Instrument Air And Plant Air

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

ASAB – 2 ASAB GAS DEVELOPMENT PHASE II PROJECT 5228

OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267

DOCUMENT CLASS: 2

EASTERN BECHTEL COMPANY LIMITED

THE DESIGN OR PART THEREOF CONTAINED IN THIS DOCUMENT WAS DEVELOPED FOR GASCO FOR THE PROJECT AND REMAINS THE PROPERTY OF GASCO. ALL EASTERN BECHTEL COMPANY LTD (EBCL) PROPRIETARY INFOTION OR UNDERLYING INTELLECTUAL PROPERTY UTILIZED IN THE CREATION OF THE DESIGN OR INFORMATION CONTAINED HEREIN SHALL REMAIN THE PROPERTY OF EBCL.

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16-1

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

This page records the revision status of this document. All previous issues are hereby superseded and are to be destroyed. NOTES: Revisions after Rev. 1 are denoted as follows: (a) By a vertical line in the right-hand margin adjacent to the revised text. The revision number is displayed adjacent to the right hand side of the revision line, or (b) By a triangle symbol for graphics, the revision number being denoted within the symbol positioned adjacent to the revision. (c) CHKD = Checked by Project Functional Manager, or nominee; DISC = (Corporate) Functional Manager, or designee; PD = EBCL's Project Director, or designee

REV

DATE

4 3

16 May 10 08 Nov 08

2 1

19 Oct 08 15 Jun 08

REASON FOR ISSUE

Issued for Implementation Re-issued for Implementation Issued for Implementation Issued for Review

DISC

APPROVED PD PMC

FL CBM

AMCI AMCI

MPH IR

CBM CBM

AMCI AMCI

IR IR

BY

CHKD

AJW M&H M&H M&H

GASCO

Signed (Initials)

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16-2

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

TABLE OF CONTENTS 16.1

OVERVIEW ....................................................................................................................................... 5

16.2

PROCESS DESCRIPTION .............................................................................................................. 6 16.2.1

Compressors ........................................................................................................................ 7 16.2.1.1 ASAB-1 Compressors ....................................................................................................... 7 16.2.1.2 ASAB-2 Compressors ....................................................................................................... 8 16.2.1.3 Load Shedding .................................................................................................................. 8

16.3

16.2.2

Plant Air Production .......................................................................................................... 9

16.2.3

Instrument Air Production ................................................................................................ 9

EQUIPMENT DESCRIPTION ...................................................................................................... 11 16.3.1

Air Compressors Inlet Air Filter/Silencer ...................................................................... 11

16.3.2

Air Compressors ............................................................................................................... 11

16.3.3

HP and LP Interstage Coolers ......................................................................................... 11

16.3.4

Lube Oil Reservoir ........................................................................................................... 12

16.3.5

Main/Auxiliary Lube Oil Pumps ..................................................................................... 12

16.3.6

Lube Oil Cooler................................................................................................................. 12

16.3.7

Lube Oil Filters ................................................................................................................. 13

16.3.8

After-Cooler/Separator .................................................................................................... 13

16.3.9

Plant Air Receiver............................................................................................................. 13

16.3.10 Instrument Air Dryers ..................................................................................................... 14 16.3.11 Instrument Air Receiver .................................................................................................. 14 16.4

OVERPRESSURE PROTECTION DEVICES ............................................................................ 14

16.5

UNIT CONDITIONING ................................................................................................................. 15

16.6

OPERATING VARIABLES AND CONTROLS .......................................................................... 17 16.6.1

Compressor Automatic Control ...................................................................................... 18 16.6.1.1 Starting and Stopping ...................................................................................................... 18 16.6.1.2 Pressure and Amperage Control ..................................................................................... 19

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16-3

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.6.2

Agreement No 13522801

Rev. 4

Compressor PLC Operation ............................................................................................ 19 16.6.2.1 16.6.2.2 16.6.2.3 16.6.2.4 16.6.2.5 16.6.2.6 16.6.2.7 16.6.2.8 16.6.2.9 16.6.2.10

16.6.3

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228

General Status Screen ..................................................................................................... 19 SETPT Screens 1 through 5 ............................................................................................ 20 History Screen ................................................................................................................. 22 Data Screen ..................................................................................................................... 22 Oil System Screen ........................................................................................................... 22 Mode Screen ................................................................................................................... 23 Test.................................................................................................................................. 24 Configuration .................................................................................................................. 24 Utility .............................................................................................................................. 24 Compressor Manual Control ........................................................................................... 24

Dryer Operation................................................................................................................ 24 16.6.3.1 Drying Sequence ............................................................................................................. 24 16.6.3.2 Regenerating Sequence ................................................................................................... 25 16.6.3.3 Switch Over Between Both Dryers ................................................................................. 25

16.6.4

Alarm and Trip Settings .................................................................................................. 26

16.7

SAFETY PRECAUTIONS ............................................................................................................. 30

16.8

PRE-STARTUP CHECKS ............................................................................................................. 30

16.9

INITIAL STARTUP ........................................................................................................................ 32

16.10 NORMAL STARTUP ..................................................................................................................... 32 16.11 NORMAL OPERATION ................................................................................................................ 34 16.12 NORMAL SHUTDOWN ................................................................................................................ 36 16.13 EMERGENCY OPERATING CONDITIONS ............................................................................. 36 16.14 REFERENCES ................................................................................................................................ 37 16.15 ATTACHMENTS ............................................................................................................................ 37

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16-4

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.1

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

OVERVIEW The Plant and Instrument Air System in ASAB-2 consists of the following equipment:           

Air Compressors 267-C-101A/B/S packages, which include the following:

Inlet Air Filters/Silencers 267-C-101A/B/S-F-002 Electric Motor Drivers 267-CM-101A/B/S Air Compressors 267-C-101A/B/S Stages 1, 2 and 3 Low Pressure Interstage Coolers 267-C-101A/B/S-E-002 Pressure Interstage Coolers 267-C-101A/B/S-E-003 Lube Oil Reservoirs 267-C-101A/B/S-V-101 Lube Oil Reservoir Heaters 267-C-101-A/B/S-H-001 Main/Aux Lube Oil pumps 267-C-101A/B/S-001A/S Lube Oil Coolers 267-C-101A/B/S-E-001 Lube Oil Filters 267-C-101A/B/S-F-001 

After-Coolers/Separators 267-C-101A/B/S-E-004



Plant Air Receiver 267-V-101



Instrument Air Receiver 267-V-102



Instrument Air Dryers 267-ME-101A/S

The integrated air system is made up of six air compressor trains, three new compressor trains in ASAB-2 and three existing trains in ASAB-1. The ASAB-1 and ASAB-2 air systems supply Instrument Air, Plant Air, and the Nitrogen Generation systems. The programmable logic controller (PLC) based control system is designed to operate in full Automatic mode. The air compressor and dryer units in the ASAB-2 Instrument Air and Plant Air Unit 267 have been integrated with the existing Instrument Air and Plant Air Unit 167 in ASAB-1. Three new Air Compressors 267-C-101A/B/S provide enough capacity for continuous and intermittent demands with a 25% design margin. Because these units are dependent on each other to meet varying demands, an understanding of both units is needed. The Plant and Instrument Air Receivers 267-V-101 and 267-V-102 remove entrained water from the compressed air supply. The receivers also provide enough capacity to meet varying air demands while reducing pressure surges. The new Plant Air Receiver and Instrument Air Receiver operate in parallel with the ASAB-1 Plant and Instrument Air Receivers. A portable air compressor can be connected to the ASAB-2 plant air system at various points in the system. The ASAB-2 plant air system has provisions for a fourth compressor.

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16-5

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.2

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

PROCESS DESCRIPTION The air systems within Unit 267 provide: 

Plant air to Nitrogen Generation Unit 268



Instrument air to ASAB-2



Plant air for maintenance in ASAB-2



Instrument Air and Plant Air for ASAB-1, if needed

The existing Plant and Instrument Air System in Unit 167 is cross-connected with the ASAB-2 Plant and Instrument Air Systems in Unit 267. The Instrument Air Dryer packages 267-ME-101A/S takes air from the common outlet header on the Plant Air Receivers. The Instrument Air Receiver is sized to provide enough air capacity for a safe shutdown of the ASAB-2 plant in case of a supply failure. Instrument air crossovers downstream of the Instrument Air Dryers and the Instrument Air Receiver allow ASAB-1 and ASAB-2 to support each other if a problem occurs in either plant. The crossovers between ASAB-1 and ASAB-2 have isolation valves that shall be locked open when the system is integrated. The new ASAB-2 Air Compressors have a typical range of operation (turndown) of 77 % to 100 % of the rated capacity. If the demand from a compressor is less than the minimum discharge capacity of the compressor (3,900 Nm³/hr) excess compressed air is produced, and the compressor's unloading valve will lift, venting air to atmosphere (blow off). The table below shows the capacity of the compressors in each unit. Table 16.2-2 shows the expected flow in various operating cases and the compressor lineup needed to handle the demand without lifting any unloading valves. Table 16.2-1: Compressor Capacities Plant

Type

Compressor Capacity Nm3/hr Each

Combined

ASAB-1

Screw

2,000

6,000

ASAB-2

Centrifugal

5,000

15,000

Total

21,000

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16-6

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

Table 16.2-2: Compressor Operating Lineup Operating Cases

1

2

3

4

Maximum ASAB-1 demand and normal ASAB-2 demand

Normal ASAB-1 demand and maximum ASAB-2 demand

Normal combined demand ASAB-1 and ASAB-2

Maximum combined demand ASAB-1 and ASAB-2

9,383

15,800

8,583

16,600

Operate 2 ASAB-2 Compressors

Operate 2 ASAB-2 Compressor and 3 ASAB-1 Compressor

Operate 2 ASAB-2 Compressor

Operate 3 ASAB-2 Compressor and 1 ASAB-1 compressor

Each compressor delivers approximately 4,692 Nm³/hr, no blow off.

All compressors on full capacity, no blow off

Each compressor delivers approximately 4,291 Nm³/hr, no blow off.

All compressors on full capacity, no blow off

Flow (Nm³/hr)

The table above indicates that all six compressors are never needed to meet the total air requirements of ASAB-1 and ASAB-2. This leaves a small reserve to cover maintenance and sparing requirements when starting the spare compressor. The existing air distribution headers remain the same size in ASAB-1, so their capacity remains fixed. The new ASAB-2 piping to the existing ASAB-1 header is sized to deliver the rated capacity of the three new compressors plus an additional identically rated future compressor. This meets the anticipated maximum demand for the ASAB-2 plant and still has sufficient spare capacity. Several additional interconnections between the ASAB-1 and ASAB-2 compressed air systems are installed at strategic locations. These headers are sized to meet the specific sub-system requirements. Isolation valves on the crossover lines shall be locked open so that both ASAB-1 and ASAB-2 header pressures float on the system. 16.2.1

Compressors

16.2.1.1

ASAB-1 Compressors Air compressors operation is based on electrical relay logic control system installed adjacent to the compressors skids. Each compressor is equipped with a separate control panel. The field control panels communicate by hard wire to the distributed control system (DCS) and the electrical substation motor control centre (MCC). These compressors are started and stopped automatically by the ASAB-2 DCS to meet demands. The control logic is designed to provide automated sequential start of compressors for plant requirements as follows:

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16-7

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)



COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

DCS is used for the following:

 Compressors main/first and second spare selection  Remote manual compressors start/stop 

Local control panel is used for the following:

 Automatic compressors start/stop  Automatic compressors load/unload  Automatic compressor protection trips 16.2.1.2

ASAB-2 Compressors In automatic operation, one of the ASAB-2 compressors is selected in the DCS as the main, or duty compressor. All the other compressors, including the ASAB-1 machines, are selected as standby 1, 2, 3, 4, and 5. The order that the standby machines starts is determined in the DCS based on the needed flow rate, and the run time needed to equalize the operating time of the machines to allow for maintenance. When a compressor is being serviced, the Local/Remote switch is placed in Local, and the machine cannot be started automatically. Refer to Section 16.6, "Operating Variables and Controls" for more details.

16.2.1.3

Load Shedding Automatic isolation valves on ASAB-2 ensure a minimum pressure of 5.0 barg is maintained in the common instrument air header. These valves must also be reset after activation from the DCS. If the plant air pressure falls below 6.5 barg, and one or more compressors are down for maintenance, then the valves close in the following sequence to maintain the air supply to the Instrument Air System. There is a one minute wait between each shedding action to allow pressure to recover and stabilise:





ASAB-2 Plant Air System



ASAB-1 Plant Air System, if the required pressure still has not been re-established



ASAB-1 Nitrogen Generation System

ASAB-2 Nitrogen Generation System A 



ASAB-2 Nitrogen Generation System S (ASAB-2 is given a higher priority. It is larger than the ASAB-1 system.)

ASAB-2 Instrument Air (ASAB-1 can operate without ASAB-2, but ASAB-2 cannot operate without ASAB-1.)

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16-8

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.2.2

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Plant Air Production The discharge from the air compressors is fed through the common header into the ASAB-1 and ASAB-2 Plant Air Receivers where entrained water is removed. The air flows to the ASAB-2 Plant Air distribution system through an isolation valve HV-100 at the outlet of the receiver. This valve is operated by Open/Close hand switch HS-100 and closes automatically on an Instrument Air low pressure signal at the ASAB-1 Instrument Air Receiver. This valve must be reset from the DCS. This ensures adequate Instrument Air for a safe shutdown, if needed. The plant air to the ASAB-2 Nitrogen Generation System is also shut off automatically in case of Instrument Air low pressure by HV-100 (on the inlet to Nitrogen Generating Unit A) and by HV-101 (on the inlet to Nitrogen Generating Unit S). These valves must also be reset from the DCS. The air flow, temperature and pressure are measured at various locations throughout ASAB-2 and are readable in the Control Room on the DCS panel. Continuous users for Plant Air are as follows:  

Nitrogen Generation: Plant Air to each Pressure Swing Adsorber (PSA) Unit for Nitrogen Generation

Miscellaneous Packages: Nominal allowance of 10 Nm³/hr per continuous user for two users

Intermittent users for Plant Air are as follows:

16.2.3



Utility Stations



Miscellaneous Packages

Instrument Air Production Feed to the Instrument Air Dryer is supplied from the common header downstream of ASAB-1 and ASAB-2 Plant Air Receivers. The feed passes through a set of pre-filters, then through the pressure swing adsorption (PSA type desiccant air dryers. Desiccant fines are removed in filters before the dried air enters the Instrument Air Receiver. From the Instrument Air Receiver, the air goes to the ASAB-2 Instrument Air Distribution System. Each dryer is made up of two towers, with one tower in use while the other tower is regenerating. Regeneration is automatic, heatless, and occurs in the following order: 

The tower to be regenerated is depressurised.

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16-9

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

 

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Dry air passes through the tower to remove any moisture.

The tower is pressurised for the next changeover.

The valve sequence for dryer changeover, depressurising, regenerating, and pressurising is automatic with manual capability using the local control panel. Continuous users for Instrument Air are as follows:





Control Valves: 1.6 Nm³/hr of Instrument Air required per valve. A factor of 15% is added to account for valve leakage.



Regeneration of Instrument Air Dryers, 267-ME-101A/S: Instrument Air demand (dry).



Booster Compressors 191/291-C-101, Gas Turbines, Vibration Probe Cooling, and Pulse Jet Filter Cleaning Sequence.



High voltage motor purge for Propane Compressors 141/241-C-201 and Acid Gas Compressor Motor 153-C-101S.



Miscellaneous Packages: 20 Packages x 10 Nm³/hr of air used for each package.

18% of continuous

Analyzer shelter and instrument panel purges.

Intermittent users for Instrument Air are as follows: 

On/Off Valves: 0.8 Nm³/hr of Instrument Air required per valve. A factor of 15% is used to account for leakage.



Additional: Start up requirements for 141/241-C-201 and 153-C-101S high voltage motor purge.



Additional: Instrument Air for Booster Compressors 191/291-C-101, Gas Turbine:

 On-line Water Washing  Control Valve Actuation 

Seal Gas Panel purge

A crossover is available downstream of the ASAB-2 dryers to access a common Instrument Air Header between the ASAB-1 and ASAB-2 systems. The Instrument Air Receiver provides about 30 minutes supply for the ASAB-2 normal demand, down to a minimum operating pressure of 3.5 barg. Thirty minutes is enough time to shut down the plant in a safe and orderly manner.

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16-10

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

16.3

EQUIPMENT DESCRIPTION

16.3.1

Air Compressors Inlet Air Filter/Silencer

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

The 99.9% efficient 5 micron single stage filtration of the filter is provided by a cylindrical filter element. The high efficiency filter elements are automatically cleaned using a pulse jet air cleaning system during air compressor operation. 16.3.2

Air Compressors There are three chilled water cooled, centrifugal air compressors 267-C-101A/B/S. Each is rated for 5,000 Nm3/hr. These are larger than the existing ASAB-1 screw-type compressors. All of the compressors are driven by electric motors. After initial compression, the air travels through the LP intercooler where heat and moisture are removed. After the air is cooled and dried, it enters the compressor's second stage and is further compressed. The air is then directed through a the HP intercooler. Finally, the air enters the compressor's third stage, where it is compressed to the design discharge pressure. The air leaving the third and final stage of compression is directed to the aftercooler / separator for final cooling and moisture removal and supplied to the Plant Air System. The compressor's integral lubrication system supplies oil to the compressor bearings and gears, while the Chilled Water System supplies cooling water to the intercooler and aftercooler tube bundles and the lube oil cooler. The programmable logic controller (PLC) automatically positions the inlet control valve to maintain the driver load (motor amperage) within acceptable limits. The unloading valve on the compressor discharge line is automatically positioned to maintain the design discharge pressure. Protective devices are implemented within the control system to automatically shut down the compressor if any of the operating parameters reach an unacceptable level. The compressors have the following characteristics: Inlet Pressure: Inlet Temperature: Normal Flow (0°C and 1.0133 bara): Discharge Pressure: Discharge Temperature: Driver Power: Speed:

16.3.3

Atm 5°C to 60°C 5,002 Nm3/hr 9.9 bara 77.5°C 760 kW 2,976 rpm

HP and LP Interstage Coolers The low pressure and high pressure interstage coolers 267-C-101A/B/S-E-002/003 are finned, shell and tube heat exchangers built into a single unit with two shells operating in parallel.

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16-11

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Cooling water (CW) flows through the six-pass tube bundle in each shell, with air from the HP stage flowing through one shell side and air from the LP stage flowing through the other. The coolers have the following characteristics: E-002 (shell 1 side—LP Air) Operating Pressure: E-002 (shell 1 side—LP Air) Operating Temperature in/out: E-002 (tube 1 side—CW) Operating Pressure: E-002 (tube 1 side—CW) Operating Temperature in/out: E-002 (shell 1 side—LP Air) Flow: E-002 (tube 1 side—CW) Flow: E-003 (shell 2 side—HP Air) Operating Pressure: E-003 (shell 2 side—HP Air) Operating Temperature in/out: E-003 (tube 2 side—CW) Operating Pressure: E-003 (tube 2 side—CW) Operating Temperature in/out: E-003 (shell 2 side—HP Air) Flow: E-003 (tube 2 side—CW) Flow: 16.3.4

1.35 barg 153.8°C/24.2°C 5 barg 13°C/26.8°C 6,806.9 kg/hr 27,866 kg/hr 5.04 barg 134.7°C/16.1°C 5 barg 13°C/20.8°C 6518.4 kg/hr 27, 891 kg/hr

Lube Oil Reservoir The Lube Oil Reservoirs 267-C-101A/B/S-V-001 are stainless steel tanks with an internal Gulf Oilcoat VT coating and a thermostatically controlled electric heater. It is vented through a mist eliminator.

16.3.5

Main/Auxiliary Lube Oil Pumps The Main Lube Oil Pumps 267-C-101A/B/S-P-001A are shaft driven from the compressor bull gear. The Auxiliary Lube Oil Pumps 267-C-101A/B/S-P-001S are electric motor driven. Both are horizontal, screw/gear pumps with mechanical seals. The pumps have the following characteristics:

Discharge Pressure: Rated Flow: Speed: Driver: 16.3.6

Main Shaft Driven 5.8 barg 6 m3/hr 2,976 rpm N/A

Auxiliary Motor Driven 5.8 barg 6 m3/hr 2,906 rpm 4 kW

Lube Oil Cooler The Lube Oil Coolers 267-C-101A/B/S-E-001 are single-pass shell and two-pass tube heat exchangers cooled by CW.

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16-12

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

The lube oil coolers have the following characteristics: Operating Pressure (shell side): Operating Temperature (shell side) in/out: Operating Pressure (tube side): Operating Temperature (tube side) in/out: Max/Min Temperature: Heat Removal Capacity: Normal Flow: 16.3.7

5.5 barg 74.4°C/48.9°C 5.0 barg 13°C/16.8°C 148.9°C/6.7°C 221,561 kcal/hr 5.0 m3/hr

Lube Oil Filters The Lube Oil Duplex Filters are stainless steel/glass fiber duplex filters. The filters have the following characteristics: Design Pressure: Max allowable DP (clean):

16.3.8

10.3 barg 0.2 bar

After-Cooler/Separator The After-Cooler/Separator is a shell and tube heat exchanger with CW on the tube side and third stage discharge air on the shell side. The after-cooler has the following characteristics: Operating Pressure (shell side): Operating temperature (shell side) in/out: Operating Pressure (tube side): Operating temperature (tube side) in/out: Max/Min Temperature: Heat removal capacity: Normal air flow: Normal water flow:

16.3.9

8.9 barg 77.5°C/25°C 5 barg 13°C/15.7°C 148.9°C/6.7°C 244,944 kcal/hr 6,192.3 kg/hr 28,847.5 kg/hr

Plant Air Receiver Plant Air Receiver 267-V-101 is a vertical vessel equipped with an internal mesh pad to minimize liquid entrainment. The receiver removes 250 micron water droplets in the air flow at system design pressure and flow. A float-type water trap is provided to automatically drain accumulated water from the receiver. The operator can also use a manual blowdown from the drain connection to remove accumulated water.

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

The vessel also has approximately two minutes buffer capacity for the plant air. Sizing of this vessel is based on the air density at a mean pressure of 6.5 barg (5 to 8 barg span) and a worst case system temperature of 60°C. 16.3.10

Instrument Air Dryers The package has two fully automatic, heatless-type dryer trains, each having two desiccant beds. One dryer is on stream while the second dryer is on standby. They are controlled to alternately cycle the compressed plant air flow through the desiccant-filled, drying bed, where the vaporous moisture content is adsorbed. One desiccant chamber in the dryer package is always on stream in a timed drying cycle throughout normal dryer operation. The opposite, off stream chamber is in a pressurised standby condition or a timed regeneration cycle for removal of the desiccant's previously adsorbed moisture content. The drying chambers contain sufficient desiccant to dehydrate the compressed air to 40°C outlet dew point at atmospheric pressure and full flow at 8 barg and 60°C. The dryer's fail-safe design feature provides continued air flow through one desiccant chamber if the control system's power supply is ever lost or interrupted. The dryers are controlled from the main DCS.

16.3.11

Instrument Air Receiver Instrument Air Receiver, 267-V-012 is a vertical vessel sized to provide about 30 minutes buffer capacity for the Instrument Air System. After 30 minutes, the air supply depletes to 3.5 barg. This is the minimum delivery pressure required to operate control valves at the farthest location from the receiver. Being downstream of the dryers, the receiver should not have any moisture or condensate present inside. If required, the operator can use a manual blowdown from the drain connection to remove any moisture accumulation.

16.4

OVERPRESSURE PROTECTION DEVICES Overpressure relief devices are provided throughout the Instrument and Plant Air systems to protect the equipment and piping if an overpressure event occurs. On the air systems, these devices exhaust to the atmosphere at safe locations. On the Compressor lubricating oil system, the relief devices return fluid back to the oil reservoir. The pressure safety valves on the cooling water system discharge to an open drain. The overpressure protection devices within Unit 267 and their pressure setpoints are shown in the table below.

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

Table 16.4-1: Overpressure Protection Devices/Pressure Setpoints

16.5

Tag No.

Set Pressure (barg)

PSV-101A/S PSV-106A/S PSV-600 PSV-601 PSV-650 PSV-651 PSV-602 PSV-603 PSV-652 PSV-653 PSV-502 PSV-509 PSV-510 TSV-508 TSV-509 PSV-532 PSV-539 PSV-540 TSV-538 TSV-539 PSV-562 PSV-569 PSV-570 TSV-568 TSV-569

10.5 10.5 10.5 10.5 10.5 10.5 10.5 10.5 10.5 10.5 .45 7.93 7.93 8.62 8.62 .45 7.93 7.93 8.62 8.62 .45 7.93 7.93 8.62 8.62

Location 267-V-101 267-V-102 267-ME-101A-F-001A 267-ME-101S-F-001B 267-ME-101A-F-002A 267-ME-101S-F-002B 267-ME-101A-V-001A 267-ME-101A-V-001B 267-ME-101S-V-001A 267-ME-101S-V-001B 267-C-101A 267-C-101A-P-001A Discharge 267-C-101A-P-001S Discharge 267-C-101A Cooling Water Supply 267-C-101A Cooling Water Return 267-C-101B 267-C-101B-P-001A Discharge 267-C-101B-P-001S Discharge 267-C-101B Cooling Water Supply 267-C-101B Cooling Water Return 267-C-101S 267-C-101S-P-001A Discharge 267-C-101S-P-001S Discharge 267-C-101S Cooling Water Supply 267-C-101S Cooling Water Return

Destination Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere Oil Reservoir Oil Reservoir Open Drain Open Drain Atmosphere Oil Reservoir Oil Reservoir Open Drain Open Drain Atmosphere Oil Reservoir Oil Reservoir Open Drain Open Drain

UNIT CONDITIONING Note: The procedures described in this manual should be taken only as an operating guide and may be subject to further development at site. Reference: Vendor Document No. A6EL1078-705, 25179-200-V1A-MCRA-00098, Operations Manual Volume 1 for detailed instructions Prior to initial startup, all precommissioning activities must be completed and the unit must be ready for operation as follows: 

Verify the following before initial startup of the Unit:

 All safety equipment is in place and is fully operable.

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

 All equipment has been pressure tested, inspected, cleaned, drained, and dried. Note: System leak testing is performed at maximum operating pressure using dry air.  The system has undergone a leak test.  All pipe work and equipment is at a slightly positive pressure of dry air.  All needed test equipment and special tools and facilities are available.  All rotating equipment and their associated drivers have been aligned, run in and lubricated as required, following the manufacturers' recommended procedures.  Temporary strainers are installed where specified and their locations are properly recorded.  Electrical power systems have been checked out and commissioned.  Power is available to all electric drivers, and all control systems and panels.  All instruments are calibrated, loop checked, and commissioned.  All sensing elements that were removed from pipe work before hydrostatic testing are reinstated.  All the DCS data links are operational.  All utilities have been commissioned, lined up and are ready for use at the unit battery limit, unless otherwise stated in this document.  All vendor equipment has been fully commissioned and operators are fully familiar with its use.  The system has been completely punch listed and all critical punch items have been completed.  Rotors are rotated according to vendor recommendations.  Lube oil flush (sample and test) has been performed according to vendor specifications.  All piping and electrical connections are secure.  All valves, controls, trip and safety devices on instrument and electrical control systems are functioning correctly.  The compressor drive shaft can be rotated by hand.  The rotational direction of the driver shaft is correct. 

Verify the following safety requirements are met before initial startup:

 Firefighting System and all firefighting equipment and facilities are available and operational

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

 Breathing air equipment is available.  Evacuation and Emergency Response procedures are established and team members have been briefed.  Communications for external interfaces and services are established.  All pressure safety valves are lined up correctly.  All temporary blinds are removed.  All other pressure relief devices (rupture discs, etc.) are installed correctly.  All personnel are fully briefed on the startup procedure and their responsibilities.  A blowoff pipe with silencer is installed at the Plant Air Receiver as a temporary discharge route for the air.  Any active alarms associated with any of the above systems have been investigated and cleared. 

Perform the following before initial startup of the Unit:

 Trash blow all associated piping.  Perform leak tests.  Flush lines and inspect PSVs.  Inspect sight glass on oil reservoir for proper level. Note: If the oil level drops below the bottom of the oil level sight gauge when the pump is operated, add oil to the midpoint of the sight gauge. 16.6

OPERATING VARIABLES AND CONTROLS The operating limits associated with Unit 267 are listed in Table 16.6-1. Reference: 2517-267-M0Y-0000-B0003; Cause and Effects Diagram Unit 267 Plant Air Compressors 153-C-101A/B/S Reference: Vendor Document, 25179-200-V1A-MCRA-00010, Cause and Effects Chart Plant Air Compressors 267-C-101A/B/S Table 16.6-1: Unit 267 Battery Limit Supply Distribution Conditions Operating Conditions Instrument Air – Minimum Instrument Air – Normal

Pressure (barg)

Temperature (°C)

4.2

5

7.0 – 7.5

25

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Pressure (barg)

Temperature (°C)

Instrument Air – Maximum

8.0

70

Plant Air – Minimum

5.0

5

7.0 – 8.0

25

8.4

60

Operating Conditions

Plant Air – Normal Plant Air – Maximum

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

There is no composition specification for Plant Air. 16.6.1

Compressor Automatic Control

16.6.1.1

Starting and Stopping The control logic is designed to control the system in fully Automatic mode. Operator intervention is minimal. The automatic sequence starts and stops the compressors to meet air demand. A standby compressor is started if an unscheduled trip of a running machine occurs, and rotates service of machines to equalize the operating hours. One ASAB-2 machine is started and designated as the duty compressor. All other machines are designated as standby, including the ASAB-1 machines. Each standby compressor is started sequentially if a 7.5 barg low pressure condition (PAL) exists for greater than five minutes or a 6.5 barg low-low condition exists for greater than 5 seconds. Based on a total flow signal that has been averaged over the last minute, the DCS determines whether the next standby to start is an ASAB-1 or ASAB-2 compressor. After starting, the DCS waits a preset period to allow the system to stabilise. If the low pressure condition still exists, the next standby compressor is started, and so on. The command to sequentially stop standby compressors is initiated by a 8.5 barg high pressure condition (PAH) that exists for greater than 15 minutes. After stopping, the DCS waits a preset period to allow the system to stabilise. If the high pressure condition still exists, the next standby compressor is stopped, and so on. The order of the standby start sequence is determined by the logic. The machine that has been out of service for the longest time has priority for the next start. When a machine is stopped, it is placed at the end of the rotation cycle. If a machine is taken out of the Automatic mode, such as for maintenance, it becomes unavailable for rotation. When it is put back in Automatic mode, it is placed at the end of the rotation cycle. When a machine is stopped, it is not available until after the motor cool down timer has timed out. The machine that has the longest run time is designated as the next machine to stop. The next machine in the logic is started and goes into service before the longest running machine shuts down.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.6.1.2

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Pressure and Amperage Control The inlet control valves are positioned to maintain the desired motor amperage. The unloading control valve is used to maintain the desired discharge pressure. The unloading valve opens to exhaust compressed air to atmosphere when the compressor output flow exceeds the system demand.

16.6.2

Compressor PLC Operation Reference: Installation, Operation, and Maintenance Manual, 25179-200-POA-MCRA-00001 Chapter 6, Control System for detailed instructions This section describes the operation of the PLC control system, the functions of the control components, and provides adjustment procedures for compressor setpoints, control components, and compressor protective devices. The PAP PLC control system is used to perform the following functions:





Regulate the inlet and unloading valves



Monitor the operating parameters



Provide alarm and trip indications



Sequence the startup and shutdown of the unit



Govern the different modes of operation



Store pertinent data

Provide hard-copy output of information via serial printer interface

Primary communication with the PLC is through the human-machine interface (HMI) liquid-crystal diode (LCD), touch-panel display on the front of the control panel. Commands for starting the compressor, selecting control modes, entering setpoints, acknowledging alarms, etc. are entered on the touch screen. 16.6.2.1

General Status Screen All actions performed from the PLC begin with the General Status Screen. All other screens are accessed through it. If the compressor experiences an alarm or trip condition, the PLC touch pad display automatically reverts to the General Status Screen. The following Operating Status messages appear in the upper left corner of the General Status Screen to inform the operator of various conditions: 

Pull Emergency Stop to Enable

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

 Indicates that the manual emergency Stop/Start button (located on the front of the control panel) is in the Disabled position  Changes the emergency Stop/Start button to the Pulled-out position to permit startup of the air compressor 

PAP Shutdown

 Indicates when the emergency Stop/Start button is changed to the Pulled-out position (The compressor can now be started.) 

Waiting to Autostart

 Indicates the PLC is in the Autostart mode waiting for the Autostart signal based on system air pressure. 

Confirm Start or Cancel

 Indicates the user has initiated a start sequence by pressing the Start heading 

Driver Accelerating

 Indicates the unit is starting up 

Coastdown

 Displays this message any time the driver shuts down Note: Restart is prevented until the coastdown timer expires. 16.6.2.2

SETPT Screens 1 through 5 There are five individual setpoint screens on the PLC system. These screens display various operating parameters along with tuning constants for surge detection, PI control, historical scan time, and adaptive increment control. ▲ CAUTION: Changing the compressor setpoints can cause compressor surges or bypass the protective devices. It can also result in severe mechanical damage. Listed below are the various setpoints found on the PLC setpoint screens: 

Discharge Air Pressure – The PLC control system uses the unloading valve to maintain this pressure at the discharge of the air compressor.



System Air Pressure Low – This setpoint determines the plant air pressure.



Minimum Motor Amps – This setpoint (along with the Maximum Motor Amps setpoint) determines the operating amperage range of the driver (motor). The MIN amps setpoint corresponds to the suction throttling horsepower of the unit.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4



Maximum Motor Amps – This setpoint (along with the Minimum Motor Amps setpoint) determines the operating amperage range of the driver (motor). The MAX amps setpoint corresponds to the design horsepower of the unit.



Inlet Valve Prop Band and Reset – These setpoints control the responsiveness of the inlet control valve.



Unloading Valve Prop Band and Reset – These setpoints control the responsiveness of the unloading control valve.



Valve Times (Inlet and Unloading) – These setpoints determine the closing speed of the inlet valve (in seconds) and the opening speed of the unloading valve in order to obtain a smooth unloading of the compressor during intermittent and dual mode operation.



Valve Position To Auto Unload – This setpoint determines the unloading valve position. A timer in the PLC software is initiated before unloading the compressor on intermittent or auto dual mode control.



Auxiliary Oil Pump Shutoff Pressure – This setpoint determines the oil pressure during startup of the compressor at which the auxiliary oil pump is permitted to shut off.



Oil Temp Start Permissive – The permissive start setpoint determines the oil temperature at which the compressor can be started. The PLC will not permit the compressor to start until this oil temperature is attained.



Surge DP/DT – These setpoints determine the sensitivity of the surge detection system. Surge is detected when a certain pressure drop (DP) occurs within a certain time period (DT).



Adaptive Control Increment – If compressor surge occurs, this setpoint determines the amount of incremental adjustment that the controls will move away from surge. Every time the compressor surges, the controls make an incremental change until compressor surge no longer exists or the maximum motor amperage is reached.



Surge Alarm Option – This setpoint determines whether the PLC system annunciates an alarm during Adaptive Control.



Suction Throttle Prop Band and Reset – These setpoints control the responsiveness of the inlet control valve during the throttling action.



Modbus Address – This setpoint is used to enter the correct modbus address when communicating with the user's DCS. The modbus option can be enabled or disabled from the setpoint screen as well.



Sequencer Address – This setpoint is used to enter the correct sequencer address when communicating with an external sequencer. The sequencer option can be enabled or disabled from the setpoint screen as well.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

 16.6.2.3

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4



10 Pt. Trip/Alarm Recording Time – If an alarm or trip condition occurs, the panel stores 10 sets of data prior to the alarm or trip occurrence. This setpoint determines the time interval between the 10 sets of stored data.



History Recording Time – This setpoint determines the frequency (time intervals) in which historical operating data is stored into the memory of the microcomputer.

Date and Time Set – This setpoint is used to enter the correct time and date into memory.

History Screen The PLC system offers the capability to examine and print stored operating data. Select the History heading located on the PLC General Status Screen to examine this information. The following options are displayed:





1-Trips – Displays the last 10 trips the compressor experienced



2-Alarm – Displays the last 10 alarms the compressor experienced



3-Printer – Used to print various data from the PLC control system



4-Trend Selection – Allows the user to trend up to eight compressor parameters in real time



5-Start – Displays the total number of times the compressor was started

6-Surge – Displays the total number of times the compressor has surged

At the Trend Selection Screen, performing a trend selection allows the user to trend up to eight operational parameters of the compressor in real time. 16.6.2.4

Data Screen Operating data, such as pressures, temperatures, and amperage, can be displayed on the PLC system. Although most of the crucial operating parameters are displayed on the general status screen during operation, this screen can be used to examine all of the operating data. Reference: Installation, Operation, and Maintenance Manual, 25179-200-POA-MCRA-00001 Chapter 6, Control System for a complete list of the data points available.

16.6.2.5

Oil System Screen The PLC Oil System Screen is a status screen for the oil system. This screen displays values that include the following: 

Inlet oil pressure



Inlet oil temperature

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

 16.6.2.6

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16



Oil reservoir temperature



Low and high speed vibrations

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Oil filter differential pressure

Mode Screen The PLC Mode Screen is accessed to manipulate the operation of the inlet valve or unloading valve (manual or automatic). This compressor has been factory programmed for manual start/stop and suction throttle control only. 

Manual Operation of the inlet control valve allows the operator to manually adjust the compressor inlet airflow, which in turn, affects the driver load (motor current).

Note: Unattended manual operation is not recommended since changes in the compressor inlet air temperature affect the driver load and compressor surge. Note: Manually closing the inlet control valve too far during compressor operation may result in compressor surge. 

Automatic operation of the inlet control valve allows the control panel to automatically adjust the driver load (motor current). The control panel automatically maintains the driver load at the setpoint.



Manual operation of the unloading control valve allows the operator to manually adjust the compressor discharge pressure.

Note: Unattended manual operation is not recommended since changes in the compressor inlet air temperature affect the driver load and compressor surge. Note: Manually closing the inlet control valve too far during compressor operation may result in compressor surge. 

Automatic operation of the unloading control valve allows the control panel to automatically adjust the compressor discharge pressure. The control panel automatically maintains the compressor discharge pressure at the setpoint.



The operator pushes the necessary keys and buttons to manually operate in Start/Stop mode for starting and stopping the compressor.



The Suction Throttle Control mode reduces the driver power consumption by throttling the inlet airflow when the plant air system demand is satisfied.

Note: The inlet valve throttles the airflow until a minimum amperage setpoint is reached. If the minimum amps setpoint value is too low while operating in Suction Throttle Control mode, the compressor may surge.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Note: If the plant demand continues to decrease, the unloading control valve modulates to maintain design discharge pressure. This compressor has been factory programmed for suction throttle control only. 16.6.2.7

Test The Test screens display the status of the digital input and output channels. They also allow testing of the auxiliary oil pump, alarm light, trip light, and horn.

16.6.2.8

Configuration There are several options within the Configuration screens. Three of the Configuration menus can be accessed only by FS-Elliott authorised personnel. These include Digital Setup Screens 1 and 2 and the Adjustable Service Screens. The user configurable options are changing of the engineering units and adjusting operational timers.

16.6.2.9

Utility The Utility screen displays information such as the customer unit number, compressor serial number, compressor run time, and compressor power-on time. The screen also provides the ability to toggle between English and Spanish text and the contrast adjustment tools.

16.6.2.10 Compressor Manual Control The operator has the option of taking machines out of automatic control. In Manual mode, the operator controls the machine. 16.6.3

Dryer Operation The dryers are controlled from the main DCS. Each stage of the drying and regeneration sequence is controlled automatically on a time basis.

16.6.3.1

Drying Sequence Note: During dryer startup, both desiccant chambers are simultaneously pressurised before the dryer's power supply is energised. During system pressurisation, the inlet switching valve KV600 remains in its last position. The repressurisation valve KV601 is open and closes as the drying chamber pressurises first and the standby chamber pressurises through the purge system. The purge exhaust valves KV602 and KV603 are closed by pilot gas pressure supplied through the de-energized solenoid valves SOL A/D. The gas flow exits the dryer through the outlet non return valves V5A/V6A to a closed outlet isolation valve. This valve is slowly Opened manually following dryer pressurisation.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

When the DSC registers equal pressure in both chambers with the system, the inlet switching valve KV600 switches to Left Chamber Drying if the valves are not already in that position. The dryer 267- ME-101A is now in a control system timed Left Chamber Drying Cycle. After the fixed drying time of 5 minutes, inlet switching valve KV600 redirects the flow of compressed air to the Right Chamber. This cycle continues as controlled by the DCS. 16.6.3.2

Regenerating Sequence Two seconds after the inlet switching valve KV600 has operated, left chamber exhaust valve KV602 is opened allowing the chamber to depressurise. To prevent the desiccant fluidising an automatic flow restricting valve FV605 controls the rate of depressurisation until the pressure has decade sufficiently for regeneration to begin. The compressed air is released to atmosphere via a silencer designed to reduce the noise level during this period and to meet the equipment noise specification. A controlled supply of dry air is taken from the Right Chamber via the purge control valve, Orifice FO1A, and non return valve V7A. The amount of air used is detailed in the dryer specification sheet. The dry air passes through the Left Chamber Desiccant Bed collecting the previously adsorbed moisture and releasing it to atmosphere via the left chamber exhaust valve KV602, flow restricting valve FV605, and the silencer. After a fixed regeneration period of 4.5 minutes, the left chamber exhaust valve KV602 is closed preventing the purge air from escaping to atmosphere. Two seconds later the repressurisation valve KV601 is opened and the Left Chamber is returned to system pressure. Changeover to Left Chamber Drying is via the inlet switching valve KV600 redirecting the flow and leaving the Left Chamber at pressure. After two seconds, the right chamber exhaust valve KV603 is opened allowing the chamber to depressurise. Depressurisation is controlled as described in the previous Left Chamber sequence. Regeneration and repressurisation of the Right Chamber is carried out in a similar way to the Left Chamber except that the purge flow is via non return valve V8A.

16.6.3.3

Switch Over Between Both Dryers When the differential pressure over the on stream dryer 267-ME-101A reaches a level of 0.7 barg, the transmitter generates a signal to the DCS. DCS will initiate a dryer switch over sequence to the second dryer 267-ME-101S. (This works also vice versa.) Valve sequence is as follows: 

An Alarm is initiated.



Valve HV651 opens.

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)



GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4



Dryer chambers of 267-ME-101S are pressurised through the purge piping and no return valves V7A and V8A.



Pressure transmitters PT653 and PT 654 measure the pressure in both the dryer chambers.



When PT 653 and PT654 detect a pressure which is 1 barg lower than the actual working pressure in dryer, 267-ME-101A valve HV650 opens.



Dryer 267-ME-101S is started.



When dryer 267-ME-101S is started, valves HV600 and HV601 are closed.

Dryer 267-ME-101A is now ready for manual depressurisation.

The same sequence will be following for dryer 267-ME-101S in drying mode and dryer 267-E-101A in Standby mode starting with opening valve HV601. 16.6.4

Alarm and Trip Settings Table 16.6.4-1 lists all the alarm and trip settings in Unit 267. Setpoints designated Level and H are alarm settings, setpoints designated LL and HH are trip settings. Refer to Unit 267 Cause and Effect Diagrams for an explanation of the trip functions.

Table 16.6.4-1: List of Unit 267 Alarm and Trip Settings All tag numbers are prefixed with 267 except where noted. Tag No.*

Description

Function

Setpoint

Unit

167-PAHH-128B

Instrument Air

Activates alarm and stops the standby compressor on increasing pressure

8.5

barg

167-PALL-128A

Plant or Instrument Air

Activates alarm and starts the standby compressor on decreasing pressure

7.5

barg

167-PALL-128C

Instrument Air

Activates alarm and starts the standby compressor on decreasing pressure – Initiates Instrument air system load (demand) shedding

6.5

barg

AAH-650

Instrument Air Dryer Outlet Dew Point

Activates alarm on increasing dew point

-20

ºC

AAHH-650

Instrument Air Dryer Outlet Dew Point

Activates alarm and open standby dryer inlet and outlet valves on increasing dew point

-15

ºC

FAH-105

Instrument Air Flow

Activates alarm on high flow from 267-V-102

TBD

m3/hr

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-26

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Tag No.*

Description

Function

Rev. 4

Setpoint

Unit

50.6

amps

IAH-500

Motor Current

Activates alarm on increasing motor current and used as input for inlet valve control with Compressor 3rd Stage outlet pressure

IAHH-500

Motor Current

Activates alarm on increasing motor current and trips the motor/compressor

LAH-100

Plant Air Receiver

Activates alarm on decreasing level

460.0

mm

LAH-105

Plant Air Receiver

Activates alarm on decreasing level

500.0

mm

LAL-501

Oil Reservoir Level

Activates alarm on decreasing level

127

mm

LALL-501

Oil Reservoir Level

Activates alarm on decreasing level, shuts off reservoir heater

TBD

mm

PA-100

Pressure Discrepancy Alarm

Activates alarm on increasing difference between indications

5

%

PAL-105

Instrument Air Header Pressure

Activates alarm on decreasing pressure

TBD

barg

PAL-501

Instrument Air to Control Valves and Seal Air

Activates alarm on decreasing pressure

PAL-514

Lube Oil Pressure to header

Activates alarm on decreasing pressure

1.4

barg

PALL-514

Lube Oil Pressure to header

Activates alarm on decreasing pressure and trips the motor/compressor

1.0

barg

PDAH-503

Inlet Filter/Silencer DP

Activates alarm on increasing DP

TBD

bar

PDAH-511

Duplex Lube Oil Filter DP

Activates alarm on increasing DP

.7

bar

PDAH-652

Instrument Air Dryer Differential Pressure

Activates alarm on increasing DP across the operating dryer

500

mbar

PDAHH-652

Instrument Air Dryer Differential Pressure

Activates alarm and open standby drier inlet and outlet valves on increasing DP across the operating dryer

561

mbar

TAH-121

Compressor 267-C-101 A/B/S Discharge Temp to 267-V-101

Activates alarm on increasing temperature

50

ºC

TAH-503

Motor Temperature

Activates alarm on increasing temperature

97

°C

TAH-504

Motor Temperature

Activates alarm on increasing temperature

97

°C

amps

barg

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-27

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Tag No.*

Description

Function

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Setpoint

Unit

TAH-505

Compressor Temperature

Activates alarm on increasing temperature

°C

TAH-506

Compressor Temperature

Activates alarm on increasing temperature

°C

TAH-507

Compressor Temperature

Activates alarm on increasing temperature

°C

TAH-508

Motor Temperature

Activates alarm on increasing temperature

70

°C

TAH-509

Motor Temperature

Activates alarm on increasing temperature

100

°C

TAH-510

Compressor 2nd Stage Inlet Temperature

Activates alarm on increasing temperature

°C

TAH-511

HP Intercooler Outlet Temperature

Activates alarm on increasing temperature

°C

TAH-512

Lube Oil Temperature to header

Activates alarm on increasing temperature

57

°C

TAHH-503

Motor Temperature

Activates alarm on increasing temperature and trips motor/compressor

100

°C

TAHH-504

Motor Temperature

Activates alarm on increasing temperature and trips motor/compressor

100

°C

TAHH-505

Compressor Temperature

Activates alarm on increasing temperature and trips motor/compressor

°C

TAHH-506

Compressor Temperature

Activates alarm on increasing temperature and trips motor/compressor

°C

TAHH-507

Compressor Temperature

Activates alarm on increasing temperature and trips motor/compressor

°C

TAHH-508

Motor Temperature

Activates alarm on increasing temperature and trips motor/compressor

75

°C

TAHH-509

Motor Temperature

Activates alarm on increasing temperature and trips motor/compressor

105

°C

TAHH-510

Compressor 2nd Stage Inlet Temperature

Activates alarm on increasing temperature and trips the compressor

38.3

°C

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-28

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Tag No.*

Description

Function

Rev. 4

Setpoint

Unit

TAHH-511

HP Intercooler Outlet Temperature

Activates alarm on increasing temperature and trips the compressor

27.2

°C

TAHH-512

Lube Oil Temperature to header

Activates alarm on increasing temperature and trips the motor/compressor

60

°C

TAL-512

Lube Oil Temperature to header

Activates alarm on decreasing temperature

21.1

°C

VAH-500X

Motor Vibration

Activates alarm on increasing vibration

88.83

m-p/p

VAH-500Y

Motor Vibration

Activates alarm on increasing vibration

88.83

m-p/p

VAH-501X

Motor Vibration

Activates alarm on increasing vibration

88.83

m-p/p

VAH-501Y

Motor Vibration

Activates alarm on increasing vibration

88.83

m-p/p

VAH-502X

Compressor Vibration

Activates alarm on increasing vibration

22.86

m-p/p

VAH-502Y

Compressor Vibration

Activates alarm on increasing vibration

22.86

m-p/p

VAH-503X

Compressor Vibration

Activates alarm on increasing vibration

22.86

m-p/p

VAH-503Y

Compressor Vibration

Activates alarm on increasing vibration

22.86

m-p/p

VAHH-500X

Motor Vibration

Activates alarm on increasing vibration and trips the compressor

88.83

m-p/p

VAHH-500Y

Motor Vibration

Activates alarm on increasing vibration and trips the compressor

88.83

m-p/p

VAHH-501X

Motor Vibration

Activates alarm on increasing vibration and trips the motor/compressor

88.83

m-p/p

VAHH-501Y

Motor Vibration

Activates alarm on increasing vibration and trips the motor/compressor

88.83

m-p/p

VAHH-502X

Compressor Vibration

Activates alarm on increasing vibration and trips the motor/compressor

30.48

m-p/p

VAHH-502Y

Compressor Vibration

Activates alarm on increasing vibration and trips the motor/compressor

30.48

m-p/p

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-29

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.7

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

VAHH-503X

Compressor Vibration

Activates alarm on increasing vibration and trips the motor/compressor

30.48

m-p/p

VAHH-503Y

Compressor Vibration

Activates alarm on increasing vibration and trips the motor/compressor

30.48

m-p/p

XA-501

Compressor 267-C-101A not running

Activate alarm and close Chilled Water Inlet valve

On/Off

XA-531

Compressor 267-C-101B not running

Activate alarm and close Chilled Water Inlet valve

On/Off

XA-561

Compressor 267-C-101S not running

Activate alarm and close Chilled Water Inlet valve

On/Off

ZAH-500

Compressor Axial Displacement

Activates alarm on increasing displacement

ZAHH-500

Compressor Axial Displacement

Activates alarm on increasing displacement and trips the motor/compressor

12.5

m m

SAFETY PRECAUTIONS 

Reference: Safeguarding Narrative, 25179-267-M0Y-0000-B0003



Reference: 2517-267-M0Y-0000-B0003; Cause and Effects Diagram Unit 267 Plant Air Compressors, 153-C-101A/B/S

The ASAB-2 Air Compressors are proprietary. Protection is provided within the proprietary package and includes the needed relief valves. See Section 16.4 for the detailed listing and location. The Plant Air Receiver, 267-V-101, is protected with a relief valve, PSV-101A/S, discharging to atmosphere at a safe location. The Instrument Air Receiver, 267-V-102 is protected with a relief valve, PSV-106A/S that discharges to atmosphere at a safe location. Relief valves PSV-602, PSV-603, PSV-652 and PSV-653 protect the Instrument Air Dryer Packages, 267-ME-101A/S. These relief valves discharge to the atmosphere at a safe location. 16.8

PRE-STARTUP CHECKS The following are general guidelines for normal pre-startup checks.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-30

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Reference: 25179-200-V1A-MCRA-00098, Vendor Document No. A6EL1078-705, Operations Manual Volume 1 for detailed instructions for compressor operation Reference: 25179-200-V1A-MVDI-00026, Vendor Document No. 5003594, O&M, Installation, Operation and Maintenance Manual for detailed instructions for dryer operation 

Verify the following utilities are operating properly:

 Instrument Air for operation of control valves and on/off valves  Electrical for Air Compressor motors and lube oil motors  Nitrogen for instrument panel purge  Chilled Water for Air Compressors and lube oil cooling  Lube Oil Skids to condition, cool, pressurise and filter lubricant required for the Air Compressor trains. 

Perform prestart function and trip checks.



Verify that Instrument Air Dryer Package columns are loaded with desiccant.



Verify all utilities are available:

 Electric power (for pumps, compressors, etc.)  Instrument air (from ASAB-1 crossover or temporary supply)  Nitrogen (from ASAB-1 crossover or temporary supply)





Safety detection and protection systems at normal status, including the Firewater System.



All process control systems are fully commissioned and in good working order.



All vent systems and relief systems are ready and available.



All instrumentation available and isolation valves are open.



ESD System has been tested and ready.



Hand valves are in their normal position.



All vents and drains are closed.



All startup and shutdown sequences have been checked.

Recheck all safety devices for readiness.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-31

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.9

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

INITIAL STARTUP The following is a general outline of the initial startup with the ASAB-2 Plant Air and Instrument Air Systems. Reference: 25179-200-V1A-MCRA-00098, Vendor Document No. A6EL1078-705, Operations Manual Volume 1 for detailed instructions for compressor operation Reference: 25179-200-V1A-MVDI-00026, Vendor Document No. 5003594- O&M, Installation, Operation and Maintenance Manual for detailed instructions for dryer operation The operating procedures for initial startup are as follows: 

Place lube oil system in service.



Check lube oil heaters turn on below 23°C and turn off above 38°C.



If the compressor is being started for the first time or the main oil pump has been repaired or replaced, prime the main oil pump.

 Remove the pipe plug from the suction side of the pump.  Fill the pump and suction line with oil.  Replace and tighten the pipe plug.

 16.10



Verify Chilled Water is in service and is lined up to compressors, 267-C-101A/B/S, including the lube oil coolers.



All motor systems and auxiliaries are functioning normally.

Proceed to Normal Startup.

NORMAL STARTUP The following is a general outline of the startup with the ASAB-2 Plant Air and Instrument Air Systems. Reference: 25179-200-V1A-MCRA-00098, Vendor Document No. A6EL1078-705, Operations Manual Volume 1 for detailed instructions for compressor operation Reference: 25179-200-V1A-MVDI-00026, Vendor Document No. 5003594, O&M, Installation, Operation and Maintenance Manual for detailed instructions for dryer operation 

Verify that the Chilled Water Unit 266 is in service and chilled water is circulating through the Air Compressor skids, as per design.



Verify that all air is vented from the Chilled Water circulation system.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-32

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Note: The Instrument Air isolation valves are to remain open to support the Unit 266 Chilled Water operation. 

Verify that the Plant Air isolation valves between ASAB-1 and ASAB-2 air headers are shut.



Open the ¾” drain upstream of the expansion joint on the suction line of the compressor. Once it has been that the drain is not passing condensation it should be closed prior to start-up to prevent unfiltered air being fed to the compressor.



Place one ASAB-2 Air Compressor in service manually by local push button or DCS selector switch.



Open the ¾” drain on the unloading silencer. Once the drain valve is not passing condensation it should be closed.



When the Plant Air system is pressurised, slowly place the ASAB-2 Instrument Air Dryers in service.



Vent the Air Dryers dry air outlet line to atmosphere until the required dew point of 25°C is obtained.



When the Instrument Air quality reaches the required dew point, slowly pressurise the ASAB-2 Instrument Air Receiver.



Close the dry air outlet line vent to atmosphere on the dryers.

Note: The following allows Instrument Air from ASAB-2 to combine with Instrument Air from ASAB-1 in the common header. 

When the Instrument Air Receiver is fully pressurised slowly open the Instrument Air isolation valve on the Instrument Air Receiver. Note: The following allows ASAB-2 Plant Air to combine with ASAB-1 Plant Air in the common header. 

When the Instrument Air service in the common header is stabilised, slowly Open the isolation valve on the ASAB-2 Plant Air Receiver 267-V-101.



The Air Compressor operating in the Manual mode should be switched to Automatic.

Note: Under automatic control, the compressors start in sequence and come online until the Instrument Air Receiver is fully pressurised. 

Nominate the required compressor online/spare sequence and allow additional Air Compressors to start.



Open the Plant Air supply valves to the ASAB-2 Nitrogen Generation Unit.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-33

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

Note: Nitrogen Generation Units can now be placed into service, one unit at a time. The ASAB-2 Plant Air to the remaining users can now be placed in service one at a time, as required. 16.11

NORMAL OPERATION The following are general guidelines for normal operation. Reference: 25179-200-V1A-MCRA-00098, Vendor Document No. A6EL1078-705, Operations Manual Volume 1 for detailed instructions for compressor operation. Reference: 25179-200-V1A-MVDI-00026, Vendor Document No. 5003594, O&M, Installation, Operation and Maintenance Manual for detailed instructions for dryer operation. During normal operations, the pressure control system for the Instrument and Plant Air system continuously load and unload the two duty compressors to meet demands. If the pressure in the Plant Air Receiver falls below 6.5 barg due to failure of an on-line machine or low-low pressure in the Plant Air Header, the standby compressor starts automatically. The compressor control system also provides enough flexibility to meet demands from 0% to maximum design without operator action. The Air Compressors are motor driven multistage machines with water cooled inter and after coolers. Any water condensed in these coolers is automatically drained by drain traps to the open drain system. The flow of air to the plant air system is displayed on the DCS. If the Instrument Air header pressure falls below 6.5 barg, the following occurs:





The standby air compressor starts.



An on/off valve isolates the air supply to the Plant Air Distribution and the Interruptible Instrument Air Systems.

All available air is diverting to the Instrument Air System.

The Plant Air supply to the Instrument Air Header is regulated by the demand from the plant wide Instrument Air users. The air compressors supply three sub-systems:





Plant Air Header



Nitrogen Generation

Instrument Air Header

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-34

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

Separately isolatable headers are specified for ASAB-1 and ASAB-2. If there are upsets in the Instrument or Plant Air Systems, the following hierarchy of users applies:





ASAB-1 Instrument Air System takes priority over ASAB-2 Instrument Air System.



ASAB-2 Nitrogen Generation System takes priority over the smaller ASAB-1 Nitrogen Generation System.

ASAB-1 Plant Air System takes priority over the ASAB-2 Plant Air System.

If a major air leak which could lead to loss of the ASAB-1 Instrument Air supply is identified on ASAB-2, all common header isolation valves must be closed manually to preserve ASAB-1 operation. The ASAB-1 and ASAB-2 Air Compressors continuously load and unload to maintain the Instrument and Plant Air System operating pressures on the integrated ASAB-1 and ASAB-2 systems. Both the ASAB-1 and ASAB-2 plant are subject to fluctuations in demand. Typical operation of all six compressors will ideally sequence the duty and standby compressors. This balances operating time and number of starts and stops for each machine. The Operator selects the next on-line or off-line compressor, with the option of selecting individual compressors as in or out of service. During normal operation, inspect the following regularly to verify the optimum performance of the Unit: 

Instrument Air Dryer Package outlet pressure at 267-PIC-203 (should be 8.6 – 7.0 barg).



Check the liquid level in 267-V-102 on 267-LI-100.



Check that the moisture content of the air leaving the Air Dryer Package is meeting the dew point requirement (25°C at atmospheric pressure) as follows:  Monitor the On-line Analyser 267-AI-235.  Verify the monitor reading by sampling from sample connection, 267-SC-138.



During periods of high ambient humidity the drain on the unloading silencer should be regularly opened on all three compressors (running and standby) to ensure condensation does not build up in this line.



The drains on the suction lines of the standby machines should be opened regularly to prevent condensation build up in these lines.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-35

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

16.12

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4

NORMAL SHUTDOWN Note: The shutdown philosophy is normally the reverse of the startup operation. The following are general guidelines for a normal shutdown. Reference: 25179-200-V1A-MCRA-00098, Vendor Document No. A6EL1078-705, Operations Manual Volume 1 for detailed instructions for compressor operation. Reference: 25179-200-V1A-MVDI-00026, Vendor Document No. 5003594, O&M, Installation, Operation and Maintenance Manual for detailed instructions for dryer operation. 

Isolate the ASAB-2 Plant Air users one at a time.



Shut down the Nitrogen Generation Units, one unit at a time. Allow time between shut down of the first and second units for the air system to stabilize.



Isolate Plant Air supply line to Nitrogen Generation Units.



Close the ASAB-2 Plant Air isolated valves to the common header.

Note: ASAB-1 is now in complete control of the Plant Air system and only ASAB-1 is a user. ASAB-2 Plant Air production is supporting only the Instrument Air System. 

If Instrument Air is not needed in ASAB-2, give the Stop command to the Air Compressors.

Note: The compressors go through the automatic normal shutdown. 

After the compressor shutdown, close the Instrument Air isolation valves to the common header with ASAB-1.

Note: Support systems can remain in service or be shut down as required. 16.13

EMERGENCY OPERATING CONDITIONS Reference: Emergency Shutdown Philosophy, 25179-000-M0Y-0000-B0002 If a major air leak is identified on ASAB-2 which could lead to loss of the ASAB-1 Instrument Air supply, close all Instrument Air common header isolation valves to preserve ASAB-1 operation. If an upsets in the Instrument and Plant Air systems occurs, perform the following: Note: ASAB-1 Instrument Air has priority over ASAB-2. When ASAB-2 Instrument Air is isolated from ASAB-1, ASAB-1 Nitrogen Generation goes offline. The two Nitrogen Generation Units in ASAB-2 remain in service due to their larger capacity.

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-36

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

GASCO PROJECT NO. 5228 Agreement No 13522801

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

Rev. 4



Isolate ASAB-2 Instrument Air from the common header with ASAB-1.



If Plant Air supply continues to decline, take one of the ASAB-2 Nitrogen Generation trains offline, leaving one in production.



If the Plant Air supply does not stabilise, take the second ASAB-2 Nitrogen Generation train offline.

Note: ASAB-1 Plant Air has priority over ASAB-2 Plant Air.  16.14

REFERENCES



16.15

If the Plant Air supply continues to decline, without stabilising, isolate ASAB-2 Plant Air from the common header.



Safeguarding Narrative, 25179-267-M0Y-0000-B0003.



Cause and Effects Diagram Unit 267 Plant Air Compressors, 153-C-101A/B/S, 2517-267-M0Y-0000-B0003,



Vendor Document, 25179-200-V1A-MCRA-00010, Cause and Effects Chart Plant Air Compressors, 267-C-101A/B /S.



Vendor Document No. A6EL1078-705, 25179-200-V1A-MCRA-00098, Operations Manual Volume 1



Alarm Setpoints; (When assigned to InfoWorks)



Heat & Material Balance; 999-ZA-D-3598



Vendor Document; 25179-200-V1A-MCRA-00089



Emergency Shutdown Philosophy, 25179-000-M0Y-0000-B0002



Utility Flow Diagram, 267-GD-B-03519



Block Flow Diagram, 999-GD-B-03256



Unit 267 – Overall Utilities Summary, 999-ZA-E-03423



Utility Safeguarding Flow Diagram, GG-B-03631

Cause & Effect Chart, 25179-200-V1A-MCRA-00010

ATTACHMENTS 25179-130-M60-0000-F0201

Piping and Instrument Diagram – Unit 130 – Nitrogen and Plant Air and Instrument Air Distribution Absorber

25179-130-M60-0000-F0210

Piping and Instrument Diagram – Unit 130 – Nitrogen and Plant Air and Instrument Air Distribution

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

16-37

ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

25179-131-M60-0000-F0201

Piping and Instrument Diagram – Unit 131 – Nitrogen and Plant Air and Instrument Air Distribution

25179-141-M60-0000-F0111

Piping and Instrument Diagram – Unit 141 – Regeneration Gas Heater Train 1

25179-141-M60-0000-F0127

Piping and Instrument Diagram – Unit 141– Turbo Expander Train 1

25179-141-M60-0000-F0201

Piping and Instrument Diagram – Unit 141– Nitrogen and Plant Air and Instrument Air Distribution

25179-141-M60-0000-F0301

Piping and Instrument Diagram – Unit 141 – Regeneration Compressor Auxiliaries 141-C-107A

25179-141-M60-0000-F0302

Piping and Instrument Diagram – Unit 141 – Regeneration Compressor Auxiliaries 141-C-107S

25179-141-M60-0000-F0303

Piping and Instrument Diagram – Unit 141 – Turbo Expander – Comp. Seal Gas Conditioning Skid

25179-141-M60-0000-F0304

Piping and Instrument Diagram – Unit 141 – Refrigeration Compressor Auxiliaries 141-C-201

25179-145-M60-0000-F0201

Piping and Instrument Diagram – Unit 145 – Nitrogen – Plant and Instrument Air Distribution

25179-145-M60-0000-F0301

Piping and Instrument Diagram – Unit 145 – Stripper Overhead Compressor Auxiliary Stages 1 and 2 Train A

25179-145-M60-0000-F0302

Piping and Instrument Diagram – Unit 145 – Stripper Overhead Compressor Auxiliary Stages 1 and 2 Train S

25179-153-M60-0000-F0201

Piping and Instrument Diagram – Unit 153 – Nitrogen and Plant Air and Instrument Air Distribution

25179-153-M60-0000-F0301

Piping and Instrument Diagram – Unit 153 – Acid Gas Compressor Auxiliaries – Train A

25179-153-M60-0000-F0302

Piping and Instrument Diagram – Unit 153 – Acid Gas Compressor Auxiliaries – Train B

25179-153-M60-0000-F0303

Piping and Instrument Diagram – Unit 153 – Acid Gas Compressor Auxiliaries – Train S

25179-191-M60-0000-F0201

Piping and Instrument Diagram – Unit 191– Nitrogen and Plant Air and Instrument Air Distribution

25179-191-M60-0000-F0301

Piping and Instrument Diagram – Unit 191– Booster Compressor Auxiliary Train 1

25179-191-M60-0000-F0302

Piping and Instrument Diagram – Unit 191– Booster Compressor Auxiliary Train 1

25179-226-M60-0000-F0201

Piping and Instrument Diagram – Unit 226 – Nitrogen – Plant Air and Instrument Air Distribution

25179-230-M60-0000-F0201

Piping and Instrument Diagram – Unit 230 – Nitrogen plant Air and Instrument Air Distribution – Absorber

25179-230-M60-0000-F0210

Piping and Instrument Diagram – Unit 230 – Nitrogen Plant Air and Instrument Air Distribution – Regenerator

25179-241-M60-0000-F0111

Piping and Instrument Diagram – Unit 241– Regeneration Gas Heater Train 2

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

25179-241-M60-0000-F0127

Piping and Instrument Diagram – Unit 241–Turbo Expander Train 2

25179-241-M60-0000-F0201

Piping and Instrument Diagram – Unit 241– Nitrogen Plant Air and Instrument Air Distribution

25179-241-M60-0000-F0301

Piping and Instrument Diagram – Unit 241 – Regeneration Compressor Auxiliaries 241-C-107A

25179-241-M60-0000-F0302

Piping and Instrument Diagram – Unit 241 – Regeneration Compressor Auxiliaries 241-C-107S

25179-241-M60-0000-F0303

Piping and Instrument Diagram Unit 241 – Turbo Expander – Compressor Seal Gas Conditioning Skid

25179-241-M60-0000-F0304

Piping and Instrument Diagram – Unit 241 – Refrigeration Compressor Auxiliaries

25179-261-M60-0000-F0103

Piping and Instrument Diagram – Unit 261 – Sand Filtration Package

25179-261-M60-0000-F0104

Piping and Instrument Diagram – Unit 261 – Water Demineralization Package

25179-261-M60-0000-F0112

Piping and Instrument Diagram – Unit 261 – Water Chlorination Package

25179-261-M60-0000-F0202

Piping and Instrument Diagram – Unit 261 – Instrument Air and Plant Air

25179-262-M60-0000-F0106

Piping and Instrument Diagram – Unit 262 – Utility Boilers 262-FH-251A and B

25179-262-M60-0000-F0118

Piping and Instrument Diagram – Unit 262 – Utility Boilers 262-FH-251C and S

25179-262-M60-0000-F0204

Piping and Instrument Diagram – Unit 262 Nitrogen – Instrument Air and Plant Air

25179-264-M60-0000-F0101

Piping and Instrument Diagram – Unit 264 – Methanol Drum and Transfer Pumps

25179-264-M60-0000-F0201

Piping and Instrument Diagram – Unit 264 – Propane Area – Nitrogen – Plant Air and Inst. Air Distribution

25179-264-M60-0000-F0207

Piping and Instrument Diagram – Unit 264 – Methanol Area – Nitrogen – Plant and Instrument Air Distribution

25179-265-M60-0000-F0201

Piping and Instrument Diagram – Unit 265 Nitrogen – Plant Air and Instrument Distribution

25179-266-M60-0000-F0101

Piping and Instrument Diagram – Unit 266 Refrigeration Compressor Package – CHW System

25179-266-M60-0000-F0103

Piping and Instrument Diagram – Unit 266 Refrigerant Air Cooler – CHW System

25179-266-M60-0000-F0202

Piping and Instrument Diagram – Unit 266 Instrument Air – Nitrogen and Plant Air

25179-267-M60-0000-F0101

Piping and Instrument Diagram – Unit 267 Air Compressor

25179-267-M60-0000-F0102

Piping and Instrument Diagram – Unit 267 Plant Air Receiver

25179-267-M60-0000-F0103

Piping and Instrument Diagram – Unit 267 Instrument Air Dryer and Receiver

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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ASAB-2 OPERATING MANUAL CHAPTER 16 INSTRUMENT AIR AND PLANT AIR UNIT 267 ABU DHABI GAS INDUSTRIES LTD. (GASCO)

COMPANY DOC. 999-ZX-E-09060-C16 DOC. NO. 25179-000-GPP-GSX-00011c16

GASCO PROJECT NO. 5228 Agreement No 13522801

Rev. 4

25179-267-M60-0000-F0201

Piping and Instrument Diagram – Unit 267 Chilled Water Plant Air Utility Water and LP Steam Distribution

25179-268-M60-0000-F0101

Piping and Instrument Diagram – Unit 268 Nitrogen Generation Unit

25179-271-M60-0000-F0103

Piping and Instrument Diagram – Unit 271 – Low Temperature Flare 271-ME--101

25179-271-M60-0000-F0105

Piping and Instrument Diagram – Unit 271 – Warm – Acid Gas Flare 271-ME-102

25179-271-M60-0000-F0201

Piping and Instrument Diagram – Unit 271 – Nitrogen and Instrument Air Distribution

25179-273-M60-0000-F0106

Piping and Instrument Diagram – Unit 273 – Deluge Systems

25179-274-M60-0000-F0208

Piping and Instrument Diagram – Unit 274 – Non-Process Buildings Interfaces

25179-277-M60-0000-F0111

Piping and Instrument Diagram – Unit 277 – BFW – Steam and Condensate Systems

25179-277-M60-0000-F0112

Piping and Instrument Diagram – Unit 277 – Instrument Air – Plant Air and Nitrogen

25179-291-M60-0000-F0201

Piping and Instrument Diagram – Unit 291 – Nitrogen – Plant Air and Instrument Air Distribution

25179-291-M60-0000-F0301

Piping and Instrument Diagram Unit 291 Booster Compressor Auxiliary Train 2

25179-291-M60-0000-F0302

Piping and Instrument Diagram Unit 291 Booster Compressor Auxiliary Train 2

ELECTRONIC DOCUMENTS ARE CONTROLLED. ANY PRINTED COPY WILL BE UNCONTROLLED AND MAY BECOME OUTDATED Bechtel_Instrument Air and Plant Air Unit 267_R4

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