1. IOP
Pumps
Basic
Concepts
Pumpsin
IOP
HALDIA PETROCHEMICALS LIMITED
TRAINING PERIOD: 18.05.2015 – 17.06.2015
Report on:
Under the guidance of
Mr. Yuvaraj Elumalai
Manager, IOP, HPL
and
Mr. Sanjoy Kumar Dey
Deputy Manager, IOP, HPL
By
Subham Shit
Mechanical Engineering Department
Indian Institute of Engineering Science and Technology, Shibpur
Howrah – 711103.
Discussion on Pumps used in IOP
(Integrated Offsite and Utilities Plant)

2. Acknowledgement
I would sincerely like to thank the Human Resource Department, of Haldia
Petrochemicals Ltd. for their constant assistance to help me achieve this training
successfully. My sincere regards to Mr. Badal De, DGM of IOP Deparment for
helping me realise the dos and don’ts pertaining to this specific training report
under IOP and also helping me in all other sort of ways throughout the entire
duration of my work. I would like to thank Mr. Yuvaraj Elumalai, Manager, IOP
who opted to become my training guide and it was owing to him that my training
has become a success. I would also like to thank Mr. Sanjoy Kumar Dey (Deputy
Manager, IOP), Mr. Rakesh Ranjan (Assistant Manager, IOP), Mr. Sudipta Sarkar,
Mr. Srinath Mohanty and Mr. Gaurav Paul (all Engineers of IOP) for their sincere
help, guidance and hours of teaching and learning I gained from them that I have
finally been able to jot down this training report. I am sincerely indebted to
specially Mr. Sudipta Sarkar & Mr. Srinath Mohanty, for the large chunks of time
they spent every now and then to answer all of my doubts and questions and
scrutinise my report, pointing my mistakes and guiding me to the correct path.
Lastly, I would like to thank all other various members and workers of IOP, who
have helped me in one way or another during this month-long training.
Subham Shit
Summer Trainee,
Haldia Petrochemicals Ltd.
Mechanical Engineering Department
IIEST, Shibpur

3. C O N T E N T S
1. CHAPTER 1: A REPORT ON IOP
1.1 Introduction 1
1.2 NCR (North Control Room) 1
1.2.1 Cooling Water System
1.2.2 Water Treatment System
1.2.3 DM Water System & CPS
1.2.4 Compressed Air System
1.2.5 Naphtha Tanks
2
3
5
6
7
1.3 ECR (East Control Room) 8
1.3.1 Gantry Loading and Unloading System
1.3.2 Tank, Sphere and Bullet Storage Systems
8
9
1.4 SCR (South Control Room) 12
1.4.1 Waste Water Treatment Plant (WWTP)
1.4.2 Flare System
12
14
2. CHAPTER 2 : PUMPS IN IOP
2.1 Introduction 15
2.2 Classification of Pumps 15
2.2.1 Classification of Dynamic Pumps
2.2.2 Classification of Displacement Pumps
15
16
2.3 Cavitation 16
2.3.1 What is Cavitation?
2.3.2 Source of Cavitation
2.3.3 Cavitation types and its prevention
16
16
17
2.4 Net Positive Suction Head (NPSH) 19
2.4.1 What is NPSH?
2.4.2 Requirement of NPSH
2.4.3 Difference between NPSHA and NPSHR
19
20
20
2.6.1 Function of Casing
2.6.2 Types of Casing
23
24
24
2.8.1 Introduction
2.8.2 Basic Components
2.8.3 Types of Mechanical Seal & Applications
2.8.4 Advantages and Disadvantages of Mechanical Seal
2.8.5 Different Types of Plans
26
26
26
27
27
 REFERENCES 39
2.5 Types of Impeller 21
2.6 Pump Casing
2.7 Suction Piping 24
2.8 Mechanical Seal 26
2.9 Performance Curve of Centrifugal Pumps 29
2.10 Pumps in IOP 30

4. A REPORT ON IOP
Integrated Offsite and Utilities Plant
A B S T R A C T
This report consists of
description about three
controlling units under IOP
along with their systematic
operations on various systems
with different flow diagrams.
CHAPTER 1

5. 1
IOP
(Integrated Offsite and Utilities Plant)
1.1 Introduction
1.2 NCR (North Control Room)
Under North Control Room (NCR) the following activities are done.
NCR
Cooling Water System
(Supping Cooling water throughout all heat exchangers of HPL
where water is used as coolant)
DM Water System and Condensate Polishing System
(De-Mineralized Water Production and supply)
Raw Water Treatment Plant
(Supplying high quality water for cooling tower make-up)
Pre-treatment Plant
(Supplying high quality water for DM Plant feed)
RO Plant
(Water treatment using Reverse Osmosis Process)
Compressed Air System
(Supplying Instrument Air and Plant Air)
Steam Distribution System
(Suppling Stream and Power from Captive Power Plant[CPP])
Raw Material Storage System
(Storage of Process Grade Naphtha in Naphtha Tanks)
IOP (Integrated Offsite & Utilities Plant) comprises of three basic controlling departments or
sections - NCR (North Control Room), ECR (East Control Room) and SCR (South Control
Room). These sections each consists of some sub-divisions. NCR consists of cooling water
system (Cooling Towers & Mist Cooling System), DM water Plant, RO Plant, Water Treatment
Plant, Pre-treatment Plant, Compressed Air Distribution System and Stream Distribution
System. ECR has Gantry loading and unloading system, Tank, Sphere & Bullet Storage and
Transport for different types of materials (Raw material, intermediate and finished product).
SCR consists of Waste water treatment plant and Flare System.

6. 2
1.2.1 Cooling Water System
 Basic Description:
Cooling water is used to remove unwanted heat from industrial manufacturing processes.
Temperature is one of the most critical parameter of concern in any chemical process
industry.
Cooling water system basically consists of:
a. Cooling water basin and sump
b. Circulating Pumps
c. Hot Water Channel and distribution system.
d. Packing for heat transfer
e. Fan
f. Supply & return Header
g. Side stream filter.
Temperature reduction takes place by evaporation of equivalent quantity of water.
Corrosion, scale deposition and microbial growth are the major points of concern in cooling
water system. To control it, sulfuric acid, chlorine, corrosion inhibitor, scale dispersant,
biocide and bio-dispersant are dosed under cooling water treatment program.
 Equipment(s) in cooling water system:
In HPL, we have 1 no. of Mist Cooling System and 2 nos. of cooling towers to cater the
demand of cooling water in NCU, NCAU and polymer plants separately.
 Cooling Tower - 01
o Caters to the demand of cooling water in NCU, NCAU and CCR & Olefin Building.
o 9 cells of capacity 3500 m3
/h each.
o Range: 120
C, Approach: 60
C, Efficiency: 68.5%
o Nine pumps (7W+2S) of capacity 4500 m3
/h circulate the water to the plants.
o Side stream filters have been provided to control the suspended particles in the
circulating water.
 Cooling Tower - 02
o Caters to the demand of cooling water in HDPE, LLDPE, PP and all IOP control
rooms.
o 7 cells of capacity 3500 m3
/h each.
o Range: 80
C, Approach: 50
C, Efficiency: 63%
o Six pumps (5W+1S) of capacity 4500 m3
/hr circulate the water to the plants.
o Side stream filters have been provided to control the suspended particles in the
circulating water.
 Mist Cooling System
o Caters to the demand of cooling water in all associated units.
o Total no. of nozzles: 5 (Nozzles in 1 Nozzle Arrangement) × 23 (Nozzle
Arrangements in one 6’’ header) × 10 (No. of 6’’ headers) = 1150 with spiral holes for
spin flow.
o The nozzles spraying hot water vertically into the atmosphere (Evaporative cooling).
o Range: 7 – 8 0
C.

7. 3
 Flow Diagram of cooling water system:
1.2.2 Water Treatment System
The water treatment system can be classified or represented in the following form.
Cooling Water Sump
Side Stream Filters
Acid
Chlorine
Corrosion
Inhibitor +
Non-oxidizing
Biocide + Scale
Dispersant +
Bio-dispersant
Makeup water
Return
Header
Supply Header
RawWater
Storage in Ponds
Water Treatment
Plant
CT - 01
CT - 02
CT - CPP
CT - Praxair
Drinking Water
Pre Treatment Plant
DM Plant
& CPU
Plant Water System
Fire Water System

8. 4
 Raw Water Treatment Plant & Pre Treatment Plant:
Raw water is used for cooling water makeup, DM plant feed, plant water, drinking water and
fire water in our plant. Raw water is received from PHED through dedicated pipelines. Although
it is a filtered water, it may not meet the stringent standard for using it directly in cooling water
makeup and DM plant feed. Raw water treatment plant and pre-treatment plant has been
provided to supply high quality water for cooling tower make-up and DM plant feed
respectively.
o Capacity of Raw Water Treatment Plant – 2600 m3
/h.
o Capacity of Pre-treatment Plant – 500 m3
/h
Pre-chlorination, chemical coagulation and flocculation, clari-flocculator/reactor clarifier
and high rate gravity sand filters have been provided to control biological growth and reduce
suspended solids and turbidity to acceptable levels.
 Raw Water and Treated Water Characteristics:
 Flow Diagram of Raw Water Treatment Plant:
Raw Water Treatment Plant Pre-Treatment Plant
Feed Water Treated Feed Water Treated
pH 7.5-8.5 7.5-8.5
pH 7.5-7.7 7.5
Turbidity, NTU 100-200 < 1.0
TSS, mg/L 300 (max.) < 5
TSS, mg/L 100 (max.) < 0.5
Stilling Chamber Flash MixerParshall Flume
Sand
Filter Clari-flocculator
Filtered
water for CT-
makeup, DM
Plant &
Drinking
Water
Chlorine Lime + Alum
Polyelectrolyte

9. 5
1.2.3 DM Water System & CPS
 Basic Description:
Natural water contains dissolve salts like carbonates, bicarbonates, sulfates and chlorides of
Calcium, Magnesium and Sodium and other impurities like silica, metals etc. Some of these salts
have very low solubility in water at higher temperatures. When water is to be heated with in a
boiler for steam generation, scale forms due to deposition of low solubility salts. e.g.
Ca(HCO3)2
∆
→ CaCO3 + H2O + CO2
Water is also used directly in the process in polymer plants. Any contamination may
adversely affect the quality of product. Complete removal of all dissolved salts is necessary in
the above cases. DM (De-mineralization) water plants remove these salts by passing it through
different resin beds (Cation and anion). These resins remove the cations (Ca+2
, Mg+2
) and anions
(Cl-
, SO4
-2
) by replacing them with free ions. Ion exchange resins are porous materials which
contain an inert base attached to which, are free ions. These ions are free to move about within
the resin structure and can be replaced by other ions of the same type from a surrounding
solution.
 Flow Diagram of DM Water Plant:
 Full Forms:
ACF - Activated Carbon Filter, WAC - Weak Acid Cation Exchanger, SAC - Strong Acid Cation
Exchanger, WBA – Weak Base Anion Exchanger, SBA – Strong Base Anion Exchanger, MB –
Mixed Bed Exchanger.
WBA
DM Water
Tank
ACF WAC SAC Degasser
Tower
SBAMB
For
Distribution
Pre-treated
Water

10. 6
 Flow Diagram of Condensate Polishing System(CPS):
1.2.4 Compressed Air System
Compressed Air System is one of the basic systems in the plant. It supplies plant air and
instrument air which is very necessary for many instruments used in the polymer units.
 Equipment(s) in compressed air system:
o 3 Stage Centrifugal Air Compressor (with water intercoolers between 2 consecutive
stages) – 3 units.
o Single acting, double stage, double cylinder Reciprocating Air Compressor – 1 unit.
o Plant Air Receiver
o Instrument Air Dryer
o HP Air Compressors
o HP Air Receiver
The compressed air system is a high noise zone area. In the three 3 stage centrifugal
compressors air is first compressed in the 1st
centrifugal compressor (low pressure, stage 1) then
it comes inside the 1st
intercooler and then it is compressed in the 2nd
centrifugal compressor
(medium pressure, stage 2) and it comes inside the 2nd
intercooler and then it is compressed in
the 3rd
centrifugal compressor (high pressure up to 7.6 kg/cm2
, stage 3). After that the high
pressurized air comes into the air receiver. The compressed air is then divided into two parts
one is for producing plant air and another is for instrument air. For plant air, the hot compressed
air is again cooled by cooling water and for instrument air, the hot compressed air is passed
through air dryer (using activated Alumina). Thus by removing moisture, instrument air is
produced.
Generally, Air receiver has pressure 24.5 kg/cm2
(usually it varies 25-29 kg/cm2
) as
maintained by the process. If the pressure in air compressor falls below 25 kg/cm2
, the
reciprocating air compressor becomes active automatically and it pressurizes the air receiver up
to 28 kg/cm2
. This is the main function of the Reciprocating air compressor.
DMW CWS
Raw
Condensate
Condensate/DMW
Exchanger
Trim Cooler
Condensate Tank
Activated
Carbon Filter
Filter
Mixed bed
Exchangers
DM
Water

11. 7
 Flow Diagram of Compressed Air System:
1.2.5 Naphtha Tanks
Naphtha Tanks are used for storing process grade naphtha.
Roof Appurtenances: Level Transmitter (both Servo Type & Float Type), Deck Manhole (with
ladder), Rim vent (with wire mesh), Emergency drain, Bleeder vent, Manway in each
compartment, Gauge hatch with cover. Shell Appurtenances: Manhole, Product inlet/outlet,
Siphon drain, Roof drain, Foam connection.
CWS Plant Air
Receiver
Instrument
Air Dryer
Desiccant:
Activated
Alumina
Air
Compressors
HP Air
Compressors
HP Air
Receiver
Plant Air Distribution
Instrument Air Distribution
Fig. 1.3.2: Diagram of Naphtha Tank (41-T-001 A/B/C/D)
Source: Haldia Petrochemicals Ltd.

12. 8
1.3 ECR (East Control Room)
Under East Control Room (ECR) the following activities are done.
1.3.1 Gantry Loading and Unloading System
The tanks which are used for transporting hydrocarbons from one place to another is unloaded
and loaded in this system. Specifically, this system has reciprocating compressors (like – Corken
Gas Compressor).
The entire gantry loading and unloading system can be classified or represented in the following
form.
ECR
Gantry Loading and Unloading System
(This System is basically used to load and unload the tanks used for
hydrocarbon transport)
Tank, Sphere and Bullet Storage Systems
(Depending upon the vapor pressure of the liquid at atmospheric
temp different types of storage is used)
Transport for different types of materials
(Raw material, intermediate and finished product transport)
MS Production
(Motor Spirit is produced in ECR)
GantryLoadingandUnloadingSystem
Pressurized Gantry
Unloading Bay
(Raw Material)
LPG, Propylene
(Vertical Multistage Barrel Type
Centrifugal Pump)
Propylene Unloading (Corken Compressor)
Fuel Gas Naphtha (FGN) Unloading
Butene-1 Unloading
Loading Bay
(Product)
LPG/C4 Raffinate
Butadiene
Non-Pressurized Gantry
Unloading Bay
(Raw Material)
Hexane Unloading
Loading Bay
(Product)
MS (Motor Spirit)
PY Gas
CBFS (Carbon Black Feed Stock)
Benzene

13. 9
1.3.2 Tank, Sphere and Bullet Storage Systems
 Requirement of different type of storages:
Depending upon the vapour pressure of the liquid at atmospheric temp different types of
storage is required.
o If vapour pressure is > 1 kg/cm² liquid is to be stored in sphere or bullet.
o If 0.5 kg/cm² < vapour pressure < 1 kg/cm² liquid is to be stored in doom roof tank.
o If vapour pressure < 0.5 kg/cm² liquid is to be stored in atmospheric tank.
 Why Sphere, Bullet and Tank shapes are used for storage devices?
Generally, Spheres are constructed at the place of installation because of its huge size and
difficulty to transfer from one place to another. As in HPL, a sphere needs 12 no. of columns for
its support at the ground. In spite of having these problems regarding sphere, it is used in large
no. for storing raw materials (41-V-001, 41-V-002A/B/C), intermediate products (42-V-
001A/B/C/D, 42-V-003A/B/C/D) and finished products (43-V-001A/B/C/D, 43-V-002A/B/C/D).
The basic reason behind this is that for a sphere the hoop stress (𝜎ℎ) and the meridional stress
(𝜎 𝑚) are equal. This value is given by:
𝜎ℎ
𝑟
+
𝜎 𝑚
𝑟
=
𝑝𝑖
𝑡 𝑠𝑝
⇒ (σmax)sphere =
pi
d
4𝑡 𝑠𝑝
Now, for a cylinder (or tank), longitudinal stress (𝜎𝑙) is half of the hoop stress (𝜎ℎ). This can be
derived as:
𝜎ℎ
𝑟
+
𝜎𝑙
∞
=
𝑝𝑖
𝑡 𝑐𝑦
⇒ (σmax) 𝑐𝑦𝑙𝑖𝑛𝑑𝑒𝑟 =
pi
d
2𝑡 𝑐𝑦
𝜎𝑙 ∙ 2𝜋𝑟𝑡 𝑐𝑦 = 𝜋𝑟2
𝑝𝑖 ⇒ 𝜎𝑙 =
pi
d
4𝑡 𝑐𝑦
So, we can clearly say if a sphere and a cylinder of same material with same diameter is
subjected to same internal pressure, then the required thickness of the sphere (𝑡 𝑠𝑝) will be half
of the thickness of the tank (𝑡 𝑐𝑦).
Putting it another way, a sphere of
same material with same diameter
and thickness of a cylinder can
sustain twice of the internal
pressure developed in the
cylinder. So, sphere is better than
a cylinder in case of material
usage point of view. But,
construction or manufacturing
cost is more in case of a sphere
compared to a cylinder or tank.
For utilizing both transportability & maximum stress along with less construction cost,
bullet type structures are made. Bullet is nothing but a cylinder with two thin hollow hemi-
spherical ends. Bullet can be moved from one place to another and as per HPL, bullets are at
high pressure (150 kg/cm2
, gauge) while spheres are pressurized at 25-27 kg/cm2
(gauge). But
while manufacturing of a bullet there may have some problems regarding the joining of two
different thicknesses at the two ends.
Fig. 1.3.2: Schematic Diagram of a Bullet Storage

14. 10
 Storage Classifications:
N2 Blanketing is nothing but pressurising with nitrogen gas inside a closed tank. The nitrogen
blanketing is done by operating two valves: PSV (Pressure Safety Valve) & VRV (Vacuum Release
Valve). The reason behind the nitrogen blanketing is for safety purpose. Generally, the vapour
pressure of liquid hydrocarbon is near atmospheric pressure. So, vapour generation can happen
in normal temperature and pressure and the concentrated vapour linkage may lead to fatal
accident. To avoid that, the liquid hydrocarbons must be pressurised by any inert gas like
nitrogen. As little leakage cannot be avoided, it is better to be diluted with N2 because diluted
hydrocarbon vapour will be less accident-prone. This is main reason of using nitrogen
blanketing.
Suppose, in a Dome Roof Tank or Internal floating roof tank, if the liquid hydrocarbon level
decreases i.e. if floating roof (for Internal floating roof tank) falls down, as a result the nitrogen
inside the chamber will expand. So, the available nitrogen pressure inside the chamber will
decrease and if pressure reduces below atmospheric pressure, the tank may undergo plastic
deformation due to pressure difference between the inside & outside surface. To avoid this, VRV
(Vacuum Release Valve) is used here. It supplies extra amount of nitrogen inside the tank which
maintains the pressure accordingly. On the other side, if the liquid hydrocarbon level increases
then the chamber will be pressurized, so it can be damaged. To avoid that, PSV (Pressure Safety
Valve) is used. It reduces the pressure by releasing nitrogen & hydrocarbon mixture from the
tank. This is the main process of nitrogen blanketing.
Typesofstorage
High Pressure
Bullet
(for Propane, Hydrogen)
Medium Pressure
Sphere
(for Propylene, Ethylene,
Butadiene, C4 Mix, C4
Raffinate/ Mix Butane,
Butene-1 etc.)
Low
Pressure
Low pressure tank
Dome Roof Tank
[for Cyclopentane, RPG, HPG
etc (some are with 0.2 Kg/cm2
N2 blanketing)]
Atmospheric
tank
External Floating roof
(for Naphtha, old MS etc.)
Cone roof
(for CBFS, Acid, Caustic storage etc.)
Cone roof & IFR tank with N2 blanketing
(for Benzene, BEU feed stock etc.)
Cone roof & IFR tank without N2 blanketing
(for New MS, imported Hexane, FGN etc.)
 What is N2 Blanketing? Why is it used?

15. 11
 Different types of Tanks:
 Butadiene chilling system:
*Propylene Compressor is one of the critical equipment in IOP, used in Butadiene chilling system (vapour
compression refrigeration system using propylene as refrigerant).
Another critical equipment is H2 Compressor (Vertical type diaphragm compressor) used for storing H2
coming from NCAU at a pressure 30 kg/cm2
g to about 120 kg/cm2
g in H2 Storage system (2 no. of bullets).
Floating roof
Internal Floating roof
N2
PCV
Internal Floating roof with N2
blanketing
PT
PIC
N2
FY
VRV
PSV
DOME ROOF TANK
To gantry
HX
K
O
D
Propylene
compressor*
(Double Acting,
Single Stage,
double cylinder
Reciprocating
compressor)
CW
LIC
Vapour balance
header
Propylene
condenser
Propylene
accumulator

16. 12
1.4 SCR (South Control Room)
The main aim of SCR is pollution control. A Petrochemical Industry can have two types of
harmful wastes: one is waste water and another is excess hydrocarbons. So, it is mandatory to
convert these harmful wastes to treated wastes or certain compounds which will not pollute the
environment up to a certain limit as per given by the pollution control board.
Under South Control Room (SCR) the following activities are done.
1.4.1 Waste Water Treatment Plant (WWTP)
 General Description:
 WWTP has been designed to treat all the liquid effluent generated during process and
otherwise from all process plants and IOP.
 Plant has been designed to treat-
o Process effluent – 3600 m3
/d
o Sanitary Effluent – 490 m3
/d
o Cooling Tower Blowdown – 26,220 m3
/d
o DM Neutralization Waste – 2000 m3
/d
 Major pollutants in the liquid effluent are –
o Suspended solids
o Free and emulsified oil
o Sulfide
o Phenols
o Dissolved/Soluble organic material exerting BOD/COD.
 Treatment scheme consists of -
o Physical processes to remove free oil, floating particles and suspended particles.
o Physico-chemical processes for pH adjustment, coagulation and flocculation,
sulfide removal, de-emulsification of oil and subsequent removal by DAF process.
o Biological process such as Activated sludge process for removal of bio-degradable
organics.
o Sludge collection, thickening and centrifugation.
o Slop oil collection and storage.
 Full Forms:
o WWF : Wet Weather Flow
o DAF : Dissolved Air Flocculation
o CTBD : Cooling Tower Blow Down
o DOPE : De-Oily Poly-Electrolyte
o TPI : Tilted Plate Inter-separator
o DWPE : De-Watering Poly-Electrolyte
o DAP : Di-Ammonium Phosphate
SCR
WWTP
(Waste Water Treatment Plant)
Flare System
(Combustion of excess hydrocarbons)

17. 13
FlowDiagramofWWTP:
Urea
DWPE
Stream1+3+4
TPI-01
DWFBarScreen
andGrit
Chamber
DWF
Stream-05
ReceivingSump
Stream-09
WWFBarScreen
andGrit
Chamber
WWF
DrySlop
OilTankerLoading
SurgePond
16700m3
SlopOil
CTBDPonds
2x14110m
3
Treated
Effluent
Sump
Aerator
Sump
GuardPond
2x4090m
3
TPI-02
WetSlop
OilSump
Centrifuge
EQ.Tank
pHAdj.
Tank
Flash
Mixing
Tank
SanitaryBar
Screenand
Grit
Thickener
Clarifier
Chemical
AndOily
Sludge
Sump
Stream-07
Stream-08DisposaltoStrom
WaterChannel
Recycleto
SurgePond
SupernatantFlowSludgeCakefor
Disposal
2x95
m3
/h
Bio-sludge
Recirculation
Flocculation
Tank
DAP
DAF
Aeration
Tank
Stream-07
490m3/d
2x75
m3
/h
2x75
m3
/h
2x75
m3
/h
2x75
m3
/h
Stream-02AcidCausticAlumH2O2DOPE
Stream#01–NCU&AU
Stream#02–HDPE
Stream#03–LLDPE
Stream#04–PP
Stream#05–OWS
Stream#06–Sanitary
Stream#07–DMNeutralizationWaste
Stream#08–CoolingTowerBlowdown
Stream#09–KOD

18. 14
1.4.2 Flare System
Flare system has been provided for disposing hydrocarbon vapors/gases safely by burning at the
top of flare stack.
 Flare system consists of –
o Flare header- For collecting vapors/gases from process units, sphere farm and
gantry.
o Flare Knockout Drum – To remove/collect entrapped liquid droplets in flare vapor
stream.
o Water Seal Drum – To maintain positive pressure in the flare header by means of
water seal.
o Flare Stack – To carry the gases to sufficient height for safe dispersion.
o Molecular Seal – To reduce purge gas consumption.
o Flare Tip – Consists of pilot burners for continuous burning, steam for smokeless
flaring.
o Flame Front Generator - For remote lighting up the burner of flare tip.
o Blowdown Pumps – To transfer oil from KOD to storage tank.
 Fuel gas is provided to pilot burner for continuous burning. Nitrogen purging is done from
all dead ends of flare header to avoid vacuum formation and air ingress. Steam is used for
smoke suppression. 74” dia. header has been provided to collect flare gases.
o Design Load – 1286 MT/hr.
o Smokeless flare load – 100 MT/hr.
o Total height of the flare stack – 120 m
 Schematic Diagram of Flare System:
****
WSD
Stack
Mol. Seal
Flare
Tip
Steam for smokeless combustion
Flame Propagation Lines – 4 nos.
Fuel Gas Supply –
4 nos.
Oil to
WWTP
From
Process
Plants +
Gantry etc.
Plant Water
KOD

19. PUMPS IN IOP
Centrifugal Pumps & Reciprocating Pumps
A B S T R A C T
Generally Centrifugal pumps are
the mostly used pumps in IOP. It
has broad applications in different
sectors for better reliability with
low head & high discharge. Beside
this, Reciprocating Pumps also
used in IOP (for chemical dosing
purposes). It has comparatively
less use than Centrifugal Pumps.
CHAPTER 2

20. 15
Pumps in IOP
2.1 Introduction
Pumps are mechanical devise that impart energy to a fluid. Being a hydraulic machine, it
converts mechanical energy to hydraulic energy or pressure energy. Pump is a very common
machine used in several industries (like: thermal power plant, petrochemical plants etc.)
wherever liquid transfer is required.
2.2 Classification of Pumps
Pumps may be classified on the basis of the applications they serve, the materials from which
they are constructed, the liquids they handle, and even their orientation in space. All pumps
may be divided into two major categories: (1) Roto-Dynamic Pumps, in which energy is
continuously added to increase the fluid velocities within the machine to values greater than
those occurring at the discharge so subsequent velocity reduction within or beyond the pump
produces a pressure increase, and (2) Positive Displacement Pumps, in which energy is
periodically added by application of force to one or more movable boundaries of any desired
number of enclosed, fluid-containing volumes, resulting in a direct increase in pressure up to
the value required to move the fluid through valves or ports into the discharge line.
2.2.1 Classification of Roto-Dynamic Pumps
Roto-DynamicPumps
Centrifugal
(Liquid handled: Clean,
clear; dirty, abrasive;
slurries,
Operation: Low head,
high dischage Steady
Flow)
Axial Flow
Stage Basis
Single Stage
Multi Stage
Impeller Basis
Open Impeller
Fixed Pitch
Variable Pitch
Closed Impeller
Mixed Flow,
Radial Flow
Suction Basis
Single Suction
Double Suction
Stage Basis
Self Priming
Non-Priming
Single Stage
Multi Stage
Impeller Basis
Open Impeller
Semi-open Impeller
Closed Impeller
Peripheral
Stage Basis
Single Stage
Multi Stage
Priming Basis
Self Priming
Non-Priming
Special Effect
Jet (Eductor)
Gas Lift
Hydraulic Ram
Electromagnetic

21. 16
2.3 Cavitation
2.3.1 What is Cavitation?
Cavitation is defined as the process of formation of the vapour phase of a liquid when it is
subjected to reduced pressures at constant ambient temperature. Thus, it is the process of
boiling in a liquid as a result of pressure reduction below the vapour pressure of the liquid rather
than heat addition. However, the basic physical and thermodynamic process are same in both
cases.
A liquid is said to cavitate when vapour bubbles form and grow as a consequence of pressure
reduction. When the phase transition results from hydrodynamic pressure changes, a two-phase
flow composed of a liquid and its vapour is called cavitating flow.
2.3.2 Source of Cavitation
A common source of cavitation is the frictional loss incurred in the suction line between the
suction source and a pump. A long suction line, or one with numerous turns or restrictions, can
cause sufficient pressure drop to result in cavitation as the liquid enters the pump. In a
centrifugal pump, the liquid is most likely to vaporize in the eye of the impeller, near the vane
tips. In a reciprocating pump, the liquid is most likely to vaporize in the pumping chamber
between the suction and discharge valves at the face of plunger or piston during the suction
stroke.
PossitiveDisplacementPump
Reciprocating
(Discharge Flow:
Pulsating
Operation: High
Head, low discharge
Use: Dosing &
Pressuring Vessels
[ex. during
hydrotest])
Piston,
Plunger
(Liquid
handled:
Clean and
clear)
Steam - Double
Acting
Simplex
Duplex
Power
Acting
Basis
Single Acting
Double Acting
Structure
Basis
Simplex
Duplex
Triplex
Multiplex
Diaphram
(Liquid
handled:
Clean, clear;
dirty,
abrasive;
slurries)
Operation Basis
Fluid Operated
Mechanically Operated
Structure Basis
Simplex
Multiplex
Rotary
(Liquid handled:
Viscous, non-
abrasive
Operation: High
Head, Low
Dischage, Steady
Flow
Use: Lubricating Oil
Pumps)
Single
Rotor
Vane
Piston
Flexible Member
Peristaltic
Screw
Multiple
Rotor
Gear
Lobe
Circumferential Piston
Screw
2.2.2 Classification of Positive Displacement Pumps

22. 17
2.3.3 Cavitation types and its prevention
 Types of pump cavitation
A. Vaporization cavitation, also called inadequate NPSHA cavitation.
B. Internal recirculation cavitation.
C. Vane passing syndrome cavitation.
D. Air aspiration cavitation.
E. Turbulence cavitation.
A. Pump cavitation due to vaporization
It’s called “classic Cavitation”. According to Bernoulli’s Law, when
velocity goes up, pressure goes down. Centrifugal pump works by
acceleration and imparting velocity to the liquid in the eye of the
impeller. Under the right conditions, the liquid can boil or vaporize
in the eye of the impeller. When this happens we say that the pump
is suffering from vaporization cavitation. This type of cavitation is
also called inadequate NPSHA cavitation. To prevent this type of
cavitation, the NPSHA in the system (the available energy in the
system), must be higher than the NPSHR of the pump (the pump’s
minimum energy requirement).
 To prevent cavitation due to vaporization
 NPSHA > NPSHR (safety margin)
1. Lower the temperature of the liquid (decreasing the temperature of the liquid decreases
the saturation pressure, causing NPSHA to increase).
2. Raise the liquid level in the suction vessel (increases suction pressure).
3. Change the pump.
4. Reduce motor RPM if possible (Reduces NPSHR).
Fig. 2.3.3.A: Cavitation
due to vaporization
Fig. 2.3.2: Source of Cavitation
Source: The Duriron Co. Inc., Pump Engineering Manual, 5th edition, ©1980, Fig. 5.1, page 64

23. 18
5. Increase the diameter of the eye of the impeller.
6. Reduce the head losses by increasing the pipe diameter, reducing the number of elbows,
valves, and fittings in the pipe, and decreasing the length of the pipe (Increases NPSHA).
7. Reduce the flow rate through the pump by throttling a discharge valve (decreases NPSHR).
8. Use an impeller inducer.
9. Use two lower capacity pumps in parallel.
10. Use a booster pump to feed the principal pump.
B. Pump Cavitation by Internal circulation
This is a low flow condition where the discharge flow of the pump
is restricted and the product cannot leave the pump. The liquid is
forced to recirculate from high pressure zones in the pump into low
pressure zones across the impeller. This type of cavitation originates
from two sources. First, the liquid is circulating inside the volute of
the pump at the speed of the motor and it rapidly overheats. Second,
the liquid is forced to pass through tight tolerances at very high
speed the heat and the high velocity cause the liquid to vaporize.
 To prevent pump cavitation due to internal circulation
This condition cannot be corrected on pumps with an enclosed
impeller.
1. Open the restricted discharge valve on the pump.
2. The problem could be a clogged downstream filter.
3. A closed discharge valve.
4. An over-pressurized header.
5. Check valve installed backwards
6. Operating the pump at or close to shutoff head.
C. Pump Cavitation due to vane passing syndrome
The free space between the impeller blade tips and the
cutwater should be 4% (according to Enggcyclopedia) of
the impeller diameter. This type of cavitation is caused
by use of a larger diameter impeller or from re-
metalizing or coating the internal housing of the pump.
For smaller spaces, the liquid velocity between these
spaces becomes very high. This high liquid velocity
leads to low pressure, heating, bubble formation and
hence cavitation. With the pump disassembled the
damage is seen on the blade tips at the OD of the
impeller and just behind the cutwater on the internal
volute wall.
 To prevent pump cavitation due to vane passing
To prevent damage due to such cavitation, free space between the impeller blade tips and the
cutwater should be at least 4% of the impeller diameter. For example, for a 10” impeller, the free
space should be 4% of the impeller diameter between the blade tips and the cutwater. 10” x 0.04
= 0.4”.
D. Pump cavitation due to air aspiration
Air can be drawn into the piping and pump from diverse forms and different points. Air can
enter into the piping when the pump is in vacuum, through following routes:
Fig. 2.3.3.B: Cavitation
by Internal Circulation
Fig. 2.3.3.C: Cavitation due to vane
passing syndrome

24. 19
o Through pump shaft packing.
o Valves stem packing on valves in the suction piping.
o Joint rings on suction piping.
o Flange faces sheet gaskets at pipe joints.
o O-rings and threaded fittings on instrumentation in the suction piping.
o O-rings and other secondary seals on single mechanical seals.
o The faces of single mechanical seals.
o Air can also enter into the pump from bubbles and air pockets in the suction piping.
o Liquids that foam can introduce air into the pump.
 To prevent pump cavitation due to air aspiration
1. Tighten all flange faces and gaskets.
2. Tighten all pump packing rings and all valve stem packing on suction piping.
3. Keep the velocity of the fluid in the suction piping at less than 8 ft. per second. It may be
necessary to increase the diameter of the pipe.
4. Consider using dual mechanical seals with a forced circulation barrier fluid.
E. Pump cavitation due to turbulence
Turbulent flow leads to formation of vortexes in pump suction. Inadequate piping, sharp
elbows, restrictions, filters and strainers in suction line contribute to turbulence. The waterfall
effect in suction vessels is another contributing factor to pump turbulence.
 To prevent pump cavitation due to excess turbulence in suction line
1. Design the pump suction piping and routing to avoid excess turbulence.
2. Take precaution while fixing the pump suction line size to avoid turbulence and have
sufficient NPSHA.
3. Respect the maximum allowable flow limit of the pumps.
2.4 Net Positive Suction Head (NPSH)
2.4.1 What is NPSH?
Local reduction of the static pressure p to the vapour pressure pv
of the liquid causes
vaporization of the liquid and cavitation. Internal pressure drops are due to a) impeller inlet
velocity head and inlet passage loss and b) blade loading and loss within the impeller. In order
to prevent a substantial decrease of impeller pressure rise, the sum of these pressure drops
should not exceed the difference between Pin (inlet pressure) and pv
, the head equivalent of
which is called “net positive suction head” or NPSH:
Pin − pv
ρg
≡ NPSH ⟹ Pin = ρgNPSH + pv
If P1 be the total pressure at the impeller eye then,
P1 − Pin = ∆Pin (Inlet Pressure loss, negligible)
P1 = p1
+ ρ
V1
2
2
+ ρgZe,1 = Total Suction Pressure
Where,
p1
= Absolute pressure at the impeller eye
V1 = Velocity of the liquid at the inlet
Ze,1 = Elevation height (ft. or m) of the inlet or impeller eye
ρ = Density of the liquid.

25. 20
NPSH =
P1 − pv
ρg
=
𝑃1
ρg
−
pv
ρg
= Total Suction head(hs) − vapour head(hv)
2.4.2 Requirement of NPSH
The low pressure at the suction side of a pump can encounter the fluid to start boiling with
reduced efficiency, cavitation, and damage of the pump as a result. Boiling starts when the
pressure in the liquid is reduced to the vapor pressure of the fluid at the actual temperature.
Pump cavitation occurs when the pressure in the pump inlet drops below the vapour pressure
of the liquid. Vapour bubbles form at the inlet of the pump and are moved to the discharge of
the pump where they collapse, often taking small pieces of the pump with them.
 Effect of Cavitation:
o Loud noise often described as a grinding or “marbles” in the pump,
o Loss of capacity (bubbles are now taking up space where liquid should be present),
o Pitting damage to parts as material is removed by the collapsing bubbles.
Noise is a nuisance and lower flows will slow the process, but pitting damage will ultimately
decrease the life of the pump. So, to encounter the cavitation effects and better life of the pump,
NPSH is mandatory.
2.4.3 Difference between NPSHA and NPSHR
The net positive suction head required to prevent cavitation is determined through testing by
the pump manufacturer and depends upon factors including type of impeller inlet, impeller
design, pump flow rate, impeller rotational speed, and the type of liquid being pumped. The
manufacturer typically supplies curves of NPSHR as a function of pump flow rate for a particular
liquid (usually water) in the vendor manual for the pump.
NPSHA is a function of the system and must be calculated. NPSHA must be greater than NPSHR
for the pump system to operate without cavitating. Put it another way, there must be more
suction side pressure available than the pump requires.
 NPSHA:
The NPSH available to a centrifugal pump combines the effect of atmospheric pressure, water
temperature, supply elevation and the dynamics of the suction piping. The following equation
illustrates this relationship. The sum of these components represents the total head available at
the pump suction.
NPSHA = HA ± HZ − HF + HV − HVP
Term Definition Notes
HA
The absolute pressure
on the surface of the
liquid in the supply
tank
o Typically atmospheric pressure (vented supply tank), but can be
different for closed tanks.
o The altitude affects atmospheric pressure.
o Always positive (may be low, but even vacuum vessels are at a
positive absolute pressure).
HZ
The vertical distance
between the surface of
the liquid in the
supply tank and the
centerline of the
pump
o Can be positive when liquid level is above the centerline of the
pump (called static head).
o Can be negative when liquid level is below the centerline of the
pump (called suction lift).
o Always be sure to use the lowest liquid level allowed in the tank.
HF
Friction losses in the
suction piping
o Piping and fittings act as a restriction, working against liquid as
it flows towards the pump inlet.

26. 21
HV
Velocity head at the
pump suction port o Often not included as it’s normally quite small.
HVP
Absolute vapor
pressure of the liquid
at the pumping
temperature
o Must be subtracted in the end to make sure that the inlet
pressure stays above the vapor pressure.
o Remember, as temperature goes up, so does the vapor pressure.
 NPSHR:
The minimum head required at the suction port of the pump to keep the pump from cavitating.
By design, each pump has certain characteristics (both physical and hydraulic) which determine
the amount of energy needed to force the liquid into the impeller eye, ensure that it remains a
liquid (does not cavitate) on its path through the impeller, and cause the amount needed to
accomplish this. The nature of the pump eye, the structure of the impeller vanes, vane diameter,
speed of operation, and where the pump is operating on its curve are just a few of the factors.
The amount of energy needed by a pump is called Net Positive Suction Head Required, or
NPSHR.
2.5 Types of Impeller
A. Impellers are classified according to the major direction of flow in reference to the axis of
rotation. Thus, centrifugal pumps may have the following:
1. Radial-flow impellers
2. Axial-flow impellers
Fig. 2.5.A.1: Radial-Flow Impeller and Radial Flow Centrifugal Pump
Fig. 2.5.A.2: Axial-Flow Impeller and Axial Flow Centrifugal Pump

27. 22
3. Mixed-flow impellers, which combine radial- and axial-flow principles.
B. Impellers are further classified in one of two categories:
1. Single-suction, with a single inlet on one side
2. Double-suction, with liquid flowing to the impeller symmetrically from both sides
C. The mechanical construction of the impellers gives a still further subdivision into
1. Enclosed, with shrouds or side walls enclosing the waterways
2. Open, with no shrouds
3. Semi-open or semi-enclosed
Fig. 2.5.C: Three types of impeller: (left to right) open, semi-closed, and enclosed (shrouded)
Fig. 2.5.B: Single-Suction and Double-Suction Impellers
Fig. 2.5.A.3: Mixed-Flow Impeller and Mixed Flow Centrifugal Pump

28. 23
 Impeller Design
Impellers of pumps are classified based on the number of points that the liquid can enter the
impeller and also on the amount of webbing between the impeller blades. Impellers can be
broadly classified into two different designs: open and closed. The information below describes
these two designs, their respective advantages and disadvantages, and application
considerations.
1. Open Design
Open impellers simply consist of a series of vanes attached to a central "hub" designed to be
fitted to a shaft. By fitting the vane ends very close to the pump casing, the open impeller is able
to prevent large amounts of fluid or gas from recirculating back through the eye.
The table below describes other advantages and disadvantages of open impeller designs.
Advantages Disadvantages
1. Easy maintenance – Efficiency can be
maintained through frequent vane adjustment.
Open design allows for ease of cleaning and
clearing of clogs. Pump need not be
disassembled for adjustment or maintenance.
1. Impeller-to-casing clearance –
tolerances must be manually
adjusted to compensate for heat.
This adjustment must be done at
operating temperature, which
may be hazardous.
2. Less expensive to manufacture and inspect due
to open design.
2. Use of soft materials – the soft
non-sparking materials required
are practical in few applications.
3. Vane alteration (cutting and filing to increase
capacity) is possible and economical.
2. Closed Design
Closed impellers feature two solid plates attached to both sides of the blades. After the impeller
media enters the eye and makes its way through the vanes it is drawn into a nozzle and expelled.
Because closed impellers have no need for vane/casing tolerance consideration, their efficiency
results from the use of wear rings to prevent media from being recirculated back to the eye.
The table below lists advantages and disadvantages of enclosed impellers.
Advantages Disadvantages
1. Increased efficiency 1. Maintenance and inspection is impossible
to perform without disassembly
2. Suitable for volatile fluids and
explosion-prone environments
2. Prone to clogging
3. Compensates for thermal growth 3. Periodic wear ring maintenance is
necessary to maintain efficiency
4. More expensive to manufacture
2.6 Pump Casing
Pump casing is used to convert a part of velocity energy of the liquid to its pressure energy. It
generally covers the impeller which is mounted in the NDE (Non-driving End) side. Pump
casings are designed to accommodate a range of impeller diameters which allows impellers to
be removed, trimmed, and reinstalled in the same pump casing.

29. 24
2.6.1 Function of Casing
The conversion of velocity head into
pressure head occurs in the pump
casing. Figure 2.6.1 shows the how
velocity head decreases while pressure
head increases as the flow moves
through the discharge side of the case.
The conversion process follows the
principle of conservation of energy as
stated by Bernoulli’s law. Since total
amount of energy must remain constant
(assuming not losses or gains), pressure
head must increase as velocity head is
reduced.
The way to reduce velocity is by
increasing the cross-sectional area of
the flow through the process of
diffusion. Simply put, diffusion occurs
when flow area is expanded. The
expansion causes a reduction in velocity
and an accompanying increase in
pressure.
2.6.2 Types of Casing
Casings are generally two types:
1. Volute Casing
Volute casings build a higher head. One of the main purposes of a volute casing is to help
balance the hydraulic pressure on the shaft of the pump. Running volute-style pumps at a lower
capacity than the manufacturer recommends can put lateral stress on the shaft of the pump,
increasing wear-and-tear on the seals and bearings, and on the shaft itself.
2. Circular Casing
Circular casings are used for low head and high capacity. Circular casings have stationary
diffusion vanes surrounding the impeller periphery that convert velocity energy to pressure
energy. Conventionally, the diffusers are applied to multi-stage pumps. The suction and
discharge nozzles are parts of the casing itself.
2.7 Suction Piping
 The important considerations for Suction Piping are:
1. By all means make the pipe as short and straight as possible, particularly if the fluid has
suspended solids which may cause plugging or hang-ups;
2. Make sure there is sufficient pressure at the pump suction (this means check the NPSHA
against the NPSHR);
3. Eliminate potential for air entrapment in the suction piping
o Maintain adequate levels in supply tanks to eliminate vortices from forming and air
entrapment.
o Avoid high pockets in suction piping, which can trap air.
o Keep all pipe and fitting connections tight in suction vacuum conditions to prevent air
from getting into the pump.
Fig. 2.6.1: Velocity vs. Pressure Head of Flow through Pump
Graph shows the relationship between velocity head and
pressure head of flow through the pump. Casing discharge
is designed to convert velocity head into pressure head while
preserving the total amount of head.

30. 25
4. Pipe diameter on suction side should be equal or one size larger than pump inlet.
5. Ensure the piping arrangement does not cause strain on the pump casing.
Pumps should never support the suction or discharge piping. Any stress on the pump casing
by the piping system greatly reduces pump life and performance.
6. Make sure that the stream flow lines are coming in nice and straight at the pump suction.
This generally means having 5 to 10D straight pipe ahead of the pump inlet.
7. Avoid the use of filters at the pump inlet if at all possible. If their maintenance is often
neglected then the pump will suffer from poor performance and perhaps cavitation.
8. Use a 90° or 45° elbow at the pump inlet pipe end. This will allow almost complete drainage
of the tank and is especially useful in the case of fluids that cannot be readily dumped to the
sewers. It also provides additional submergence reducing the risk of vortex formation.
9. Use of Eccentric reducer
Always use an eccentric reducer at the pump suction when a pipe size transition is required.
Put the flat on top when the fluid is coming from below or straight (see next Figure 2.7.3)
and the flat on the bottom when the fluid is coming from the top. This will avoid an air
pocket at the pump suction and allow air to be evacuated.
Fig. 2.7.2: Elbow on suction intake piping
Fig. 2.7.1: Straight run pipe length on suction intake piping
Fig. 2.7.3: Eccentric reducers at the pump suction
(Source: the Pump handbook published by McGraw-Hill)

31. 26
2.8 Mechanical Seal
2.8.1 Introduction
It is very essential to arrest the leakage of fluid through gaps between the casing and the rotating
elements. Generally, gland packing is a useful element for arresting the leakage of fluid. But, in
some situations, packing material is not adequate for sealing the shaft. One common alternative
method for sealing the shaft is with mechanical seals. Mechanical seals consist of two basic
parts, a rotating element attached to the pump shaft and a stationary element attached to the
pump casing. Each of these elements has a highly polished sealing surface. The polished faces
of the rotating and stationary elements come into contact with each other to form a seal that
prevents leakage along the shaft.
2.8.2 Basic Components
Mechanical seals have been developed to address the shortcomings of stuffing box and packing
gland assemblies. The main components are shown in Figure 2.8.2.
Mechanical seal designs are quite varied
but all based on the same general
concept. They do not attempt to seal
directly against the rotating shaft as
does a packing assembly. Rather, a
mechanical seal moves the joint off the
shaft and places it between a pair of
sealing faces, one which rotates with the
shaft and the other which is stationary
with the case. The mechanical seal faces
are oriented perpendicularly to the
shaft axis and held in contact by one or
more springs. Thus, mechanical seal
designs have been able to eliminate the
radial compression required by stuffing
box and packing assemblies.
While the amount of leakage
through a mechanical seal is generally
less than through packing, some is still
required for lubrication. The need for
lubrication exists because the rotating-
to-stationary seal faces would quickly
be destroyed if allowed to run dry.
Mechanical seal designs employ various
means of lubrication. The lubricating
fluid can be gas or liquid.
2.8.3 Types of Mechanical Seal & Applications
A. Classification by design:
A1. Spring design
A1.1. Single Spring, A1.2. Multiple Spring.
A2. Balancing
A2.1. Unbalanced, A2.2. Balanced.
B. Classification by arrangement:
B1. Single Seal
Fig. 2.8.2: Simplified illustration which shows the general
elements comprising mechanical seals.
Dynamic seal occurs between the rotating and fixed seal
faces. Spring maintains contact pressure between the faces.
Variations in design due to type of lubricating fluid and
contacting/non-contacting are not shown.

32. 27
B1.1. Inside, B1.2. Outside
B2. Double Seal
B2.1. Back to Back, B2.2. Tandem
2.8.4 Advantages and Disadvantages of Mechanical Seal
 Advantages:
o Reduced friction and hence power losses.
o Elimination of wear on Shaft or Shaft sleeve.
o Zero or controlled leakage over a long period.
o Relatively insensitive to shaft deflection or end play.
o Can be used for hazardous & toxic fluids.
o Freedom from periodic Maintenance.
 Disadvantages:
o High initial cost.
o Requires services of expert personnel.
o Calls for employment of good flushing methods.
2.8.5 Different Types of Plans
 Mechanical Seal Piping Plans most used in IOP
o Plan 11, Plan 13 & Plan 52
A. Plan-11:
o Seal flush from pump discharge through orifice.
o Default single seal flush plan.
 Why it is used?
1. Seal chamber heat removal.
2. Seal chamber venting on horizontal pumps.
3. Increase seal chamber pressure and fluid vapor margin.
 Applications:
General applications with clean, non-polymerizing fluids.
Fig. 2.8.5.A: Plan – 11

33. 28
 Preventative Maintenance (Source: flowserve.com)
o Use an orifice with a minimum 3 mm (1/8 inch) diameter.
o Calculate flow rates to size orifice for adequate seal chamber flow.
o Increase boiling point margin with proper orifice and throat bushing sizing.
o Flush should be directed over seal faces with piping at 12 O’clock position.
o Typical failure mode is a clogged orifice - check temperatures at pipe ends.
B. Plan-13:
o Recirculation from seal chamber to pump suction through orifice.
o Standard flush plan on vertical pumps.
 Why it is used?
1. Continuous seal chamber venting on vertical pumps.
2. Seal chamber heat removal.
 Applications:
o Vertical pumps.
o Where Seal chamber pressure is greater than suction pressure.
o Moderate temperature fluids with moderate solids.
o Non-polymerizing fluids.
 Preventative Maintenance (Source: flowserve.com)
o Vent piping loop prior to starting vertical pumps.
o Use an orifice with a minimum 3 mm (1/8 inch) diameter.
o Calculate flow rates to size orifice for adequate seal chamber flow.
o Reduce seal chamber pressure with proper orifice and throat bushing sizing.
o Typical failure mode is a clogged orifice - check temperatures at pipe ends.
C. Plan-52:
o Unpressurized buffer fluid circulation through reservoir.
o Fluid is circulated by a pumping ring in the dual seal assembly.
Fig. 2.8.5.B: Plan – 13

34. 29
 Why it is used?
1. Outboard seal acts as a safety backup to the primary seal.
2. Zero to very low process emissions.
3. No process contamination is allowed.
 Applications:
o Used with dual unpressurized seals.
o High vapor pressure fluids, light hydrocarbons.
o Hazardous/toxic fluids.
o Heat transfer fluids.
 Preventative Maintenance (Source: flowserve.com)
o Piping loop must self-vent to vapor recovery/flare system near atmospheric pressure.
o Process vapor pressure is generally greater than reservoir pressure.
o Buffer fluid must be compatible with process leakage.
o Primary seal leakage is indicated by increased vent pressure.
o Reservoir level indicator shows outboard seal leakage.
2.9 Performance Curve of Centrifugal Pumps
Generally, manufactures provide the
head-discharge curve which is called
the characteristics curve of the
pump. The highest point of the
efficiency curve is called Best
Efficiency Point (BEP). The
operators have the system curve
depending upon the usage of the
pump. The intersecting point of the
H-Q curve and the system curve is
called operating point as shown in
the diagram.
Fig. 2.8.5.C: Plan – 52

35. 30
2.10 Pumps in IOP
Centrifugal pumps are mostly used in IOP. There are also application of reciprocating pumps in
IOP in specified places. Here some of the pumps are described in details.
 Pump areas in IOP
The pump areas in IOP are: 22, 23, 25, 33, 41, 42, 43, 45, 46, and 47.
Among these areas, four pumps are selected for detailed description.
1. 41-P-10B:
o Service: C3/C4 Mixed LPG/Propylene Unloading Pump.
o Pump Type: Vertical Barrel type Multi Stage Centrifugal Pump
o Capacity (m3
/hr.): 15 (Minimum), 45 (Normal), 50 (Maximum), 60 (at B.E.P.)
o Coupling Type: Metaflex Coupling.
o Mechanical Seal Type: Durametallic, Tandem Seal.
o Plans installed:
1. Plan-13: Recirculation from Mechanical seal through orifice to pump suction.
2. Plan-52: Circulation to Outboard seal through container.
3. Plan-61: Vent/Inlet and drain plugged.
o Differential Head (m): 80 (Butane), 90 (Propane), 85 (Propylene)
o Casing Mounting: Vertical Barrel
o Performance:

36. 31
o Diagram:
2. 42-P-002 A/B/C:
o Service: HP Ethylene Pump.
o Pump Type: Vertical Barrel type Multi Stage Centrifugal Pump
o Capacity (m3
/hr.): 80 (at B.E.P.)
o Coupling Type: Metaflex Coupling (Triveni Flexibox TSKS-0060-0037-1800)
o Mechanical Seal Type: Tandem Type (Make: Sealol)
o Plans installed:
1. Plan-13: Recirculation from Mechanical seal through orifice to pump suction.
2. Plan-52: Circulation to Outboard seal through container.
o Maximum Head Rated (m): 615
o Speed: 2960 rpm
o Casing Mounting: Vertical Barrel
o No. of stages: 14

37. 32
o Performance: Efficiency 70%

38. 33
o Diagram:

39. 34
3. 23-P-009 A/B:
o Service: ACF Backwash Water Pump.
o Pump Type: Single volute foot casing type Centrifugal Pump
o Capacity (m3
/hr.): 330 (at B.E.P.)
o Coupling Type: Flexible Spacer.
o Packing Type: Gland Packing.
o Maximum Head Rated (m): 40
o Speed (rpm) : 1470
o Casing Mounting: Foot Casing

40. 35
o Performance: Efficiency – 77.50%

41. 36
o Diagram:
4. 25-P-002G
o Service: Cooling Water Circulation pump.
o Pump Type: Double Suction type Horizontal Centrifugal Pump (Double Volute, simple
supported)
o Capacity (m3
/hr.): 4500 (at B.E.P.)
o Coupling Type: Flexi-metallic Spacer.
o Packing Type: Gland Packing.
o Maximum Head Rated (m): 72
o Speed (rpm) : 992
o Casing Mounting: Foot Casing

42. 37
o Performance: Efficiency – 93.0%

43. 38
o Diagram:
****

44. 39
REFERENCES
A Report on Pumps in IOP
R E S O U R C E S
1. Pump Handbook of McGraw-Hill Edited by
Igor J. Karassik, Joseph P. Messina, Paul
Cooper, and Charles C. Heald.
2. Centrifugal Pumps: Overview of Design,
Operation and Malfunctions by D. Craig
Sever and Charles T. Hatch (Bently Nevada
Corporation).
3. Enggcyclopedia (Industrial Wiki:
https://www.myodesie.com).
4. Pumps & Systems
(www.pumpsandsystems.com).
5. Engineering Toolbox
(http://www.engineeringtoolbox.com).
6. PowerPoint presentation of IOP DETAILS.
7. IOP Pumps Manual Drawings of area: 41, 42,
23 & 25.
8. IOP Tanks Manual Drawings (41-T-001
A/B/C/D).
Summer Report
Haldia Petrochemicals Limited