Boiler Operation

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INSTRUCTOR:
ROBERT A. MCLAUGHLIN
ZAILI THEO ZHAO
1
INTRODUCE & PUMPS
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POWER
EQUIPMENT
POWER EQUIPMENT
EG234
 Lecture/A - Power Equipment Lab
 Credits: 2.00
 An introduction to marine and stationary power
plant systems and equipment through study,
inspection, and maintenance applications.
course supports the marine license program
requirements to meet the Standards for Training,
Certification and Watchkeeping (STCW).
 The course may have embedded assessment
requirements that must be completed in addition to
the class requirements.
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
 The
2
TEXTBOOKS & REFERENCES
TEXTBOOKS

Principles of Naval Engineering.



NAVPERS 10788-B
NAVEDTRA 12960. U.S. Navy, 1992.
Power Equipment Lab Project Manual,


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
Seventh Edition, 2002.
REFERENCES:

Control Valves & Actuators.



Modern Marine Engineers Manual.



Instrument Society of America:
Industrial Training Corp. 1989.
Hunt, Everett C.
Vol. 1, Third Edition, 1999.
Control Valve Handbook:


Fisher Controls Co.
Second Edition, 1977.
3
OBJECTIVE
Student will be exposed to
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


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
the theory of auxiliary power equipment systems used
in maritime & power plants.
making accurate system drawing of components.
the importance of measurement principles and quality
repair standards.
basic safety concerns and lockout/tagout procedures
typical in industry.
Students will demonstrate




an understanding the auxiliary power systems.
The ability to create accurate system drawings.
Accurate measurement standards and basic repair
techniques.
understanding of basic safety procedures.
4
TOPICS
Week 1: Fluid Pumps


Multistage Compressor, Internals & Demonstration
Week 6: Automated Valves & Regulators


Valves, Packing & Steam Traps
Week 5: Air Compressors & Air Handling Systems


Temperature & Fluid Flow Measurements
Week 4: Piping, Valves, Fittings and Steam Traps


Tubular/Disc Purifiers
Week 3: Measurement Temperature, Fluid Flow and
Level


Centrifugal, Recip. & Gear, Type Pumps
Week 2: Lube Oil Purifications & L.O. Management


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
Air Operated Control Valves & Self-contained Reducers
Week 7: Heat Exchangers, Purpose, Mediums, Flow

Heat Transfer/Exchanger Demo
5
TOPICS (CONT.)
Week 8: Distilling Plants

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Auxiliary Turbine Operations
Week 13: High Pressure Fittings

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Isolation & Reactivation
Week 12: Auxiliary Turbines & Controls

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Shaft Seal Assembly
Week 11: Tagout & Safety Procedures

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Shaft Alignment Model Training
Week 10: Shaft Seal Systems Gland Seals, Mechanical
Seals & Packing Glands - Industrial Packing,

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Desalination Equip. & Reverse Osmosis Demonstration
Week 9: Machinery Alignment & Couplings

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Boiler Gage Glass, Replacement/Torque Procedures
Week 14: Industry Presentation Guest Lecture

Quality Assurance
6
EVALUATION & EXAM
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
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Assignments and Class Participation 25%
Quizzes (6)
50%
Final Comprehensive Exam
25%
There will be six quizzes given throughout the
semester.
An exam will be given every other week throughout
the semester, and there will also be a comprehensive
final exam of the course at the end of the semester.
An excused absence from a quiz will require the quiz
to be made up within one week of the original
schedule.
Failure to complete the makeup will result in a zero
for the missed quiz.
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
7
WEEK 1
PUMP LEARNING OBJECTIVES
Develop an understanding of how pumps function
 Identify various pump types, applications and
limitations
 Define pumping principles and terms common to
pumps, such as: pressure head, Static head,
velocity head and friction head
 Introduce the formula for determining the
capacity and discharge pressure of a
reciprocating pump, PLAN = PLAN
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
8
PUMP FUNCTION

Pumps are used to add energy to liquids to produce
flow or increase pressure.
They function to
 Circulate liquids and with most



Fuel delivery systems
Transfer – move liquids from one area to another


Cooling systems
Heating systems
Supply
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Fuel oil transfer
Pressurize systems
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Domestic water systems
Hydraulic systems
9
FORCE- PRESSURE –AREA
RELATIONSHIPS
is defined as force
per unit area
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 Pressure
for us in this class we will use
pounds per square inch (psi.
 How much pressure is there at
the bottom of a 33 ft column of
water? (p = h)

62.4

lb
in 2
lb

33
ft
/
144
(
)

14
.
33
ft 3
ft
in 2
.433 psi per ft for water.
10
FORCE- PRESSURE –AREA
RELATIONSHIPS

principle
pressure is transmitted equally and undiminished in all
directions of a contained system.
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 Pascal’s
11
SUCTION AND DISCHARGE
All pumps move fluid(water, oil, molten metal,
sludge) from one place to another by:
 Pushing
 Pulling
 Throwing
 Squeezing or some combination of all of these
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
12
POWER END AND FLUID END
All pumps have:
 A power end
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
Pistons on reciprocating pumps
 Motors on centrifugal pumps
 Electric / Hydraulic / Air
 Steam turbine or internal combustion engine


Fluid end or the pumping end
Pumps develop no energy of their own.
 They transform energy from some external
source to potential and kinetic energy.
 We measure the input source of power in
horsepower (HP)

13
KINETIC PUMP
The major types of pumps are




kinetic(Centrifugal),
positive displacement, and
eductors:
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
Kinetic pump (centrifugal)
which uses a spinning rotor (impeller or propeller) to
increase kinetic energy or velocity head and pressure of
the pumped fluid and pressure of the pumped liquid.
 Centrifugal pumps may be operated with the discharge
closed; however, the friction of the fluid churning within
the casing will generate heat.




It is not a good idea to operate for long periods of time with the
discharge closed.
Systems, like boiler feedwater systems, which have regulators
that may limit or stop flow for short periods of time, will have
recirculation lines.
A recirculation line connects the pump discharge to the suction
source, and should open when the discharge flow decreases.
14
TYPES OF CENTRIFUGAL PUMPS
Volute Pump
In the volute pump, which is also the pump casing,
the impeller discharges into a volute, which is a
gradually widening spiral channel in the pump
casing.
 The volute converts the liquid velocity created by the
impeller to pressure.

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15
TYPES OF CENTRIFUGAL PUMPS
Diffuser Pump
In the diffuser pump the liquid leaving the impeller
is first slowed by the stationary diffuser ring that
surrounds the impeller.
 The diffuser consists of gradually widening passages
through which the liquid dumps into the volute of the
pump.
 Since both the diffuser and the volute reduce the
velocity of the liquid, there is almost a complete
conversion of the kinetic energy (velocity head) to
potential energy (pressure)
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16
IMPELLERS
The impellers spin at a high rate of speed and
must be carefully machined and balance to avoid
vibration.
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
Closed impellers have side walls or shrouds on both
sides of the vanes.
 A semi-closed impeller has a wall on one side of the
vanes; the other side is open
 An open impeller has no side walls, the vanes are
attached directly to the hub.

Hub- a solid center area that has a hole through it.
 The pump shaft extends through the hub

17
EYE OF THE IMPELLER
The eye is the area the liquid enters into the
impeller.
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
Liquid is led to the eye through internal passages in
the pump casing
 An impeller can have a single suction eye, or it can
have two suction eyes; one on each side of the
impeller.

A single eye impeller creates thrust axially in a direction
opposite of the liquid entering the eye.
 In the double suction impeller the thrust is counter acted
 Water enters the eye in an axial direction, and leaves the
impeller in a radial direction.

18
MULTY STAGE, SHAFT SEAL &
High pressures, centrifugal pumps can have
multiple impellers mounted on one shaft.


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
The discharge from the first stage enters the second
stage impeller eye.
The area where the shaft passes through the
casing must be sealed.

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Packing or with mechanical seals.
A packed pump will have a lantern ring or seal cage
installed.
The seal cage is a place where discharge pressure liquid
can be introduced into the stuffing box to lubricate, seal
and cool the packing.
19
CAPACITY
capacity is expressed as volumetric
flow rate & discharge pressure

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 Pump
The capacity of a centrifugal pump can be
increased by doing one of two things
Increase the speed of the pump
 Increase the size of the impeller

20
POSITIVE DISPLACEMENT
PUMP

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A movable element forces liquid through the
pumps casing.
 They never stop pushing the liquids.
 All positive displacement pumps must have a
protection device (relief valves) on the
discharge end, and should never be operated
with the discharge closed.

There are several types of positive displacement
pumps:
Gear
 Lobe
 Vane
 Screw

21
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22
RECIPROCATING PUMPS
A positive displacement pump
Piston reciprocates back and forth inside a cylinder.
 The liquid piston is driven by power piston.

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Classed as:

Single-acting or double-acting.


Simplex or duplex.

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A simplex pump has only single pumping cylinder and a duplex
pump has two.
High or low pressure.


A single acting pump pumps only on one side of the liquid
piston; whereas a double acting pumps on both sides. The
pump shown above is a double acting pump.
When the power piston is larger than the liquid piston, the
pump is high pressure.
Vertical or Horizontal
23
RECIPROCATING PUMP
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A reciprocating pump moves
water or other liquid by a
plunger or piston that
reciprocates (travel back and
forth) inside a cylinder.
 Reciprocating pumps are
positive-displacement pumps;
each stroke displaces a definite
quantity of liquid, regardless of
the resistance against which the
pump is operating.

24
RECIPROCATING PUMP

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classified as follows:
Direct-acting or indirectacting
Simplex (single) or duplex
(double)
Single-acting or double-acting
High-pressure or low-pressure
Vertical or horizontal
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 Usually
25
RECIPROCATING PUMPS
A full description of a reciprocating pump includes
three numbers followed by it classification.

For example, a pump is a Duplex, double acting, 8  6  12.

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
Two pumping cylinders,
which pump on both sides of the cylinders.
The power pistons are 8” in diameter.
The liquid pistons are 6” in diameter,
The pump has a 12 in stroke.
Formulas for calculating the capacity and discharge
pressure of a reciprocating pump is
PLAN(power end) = PLAN(pump end)
P = Inlet pressure on the power piston and the discharge
pressure on the discharge end
 L = length of the pump stroke.
 A = the areas of the cylinders, power end, and pump end.
 N = number of strokes per min.

26
RECIPROCATING PUMPS
can be determined with the
formula:
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 Capacity
Capacity= LAN / (321 in3 per gal) = GPM
The liquid end piston area is used to determine the
pump capacity
 Pump discharge pressure can be determined with
this formula:

P(Liquid)= P(power) × A(power)/ A(Liquid)
27
PUMP TERMS
Pump capacity
The capacity of a pump is the amount of liquid the
pump can handle in a given period of time.
 It is usually expressed in GPM delivered at a specific
pressure.
 What happens to the pump capacity as the viscosity
of the fluid increases? Increase or decrease?

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
28
PUMP TERMS
Total pump head
 Head is the vertical
distance between the two
liquid levels in a pumping
system.
 Total pump head is the
sum of the suction lift and
the discharge head.
 The pump may be
installed at, above, or
below the surface of the
source supply.


When the pump is below the
suction liquid level, it has a
static suction pressure.
When it is above, it has a static
suction lift.
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
29
PUMP TERMS
Total pump head
 The vertical distance from
the centerline of the pump
to the liquid level on the
discharge is known as the
static discharge head.
 Friction head- In addition to
the head pressures, there is
always a friction loss
associated with the system.
 The energy required to
overcome this loss
manifests itself as thermal
energy, which remains in
the liquid.
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
30
PUMP TERMS
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
Velocity head
The head pressure required to impart velocity to a fluid.
2
 Formula Hv = V /2g Hv is the velocity head in feet

 Net
Positive Suction Head (NPSH)
It is the head necessary needed to overcome the
friction and flow losses in a pump’s suction.
 The minimum suction head will be supplied by the
pump manufacturer.
 If a pump is operated below the NPSH, cavitation can
occur.

31
CAVITATION

Cavitation is the formation and subsequent collapse of
vapor-filled cavities or bubbles in the pumped liquid.
Cavitation creates noise and vibration in a pump, and if
it is allowed to continue it will cause pitting on the
internal metal surfaces of the pump.
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
32
PUMP TERMS
power required to drive a pump is a
function of the pump capacity and the total
head against which the pump operates.
Measured in HP, how much horse power is
necessary to deliver the required liquid
against the pumping head.
 Bernoulli’s Theorem- A form of the general
energy equation.
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 The
Energy in = energy out
 There is not a direct correlation between in and out
energy because of efficiency

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33
Ejecter
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34
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35
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THANK YOU
36
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