Operating & Control Philosophy.doc

DESIGN, FABRICATION,SUPPLY, INSTALLATION & COMMISSIONING OF A PILOT PLANT FOR DEHYDRATION OF GAS DOCUMENT TITLE: OPERATION AND CONTROL PHILOSOPHY Rev: 0

DOCUMENT NO: OGX-991-H-PCS-DOC-2001

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OPERATIONS AND CONTROL PHILOSOPHY

DESIGN, FABRICATION,SUPPLY, INSTALLATION & COMMISSIONING OF A PILOT PLANT FOR DEHYDRATION OF GAS DOCUMENT TITLE: OPERATION AND CONTROL PHILOSOPHY Rev: 0

Sl.No. 1.0 2.0 3.0 4.0 5.0 6.0 6.1 6.2 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.7

DOCUMENT NO: OGX-991-H-PCS-DOC-2001

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INDEX SHEET Contents Introduction Scope of Work Purpose of the Document Reference Document Abbreviation General Process Description PLC Based Control System Operator Interface Process Control Description Process Gas Filter Separator (FS-001) Molecular Sieve Column (M-001/M-002) Process Gas Cooler (C-001) Silica Gel Column (S-001 – S-006) Knock Out Drum (K-001) Heaters (HE-001/HE-002) Regenerated Gas Cooler (C-002)

Page No 3 3 3 3 4 5 5 6 6 6 6 7 9 10 12 13 14

Annexure A

16

DESIGN, FABRICATION,SUPPLY, INSTALLATION & COMMISSIONING OF A PILOT PLANT FOR DEHYDRATION OF GAS DOCUMENT TITLE: OPERATION AND CONTROL PHILOSOPHY Rev: 0

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Introduction

Oil India Limited (hereinafter referred to as OIL) is a premier National Oil Company engaged in the business of Exploration, Production & Transportation of Crude Oil & Natural Gas. Its operations are largely based in the North-Eastern part of India particularly in Assam and Arunachal Pradesh but extended its activities in different parts of India and abroad. OIL uses natural gas for artificial lifting after compression from 13-15 kg/cm²g to 80-90 kg/cm²g. This gas contains considerable amount of heavier (C5+) hydrocarbons and saturated water vapour. OIL is interested to establish a suitable plant for removal of these heavier fractions of hydrocarbons (C5+) and saturated water vapor through adsorption process. IIT Guwahati is the consultant for the said project and is associated with OIL for the whole project including installation & Commissioning till testing of the complete pilot plant project in cycle.

2.0

Scope of Work

Initially, OIL is setting up a Pilot plant to study the feasibility of the same. The scope of work covered under this contract are Design, Fabrication, Supply, Installation and Commissioning of a Pilot Plant in the field of OIL INDIA LIMITED in Upper Assam region of India. BGR Energy has been awarded this contract for the Pilot plant.

3.0

Purpose of the Document

The purpose of this document is to describe in brief the operating and control philosophy of the Pilot GDU in Upper Assam region of India. This document is considered as a supplement to the project modified P&ID’s.

4.0

Reference Document

Reference is made to the following listed documents while preparing this Operation & Control Philosophy.

DOCUMENT TITLE

DOCUMENT NUMBER

P&ID for Gas Dehydration Unit

OGX-991-H-PCS-PID-1002 SHEET 1 – 3 OF 4

General arrangement drawing for filter separator

OGX-0991-H-MEC-DWG-2301

DESIGN, FABRICATION,SUPPLY, INSTALLATION & COMMISSIONING OF A PILOT PLANT FOR DEHYDRATION OF GAS DOCUMENT TITLE: OPERATION AND CONTROL PHILOSOPHY Rev: 0

DOCUMENT NO: OGX-991-H-PCS-DOC-2001

General arrangement drawing for molecular sieve column General arrangement drawing for silica gel adsorber column General arrangement drawing for process cooler General arrangement drawing for regenerated gas cooler General arrangement drawing for knock out drum

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OGX-0991-H-MEC-DWG-2302 OGX-0991-H-MEC-DWG-2304 OGX-0991-H-MEC-DWG-2310 OGX-0991-H-MEC-DWG-2311 OGX-0991-H-MEC-DWG-2312

Abbreviation DPG FCV FE FIT FS GCS HC HMI KOD LG OIL PG PIT PLC PRV PS PSV PT SCMD SP TE TG TIC TIT TS TT

Differential Pressure Gauge Flow Control Valve Flow Element Flow Indicator Transmitter Filter Separator Gas Collection Stations Hydro Carbon Human Machine Interface Knock Out Drum Level Gauge Oil India Limited Pressure Gauge Pressure Indicator Transmitter Programmable Logic Controllers Pressure Reducing Valve Pressure Switch Pressure Safety Valve Pressure Transmitter Standard Cubic Meter Per Day Sample Point Temperature Element Temperature Gauge Temperature Indicator Controller Temperature Indicator Transmitter Temperature Switch Temperature Transmitter

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DOCUMENT NO: OGX-991-H-PCS-DOC-2001

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General Process Description

Objective of the process is to remove moisture and C5+ Hydrocarbons (HC). Natural gas at 50°C (approx.) and 15 kg/cm2 pressure shall pass through a Coalescence type Filter Separator (FS-001) for removal of any liquid in the flow stream. There are eight adsorption beds in the process (two for water vapour (M-001 & M-002) and six for (S-001 to S-006) HC removal). At a time, four (one for water vapour and three for HC removal) will run in adsorption mode and the other four will run in the desorption mode. The outlet stream of natural gas from the filters will pass successively through adsorption beds for water vapour and HC removal. Once adsorption beds are saturated, they will be switched over to the regeneration mode and the regenerated beds will be switched into the adsorption mode. The dry gas (free of water vapor and heavier HCs) shall be delivered for downstream utilization. A part of the processed dry gas shall be used for high temperature regeneration of the saturated adsorption beds. In addition, if the required flow of hot regenerated gas is large, some raw feed gas may also be mixed with this stream before sending it through the electric heaters. The electric heaters are provided – one for heating regeneration gas to 290°C for Modular Sieve column regeneration and to 160°C for Silica gel columns. The hot gas from the heaters is then sent to the beds for regeneration at low pressure (2-3 kg/cm2g). Since the temperature of this stream laden with high content of moisture and/or heavy HC is high, it is cooled to 35°C and delivered to a nearby oil processing station.

6.1

PLC Based Control System:

The GDU plant will be controlled by PLC based system along with panel HMI. The PLC’s main function will be to control the sequence of Adsorption and Regeneration cycle and protect the system during abnormal conditions and for acquiring various Level, Flow, temperature and pressure inputs. HMI: The HMI shall be fixed on the panel, and which shall be fixed at field. Operators shall monitor the process and alarm management from HMI. PLC: The PLC Control panel along with its associated hardware and power supply units is located in the field. The PLC consists of input/output cards to acquire the I/Os from field. The I/O system supplied is capable of accepting and providing signals, which are:  

4-20mA receives from field transmitters as an analog input. Providing 4-20mA signals to the Field Control Elements as an analog output.

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Digital-Potential free contact inputs from field switches as a digital input. Providing controlled outputs to the Solenoid valves as a digital output.

System configuration of PLC system shall be as per enclosed Annexure-A. Third Party Device to Be Integrated 2nos. of Electrical heater control panels controllers in safe area through RS485 MODBUS communication loop.

6.2

Operator Interface:

The Operator interface with the plant shall be through HMI which shall enable full surveillance and supervision of the process. HMI shall have operation and control button like Start/Stop PB’s, Local/Remote Selection, Auto/Manual selector’s switches wherever applicable. All Control and alarm functions shall be displayed in HMI’s screen.

7.0

Process Control Description

7.1

Process Gas:

The process gas is a slip stream from an existing pipeline network at one of the GCS of OIL. This stream is passed through a filter separator (FS-001) to remove entrained liquid before passing into Molecular sieve column (M-001/M-002) and Knock out drum (K-001). The gas is delivered at the flow rate of 2000 SCMD @ 15 kg/cm2g & 50oC.

7.2

Filter Separator (FS-001):

The entrained liquid (5 microns and above) in the process gas is removed with 99% efficiency, by coalescing into droplets, to settle out of the gas rapidly into the drain. This operation will reduce the load in the molecular sieve column (M-001/M-002). The pressure drop across the filter separator is 0.1 kg/cm2. The operating process variables are ensured persistently through the instruments listed in the below table 1.1.

DESIGN, FABRICATION,SUPPLY, INSTALLATION & COMMISSIONING OF A PILOT PLANT FOR DEHYDRATION OF GAS DOCUMENT TITLE: OPERATION AND CONTROL PHILOSOPHY Rev: 0

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TABLE 1.1 S.NO 1.

TAG PG 101

DESCRIPTION Pressure Gauge

RANGE 0 – 24 kg/cm2g

2.

DPG 101

Differential Pressure Gauge

0 – 1 kg/cm2

3. 4.

TG 101 LG 101

Temperature Gauge Level Gauge

0 – 100 oC -

SET POINT -

2

5.

PT 101

Pressure Transmitter

0 – 24 kg/cm g

6.

PSV 101

Pressure Safety Valve

-

H – 18 kg/cm2g L – 13.1 kg/cm2g 20 kg/cm2g

If the pressure lowers, due to filter clogging or any other unpredictable scenario, the filter elements are protected by prompt closing of ON-OFF valve (XV-101) in response to the low pressure alarm from the pressure transmitter (PT-101). PSV is provided to protect the vessel from exceeding the design pressure of 20 kg/cm2g.

7.3

Molecular Sieve Column (M-001/M-002):

The main two process involved are as below,  Adsorption – 12 hours (720 minutes)  Regeneration (desorption) – 12 hours (720 minutes) During adsorption mode the molecular sieve column (M-001) receives the gas of 1000 MD in a controlled volume at 13.6 kg/cm2g and 50 oC through an Orifice Flow meter (FE-101), Flow Transmitter (FIT-101) & a Flow control valve (FCV-101). Once the gas enters from the bottom of the vessel, it passes through the molecular sieves of type Adsorbmax 100 (4A), where the moisture content is removed. Flow controller FIC-101 controls to 1000 SCMD. While above adsorption is on in molecular sieve column (M-001), the molecular sieve column (M002) will be under regeneration, where the molecular sieve column receives the heated gas of 164 SCMD in a controlled volume at 2.5 kg/cm2g and 290 oC. Once the gas enters the column, passes through the molecular sieves, where the desorption of moisture taken place due to the high temperature of regeneration gas. This stream of rich, high temperature and high moisture content gas is sent to inlet common header of regenerated gas cooler (C-002). The regeneration process cycle is a cluster of the following consecutive sub-processes. 1. Depressurization 2. Heating 3. Cooling

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4. Pressurization For the regeneration of column M-002, the depressurization valve (XV 109) opens & allows the pressurized gas in the column (M-002) to safe vent header, in order to favor the consequent process parametric condition (2.5 kg/cm2g) of depressurization. This process extends up to 5 minute. After 5 minute of depressurization, the valve (XV 109) is closed and the heater (HE-001) switched ON, then low pressure hot gas is passed to the column (M-002). Here the low pressure hot gas will carry moisture from adsorbents (molecular sieve) and leaves to the LP unit through a regenerated gas cooler (C-002). This process is called heating and extends up to 430 minutes. After heating process, the heater (HE-001) will be switch off and runs for 270 minutes. Here the adsorbents will cool down to 40 oC. This process is called cooling. After cooling, the column (M-002) will be pressured up to operating pressure to favor the adsorption condition. This process extends up to 15 minutes and is called pressurization. After 720 minutes, the bed changeover will take place automatically, the column (M-002) will be in adsorption mode and the column (M-001) will go in regeneration mode. The operating process variables are ensured persistently through the list of instruments listed in the below table 1.2. TABLE 1.2 S.NO

TAG

DESCRIPTION

RANGE

1.

FIT 101

Flow Indicating Transmitter

-

2.

FCV 101

Flow control valve

-

3.

PG 102/103

Pressure Gauge

0 – 24 kg/cm2g

4.

PS 101/102

Pressure Switch

0 – 2.5 kg/cm2g

5.

PT 102/103

Pressure Transmitter

0 – 24 kg/cm2g

6.

TT 102/103

Temperature Transmitter

0 – 470 oC

SET POINT H – 43.2 kg/hr L – 28.8 kg/hr H – 43.2 kg/hr L – 28.8 kg/hr -

7.

TS 101/102

Temperature Switch

-

L – 2.1 kg/cm2g H – 16.3 kg/cm2g L – 2.1 kg/cm2g H – 295 oC L – 45 oC H – 295 oC

8.

PSV 102/103

Pressure Safety Valve

-

20 kg/cm2g

The sequence of adsorption and regeneration operation is as of below table 1.3.

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TABLE 1.3 OPERATION SEQUENCE TABLE M-001

Drying

Drying

Drying

Drying

Depressurization

Heating

Cooling

Pressurization

M-002

Depressurization

Heating

Cooling

Pressurization

Drying

Drying

Drying

Drying

HE-001

OFF

ON

OFF

OFF

OFF

ON

OFF

OFF

XV 102

ON

ON

ON

ON

OFF

OFF

OFF

OFF

XV 104

ON

ON

ON

ON

OFF

OFF

OFF

OFF

XV 105

OFF

OFF

OFF

OFF

ON

ON

ON

ON

XV 106

OFF

ON

ON

OFF

OFF

OFF

OFF

OFF

XV 107

OFF

OFF

OFF

ON

OFF

OFF

OFF

ON

XV 108

OFF

OFF

OFF

OFF

ON

OFF

OFF

SOFF

XV 109

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

XV 110

OFF

OFF

OFF

OFF

OFF

ON

ON

OFF

XV 111

OFF

ON

ON

OFF

OFF

OFF

OFF

OFF

XV 112

OFF

OFF

OFF

OFF

ON

ON

ON

ON

XV 113

OFF

OFF

OFF

OFF

OFF

ON

ON

OFF

XV 126*

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

0

5

435

705

720

725

1155

1425

1440

MINUTES * to be used as heater bypass when required due to maintenance.

In case of Flow control valve (FCV-101) failure or bed clog during adsorption, the prompt action of ON-OFF valve (XV-101) protects the column based on the high/low flow alarm from the flow indicating transmitter (FIT-101) or based on high/low alarm from the pressure transmitter (PT 102). The instruments like pressure and temperature switch provided to protect the column from extreme parametric conditions by prompt action of ON-OFF valve (XV-103) during regeneration. In addition, PSV is provided to protect the column from exceeding the design pressure of 20 kg/cm2g.

7.4

Process Gas Cooler (C-001) - Natural Draft (Air):

A natural draft (air) process gas cooler (C-001) is provided to cool the dehydrated gas. It is cooled to a temperature of 35 oC in order to favor the adsorption process in silica gel column (i.e.) f or the better C5+ HC adsorption. The operating process variables are ensured persistently through the list of instruments listed in the below table 1.4.

TABLE 1.4

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S.NO 1.

7.5

TAG PG 104

DESCRIPTION

PAGE 10 OF 14

RANGE

Pressure Gauge

SET POINT 2

-

2

-

0 – 24 kg/cm g

2.

PG 105

Pressure Gauge

0 – 24 kg/cm g

3.

TG 104

Temperature Gauge

0 – 50 oC

-

4.

TS 103

Temperature Switch

-

H – 55 oC

Silica Gel Column (S-001 – S-006):

As same as molecular and regeneration mode.

sieve column, silica

gel column also undergoes adsorption

 Adsorption – 8 hours (480 minutes)  Regeneration (desorption) – 8 hours (480 minutes) In adsorption process, the outlet stream of the process gas cooler (C-001) at 13.6 kg/cm2g and 35 o C passes through the silica gel bed of type spherical beads 2.5 mm for the removal of C5+ HC. While above process is taking place at silica gel column (S-001/002/003), the silica gel column (S004/005/006) will be under regeneration, where the silica gel column receives the heated gas of 1780 SCMD in a controlled volume at 2.5 kg/cm 2g and 160 oC for the removal of deposited C5+ HC. The regeneration process is a cluster of the following consecutive sub-processes. 1. Depressurization 2. Heating 3. Cooling 4. Pressurization The depressurization valve (XV 124) opens & allows the compressed air in the column (S004/005/006) to safe vent header, in order to favor the consequent process parametric condition (2.5 kg/cm2g) of depressurization. This process extends up to 10 minute. After 10 minute of depressurization, the valve (XV 124) is closed and the heater (HE-002) switched ON, then low pressure hot gas is passed to the column (S-004/005/006). Here the low pressure hot gas will carry the removed C5+ Hydrocarbon compound during adsorption from adsorbents (silica gel) and leaves to the LP unit through a regenerated gas cooler (C-002). This process is called heating and extends up to 293 minutes. After heating process, the heater (HE-002) will be switch off and runs up to 148 minutes. Here the adsorbents will cool down to 40 oC. This process is called cooling.

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After cooling, the column (S-004/005/006) will be pressured up to operating pressure to favor the adsorption condition. This process extends up to 29 minutes and is called pressurization. After 480 minutes, the bed changeover will take place automatically, the column (M-002) will be in adsorption mode and the column (M-001) will go in regeneration mode. For a study purpose, activated carbon is used as a replacement for the silica gel adsorbent. The main purpose of this study is to minimize the regeneration requirement for silica gel bed, as less quantity of activated carbon is required to remove heavier hydrocarbons compared to silica gel. The adsorption and regeneration cycle time is same as of the silica gel adsorbent. The only difference is in the regeneration temperature, for activated carbon it is 130 oC, the rest of the parameters are the same. The operating process variables are ensured persistently through the list of instruments listed in the below table 1.5. TABLE 1.5 S.NO 1. 2.

TAG PG 106 - 111 PS 103 - 108

DESCRIPTION Pressure Gauge Pressure Switch

RANGE 0 – 24 kg/cm2g 0 – 2.5 kg/cm2g

3.

PT 106 - 111

Pressure Transmitter

0 – 24 kg/cm2g

4.

TT 105 - 134

Temperature Transmitter

0 – 260 oC

5. 6. 7.

TS 104 - 109 PRV 102 PSV 104 - 109

Temperature Switch Pressure Reducing Valve Pressure Safety Valve

0 – 260 oC 0 – 24 kg/cm2g -

SET POINT L – 2.1 kg/cm2g H – 16.1 kg/cm2g L – 2.1 kg/cm2g H – 165 oC L – 30 oC H – 165 oC 2.2 kg/cm2g 20 kg/cm2g

The status of various shut off valves during the sequence of adsorption and regeneration operation is as of below table 1.6.

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TABLE 1.6 OPERATION SEQUENCE TABLE S001/002/003 S004/005/006

Drying

Drying

Drying

Drying

Depressurization

Heating

Cooling

Pressurization

Depressurization

Heating

Cooling

Pressurization

Drying

Drying

Drying

Drying

HE-002

OFF

ON

OFF

OFF

OFF

ON

OFF

OFF

XV 114

ON

ON

ON

ON

OFF

OFF

OFF

OFF

XV 115

OFF

OFF

OFF

OFF

ON

ON

ON

ON

XV 116

OFF

OFF

OFF

OFF

OFF

ON

ON

OFF

XV 117

OFF

OFF

OFF

OFF

ON

OFF

OFF

OFF

XV 118

OFF

OFF

OFF

ON

OFF

OFF

OFF

ON

XV 119

OFF

OFF

OFF

OFF

OFF

ON

ON

OFF

XV 120

ON

ON

ON

ON

OFF

OFF

OFF

OFF

XV 121

OFF

ON

ON

OFF

OFF

OFF

OFF

OFF

XV 122

OFF

ON

ON

OFF

OFF

OFF

OFF

OFF

XV 123

OFF

OFF

OFF

OFF

ON

ON

ON

ON

XV 124

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

XV 125 XV 127* 0

ON

ON

ON

ON

ON

ON

ON

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

10

303

451

480

490

783

931

960

MINUTES * to be used as heater bypass when required due to maintenance.

In case of Process upsets, the action of ON-OFF valve (XV-101) protects the complete GDU based on the high/low pressure alarm from the pressure transmitter (PT 106/107/108). The dedicated PSV of each vessel, protects adsorbers from exceeding the design pressure of 20 kg/cm2. The lean gas (after removal of moisture content and C5+ HC’s) is sent to nearby oil processing system.

7.6

Knock Out Drum (K-001):

The objective of KOD is to entrain the liquid content in mixed gas (i.e.) part of the incoming gas of 1000 SCMD @ 14.50 kg/cm2 & 50 oC and part of the lean gas from silica gel column 944 SCMD @ 13.19 kg/cm2 & 35 oC. Since a low pressure conditions is required for the regeneration process, PRV is provided at each stream of the gas, reduced to 3.05 kg/cm2.

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The operating process variables are ensured persistently through the list of instruments listed in the below table 1.7. TABLE 1.7 S.NO

TAG

DESCRIPTION

RANGE

SET POINT H – 40.8 kg/hr L – 27.2 kg/hr H – 40.8 kg/hr L – 27.2 kg/hr

1.

FIT 104

Flow Indicating Transmitter

-

2.

FCV 104

Flow Control Valve

-

3.

PRV 101

Pressure Reducing Valve

0 – 24 kg/cm2g 2

3.05 kg/cm2g

4.

PRV 103

Pressure Reducing Valve

0 – 24 kg/cm g

5.

PT 112

Pressure Transmitter

0 – 24 kg/cm2g

6.

PG 114

Pressure Gauge

0 – 24 kg/cm2g

3.05 kg/cm2g H – 3.66 kg/cm2g L – 2.65 kg/cm2g -

7.

LG 102

Level Gauge

-

-

8.

PSV 110

Pressure Safety Valve

-

20 kg/cm2g

In case of demister pad clog or any other unpredictable scenario, the vessel is protected by prompt closing of ON-OFF valve (XV-125) & (XV-103). In addition, PSV is provided to protect the vessel from exceeding the design pressure of 20 kg/cm2.

7.7

Heaters (HE-001/HE-002):

The objective of the heaters is to heat the process gas for regeneration process. Two electric heaters, one for molecular sieve columns and the other for silica gel columns are provided. Heater (HE-001) receives the gas of 164 SCMD in a controlled volume at 2.6 kg/cm 2g and 36 oC through an Orifice meter (FE-102) & a Flow control valve (FCV-102). Once the gas enters the heater, it is heated to 290 oC, a suitable temperature for the removal of deposited moisture content from the molecular sieve column. Heater (HE-002) receives the gas of 1780 SCMD in a controlled volume at 2.6 kg/cm 2g and 36 oC through an Orifice meter (FE-103) & a Flow control valve (FCV-103). Once the gas enters the heater, it is heated to 160 oC, a suitable temperature for the removal of deposited C5+ HC’s content from the silica gel columns. The process gas is heated with respect to the closure of ON-OFF valves such as XV-126 & XV-127. It may be used for passing heaters HE-001 & HE-002 respectively in case under maintenance. The operating process variables are ensured persistently through the list of instruments listed in the below table 1.8.

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TABLE 1.8 S.NO

TAG

DESCRIPTION

RANGE

SET POINT H – 40.8 kg/hr L – 27.2 kg/hr H – 40.8 kg/hr L – 27.2 kg/hr H – 40.8 kg/hr L – 27.2 kg/hr H – 40.8 kg/hr L – 27.2 kg/hr

1.

FIT 102

Flow Indicating Transmitter

-

2.

FIT 103

Flow Indicating Transmitter

-

3.

FCV 102

Flow Control Valve

-

4.

FCV 103

Flow Control Valve

-

5.

PG 112

Pressure Gauge

0 – 24 kg/cm2g 2

3.05 kg/cm2g 3.05 kg/cm2g HH - 300 oC H - 295 oC L - 285 oC LL - 280 oC HH - 300 oC H - 295 oC L - 285 oC LL - 280 oC HH - 300 oC H - 295 oC L - 285 oC LL - 280 oC HH - 170 oC H - 165 oC L - 155 oC LL - 150 oC HH - 170 oC H - 165 oC L - 155 oC LL - 150 oC HH - 170 oC H - 165 oC L - 155 oC LL - 150 oC

6.

PG 113

Pressure Gauge

0 – 24 kg/cm g

7.

TT 141

Temperature Transmitter

0 – 470 oC

8.

TT 142

Temperature Transmitter

0 – 470 oC

9.

TT 137

Temperature Transmitter

0 – 470 oC

10.

TT 143

Temperature Transmitter

0 – 260 oC

11.

TT 144

Temperature Transmitter

0 – 260 oC

12.

TT 138

Temperature Transmitter

0 – 260 oC

13.

TG 102

Temperature Gauge

0 – 400 oC

-

14.

TG 103

Temperature Gauge

0 – 275 oC

-

15.

PSV 111/112

Pressure Safety Valve

-

20 kg/cm2g

A dedicated local heater panel is provided to control (ON/OFF) the respective heater through PLC. In addition, PSV is provided to protect the heaters from exceeding the design pressure of 20 kg/cm2.

7.8

Regenerated Gas Cooler (C-001) - Forced Draft (Air):

The outlet product of the regenerated molecular sieve column of 164 SCMD @ 2.5 kg/cm 2g and 290 oC, the silica gel column of 1780 SCMD @ 2.5 kg/cm2g and 160 oC gets collected in common header of the regenerated gas cooler inlet. Since the product is at high temperature, it has to be

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DOCUMENT NO: OGX-991-H-PCS-DOC-2001

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cooled before letting it out to the LPS system. The operating process variables are ensured persistently through the list of instruments listed in the below table 1.9. TABLE 1.9 S.NO 1. 2.

TAG PG 115 PG 116

DESCRIPTION Pressure Gauge Pressure Gauge

RANGE 0 – 24 kg/cm2g 0 – 24 kg/cm2g

3.

PT 104

Pressure Transmitter

0 – 24 kg/cm2g

4.

PT 105

Pressure Transmitter

0 – 24 kg/cm2g

5. 6.

TG 105 TG 106

Temperature Gauge Temperature Gauge

0 – 250 oC 0 – 50 oC

SET POINT H – 2.9 kg/cm2g L – 1.9 kg/cm2g H – 2.5 kg/cm2g L – 1.6 kg/cm2g -

The equipment is protected from extreme parametric conditions by pressure transmitter (PT 104 & PT 105) by shut down of XV 103. This cooler will be controlled through PLC in a manual ON-OFF mode i.e., when to switch on & switch off. OIL will take care if there is any change in downstream temperature of this cooler.

DESIGN, FABRICATION,SUPPLY, INSTALLATION & COMMISSIONING OF A PILOT PLANT FOR DEHYDRATION OF GAS DOCUMENT TITLE: OPERATION AND CONTROL PHILOSOPHY Rev: 0

DOCUMENT NO: OGX-991-H-PCS-DOC-2001

ANNEXURE A

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