Welcome to Process Operations for Diploma students

Zin Eddine Dadach
Chemical Engineering Department
Higher Colleges of Technology
2014-2015


Chemical Engineering
Chemical engineering
essentially deals with the
engineering of chemicals,
energy and the processes
that create and/or convert
them.
Modern chemical
engineers are concerned
with processes that convert
raw materials or (cheap)
chemicals into more useful
or valuable forms.


Job opportunities for Chemical
Engineers
Chemical engineering are employed across a huge variety
of sector including:
Chemical and allied products
Pharmaceuticals
Energy
Water
Food & drink
Oil & gas
Process plants & equipment
Biotechnology
Business and management
Consultancy


Chemical engineer duties
Chemical engineers utilize
mass, momentum, and
energy transfer along with
thermodynamics and
chemical kinetics to
analyze and improve on
"unit operations in a
chemical plant."

Introduces basic chemical engineering unit operations.
Three main areas of unit operations are covered: Fluid
flow, heat transfer and mass transfer.
The principles of operation of major equipment and
machinery often found in the chemical process
industries are presented.
Fundamental engineering calculations are introduced,
and laboratory work is used to reinforce the
understanding of certain chemical engineering
phenomena.
Objective of the course

 CLO 1- Explain the meaning of unit operations and identify
the various unit operations found in the plant
 CLO 2- Explain the importance of piping systems, fittings
and devices used for metering of fluids
 CLO 3- Describe the various types of machinery to move
fluids
 CLO 4- Discuss the principles of operation of fired heaters
and heat exchange equipment
 CLO 5- Discuss the principles of separation processes and
their equipment
LEARNING
OUTCOMES


 Introduction to the course.
 Many examples are to be given to the students as well as
relevant articles on the subject.
SO1: Explain the meaning of unit operations
SO2: List the unit operations most likely found in the plant
If the schedule permits, a site visit to a chemical industry will
complement this learning outcome
L.O #1


An oil refinery or petroleum refinery is
an industrial process plant where crude
oil is processed and refined into more
useful products such as petroleum
naphtha, gasoline, diesel fuel, asphalt
base, heating oil, kerosene and liquefied
petroleum gas.
OBJECTIVE OF OIL REFINERY


Petroleum products are grouped into three categories: light
distillates, middle distillates and heavy distillates.
 LIGHT DISTILLATES:
Liquefied petroleum gas (LPG), Gasoline (also known as petrol,
Naphtha
 MIDDLE DISTILLATES:
Kerosene and related jet aircraft fuels, Diesel fuel
 HEAVY DISTILLATES
Fuel oils, Lubricating oils, Paraffin wax, Asphalt and tar,
Petroleum coke
MAJOR PRODUCTS


LISTEN...LEARN...THINK...
GROW
11
MAIN REFINERY PRODUCTS


Pretreatment: Desalting before entering
the refinery to avoid corrosion problems:
 Preheating of crude oil for separation by
distillation
Separation of crude oil into fractions by
atmospheric and vacuum distillation.
Chemical transformation
COMMON PROCESS UNITS
FOUND IN A REFINERY

Desalter to remove the
impurities : salt, water, solids, ....


 A desalter is a process unit in an oil refinery that removes salt from
the crude oil. The salt is dissolved in the water in the crude oil, not in
the crude oil itself.
 The desalting is usually the first process in crude oil refining. The salt
content after the desalter is usually measured in PTB - pounds of salt
per thousand barrels of crude oil.
 Usually desalting is necessary only when the salt content of a crude
oil is greater than 10 lb/ 1000bbl (expressed as NaCl)
 But now almost all crude oils are desalted to increase the efficiency
of the refineries LISTEN...LEARN...THINK...GROW 14
CRUDE OIL DESALTING


LISTEN...LEARN...THINK...GROW 15
Electrostatic De-salter

 Following the desalter, the crude oil is further heated by exchanging heat
with some of the hot, distilled fractions and other streams. It is then heated
in a fuel-fired furnace (fired heater) to a temperature of about 398 °C and
routed into the bottom of the first distillation unit.
LISTEN...LEARN...THINK...GROW 17
PREHEATING CRUDE OIL


FURNACE
One of the major energy
demands within
refineries comes from the
need to heat the crude
feedstock upstream of
the crude distillation
column to obtain the
desired flash and
distillation yields.


STEP III: ATMOSPHERIC AND
VACCUM DISTILLATION
 The crude atmospheric and vacuum distillations are the first major
processing units in any refinery.
 They are used to separate the crude oils into fractions according to
boiling point so that each of the processing units following will have
feedstock that meet their particular specifications.
 Higher efficiencies and lower costs are achieved if the crude oil
separation is accomplished in two steps:
 First by fractionating the total crude oil at essentially atmospheric
pressure;
 Then by feeding the high-boiling bottoms fraction (topped or
atmospheric reduced crude) from the atmospheric still to a second
fractionator operated at a high vacuum


GROW
21
OVERVIEW OF THE TWO
DISTILLATION UNITS


GROW
22
Boiling points & Number of
Carbons of Products


AFTER DISTILLATION:
CHEMICAL PROCESSES


Chemical transformation of
crude oil fractions


Distillation in Distillation
columns
Cracking reactions in chemical
reactors
Video:
Processes in oil Refinery


 Unit Operations are the basic physical
operations of chemical engineering in a
chemical process plant, that is, distillation,
fluid transport, heat and mass transfer,
evaporation, extraction, drying, crystallization,
filtration, mixing, size separation, crushing and
grinding, and conveying
What is unit operation?

 1.Fluid flow processes, including fluids transportation,
filtration, and solids fluidization.
 2.Heat transfer processes, including evaporation,
condensation, and heat exchange.
 3.Mass transfer processes, including gas absorption,
distillation, extraction, adsorption, and drying.
 4.Thermodynamic processes, including gas liquefaction, and
refrigeration.
 5.Mechanical processes, including solids transportation,
crushing and pulverization, and screening and sieving.
Chemical engineering unit
operations consist of five classes:


1. Fluid Flow Process:
Fluid Transportation
Pipeline transport is
the transportation of
goods through a
pipe. Liquids and
gases are transported
in pipelines and any
chemically stable
substance can be sent
through a pipeline


2.Heat transfer processes
Heat Exchanger
A heat exchanger is a
piece of equipment built
for efficient heat transfer
from one medium to
another. The media may
be separated by a solid
wall to prevent mixing
or they may be in direct
contact


3.Mass Transfer Processes
Distillation
 Distillation is a process of
separating the component
substances from a liquid mixture
by selective vaporization and
condensation.
 Distillation may result in
essentially complete separation
(nearly pure components), or it
may be a partial separation that
increases the concentration of
selected components of the
mixture.


4.Thermodynamic processes
Gas Liquefaction
 Liquefaction is used for
analyzing the fundamental
properties of gas molecules
(intermolecular forces), for
storage of gases, for example:
LPG, LNG
 At atmospheric pressure, very
low temperatures are required.
The natural gas is condensed
into a liquid at approximately
−162 °C (−260 °F).


5. Mechanical processes
Crushing
 Crushers may be used to
reduce the size, or change the
form, of waste materials so
they can be more easily
disposed of or recycled, or to
reduce the size of a solid mix
of raw materials (as in rock
ore), so that pieces of different
composition can be
differentiated.

Fluids are materials that can flow, and
they include both gases and liquids.


What is Mass?
Mass is the amount of
matter in a given
object.
Anything made up of
matter has mass.
SI Unit of mass is (kg)


Mass
(“weight”)*
milligram mg 1000 mg = 1 g
gram g
kilogram kg 1 kg = 1000 g
metric ton t 1 t = 1000 kg
Common Units of mass


 Mole is a unit of measurement used in chemistry to express
amounts of a chemical substance, defined as the amount of any
substance that contains as many elementary entities
 Molecular mass or molecular weight refers to the mass of a
molecule. It is calculated as the sum of the mass of each
constituent atom multiplied by the number of atoms of that
element in the molecular formula
 𝑀𝑜𝑙𝑒 =
𝑚𝑎𝑠𝑠
𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑤𝑒𝑖𝑔ℎ𝑡
Mole & Molecular weight


Hydrogen (H2) has two hydrogen atoms.
The atomic mass or molecular weight of hydrogen is 2.
 The molecular weight of methane, molecular formula
CH4, is calculated as follows.
EXAMPLES
atomic mass total mass
C 12 12
H 1 4
CH4 16 Molecular weight


 1) How many moles of hydrogen (H2) have a mass of 8g
 2) What is the molecular weight of water ( H2O) if 2 moles
contain 36 grams.
 3) What is the total mass of 1 mole of ethane C2H6
Class activity


What is Weight ?
Weight is a force we
get as we press against
other objects. You
press against a scale to
measure your weight.
What pulls you against
the scale?
SI Unit of weight is
Newton


Mass and Weight

Weight= Mass x gravity
W= m. g


What is Volume ?
 Volume is the quantity of
three-dimensional space
enclosed by some closed
boundary.
 For example, the space that a
substance (solid, liquid, gas,
or plasma).
 A measuring cup can be used
to measure volumes of
liquids.
 SI unit of volume is m3


Volume milliliter (mL) 1000 mL = 1 L
Cubic centimeter (cm³) 1 cm³ = 1 mL
Liter (L) 1000 L = 1 m³
Cubic meter (m³)
Common Units of Volume


Prefix Symbol Factor Numerically Name
giga G 109 1 000 000 000 billion
mega M 106 1 000 000 million
kilo k 103 1 000 thousand
centi c 10-2 0.01 hundredth
milli m 10-3 0.001 thousandth
micro μ 10-6 0.000 001 millionth
nano n 10-9 0.000 000 001 billionth
Prefixes for Units

47
Mass Density
Volume
Mass

SI Unit of Mass Density: kg/m3
DEFINITION OF MASS DENSITY
The mass density (Rho) is the mass m of a substance divided
by its volume V:


48
Solids have
highest density
Aluminum 2 700
Brass 8 470
Concrete 2 200
Copper 8 890
Diamond 3 520
Gold 19 300
Ice 917
Iron (steel) 7 860
Lead 11300
Quartz 2 660
Silver 10 500
Wood (yellow pine) 550
Mass Densities of Common Substances
(Unit: kg/m3)

49
Liquids have
intermediate
densities
Blood (whole,
37°C)
1060
Ethyl alcohol 806
Mercury 13600
Oil (hydraulic) 800
Water (4 °C) 1 × 103
Gases have the smallest
densities
Air 1.29
Carbon dioxide 1.98
Helium 0.179
Hydrogen 0.0899
Nitrogen 1.25
Oxygen 1.43
.


 1) A solid has a density of 917 kg/m3. What will be its mass in
a container of 3 m3 ?
 2) Water occupies a volume of 5 m3. What is the mass
 An unknown gas has a mass of 6.45 kg and occupies a volume
of 5 m3. What is the density? What is this gas?
Class activity


 If we know the total mass of the mixture and the
mass of each component, we can calculate the total
mass by dividing the mass of each component by the
total mass.
 The total mass composition should be equal to 1
Mass composition
Components Mass (grams) Mass composition
Water 15 15/65= 0.23
Gasoline 40 40/65= 0.61
Salt 10 10/65= 0.16
Total 65 1.00


Find the composition of a mixture containing
1ograms of sugar, 20 grams of water and 5 grams of
coffee.
Class activity


54
Piping Systems
Introduction
Basis for Design
Piping Codes and Standards
Design of Process Piping Systems
Joints and Fittings
Valves


55
Parts Of Piping Systems
Piping Systems include:
Pipe
Flanges
Fittings
Bolting
Gaskets
Valves
Hangers and supports
Insulations, coverings, coatings


“Piping systems are like arteries and veins. They carry the
lifeblood of modern civilization.”
56
Piping Systems


57
Piping Systems :Safety First
Primary Design Consideration is Safety
Evaluate Process Conditions
 Temperature
 Pressure
 Chemical compatibility/Corrosion allowances
 Vibration, flexing, bending
 Expansion/Contraction due to temperature change
 Environmental conditions
Evaluate the Effects of a Leak
Evaluate Performance in a Fire Situation


58
Piping Systems : Special Requirements
Evaluate any Special Requirements
 Sanitary requirements – “Cleanability”
 Serviceability – ease of maintenance of equipment
 Possible contamination of process fluid by piping materials,
sealants, or gasketing
 Earthquake, Hurricane, Lightening, Permafrost
Lowest Cost over the Lifetime


59
CM4120
Unit Operations Lab
Codes and Standards for Piping Systems
Codes and Standards simplify design, manufacturing, installation
process
Standards – provide design criteria for components
 standard sizes for pipe
 dimensions for fittings or valves
Codes – specific design/fabrication methodologies
 Incorporated into local/regional statute
 It’s the LAW


60
Standards for Piping Systems
ASME Boiler and Pressure Vessel Code
ASME B31: Code for Pressure Piping
ANSI Standards – dimensions for valves, piping,
fittings, nuts/washers, etc.
ASTM Standards for piping and tube
API – Specs for pipe and pipelines
AWS, ASHRAE, NFPA, PPI, UL, etc.


61
ASME B31 is the applicable standard for design
of most piping systems in chemical plants
B31.1 – Power plant boilers
B31.3 – Chemical plant and refinery piping
B31.4 – Liquid petroleum transport
B31.7 – Nuclear power plant radioactive
fluids


62
ASME B31.3 – Chemical Plant and Refinery Piping Code
Includes:
Process piping in chemical and refinery plants
Process piping in pharmaceutical and food processing
Process piping in textile and paper plants
Boiler piping


63
ASME B31.3 covers:
Materials and design
Fabrication
Erection and assembly
Support
Examination, inspection, and testing
Web reference: www.piping-toolbox.com


64
Piping Systems : Standard Pipe Sizes
Diameters are “Nominal”
 Sizes 12” and less, nominal size < OD
 Sizes 14” and over, nominal size = OD
Wall thickness inferred thru “Schedule”
 Schedule = P/S * 1000
 Defined Schedules:
5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160


65
Piping Systems: Standard Tubing Sizes
Steel tubing:
 Diameters are Actual OD
 Wall thickness is specified
Refrigeration Tubing
 Single wall thickness available for each size
 Actual OD
Copper Tubing – Nominal sizes
 Type K, L, M


66
Piping Systems Materials – Metallic piping
Carbon and low alloy steel
 Ductile
 Inexpensive and available
 Easy to machine, weld, cut
 Some drawbacks


67
Alloy Steels including “Stainless Steels”
 Good corrosion resistance
 More difficult to machine, weld, cut
 Some drawbacks


68
Nickel, Titanium, Copper, etc.
 Copper is used in residential and commercial applications
and is widely available
 Other materials are expensive and difficult to machine,
weld, join
 Some incompatibilities with each


69
Piping Systems Materials – Non-Metallic piping
Thermoplastics
 Wide range of chemical compatibility
 Light weight
 Easily cut and joined
 Low temperature limits
 Need extra supports


70
Piping Systems Materials – Non-Metallic piping
Fiberglass Reinforced Pipe
 Wide range of chemical compatibility
 Easily cut and joined
 Wider temperature limits than thermoplastics
 Thermal expansion similar to carbon steel
 Similar structural performance as carbon steel


71
Piping Systems: Materials – Others
Glass
Concrete
Lined or coated
 Glass
 Rubber
 Cement
 Teflon
 Zinc (galvanized pipe)
Double Containment piping systems


72
Piping Systems : Piping Insulation
Prevent heat loss/ gain
Prevent condensation – below ambient
Personnel protection – over 50oC
Freeze protection – outdoor cold climates
Fire protection
Noise control

73
Piping Systems : Insulation
Fiberglass Insulation w/ Asbestos plastered
fitting coverings

74
Piping Systems Insulation
Metal Jacketed
insulation
covering


75
Piping Systems : Heat Tracing
Prevents flow problems in cold climates
 Freeze protection
 Loss of flow due to viscosity increase
Prevent condensation in vapor lines
Methods
 Electric
 Hot Fluids


76
Piping Systems : Piping Supports
Prevent strain at connections
Must allow for expansion/contraction
Design for wind/snow and
ice/earthquake
Clearance for plant traffic and equipment

77
Piping Systems : Results of inadequate
support

78
Results of inadequate support:
May, 1974 – Leaking reactor removed from train of reactors and
temporarily replaced with a section of pipe
June, 1974 – Supports collapse, pipe breaks
28 dead, 89 injured, 1800 houses damaged, 160 shops and
factories damaged, large crater where plant stood


79
CM4120
Unit Operations Lab
Piping Systems
Select in-line components
Determine insulation, coverings, coatings
Design and locate supports and hangers


80
Piping Systems : Pipe Joints
Threaded
Welded
Soldered/ Brazed
Glued
Compression
Bell and spigot
Upset or expanded

81
Piping Systems : Threaded joints

82
Piping Systems : Soldered joints

83
Piping Systems : Welded joints

84
Piping Systems : Compression joints

85
Piping Systems: Mechanical joints
shown on glass drain piping system


86
Piping Systems: Pipe Fittings
 Forged
 Cast
 Malleable Iron
Pressure/Temperature Rated by “Class”
 125, 250, or 2000, 3000, etc.
 Need a look-up table to determine max. allowable P for the design
temperature

87
Fittings for joining 2
sections of pipe:
Coupling
Reducing Coupling
Union
Flange

88
Piping Systems
Fittings for changing
directions in pipe:
45o Ell
90o Ell
Street Ell

89
Piping Systems
Fittings for adding a
branch in a run of
piping:
Tee
Cross

90
Piping Systems
Fittings for blocking
the end of a run of
piping:
Pipe plug
Pipe cap
Blind Flange

91
Piping Systems
Misc. pipe fittings:
Nipple
Reducing bushing

92
Piping Systems: Valves
Gate Valve:
Used to block flow
(on/off service)
Sliding “gate”
on knife-gate
valve

93
Piping Systems :
Globe Valve
Globe Valve:
Used to regulate
flow
Cut-away shows
stem seal
plug
and seat

94
Piping Systems : Ball
Valve
Ball Valve:
Typically used as
block valve
“Quarter-turn”
valve
Cut-away shows
ball and seat

95
Piping Systems:
Butterfly valve
Butterfly Valve:
Can be used for
flow control or
on/off
Valve actuator/
positioner for
accurate flow
control

96
Piping Systems: Check
Valve
Check Valves:
Used to prevent
backflow
Piston check
Swing check


Fluid Flow
• Mass flow rate: Av (kg/s)
• Continuity: 1A1 v1 = 2A2 v2
i.e., mass flow rate the same everywhere
e.g., flow of river
A1 1 A2 2v1 v2


Paul E. Tippens
Fluid Motion
 The lower falls at
Yellowstone National Park:
the water at the top of the
falls passes through a narrow
slot, causing the velocity to
increase at that point.


Fluids in Motion
All fluids are assumed in this
treatment to exhibit streamline
flow.
• Streamline flow is the motion of a fluid in
which every particle in the fluid follows the
same path past a particular point as that
followed by previous particles.


 Since 1989 there were at least 23 distinct type of technologies
available for the measurement of flow in closed conduit.
 The performance of flowmeters is also influenced by a
dimensionless unit called the Reynolds Number.
 The Reynolds number is used for determined whether a flow is
laminar or turbulent. Laminar flow within pipes will occur
when the Reynolds number is below the critical Reynolds
number of 2300 and turbulent flow when it is above 4000.
TYPES OF FLOW


Types of Flow
𝑅𝑒 =
𝜌.𝑑.𝑣
𝜇
𝜌 is the density in kg/m3
d is the diameter of the
pipe in m
V is the velocity of fluid
in m/s
𝜇 is the dynamic
viscosity in Pa.s


 1) The velocity of water in a pipe is 1.5 m/s. Calculate the
Reynolds number if the diameter is 0.1 m and the density and
viscosity are respectively 1000 kg/m3 and 0.001 Pa.s
 2) What will be the velocity for a Reynolds number of 2000.
Class activity


Quantity of a gas or liquid
moving through a pipe or
channel within a given or
standard period (usually a
minute or hour)
What is a Flow Rate ?


What is mass flow rate
Mass flow rate is the
mass of a substance
which passes per
unit of time.
Its unit is kg/s
(kilogram per
second) in SI units,


 1) What is the mass flow rate of 5 kg of water passing through
a tube during 1 min ?
 2) In 20 seconds, water passes a tube with a mass flow rate of
2kg/s. What is the mass of water?
Class work


Volume flow rate
Volume flow rate,
rate of fluid flow or
volume velocity) is
the volume of fluid
which passes per unit
time.
The SI unit is m3/s
(cubic meters per
second.
𝑄 =
𝑉𝑜𝑙𝑢𝑚𝑒
𝑡𝑖𝑚𝑒


Volume flow rate and
velocity
Volume flow rate
= Area x velocity
Q= A.v
 A = Cross-sectional Area of Pipe
(SI: m2)
 v = Velocity of the fluid in the
pipe (SI: m/s)


 1) In how many seconds, 3 m3 of water having flows with a
rate of 10 m3/s
 2) Water flowing in a tube having a area of 10 cm2. If the flow
rate is 1 m3/s, what will be the velocity in m/s?
Class work


Volume and mass flow
rates
 Mass flow rate is equal
to the volumetric flow
rate times the density.
 ṁ= ρ.Q
 Since Q = A. v
ṁ=ρ.A . v


 A liquid having a density of 800 kg/m3 has a volumetric flow
rate of 50 m3/s. What is its mass flow rate is kg/s?
 A fluid has a density of 1000 kg/m3 flows in a pipe of surface
are equals to 10 cm2. If the velocity is 1 m/s, what are the
volumetric and mass flow rates
Class activity


 Molecular flow rate is defined as mass flowrate divided by the
molecular weight.
 N =
𝑀𝑎𝑠𝑠 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒
𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑤𝑒𝑖𝑔ℎ𝑡
Molecular flow rate


1) What is the molecular flow rate of water if the mass
flow rate is 100 kg/s and the molecular weight is 18
2) What is the mass flow rate of gasoline if the
molecular flow rate is 50 moles/s and the molecular
weight is 80.
Class activity

September 23, 2004 115
Basic Flow Measurement

September 23, 2004 116
Type of Flowmeters
Industrial Flowmeter Usage


Orifice plate
An orifice plate is a thin
plate with a hole in it,
which is usually placed
in a pipe. When a fluid
passes through the
orifice, it is forced to
converge to pass through
the hole, the velocity
increases and the fluid
pressure decreases


Positive displacement
 A positive displacement
meter is a type of flow
meter that requires fluid to
mechanically displace
components in the meter in
order for flow measurement
 These devices consist of a
chamber(s) that obstructs
the media flow and a
rotating or reciprocating
mechanism that allows the
passage of fixed-volume
amounts.


INTRODUCTION
The pump is mechanical device which conveys liquid
from one place to another place.
It can be defined as a hydraulic machines which
converts the mechanical energy into hydraulic energy
( Pressure) .
The pump is power absorbing machine.
The power can be supplied to the pump by a prime
mover like an electric motor, an internal combustion
engine or turbine..


Pressure definition
Pressure is the action of one force
against another over, a surface. The
pressure P of a force F distributed
over an area A is defined as:
P = F/A


Pressure References
Absolute pressure
The pressure is referenced to zero absolute. Absolute
pressure can only have a positive value.
Gauge pressure
The pressure is referenced to atmospheric pressure:
P ( gauge ) = P ( absolute) – Atmospheric pressure
Vacuum pressure
Any pressure lower than atmospheric pressure is called
vacuum pressure.


UNITS OF PRESSURE
 SI UNITS:
1Pa = 1N/M2=1KG/S2.M
1ATM (ATMOSPHERIC PRESSURE)= 100 kPa
1 ATM= 101 kN/M2
1ATM= 760 MM. HG
 US UNITS:
1PSIA = 1LBF/IN2
1PSIA = 6894.7 Pa
1ATM= 14.696 PSIA
LISTEN..LEARN..THINK..ENJOY
YOURSELF
124


 1) A liquid in a pipe has an absolute pressure of 50 kPa. What
is the reading in the gauge if the atmospheric pressure is 101
kPa?
 2) You read in a manometer a pressure of -10 kPa. What is the
absolute pressure ?
 Convert 50 kPa into atm.
 Convert 2 atm into Psi.
Class activity


Head
 Connect a tube to the
discharge of a pump and
measure the water height, that
the head of the pump.
 Head is the height at which a
pump can raise water up.
 More pressure the pump
delivers, the higher the head
will be in the figure.


Pressure and Head
 Head and pressure are interchangeable terms provided that
they are expressed in their correct units.
 The conversion of all pressure terms into units of equivalent
head simplifies most pump calculations.
 ℎ =
𝑃.𝑔 𝑐
𝜌.𝑔


1) What is the head in m when the pressure is 98100 Pa and the
density of the liquid is 1000 kg/m3.
 g = 9.81 m/s and gc= 1kg.m/s2
 h = (98100 x 1)/ ( 1000x 9.81)= 10 m
 2) what is now the pressure if the head is 5 m?
Example + activity


Pump Performance
Curve
 A mapping or graphing of the pump's ability to produce head and flow


Pump Performance Curve
Step #1, Horizontal Axis
 The pump's flow rate is plotted on the horizontal
axis ( X axis)
 Usually expressed in Gallons per Minute
Pump Flow Rate


Step #2, Vertical Axis
Pump Flow Rate
The head the pump produces is
plotted on the vertical axis (Y axis)
Usually express in Feet of Water
Head


Mapping the Flow and the Head
Pump Flow Rate
Most pump
performance curves
slope from left to
right
Performance Curve
Head


Important Points
 Shut-off Head is the maximum pressure
or head the pump can produce
 No flow is produced
Pump Flow Rate
Head
Shut-off Head


Pump Performance
Curve
Important Points
Pump Flow Rate
Head
Maximum Flow
 Maximum Flow is the
largest flow the pump can
produce
 No Head is produced


System Performance Curves
System Performance Curve is a mapping of the
head required to produce flow in a given
system
A system includes all the pipe, fittings and
devices the fluid must flow through, and
represents the friction loss the fluid experiences


System Performance Curve
Step #1, Horizontal Axis
System Flow Rate
 The System's flow rate in plotted on the horizontal axis
( X axis)
 Usually expressed in Gallons per Minute


Step #2, Vertical Axis
Pump Flow Rate
 The head the system requires is plotted on the
vertical axis (Y axis)
 Usually express in Feet of Water
Head


Step #3, Curve Mapping
 The friction loss is mapped onto the graph
 The amount of friction loss varies with flow through
the system
Head
Pump Flow Rate
Friction Loss


Head
Pump Flow Rate
The point on the system curve that intersects the pump curve is
known as the operating point.


CLASSIFICATION OF
PUMPS
 Positive displacement pumps
1. Reciprocating pumps
2. Rotary pumps
 Roto -dynamic pump
1. Centrifugal pump
2. Propeller pump
3. Mixed flow pump


POSITIVE DISPLACEMENT
PUMPS:
RECIPROCATING PUMPS
 Reciprocating pump
classification
Reciprocating pumps can be
classified based on
 1. Sides in contact with water
a) Single acting Reciprocating
pump
b) Double acting reciprocating
pump
 2. Numbers of cylinder used
a) Single cylinder pump
b) Two cylinder pumps
c) Multi-cylinder pumps)


 This machine consists of an
IMPELLER rotating within a
case (diffuser)
 Liquid directed into the
center of the rotating
impeller is picked up by the
impeller’s vanes and
accelerated to a higher
velocity by the rotation of the
impeller and discharged by
centrifugal force into the case
(diffuser).
Centrifugal Pumps


Diameter of
the Impeller
Thickness
of the impeller
Centrifugal Impellers
Thicker the Impeller- More Water
Larger the DIAMETER - More Pressure
Increase the Speed - More Water and Pressure
Impeller
Vanes
“Eye of the
Impeller”
Water
Entrance


Two Impellers in Series
Direction of Flow
Twice the pressure
Same amount of water


Multiple Impellers in
Series
Placing impellers in series increases the amount of
head produced
The head produced = # of impellers x head of one
impeller
Direction of Flow Direction of Flow


Head
Pump Flow Rate
Circulator 1
Circulator 2
Circulator 3
PUMP SELECTION:3 pumps


Controlling Pump Performance
 Changing the amount for friction loss or "Throttling the
Pump" will change the pump's performance


Head
Pump Flow Rate
PUMP SELECTION
Valve Open
Valve Partially Open
Valve Barely Open


 What is a Compressor?
◦ A mechanical device that increases the pressure of a gas by
reducing its volume.
◦ Similar to a pump – Increases the pressure on a fluid and transport
it through a pipe.
 What is key difference between a Fluid and a Gas?
◦ Compressibility – a gas is compressible
 What happens to gas volume as it is compressed?
◦ Decreases
 What happens to the Temperature of the Gas as it is
compressed?
◦ Increases
Compressors

 Compressors are classified by how they work
 Two Categories of Compressors
◦ Positive Displacement
◦ Dynamic
 What is a Positive Displacement Compressor?
◦ A compressor that confines successive volumes of gas within a
closed space in which the pressure of the gas is increased as the
volume of the closed space is decreased.
 Intermittent Flow
 What is a Dynamic Compressor?
◦ A compressor using a rotating mechanism to add velocity and
pressure to gas.
 Continuous Flow
Compressors


Two types of Positive Displacement
Compressors:
Reciprocating
Rotary
Two Types of Dynamic Compressors
Centrifugal
Axial
Compressors


 Reciprocating Compressors
 How does it work?
 Piston movement in a cylinder connected to a rod and crankshaft
 Downward piston motion, low pressure gas enters the chamber
 Upward piston motion, gas is compressed and exits the chamber
 Video
Reciprocating Compressors

 Reciprocating Compressors
◦ High Horsepower Applications
 Common in natural gas transmission lines.
 Processes for high pressure delivery of gasses
◦ Air Conditioning Compressors
 Some manufactures (Frigidaire™) use rotary compressors
 AC Compressors (and other small appliance applications) are Hermetic
or Semi-Hermetic
Compressors


 Rotary Compressors
◦ How do they it work?
 When a rotating mechanism spins past the inlet valve, it creates a
vacuum.
 The fluid flows out of the valve behind it, filling the vacuum.
 As it approaches the outlet valve, the chamber shrinks, creating more
pressure on the fluid.
 The fluid has nowhere to go but out of the outlet valve, so it shoots out
of it.
 Then the rotating mechanism continues on to draw more fluid at the
inlet valve.
◦ How it works Video
Rotary Compressors

 Common Types of Rotary Compressors
◦ Screw
◦ Vane
◦ Scroll
 Screw
◦ Two meshing helix screws
 Rotors
◦ Compact and smooth running
◦ 2 types - Oil Free and Oil Flooded
 Oil Free – No assistance from oil to cool and assist in sealing .
 Oil Flooded – Oil injected to aid in sealing and provide cooling.
 Separator downstream to capture the oil
Rotary Compressors


 Vane Compressors
◦ Vane housing on a off centered shaft
◦ Vanes slide in an out always making
contact with the compressor walls
◦ Gas enters in the largest opening
◦ Exits the smallest
◦ Good for low pressure applications
◦ Efficient
◦ Heat controlled by
oil injection
Vane Compressors


 Scroll Compressor
◦ How it works
 2 Spirals
 1 stationary, 1 orbits without rotating
 1st orbit entraps inlet gas
 Subsequent orbits compresses gas and exited out the center
 Generally 2-3 orbits for a full cycle
 Video
◦ Advantages
 Compact
 Steady flow
 Low energy use
 Quiet
 Smooth operation
Scroll Compressors


 What is a Dynamic Compressor?
 A compressor using a rotating mechanism to add
velocity and pressure to gas.
 Continuous Flow
 What are the Two Types of Dynamic Compressors?
 Centrifugal
 Axial
Dynamic Compressors


 Centrifugal Compressors
 Rotating disk (impeller) forces gas to the rim of the
impeller, increasing velocity
 The diffuser converts the velocity energy to pressure
energy.
 Primarily used for continuous, stationary service in
industries such as refineries, chemical plants and snow
making operations
 Single Stage and Multi-Stage Compressors
 How a Centrifugal Compressor Works
Centrifugal Compressors


 Impeller
 Most critical part of a centrifugal compressor
 Compressor performance determined by impeller:
 Size
 Shape
 Speed
 3 types of Impellers
 Closed
 Most common
 Shroud covering both sides of the blade
 Center eye hole for gas to enter
 Used in Multi-stage compressors
 Semi –open
 Open
Compressors


 Multi-Stage Compressors
 Diaphragm
 Specially designed casing wall separating
the stages
 Gas passes through the difuser
 Passes through the return channel in the
diaphragm
 Controlling Axial Load on the Shaft
 Bearing Review
 Thrust Bearing
Multi Stage Compressors

 Axial Compressors
 Gas flows parallel to the axis of rotation
 Unlike centrifugal that has radial components
 Has rotating and stationary components
 Rotating airfoil – rotor
 Stationary airfoil – stator
 Similar number of these on
a shaft
Video
Axial Compressors


 Axial Compressors
 High Volume
 High Efficiency
 High Cost
 Common Uses
 Gas Turbines
 Jet engines
 Power stations
 Nickname – “Superchargers”
Axial Compressors


 1) How many moles of carbon have a mass of 36g
 2) What is the molecular weight of methane ( CH4) if 2 moles
contain 32 grams.
 3) What is the total mass of 1 mole of propane C3 H8
Class activity


 1) A solid has a density of 1600 kg/m3. What will be its mass
in a container of 5.5 m3 ?
 2) Water occupies a volume of 15 m3. What is the mass
 An unknown gas has a mass of 3.45 kg and occupies a volume
of 3 m3. What is the density?
Class activity


Find the mass composition of a mixture containing 20
grams of water , 35 grams of juice and 5 grams of
sugar.
Class activity


 1) The velocity of water in a pipe is 2 m/s. Calculate the
Reynolds number if the diameter is 0.15 m and the density and
viscosity are respectively 800 kg/m3 and 0.003 Pa.s
 2) What will be the velocity for a Reynolds number of 4000.
Class activity


 1) What is the mass flow rate of 6 kg of water passing through
a tube during 45 seconds ?
 2) In 10 seconds, water ( density = 1000 kg/m3) passes a tube
with a mass flow rate of 2m3 /s. What is the mass of water?
Class work


 1) In how many seconds, 5 m3 of water having flows with a
rate of 8 m3/s
 2) Water flowing in a tube having a area of 7 cm2. If the flow
rate is 1.5 m3/s, what will be the velocity in m/s?
Class work


 A liquid having a density of 1000 kg/m3 has a volumetric flow
rate of 60 m3/s. What is its mass flow rate is kg/s?
 A fluid has a density of 1000 kg/m3 flows in a pipe of surface
are equals to 2 m2. If the velocity is 1.5 m/s, what are the
volumetric and mass flow rates
Class activity


1) What is the molecular flow rate of a liquid if the
mass flow rate is 70 kg/s and the molecular weight is
38
2) What is the mass flow rate of gasoline if the
molecular flow rate is 50 moles/s and the molecular
weight is 80.
Class activity


 1) A liquid in a pipe has an absolute pressure of 150 kPa. What
is the reading in the gauge if the atmospheric pressure is 101
kPa?
 2) You read in a manometer a pressure of 40 kPa. What is the
absolute pressure ?
 Convert 0.5 atm into Pa.
 Convert 50 kPa into Psi.
Class activity


1) What is the head in m when the pressure is 100100 Pa and
the density of the liquid is 800 kg/m3.
 g = 9.81 m/s and gc= 1kg.m/s2
Example + activity

Welcome to Process Operations for Diploma students

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Welcome to Process Operations for Diploma students