projrep

OPERATION PHILOSOPHY OF GAS HOLDER IN
STEEL PLANT
PROJECT REPORT SUBMITTED
FOR THE COMPLETION OF
SUMMER INTERNSHIP
AT
TATA STEEL
JAMSHEDPUR
Under the Guidance of
Mr. Shyam Manohar Pandey
Submitted By:-
 Name : ABHISHEK MOHATA
 College : Budge Budge Institute of Technology, Kolkata
 VT NO. : VT20150505
 RFID NO. : VT0615153162
 GP NO. : TST/978856/0715

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DECLARATION
I hereby declare that the project entitled "Operation Philosophy of Gas Holder in Steel
Plant”, submitted in partial fulfilment of B.Tech Degree, was carried out with sincere
intention of benefiting the organization. The project duration was from 23rdJune - 17th
August, 2015.
To the best of my knowledge it is an original piece of work done by me and it has neither been
submitted to any other organization nor published at anywhere before.
The findings and conclusions of this report are based on my personal study and experience,
during the tenure of my summer internship.
Name : Abhishek Mohata
Signature :
Date :

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CERTIFICATE OF RECOMMENDATION
This is to certify that the project entitled "Operation Philosophy of Gas Holder in Steel Plant"
is a bona-fide work carried out by Abhishek Mohata under my supervision and guidance,
and may be accepted in partial fulfilment of the requirements for the award of Graduate
degree of Bachelor of Technology in Mechanical Engineering, Budge Budge Institute of
Technology, Kolkata.
……………………………………….
Mr. Shyam Manohar Pandey
(Project Guide)
Manager
Central Project Engineering Division
TATA STEEL
Countersigned by
……………………………………….
Mr. Nripendra Tripathy
Senior Manager
Central Project Engineering Division
TATA STEEL

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Acknowledgements
I am fortunate enough to come in contact with some great Engineers during
my Summer Internship at TATA STEEL, Jamshedpur. They touched me with
their vast knowledge, warm enthusiasm and friendly criticism.
I consider myself lucky to have the guidance of Mr. Shyam Manohar
Pandey, Manager, Central Project Engineering Division, Tata Steel,
Jamshedpur, who took time from his busy schedule to guide me through my
internship constantly. I shall be ever grateful to him and owe my sincere
debt to my guide.
I take the opportunity to express my gratitude to Mr. Nripendra Triptahy,
Senior Manager, Central Project Engineering Division, Tata Steel,
Jamshedpur for his continuous support he gave me by facilitating me with
all requirements and taking care. I wouldn’t have been able to get through
my internship without his encouragement and affection.
I am thankful to Mr. Ravi Kant, Manager, Central Project Engineering
Division, Tata Steel, Jamshedpur
Also to Mr. J.P. Singh, Manager, Central Project Engineering Division, Tata
Steel, Jamshedpur for their encouragement and co-operation.
I thankfully acknowledge the whole hearted support rendered by office
staffs, on-site staffs of JUSCO Team and the on-site workers of Tata Steel for
completing my internship.

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I take the opportunity to express my heartiest reverence to my parents who
have worked very hard throughout their life to make me what I am today.
I am thankful to all who have assisted me directly or indirectly to
accomplish this work.
At last but not the least, I am very grateful to the Almighty for keeping me
healthy throughout the internship period.
Dated:
Budge Budge Institute of Technology
Kolkata
Abhishek Mohata

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ABSTRACT
The cost of fuel is increasing rapidly these days and, the quantity is limited. In
integrated steel plant many gases are generated from the Blast Furnace, Coke
Oven and LD System. These gases contain high amount of carbon monoxide
(CO) which can be used as a fuel for different purpose. A Gas Holder helps in
the storing this useful CO gas which is otherwise flared into the atmosphere.
Flaring of useful CO gas not only affects the company’s economy but also
affects the environment. So, in order to stop such loss and environmental
degradation, Gas Holder becomes an important part of the integrated steel
plant. Efforts have been made to study the minute details about a Gas Holder
which is very essential for its safe operation.

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CONTENTS
PAGE NO.
ACKNOWLEDGEMENTS ....................................................................................................................4
ABSTRACT........................................................................................................................................................6
CONTENTS .......................................................................................................................................................7
CHAPTER-1: COMPANY PROFILE
1.1 THE COMPANY BACKGROUND.............................................................................................................10
1.2 GROWTH AND GLOBALISATION ..........................................................................................................12
CHAPTER-2: INTRODUCTION
2.1 INTRODUCTION..................................................................................................................................13
2.2 TYPES OF GAS HOLDERS.....................................................................................................................14
2.3 MAIN PARTS OF A GAS HOLDER.........................................................................................................15
2.3.1 FOUNDATION............................................................................................................................................15
2.3.2 MAIN TANK..............................................................................................................................................15
2.3.3 PISTON....................................................................................................................................................18
2.3.4 SEALING...................................................................................................................................................21
CHAPTER-3: WIGGINS TYPE GAS HOLDER
3.1 INTRODUCTION..................................................................................................................................22
3.2 STAGE WISE OPERATION....................................................................................................................23
CHAPTER-4: M.A.N TYPE GAS HOLDER
4.1 INTRODUCTION..................................................................................................................................35
4.2 OBJECTIVE OF THE PROJECT ...............................................................................................................36
4.3 OPERATION PRINCIPLE.......................................................................................................................37
4.4 MAIN PARAMETERS...........................................................................................................................38
CHAPTER-5: ERECTION & INSTALLATION
5.1 FOUNDATION CHECK AND ACCEPTANCE............................................................................................39
5.2 ERECTION AND INSTALLATION WORK................................................................................................40

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5.2.1 PHASE I..................................................................................................................................................40
5.2.2 PHASE II.................................................................................................................................................46
5.2.3 PHASE III................................................................................................................................................50
5.3 LIFTING PROPOSAL.............................................................................................................................51
5.3.1 BOTTOM PLATE LAYING AND BASE COLUMN LIFTING ..........................................................................................51
5.3.2 TRUSS LIFTING ..........................................................................................................................................51
5.3.3 ROOF TRUSS AND ROOF PLATE LIFTING..........................................................................................................51
5.3.4 COLUMN, SIDE PLATE, ELEVATOR SHAFT LIFTING...............................................................................................52
5.4 WELDING SPECIFICATION...................................................................................................................52
5.4.1 BASIC REQUIREMENT .................................................................................................................................52
5.4.2 WELDING MATERIAL AND MANAGEMENT ......................................................................................................52
5.4.3 PREPARATION WORK ..................................................................................................................................53
5.4.4 WELDING.................................................................................................................................................53
5.4.5 WELDING QUALITY REQUIREMENT................................................................................................................56
5.5 ERECTION QUALITY CONTROL............................................................................................................57
5.5.1 FOUNDATION RECHECK...............................................................................................................................57
5.5.2 SIDE PLATE ASSEMBLY CONTROL ..................................................................................................................58
5.5.3 BOTTOM PLATE QUALITY CONTROL...............................................................................................................58
5.5.4 BASE COLUMN QUALITY CONTROL................................................................................................................58
5.5.5 2ND
COLUMN AND OTHERS QUALITY CONTROL..................................................................................................59
5.5.6 ROOF FRAME QUALITY CONTROL..................................................................................................................59
5.5.7 PISTON QUALITY CONTROL..........................................................................................................................59
5.5.8 SEALING DEVICE QUALITY CONTROL..............................................................................................................60
5.5.9 GUIDE WHEEL QUALITY CONTROL ................................................................................................................60
5.5.10 PISTON RUNNING TEST ..............................................................................................................................60
5.5.11 GAS HOLDER TIGHTNESS TEST.....................................................................................................................61
5.5.12 ERECTION SEQUENCE CHART.......................................................................................................................62
CHAPTER-6: PLANT OPERATION & MAINTENANCE
6.1 CONFIGURATION AND FUNCTION......................................................................................................63
6.1.1 50000M3
OIL SEALED GAS HOLDER.............................................................................................................63
6.1.2 ELECTRIC SYSTEM ......................................................................................................................................70
6.1.3 CONTROL SYSTEM......................................................................................................................................71
6.1.4 VALVES, WATER SEAL AND PIPELINE...............................................................................................................74
6.1.5 WATER SUPPLY AND FIRE FIGHTING WATER.....................................................................................................76
6.1.6 AIR CONDITION AND VENTILATION SYSTEM......................................................................................................77
6.1.7 OIL SEAL SYSTEM .......................................................................................................................................77
CHAPTER-7: OPERATION PHILOSOPHY
7.1 PREPARATION WORK BEFORE COMMISSIONING................................................................................85
7.2 NITROGEN GAS EXCHANGE AIR...........................................................................................................86
7.3 CO GAS EXCHANGE NITROGEN GAS ....................................................................................................86

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7.4 NORMAL WORKING CONDITION.........................................................................................................87
7.5 MAINTENANCE AND REPAIR ON PLAN (NITROGEN EXCHANGE CO) ....................................................88
7.6 EMERGENCY CONDITION ....................................................................................................................88
7.7 POSITION AND RESPONSIBILITY..........................................................................................................90
7.8 PAY SPECIAL ATTENTION.....................................................................................................................91
CHAPTER-8: SAFETY RULES
CHAPTER-9 CONCLUSION & BIBLIOGRAPHY
9.1 CONCLUSION ......................................................................................................................................94
9.2 BIBLIOGRAPHY....................................................................................................................................95

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CHAPTER
1
COMPANY PROFILE
1.1 The Company Background
TATA STEEL LTD, formerly known as TISCO (Tata Iron and Steel Company Limited), is
the world’s sixth largest steel company, with an annual crude steel capacity of 30
Million tonnes Per Annum (MTPA). It is the second largest private sector steel
company in India in terms of domestic production. Ranked 315th
on
Fortune Global 500, it is based in Jamshedpur, Jharkhand, India.
It is part of Tata Group of
company in private sector.
The world of Tata Steel is
one without boundaries –
growing, changing and
challenging every day. A
world that embraces
different skills, continuous
innovation, financial
investment, responsible
use of natural resources and above all there is the enduring commitment of giving
back to society that helps make the vision of sustainable growth a reality.
Operations in 26 countries, Commercial presence in over 50 Countries and 80,000
employees across five continents. What sets the Tata Steel Group apart is not just
the extent or magnitude of its operations – it is the excellence of its people,
innovative approach, and overall conduct. Established in 1907 as Asia’s first
integrated private sector steel company, Tata Steel Group is among the top-ten
global steel companies with an annual crude steel capacity of nearly 30 million
tonnes per annum. It is now the world’s second-most geographically-diversified
steel producer. The Group recorded a turnover of Rs. 139,504 crores in FY 15.
Figure 1.1 : Tata Steel at Night

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Tata Steel is backed by 100 glorious years of experience in steel making. Established
in 1907, it is the first integrated steel plant in Asia and is now the world’s second
most geographically diversified steel producer and a Fortune 500 Company.Tata
Steel has a balanced global presence in over 50 developed European and fast
growing Asian markets, with manufacturing units in 26 countries. It was the vision of
the founder; Jamshedji Nusserwanji Tata, that on 27th
February, 1908 the first stake
was driven into the soil of sakchi. His vision helped Tata Steel overcome several
periods of adversity and strive to improve against all odds.
Tata Steel’s Jamshedpur (India) Works has a crude steel production capacity of 6.8
MTPA which is slated to increase to 10 MTPA by 2010. The Company also has
proposed three Greenfield steel projects in the states of Jharkhand, Orissa and
Chhattisgarh in India with additional capacity of 23 MTPA and a Greenfield project in
Vietnam. Through investments in Corus, Millennium Steel (renamed Tata Steel
Thailand) and Nat Steel Holdings, Singapore, Tata Steel has created a manufacturing
and marketing network in Europe, South East Asia and the Pacific Rim Countries.
Corus which manufactured over 20 MTPA of steel in 2008 has operations in the UK,
the Netherlands, Germany, France, Norway and Belgium. Tata Steel Thailand is the
largest producer of long steel products in Thailand, with a manufacturing capacity of
1.7 MTPA. Tata Steel has proposed a 0.5 MTPA mini blast furnace project in
Thailand. Nat Steel Holdings produces about 2 MTPA of steel products across its
regional operations in seven countries.
Tata Steel has lined up a series of Greenfield projects in India and outside which
includes:
A. 6 million tonnes plant in Orissa (India).
B. 12 million tonnes plant in Jharkhand (India).
C. 5 million tonnes plant in Chhattisgarh (India).
D. 3 million tonnes plant in Iran.
E. 6.8 million tonnes capacity expansion at Jamshedpur (India).
F. 4.5 million tonnes plant in Vietnam (feasibility study underway).
Tata Steel, through its joint venture with Tata Blue Scope Steel Limited, has also
entered the steel building and construction applications market.
The iron ore mines and collieries in India give the Company a distinct advantage in
raw material sourcing. Tata Steel is also striving towards raw materials security
through joint ventures in Thailand, Australia, Mozambique, Ivory Coast (West Africa)
and Oman. Tata Steel has signed an agreement with Steel Authority of India Limited

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to establish a 50:50 joint venture company for coal mining in India. Also, Tata Steel
has bought 19.9% stake in New Millennium Capital Corporation, Canada for Iron Ore
Mining.
1.2 GROWTH AND GLOBALISATION
Indian Operations:
Tata Steel founded India’s first industrial city, now Jamshedpur, where it established
India’s first integrated steel plant in 1907. The Jamshedpur Works currently comprises
of a 9.7 MTPA crude steel production facility and a variety of finishing mills. Mines
and collieries in India give the company a distinct advantage in raw material sourcing.
Looking further into the future, the company plans to continue to increase its capacity
significantly through both brownfield and greenfield developments.
European Operations:
Tata Steel Europe (erstwhile Corus) has a crude steel production capacity of 18 MTPA.
Tata Steel Europe has manufacturing operations in Mainland Europe, plants in UK,
Netherlands, Germany, France and Belgium, and is backed by a sophisticated global
network of sales offices and service centres.
South East Asian Operations:
Tata Steel started its operations in SEA in 2004 with investments in NatSteel Holdings
and Millennium Steel (now Tata Steel Thailand). With over 40 years of steel making
experience, NatSteel is one of the most prominent steel producers in the Asia Pacific
region. It caters to the growing construction industry through its manufacturing
presence in Singapore, Thailand, China, Malaysia, Vietnam and Australia.

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CHAPTER
2
INTRODUCTION
2.1 Introduction
For iron and steel industries, it is very important to reduce energy costs due to their
tremendous consumption of it. For this reason, they make every effort to recycle various
materials generated from many plants.
These efforts are also significant from the
viewpoint of environmental protection as
well as cost saving. In particular, by-
product gases generated from iron-
making, coke-burning and steel-making
process, called as BFG (Blaster Furnace
Gas), COG (Coke Oven Gas), and LDG (Linz-
Donawitz Gas), respectively, are worthy of
being used as a fuel since they include
considerable amount of CO and H2.
Therefore, these gases are now being
supplied to many plants via gasholders to
be used as a fuel instead of expensive oil
and LNG. The gasholders work as buffers
that store the gases temporarily until the
gas users need them as an energy source.
A gas holder (commonly known as a
gasometer, sometimes also gas bell is a large container in which natural gas or town gas is
stored near atmospheric pressure at ambient temperatures. The volume of the container
follows the quantity of stored gas, with pressure coming from the weight of a movable cap.
Gasholders tend to be used nowadays for balancing purposes (making sure gas pipes can
be operated within a safe range of pressures) rather than for actually storing gas for later
use.
Figure 2.1 : A Blast Furnace Gas Holder

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2.2 Types of Gas Holders
There are two basic types of gasholder:
1. Rigid Waterless: Rigid waterless gas holders were a very early design which showed
no sign of expansion or contraction. There are modern versions of the waterless gas
holder.
e.g. "oil-sealed", "grease-sealed" and "dry seal" (membrane) types.
2. Telescoping: Telescoping holders fall into two subcategories:
 The earlier of the telescoping variety were column guided variations and
were built in Victorian times. To guide the telescoping walls, or "lifts", they
have an external fixed frame, visible at a fixed height at all times.
 Spiral guided gasholders were built in the UK up until 1983. These have no
frame and each lift is guided by the one below, rotating as it goes up as
dictated by helical runners.
Both telescoping types use the manometric property of water to provide a seal. The
whole tank floats in a circular or annular water reservoir, held up by the roughly
constant pressure of a varying volume of gas, the pressure determined by the weight
of the structure, and the water providing the seal for the gas within the moving
walls. Besides storing the gas, the tank's design serves to establish the pressure of
the gas system. With telescoping (multiple lift) tanks, the innermost tank has a 1ft
wide by 2ft high lip around the outside of the bottom edge, called a cup, which picks
up water as it rises above the reservoir water level. This immediately engages a
downward lip on the inner rim of the next outer lift, called a grip, and as this grip
sinks into the cup, it preserves the water seal as the inner tank continues to rise until
the grip grounds on the cup, whereupon further injection of gas will start to raise
that lift as well. Holders were built with as many as four lifts.

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2.3 Main Parts of a Gas Holder
Figure 2.2 : Main Parts of a Gas Holder
2.3.1 Foundation
A concrete and hardcore base designed to withstand the weight of the steel gasholder
structure constructed upon it and to withstand dynamic climatic conditions acting upon the
gasholder etc.
2.3.2 Main Tank
The main tank is designed to accommodate the design requirements laid down by the
customer and climatic conditions. The main sub-elements of the tank are:
 Tank bottom: The tank bottom forms a gas tight seal against the foundation and is
"coned up" to facilitate drainage to the periphery. The bottom is covered with steel
plates. The outer annular plates are butt welded against backing strips, whilst the infill
plates are lap welded on the top side only. Welded to the bottom infill plates is the:
 Piston support structure: When the piston is depressurised it rests on a steel
framework which is welded to the bottom plates.
 Tank shell: The shell of the tank is designed to accommodate the imposed loads
and the general data supplied by the client. The shell is of butt-welded design and

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is gas tight for approximately 40% of its lower vertical height (known as the gas
space) at which point the seal angle is located. The remaining upper 60% (known
as the air space) of the shell has in it various apertures for access and ventilation.
Attached to the shell are various accessories:
1. External Staircase tower and Elevator: For external access to the roof of
the gasholder and also incorporates access to the inside of the gasholder
via the shell access doors. A locked safety gate is usually located at the
base of the staircase to prevent any unauthorised access to the gasholder.
2. Internal Elevator: For internal access to the gas holder.
3. Shell access doors: Doors located at pertinent points allowing access
into the gasholder from the external staircase tower.
4. Shell vents: Allow air to be displaced from the inside of the gasholder as
the piston rises.
5. Inlet nozzle: The connection nozzle allowing the stored gas to enter the
gasholder from the supply gas main.
6. Outlet nozzle: For the export of the stored gas, this nozzle comes
complete with an anti-vacuum grid to protect the sealing membrane
during depressurisation. Depending upon the operation process, the inlet
and outlet nozzles maybe a shared connection.
7. Shell drains: Allow condensates within the gasholder gas space to drain
away in seal pots. The seal pots are designed to maintain the pressure with
the gasholder.
8. Shell manways: Used for maintenance access into the gas space – only
used whilst the gasholder is out of service.
9. Earthing bosses: To ensure that the gasholder is safe during electrical
storms etc.
10. Volume relief pipes: Essential fail-safe system to protect the gasholder
from over-pressurisation. Once actuated, by the piston fender, the volume
relief valves allow the stored gas to escape to atmosphere at a safe height
above the gasholder roof. As the volume relief valves open they actuate a
limit switch.
11. Volume relief limit switches: Used to send signals to the control room to
confirm the status of the volume relief valves.
12. Contents scale: On the gasholder shell is a painted scale displaying the
volume of gas stored within the gasholder. An arrow painted on an

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adjacent level weight indicates the current status. Also painted on the
scale is the location of the piston in relation to the shell access doors.
13. Tank roof: The roof is designed to withstand the local climatic conditions
and the possibilities of additional loads, such as snow and dust. The roof of
the gasholder is of thrust rafter radial construction and has a covering of
single sided lap welded steel plates. The roof has various accessories
attached including:
a) Turret: Allows air to enter and exit the gasholder as the storage
volume changes.
b) Roof vents: Small nozzle around the periphery used for the
installation of the seal.
c) Roof manways: Allows access down to the piston fender when the
gasholder is full.
d) Circumferential hand railing: Safety hand railing around the outside
of the roof.
e) Radial walkway: For access from the staircase to the centre vent etc.
f) Volume relief valve actuators: Mechanical arms that operate the
volume relief valves once the piston fender reaches a certain level.
g) Load cell nozzles: For maintenance access to the load cell
instrumentation used for volume recording purposes.
h) Radar nozzles: For maintenance access to the radar instrumentation
used for volume recording purposes and piston level readings.
i) Roof interior lighting nozzles: For maintenance access to the
gasholders interior lights.
Figure 2.3 : Interior View of Gas Holder Roof

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2.3.3 Piston
The gasholder piston moves up and down the inside of the shell as gas enters and exits the
gasholder. The weight of the piston (less the weight of the level weights) produces the
pressure at which the gasholder will operate. The piston is designed to apply an equally
distributed weight to ensure that the piston remains level at all times.
Figure 2.4 : Piston of Gas Holder
As the piston is designed
without dead space, the
accumulation of any
substantial explosive gas air
mixture during starting-up or
shutting-down is practically
impossible. Furthermore,
this design offers effective
protection against damage
due to low pressure.
The piston is guided
vertically by two rings of
rollers located in a vertical
spacing of approximately
1/10 of the holder diameter
at the piston assembly.
Figure 2.5 : Guide Roller, Oil Seal, Truss like Piston of a Coke
Oven Gas Holder

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The rollers run on the column guide bars on fixed rails which are held firmly by the
polygonal construction of the holder shell. Horizontal rotation of the piston is prevented by
two tangential guides movable in radial direction. With this type of piston guide, the
difference in the pressure arising during the change of the piston movement is only a few
millimetre water gauge (mm.w.g).
Normally, the construction weight of the piston does not suffice for the adjustment of the
required gas pressure. Therefore concrete weights have to be evenly distributed on the
piston deck.
Figure 2.6 : Concrete Weights

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The piston made up of the following sub-elements:
1. Piston Deck: The outer annular area is formed from butt welded steel plates
resting on steel section rest blocks. Lap welded steel infill plates form a dome
profile to withstand the gas pressure in the gas space beneath it. For higher
pressure gasholders the infill plates are lap welded on both sides, whereas, low
pressure gasholders are only welded on the top side. The fully welded piston deck
forms a gas tight surface, which rests on the piston support structure when the
gasholder is depressurised. The following ancillary items can be found on the
piston deck:
 Piston manway: Used for maintenance access below the piston into the gas
space – only used whilst the gasholder is out of service.
 Load cell chain: A receptacle for gathering up the load cell chains as the
piston rises.
2. Piston fender: The fender is a steel frame structure that is fixed to the piston deck
annular plates and acts as a support structure for the abutment plates. Access can
be gained to the top of the piston fender from either the shell access doors or
roof manways depending on the gasholder volume. Attached to the piston fender
are the following items:
 Piston walkway is a platform around the top of the piston fender equipped
with safety hand railing, used for inspection purposes.
 Piston ladders are rung ladders complete with safety loops for access to the
piston deck from the piston walkway.
 Radar reflector plates are used to bounce the radar signal back to the radar
instrument for volume indication recording and piston level readings.
 Abutment plates are fixed to the outside of the piston fender to form a
circumferential surface for the sealing membrane to roll against whilst the
piston moves during operation.
 Piston torsion ring around the base of the piston fender is a torsion ring
which helps keep the piston shape during pressurisation. Concrete ballast can
be added to the torsion ring to increase the weight of the piston and
subsequently be a cost effective way to increase the pressure of the
gasholder to the required level.
Piston Walkway
Piston Ladders Abutment Plates
Figure 2.7 : Piston Fender

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2.3.4 Sealing
The seal of the gasholder is designed to operate in the conditions specified by the client
and to suit the stored medium. It is the key for gas holder with piston to prevent the gas
leakage through the sealing which set around the edge of the piston. Sealing rubber is
pushed to the shell plate by the counter weight through lever, and follow the small
undulation of the shell plate. Sealing oil is to be held in the area between shell and piston.
Oil falls down to the bottom through the tiny gap between the sealing rubber and shell,
and pumped up by oil circulation system.

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CHAPTER
3
WIGGINS TYPE GAS HOLDER
3.1 Introduction
Wiggins type Gas Holder is a dry-seal gas holder.
The seal of a Wiggins type gas holder is made of rubber.
A dry-seal gasholder can be designed to have a gross (geometric) volume ranging from 200
to 165,000 m3 (7,100 to 5,800,000 cu ft), whilst having a working pressure range between
15 and 150 millibars (1.5 and 15 kPa).
The dry- seal gasholder is finished with an anti-corrosive treatment to counteract local
climatic conditions and also any chemical attack from the stored medium.
This anti-corrosive treatment is fully compatible with the sealing membrane and also the
environment.
Figure 3.1 : Erection of seal in progress

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3.2 Stage Wise Operation
Figure 3.2 : 1. Gasholder Piston at Rest Position, seal hanging loose, incoming gas starts to
press seal against the piston fender abutment plates.

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Figure 3.3 : 2. Gasholder Piston at Rest Position, gas pressure forces seal against side of
piston fender abutment plates, holder now at gas pressure.

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Figure 3.4 : 3. Piston starts to move upwards, seal rolls off piston fender and gas pressure
forces seal against inside of shell plates.

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Figure 3.5 : 4. Piston continues to move upwards, seal continues to roll off piston fender
and gas pressure forces seal against inside of shell plates.

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Figure 3.6 : 5. Piston continues to move upwards, seal continues to roll off piston fender
and gas pressure forces seal against inside of shell plates.

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Figure 3.7 : 6. Piston approaches its maximum position, seal is now almost all forced
against inside of shell plates.

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Figure 3.8 : 7. Piston now nearly at its maximum position, seal is completely forced
against inside of shell plates, seal “pops” as tight fold is removed.

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Figure 3.9 : 8. Piston now at its maximum position, seal is completely forced against inside
of shell plates, volume relief system is activated, gas is released to atmosphere and alarm
is sounded.

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Figure 3.10 : 9. Piston now lowered from its maximum position, seal is in normal
operation.

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Figure 3.11 : 10. Piston lowering, seal in normal operation and range of use.

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Figure 3.12 : 11. Piston now at bottom of travel, but gasholder still at gas pressure - any
more gas removed will now reduce gas pressure and require the seal to be “popped”
again.

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Figure 3.13 : 12. Further removal of gas pulls the seal over the inlet/outlet main and
suction seals the exit, thereby preventing a vacuum forming in the holder. The holder seal
now has to be “popped” again.

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CHAPTER
4
M.A.N TYPE GAS HOLDER
4.1 Introduction
Tata Steel, Jamshedpur is presently executing expansion of their existing plant at
Jamshedpur under 3 MTPA Expansion Project. In the expansion project new Coke Oven
Battery Nos. 10 & 11 will be installed. In order to cater to the increased CO gas generation
and proper distribution, one number new CO Gas Holder of capacity 50,000 m3 along with
the accessories and mountings will be installed.
The optimised use of fuel gases generated in the steel plant is important for efficient
energy management. The by-product gases generated (i.e. Coke Oven Gas) will be utilised
as fuel for various heating applications of the steel. Balance available gases will be utilised
in power plant for steam and power generation.
The gas holder is Water less, Oil sealed type.
The Gas Holder shall be provided in the networks mainly for storage of fuel gas and to meet
the peak requirements of different consumers.
The Job includes construction of new CO Gas Holder, design, engineering, manufacture and
assembly. Supply at site, erection testing, and commissioning of the CO Gas Holder
complete with all accessories after dismantling of old existing BF Gas Holder. The
inlet/outlet nozzle & ducting “U” Seal and one Quick Isolation Valve, electrics,
instrumentation and controls, air conditioning and ventilation systems, fire fighting systems
and water system shall be provided.
All equipment shall be complete with approved safety devices. These items shall include
not only those usually furnished with elements of machinery but also the additional covers,
guards, cross-over, stairways, ladders, platforms, handrails etc. which are necessary for
safe operation of the equipment.

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4.2 Objective of the Project
Tata Steel has expanded its capacity from 6.8 MTPA to 10 MTPA in Jamshedpur. As a result
there is substantial increase in generation of Coke Oven gas. The existing Coke Oven gas
network is insufficient to take the increased load and the process fluctuations in the
different systems. Very often, the network pressure fluctuates and such a usable fuel gas is
flared into the atmosphere to maintain the set pressure. Therefore, it was envisaged to
construct a Coke Oven Gas Holder of desired capacity which will hold and release the Coke
Oven gas into the network as per process demand. As a result of this huge money loss can
be avoided to minimise the flaring of such usable gas into the atmosphere.
Figure 4.1 : Block Diagram of CO Gas Flow
CO Gas holder acts as a buffer between generating unit (Exhauster outlet) and consuming
unit (Booster inlet) to ensure steady pressure at gas booster inlet, Exhauster outlet &
Coke Plant battery under firing gas header.
In absence of CO Gas holder, exhauster delivery pressure is maintained by flaring CO gas
(either though clean gas bleeder or from battery top flares).
The CO Gas holder is required for Coke Plant process. Steady CO gas pressure at exhauster
outlet, booster inlet & Coke Plant under firing gas header is required to ensure proper
heating of ovens. If exhauster outlet pressure fluctuates the exhauster suction will also vary
& thereby battery under firing CO Gas pressure. This has serious impact on battery heating.
Because of variation in CO Gas pressure there is reduction / loss in pushing.
There are many intangible losses in terms of pressure fluctuation at consumer end as well
as health of battery top equipment's.
Avg. gen - 180000Nm3
/hr

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4.3 Operation Principle
The gas enter into the gas holder from the bottom, when the gas pressure bigger than the
piston weight, the piston raise, when gas is used, the piston fall, the pressure of gas is
3.5±0.15KPa, the piston raise or fall according to the gas inlet or ourlet.
The gas holder set lower limit alarm and lower lower limit alarm with interlock, avoiding
the internal negative pressure, also set high limit alarm and high high limit alarm with
interlock, avoiding the piston rushing top. Some online instrumentation are set to monitor
the gas holder operation, e.g. temperature, pressure, leakage, etc. Besides these info can
be indicated at site, the signals can be transmitted to control room, with interlock control
as well as inlet/outlet valve.
The lighting system and thunder proof are equipped for the gas holder body.
The inlet/outlet pipe entry the gas holder from the bottom, the U shape seal is used for
sealing the gas in case of maintenance.
Sealing Oil Recycle System: A tailor-made of sealing oil is used to seal the gas, the oil
trench level between piston and side plate is bigger than gas pressure, and the oil flow
along the gap between the wall and pressure plate to oil groove on the bottom, then to the
oil-water separator in pump station, then after separation, pump to top oil tank, then flow
to the oil trench, so that form an oil cycle.
OIL
CYCLE
Oil
Groove
Oil-Water
Separator
in Pump
Station
Top Oil
Tank
Oil
Trench
Figure 4.2 : Oil Cycle

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4.4 Main Parameters
Table 1: Main Parameters of COGH
1 Capacity 50000 m3
2 Diameter of Inscribed Circle 37251.1 mm
3 Diameter of Circum Circle 37715 mm
4 Side Plate Length 5900 mm
5 Piston Stroke 46.02 m
6 Ring form walkway platform 5 Level
7 Quantity of Column 20
8 Guide Roller 40 sets
9 Distance between upper and lower guide roller 3525 mm
10 Anti-rotary Device 2 sets
11 Height of Gas Holder Wall 56.907 m
12 Total Height 63.024 m
13 External Elevator 1
14 Cage 1
15 Inclined Ladder 1
16 Emergency Salvation 1
17 Volume indicator 1
18 Bottom Area 1098.9 m2
19 Gas Pressure 3.5±0.15 kPa
20 Pump Station 3
21 Top Spare Oil Tank 3
22 Oil Pump System 3
23 Weight of Oil Seal 75000kg
24 Inspection Glass 6
25 Side Plate Thickness 6 mm
26 Bottom Plate Thickness 6, 8 mm
27 Piston Bottom Plate Thickness 6 mm
28 Roof Plate Thickness 4 mm
29 Walkway Plate Thickness 6 mm
30 Inlet/Outlet Pipe Size DN1200
31 Condensate Water Drain System 1 set
32 Safety Venting System 12 sets
33 Blow Venting System 2 sets
34 Emergency Venting 1 set (DN500)
35 Air Blast Pipe 1 set
36 Sidewall Manhole 8
37 Radar Height Indicator 2 sets

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CHAPTER
5
ERECTION & INSTALLATION
5.1 Foundation Check and Acceptance
Confirm the origin point according to the foundation drawing.
Ascertain the centre point, steel rod centre; check is there any missing items of civil work.
Foundation Survey: By using theodolite at the gas holder centre put mark plates on the 4
position of perpendicular to foundation, angel: 0°, 90°, 180°, 270°, measure and mark the
foundation centre in each 90° area. Measure the foundation horizontal level by level gauge,
also check by steel ruler, the distance from the centre to each pre-buried point, centre ring
radius R1.
Ascertain the elevator shaft centre, and measure the foundation level.
Ascertain the foundation settlement point.
Figure 5.1 : Foundation Check and Acceptance

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5.2 Erection and Installation Work
5.2.1 PHASE I
5.2.1.1 Starting the 1st phase
The 1st phase starts from ascertaining the origin point to jacking preparation work
completed.
5.2.1.2 Ascertain the origin point
1) Lay out cross coordinate from the foundation centre, use theodolite to mark the 4
points of angel 0°, 90°, 180°, 270°, mark chord length between 4 points L1. Then
mark the each same chord length L2 within the 90° area.
2) Use theodolite to measure each mark point position and divide equally, ascertain the
chord length L2 to check the point position.
3) Ascertain the distance from the mark point centre to column slide plate centre.
Figure 5.2 : Ascertaining Origin Point

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5.2.1.3 Laying the bottom plate
1) Install the gas inlet/outlet pipe and drainage pipe according to drawing.
2) Remove the rust of bottom plate, leave 30mm of welding part without painting and
lay the plate to the foundation. Meanwhile take note of the process.
3) According to the drawing, the laying process shall be from the centre to the two
sides. The welding line shall be visually checked first, if approved then vacuumed
check, the negative pressure is 500mm H2O. Also check the flatness of bottom plate.
4) The centre of bottom plate shall have a tapping hole for steel rod and measuring.
5) Remove the rust and painting on the welding line.
5.2.1.4 Erecting the 1st section column
1) Assemble the 1st section column on the platform, until the entire column base is
finished, line out the centre line and base line on the slide face, the temperature
compensation shall be considered while adjusting the column.
2) Lifting the marked column base to the position above the foundation bolt sleeve,
adjust the column base elevation by tilted pad steel.
3) Adjust the distance between marked block centres to slide rail centre line.
4) Check the column verticality, column elevation bias, adjacent column elevation bias
by calibrated theodolite, the bias shall be controlled within ±0.5-1.0mm, after the
tolerance meets the requirements, tighten the bolt and proceed the 2nd pouring.
5.2.1.5 Installation of bottom oil ditch plate
1) Lay, spot weld the bottom oil ditch plate, install the 1st layer side plate, strength the
column and prevent the oil ditch plate deformation.
2) Weld the oil ditch plate, check the welding line, if approved by visual check,
vacuumised or oil permeate test, if approved, paint the welding line.
3) According to welding process, weld the bottom plate, oil ditch, 1st layer side plate,
and column base together as a whole part.
4) Fix and weld the piston supporting.

Page | 42
5) Lift the centre ring temporary platform pre-assembly to the bottom centre, and
make the necessary fasten.
6) Manufacture the roof centre ring on the site platform according to the drawing.
7) Lift the centre ring by auto crane, the auto crane shall be as close to the centre as
possible, ensure the lifting success one time, then use theodolite, plumb line to
adjust, use lifting jack to adjust the height, control the elevation bias, centre bias,
radius bias, and radial bias.
5.2.1.6 Installation of blow fan
Install the blow fan and other auxiliary parts beside the 1st side plate.
5.2.1.7 Installation of 2nd column
Install the 2nd long column, connect the 1st long column with base column, adjust the
dimension to specification and consider the shrinkage by welding. Then install the 4th layer
side plate temporarily.
5.2.1.8 Piston installation
1) Manufacture the piston truss on the platform and pre-assemble.
2) Lift the centre ring to the position by mobile crane, adjust the dimension by hand
hoist.
3) Lift the 1st piece of truss into the jug, support the truss by temporary supporting
tools, adjust the verticality and radius length. After adjustment, connect with centre
ring by bolt and weld, then process the 2nd piece of truss with same procedure, also
weld with 1st piece truss, then assembly the rest of truss.
4) Lay the painted piston plate on the truss according to the drawing, spot welding first,
then weld the whole plate, reduce the truss deformation, if visual check approved,
test the welding line by suds when jacking.
5) Install the still oil tank, walkway, fence and so on.
6) The jacking process shall be supervised. Check and note the bolt mechanism wrap
circumstance.

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5.2.1.9 Bird Hook execution work
1) After completing the piston system installation, install the bird hook above the
piston, which is used for supporting the top truss and connecting the piston, drop
down the top truss by lifting jack, fasten the top truss with bird hook by bolt, then
buckle the piston and top truss, keep it solid enough. The piston bears the top truss
load through bird hook.
2) Grind the column interface, side face and the side plate interface. The slide interface
shall be smooth. Check the column slide face and elevation total lean degree.
5.2.1.10 Top truss installation
1) Manufacture the top truss on the platform and pre-assembly. Control the hole
dimension tolerance during drilling. Lift the top truss to the position where one side
on the 20 sets bird hook, on the other side weld with centre ring, then lift the truss
of opposite position, adjust the truss on the supporting plane, fasten all truss pieces
and weld with centre ring together.
2) Lift the top plate from jug outsides, spot welding first and then weld all plate
according to specification.
3) Mark the install position of roof cowl and internal cage on the top truss.
4) Pre-assemble the cage frame on the ground, lift to the position and install it,
meanwhile install the cage shaft, platform and stairs.
5) Put internal cage ready for installation.
6) Lift the cowl ring, then install the ventilation device of pre-assembly, meanwhile
avoid leaning by rope. Then weld and fasten.
7) Construct the cowl rain plate. Install the plate in sequence, spot welding first and
then weld the whole plate.
8) Install the top truss walkway, emergency salvation device.
9) Install the column scaffold on top roof.
10) Install the column guide device on top roof.
11) External scaffold construction.

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12) Internal scaffold construction.
13) Construct the roof car, which is used for installing the column, side plate and so on.
14) The jacking process shall be supervised; check and note the bolt mechanism wrap
circumstance.
5.2.1.11 Piston guide wheel installation
1) While installing the piston guide wheel use spring wheel on one side and fixed wheel
on the other side. For avoiding welding shrink use fixed type upper wheel and
change the spring type to fixed type temporarily.
2) When guide wheel in place, adjust by pad plate, the contact force between column
and guide wheel shall reach to the extent that hand power can’t rotate. The wheel
opposite the column shall not lean to one side, meanwhile, adjust the verticality and
make sure that the centre line of guide and column coincide.
3) Firstly install the upper wheel, until the sealing device finished, install the lower
wheel. Make sure the centre line of upper and lower guide rail, and wheel within
specified tolerance.
5.2.1.12 Sealing device installation
The necessary materials like canvas, woods, spring, and slide plate shall be well prepared,
weld these parts to oil ditch plate, install the slide plate, adjust the level, install the angle
block, control the block match size. The block shall contact tightly with wall. Then install
woods, canvas, lug and other parts. After assembly, the canvas shall be protected during
the jacking process, the sealing device shall be assembled well.
5.2.1.13 Side plate
Install the 2nd to 8th layer side plate symmetrically by top car, adjust the dimension if
necessary, and, then weld.

Page | 45
Figure 5.3 : Erection of COGH in Progress

Page | 46
5.2.2 PHASE II
5.2.2.1 Starting of 2nd Phase
The Phase II starts from jacking process. Install all side plates, top truss and piston break
away. Then the piston lands to the bottom.
5.2.2.2 Piston plate sealing test
Blow up the fan, keep the piston floating and then put the suds on the welding line to
check the gas tightness.
5.2.2.3 Jacking
Blow the compressed air into the gas holder, lift the top truss and external scaffold by one layer
side plate height, install bird hook and temporary fixed plate on the column, hook the top truss
with piston, blow out the air, top truss and piston weight is supported by column.
Install the side plate under this condition, repeat the process until complete all side plate.
Before blowing air, flowing items shall be carefully check:
a) Is there any side plate missing welding?
b) Roof car is located in symmetrical position.
c) Scaffold and side plate have no contact.
d) Guide wheel and column have no foreign matter.
e) The sealing device has no foreign matter.
f) The column inner face is well polished.
g) The bird hook fixed plate is well installed.
h) The power source shall be cut off except air blower; the cable to the roof shall have
flexible allowance.
i) The communication device is normal.
j) Piston and scaffold have no problem when lifting.

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5.2.2.4 Column Connection
The column connection work is performed at the column assembly platform, and at the
suitable height.
1) Assemble the connection tool at the
column top end, and keep the
connecting area clean and without rust.
2) Lift the upper column and connect with
lower column by tool, and fasten by
bolt, check its verticality.
3) Following the welding specification,
weld the outer area first and then weld
the interface area.
4) Grind the slide face, use straight ruler to
check the interface area, and see is it
necessary to rework, replace the formal
bolt by temporary bolt.
5.2.2.5 Side plate assembly
The side plate assembly shall follow the symmetrical principle.
1) The side plate would be distribute evenly around the gas holder, to avoid
deforming, damage, it should put on the slippers, and remove the rust and paint.
2) Take record when every side plate assembly is finished.
3) The special tool is used for lift the side plate. Top rail car lift the plate
symmetrically, and use temporary bolt.
4) Strengthen plate is assembled after the side plate assembly, and fasten by bolt.
5) Spot weld after centre ascertain.
6) Weld through the plate.
7) Take out the temporary bolt after welding, punch hole by 17mm, insert the 16mm
pin, weld and polish smoothly.
Figure 5.4 : Column Connection

Page | 48
8) Side plate assembly shall follow the specification, and interface area shall be
smooth.
9) During the side plate assembly, assembly the venting line, elevator shaft and
ladder shall be at the same time.
5.2.2.6 Walkway assembly
1) The walkway assembly is performed at the centre position of external scaffold.
2) Assemble the straight corridor, handrail and other accessories on the ground.
3) All lower section of scaffold is fixed at the side plate. The walkway assembly can
make use of it.
4) Perform the welding process
5) After completing the whole assembly work of this layer disconnect the scaffold from
the side plate, then jacking, and then recover the scaffold at the upper layer.
5.2.2.7 Upper side plate and its accessories assembly
1) Upper side plate, eaves board assembly, top truss and column connection:
a) Remove the external scaffold.
b) The last layer of side plate and upper accessories are assembled by special
scaffold.
c) Remove the bird hook and top truss connecting bolt, jack is used to jack up
the top truss to position.
d) Top crane is used to lift the eaves board, connect the board, column and top
truss together and weld.
2) Accessories assembly
At the same time assemble the following accessories:
a) Emergency venting line
b) Window and glass.
c) Volume indicator.

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d) Upper oil tank platform.
e) Salvation equipment, steel rope.
f) Piston guide wheel.
g) Remove the temporary power supply.
h) Upper scaffold dismantle.
In the meantime, painting and instrumentation work can be performed simultaneously.
5.2.2.8 Piston Fall Down
1) Before falling the piston, the following work shall be prepared well:
a) The industrial power cable substitute.
b) The piston guide wheel dimension adjustment.
c) Clean the side plate inner side.
d) Remove the bird hook.
e) Paint the top truss inner face, side plate inner face; adjust the elevator,
cage and salvation device to the working condition.
2) Falling down the piston by opening the manhole, clean the side plate inner face.
3) Assemble the external elevator, and internal cage.

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5.2.3 PHASE III
5.2.3.1 Starting of 3rd Phase
The erection work phase III is start from the piston falling to the end.
5.2.3.2 Check the sealing device
After the piston falling to the ground, clean the oil ditch, check the sealing device
completely, check if the canvas has burned point by welding splash, or inclusion inside,
rework or replace according to the condition, and make some necessary modification.
5.2.3.3 Adjust the piston guide wheel and installation
Dismantle the guide wheel used in Phase II, which not comply with the drawing, clean, and
install the spring, fixed wheel, make necessary adjustment. In order to prevent the piston
slanting, or rotating, the guide wheel shall keep balance force to column.
5.2.3.4 Piston commissioning
After check the sealing device and guide wheel, inject water to bottom oil ditch to check
the leakage. Clean the bottom oil ditch and piston trench and then drain out the water.
Re-inject the water to the certain level, and inject the oil to ditch, start the pump and
make the oil to design level.
After the overall work complete, blow air into the gas holder, and run the whole system.
Following items shall be check during running the gas holder:
1) Pressure fluctuate ≤150Pa
2) Piston slanting: sunshine: ≤D/500, cloudy: ≤D/1000
3) Horizontal rotating gap.
4) The oil level in each cabin has no obvious diversity.
5) The pump maximum start time: on average less than 3, each time last 5~10 min.
6) Piston running condition: no vibration, no abnormal sound.
5.2.3.5 Gas holder tightness test
Running the piston, and check every parameters meet the specification, then blow in air
jack the piston, reach in certain volume, keep the pressure by 7 days, inspect the volume,
atmospheric pressure, gas holder inside and outside temperature, gas holder insider
pressure, calculate the leakage every day. Check and take record each pipe tightness,
pump running condition and other data.

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5.3 Lifting Proposal
The erection of gas holder is different with other projects. It has its characteristics, some
pre-manufacture parts transport from manufactory to erection site, and gas holder is high,
erected by side plate layer by layer needing a big amount of lifting work, so the special
lifting equipment is needed. Here roof car is used. It can move around the roof and is used
to lift the side plate, column, walkway and other parts, in addition, a big size crane shall be
used to lift truss and unload the equipments placed outside the gas holder. In addition, an
8-12 ton auto crane is used to regular lifting work.
To ensure the lifting work safety, there should be a 10m wide road to be compaction
around the gas holder.
5.3.1 Bottom plate laying and base column lifting
1) 16Ton auto crane is used to lift the bottom plate through 4 points to the foundation
face. Then lay the plate, after removing the rust and paint turn the plate and weld.
2) Weld the base column and foundation bolt first and then lift the base column to
position by 16 ton auto crane.
5.3.2 Truss Lifting
1) The truss is one of the key parts for lifting work, as the truss is of big weight, big
lifting range, so before the truss being assembled, the platform position and crane
position shall be carefully selected according to the actual situation to ensure its
safety operation. The lifting work applies “one piece by one piece” principle, big
crane lifts the truss into the gas holder, support by special tool, equipped with
wheel, and pushes the truss to position. The erection work shall start at the
position opposite the crane, in the meantime; lift the support platform and roof
centre ring.
2) The roof centre ring is the biggest lifting part, weight is 12 ton, lifting height is 10
m, so lifting the centre ring shall be previous to lifting truss, and the capacity of
crane shall not be less than 90ton placed outside the gas holder and near the
foundation ensuring lifting one time success.
5.3.3 Roof Truss and Roof Plate Lifting
1) 25 ton capacity or more, 4 joints crane is used to lift the top truss, around the gas
holder.
2) After complete the roof truss, lift the roof plate from 4 points around the gas
holder.

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5.3.4 Column, side plate, elevator shaft lifting
After completing the roof, assemble the roof crane to lift the column, side plate, platform
and elevator shaft.
5.4 Welding Specification
5.4.1 Basic Requirement
1) The welding worker shall have welding certificate.
2) The worker shall follow the drawing and the welding specification. The welding
method is hand arc welding, E4313, E4303 and E4315 welding rod is used to weld
carbon steel.
3) Before welding, worker shall check the assembly and welding area condition, if it
doesn’t meet the requirement, welding work can’t allowed until rework well. After
welding, the splash and slag shall be removed and take record.
4) If welding rework need, the defect reason shall be found and rework measures
would be taken.
5) The welding worker takes responsibility of the welding quality, for some high
difficulty welding line, worker shall follow the instruction of technical engineer to
ensure the quality.
5.4.2 Welding Material and Management
1) Welding rod shall have clear mark, quality certificate and approved by inspector,
then can be used. And the welding rod shall stock in dry, ventilate room.
2) For the welding rod covering has crack, spalling, eccentricity bigger than 3%, core
wire has rust, which can not be used, it should be rejected or disposed.
3) Stoving:
 Acid welding rod is dried by 75~150℃, 1hour.
 Alkaline, low hydrogen welding rod is dried by 350~400℃, 1~2 hours, then
put into 100~150℃ constant temperature box.

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5.4.3 Preparation work
1) Check the welding area dimension, especially the fillet, root gap, groove dimension.
2) Remove the water, rust, dirt and paint in welding area.
3) The spot welding material is as same as formal welding, normally the interval is
150~300mm, the small diameter welding rod shall be used, the spot welding point
shall be firm, crack, gas hole, inclusion or other defects are not allowed.
4) The welding groove match up shall use special tool, spot weld carefully.
5) Check the spot welding quality and assembly condition, if qualified, then formal
welding can process.
5.4.4 Welding
The acid welding rod can use AC and DC welding machine, alkaline low hydrogen welding
rod use DC welding machine. For plate thickness less than 5mm, the rod diameter shall be
less than 4mm.
1) The welding sequence principle is from centre to 2 sides symmetrically, spot
welding first, then formal welding.
2) In case one of following circumstances happen, the welding can’t processed unless
effective protective action is taken:
a) The welding temperature lower than -10℃.
b) Wind speed more than 10m/s.
c) Rain or snow d) Relative humidity higher than 90%.

Page | 54
3) Welding current parameters shall be as follow:
Table 2 : Welding Parameters
Welding Rod
Type
Welding Rod
Diameter
(mm)
Current (A)
Flat
Welding
Vertical
Welding
Horizontal
Welding
Overhead
Welding
Acid
3.2 100-130 90-120 90-120 90-120
4 160-200 120-160 120-160 120-160
Alkaline Low
Hydrogen
3.2 90-120 90-110 90-120 90-110
4 160-180 120-150 120-150 120-150
4) Bottom Plate Welding:
Bottom plate is divided into
middle plate, edge circle
plate, and oil ditch, the
middle plate can be divided
into 4 areas as A, B, C, D,
weld the plate within the
area first, then weld the line
between areas, then weld
the edge circle plate, and oil
ditch, weld the middle plate
with circle plate, finally weld
the balance welding line. As
shown on drawing, weld
short line first and then weld
the long line during welding
middle plate.
No matter welding short line or long line, the sequence shall start from centre to
side, back step welding and skip welding shall be applied.
While welding the circle plate and oil ditch, workers shall follow the symmetrical welding
principle, start from the centre to side.
Figure 5.5 : Layout of Bottom Plate Welding

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5) Column Welding
The erection precision for column is very high and has direct relationship with
piston movement.
To ensure the column verticality, two measures shall be applied to prevent column
deformation:
a) Anti-deformation way: While matching the upper and lower column, the
upper column can lean outward 3/1000 degree.
b) Rigid fixed to prevent deformation.
Welding process requirement: For the 1st layer use Ф3.2,E4315 rod, current is 110~130A,
and for the other layers use Ф4 rod, current is 160~180A, multiple layers to flat.
6) Side Plate Welding
According to the symmetrical position principle, assemble the side plate around the
gas holder by temporary bolt, spot weld first, back welding from side plate centre to
two ends. Every layer welding work is done by 10 workers. Every worker is
responsible for welding 2 sides side plate, first weld plate with odd number, then
even number, Ф4mm, E4303 rod is used, process the welding one time.
7) Column and side plate welding
The weld work shall be symmetrically distributed, vertical weld from the upper side
plate bolt position, two sides downwards at the same time. Then take out the
temporary bolt, clear and insert pin, weld from the inner and outer surface, then
grind the weld line to flat.
8) Piston Bottom Plate Welding
The piston bottom plate can be divided into 5 areas along the radial direction, first
weld the circle direction, then weld radial direction, the spot welding sequence shall
start from centre to end, however leave 150~200mm not welded near the main
frame area.
The radial welding sequence is a-2, b-2, c-2, d-2 and e-2, from the centre along with
the arrow direction, and welding must process symmetrically at the both sides of
main frame at the same time, after finish the radial line, then weld the balance
150~200mm circle line, the welding line size and quality shall follow the
specification.

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9) Roof Plate Welding
Classify and code the welding line similar to layout, divided into 4 areas A, B, C, D
along radial direction.
Welding starts from area B opposite position, and from centre to two sides,
temporary location, then weld along the B1 circle direction, not weld window glass
area. Then weld B2 welding line in B area, and weld left and right roof plate
alternately, continuous welding one plate is not allowed.
Welding the C, A and D area as same as area B.
Weld the window glass after completion of the roof plate.
5.4.5 Welding Quality Requirement
1) The butt weld for bottom chord of piston truss, centre ring, bottom and top chord
of roof truss and centre ring shall comply with GB50205-2001 “Acceptance Rules of
Steel Structure Construction”, Class II, the corner weld shall comply with Class III.
2) The weld for bottom plate, oil ditch, piston bottom plate, and side plate must be air
and oil proof, inspection for bottom plate welding line is by gas oil, check all welding
line by vacuum method, (negative pressure to 500mm H2O), inspection for piston
bottom plate, side plate by gas oil or suds. All inspection is performed by
professional worker.
3) The visual check for truss line and side plate corner welding line shall comply with
GB50205-2001, Class II, balance comply with Class III.

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5.5 Erection Quality Control
5.5.1 Foundation Recheck
The foundation recheck is be conducted by main contractor, construction side, and civil
work contractor 3 parties together.
1) Foundation Plan Dimension:
a) The tangential tolerance for centre line of foundation and axes is ±5mm
b) The radial tolerance for centre line of foundation and axes is ±5mm
c) The radial tolerance for roof ring beam is ±3mm
d) The width tolerance for foundation is ±10mm
2) Foundation Elevation
a) The tolerance for top elevation is -3mm
b) The flatness tolerance for top is 5mm
c) The tolerance for piston support area is ±1.5mm
d) The tolerance for tar sands elevation is -15mm
e) The tar sands elevation at zocle position shall be as same as concrete.
f) The tolerance for foundation of oil-water separator is -10mm.
3) Foundation pre-buried parts
a) Tolerance for anchorage beam, height: ±3mm, horizontal: ±5mm.
b) Tolerance for bottom mark plate, radial: ±12mm, tangential: ±10mm.
c) Tolerance for pre-buried bolt: radial: ±5mm, tangential: ±5mm

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5.5.2 Side Plate Assembly Control
1) Tolerance for length L: ±2mm.
2) Tolerance for height H: ±1.5mm.
3) Tolerance for height flatness Δ≤1mm.
4) Vertical bend along length direction: ±1mm, flat bend: ±2mm.
5) No crack at corner area.
6) The offset between layer side plate≤1mm.
7) The flatness for each layer ±2mm.
8) Enlarge hole and forced assembly are not allowed.
5.5.3 Bottom Plate Quality Control
The final bottom plate flatness tolerance is (+60mm, -40mm)
Vacuum check all bottom plate welding line, 100% lot.
5.5.4 Base Column Quality Control
1) The tolerance for base column is
shown on the drawing:
Table 3 : Base Column Quality Control
2) The elevation tolerance for base
column is ±1mm.
3) The neighbour column elevation tolerance is ±1mm
4) Verticality (radial, tangential) ≤h/5000 (h: base column height)
A B C
+2mm,
0mm
≤0.5mm ±1mm
Figure 5.6 : Base Column Quality Control

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5.5.5 2nd column and others quality control
1) Verticality tolerance, radial: ≤h/1250, tangential: ≤h/2000 (h: column height).
2) The neighbour column elevation tolerance is ±2mm
3) The neighbour column distance: ±2mm
4) Check before lifting the column, if bend or defect, it must be rectify.
5) The column interface tolerance: radial Δ0.5~1mm; tangential: Δ0.5~1mm
5.5.6 Roof frame Quality Control
1) Centre ring, ovality: ±5mm
a) The centre offset ≤5mm.
b) The distance from ring bottom face to bottom plate: +30mm
2) Truss cornice elevation: ±5mm
a) Truss span: ≤5mm.
b) Truss bend: ＜L/1000.
c) Horizontal distance between truss end: ±4mm
3) Roof verticality: H/5000 (H: the distance between highest point of gas holder to
bottom plate)
5.5.7 Piston Quality Control
1) Centre ring differential: ovality: ±5mm
a) The centre offset ≤5mm
b) The distance from ring bottom face to bottom plate: +20mm
2) The span tolerance ≤5mm
3) The tolerance for oil ditch assembly Top: ±5mm; Bottom: ±2mm; Flatness: ±2mm

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5.5.8 Sealing Device Quality Control
1) The dimension for piston oil trench shall comply with design specification.
2) The position for slide plate: ±1mm
3) The gap between slide plate and side plate: ≤0.5mm
4) The gap between corner slide block and slide rail: ≤0.3mm
5) The total gap between corner slide block and clapboard shall be within 4~6mm,
(each side).
6) The horizontal tolerance: ±1mm/side, ±2mm/circle.
7) The spring point: ±1mm, working length 117+12mm, the pressing force shall
comply with requirement.
8) The canvas shall comply with specification, no leakage.
5.5.9 Guide Wheel Quality Control
1) The tolerance for centre line for upper and lower guide wheel base and rail centre
line is ≤2mm.
2) The tolerance for upper guide wheel centre line and lower guider wheel centre line
is ≤2mm.
5.5.10 Piston Running Test
1) Blow the air into gas holder, keep the pressure 350mm H2O, speed as
0.2~0.5m/min and go through the whole range twice. Then go through one time by
0.6~0.8m/min.
2) During piston running, it shall has no block, no abnormal sound, no jump, upper
and lower guide wheel can rotate smoothly, under even stress.
3) Piston inclination: inspect the inclination at 4 points of piston, the incline of piston
at any direction shall be: sunshine day: ≤89mm, cloudy: ≤44mm

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5.5.11 Gas Holder Tightness Test
Gas pressure: 350mm H2O
Capacity: 45,000m3 (Air)
Air inflation time: 7 days
Leakage rate: ≤2%.
Figure 5.7 : Blower for Tightness Test

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5.5.12 Erection Sequence Chart
Cowl erection,
welding
Roof erection
1st
column erection,
welding
2nd
-9th
layer side plate
erection
1st
-9th
side plate painting,
inspection
10th
-91st
layer side plate
erection, painting
Eave plate erection
Remove bird support,
roof crane etc.
Preparation Work
Foundation check, allocation
Bottom plate welding,
check
1st
layer side plate erection
Bottom oil ditch welding,
piston support assembly
Piston truss assembly
Piston sealing, anti-rotation
erection and commissioning
Roof truss, support and roof
plate erection, welding
All temporary tools,
equipments ready at
site
Assembly Platform
Adjust jacking tools
Piston bottom plate, oil
ditch side plate laying
and welding
Piston walkway, oil tank,
bird support erection
Piston truss
welding
Roof frame, roof
truss welding
Blow air make piston
lifting, water supply
test
Clean and Check
Piston sealing
commissioning
Running Piston
Overall Commissioning
Air tightness test
Hand over to TaTa
Elevator shaft erection
Clear out the
construction tools
External scaffold
erection
Roof support remove
Walkway, ladder,
venting line, etc
erection
Remove blow
station

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CHAPTER
6
PLANT OPERATION & MAINTENANCE
6.1 Configuration and Function
6.1.1 50000m3 Oil Sealed Gas Holder
1) STEEL STRUCTURE
The thin oil is used as medium to seal the coke
gas, the gas holder consist of side plate,
bottom plate, column, roof structure, roof
plate, cowl, maintenance platform, piston,
pressure block, seal mechanism, spring guide
wheel, fixed wheel, wind resistance girder,
ring form walkway, inclined ladder, external
elevator, cage, as well as other accessories. In
general, the structure is all welded steel
structure.
The gas holder body consists of
bottom plate, side plate, column, cowl,
inclined ladder and ring form walkway. The
polygon gas holder side plate is folded plated,
with thickness 6mm, outer set wind resistance
girder, ring form walkway and inclined ladder,
each walkway and roof can be reached
through ladder. The width of ring ladder
is 800mm. The 6mm thick riffled plate is
used for walkway and ladder, the side plate of bottom part is 8mm thick, centre plate is
6mm thick. The side plate is connected with column, the column is made of I beam,
considering the construction load, the column is connect with foundation bolt by bolt
sleeve.
The roof structure consists of roof structure, roof plate, cowl and inside upper and lower
maintenance platform. The thickness of roof plate is 4mm. the cowl is set on the top,
which is used for air flow above the piston and maintenance worker on the walkway.
Figure 6.1 : 50000m3 CO Gas Holder

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The piston consists of piston plate, piston frame, spring wheel, fixed wheel and anti
rotary device. The piston plate is also folded plate seems like side plate, thickness is
6mm. piston frame is space girder, the centre is internal elevator platform, the sealing
mechanism contacting with side plate is oil seal.
Piston frame wheel and anti-rotary device: guide wheel are equipped above and below
the piston frame, along with the column direction, the spring wheel is set along the
south direction, fixed wheel is set along the north direction, both set anti rotary device,
prevent the piston horizontal rolling.
Piston frame supporting: the supporting device is set on the bottom plate, used for the
maintenance work when the piston land on the bottom plate.
3 oil proofing plate is set on the piston corresponding to the upper oil tank location,
preventing the oil splashing onto the piston.
Figure 6.2 : Anti-rotary Device
Concrete weight block: the weight block is used for balancing the gas pressure inside the
holder, the block is located beside the piston walkway.
2) External inclined ladder: It is located outside the gas holder, used for maintenance
work.
3) Side Manhole: Quantity is 8, located on the side plate row 1~5, evenly around the
circle, which are used for enter into the gas holder at construction or maintenance
phase.

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4) Piston Manhole: Quantity is 2, symmetric distributed on the piston plate.
5) External Elevator, Cage, Manual Emergency Salvation:
External elevator: Circle shape elevator, the
machine room located on the ground, connected
with each ring walkway by connecting platform, the
distance between each floor is 10.53m (＜11m. It is
used for transferring worker from ground to roof to
inspect or maintenance.
Cage: It is used for transferring worker from roof to
piston top, the machine room is outlay type.
Manual Emergency Salvation: in the event of cage not working, it can lift the worker
from piston to roof lower platform.
6) Piston Sealing Mechanism: It is consist of slide block, slide plate, canvas, spring, wood,
and hanging mechanism, used for seal the gas.
7) Upper Spare Oil Tank: The capacity for upper oil tank can maintain 4 hours operation in
case of black out.
8) Safety Venting Pipe: Quantity is 12, DN300, it is
enough to ensure the gas holder safety in case of
piston exceeding the height limit.
Figure 6.3 : Internal Elevator Cage
Figure 6.4 : Safety Venting Pipe

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9) Blow Venting Pipe: Quantity is 2, DN159, thickness is 6mm, it is used for blowing during
maintenance, sample taking during replacement.
Figure 6.5 : Blow Venting Pipe
Figure 6.6 : Temperature
Indicators

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Figure 6.7 : Parts of COGH
Upper Spare Oil Tank
Blow Venting Pipe
Riser Tube
Safety Venting Pipe
Main Inlet/Outlet

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10) Emergency Venting Pipe: Quantity is 1, DN500, it is used for discharge the gas in gas
holder in case of emergency.
Figure 6.8 : Emergency Venting Pipe
11) Blow Pipe: Quantity is 1, DN325, thickness is 6mm, it is used for commissioning and
maintenance.
12) Inspection Glass: Quantity is 6, upper 3 and lower
3, located near the upper oil tank and lower oil
trench. It is used to measure the oil level from
outside the holder.
Emergency
Venting Pipe
Figure 6.9 : Inspection Glass

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13) Volume Indicator: Quantity is 1, mechanical type,
indicating the gas volume.
Figure 6.10 : Volume Indicator

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6.1.2 Electric System
The annual active electric consumption is 376650 KWh.
Lighting system including: 1st platform, top platform, ladder, roof walkway, volume
indicator, machine room of elevator, etc.
Electric distribution: external elevator, cage, oil pump, motor valve, and water pump. Main
electric equipment uses emanate connecting type.
Control system: including oil pump, local equipment switch on/off, oil level interlock
control and pump start count and status display. The control of elevator is supplied by sub-
contractor.
Thunder proofing: thunder proofing area is setting on the roof, lead a line connected with
ground. Elevator machine room, pump station and other accessories equipments use
dedicated earth line.
Main electric equipment list:
Table 4 : Electric Equipment List
No. ITEM
1 Oil Pump Motor
2 Elevator
3 Cage
4 Hydraulic Quick Shut Off Valve
5 Motor Butterfly Valve DN1200
6 Motor Valve DN500
7 Drainage Pump

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6.1.3 Control System
A radar detector is equipped for monitor the piston position, meanwhile monitor the gas
volume, output 4~20mA signal, and set high and low limit alarm and interlock.
The volume indicator is mechanical type, with passive contact far eas tone.
The piston oil trench has level transmitter, monitor the oil level and ensure the gas sealing,
meanwhile monitor the piston inclination.
The top spare oil tank has oil level alarm, when the level is not enough, the worker in
control room will receive information to add the oil.
There is gas detector located on the piston, cowl, pipe inlet/outlet platform, the control
room will receive alarm in case of leakage.
There is pressure transmitter in pipe inlet/outlet and inside the holder, and installed in the
site protective box.
The platinum resistances are set at the entry pipe and gas holder.
The U water seal room has gas detector, in case that the gas leak, interlock with ventilation
fan, ensure the gas density can’t reach to explosion level, meanwhile alarming the worker
in control room.
Pump station has level transmitter, monitor the oil level and alarm the high and low level.
Nitrogen pipe, pressure air pipe, low pressure steam pipe has pressure switch and meter,
when the pressure low, alarm the control room.
Water pipe has water meter, monitor the water consumption. The control room and
electric room has fire and fume detector, in case of fire, alarm the control room.
The control room has PLC cabinet and electric cabinet, PLC cabinet is hardware for control
system, electric cabinet is distribution for power supply.
The control station is human-computer interface, display various parameters and alarms,
and remote control the valves.

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Figure 6.11 : Control Room

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Figure 6.12 : Working Circuit of COGH

Page | 74
6.1.4 Valves, water seal and pipeline
Process flow: The coke oven gas pressure, after purification, is 3.5~5.0Kpa, the Max. gas
flow is 50000mg/Nm3, temperature is 10~60℃, first go through DN1200 anti-explosion
electrical butterfly valve, then DN1200 hydraulic quick shut off valve, then U shape water
seal, finally enter into the gas holder from bottom.
Figure 6.13 : Motorized Butterfly Valve, Blind Plate and Hydraulic QSV
Considering the installation, operation, and maintenance convenience for quick shut off
valve and electrical butterfly valve, the pipeline out pit are supported by steel structure,
the water seal and condensate water are drain out to pit by stainless steel pipe, then flows
to separator tank and finally pumped to industrial water system.
Hydraulic QSV
Motorized
Butterfly Valve
Blind Plate and
Blind Plate Ring

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Blind plate and blind plate ring: for sure the DN1200 quick shut off valve can be
maintenance or repair on safe condition, the blind plate and blind plate ring are set up
after the electrical valve, in normal working condition, blind plate ring is working; in the
event of the quick shut off valve need maintain or repair, first inject water into the water
seal, cut off from the gas holder, then close the
electrical valve, open the venting line, change the
blind plate ring into blind plate.
U water seal: The injection water volume is 12m3
per time, fill up water time: 30min.
The inlet/outlet pipe is DN1200, entry from the
bottom, one pit, there is water collect tan inside
the pit, above the pit has a construction room,
inside has gas detector.
The condensate pipe is made of stainless steel
pipe, when the tank water level reach to high
limit, the pump will start to work, drain the water
into separator tank automatically, finally pumped
to industrial water system.
Figure 6.14 : Installation of
Underground U Water Seal
Figure 6.15 : Installed Underground U Water seal

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6.1.5 Water supply and fire fighting water
6.1.5.1 Water Supply
Water source: DN150 water pipe, pressure ≥0.2Mpa shall be provided at T.O.P.
Water consumption: the make up water for U water seal is 25m3/h, water for bottom oil
ditch is 8 m3/h, considering the 10% more unexpected, the maximum water consumption
volume is 36.3 m3/h.
Water supply design: the water pipe for U seal and bottom oil ditch are all come from steel
plant water system, and the pressure fulfil the requirement of most negative point.
Sewage system: the sewage is completely distributary principle. The oil-water separator
sewage volume is 0.2m3/h, maintenance sewage volume is 1.0m3/h, the pit sewage
volume is 8m3/h, the sewage tank size is 1200*1200*2400, inside the tank has a
submersible sewage pump (WQB25-10-2.2), N=2.2KW, with anti-explosion electric control
cabinet and level auto-control device, as well as level alarm. The sewage will drain to
separation tank, then pump to industrial water system.
Rain water: the rain water in this region is collected by gravity into water mouth, finally
flow to rain water pipeline.
6.1.5.2 Fire fighting water
Water source: one source point DN150,
pressure＞0.45Mpa.
Water consumption: 20L/s, considered as 3
hours fire.
Outdoor fire fighting water system: the fire
fighting water line is layout around the gas
holder, the circular pipeline has 3 fire
hydrants SS100-1.0, equipped with QZ19
straight steam nozzle, 2 pc, canvas pipe,
20m, 2pc, and pump start button, which
inside a box.
Fire extinguisher: near the gas holder,
inlet/outlet pipe pit room, elevator
machine room, electric distribution and
control room, equipped with certain number of transportable and portable CO2 ammonium
phosphate fire extinguisher.
Figure 6.16 : Outdoor Fire Fighting Water System

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6.1.6 Air condition and ventilation system
Electric distribution room, control room shall use individual air condition to keep the
suitable temperature, ensure the instrumentation can work properly.
The inlet/outlet pipe pit has emergency ventilation, and interlock with gas density alarm.
The elevator machine room and pump station has forced ventilation.
6.1.7 Oil seal system
The oil seal system consists of piston seal, pump station, oil pipeline and top spare oil tank.
1) Piston Seal:
It consist of flat side seal mechanism, angle seal mechanism, oil trench
drainage device, slide plate draw device, still oil trench and chamber sealing
mechanism. The piston oil trench is divided into 6 parts by chambers. Oil flows along
wall from top oil tank to oil trench, then still oil trench, bottom slide plate, and spring
sleeve, finally collected in bottom oil ditch.
Figure 6.17 : Oil Flow from the Top Oil Tank to the Oil Trench.

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Synthetic Partition Apron
Oil Flowing in the Oil Trench
Oil Filled in Oil Trench
Figure 6.18 : Sealant in COGH

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The flexible steel slide strip suspended on the inner wall of the piston trough to allow slight
flexibility, are pressed against the holder shell by numerous contact elements. The flexible
joint between guide bars and piston consists of a specially woven fabric of a tough and
sufficiently impermeable texture which is not adversely affected by the sealing liquid. The
wooden fender prevents possible damage of the main sealing fabric which could otherwise
result in unforeseen friction of fabric and steel.
This sealing fluid runs in a thin film slowly along the holder shell and thus forms, at the
same time, an extremely durable corrosion protection against the aggressive components
of the gas.
Figure 6.19 : Sealing Mechanism

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Sealant Circuit:
The sealing liquid flowing down the holder shell is collected, together with any condensate,
in the bottom sump which is heated in winter where the two fluids segregate due to the
difference in specific gravity and the water separation properties of the sealant itself.
The fluids flow to the collecting tanks (according to the circumference of the gas holder) in
which on the one hand outlet of the condensate is effected and on the other hand feeding
of the sealing liquid, free water, into the circuit is affected by means of appropriate devices.
Small pumps working intermittently and switching ON and OFF, controlled by a float,
convey the sealing fluid to the overflows on the upper shell edge through riser pipes from
where the fluid flows back into the piston trough. These overflows are combined with
spare vessels which contain such a sufficiently measured quantity of sealing liquid not
included in the circuit that in the event of any possible power failure, the gas holder will be
supplied from the same for a longer period and thus, can be kept operating.
Of even greater importance is the function of the oil film during winter operation. The rime
formed at low ambient temperatures from condensed water vapour cannot settle directly
on the holder shell and slowly become a thick ice layer because of the oil intermediate
layer. It finds no surface contact and drops into the heated trough where it melts and drain
off to the outside as water.
Figure 6.20 : Sealant Circuit

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This action is mechanically supported by the razor-edged, slanting edges of the slide strips.
A solid ice deposit on the holder wall is thus impossible. In the case of a sealing liquid with
a specific gravity below 1, the condensation water forming on the shell of the piston space
would drop immediately in the oil in the piston trough. In the front chamber formed by the
partition apron, the large water drops are led below between the slide strips and shell
directly into the bottom trough. Any small suspended drops or any possible suspended
contamination from the piston space will be led off after a certain time all will deposit
respectively. The rear chamber with the press-on elements is, in all cases, kept free from
water and contamination. To equalize the fluids in the front and rear chamber, a vessel
connected via a connecting pipe is arranged in which water and contamination drop down
as only very little liquid movement take place.
The above shows that no water can collect in the seal. Thus, freezing of the moving
elements during winter operation and consequent in daggering of the sealing function is
avoided. All sealing elements remain accessible during operation and can be checked.
In special cases, pressure of the sealing stripes can be adjusted by means of counterweight
levers or by springs and sleeves.

Page | 82
2) Pump Station:
There are 3 sets pump station, each pump station including oil-water separator and 2
recycle pump(1 working 1 standby), pump is screw type. The oil flow from bottom oil
ditch to oil-water separator, water drain out station, the oil level pump to top oil tank
when the level reach to certain level.
Figure 6.21 : Gas Holder and Pump House connection for Oil Flow
Riser Tube
Man Hole
Gas Holder oil trench and
Pump House Connection

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Oil-Water Separator Tank
Figure 6.22 : Pump House

Page | 84
3) Oil tank: Located on the top of gas holder, can maintain 4 hours use when black out.
Figure 6.23 : Inside View of Oil Separator Tank

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CHAPTER
7
OPERATION PHILOSOPHY
7.1 Preparation work before commissioning
1) Check gas pipeline, ready for receiving gas.
2) The gas holder tightness test has qualified and auxiliary facilities are ready.
3) Check all valves on gas pipe, nitrogen gas pipe, steam pipe working well, individual
commission is completed.
4) Check pumps in pump station can work well both in auto and hand condition.
5) Check the piston oil trench at required level.
6) Check the bottom oil ditch level.
7) Check the blind plate valve and electric butterfly valve in closed condition.
8) Check the side wall manhole, piston manhole and drainage valve in closed condition.
9) Check all valves on venting line in closed condition.
10) Check all instrumentation, electric equipments in good condition.
11) Check overflow pipe at drainage pipe.
12) Check the nitrogen gas source.

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7.2 Nitrogen gas exchange air
1) Check the quick shut off valve is on closed condition. (Or close the electric butterfly
valve, open the quick shut off valve, exchange the nitrogen gas through DN50).
2) Check the drainage valves (2 pc) at U water seal, inflow valve DN100 and overflow
valve DN150 are all in closed condition.
3) Check the drainage valve of gas holder DN100 in closed condition.
4) Check the DN500 valve of emergency release in closed condition.
5) After all valves mentioned above are checked, and in closed condition, pipe connect
the DN50 interface and DN80 nitrogen source with a pipe, then open the valves to
start the air exchange, the pressure is controlled at 500 kPa, after the process is
finished, close the valve at DN80, then close the valve at DN50, and remove the
pipe.
7.3 CO gas exchange nitrogen gas
1) Check the overflow pipe DN150 for U water seal and the drainage pipe DN100 of
gas holder is filled with water or not. In normal condition, the two points mentioned
above shall be filled with water when doing the test for U water seal, otherwise,
more water shall be added until full.
2) Check the valves again.
3) Open the quick shut off valve, then open the electric butterfly valve slowly by hand,
introduce the CO gas into the pipe, keep the pressure at 500 kPa, when the
exchange process qualifies close the valves at venting line, increase the pressure,
when the pressure rise to 3.5kPa, the piston starts to lift. Adjust the electric
butterfly valve to control the piston lift speed. As long as the piston lift every 10m
high, check and if all systems are working well, and then change the electric
butterfly valve from hand mode to electric mode.
4) Check and if all system working well, open the DN150 drainage valve of U water seal
and DN100 valve of gas holder in sequence, turn to normal working condition.
5) After the exchange process finish, break the pipe between nitrogen source and gas
holder interface.

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6) Test the gas sample inside the gas holder, if the O content less than 1%, open the
inlet valve slowly and let CO gas into gas holder, adjust the valve and keep the
pressure not less than 500 Mpa.
7) After the gas approve the test and explosion test, then close the venting valve and
blow valve.
8) Keep the blow pressure higher than gas holder 1 Kpa during the exchange process.
9) Nobody is allowed stay on the piston during the exchange process.
7.4 Normal working condition
1) DN1200 quick shut off valve and electric butterfly valve are all in open condition.
2) DN500 emergency releasing valve is in close condition.
3) DN150 drainage valve of U water seal and DN100 drainage valve of gas holder are in
open condition.
4) The water inlet valve DN100 for U water seal, and overflow valve DN150 are in close
condition.
5) When the piston reach to high high limit position, interlock with quick shut off valve
and turn it close, in case of problem with quick shut off valve make the piston
continue to rise and pressure keep increasing, open emergency releasing valve
DN500, when the piston drop to high position, close the DN500 valve.
6) When the piston drop to low low limit position, interlock with quick shut off valve
and turn it close, in case of problem with quick shut off valve, make the piston
continue to drop and the pressure keep decreasing, close the DN1200 electric
butterfly valve.
7) In normal working condition, the worker shall carefully control the piston position,
especially for the high high limit. The control parameters shall be fixed during the
commissioning phase, as long as it is fixed, it can’t be changed without
authorization.

Page | 88
7.5 Maintenance and repair on plan (Nitrogen exchange CO)
1) Check all valves are in working condition.
2) The piston shall drop slowly, close the quick shut off valve and electric butterfly
valve.
3) If the gas system can’t receive all gas in the holder, first close the quick shut off
valve and electric butterfly valve, then open the emergency venting line, make the
piston drop slowly to position. Close the DN500 emergency valve, keep the pressure
500 Kpa ready for exchange.
4) When the exchange process is finished, open the DN100 valve and inject water into
the U seal, then close the drainage valve DN150 and DN100, and open the overflow
valve DN150, about 15-30 min later, when the overflow pipe has water, it means
the U water seal is filled, turn down the valve DN100, make sure the overflow pipe
has water drip, the gas holder will be completely isolated with CO gas pipeline, then
the worker can do the maintenance work.
5) After the maintenance work finished, first close the DN100 valve, stop inject water,
open the drainage valve DN150, discharge all water in the seal, check that U seal is
empty, close the drainage valve DN150, close overflow valve DN150. Turn to
nitrogen gas exchange air process.
7.6 Emergency condition
1) If the gas holder leaks or is on fire, first close the DN1200 electric butterfly valve,
cut off the gas source. Open the DN500 emergency releasing valve quickly, release
the gas inside the gas holder, shorten the fire time.
2) Connect the DN50 interface and DN80 nitrogen gas source, blow the nitrogen into
the gas holder and pipeline. Keep the micro-positive pressure, prevent the air going
into the gas holder and explode.
3) When the fire is extinguished and piston drops to position, the nitrogen exchange
process is basically finished. Close DN500 valve quickly, continue to blow nitrogen
into the gas holder, until the inspection for the exchange process finished, exchange
the gas according to No. 4) and 5) in Item 7.5.

Page | 89
4) The gas holder shall urgency stop at following circumstances:
a) Piston slant seriously.
b) The sealing oil falling too quickly.
c) Piston oil trench level too low.
d) Gas volume less than piston low limit, or piston lay to the ground.
5) How to operate in black out situation:
a) Report to the leader and inform the electric engineer to repair.
b) Electric engineer checks the electric distribution system and repair.
c) Check all items if it is working well.
d) Use the spare oil tank to keep the oil level. If the black is out too
long, close the pump station, keep the positive pressure, and
exchange the nitrogen gas.
6) If obvious metal friction sound is found, maybe the piston is slant or guide wheel is
blocked:
a) Keep the pressure, maintain the gas holder, report to relevant
department.
b) More than 2 workers with oxygen mask go into gas holder for
inspection.
c) If the column is slant, close the inlet/outlet valve.
d) If the piston is slant, keep the piston level, adjust the counter weight,
rectify the piston position.
e) If the anti-rotary device or guide wheel is blocked, adjust the gap
between guide wheel and column.

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7.7 Position and responsibility
Operation and maintenance worker shall monitor all running parameters closely, take
record every hour and save a period of time. The running parameters includes: gas volume,
piston position, gas pressure, temperature, piston speed, gas pressure at inlet/outlet pipe,
gas density above the piston, piston oil trench level, oil pump start times and duration, etc.
Keep a close communication with gas source department, when the gas source is
abnormal, report to superior department.
Keep a close communication with gas consumer, watch the gas consumption and pressure
variation.
Workers shall find out the reason and deal with the problem at once when receiving the
alarm signals, meanwhile report to superior department.
Calibrate the meters regularly, when the deviation between volume mechanical indicator
and electrical meter exceed the set value, workers shall find the reason and correct.
In normal operation, the safety venting pipe shall not release the gas.
Before stopping the gas holder, the piston landing speed shall comply with the following
rules:
 When the distance from piston to bottom is more than 10m, the dropping speed is
as normal.
 When the distance from piston to bottom is between 5m and 10m, the dropping
speed shall be less than 0.5m/min.
 When the distance from piston to bottom is between 2m and 5m, the dropping
speed shall be less than 0.3m/min.
 When the distance from piston to bottom is less than 2m, the dropping speed shall
be less than 0.2m/min.
 When the piston land to the bottom, the gas source shall be cut off completely.

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7.8 Pay special attention
1) When the piston continues slant seriously, worker shall find the reason and settle.
2) When the piston guide wheel, or limit guide wheel have abnormal sound with side
wall, worker shall analyse and solve the problem.
3) The gas holder shall run the whole piston route every quarter.
4) In case of black out, the operating gas holder shall be as follows:
a) Start the spare oil tank.
b) Check how long will take for power supply.
c) Worker staff shall evacuate the gas holder except the spare oil tank
operator.
5) In case of the piston rushing top, measures shall be done as follows:
a) Maintain the piston oil level and reduce the gas volume.
b) Adjust the valve and control the piston falling speed.
c) When the piston lands, find the reason and clean the splash oil.
6) Negative pressure is not allowed inside the gas holder at any time.
7) The guide wheel, anti-rotary device, anti-corrosion, elevator, oil tank, oil-water
separator, oil pump, oil pipeline, valves and other equipments shall be maintained
and repaired at regular time, the instrument meter shall be calibrated regularly.
8) Check and inspect the sealing oil regularly.
9) In normal operation, the counter weight block can’t move without authorization.
10) The alarm parameters and protective values of gas holder or auxiliary devices can’t
be changed without authorization, and alarm sound and light signals can’t be
turned off.
11) All worker staff must be trained before going to work.

Page | 92
CHAPTER
8
SAFETY RULES
Working in the gas holder area is full of danger and so the following safety rules must be
followed:
1) Before inspecting the gas holder, the evacuation route must be clear.
2) Before going into the gas holder, following principles must be complied with:
a) The rebreather’s pressure and volume must be confirmed well.
b) The gas density above the piston shall be in reasonable range.
c) Check the external elevator and cage working well, limit switch
effective and accurate.
d) The external elevator and cage shall be operated by trained worker
staff.
e) When there is worker on the piston, a specially-assign worker shall
supervise the cage operating platform.
f) Check the urgency salvation device safe and usable.
3) Piston check shall be applied by 2 workers, equipped with at least CO gas detector,
interphone and rebreather.
4) Before and after internal check, worker shall report to responsible leader.
5) Worker can’t go to or go inside the gas holder in thunder weather condition.
6) Before going into the pump station, the axial flow fan shall start and detect the gas
density.
7) Workers shall fix the appliance or tools when put it on or near the piston sealing
mechanism.

Page | 93
8) Following shall be paid special attention during maintenance:
a) The maintenance worker shall be well trained and informed with the
hazard source, and location of safety exit and urgency salvation device.
b) Working certificate and fire work licence shall be issued.
c) Gas holder inside work shall be performed at least 2 workers, equipped
with CO gas detector, interphone and rebreather. Special worker shall
supervise the process.
d) In bad weather condition, the maintenance work cannot be performed.
e) In the event of endanger of the worker safety, maintenance work shall stop
immediately.
f) Before maintenance work, the grease dirt on the walkway shall be cleaned
completely. Before fire work, flammable things shall be clear or firmly
protected.
g) During maintenance of the gas holder roof, all tools shall be fixed well.
h) The lighting device voltage shall be less than 12V during maintenance of the
internal gas holder.
i) While maintaining the piston guide wheel, the worker shall be equipped
with safety belt, and reliable hanging mechanism.
9) The adjustment of gas pressure shall comply with following requirements:
a) The working pressure after adjustment shall be less than the design
pressure.
b) The piston oil trench level shall meet the requirement of pressure after
adjustment.
10) In case of fire on the pump station sealing oil, the pump shall stop immediately;
switch off the inlet/outlet oil pipe valves, cut off the power supply, use fire
extinguisher or sand to put out the fire.
11) If the condensate water leaks from the foundation, it shall be blocked up.

Page | 94
CHAPTER
9
CONCLUSION & BIBLIOGRAPHY
9.1 Conclusion
Gas Holder is an important part of an Integrated Steel Plant. Presence of gas holder in a
plant:
1) Maintain the pipe network at steady pressure during dynamic imbalance between
supply and consumption acting as a buffer.
2) Avoid losses of usable CO gas generated from the Coke Oven, Blast Furnace and LD
System.
3) Increase the production efficiency of the plant.
4) Economic Benefit: The losses incurred due to flaring of usable CO gas are very high.
So, installing a gas holder benefits the company economically.
5) Developing a gas holder in a factory also helps it to be eco-friendly.
6) Absence of gas holder has an adverse impact on specific energy consumption.

Page | 95
9.2 Bibliography
1) Safety standard of Tata Steel
2) http://www.tatasteel.com/
3) http://www.motherwellbridge.com/
4) http://en.wikipedia.org/wiki/Gas_holder

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