Report on ONGC HAZIRA plant and project description of mechanical pumps used in ONGC plant

1. 1
VOCATIONAL TRAINING& PROJECT REPORT
MAINTENANCE OF CENTRIFUGAL PUMP IN
OIL AND NATURAL GAS CORPORATION LIMITED
HAZIRA, SURAT, GUJARAT
Training Period - 11/5/2017 to 9/6/2017
SUBMITTED BY. SUBMITTED TO.
CHANDRA KISHOR AZAD MR. ARUN DUTTA
KDM TRAINING CENTER
JAYKUMAR H. LAD ONGC, HAZIRA PLANT
NIKHIL CHAVDA
SHUBHAM JAIN
ANAND PADHIYAR
PRANAV BAGHERIA

2. 2
ACKNOWLEDGEMENT
Industrial Training is an integral part of engineering curriculum providing
engineers with first hand and practical aspects of their studies. It gives them the
knowledge about the work and circumstances existing in the company. The
preparation of this report would not have been possible without the valuable
contribution of the ONGC family comprising of several experienced engineers
in their respective field of work. It gives me great pleasure in completing my
training at Gas Processing Plant of ONGC at Hazira and submitting the training
report for the same.
I express my deepest gratitude to Mr. ARUN DUTTA for giving us the
permission for orientation in operational area of plant. I am also thankful to Mr.
MANISH BHOWMIK who supported us constantly and channelize our work
toward more positive manner.
Our sincere thanks to Mr. MANISH BHOWMIK Dy SE (M), for continuously
guiding throughout various aspect, functioning, and processes of the plant and
their effective coordination and allotting us the appropriate schedule to
undertake the training.
A major contribution of this work would definitely be my parents who have
constantly supported me for my training in here and my friends who have
always been there as a pillar of strength.
And at last but not least we are also thankful to all the staff members of plant for
their kind cooperation and valuable guidance throughout the process of work.

3. 3
PREFACE
In any organization success or failure of the company depend upon 4 M’s i.e.
Materials, Men, Machine and Method. Today is the age of competition and an
organization cannot survive without satisfaction of its customers. Quality of
material is to be maintained in order to stand in the competitive market.
To be a perfect engineer one must be familiar with individual experience in
industrial environment. He must be aware of basic industrial problems and their
remedies.
While undergoing this type of industrial training at ONGC, Hazira, Surat
(Gujarat). I learned a lot of practical aspect. My theoretical knowledge was
exposed here practically. In this report I have tried to summarize what I have
learned in the ONGC plant. For preparing this report I visited the plant, referred
to the process and cleared related doubts to the responsible personal & inferred
to manuals and process reports.
This study has been primarily undertaken by me with a view to evaluate proper
working process in the organization. Born as the modest corporate house in
1956 as a commission ONGC has grown today into a full fledges integrated
upstream petroleum company with in house service capabilities and
infrastructure in the entire range of oil and gas exploration and production
activities achieving excellence over the years on the path of further growth.

4. 4
INDEX
 ACKNOWLEDGEMENT 2
 PREFACE 3
 HGPC : An Introduction 5
 Plant Overview 9
 Mechanically Important Equipment
In Plant 13
 Centrifugal pump 15
 Procedure for starting and stopping
the centrifugal pump 21
 Types of Maintenance 26
 Preventive Maintenance 27
 Breakdown Maintenance 34

5. 5
HGPC : AN INTRODUCTION
Oil and Natural Gas Corporation (ONGC) is India’s biggest public sector
company. The mission of this company is to stimulate, continue and
accelerate exploratory efforts to develop and maximize the contribution of
hydrocarbons to the economy of the country. The discovery of Bombay High
was an important event in ONGC’s success as a result many oil fields were
discovered in the western offshore. Out of them South Basein proved to be
phenomenal having reserves of approximately 200 billion cubic meters of
sour gas. To sweeten this sour gas (make it sulphur free) and make it suitable
for industrial use Hazira Project materialized.
Hence a gas terminal was constructed in 1985 to receive the sweet gas.
Initially the gas received at this terminal was fed to KRIBHCO. Thus, entire
Hazira area saw the beginning of gas based industrial era. With increased
demand in gas and its availability in the south Basein ONGC, Hazira
improved its production capacity and infrastructure.
Hazira Gas Processing Complex (HGPC)

6. 6
Process Flow Diagram

7. 7
The gas processing plant of ONGC at Hazira processes gas coming from the
Vasai, south Basein, Heera, Panna, Mukta and other fields of the Bombay
offshore region, established in 1985, it is the largest gas processing plant of its
type in India with a production capacity of about 45 Mm3
of gas/day and
8000m3
of condensate/day. Spread over 705 hectares, with a boundary covering
11km, it has about 770 employees working for it presently and had an initial
capital expenditure to the tune of Rs.1300 crores.
Initially it was set up in 1985 to receive sweet gas from Bombay high but
with time it was seen that there were concentrations of sour gas that with the
incoming flow and it was then completely turned up into a sour gas plant.
The gas terminal was constructed in 1985 to receive sweet gas from Bombay
High through 217 km 36” & 42” submarine pipes from south basin to
Umbrhat and then 14 km pipeline on land till the gas terminal. The output of
the plant sustains the HVJ pipeline, which is a gas pipeline of more than 3000
km in length and covers many states like Gujarat, M.P, Rajasthan, Haryana,
U.P, and Delhi. The plant also supports various fertilizer plants and power
plants which depend on the gas coming out of the Hazira plant.

8. 8
Products:
Main products of HGPC are as following:
 Sweet Natural gas
 Liquified petroleum Gas
 Naptha
 Superior Kerosene Oil
 Aviation Turbine Fuel
 High Speed Diesel
 Sulphur
The input lines are feed to the GTU, which separates the gas from any
condensates. The gas then goes to GSU, where it is sweetened i.e. freed from
H2S .The condensate goes to CFU. From GSU, the gas goes to GDU, where
the moisture content from the gas is removed. The H2S gas which is ripped in
GSU is sent to SRU, where sulphur is recovered in elemental form. After
GDU, the gas goes to DPD unit and then to consumers. The condensate from
CFU goes to KRU plant and any LPG produced is sent to CWU for recovery
by removing H2S. The process is represented in the flow chart as shown
above.

9. 9
PLANT OVERVIEW
1). Gas Terminal
A specially constructed onshore terminal is set up to receive the sour gas and
associated condensate from offshore (ONGC & JV Fields).The first phase of
this terminal was established in september,1985 and the supply of the gas
from bombay High to KRIBHCO's fertilizer plant at Hazira started. This
terminal also monitors metering of gas supply to other local consumers.
The sour gas and condensate received from Offshore in a multiphase flow are
separated by gravity into two streams, viz. and liquid as a first step. For this,
the fluids coming from offshore trunk pipelines are routed through a set of
Pressure Reduction Control system (normally set at 70kg/cm2)Then through
the cyclone separators/filters the fluids are distributed to Slug Catchers for
separation of gas and liquid. Slug Catchers are nothing but set of parallel pipe
fingers of 48 inch diameter and approximately 500 meters in length. These
pipe fingers are mounted at a slope of 1:500; thus forming separation and
collection zone. The sour gas separated is taken out from top riser pipes to
Gas Sweetening Units and the sour liquid thus collected is routed to
Condensate Fractionation Units.
2). Gas Sweetening Units
The main objective of the Gas Sweetening Unit is to remove H2S from Sour
Gas for supply of sweet gas to consumers. Apart from the local consumers,
the gas after processing is supplied to Hazira-Bijaipur- Jagdishpur Pipeline of
GAIL for onward distribution to more than 70 industries along the HBJ
pipeline.
The state of art MDEA process licensed by SNEA(P),France is being adopted
for Gas Sweetening. In the process sour gas at 20-33 C and 77- 54 kg/cm abs
pressure comes in counter current contact with lean MDEA in the absorber.
The Sweet Gas leaves the top of the absorber with 4 ppm (max) H2S and
forms feed for the Gas Dehydration Unit. Rich MDEA solution from bottom
of the absorber is then regenerated in the regenerator. Lean Amine from the
bottom of the regenerator after flashing and cooling is then re-circulated back
to the top of the absorber. Acid gas coming from top of the regenerator forms
feed for the Sulphur Recovery Unit.

10. 10
3). Gas Dehydration units
This unit aims at removal of moisture from the Sweet Gas. Tri Ethylene
Glycol (TEG) process is adopted for gas dehydration. The Sweet Gas from
the Gas Sweetening Unit enters the absorber at 74.9-51.9 kg/cm2(absolute)
and 38°C wherein it comes in counter current contact with lean TEG
solution. The Dry gas from top of the absorber forms the Dew Point
Depression Unit. Rich TEG solution from the bottom of the absorber is
regenerated in the regenerator column. Lean TEG from the bottom of the
regenerator is then re-circulated back to the top of absorber.
4). Dew Point Depression Units
The Sweet and dehydrated gas treated in this unit to lower the hydrocarbon
dew point of the gas well below the minimum temperature, which the gas
may attain in the HBJ pipeline. The feed gas is first cooled in the gas/gas
exchanger and is further cooled to +5°C in a gas chiller by evaporating
refrigerant propane. The hydrocarbon condensate after the separation is
pumped to the LPG plant or the Slug Catcher Condensate Header. Dew Point
Depressed Gas is then sent to the HBJ pipeline for onward transportation.
5). LPG Plant
A part of sweet gas from outlet of GSU (about 5 MMSCMD) and the sweet
condensate from DPD are taken as feed to LPG Recovery Unit.State-of-the-
art cryogenic process Turbo-Expander has been used for the first time in
ONGC.The feed gas is first dried in molecular sieve dryers and then chilled
in a cold box to -30°C. The chilled vapour is expanded isentropically in
Turbo-Expander wherein temperature of the gas falls to -54°C. The heavier
hydrocarbons (C3+)get liquefied in the process, which are separated for
fractionation in LEF and LPG columns. The lean gas liberated from top of
LEF column is further compressed as per requirement of downstream
consumers. The products coming out from LPG as a top product and Naphtha
as a bottom product. A part of LPG is further distilled to obtain propane,
which is used as a refrigerant in LPG and DPD unit.
The LPG Plant is set up to recover LPG and Naphtha from the sweet gas
condensate at LPG unit & DPD condensate and supply lean gas to various

11. 11
local consumers like KRIBHCO, Heavy Water Plant, Essar, Reliance
Petrochemicals and Gujarat Gas Co. Ltd after of C2-C3 from the Gas at IPCL
Dahej.The LPG Plant was commissioned in December, 1987. Presently the
production of LPG from LPG Unit is 1501-1601 M3/Day, ARN Production
is 601-701 M3/Day
6). Condensate Fractionation Units
The Sour Condensate is treated in this unit to remove H2S to produce LPG
and NGL. The slug catcher condensate at 96-54 kg/cm2 abs and 20- 33°C is
flashed and the flash vapour forms feed to the Gas sweetening Unit.
Hydrocarbon condensate is then stripped off of H2S in the stripper and the
condensate is fractionated to recover LPG and NGL. NGL forms the
feedstock for Kerosene Recovery Unit. The stripper overhead vapour is
compressed and sent to the Gas Sweetening Unit.
7). Sulphur Recovery Units
The purpose is to convert acid gas with around 5% mole H2S and 85% mole
CO2 into elemental sulphur.Acid gas from the Gas Sweetening Unit enters
the oxidizer/ absorber wherein it comes in contact with the Catalytic LOCAT
solution and is converted into Sulphur. Air is introduced for regeneration of
the catalyst; Sulphur Slurry from the bottom of the oxidizer is then melted
and separated into liquid Sulphur and LOCAT solution. The LOCAT
solution is recirculated back to the oxidizer/ absorber. The liquid Sulphur
after preconditioning is converted into Sulphur pastilles in the Rotoformer
Unit.
8). Kerosene Recovery Unit
NGL produced from CFU is given value addition in KRU by way of
producing Naphtha, Superior Kerosene Oil (SKO) /Aviation Turbine Fuel
(ATF) and High-speed Diesel (HSD).The hot NGL is fed to Naphtha Column
for distillation from where Naphtha is recovered as a top product. The bottom
stream is fed to the Kerosene column through the gas fired furnace for further
fractionation. Kerosene/ATF is recovered from top of the Kerosene Column
and HSD is recovered from the bottom. A suitable chemical additive is added
in ATF to maintain electrical conductivity, and storage stabilizer for HSD
before these products are sent to storage.

12. 12
9). Caustic Wash Unit
The LPG from Condensate Fractionation Units (CFU) contains up to 20 ppm
H2S which has to be removed to less than the permissible limit of 4 ppm in
Caustic Wash Unit (CWU) before it is sent for storage in Horton Spheres.
The LPG is passed through the Absorber (containing caustic solution) and
sand filter to wash and remove H2S. Make up caustic lye is added for
maintaining the quality of solution.
10). Cogeneration Plant
Electric power to all the facilities and ONGC township at Hazira is supplied
by cogeneration power plant through three gas turbine generators. These
turbines are based on total energy conservation concept. The heat energy of
gas turbine exhausts is used for generation of high, medium and low pressure
steam for use in various process units. Excess power from the plant is
wheeled to GEB grid revenue generation.
11). Utilites & offsite
Hazira plant is self-contained for all the utilities & offsite facilities such as
water system, air system, inert gas system, effluent treatment plant product
storage & dispatch fire and safety system, required for safe and smooth
operation of the plant.
12). Product Terminal
Following product disposal facilities are available at Product Terminal.
1.Rail loading facilities are available to dispatch LPG and Naphtha.
2. Road loading facilities are available to dispatch LPG, HSD and ATF.
3. The pipeline facilities are available to dispatch
i)LPG to IOC and BPCL Bottling at Hazira.
ii) Naphtha to Export Ship, KRIBHCO, HPCLDepot, NTPC, Reliance.

13. 13
MECHANICALLY IMPORTANT
EQUIPMENTS IN PLANT
 PUMP-: A pump is a device that moves fluids
(liquids or gases), or sometimes slurries, by mechanical action
 CENTRIFUGAL PUMP
 SCREW PUMP
 RECIPROCATING PUMP
 GEAR OIL PUMP
 COMPRESSOR-: An air compressor is a device that converts
power (using an electric motor, diesel or gasoline engine, etc.)
into potential energy stored in pressurized air (i.e., compressed air).
 CENRIGUGAL COMPRESSOR (3-STAGE)
 RECIPROCATING COMPRESSOR
 SCREW COMPRESSOR
 HEAT EXCHAGER-: A heat exchanger is a device used to
transfer heat between a solid object and a fluid, or between two or
more fluids. The fluids may be separated by a solid wall to prevent
mixing or they may be in direct contact.
 SHELL AND TUBE EXCHANGER
 PLATE HEAT EXCHANGER

14. 14
 BOILER-: A boiler is a closed vessel in which water or
other fluid is heated. The fluid does not necessarily boil. The heated
or vaporized fluid exits the boiler for use in various processes or
heating applications
 BLOWER & FAN-: Blowers and Fans are machines whose
primary function is to provide and accommodate a large flow of air or
gas to various parts of a building or other structures. This is achieved
by rotating a number of blades, connected to a hub and shaft, and
driven by a motor or turbine.
 GAS TURBINE-: A gas turbine, also called a combustion turbine,
is a type of internal combustion engine. It has an upstream
rotating compressor coupled to a downstream turbine, and a
combustion chamber or area, called a combustor, in between.

15. 15
Centrifugal Pump:
Types of pump:

16. 16
Principle of centrifugal pump:
A centrifugal pump is one of the simplest pieces of equipment in any
process plant. Its purpose is to convert energy of a prime mover (a electric
motor or turbine) first into velocity or kinetic energy and then into pressure
energy of a fluid that is being pumped. The energy changes occur by virtue
of two main parts of the pump, the impeller and the volute or diffuser. The
impeller is the rotating part that converts driver energy into the kinetic
energy. The volute or diffuser is the stationary part that converts the kinetic
energy into pressure energy.
Note:All of the forms of energy involved in a liquid flow system are
expressed interms of feet of liquid i.e. head.
Generation of Centrifugal Force:
The process liquid enters the suction nozzle and then into eye (center)
of a revolving device known as an impeller. When the impeller rotates, it
spins the liquid sitting in the cavities between the vanes outward and
provides centrifugal acceleration. As liquid leaves the eye of the impeller a
low-pressure area is created causing more liquid to flow toward the inlet.
Because the impeller blades are curved, the fluid is pushed in a tangential
and radial direction by the centrifugal force. This force acting inside the
pump is the same one that keeps water inside a bucket that is rotating at the
end of a string. Figure A.01 below depicts a side cross-section of a
centrifugal pump indicating the movement of the liquid.
Liquid flow path inside a centrifugal pump

17. 17
Conversion of Kinetic Energy to Pressure Energy:
The key idea is that the energy created by the centrifugal force is
kinetic energy. The amount of energy given to the liquid is proportional to
the velocity at the edge or vane tip of the impeller. The faster the impeller
revolves or the bigger the impeller is, then the higher will be the velocity of
the liquid at the vane tip and the greater the energy imparted to the liquid.
This kinetic energy of a liquid coming out of an impeller is harnessed
by creating a resistance to the flow. The first resistance is created by the
pump volute (casing) that catches the liquid and slows it down. In the
discharge nozzle, the liquid further decelerates and its velocity is converted
to pressure according to Bernoulli’s principle.
Therefore, the head (pressure in terms of height of liquid) developed is
approximately equal to the velocity energy at the periphery of the impeller
expressed by the following well-known formula:
A handy formula for peripheral velocity.
This head can also be calculated from the readings on the pressure gauges
attached to the suction and discharge lines.
Pump curves relate flow rate and pressure (head) developed by the pump at
different impeller sizes and rotational speeds. The centrifugal pump operation
should conform to the pump curves supplied by the manufacturer. In order to
read and understand the pump curves, it is very important to develop a clear
understanding of the terms used in the curves.

18. 18
One fact that must always be remembered: A pump does not create
pressure, it only provides flow. Pressure is a just an indication of the
amount of resistance to flow.
General Components of Centrifugal Pumps
A centrifugal pump has two main components:
I. A rotating component comprised of an impeller and a shaft
II. A stationary component comprised of a casing, casing cover, and
bearings.
The general components, both stationary and rotary, are depicted in
Figure given below.

19. 19
General components of Single stage Centrifugal Pump
General components of multistage pump

20. 20
Difference between multistage pump and single stage
pump
1. Single stage pump refers to only one impeller pump, highest head is only
125 meter.
2. The multistage pump means to have two or more impeller pump, highest
head can more than 125 meters.
Multistage pumps in single stage pump head must match two levels
motor cases, by adding more impeller number to equip with level 4 motor,
which can improve pump using life and reduces the noise, but multistage
pumps maintenance is relatively more difficult than single stage pump.
3. Pump actual required head is less than 125 m, can according to pump room
area, pump prices (multistage pump price usually higher than single stage
pump) factors comprehensive consideration to choose single stage pump or
multistage pumps.
With the development of technology, single stage impeller pump
through improving the speed of the pump to improve pump head, can replace
multistage pumps, just the price is more expensive.

21. 21
Procedure for starting and stopping the
centrifugal pump
Starting -:
1. Confirm that the suction valves is opened fully and the discharge valve is
closed completely.
2. If the minimum flow line is installed , open its valve.
3. Open the vent valve again ,if supplied. After it was confirmed that air or
gas has vented , close the vent valve .
4. Start the driver in accordance with driver instruction and bring the pump
up to rated speed rapidly.
5. As soon as the pump is up to rated speed , open the discharge valve
slowly.
Do not let the pump run with the discharge valve closed .do not operate the
pump at less then minimum stable flow.
6. The temporary strainer in suction line must be checked periodically
whether it is not clogged so as not to cause a cavitation in the pump. This
screen should remain in the line for at least 24 hours after starting the pump
7. Check and record periodically the running conditions during operation for
the following items
ITEM FOR CHECK & RECORD NORMAL
Suction and discharge pressure 1. Normal pressure is indicated.
2. Fluctuation of gauge is small
Lubrication oil 1. Oil level is over half level of
oiler
2. Oil is clear
Mechanical seal 1. Leakage from mechanic seal is
no excessive
Temperature on the bearing housing 1. Maximum allowable temp is
90 degree Celsius
(max allowable oil temp is 82
degree Celsius
Vibration Vibration should be as less as
possible.
Noise 1. There is not abnormal noise
change

22. 22
External flushing line 1. Pressure gauge does not
indicate abnormal pressure
2. Surface temperature of external
flushing piping is nearly same
as temperature of eternal liquid
Quenching ( water or stream ) 1. Quench fluid is not sprayed out
from gland cover for
mechanical seal
Cooling water line 1. Circulation of the cooling
water can be confirmed by
sight flow
Note:
The pump should be shut down if it fails to develop its stable operation.
Investigate the cause of its unstable operation.
Stopping:
1. Close the distance valve gradually
2. Stop the driver immediately when the minimum line is provided , close the
discharge valve fully . open the minimum flow line valve fully , and then stop
the driver immediately.
3. After the pump stopped completely, close the discharge minimum flow line
valve fully
4. Close all valve in the auxiliary piping such as cooling flushing and quenching
line , in a while.
5. Close the suction valve fully.
NOTE-
1. Drain the water completely in cooling piping and jackets, in case that
freezing will be predicted.
2. In case of handling a liquid liable to solidity during shut down , clean the
pump interior well after stoppe the pump

23. 23
TROUBLESHOOTING INFORMATION
Troubles and their probable causes at operation are as follows.
No. Trouble Probable Cause
1. Failure to deliver liquid (1). Wrong direction of rotation.
(2). Pump not primed.
(3). suction line not filled with liquid.
(4). Inlet to suction pipe not sufficiently
submerged.
(5). Available NPSH not sufficient.
(6). Pump not up to rated speed.
(7). Total head greater than head for which
pump designed.
2. Pump does not deliver rated
capacity
(1). Wrong direction of rotation.
(2). Suction line not filled with liquid.
(3). Air leaks in suction line or stuffing box.
(4). Inlet to suction pipe not sufficiently
submerged.
(5). Available NPSH not sufficient.
(6). Pump not up to rated speed.
(7). Total head greater than head for which
pump designed.
(8). Viscosity of liquid greater than for
which pump designed.
(9). Mechanical defects-
a) Wearing rings worn
b) Impeller damaged.
c) Internal leakage resulting from
defective gaskets.
3. Pump does not develop
rated discharge pressure
(1). Gas or vapour in liquid.
(2). Pump not up to rated speed.
(3). Discharge pressure greater than pressure
for which pump designed.
(4). Viscosity of liquid greater than that for
which pump designed.
(5). Wrong direction of rotation.
(6). Mechanical defects-
a) Wearing rings worn
b) Impeller damaged.
c) Internal leakage resulting from

24. 24
defective gaskets.
4. Excessive power
consumption
(1). Speed too high.
(2). Either or both the specific gravity and
viscosity of liquid different from that for
which pump designed.
(3). Mechanical defects-
a) Misalignment
b) shaft bent
c) Rotating element dragging.
d) Packing too tight.
5. Vibration (1). Starved suction.
a) Gas vapor in liquid.
b) Available NPSH not sufficient.
c) Inlet to suction line not sufficiently
submerged.
d) Gas or vapor pockets in suction
line.
(2). Misalignment
(3). Worn or loose bearings.
(4). Impeller unbalance.
(5). Shaft bent.
(6). Foundation not rigid.
6. Stuffing box overheat (1)Packing too tight.
(2)Packing not lubricated.
(3)Wrong grade of packing.
(4)Insufficient cooling water to jackets.
(5)Insufficient external flushing liquid to
stuffing box.
7. Bearing overheat (1). Oil level too low.
(2). Improper or poor grade of oil.
(3). Dirt in oil.
(4). Failure of oiling ring.
(5). Insufficient cooling water circulation.
(6). Bearing too tight.
(7). Misalignment.

25. 25
8. Bearing wear rapidly (1). Misalignment
(2). Shaft bent.
(3). Vibration.
(4). Excessive thrust resulting from
mechanical failure of pump.
(5). Lack of lubrication.
(6). Bearing improperly installed.
(7). Dirt in oil.

26. 26
Types of Maintenance
 Preventive Maintenance
1. Predictive (Condition monitoring)
2. Periodic
Preventive or scheduled maintenance, where equipment or facilities are
inspected, maintained and protected before break down or other problems occur.
1. The care and servicing by personnel for the purpose of maintaining equipment in
satisfactory operating condition by providing for systematic inspection, detection, and
correction of incipient failures either before they occur or before they develop into
major defects.
2. Preventive maintenance tends to follow planned guidelines from time-to-time to
prevent equipment and machinery breakdown
3. The work carried out on equipment in order to avoid its breakdown or malfunction. It
is a regular and routine action taken on equipment in order to prevent its breakdown.
4. Maintenance, including tests, measurements, adjustments, parts replacement, and
cleaning, performed specifically to prevent faults from occurring.
 Corrective/Breakdown Maintenance
Corrective maintenance where equipment is repaired or replaced after wear,
malfunction or break down.
Corrective maintenance is a maintenance task performed to identify, isolate, and
rectify a fault so that the failed equipment, machine, or system can be restored to an
operational condition within the tolerances or limits established for in-service
operations.

27. 27
Preventive Maintenance
Precautions against damage of centrifugal pump.
Centrifugal pumps must be monitored regularly, correctly and accurately
according to a specific plan which is made by specially trained personnel. The
following six parameters should be regularly monitored to understand how a
pump is performing:
1. Suction pressure (Ps)
2. Discharge pressure (Pd)
3. Flow (Q)
4. Pump speed (N)
5. Pump efficiency (η)
6. Power.
The advantages regular monitoring of the pumps are -
1. No dismantling of the pump is necessary.
2. Offers cost savings and energy savings by increasing the pump
availability and reliability coefficients for pumps.
3. The time to maintain the pump set maybe predicted and planned more
accurately and in a qualified manner in line with predictive and planned
maintenance strategies.
4. If a flow meter is installed to measure process liquid flow, then the pump
monitor is able to verify the accuracy of the meter readings by calculating
‘Q’ from the empirical formula for power ‘P’.
In addition, it is very important to monitor some other conditions for centrifugal
pump during normal operation such as:-
1. Vibration monitoring.
2. Oil level and schedule oil Analysis.

28. 28
Centrifugal Pump Inspection Schedule
Centrifugal pump inspection should be done regularly. But for different the
level of checking varies with how frequently these pump inspections are carried
out. For during routine pump inspections only the easy to monitor factors such
as pressure, temperature, vibration etc can be checked. But during quarterly
inspections, shaft alignment and oil levels should also be checked. Some typical
inspection schedules are discussed below along with the checklist of activities
to be performed.
Routine inspections
Perform the following tasks whenever you check 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.
•Analyze 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.
Three-month inspections
Perform the following tasks every three months:
•Check that the foundation and the hold-down bolts are tight.
•Check the mechanical seal if the pump has been left idle, and replace as
required.
•Change the oil every three months (2000 operating hours) at minimum.
•Change the oil more often if there are adverse atmospheric or other conditions
that might contaminate or break down the oil.
•Check the shaft alignment, and realign as required.

29. 29
Annual inspections
Perform the following 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 do the following:
1. Disassemble the pump
2. Inspect it.
3. Replace worn parts.
Pump Maintenance Schedule
Routine maintenance (Can be made during pump operation)
Perform the following tasks whenever you perform routine maintenance:
 Clean bearing bracket from any oil if found.
 Check oil drain plug.
 Lubricate the bearings.
 Inspect suction and discharge flanges for any leak.
 Inspect pump casing for any unusual damage signs.
 Inspect the seal.
 If the pump is offline check the coupling and its shims for any damage.
 Make sure that the coupling guard s well tightened to pump base plate.
 Check that motor alignment bolts are all in place.

30. 30
Situation for shutdown of pump for
overhauling
 Fall-off in pump performance
 Excessive noise during pump operation
 Excessive vibration of pump
 Symptoms of corrosion or erosion trouble
Process involved in overhauling
a) Dismantling of CF pumps
 Pump has to be dismantled for overhauling
 Pump is first disconnected from the piping system
 Steps involved in dismantling a belt driven pump:
1. Remove the inlet and outlet flanges
2. Remove the bearing cap by removing the bolts holding it
3. Remove the grease cup and bearing lock nut
4. Remove the pedestal and take out the ball bearing, using a bearing
puller
5. Remove the belt shifter
6. Remove the nuts and bolts joining the casings and remove the
casing slowly, taking care not to damage the impeller and casing
rings
7. Remove the impeller nut

31. 31
8. Dismantle the rotating unit and remove the impeller slowly by
hammering back the shaft gently, using a wooden block
9. Remove the impeller from the rotating unit
10.Remove the pulleys using a pulley puller
11.Dismantle the stuffing box
b) Overhauling of impellers
 The eye, vanes, shrouds, wearing rings, passages and hubs are checked
 Corrosion, cavitation and erosion are accompanied by the wearing of the
impeller vane surfaces
 Corrosion is due to warp or holes in the thinned surfaces
 Impeller have to be replaced, if cavitation is severe
 Impeller have to be thoroughly cleaned before inspection
c) Balancing of impeller
 Badly worn or corroded impeller needs rebalancement
 Balancing of an impeller can be checked by pressing it on an arbor, the
ends of which rest on 2 parallel and level knife-edges, by hand
 If found unbalanced, the metal is removed from the heavy side
d) Repair of shaft
 Shaft is checked for bending with a dial gauge, by turning the shaft
between lathe centres
 If shaft is badly bent, it should be returned to the manufacturer
 Reconditioning of the shaft will require welding or metalling, followed
by rough finishing cuts

32. 32
 Final finishing is done by filing
e) Replacing of wearing rings
 Proper clearance of the wearing ring is important
 Increase in clearance results in leakage which decreases efficiency
 If wearing rings are worn out, they have to be replaced
f) Repair of shaft sleeves
 Shaft sleeves often get worn out when packed too tightly
 Reconditioned by welding or metalizing, followed by a rough finishing
cut
 If wear is excessive, shaft sleeves have to be replaced
g) Repair of Non-stationary Components
 Repair is negligible
 Bed plate is kept clean of grease and oil at regular intervals
 Joints and piping are checked regularly for leakage
 Foundations are kept clean
 Cracks in foundations are repaired in time
 Surface of casing is painted
h) Reassembling the parts of a CF pump
Steps involved are:
 Mount the pulleys on the shaft
 Mount the casing and stuffing box bushes on the shaft
 Gently mount the impeller on the shaft

33. 33
 Insert the impeller key carefully
 Adjust the impeller at its correct position and tighten the impeller unit
 Insert the gasket and grease it properly
 Mount the casing by tightening its nuts and bolts
 Insert the belt shifter at its correct position
 Insert the shaft sleeve and tighten it properly
 Mount the pedestal and align it properly by inserting the desired
packing (shims)
 Mount the ball bearing, on hand press, and tighten the bearing locking
nut. Do not hammer the ball bearing
 Mount the bearing cap

34. 34
Breakdown Maintenance
 Disassembly:
 Disconnect auxiliary piping and remove coupling spacer. It is not
necessary to disconnect suction and discharge piping when
dismantling the pump.
 Pull off pump by half coupling by using coupling puller.
 Turn set plate attached to gland cover for mechanical seal into groove
in shaft sleeve and lock in position. Loosen shaft sleeve and lock in
position. Loosen shaft sleeve drive collar.
 Loosen setscrews holding deflector ring.
 Disassemble bearing housing as follows.
1. Thrust bearings
If pump is equipped with ball thrust bearing, dismantle in the
following sequence.
a. After bearing housing cover is slidden off, dismantle
bearing housing cover. Bearing housing and oiling ring.
b. Bearing lock nut & washer. Bearing thrust collar. Thrust
ball bearing and bearing space ring.
c. Bearing housing cover and deflector ring.
2. Radial Bearings
If pump is equipped with ball radial bearing. Dismantle tile in the
following sequence.
a. After inner bearing housing cover is slid den off
.Dismantle outer bearing housing cover, bearing housing and
oiling ring.
b. Bearing retainer or bearing adapter and radial ball bearing.
c. Bearing spacer ring or bearing lock nut and washer.
d. Inner bearing housing cover and deflector ring.
3. Remove nut holding gland cover and slide gland cover including
mechanical seal assembly and shaft sleeve off start.
4. Remove head with head gasket and inner head gasket using
jackscrew.
5. Pull out internal assembly and dismantle in the following sequence.
a. Shaft sleeve key
b. Impeller lock nuts, Impellers, Case spacers, Spacer sleeves
and Impeller keys.

35. 35
 Cleaning
After disassembly, clean all the parts as follows.
1. Remove scale or similar deposits with cleaning solvents.
2. Wash and blow out which air, inside of casing.
3. Clean bearings and inside of bearing housing by washing in
solvents. Use cooling clothes for wiping.
 Inspection
Inspect all the parts in accordance with following particular attention.
1. Check all the parts for dirt, wear and damage.
2. Check shaft for straightness.
3. Replace parts that cannot be repaired if the clearance of the
rotating parts has reach the limit value for replacement, wearing
parts should be replaces.
 Repair
 Case and head wearing rings and impeller wearing rings.
1. Remove worm wearing ring for machining
2. Install new rings and screw the se screws.
3. Confirm bicameral clearance of new wearing rings.
 Case spacer bushing, packing box bushing, and comb. Packing box
bushing and lantern ring and stationary oil baffle.
1. Remove worn parts by putting a plate on it and striking with
hammer.
2. Strike and fit new one with hammer. Stationary oil baffle must
be fitted so that its drain hole is located to underside.

36. 36
 Reassembly
 Assemble rotating elements and check for concentricity.
 Carefully remove the parts of rotating elements from shaft.
 Assemble internal parts of the shaft in the following sequence.
1. Impeller keys, spacer sleeve, case spacer, impellers and impeller
lock nuts.
 Fix head in the internal assembly. Align the hole in the case spacer
with the locating pin in head.
 Install the internal assembly with head, head gasket and inner head
gasket in case. Tighten case nut firmly. Case and head are fitted in
metal to metal.
 Check for concentricity and squareness of the rotor in the following
sequence.
1. Assemble thrust bearing and housing as indicated under thrust
bearings assembly section.
2. Assemble radial bearing and housing as indicated under radial
bearings assembly section.
3. Rigidly clamp a dial indicator to the pump shaft. Check for the
concentricity of the packing box bore and for squareness of end
face of the packing box and bearing housing.
4. Dismantle both bearing housing.
 Slide shaft sleeve key, shaft sleeve with rotating ring for the
mechanical seal, gland with stationary ring for mechanical seal, shaft
sleeve drive collar and deflection ring onto shaft. Engage set plate
with the groove in shaft sleeve and lock in position.
 Assemble the bearing housing as follows.
1. Thrust bearings
If pump is equipped with ball thrust bearing, assemble in the
following sequence.
a. Slip on bearing housing cover with gasket. Its oil drain
hole shall be located to underside.
b. Bearing spacer ring, thrust ball bearing, bearing thrust
collar and bearing lock nut and washer.
c. Bearing housing, oiling and bearing housing cover with
gasket. Tighten nuts holding bearing housing to case
evenly.

37. 37
2. Radial Bearings
If pump is equipped with ball radial bearing, assemble in the
following sequence
 Slip on bearing housing cover with gasket. Its oil drain
hole should be located to underside.
 Bearing adapted with radial bearing and bearing lock nut
and washer or bearing spacer ring ,radial ball bearing and
bearing retainer
 Bearing housing, oiling ring and outer bearing housing
cover with gasket. Oil drain hole of bearing housing
cover shall be located to underside. Tighten nuts holding
bearing housing to case evenly.
9. Install deflector ring by setscrews. Clearance between deflector ring
and stationary oil baffle is about two.
10. Bolt the gland cover to casing.
Set the shaft sleeve drive collar, turn set plate out of shaft sleeve groove
and lock into position.
11. Turn shaft by hand to be sure bearing rings and bushings is free and
clear.
12. Install flexible coupling.
13. Check alignment of pump and driver. Correct if necessary.
14. Bolt coupling spacer and connect auxiliary piping.
 Parts ordering
When ordering parts for spare or replacement, the following information must
be given.
1 Pump type and serial no. given on the nameplate.
2 Part name given on cross sectional drawing.
3 Quantity of parts.
4 Complete shipping instructions.
Recommended replacement interval for wear parts.
Utilise the replacement interval as guide in order to prepare the minimum spare
parts required for the maintenance at the site.

38. 38
No. Name of parts Replacement interval
1 Gaskets Every overhaul
2 Wearing rings When the diametric clearance has
increased 100% for minimum
clearance or when the significant drop
of pump performance is admitted.
3 Spacer sleeves and bushings Same as wearing rings.
4 Mechanical seals One year.( When the leakage from
mechanical seal has be occurred by
damage on seal face)
5 Shaft sleeves Two years.( When the surface of shaft
sleeve is worn)
6 Ball bearings Two or three years.( When increase of
noise or vibrations is admitted or
when abnormal rubbing sound is
admitted to the bearing)
7 Sleeve bearings When the diametric clearance has
increased 50% for minimum
clearance.

39. 39
Thank You