.

Coolers

(HBG-2015A/B/C/D, HBG-2025A/B/C/D, HBG-2035A/B/C/D)

The coolers located on the discharge of the compressor stages are required to cool the compressed gas to approximately 40 C. There is one cooler per stage. They are water cooled shell & tube heat exchangers.

Equipment Description and Control

Table 27 Operating and Design Conditions for HBG-2015A/B/C/D

Table 28 Operating and Design Conditions for HBG-2025A/B/C/D

Table 29 Operating and Design Conditions for HBG-2035A/B/C/D

The coolers have the following control instrumentation installed.

Temperature Monitoring, Control and ESD Instruments:

The coolers are provided with the following local temperature indicator, control, alarm and trip instrumentation.

Table 30 1^st Stage Cooler Temperature Monitoring

Table 31 2^nd Stage Cooler Temperature Monitoring

Table 32 3^rd Stage Cooler Temperature Monitoring

The discharge temperature at cooler outlet is controlled by the temperature control valve at cooling water outlet line of each cooler.

Pressure Monitoring, Control and ESD Instruments:

Table 33 1^st Stage Cooler Pressure Monitoring

Table 34 2^nd Stage Cooler Pressure Monitoring

Table 35 3^rd Stage Cooler Pressure Monitoring

Over Pressure Protection

07M-PSV-2015A/B/C/D-4, 07M-PSV-2025A/B/C/D-2 & 07M-PSV-2035A/B/C/D-4 are provided for protection 1^st, 2^nd & 3^rd stage coolers respectively, in case of Tube Rupture.

Dew Point Control unit

Dew Point control Unit comprises of following equipment:

Dew Point Control Exchanger (HBG-2045)

Dew Point Control Scrubber (MBF-2046)

Import Gas Heater (HZZ-2046)

Equipment Description and Control

Table 36 Operating and Design Conditions for HBG-2045

Table 37 Operating and Design Conditions for MBF-2046

Table 38 Operating and Design Conditions for HZZ-2046

The Dew Point Control Unit has the following control instrumentation installed.

Table 39 Dew Point Control Unit Pressure Monitoring

Table 40 Dew Point Control Unit Temperature Monitoring

Table 41 Dew Point Control Unit Level Monitoring

Table 42 Dew Point Control Unit Flow Monitoring

Over Pressure Protection

10M-PSV-2045-4 & 10M-PSV-2046-6 are provided on Dew Point Control Exchanger inlet & on Dew Point control Scrubber respectively. These are provided for the protection of the system when the unit has been shut-in and heated by a local fire.

Start-up, Operating & Shutdown Procedures - Booster Gas Compressors

Cold Start-up Procedure Following a Planned Shutdown

The following procedure details the steps to be undertaken to start-up the Booster Gas Compressors 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.

Ancillary system requirements

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

The HP separators should be operational supplying gas to the suction of the compressor.

Power is available to the compressors

Instrument air system is operational

The gas dehydration and TEG unit must be ready to process gas.

The Dew Point Control Unit must be ready to process gas.

The Cooling Medium Circulation system must also be operational.

A designated flow path should be available for the compressed gas - either to the nominated Baobab wells for gas lift or via the sales gas meter export line to Turret.

Prestart-up Checklist

Prior to starting the compressors the following checks must be completed to ensure the compressor is safely started.

Table 43 Pre Start-up Checklist

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.

Note: This cold start-up checklist will line compressor an out for operation.

Table Cold Start-up Valve Checklist

Cold Start-up Overrides

During the Cold Start-up of the booster gas compressor the following inputs to the shutdown system 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

This procedure should only be executed when there is gas available to the compressors i.e. the separators are operating at normal levels. One compressor at a time should be started, another one should not be started unless the first is stable and there is an excess of gas. Before executing this procedure the TEG regeneration unit should be circulating TEG at temperature and be ready to accept gas through the system

NB: For detailed procedure of Pre-lube Sequence, Purge Sequence & Start-up Sequence please refer 'Start-Stop Sequence Diagram (Document No: 1072-2000-J01-0158)'

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 Booster Gas Compressor 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 and temperatures in the Booster gas compressor 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/closed (moved from operating position) 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.

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

The following Utility and Ancillary Systems are available for operation:

The HP separators should be operational supplying gas to the suction of the compressor.

Electrical Power Distribution

Instrument Air

The gas dehydration and TEG unit must be operational and ready to take gas.

A designated flow path should be available for the compressed gas - either to the nominated Baobab wells for gas lift or via the sales gas meter export line to Espoir FPSO.

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

Hot Start-up Checklist

Refer to the P&ID'S identified for 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.

NB: For detailed procedure of Pre-lube Sequence, Purge Sequence & Start-up Sequence please refer 'Start-Stop Sequence Diagram (Document No: 1072-2000-J01-0158)'

Table Hot Start-up Valve Checklist

Hot Start-up Procedure

During the Hot Start-up of the Booster gas compressors there should be no requirement to have any input over-ride to the to the shutdown system.

Note: As with cold start-up the compressors should not be started unless the HP separators are operating under stable conditions. One compressor should be started at a time, and any excess gas will be directed to the flare system.

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 Booster Compressor System are provided in the system description.

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

Regularly line walk the system to visually inspect for leaks and other defects in the equipment - particular attention should be paid to strange noises or shaking in the compressor or piping.

Check that no gas is leaking from the stem seals / valve bodies on the SDV's, BDV and LCV's on the suction scrubbers.

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.

Check for any gas leakage from the cylinder head valve covers, this may be prevalent after the machine has been re-started and / or is coming up to operating temperature.

Regularly check the oil filter pressure gauges are reading within specifications.

The oil filter differential pressure should be below xx(HOLD) Bar. Regularly check to ensure that this condition is satisfied.

Ensure that the cylinder lubrication distributor block indicator pin is moving, and that the lubricator injection rate is set at the proper flow rate.

Regularly check the packing case injection oil rate and ensure it is at the correct rate. Note - this may need to be altered for break in of any new installed parts such as packings & rods.

Ensure that the packing water is flowing through the first and second cylinders on the First, Second & Third stage of the compressor.

Regularly check the lube oil pressure and temperature throughout the system. Monitor the lube oil pumps for any leaks at the mechanical seal when operating.

Regularly check the packing water pump discharge pressure and temperature. Check the pump mechanical seal elements for any leakage.

On a weekly basis / or as recommended by vendor, record the compressor head valve temperature on all cylinders, using a heat sensing instrument. Abnormal temperatures will indicate if any gas is passing through the suction and delivery valves.

On a regular basis, frame oil sampling should be undertaken and the sample analyzed for foreign metal particles and or dirt / moisture.

Regularly monitor the drive motor current.

Monitor the drive motor bearing lubricators (if fitted), ensure the correct grade and qty of oil is present within the lubricators.

Regularly check the packing vent / drain lines for abnormal temperature, by suitable means. An abnormal temperature will indicate a package case leakage. If a problem is found identify which cylinder is leaking.

Ensure that the scrubbers are dumping liquids as required.

Ensure that the lube oil tank is always at a suitable level.

Ensure that the lube oil sump is at a suitable level.

Visually inspect the motors. Rectify any problems immediately with the rotating equipment.

Refer to the Vendors specification manual for periods between overhauls and specific maintenance tasks pertaining to these models and service.

Planned Shutdown Procedure

The following procedure details the steps to be taken to conduct a planned shutdown of the Booster Gas Compressors 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:

No operations or Permits to Work are in force that may prohibit the shutdown of the Booster Gas Compressors.

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

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

Note: If all of the compressors are shut down the gas coming from the HP separators will be rerouted to the HP Flare.

NB: For detailed procedure of Planned Shutdown please refer 'Start-Stop Sequence Diagram (Document No: 1072-2000-J01-0158)'

Table Planned Shutdown Procedure

Compressor Manual Rotation After Shutdown

If the compressor is to be shutdown for a period longer than 24 hours hand rotation may be required which is outlined in the following procedure.

This is to prevent mechanical damage occurring to the compressor / main engine bearings from brinnelling and damage to the compressor crosshead shoes and piston rods (where they contact the cylinder packing case sealing rings) as a result of prolonged shutdown times whilst in the vicinity of rotating equipment.

This operation should be carried out once every 12-hour shift if possible.

Note: The gas compressor shall be shut down, electrically isolated and depressurized prior to commencing this operation.

This is to prevent unauthorized starting / uncontrolled rotation of the machine whilst operators are in close proximity of the machine / flywheel. Any residual pressure within the compressor cylinders may cause the unit to rotate faster or in the reverse direction other than planned during this operation.

Table Manual Rotation Procedure

Emergency Controlled Shutdown Procedure

The following procedure details the steps to be taken to conduct an emergency controlled shutdown of the booster gas compressors.

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 Booster Gas Compressors by the ESD system. There should be no cause for intervention by operators.

NB: For detailed procedure of Emergency Controlled Shutdown please refer 'Start-Stop Sequence Diagram (Document No: 1072-2000-J01-0158)'

Table 51 Emergency Controlled Shutdown Procedure

Alarm, Trip and PSV Settings

Table Alarm, Trip & PSV Settings

Valve List

Table 53 Valve List

Acknowledgements

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