1. ACKNOWLEDGEMENT
‘’Knowledge is incomplete without implementing it in practical
terms’’
With this view, I would like to express my deep sense of gratitude to the
respected and learned guides of OIL AND NATURAL GAS CORPORATION
LIMITED, Sivsagar for providing their painstaking and untiring supervision.
I am thankful to Mrs. Ruprekha Baruah, Dy. Manager (HR). RTI, ONGC,
Sivsagar for giving me the opportunity to undergo my winter training in ONGC
and to learn deeper the basics of production in a GAS COMPRESSOR PLANT.
I also express my sincere thanks to Shri Santanu Medok, SE (P), ST-
GLK, ONGC, Nazira for providing me a conducive environment and necessary
facilities, allowing me to reach the desired accomplishment.
I am heartily thankful to all the Managers, Engineers and all Shift
Operators working under them to give me direction and valuable inputs on each
and every sections of production related.
Lastly, I am also thankful to all those invisible hands, which were indirectly
linked with my project and helped me in successful completion of my project.
BIDHAN DAS
5th Semester
(MECHANICAL ENGINEERING)
DUIET, DIBRUGARH
2016
2. CERTIFICATE
This is to certify that the project report on the winter project at Surface
Team, ONGC Nazira is a genuine record of work done by Bidhan Das of
Mechanical Engineering Department of 5th Semester of DIBRUGARH
UNIVERSITY INSTITUTE OF ENGINEERING AND TECHNOLOGY
(DUIET), Dibrugarh University under my guidance in partial fulfilment of the
requirement for the B.Tech Degree. The project was held from 4th January, 2016
to 3rd February, 2016 for a period of one month.
During the above period, his attitude towards learning was excellent and I
found him very sincere towards the work assigned.
I wish him all the best in his future endeavour and a bright future ahead.
MENTOR
MR S. MEDOK, SE(P)
Surface Team, ONGC, Nazira
3. CONTENTS
INTRODUCTION
HISTORYOF ONGC
OBJECTIVE OF ONGC
CURRENT ACTIVITIES
VISION & MISSION
ONGC ASSAM ASSET
INFRASTRUCTURE
ONGC OFFICES
WHAT ONGC DOES
ONGC GELEKY FIELD
MILESTONES OF THE GELEKY FIELD
GAS COMPRESSION PLANT
GCP-1
GCP-2
GCP-3
WORK OF A MECHANICAL ENGINEER
MAINTENANCE
STARTUP & SHUTDOWN PROCEDURE
SAFETY
CENTRAL WORKSHOP. SIVSAGAR
DIESEL SHOP
ONGC DRILLING RIG
CONCLUSION
REFERENCES
4. INTRODUCTION OF ONGC
Oil and Natural Gas Corporation Limited (ONGC) (incorporated on 23rd
June, 1993) is a
NavratnaPublicSectorUnit (PSUtype) PetroleumCompany,underthe administrativecontrol of the
Ministryof PetroleumandNatural Gas(MoP&NG) of Governmentof India.Itisa Fortune Global 500
company ranked 335th
, and produces 77% of India’s crude oil and around 81% of its gas. It is India’s
largest oil and gas exploration and production company. Indian Government holds 74.14% equity
stake in the company.
ONGC was founded on 14 August 1956 as a commission by the Government of India and
headquarteredinDehradun,India. It is involved in exploring for and exploiting hydrocarbons in 26
sedimentary basins of India. It produces about 30% of India’s crude oil requirement. It owns and
operates more than 11,000 kilometres of pipelines in India.
ONGC has fully owned subsidiary. Its international subsidiary, ONGC Videsh Ltd (OVL)
currently hasprojects in15 countries andlooksforexplorationof oil & gas inRussia,Iran,Iraq, Libya,
Myanmar and othercountries includingdevelopmentof alarge gas fielddiscoveredby it in Vietnam
offshore.
Recently ONGC has made 6 newdiscoveries at Vasai West (oil & gas) in Krishna Godavari
Offshore,ChinnewalaTibba(gas) inRajasthanandLaiplinggaon(oil & gas) and Banamali(oil) both in
Assam. ONGC has many matured fields with a current recovery factor of 25-33%.
ONGC is India’s largest producer of crude oil, natural gas and LPG. ONGC India also
produces other value added petroleum products such as NGL, C2-C3, Aromatic Rich Naphtha and
Kerosene.
Operations
ONGC’s operations include conventional exploration and production, refining and
progressive development of alternate energy sources like coal-bed methane and shale gas. The
company’s domestic operations are structured around 11 assets (predominantly oil and gas
producing properties), 7 basins (exploratory properties), 2 plants (at Hazira and Uran) and services
(for necessary inputs and support such as drilling, geo-physical, logging and well services).
Products and services
ONGC suppliescrude oil,natural gas, and value-added products to major Indian oil and gas
refining and marketing companies. It primary products crude oil and natural gas for Indian market.
Today, ONGC is the flagship company of India, and making this possible by a dedicated
teamof nearly33,000 professionalswhotoil roundthe clock.Itis thistoil whichamplyreflectsinthe
aspirations and performance figures of ONGC. The company has adopted progressive policies in
scientificplanning,acquisition,utilization,training and motivation of the team at ONGC, everybody
matters,everysoul counts.ONGChasa unique distinctionof beingacompanywithin-house service
capabilities in all the activity areas of exploration and production of oil & gas and related oil field
services.
5. HISTORY OF ONGC
The developmentof the oil industryinIndiawasthe dreamof Pandit Jawaharlal Nehru and
his dream has come true now. His vision has become a reality and this has been made possible by
ONGC.It wouldnothave beenpossible withoutthe vision and foresight of Pandit Jawaharlal Nehru
and Shri Keshava Deva Malaviya, the Father of Indian Oil Industry.
During the Pre-Independence period, the Assam Oil Company in the north-eastern and
Attock Oil Company in north-western part of the undivided India were the only oil companies
producingoil in the country, with minimal exploration input. The major parts of India sedimentary
basins were deemed to be unfit for development of oil and gas resources.
After Independence, the National Government realized the importance of oil and gas for
rapid industrial development and its strategic role in defence. Consequently, while framing the
Industrial Policy Statement of 1948, the development of petroleum industry in the country was
considered to be of utmost necessity.
It was in 1956 that oil was first commercially struck at Digboi making the beginning of Oil
productioninIndia.Itwas inAugust1956 that the Oil & Natural Gas Commission (ONGC) was set up
withthe task assignedtoplanpromote andimplementprogramsforExplorationand Exploitation of
petroleum resource throughout the country.
ONGC first started with exploration in the foothill of Himalayas and the Cambay basin.
Some gas wasdiscoveredatJwalamukhi andoil atCambay.Discoveryof the Ankleshwarfieldin !959
ledto the firstcommercial production of the oil by ONGC in August 1961. The first offshore well on
albeit structure was supported by Indira Gandhi on March 19, 1970. Indira Gandhi then said,
“Two of the main reason for the rise and fall of the nations are the discovery of new
resources and emergence of new technologies. This is a day of joy to all of us. It is a step which will
take the country forward.”
Afterthe formationof Oil & Natural Gas Commission,GovernmentdecidedtoconvertOil &
Natural Gas Commission into a public limited company and to offer to a natural gas commission, a
public equity of the new company. Simultaneously a new company Oil & Natural Gas Corporation
Limited was incorporated as a public limited company under the Company’s Act 1956 on the 23rd
June, 1993.
During March 1999, ONGC, Indian Oil Corporation (IOC) a downstream giant and Gas
Authority of India Limited (GAIL),the only gas marketing company agreed to have crossholding in
each other’s stockto pave the way forlongterm strategicalliance amongstthemselves,bothforthe
domestic and overseas business opportunities in the energy value chain.
6. OBJECTIVE OF ONGC
Optimize production of hydrocarbons
Self-reliance in technology
Environment technology
Promoting indigenous effort in oil and gas related adequate resources of environment
Development scientifically oriented and technically competent human resources through
motivating training.
CURRENT ACTIVITIES:-
Oil & Natural Gas Corporation produces oil, natural gas and value added products. It
is engaged in all the facts of exploration & production activities; which include seismic
survey, drilling oil and gas field development production and related engineering activities.
The company owns operates 23 inland seismic crews, one offshore seismic vessel. It has
instituted 7 R&D centres catering to various E&P activities including engineering and safety
needs, and one institute for human resource development (ONGC Academy) at Dehradun.
OVL has 39 projects spread over 16 countries across the globe with 9 producing assets in 7
countries namely Sudan, Russia, Vietnam, Syria, Brazil, Columbia and Venezuela.
VISION & MISSION OF ONGC
To be a world class Oil & Natural Gas Company integrated in energy business with
dominant Indian Internship and global presence. The missions of ONGC are:
Dedicated to excellence and by leveraging competitive advantages on R&D and
technology with involved people.
Imbibe high standards of business ethics and organizational values.
Abiding commitment of safety, health and environment to enrich quality of
community life.
Foster a culture of trust, openness and mutual concern to our people.
Strive for customer delight through quality products and services.
7. ONGC ASSAM ASSET:-
ONGC started production in Assam Asset in 1957 and spudded the first wild Cat Act
in Disangmukh in 1957. Based on the results of geo-scientific surveys, drilling of Rudrasagar
prospect was taken up in 1960, which proved to be commercially viable hydrocarbon
accumulation. Subsequently by, Lakwa field was discovered in 1964 and Geleky field in
1968. The continued search for oil and gas led to the discovery of many other small fields
such as Demulgaon, Lakhmani, Changmaigaon, Laiplingaon etc. The fields of the assets are
Rudrasagar, Geleky and Lakwa. The fields are in Sivsagar district in Assam. The installation of
these fields located within a radius of about 50 km from the cities of Sivsagar and Nazira.
The Headquarter of Assam Asset is situated at Nazira and Sivsagar is the district
headquarter. The Assam Asset of ONGC produced 1.4 MMT of crude oil and 367.63
MMSCMD of gas during 2004-05.
INFRASTRUCTURE:-
ONGC’s success rate at per with the global norm and is elevating its
operation to the best in class level, with the best in class level, with the
modernisation of its fleet of drilling rigs and related equipments.
ONSHORE OFFSHORE
Production Installation: 240 Well Platforms: 160
Pipeline Network (km): 17500 Well cum process platforms: 5
Drilling Rig: 69 Water Injection Platform: 7
Work over rigs: 59 Process platform: 22
Well Stimulation unit 99 Well stimulation unit: 7
Seismic survey crew: 34 Drilling rigs: 9
Logging units: 32 Pipeline Networks (km):4500
Engineering Workshop: 2 Offshore supply vessels: 73
Virtual reality centre: 5 Multipurpose supply vessels: 6
Regional Computer Centre: 5 Seismic vessels: 1
8. CURRENT OFFICES OF ONGC
WHAT ONGC DOES?
The main operation of ONGC involves Exploration and Production of crude oil and
natural gas from different parts of India and supply the downstream oil and gas companies
like Indian Oil Corporation Limited (IOCL) and Gas Authority of India (GAIL) for further
processing and marketing. In India, there are several places like Assam, Mumbai, and Gujrat
etc. where oil and gas reservoirs are available in onshore and offshore fields. The main
function of ONGC is to find those places, drill there and collect those gases and oils. From
where a mixture of oil, gas and water is collected and supplied to GGS (Group Gathering
Station). In GGS, the mixture is initially sent to separator tank, where gas and emulsion
(mixture of water and gas) gets separated.The separated gas is then sent to Gas
Compression Plant (GCP) where the gas pressure is increased up to 50 kg/cm². The
pressurized gas is supplied to Captive Power Plant (CPP). Emulsion is separated by a 3 stage
heating process (at high temperature water and gas gets separated). The oil is sent to
Central Tank Farm (CTF) for storage and from there, it is sent to IOCL. The separated water
is sent to Water Injection Plant (WIP) for further usage.
9. ONGC GELEKY FIELD
ONGC Geleky field was discovered in 1968 and was put to trail production in
August, 1970. The commercial production started in August, 1974. The Geleky field is
located towards the southern fringe of Upper Assam near Naga Hills at a distance of 18 kms
from Nazira town and 34 kms from Sivsagar town. The field has been divided into 23 blocks
by faults. All the 23 blocks are oil or gas producers. In the Upper Assam Basin, the following
producing horizons have been identified (top to bottom):
Tipam Sand
Barail Sand
Kopili
Sylhet
Basement
In Geleky field, the main horizons are Tipam and Barail main sand. In addition, few wells are
producing within Barail coal-shale unit.
The geological age of the Barail main sand and Barail coal-shale is Oligocene and
that of Tipam is Miocene. The corresponding depth range of Barail main sand and Barail
coal-shale is about 3600-3900 meters. Tipam main sand, comprising of TS-3A, TS-4B, TS-5A,
TS-5B & TS-5C, is at an average total depth of about 2300-2900 meters. The average total
thickness of Barail main sand is about 70-80 meters, Barail coal-shale unit about 400-500
meters, and that of Tipam, TS-3A 20-30 meters, TS-4B 10-30 meters, TS-5A 10-40 meters &
TS-5B 10-20 meters, of oil bearing rock. The approximate area of this field is 28 sq. kms. The
initial oil in place for Geleky field is about 87.48 MMT.
10. MILESTONES OF THE GELEKY FIELD:-
YEAR
MILESTONES
1964 Presence of Barails and Tipams level was discovered
1968 The first wildcat well, G-001 was spotted in Tipams sand TS-5A
1970 Trial production of oil @100 tpd from the field started
1970-74 Drilling of 12 wells
1974 G-007, the first well put on production from Barail sands
1974 Regular production of oil started
1977 Commissioning of GGS-I
1977 Commissioning of GGS-II
1977 Commissioning of CTF
1974-78 Drilling of 60 wells
1979 Western extension of Geleky field was discovered through well
G-035
1982 Water Injection was first initiated through well G-036 in TS-5A
1982 Commissioning of WIP-I
1985 Commissioning of GGS-III
1982-86 Drilling of 30 wells
1986 Production rate increased to 930 m³/d
1990 Commissioning of CPP
1991 Commissioning of GCP-I
1998 Commissioning of WIP-II
1999 Commissioning of ETP
2000 Commissioning of GCP-II
2004 G-108 was the first well to be tested and produced from this
sand
2005 Current rate of oil production is 1600 tpd through 74 wells
2005 Water Injection is in progress in all the major reservoirs for
development schemes are available
11. GAS COMPRESSOR PLANT
There are three Gas Compression Plants namely GCP-I, GCP-II, GCP-III catering to
the gas compression requirement of Geleky Oil Field of Assam Asset.
GCP-I (GAS COMPRESSION PLANT NO. I), GELEKY
Gas Compression Plant No.I, Geleky (GCP-I) was commissioned on February 1991 to
meet gas-lift production requirements of the Geleky field. It has approval of the Director
General of Mines Safety vide permission no M11/OIL/31078 dated 19th July 1972.
Initially, it was started with 3 motors driven by KG Khosla Compressors with a
capacity of 90,000 SCMD each, along with a Cooling Tower, Cooling Water Recirculation
Pumps and Instrument Air Compressors and Dryer.
Gas Lift Mechanism requires injection of gas into the well at a high pressure
between 45 to 60 KSC and incorporation of gas lift valves into the tubing of the well.
Injected gas mixes with the well fluid which rises up from 600 metres below surface level to
reduce the density and lift it to the surface. To provide high pressure gas to wells, High
Pressure Compressors are used.
Gas separated from the well fluid in separated is called Rich Gas. Rich Gas collected
from GGS-5, Geleky and Rudrasagar is metered in the Gas metering station and finally
dispatched to GAIL at a pressure of 10 kg/cm². Rich gas from GGS-I separators is sent to the
MP Compressors section, where the pressure is boosted from 2.8 kg/cm² to 7.5 kg/cm². MP
section consists of 4 compressors of 2 stages double acting horizontal compressor driven by
motor. Natural gas is produced along with the crude oil, depending upon the nature of the
reservoir fluids & the pressure within it. This gas has two values of utility apart from acting
as fuel for heating of Bath Heaters & Heater Treaters in the Group Gathering Stations (GGS)
at Geleky Oil Field:-
As feedstock for value added products like LPG, NGL, ARN, chemical fertilizers etc. &
power generation.
As pressurizing agent to lift oil from the reservoir under lower pressures.
The Gas Compression Plant at GCP Geleky was commissioned to increase the
pressure energy of the gas separated out from the crude oil recovered from various wells at
GGS-I, II, III well fluids, so that the two utility functions as stated above can be achieved.
12. Process Description
Separators in GGS-I,GGS-II,GGS-III normallyruns in 3 different pressure modes:
@2.5 kg/cm²,
@6 kg/cm²
@16 kg/cm²
HP gas liberated from 16 kg separator is fed directly to the grid gas sales line going
to Lakwa. LP gas @2.5 kg/cm² from GGS-I to GGS-III is compressed to 6 kg/cm² by LP
Compressors ( 2 compressors at GGS-I of 15000 SCMD capacity & 3 at GGS-III of 30000
SCMD capacity) &sent to GGS-II.
Similarly gas from 6 kg separators also goes to GGS-II where they join in the
common gas manifold along with 6kg/cm² gas from GGS-I and from this common gas
manifold at GGS-II, gas at an average pressure of 4.5kg/cm² comes to GCP via 2 no. 12’’
buried lines. One line goes to MP suction Knock Out Drum (KOD) at GCP where liquid is
knocked off from the feed gas. Liquid is drained through LCV or manually & dispatched to
GGS-II via 2’’ line. LP gas from GGS-II is compressed to 7 kg/cm² by 2 LP Compressors of
16500 SCMDcapacities at GCP & joins MP suction KOD discharge line.
Dry gas from MP suction KOD is fed to MP Compressor A,B, C, D & GLC-1, 2, 3. MP
Compressors are 2 stage double acting reciprocating compressors of 165000 SCMD
capacity& can compress gas at 4.5 kg/cm² to 25 kg/cm². At present, discharge pressure of
the compressors is 12-16 kg/cm². Compressed gas from MP Compressor is dispatched to
Lakwa for sales to GAIL. In the MP compressor discharge line, a PCV is provided to maintain
suction pressure of MP & GLC by recycling the compressed gas to MP suction KOD. An
orifice type flow meter with remote flow transmitter is provided in the dispatch line to
measure the quantity of sales gas. Fuel Gas for GCP-II Caterpillar Engines is also supplied
from MP Compressor discharge KOD.
From the common suction header (in MP suction KOD discharge) gas is fed to GLC-
1,2,3. The 3 stage double acting reciprocating compressors of 90000 SCMD capacities can
compress suction gas at 4.5 kg/cm² to 83 kg/cm². However operating discharge pressure of
GLCs are maintained at around 50 kg/cm². Compressed gas is fed to the wells for gas lift
purpose.
GCP-1 was modified in stages to accommodate more Gas Lift Compressors of higher
capacity & subsequently two more motor driven KG Khosla Gas Lift Compressors of capacity
105000 SCMD were commissioned in August, 1995.
Another 12’’ line from GGS-II comes to suction KOD of GLC-4 & 5 at GCP-I. Dry gas
from KOD is fed to the suction of GLC-4 & 5. GLC-4 & 5 are 4 stage double acting
13. reciprocating compressors of 105000 SCMD capacity &compress suction gas @4.5 kg/cm² to
83 kg/cm². However as with GLC-1, 2, 3 operating discharge pressure is maintained at
around 50 kg/cm². Compressed gas from compressors join common discharge header & fed
to the wells for gas lift via GGS-II gas injection header & 48 gas injection headers.
GCP-II (GAS COMPRESSION PLANT NO.II), GELEKY
Commercial production of oil started in 1974. Since then Geleky oil field has been
considered as a prospective oil field of Eastern region. In due course of time as more & more
wells started losing their flow energy, high pressure gas injection system was introduced to
enhance secondary oil recovery from Geleky field & hence GAS COMPRESSOR PLANT was
born in the campus of CTF Geleky in February 1991.
To meet the requirement of lift gas GCP-II was commissioned in May, 2000 with 4
BPCL Compressors driven by Caterpillar Engines having capacity of 120000 SCMD each.
The reciprocating compressor 4HM/3 with horizontal balanced opposed crank is
designed to compress natural gas for gas lift operation. The cylinder and packings are
lubricated. The gas compression is carried out in 3 stages. Both first and second stages of
compression takes place separately in 1 no. DA cylinder whereas third stage compression is
performed in 2 nos. double acting cylinders. The crank mechanism has four opposed cranks
in order to completely balanced the inertial force. The compressor is driven by a Caterpillar
make G3606gas engine through a metaflex (double flexing disc) coupling type MR700. The
compressor rotation in anti-clockwise when viewed from driven end.
Gas from GGS-II comes to GCP-II via 18’’ pipeline. Hence fraction/condensate and other
liquids from natural gas are separated out at common suction Knock out Drum in GCP-II. The
gas is compressed to a pressure of 55-60 kg/cm² (present operating condition0 in three
stages by BPCL Compressors. Separators are provided at each stage for removal of liquid
particles present in the gas. The separators are equipped with level controller/dump valves
for auto drain off the condensate. Manual drain valves are also provided in parallel to auto
drain system. Dampeners are provided on each stage suction and discharge of cylinders to
limit the pressure pulsation. After discharge of each stage the gas passes through a forced
draft air cooled heat exchanger for cooling the gas to 50°C.
Process Description:
Natural gas is produced along with the crude oil, depending upon the nature of the
reservoir fluids & the pressure within it. This gas has two values of utility apart from acting
as fuel for heating of Bath Heaters & Heater Treaters in the Group Gathering Stations at
Geleky Oil Field :-
As feedstock for value added products like LPG, NGL, ARN, chemical
fertilizers etc. & power generation.
14. As pressurizing agent to lift oil from the reservoir under lower pressures.
The Gas Compression Plant at GCP Geleky was commissioned to increase the
pressure energy of the gas separated out from the crude oil recovered from various wells ay
GGS-I,GGS-II &GGS-III well fluids, so that the two utility functions as stated can be achieved.
In order to maintain a constant suction pressure, Pressure Control Valve is provided
at the outlet of suction KOD, which sends excess to flare in case of increase of pressure in
the suction header. Apart from this, a control valve is provided to bypass the gas from
compressor discharge to suction in case of drop in suction pressure. This control gets
actuated based on the signal from a pressure controller provided on Compressor suction
line. A common discharge KOD is provided for removal of liquid condensate, if any, from
discharge gas.
Gas from discharge KD at a pressure 55-60 kg/cm² is fed to gas lift network of GGS-
III and GCP-I,II. A constant gas lift network pressure is maintained for GCP-III with the help
of a PCV which allows the compressed gas to flow to gas lift network of GGS-I &II via GGS-II,
in case of discharge pressure exceeds pressure requirement of GGS-III.
Power Supply to GCP-II:
Sources of Power:
Captive Power Plant
Assam State Electricity Board
CPP at Geleky has 2 gas turbines of capacity 3 MWH each with an output of 11 KV. ASEB
supplies power at 33 KV at CPP end. Power from CPP is distributed through 4 feeders as
described below:
Feeder 1 Supplies power to MP Compressor- B, C, D & GLC-5
Feeder 2 Supplies power to GLC-1, 2, 3, 4, MP-A, Utility pumps & compressors &
lightning in GCP
Feeder 3 Supplies power to GGS-I, II & III, CTF. ASEB power is connected through
the feeder
Feeder 4 Supplies power to WIP
GCP- III (GAS COMPRESSION PLANT NO. III), GELEKY
GCP-III Plant was commissioned in March, 2009 with 4 Waukesha Gas Engine Driven
Cameron Compressors having capacity of 125000 SCMD each. Associated systems include
fuel gas to meet the fuel gas requirement of each compressor engine at 26000 SCMD. Flare
system containing flare KOD and water seal drum, raw water system providing service water
at 5 kg/cm² pressure to various consumers, cooling water system, instrument air system,
15. instrument air drying system, soft water system and closed blow down system. The whole
plant is controlled through state of the art PLC control system with Triple Modular
Redundancy (TMR).
WORK OF A MECHANICAL ENGINEER IN A PLANT
A competent Mechanical Engineering Technician – Plant Maintenance should be
able to do the following works:
Ability to plan and execute work in a safe and responsible manner.
Understand the nature of a problem and seek help through text, individuals or any
other method if deemed necessary.
Be able to collect data and present data in an easily understood way. Analyse the
data in order to remedy or predict situations which may arise.
Communicate basic information, ideas, problems and solutions with colleagues and
superiors.
Ability to compile technical reports and hand-over documentation.
Be comfortable working with tools, testing equipment and other related accessories
when working on plant machinery.
MAINTENANCE
Maintenance activities fall into 3 general categories:
Routine Maintenance: - Activities that are conducted while equipment and systems
are in service. These activities are predictable and can be scheduled and budgeted.
Generally, these are the activities scheduled on a time-based or meter based
schedule derived from preventive or predictive maintenance strategies. Some
examples are visual inspections, cleaning, functional tests, measurement of
operating quantities, lubrication, oil tests and governor maintenance.
Maintenance Testing: -Activities that involve using test equipment to assess
condition in an offline state. These activities are predictable and can be scheduled
and budgeted. They may be scheduled on a time or meter basis but may be planned
to coincide with scheduled equipment outages. Since these activities are predictable,
some offices consider them ‘’routine maintenance’’ or ‘’preventive maintenance’’.
Some examples are governor alignments and balanced and unbalanced gate testing.
Diagnostic Testing: - Activities that involve using test equipment to assess the
condition of equipment after unusual events, such as equipment
failure/repair/replacement or when equipment deterioration is suspected. These
activities are not predictable and cannot be scheduled because they are required
after a forced outage. Each office must budget for these events. Some examples are
governor troubleshooting, unit balancing, and vibration testing
16. Maintenance schedule
Maintenance inspections:-
A maintenance schedule includes these types of inspections:
Routine maintenance
Routine inspections
Three-month inspections
Annual inspections
Shorten the inspection intervals appropriately if the pumped fluid is abrasive or corrosive or
if the environment is classified as potentially explosive.
Routine maintenance
We should perform these tasks whenever performing routine maintenance:
Lubricate the bearings.
Inspect the seal.
Routine inspections
We should perform these tasks whenever checking the pump during routine inspections:
Check the level and condition of the oil through the sight glass on the bearing frame.
Check for unusual noise, vibration, and bearing temperatures.
Check the pump and piping for leaks.
Analyse the vibration.
Inspect the discharge pressure.
Inspect the temperature.
Check the seal chamber and stuffing box for leaks.
Ensure that there are no leaks from the mechanical seal.
Adjust or replace the packing in the stuffing box if you notice excessive
leaking.
Annual inspections
We should perform these inspections one time each year:
Check the pump capacity.
Check the pump pressure.
Check the pump power.
If the pump performance does not satisfy your process requirements, and the process
requirements have not changed, then perform these steps:
17. 1. Disassemble the pump.
2. Inspect it
3. Replace worn parts.
MAINTENANCE OF PUMPS:
Basically, there are two general classifications of pumps based on the method the pump
uses to impart motion and pressure to the fluid:
1. Dynamic Pumps,
2. Positive Displacement Pumps
Dynamic Pumps
Dynamic pumps continuously accelerate the fluid within the pump to a velocity
much higher than the velocity at the discharge. The subsequent decrease of the fluid
velocity at the discharge causes a corresponding increase in pressure. The most common
type of dynamic pump is the centrifugal pump.
Positive Displacement Pumps
Positive Displacement pumps enclose the fluid through the use of gears, pistons, or
other devices and push or ‘’displace’’ the fluid out through the discharge line. Displacement
pumps are divided into two groups-
Reciprocating (such as piston and diaphragm pumps)
Rotary (such as gear, screw and vane pumps)
RECIPROCATING COMPRESSORS
Reciprocating Air Compressors are manufactured in a variety of shapes, sizes and
capacities. Single-stage machines draw air from the atmosphere and discharge it into the
receiver or storage tank. Two-stage compressors bring the air up to intermediate pressure in
one cylinder and to final pressure in a second cylinder. Where two or more stages are
employed, the unit is defined as a multistage air compressor. Multistage Air Compressors
produce higher discharge pressures. Stationary air compressors are usually water-cooled,
with the exception of small units that are air-cooled. Portable units are also usually air-
cooled. Air-cooled compressors utilize finned cylinders to increase the radiating area.
Compressor drives include electric motors, steam reciprocating engines, steam turbines or
internal combustion engines. Drives may be direct connected, connected through reduction
gears, or belt connected. Operating and maintenance instructions for electric motors,
internal combustion engines, steam engines, and steam turbines drives are connected in
NAVFAC MO-205, Central Heating and Steam Electric Generating Plants.
18. High-Pressure Systems: Although high-pressure air compressors can compress air to
pressures of approximately 100000 pounds-force per square inch gauge (psig). Depending
upon the discharge pressure, the compressor will have from two to five stages of
compression, intercoolers between stages and an aftercooler. Smaller compressors may be
air-cooled or a combination of air and water-cooled while larger compressors are normally
water-cooled. Power for larger compressors is usually provided by electric motors, although
in some installations the compressors may be powered by diesel or steam engines. In
smaller compressor applications, gasoline engine drives may be provided. Power is normally
transmitted from the power source to the compressor through a direct drive or V-Belts.
Steam engines are usually integral with the compressor. Typical applications for high-
pressure air are:
Testing and operating catapults
Testing and launching missiles
Torpedo workshops
Wind tunnels
Ammunition depots
Fig: Air Compressor
19. SAFETY PRECAUTIONS
EXPLOSIVE HAZARDS: although compressed air at low or medium pressures is
dangerous if carelessly handled, the dangers associated with high-pressure systems are
of much greater consequence. Serious explosions, complete destruction of facilities,
and heavy loss of life have been attributed to unsafe practices involving high-pressure
compressed air systems. A serious potential danger exists in these systems whenever
high-pressure air is suddenly admitted into pockets, or dead ends, that are at or near
atmospheric pressure. The air temperature in the confined space is raised to the
ignition point of any flammable material that may be present. This auto ignition or
diesel action has been identified as the cause of several major disasters associated with
high-pressure air-systems. Such an explosion may set up shock waves that can travel
throughout the compressed air system and possibly cause explosions at remote points.
Under these conditions, even a small quantity of oil residue, a smear of grease, or a
small cotton thread may be sufficient to cause an explosion. Because of the serious
nature of these problems, it is extremely important that competent personnel
experienced in high- pressure systems, be employed for maintaining and operating
such equipment.
Preventive Measures: As a safeguard against explosions in high-pressure compressed
air-systems, a number of precautions should be taken.
a. Use of Slow-Opening valves: These valves are used in pocketed spaces as lines to
gauges and regulators to prevent a sudden pressure rise.
b. Elimination of Flame Arrestors: Flame arrestors, sometimes used to prevent the spread
of flame in pipelines. It should not be installed in high-pressure air systems as they may
create additional hazards.
c. Pipe Colour Coding: High-Pressure air lines are identified with a painted light gray band
and adjoining light green arrowhead pointing in the normal flow direction. These
markings are placed on high-pressure air lines at each point where piping enters or
emerges from a wall and immediately adjacent to all valves, regulators check valves,
strainers and other components.
d. Location of Equipment: High Pressure air storage and dryer cylinders are isolated from
other facilities as a precaution against damage that could result from rupture of the
cylinders.
e. System Tests: Before putting a high-pressure system into operation, the required
testing of NAVFAC DM-3.5. Compressed Air and Vacuum Systems must be
accomplished by competent personnel with an engineer responsible for safety.
20. PRESTART INSPECTION
Carefully inspect the compressor installation to ensure the following prestart
requirements are fulfilled
a) Verify all installation and repair work has been completed.
b) Ensure system has been cleaned and tested for leaks.
c) Ensure interstage and discharge safety valves are operating properly.
d) Ensure compressor and drive are lubricated in accordance with manufactures’ pump
or crank by hand to see that the oil is getting to all parts requiring lubrication.
STARTUP PROCEDURE FOR MOTOR-DRIVEN COMPRESSORS
(GCP-1):
Open all shutoff valves between compressor and receiver.
Make sure compressor is unloaded. Consult the manufacturer’s instructions for
procedure.
Turn on cooling water if provided. Thoroughly vent cylinder jackets and coolers if vents
are provided.
Turn compressor over by hand to see that all parts are free.
Start compressor motor. When up to speed, apply load if machine is running smoothly.
STANDARD OPERATING PROCEDUREOF STARTING AND
STOPPING Of GLC’s OF GCP-3
Startup procedure for GLC-10, 11, 12 & 14 of GCP-3
1. Check lube oil in Engine crank case and Compressor crank case, Menzel Oil pump
tank.
2. Soft water level in engine jacket water and auxiliary water tank.
3. Ensure suction, discharge valve & bypass/loading valve is in open condition.
4. Flare valves is closed.
5. All three inter-stage separators auto drain valves are lined up to intermediate blow
down tank/CBD tank as per their configuration.
6. Ensure air pressure is 8 kg/cm². Fuel gas and airline valves are in open condition.
7. Start compressor pre lube pump, lube oil pressure minimum 2.5 kg/cm².
8. Start Engine by pushing PB. Now Engine pre lube pneumatic pump will start.
9. After 180 second cranking will start by that time engine lube oil pressure will be
minimum 20 KPa.
10. Load engine to approx. 20% loading.
11. Close discharge to suction recycle valve slowly to avoid tripping on suction pressure
low.
21. 12. Now load by increasing RPM up to 1100 rpm or 79%.
13. Loading % and RPM may vary depending upon the engine condition.
14. Observe sound level and check for any leakages.
Shutdown procedure
1. Unload the compressor up to 20% & 800 RPM from the panel.
2. Stop engine from panel push button.
3. Open loader valve slowly.
Engine and compressor post lube pump will start automatically with the help of 110 V DC
supply for 60 seconds.
NORMAL OPERATION
While the systemis operating, perform the following tasks.
Watch for irregular compressor performance; excessive vibration; and overheating
of bearings, motors and packing.
Maintain proper lubricating oil levels.
Drain intercooler and aftercooler separators are necessary.
If automatic drainers are provided, check their operation.
Check temperatures and pressures of cooling water, compressed air, and lubricating
oil regularly.
SHUT DOWN
Unload the compressor before stopping the drive.
Drain separators, steamcylinders, and turbines.
Shut off cooling water supply if an automatic shutoff valve is not provided.
If the compressor might be subjected to freezing temperatures while shutdown,
thoroughly drain cylinder jackets, coolers and drain traps.
Extended Shutdown:
Any compressor taken out of service for an extended period will deteriorate rapidly
from rust and corrosion if not properly protected. Then take the following precautions:
Drain and refill the crankcase with preservative oil.
Operate the machine without pressure for no less than 15 minutes. This allows
thorough distribution of the oil and elimination of any crankcase condensate.
While the machine is running, spray a fog of preservative oil into the compressor
intake.
22. Remove piston rod packing and oil wiper rings from the rod or corrosion of the
piston rod may result. Coat the piston rod and oil wiper rings with grease and wrap
them in waterproof paper.
Tape or plug all openings to keep out moisture.
Relieve V-Belts of tension.
Drain the receiver and aftercooler.
Drain the aftercooler cooling water, if used.
CRANKGEAR LUBRICATION
LUBRICATION SYSTEM
The crank gear lubrication oil (force feed type), is supplied by a gear pump installed
on the shield at the nondrive end.
A special projection on the drive shaft is there for driving the lubricator. The lube oil
is sucked from the frame sump through a strainer by the gear pump and forced to the oil
cooler through a pipeline.
After leaving the cooler, the oil returns to the self-cleaning filter then it reaches the
oil distribution block. Oil is delivered from the distribution block to the crank gear
lubrication points by means of pipes.
Portion of excess oil leaving cooler is bypassed through bypass valve. Through the
drilled holes on the frame and on the shield, the lube oil passes to the two main bearings.
From the pump and main bearing, the oil through the line drilled in the crankshaft
arrives to the connecting rod bearing and from there to the connecting rod bush. Through
the holes drilled in crosshead pin and the oil reaches the crosshead shoes for lubrication.
A check valve which prevents the pump from loosingprime is placed on the pump
suction pump. Any how a hole closed by a plug is drilled on the suction line near the pump
for the pump priming. If due to leaking check valve, the suction line becomes emptied. The
line for pressure gauge and for pressure gauge and for pressure switch is tapped from the
oil circuit. Setting value of pressure switch is 1.5 kg/cm².
The crank gear lubrication before the compressor start-up can be done by an
electric motor driven auxiliary lube oil pump.
23. OIL PUMP
One gear pump circulates the oil.
The oil gear pump is designed for a capacity greater than is usually necessary;
therefore a hand adjusted safety valve with a set point of 6 kg/cm² ( 86psig) is built into the
pump.
Maintenance:-
The oil pump should be completely overhauled during the general overhaul of the
machine. After detaching the pump from the crank case dismount the various components.
Mark each component including the gear so that they can be reassembled in the correct
positions. Wash each component and check carefully.
OIL FILTER
After being cooled the oil passes through the filter. The filtering cartridges are of
wire gauge with opening of 35 to 40 mm.
The case is made of steel; the filter is installed separately on the foundation. The
filter is self-cleaning type. Just by turning the handle the filter element can be cleaned.
There is no interruption of the flow of the lube oil.
OIL CHECKING AND CHANGING
The lube oil should be frequently checked during machine operation to make sure
that impurities or dirt do not alter the oil characteristics.
Take special note of the oil appearance; turbidity indicates water leaks. Such water
leaks will almost certainly be found in the oil cooler. Such water leaks must be cured
without delay and the dirty oil replaced.
The pressure and temperature must be kept within limits previously stated.
After the first 1000 hours of running under load change the crank gear lube oil.
Then the oil change must be done every 4000 hours of running under load.
24. OIL SPECIFICATION
EPC is in no case responsible for any damage which should occur due to the use of lube oils
different from those specified below.
Oil need for complete change:
Compressor type Qty Lt.
4HM 130 to 160
LUBRICATION DATA
Oil pressure to bearings Inlet 2.5 to 3 kg/cm² g
(35 to 42 psig.)
Max. Oil filter Pressure drop 0.6 to 0.8 kg/cm² g
(8 to 12 psig.)
Oil temperature after cooler 40 to 50°C
(105 to 120 F)
MAINTENANCE
‘’ DO NOT USE GASOLINE, KEROSENE, OR OTHER LOW FLASHPOINT SOLVENTS.
A SERIOUS EXPLOSION MAY RESULT’’
1.LUBRICATION
Establish a lubrication schedule for air compressors. Normal oil levels must be
maintained at all times. Use only lubricants recommended by the manufacturer. Frequency
of oil changes is dependent upon severity of service and atmospheric dust and dirt. The time
for oil changes can best be determined by the physical condition of the oil. When changing
oil. Clean the inside of the crankcase by wiping with clean, lint-free rags. If it is not possible,
use a good grade of flushing oil to remove any settled particles.
OIL TYPE IOC SERVO SYSTEM 220
Viscosity (Centi stokes) at 40°C 220-230
Viscosity index (Min.) 90
Flash point ( Min.) °C 230
Pour point (Max.) °C -3
25. 2. PACKING
When replacing fibrous packing, thoroughly clean the stuffing box of old packing
and grease. Cover each piece of new packing with the recommended lubricant. Separate the
new rings at the split joint to place them over the shaft. Place one ring of packing at a time
in the stuffing box and tamp firmly in place. Stagger the joints of each ring so they will not
be in line. After the last ring is in place, assemble the gland and tighten the nuts evenly until
snug. After a few minutes, loosen the nuts and retighten them finger-tight.
3. CLEANING
Cylinder jackets of water-cooled compressorsshould be cleaned annually with
water. Dirt accumulations interfere with water circulation. Cleaning can be accomplished
using a small hose nozzle to play water into the jackets. On compressors fitted with
mechanical lubricators, cylinders may be cleaned with a non-flammable cleaning fluid.
4. VALVES
Replace all defective valve parts as required. When a valve disk or plate wears to
less than one-half its original thickness, it should be replaced. Valve seats may be resurfaced
by lapping or regrinding. On some valve designs it is necessary to check the lift after
resurfacing. If the lift is found to be more than that recommended by the manufacturer, the
bumper must be cut down an equal amount. Failure to do this results in more rapid valve
and spring wear. Carbon deposits should be removed and the valve assembly washed in
non-flammable cleaning fluid. Before replacing valves, make sure the valve seat and cover
plate gaskets are in good condition. If any defects are found, replace the gaskets. Make sure
the valve is returned to the same port from which it is removed. Carefully follow the
manufacturer’s instructions for valve removal and replacement.
5. PISTON RINGS
When replacing worn piston rings, the new rings must be tried in the cylinder for fit.
If the cylinder wall is badly scored or out of round, rebore the cylinder, or if cylinder liners
are fitted, replace them. If necessary to file for end clearance, take care to file the ends
parallel. Clean the ring grooves and remove any carbon deposits before installing the new
rings. To install new rings, place several metal strips not more than 0.032 inches thick
between the piston and rings. Slide the new rings over these strips until they are centered
over the grooves and then pull out the strips. Make sure the ring is free by rotating it in its
groove. Stragger the ring gaps of succeeding rings so they enter the bore easily. If this is not
available, wire the rings tightly so they enter the bore easily. Consult the manufacturer’s
instructions for carbon ring replacement.
Piston End Clearance: Always check piston end clearance after replacing pistons or
after adjustment or replacement of main, crankpin, wristpin, or crosshead bearings.
26. Consult the manufacturer’s instructions for proper clearances and method of
clearance adjustment. To measure piston end clearance, insert a length of 1/B-inch
diameter solder into the cylinder through a valve port and turn the compressor over
by hand so that the piston moves to the end of its stroke. Remove the compressed
solder and measure its thickness to determine the piston end clearance.
6. BEARINGS
Sleeve type main bearings are adjusted by removing or adding metal shims between
the cap and body of the bearings housing. The same number of slims should be added or
removed from each side of the bearing. Make sure caps are tightly secured so they
cannot work loose. Do not overtighten as this causes overheating of the bearing.
Horizontal Compressor Bearings: Many horizontal compressors have wedge
adjusting crosshead and crankpin bearings. Adjustment is made by tightening or
27. loosening the adjusting screws. Do not overtighten the bearings. A tight fit at the
crosshead guides and shoes.
Fig; Connecting rod with wedge Adjusting Bearings
Vertical Compressor Bearings: Vertical compressors are usually fitted with automotive
type crankpin bearings with babbitted inserts. These bearings are not adjustable and
must be replaced. When replacing bearing inserts or bushings, make sure all parts are
thoroughly clean and that the oil hole is aligned with the oil hole in the connecting rod.
Fig: Connecting Rod Assembly
28. 7. V-BELT DRIVES
Adjust tension or replace V-belts as required. When one or more belts in a set
require replacement, replace the entire set with matched belts. If this is not done, the new
unstretched belts, being shorter than the old belts, will carry most of the load and will be
subjected to undue strain. Removed belts that appear to be in a serviceable condition may
be kept for emergency use.
COOLING SYSTEM
1. Engine Jacket water closedcooling system
The cooling of engine jacket is done by circulation of soft water in closed loop. The
cooling water is closed in EJW section of the composite air cooled heat exchanger.
The water pump is driven by engine shaft through V-belts and is supplied by
CATERPILLAR.
A pressure switch PSLL 12 has been provided at outlet of engine. Jacket water which
causes shut down of the engine compressor unit when cooling water flow is low.
A self-cleaning 3-way temp, regular throttles the water flow by passing the radiator
at long as the water temperature in the piping out of the engine jacket is below 180 F (82°
C).
A twin tank has been provided as per the recommendation of engines
manufacturer, one of the tanks has a pressure cap suitable for 7PSI pressure and other tank
is provided with a float valve for auto filling of the tank.
Flexible hoses have been provided at engine water inlet and outlet connections to
isolate the piping frame vibration of the engine.
2. Engine Lube Oil and compressor cooling system
Cooling of C.W. for compressor cylinders and lube oil, engine oil and engine
aftercooler is done by circulation of soft water in closed loop.
Water is circulated by an extra capacity centrifugal pump, supplied by engine
manufacturer, driven by engine shaft through V-belts.
The piping conveying water from auxiliary water section of the air cooled heat
exchanger branches off from pump discharge header.
One line goes to the engine AC/DC circuit and other goes to compressor cylinders &
oil cooler.
29. An auxiliary water surge tank has been provided to take care of the unavoidable
pressure drop which may occur in the systemand to accommodate the increase in the
volume of water at heating stage. The auxiliary water tank is equipped with a Floate type
valve for auto filling of the tank.
Filling of the cooling water circuit
It is recommended to fill at first the engine C.W. circuit and subsequently the
compressor cooling circuit. Open all the bleeding valves provided in the circuits.
Remove the drain plug provided at the lowest point of each circuit and connect the
water hose.
The water flows in the circuit and tends to force the air out through bleed valves
and vent connection provided in the water tank.
The system should be filled slowly to avoid air pockets formation in the bends of
the lines as air pockets hinder water circulation and prevent proper heat transmission.
Emptying the cooling water circuits
To drain the cooling water from the gas engine compressor circuits open the bleeds
valves and drain plugs in the circuits.
When the compressors is provided with water cooled type packing drain water
thoroughly from the packings, disconnect the filling on the water outlet pipe from the
cylinder and pass the compressed air towards the cylinder until the water comes out.
Air cooled heat exchanger for gas and water cooling
The radiator consists of five sections, three sections are of gas cooling i.e. for
internal cooling and after cooling of the gas and other sections are for water cooling, one for
engine jacket water and other for auxiliary water.
The radiator fans are driven by engine shaft through 4 nos. Match marked SPC 2650
VEE-Belts
30. AUXILIARY EQUIPMENT
INTAKE FILTERS
Air Filters are provided on air compressor intakes to prevent atmospheric dust from
entering the Compressor and causing scoring and excessive wear. There are two types of air
filters:
Dry type Filters
Oil-Wetted Filters
Generally, dry type filters are more efficient than oil-wetted types in trapping and removing
very fine, solid particles from the incoming air. However, dry type filters must be cleaned
and replaced more often than oil-wetted types. Oil-wetted types are often used where
there are heavy dust concentrations present in the atmosphere.
Dry Type Filter
Dry filters employ many materials for the filter media. Paper, polyester felt, and fine wire
mesh are a few examples. The filter media can be folded, wrapped, and layered in many
configurations to achieve the desired efficiency. Although the dry filter is more efficient
than the wetted type filter, the pores in the dry filter media become clogged and result in a
pressure drop across the filter. Dry type filters cannot be used successfully where intake air
contains moisture or vapours in amounts that would cause disintegration of the filtering
media. The main advantage of the dry type filter is its high efficiency and ease of
maintenance.
Fig: a worker cleaning Dry Type Air Filter
31. Oil-Wetted Type Filter
Oil-Wetted filters have filter elements that are coated with a filmof oil. The oil film catches
airborne particulates before they reach the actual filter element media. Wetted type filters
are of two designs, Oil-wetted and Oil-bath filters.
INSPECTION
Air filter inspections are to be performed when any of the following conditions exist:
a) Prescribed time interval on the maintenance schedule has elapsed.
b) Pressure drop across the filter element indicates a maintenance requirement.
c) One-fourth inch of sludge has built up in the oil sump of the oil-bath type filter.
MAINTENANCE
Dry Type Filter: Service the filter assembly as follows:
Shut down compressor and tag controls.
Remove top of filter assembly.
Remove filter element and clean as prescribed by manufacturer or replace.
Reassemble filter element and top to filter assembly.
Remove tag from controls.
Oil-Wetted Type Filter: Clean the filter assembly as follows:
Shut down compressor and tag controls.
Remove the top and filter element from filter assembly.
Wash filter element with approved solvent or detergent and water solution.
Dry filter element thoroughly.
Apply fresh oil by spray or dip and let excess oil drain. Use oil type suggested by
manufacturer.
Clean filter body.
Reinstall filter element and top to filter assembly.
Remove tag from controls.
Oil-Bath Filter: Clean the filter assembly as follows:
Shut down compressor and tag controls.
Remove filter assembly from compressor.
Wash filter element with approved solvent or detergent and water solution.
Dry filter element thoroughly.
Clean and dry filter oil sump.
Add oil to oil sump to indicated level.
32. Reinstall filter element and top on filter assembly.
Reinstall filter assembly on compressor.
Remove tag from controls.
SAFETY
Whenever work is to be accomplished on gas compressor plants, there is always the
possibility of a hazardous situation occurring, which could result in serious injury to or death
of personnel. Performance without injury is a sign of conscientious workmanship and
planned supervision. Therefore, safety is a primary consideration when operating,
inspecting, or maintaining any of the gas compressor plants.
The following safety rules should be followed:
All personnel should be trained and qualified in Cardio-Pulmonary Resuscitation
(CPR).
All personnel should wear safety shoes.
All personnel should wear clothing appropriate to the job being performed.
Eliminate loose clothing, which can get caught in machinery.
Wear hardhats when required.
All personnel should wear eye and ear protection prescribed for the task being
performed.
Report all injuries even if they seem to be minor.
DO NOT WORK ALONE. At least one other person should be on hand to provide
assistance, if needed.
Always use the correct tool for the job.
Prevent skin ruptures and sensory injuries when working with compressed gas. Close
isolation valves before working on lines or fittings.
Follow lockout and tagout procedures prescribedfor the plant.
Current and accurate drawings of various mechanical systems are essential for
operational safety of the plant.
34. During this winter Training, after completing my training at GAS COMPRESSION PLANT
(GCP), Geleky, I visited the Diesel Shop in Central Workshop, Sivsagar.
CENTRAL WORKSHOP, SIVSAGAR:
Central workshop located at Sivsagar .supports the requirements of
oil field activities of the remote North East region.
The activities of the Central Workshop,Sivsagar are as follows-
1. Overhauling of drilling rig equipments/works over rig
equipments.
2. Draw works/mud pump/compressor/rotary table/swivel/crown
block/ travelling block / hook block, etc. are used in drilling.
3. Overhauling of surface equipmente.g. Diesel engines, water
injection pumps etc.
4. Overhauling of electric machinery of drilling rig / work over rig
and surface equipments.
5. Allied repairs (cleaning and repairing of radiation / heat
exchangers / coolers etc.)
6. Tubular inspection and NDT.
7. Repairs and calibration of instrumentation, etc.
35. The central workshop is basically divided into five major shops:
Heavy equipment repair shop:
This shop repair heavy equipments like draw works, mud pump,
rotary table, swivel, crown block, travelling block, hook block, testing
of BOP etc.
Compressor and torque converter (T.C) shop:
Here the repair and maintenance of various compressors takes place.
TC shops also includes repair of Allison Transmission System.
Machine Shop:
Machine shop is equipped with lathe machine, drilling machines,
align machines, boring machines, etc.
Diesel Engine shop:
Diesel engines are repaired in this shop. The shop includes a fuel
injection lab. This shop also carries out trouble shooting and
periodical inspection of diesel engines.
Tubular repairing shop:
In this shop several lathe machine are used to repair pipes used in
drilling and well logging. The pipe is repaired by cutting thread in the
pipe or cutting off the waste portion of the pipe.
36. DIESEL ENGINE SHOPS
The diesel engine is an internal combustion engine in which ignition
of the fuel that has been injected into the combustion chamber is
initiated by the high temperature which a gas achieves when
highlycompressed .It is named after its inventor Rudolf Diesel.
Fig. Cut model of Diesel Engine
37. Some of the important engine components are discussed below:
1. Cylinder Block: A cylinder block is the main supporting
structure for the various components.
2. Cylinder Head: The cylinder head is mounted on the cylinder
block. A casting containing valves and injectors fitted on the
top of the block forming the upper part of the combustion
chamber.
3. Cylinder Liners: Alloy cast iron open ended cylinders pressed
into the block forming the walls of the combustion chamber.
These cylinders are replaceable.
4. Aftercooler: Located in the cooling system to cool the intake
air allowing denser intake air for more efficient combustion.
5. Bearings: Replaceable, steel backed inserts located on
crankshaft journals.
6. Camshaft: Shaft located in the block, used to actuate valves
and injectors through push rods. The camshaft and its
associated parts control the opening and closing of the two
valves. The associated parts are push rod, rocker arms, valve
spring and tappets. This shaft also provides the drive to the
ignition system. The camshaft is driven by the crankshaft
through timing gears.
7. Camshaft Followers: Sits on the cam lobe (one per lobe)
transmitting lobe profile to push tubes.
8. Crankshaft: Steel forging used to convert reciprocating
motion of piston into rotation motion at the flywheel.
9. Filters: Cartridges containing special paper, located in the
main systems (air, cooling, lubrication and fuel) to remove
solid material which could be detrimental to engine
operation.
38. 10.Flywheel: A large alloy cast iron disc attached to the
crankshaft used to store the energy produced during power
stroke, also provides a main power take off point.
11.Fuel Pump: Drawing from tank, supplies fuel at low pressure
to injectors.
12.Gear Housing: Aluminium or cast iron housing located
generally, at the front of the engine covering the gears
transmitting power to the engine driven accessories.
13.Injector: A device located in the cylinder head, designed to
meter the quantity of fuel, and then supply that fuel under
high pressure into the cylinder at appropriate time.
14.Lubricating Oil Pan: Circulates lubricating oil under pressure
to the bearings and moving parts through drillings in the
blocks, heads and crankshaft.
15.Oil Pan: Container attached to the base of the cylinder block,
used to hold the lubricating oil.
16.Piston: An aluminium alloy cylindrical in shape which is
designed to slide inside the cylinder liner. It forms the first
link in transmitting the gas forces to the output shaft.
17.Piston Ring: A ring mounted in special grooves in the piston
circumference.
18.Starter Motor: An electrical, pneumatic or hydraulic machine
which is used to accelerate an engine from a stationary
situation to a firing speed.
19.Connecting Rods: It interconnects the piston and the
crankshaft and transmits the gas forces from the piston to the
crankshaft.
20.Turbocharger: Device which utilizes waste heat in the
exhaust gases to provide additional air to the engine resulting
in additional power output.
39. 21.Valve (intake and exhaust): It is located in cylinder head,
mushroom shaped, used to allow exhaust or exhaust gases to
enter or leave combustion chamber at appropriate time in
cycle.
22.Inlet Manifold: The pipe which connects the intake system to
the inlet valve of the engine and through which air is drawn
into cylinder is called the inlet manifold.
23.Exhaust Manifold: The pipe which connects the exhaust
system to the exhaust valve of the engine and through which
the products of combustion escape into the atmosphere is
called exhaust manifold.
24. Vibration Damper: It is a very important unit mounted on
the front of the crankshaft, used to damp down torsional
vibrations caused by the firing impulses in each cylinder.
25.Water Pump: Circulates water through the engine block/
head to remove heat and cool the water which would
otherwise cause engine to seize.
The working of a Diesel Engine is governed by systems namely-
Air system
Cooling system
Lubrication system
Fuel system
AIR SYSTEM
The functions of air system are-
1.To supply air for complete combustion of fuel.
2.To take exhaust gases out of engine.
So, it is divided into two parts
o Air intake system
o Exhaust system
41. AIR INTAKE SYSTEM
The components of air intake system are-
1. Air cleaner-element/housing:Dry type air filters with tough
paper element are used in diesel engines. It filters the air passing
in the combustion chamber and prevents the entry of dust and
moisture. These filters are replaceable.
2. Hump hose-Hump hose leads the air from the cleaner to the
turbocharger or intake manifold. It connects the housing and
suction pipe.
3. Suction pipe and vacuum indicator-The suction pipe is always
under suction and is transfers clean air to turbocharger or intake
manifold. Vacuum indicator is mounted on it and even a hose
can be connected for remote vacuum indicator.
4. Turbocharger-Aturbocharger is a
forced induction device used to allow
more power to be produced for an engine
of a given size. The turbocharger is
driven by exhaust gases and its speed
ranges from 80,000 RPM to 100,000
RPM. Itconsists of turbine casing and
turbine wheel, impeller, casing and
bearing housing.Both the turbine and the
compressor impeller are mounted on the
same shaft. The exhaust gases are
directed on the turbine wheel. As the
turbine wheel rotates the compressor impeller rotates
simultaneously and the clean air from the air cleaner is drawn
and pressurized before it enters intake manifold.
Fig:Turbocharger
42. Advantages of turbocharger:
More air intake so more fuel is burned. Hence more power is
obtained.
Utilized energy of exhausted gases hence more efficient.
More air at lower speed causes better fuel consumption.
5. Air crossover connection-It leads the pressurized air from
turbocharger to intake manifold. It has various configurations
and is sealed with clamps and gaskets.
6. Aftercooler: Aftercooler is fitted in housing or intake manifold
and it consist of a bundle of tubes to circulate engine coolant.
The pressurized hot air from the turbocharger enters into the air
cooler where the heat from the air is absorbed by the coolant.
The temperature of air falls from 300 F to 218 F. The coolant
flows inside the tubes and air flows through the fins.
7. Intake manifold:It leads the air to the intake port of the
cylinder heads. It is under suction in naturally aspirated engines
and pressurized in turbocharged engines. It distributes the air
evenly to all the intake ports.
8. Intake valves:Two intake valves are provided per cylinder for
better scavenging. The cross head opens both the valves
simultaneously.
9. Combustion chamber: The combustion chamber consists of
cylinder liner ,piston rings ,piston top and combustion face of
cylinder head. Proper sealing is done to prevent the leakage of
hot gases.
43. EXHAUST SYSTEM
The components of exhaust system are-
1. Exhaust valves-These are outlets to expel the burned gases
from the engine. These valves reach a temperature of
1400F.These valves are made of high grade metal for maximum
strength without stress.These valves must open and close at the
right instant.
2. Exhaust manifold: Pipe through which exhaust gases comes
out.
3. Exhaust piping-The diameter of the piping should be such as to
limit the back pressure. The number of bends is minimum and
there must not be sharp bends.
4. Exhaust system support-These prevent load on the exhaust
manifold and on turbo charger. It maintains flexibility to absorb
shocks and vibrations. It also provide support to piping and
silencer to prevent load on the engine.
5. Silencers/mufflers-The role of silencer is to reduce noise
without increasing back pressure. It has industrial, residential
,critical applications.
44. COOLING SYSTEM:
A cooling system is a heat regulating system, where helps in
removing the excess heat and maintain the normal operating
temperatures, ensuring best fuel economy and peak performance.In
diesel engine one third heat is transferred to the cooling system.
Basic functions of the cooling system are
1. Circulation of coolant throughout the system.
2. Absorption of heat from liners or cylinder head.
3. Controls coolants temperature at desired range.
3. Dissipation of absorbed heat to the atmosphere.
Component of cooling system:
1. Water Pump-It is a centrifugal pump to circulate coolant.
2. Oil cooler-The basic function of Oil cooler is to remove excess
heat from oil.They are of different shapes configurations and
sizes.
3. Temperature regulator or Thermostat
4. Radiator -The basic function of a radiator is water storage and
excess heat dissipation.It has 3 parts namely head transfer
core,inlet tank,outlet tank.
5. Heat exchanger-It is used in place of a radiator. It consist of a
bundle of round or flat tubes in a housing.Raw water flows
through the tubes and engine coolant around the tubes and raw
water absorbs heat from the engine coolant.
6. Pressure cap
45. 7. Coolant system hoses
8. Flex master couplings
9. Radiator fan-It assists the air flow between radiator tubes and
engine.The air pushed or pulled by fan carries heat away from
coolant in radiator tubes.The fans are of 2 types namely sucker
fan and blower fan.
10.Fan shrouds-It improves the cooling efficiency and provides
uniform distribution of air over radiator core.It prevents the
recirculation of air around the fan blades and ensures that
vibrations are limited.
11.Belt and pulleys-V or poly V belts are used to drive water
pump or fan.It transfers rotating moment of crankshaft directly
or through auxiliary drive position.
46. LUBRICATION SYSTEM
A Lubricating oil lubricates, cools,cleans,prevents corrosion,seals
combustion chamber from crankcase and dampens the shocks.
The components of lubricating system are-
1. Oil pan-It stores the oil required by the engine.
2. Oil pump-It pulls oil from oil pan through screen assembly and
suction tube.
3. Pressure regulator –It is located in the pump/filter head and it
consists of spring loaded pressure release valve.It dumps back
oil to the oil pan when pressure exceed 70psi.
4. Lubricating oil filter-It is paper element type.
5. Filter head
6. Super bypass filter
7. Oil coolers
8. Piston cooling nozzles
9. Pressure gauge
10. Dip stick
11. Lubricating oil
47. FUEL SYSTEM
The basic objective of fuel system are-
1. To control the quantity of fuel to each cylinder.
2. To ensure that the fuel is delivered at correct time.
3. To deliver the fuel in correct condition.
4. To govern the engine speed.
The components of fuel system are-
1. Fuel tank- it is used as storage for engine requirement and
returns the fuel. It has baffles,vent and drain valve.
2. Water separator- in the water separator the fuel is given
circularmotion and the water is collected at the bottom with
centrifugal force. The water is drained periodically
3. Fuel filter-It removes foreign material from fuel before entering
the fuel pump. A paper element forms the barrier for flow in and
flow out of the fuel.
4. Fuel pump-it this pump vacuum is created and thus fuel is
sucked from the filter. The pressure at the outlet of gear pump is
4-5 times the final requirement.
5. Governor- It controls the supply of fuel with the change of
speed and load.
6. Fuel manifold –supply of fuel pump to the injector.
7. Shut down valve-It is an electrically operated valve (solenoid
valve). It is mounted on fuel delivery port. Fuel goes to injector
through shutdown valve
49. PT PUMP (Pressure Timing) PUMP:
FIG :PT PUMP (Pressure Timing)
Function of PT pump:
The function of the PT Pump is to suck fuel from the tank through the
filter and to the pump. Transfer fuel into a common including no load
and fuel load. Allow the operator to control speed via the throttle.
Control exhaust emission and to switch fuel on and off when required.
The pump transfers diesel in a common fuel line feeding to each
injector. Each injector is timed from the camshaft. Therefore the
pump does not need to be timed and it simply supplies enough fuel
under pressure to be continuously available for each injector. Any
excess fuel returns to tank from both the pump and injectors.
How does PT pump work?
As the operator accelerates fuel is sucked from the tank into the filter
and water separator and then the pump from the pressure created by
gears within the pump. Fuel enters the pump through another filter
screen located at the top of the pump. The filter helps to catch any dirt
that has accidently bypassed the primary filter. Fuel then flows into
the governor sleeve. The governor plungers position allows fuel
through various plunger ports. The AFC plunger position is
determined by the pressure coming from the turbocharger. At start up
little boost pressure will come from the turbocharger and therefore the
50. AFC will reduce fuel flow. Therefore AFC acts as a restriction device
and work s in harmony with air intake from the engine manifold. The
position of the AFC plunger allows the volume of throttle fuel to flow
into AFC from the AFC through an electric solenoid and onto the
common fuel rail. The fuel rail then feeds the injectors. Some of them
return back to the tank and helps cool down the pump and injectors as
well as prevent excessive build-up of pressure within the pump. The
horsepower can be adjusted by changing the maximum fuel delivery
pressure from the gear pump. Buttons of various sizes can be installed
within the pump assembly to change maximum fuel delivery pressure.
FUEL PUMP
FIG: Fuel pump
An injection pump is the device that pumps fuel into the cylinder of a
diesel engine. Traditionally, the pump is driven indirectly from the
crankshaft by gears, chains or toothed belt that also drives the
camshaft. It rotates at half crankshaft speed in a conventional four
stroke engine. It timing is such that the fuel is injected only very
slightly before top dead centre of that cylinder’s compression stroke.
It is also common for the pump belt on gasoline engines to be driven
directly from the camshaft. In some systems injection pressures can
be as high as 200 MPa.
51. ONGC DRILLING RIG
A drilling rig is a machine that creates holes in the earth sub-surface.
Drilling rigs can be massive structures housing equipment used to
drill water wells, oil wells, or natural gas extraction wells, or they can
be small enough to be moved manually by one person and are called
augers. Drilling rigs can sample sub-surface mineral deposits, test
rock, soil and groundwater physical properties, and also can be used
to install sub-surface fabrications, such as underground utilities,
instrumentation, tunnels or wells. Drilling rigs can be mobile
equipment mounted on trucks, tracks or trailers, or more permanent
land or marine-based structures (such as oil platforms, commonly
called 'offshore oil rigs' even if they don't contain a drilling rig). The
term "rig" therefore generally refers to the complex of equipment that
is used to penetrate the surface of the Earth's crust.
Fig: Drilling rig.
53. Measuring instrument used in workshop
1. Magnetic stand: It is used to measure clearance.
2. Micrometer: It is used to measure inside and outside diameter of
cylinder or spherical object. It has least count 0.01mm. There are
two types of micrometer. These are internal micrometer and
outside micrometer. It gives accurate measurement.
3. VernierCaliper: It is a measuring instrument that measures
internal dimensions, outside dimensions and depth. It can measure
to an accuracy of one thousandth of an inch and one hundredth of a
millimeter. It has least count 0.02mm.
4. Caliper: There are two types of callipers. These are inside and
outside calliper which are used to measure inside and outside dia. It
has least count 0.02mm.
5. Bore Gauge: It is used to measure bore’s size by transferring the
internal dimension to a remote measuring tool or it is used to
measure interior size of a hole, cylinder or pipe.
6. Clearance Gauge or Filler Gauge: It is used to measure gap
width.
Example:To measure gap between roller cage and outer ends of
bearings.
7. Vernier Depth Gauge: It has least count 0.02mm. It is used to
measure depth.
54. CONCLUSION
It was a knowledgeable experience to undergo training in Oil
and Natural Gas Corporation Limited (ONGC). I got a chance to see
and learn about several things related to the maintenance of engines
and machines. I was provided with various information and technical
knowledge about different production installation.
Moreover, I was provided with a very conducive and
interactive environment by my mentor to let me learn as much as I
can. It has been very fruitful to me that I learned the practical
aspects of the subjects of Mechanical Engineering. The whole
journey has been very educative as I could practically see what was
taught to us in our theories.
