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Lecture Notes of Industerial Equipments

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Fundamentals of Industrial Equipment provides students with a thorough introduction to the diagnosis, repair, and maintenance of industrial equipment. With comprehensive, up-to-date coverage of the latest technology in the field, it addresses the equipment used in construction, oil and gas industry, and mining industries. The primary purpose of mechanical fitting is to transmit forces across parts of a system with as little loss as possible and with minimum of wear. The better the fits the more efficient the system. The primary units required to be fitted are gears, clutches, couplings, belt and chain drives and bearings. To produce these forces there are four main units: pumps, compressors, engines and electrical motors. The major aspects of these devices will be discussed in relation to proper maintenance procedures, fault-finding methods and fitting techniques. The information given can be applied in almost every instance of maintenance fitting and will provide a springboard for acquiring more advanced techniques and knowledge in the areas outlined. Where specific areas have not been covered the methods and information given can be interpolated to fit the circumstances at the time.
Content may be subject to copyright.
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INDUSTRIAL EQUIPMENTS
Barhm Abdullah Mohamad
Erbil Polytechnic University
LinkedIn: https://www.linkedin.com/in/barhm-mohamad-900b1b138/
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YouTube channel: https://www.youtube.com/channel/UC16-u0i4mxe6TmAUQH0kmNw
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Contents
Overview
1.1 Pumps
1.2 Type of pumps
1.2.1 Positive displacement Pumps
1.2.2 The components of rotary pumps
1.2.3 Advantage of positive displacement pumps
1.2.4 Disadvantage of positive displacement pumps
1.3 Dynamic pumps
1.3.1 Centrifugal pump components
1.3.2 Types of casings
1.3.3 Advantage of centrifugal pumps
1.3.4 Disadvantage of centrifugal pumps
2.1 Compressors
2.1.1 Standard Units and Conditions
2.2 Positive displacement compressors
2.2.1 Advantage of positive displacement compressors
2.2.2 Disadvantage of positive displacement compressors
2.3 Dynamic compressor
2.3.1 Centrifugal compressors systems
2.3.2 Axial compressors
2.3.3 Advantage of dynamic compressors
2.3.4 Disadvantage of dynamic compressors
2.4 Stalling phenomenon
2.5 Compressors components
2.5.1 Receiver tanks or the air receivers
2.5.2 Air dryers
2.5.3 Filters
2.5.4 Piping distribution system
3.1 Engines
3.2 Electrical engines
3.2.1 The components of electrical motors
3.2.2 Uses of electrical motors
3.2.3 The advantage of electrical engine or motor
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3.2.4 The disadvantage of electrical engine or motors
3.3 Electrical generator
3.3.1 The difference between electrical motors and electrical generators
3.4 External combustion engine
3.4.1 Steam engines
3.5 Internal combustion engine
3.5.1 Type of engine according to design
3.5.2 Type of engine according to fuel combustion
3.5.3 Diesel engine
3.5.4 Engine parts
3.5.5 Engine parameters
3.5.6 The difference between SI engine and CI engine
4.1 Crude oil storages
4.2 Type of crude oil storages
4.3 Crude oil storage components
5.1 Reactors
5.2 Type of reactors according to phase
5.3 Type of reactor according to design
5.4 Catalyst
5.5 Reactor design
6.1 Heating, ventilation and air conditioning [HVAC]
6.2 Refrigeration cycle
6.2.1 Ideal vapor-compression refrigeration cycle process description
7.1 Upstream process sections in oil and gas location
7.1.1 Wellheads
7.1.2 Manifolds
7.1.3 Separation
7.1.4 Metering, storage and export
7.1.5 Utility systems
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Overview
Fundamentals of Industrial Equipment provides students with a thorough introduction
to the diagnosis, repair, and maintenance of industrial equipment. With
comprehensive, up-to-date coverage of the latest technology in the field, it addresses
the equipment used in construction, oil and gas industry, and mining industries.
The primary purpose of mechanical fitting is to transmit forces across parts of a
system with as little loss as possible and with minimum of wear. The better the fits the
more efficient the system. The primary units required to be fitted are gears, clutches,
couplings, belt and chain drives and bearings. To produce these forces there are four
main units: pumps, compressors, engines and electrical motors. The major aspects of
these devices will be discussed in relation to proper maintenance procedures,
fault-finding methods and fitting techniques. The information given can be applied in
almost every instance of maintenance fitting and will provide a springboard for
acquiring more advanced techniques and knowledge in the areas outlined. Where
specific areas have not been covered the methods and information given can be
interpolated to fit the circumstances at the time.
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Chapter 1
1.1 Pumps
A mechanical device using suction or pressure to raise or move liquids and compress
gases. Pumps operate by some mechanism (typically reciprocating or centrifugal) and
consume energy to perform mechanical work by moving the fluid. Pumps operate via
many energy sources, including manual operation, electricity, engines, or wind power,
come in many sizes, from microscopic for use in medical applications to large
industrial pumps.
Mechanical pumps serve in a wide range of applications such as pumping water from
wells, in the car industry for water-cooling and fuel injection, in the energy industry
for pumping oil and natural gas or for operating cooling towers. In the medical
industry, pumps are used for biochemical processes in developing and manufacturing
medicine.
1.2 Type of pumps
Mechanical pumps according to position may be submerged in the fluid they are
pumping or be placed external to the fluid.
Pumps can be classified according to the operating principle:
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1.2.1 Positive displacement pumps
Positive displacement pumps are distinguished by the way they operate when liquid is
taken from one end and positively discharged at the other end for every revolution.
In all positive displacement type pumps, a fixed quantity of liquid is pumped after
each revolution. So, if the delivery pipe is blocked, the pressure rises to a very high
value, which can damage the pump.
Positive displacement pumps are widely used for pumping fluids other than water,
mostly viscous fluids.
Positive displacement pumps are further classified based upon the mode of
displacement:
a) Reciprocating pumps if the displacement is by reciprocation of a piston
plunger. Those pumps are used only for pumping viscous liquids and oil
wells like chemical injection pump (see fig.1).
The components of reciprocating pumps are (rings, piston, rod piston,
piston cylinder, inlet and outlet valves and the camshaft.
b) Rotary pumps if the displacement is by rotary action of a gear, cam or
vanes in a chamber of diaphragm in a fixed casing. Rotary pumps are
further classified such as internal gear, external gear, lobe and slide vane.
More than 10% of the pumps installed in an industry are rotary pumps.
These pumps are used for special services with particular conditions
existing in industrial sites like highly viscous petroleum production in
vacuum distillation refinery.
Fig.1 Reciprocating pumps
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1.2.2 The components of rotary pumps
a) Housing: to cover and keep the impeller, gears or reciprocating piston with the
fluid under high pressure.
b) Rotor: to convert kinetic energy to pressure and velocity by rotation.
c) Vane: to apply force on the viscous fluid and produce pressure.
d) Inlet/outlet valves: to allow the fluid to in or out from the housing.
e) Mechanical seals: is a device consist of two-part stator and rotor separated by
lubricant gasket, this mechanical seal used to prevent leakage from bearings
and casing of most type of pumps.
Fig.2 Components of centrifugal pump
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Fig.3 External gear rotary pump
1.2.3 Advantage of positive displacement pumps
a) Higher pressure produces using regular motor.
b) Flow doesn’t change when pressure changes.
c) Easy to maintenance.
d) Low in cost according to others.
e) Easy to operate and fitting.
f) Small areas require.
1.2.4 Disadvantage of positive displacement pumps
a) Low flow serves.
b) Low efficiency due to losses.
c) Higher level of safety requires to operating the pump.
d) Operate the pump with discharge valve closed may cause damage to the pump
casing.
e) Used for chemical injection and light duties only.
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Fig.4 Internal gear rotary pump
1.3 Dynamic pumps
Dynamic pumps are also characterized by their mode of operation: a rotating impeller
converts kinetic energy into pressure or velocity that is needed to pump the fluid.
Centrifugal pumps are pure example of dynamic pumps in industry, typically, more
than 75% of the pumps installed in an industry are centrifugal pumps.
The fig. 5 shows how this type of pump operates; the liquid is forced into an impeller
either by atmospheric pressure or in case of a jet pumps by artificial pressure.
The vanes of impeller pass kinetic energy to the liquid, thereby causing the liquid to
rotate. The liquid leaves the impeller at high velocity.
The impeller is surrounded by a volute casing or in case of a turbine pumps a
stationary diffuser ring. The volute or stationary diffuser ring converts the kinetic
energy into pressure energy.
A centrifugal pump has two main components; First, a rotating component
comprised of an impeller and a shaft. And secondly, a stationary component
comprised of a casing, casing cover, and bearings.
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Fig.5 Centrifugal pump components (Static and Rotor)
1.3.1 Centrifugal pump components
a) Impeller
An impeller is a circular metallic disc with a built-in passage for the flow of fluid.
Impellers are generally made of bronze, polycarbonate, cast iron or stainless steel, but
other materials are also used.
The number of impellers determines the number of stages of the pump. A single stage
pump has one impeller and is best suited for low head (1bar unit pressure = 10-meter
head).
Impellers can be classified on the basis of which will determine their use major
direction of flow from the rotation axis Suction type: single suction and double
suction.
b) Shaft
The main uses of shaft to transfers the torque from the motor to the impeller during
the startup and operation of the pump.
c) Casing
Casings have two functions:
I. The main function of casing is to enclose the impeller at suction and delivery
ends and thereby form a pressure vessel.
II. A second function of casing is to provide a supporting and bearing medium for
the shaft and impeller sometimes called (bearing house) or (housing).
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1.3.2 Types of casings
a) Volute casing (see fig.6) has impellers that are fitted inside the casings. One of
the main purposes is to help balance the hydraulic pressure on the shaft of the
pump.
b) Circular casing (see fig.7) has stationary diffusion vanes surrounding the
impeller periphery that convert speed into pressure energy. These casings are
mostly used for multi-stage pumps [1]. The casings can be designed as solid
casing (one fabricated piece) or split casing (two or more parts together).
Fig.6 Volute casing of centrifugal pump
Fig.7 Circular casing of centrifugal pump
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1.3.3 Advantage of centrifugal pumps
a) Larger flow serves.
b) Higher efficiency.
c) Friction losses are less.
d) Less power consumption.
e) Easy to maintenance due to multipart.
f) More safety and less damage than others.
g) Heavy duties, malty purpose pump and widely use.
1.3.4 Disadvantage of centrifugal pumps
a) Consider as low-pressure pump.
b) Flow changes when pressure changes.
c) Higher in cost.
d) Big and flat area requires to preventing losses.
e) Slip losses due to the speed of impeller (2000-3000) rpm.
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Chapter 2
2.1 Compressors
Air Compressors is used for machine and tool operation, drilling, painting, soot
blowing, instrument operations, and in situ operations (e.g., underground combustion).
Pressures range from 5 bar = 500 kpa to the largest usage is at 25 bar = 2500 kpa
which is normal plant air pressure range and can appear on the compressor pressure
gages by law.
Gas compressors are used for refrigeration, air conditioning, heating, pipeline
conveying, natural gas gathering, catalytic cracking, polymerization, and in other
chemical processes.
2.1.1 Standard Units and Conditions
In the ISO system, the standard unit of pressure for compressors is the kilopascal
(kPa). In some countries this is the only unit which can appear on the compressor
pressure gages by law. In Europe, the European Committee of Manufacturers of
Compressors, Vacuum Pumps and Pneumatic Tools (PNEUROP) and, in the United
States, the Compressed Air and Gas Institute (CAGI) prefer the bar as the standard
unit of pressure. PNEUROP and CAGI have selected as standard conditions 1 bar
(14.5 lb/in²) (100 kPa), 20°C (68°F), and 0 percent relative humidity. The unit of flow
in the ISO system is m3/s. Other units still in common usage are m3/h, m3/min, and
L/s. In the United States the most commonly used units are ft3/min (cfm) and ft3/h
(cfh). Power is normally expressed in kilowatts (PNEUROP) and horsepower (CAGI).
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2.2 Positive displacement compressors
There are two types of positive displacement compressors according to flow and
design:
a) Reciprocating compressors: consider as positive displacement compressors.
This means they are taking in successive volumes of air which is confined within
a closed space and elevating this air to a higher pressure. The reciprocating
compressor accomplishes this by using a piston within a cylinder as the
compressing and displacing element.
The reciprocating compressor is considered single acting when the compressing is
accomplished using only one side of the piston. A compressor using both sides of the
piston is considered double acting. The reciprocating compressor uses a number of
automatic spring-loaded valves in each cylinder that open only when the proper
differential pressure exists across the valve.
Inlet valves open when the pressure in the cylinder is slightly below the intake
pressure. Discharge valves open when the pressure in the cylinder is slightly above
the discharge pressure.
A compressor is considered to be single stage when the entire compression is
accomplished with a single cylinder or a group of cylinders in parallel. Many
applications involve conditions beyond the practical capability of a single
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compression stage. Too great a compression ratio (absolute discharge
pressure/absolute intake pressure) may cause excessive discharge temperature or other
design problems.
For practical purposes most plant air reciprocating compressors over 100 horsepower
are built as multi-stage units in which two or more steps of compression are grouped
in series. The air is normally cooled between the stages to reduce the temperature and
volume entering the following stage.
Reciprocating air compressors are available either as air-cooled or water-cooled in
lubricated and non-lubricated configurations, may be packaged, and provide a wide
range of pressure and capacity selections.
Fig.8 Single stage reciprocating compressor
b) Rotary screw compressors: Rotary screw compressors are positive
displacement compressors.
The most common rotary compressor is the single stage helical or spiral lobe oil
flooded screw air compressor. These compressors consist of two rotors within a
casing where the rotors compress the air internally. There are no valves. These units
are basically oil cooled (with air cooled or water-cooled oil coolers) where the oil
seals the internal clearances.
Since the cooling takes place right inside the compressor, the working parts never
experience extreme operating temperatures. The rotary compressor, therefore, is a
continuous duty, air cooled or water-cooled compressor package.
Because of the simple design and few wearing parts, rotary screw air compressors are
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easy to maintain, operate and provide great installation flexibility. Rotary air
compressors can be installed on any surface that will support the static weight.
The two-stage oil flooded rotary screw air compressor uses pairs of rotors in a
combined air end assembly. Compression is shared between the first and second
stages flowing in series. This increases the overall compression efficiency up to
fifteen percent of the total full load kilowatt consumption. The two-stage rotary air
compressor combines the simplicity and flexibility of a rotary screw compressor with
the energy efficiency of a two-stage double acting reciprocating air compressor. Two
stage rotary screw air compressors are available air cooled, and water cooled and fully
packages.
The oil free rotary screw air compressor utilizes specially designed air ends to
compress air without oil in the compression chamber yielding true oil free air. Oil free
rotary screw air compressors are available air cooled, and water cooled and provides
the same flexibility as oil flooded rotaries when oil free air is required.
Rotary screw air compressors are available air cooled, and water cooled, oil flooded
and oil free, single stage and two stages. There is a wide range of availability in
configuration and in pressure and capacity.
2.2.1 Advantage of positive displacement compressors
a) Higher pressure produces using regular motor.
b) Flow depends on pressure ratio of compressor stage.
c) Easy to maintenance.
d) Low in cost according to others.
e) Safety and easy to operate and fitting.
f) Small areas require.
g) Safety valve release valves are fitted to reduce hazard and damages to
compressors.
2.2.2 Disadvantage of positive displacement compressors
a) Low flow serves.
b) Low efficiency due to losses.
c) Air filter and dryers requires to producing wet and dry air that suitable for
electrical instruments.
d) Higher level of safety requires to operating the compressors.
e) Used for light duties, refrigeration and air conditioning only.
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Fig.9 Single stage rotary screw air compressor
2.3 Dynamic compressor
Dynamic compressors are capable of delivering large volumes of air but little pressure
(0.5-3bar). These compressors are usually known as blowers and work by drawing air
in and throwing it out with the use of rotary fins, these fins rotate at very high speed.
There are two main types of dynamic compressor, they are centrifugal and axial.
2.3.1 Centrifugal compressors
Use centrifugal force to hurl air out from the fins, centrifugal systems can generally
obtain greater pressures than the axial type of compressor. Centrifugal Compressors
The centrifugal compressor considered as dynamic compressor which depends on
transfer of energy from a rotating impeller to the air. The rotor accomplishes this by
changing the momentum and pressure of the air. This momentum is converted to
useful pressure by slowing the air down in a stationary diffuser. The centrifugal air
compressor is an oil free compressor by design. The oil lubricated running gear is
separated from the air by shaft seals and atmospheric vents. The centrifugal is a
continuous duty compressor, with few moving parts, that is particularly suited to high
volume applications, especially where oil free air is required. Centrifugal air
compressors are water cooled and may be packaged; typically, the package includes
the after-cooler and all controls.
2.3.2 Axial compressors
Type compressor uses a set of fan blades in line to generate large air flow, pressures
from this method aren’t expected to reach much over 0.5 bar. The axial compressors
are largely used for ventilation and as part of air processing.
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Fig.10 Single stage centrifugal compressor
2.3.3 Advantage of dynamic compressors
a) Larger flow serve produces using regular motor.
b) Flow depends on pressure ratio of compressor stage.
c) Easy to maintenance.
d) Higher efficiency.
e) Less damage due to centrifugal system.
f) Safety and easy to operate.
g) Safety valve release valves are fitted to reduce hazard and damages to
compressors.
h) Dynamic compressors used for heavy duties in industrials.
2.3.4 Disadvantage of dynamic compressors
a) Lower pressure produces.
b) Higher in cost.
c) Big area requires and difficult to install and fitting.
d) Air filter and dryers requires to producing wet and dry air that suitable for
electrical instruments.
e) High electric power requires to operating the compressor.
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Fig.11 Axial compressor
2.4 Stalling phenomenon
Stalling is an important phenomenon that affects the performance of the compressor.
An analysis is made of rotating stall in compressors of many stages, finding
conditions under which a flow distortion can occur which is steady in a traveling
reference frame, even though upstream total and downstream static pressure are
constant. In the compressor, a pressure rise hysteresis is assumed. It is a situation of
separation of air flow at the aero-foil blades of the compressor. This phenomenon
depending upon the blade profile leads to reduced compression and drop in engine
power. Positive Stalling flow separation occurs on the suction side of the blade.
Negative Stalling flow separation occurs on the pressure side of the blade. Negative
stall is negligible compared to the positive stall because flow separation is least likely
to occur on the pressure side of the blade.
In a multi-stage compressor, at the high-pressure stages, axial velocity is very small.
Stalling value decreases with a small deviation from the design point causing stall
near the hub and tip regions whose size increases with decreasing flow rates. They
grow larger at very low flow rate and affect the entire blade height. Delivery pressure
significantly drops with large stalling which can lead to flow reversal. The stage
efficiency drops with higher losses [2].
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Fig.12 Multistage axial compressor
2.5 Compressor components
2.5.1 Receiver tanks or the air receivers
a) Provide storage capacity to prevent rapid compressor cycling.
b) Reduce wear and tear on compression module, inlet control system, and
motor.
c) Eliminate pulsing air flow.
d) Avoid overloading purification system with surges in air demand.
e) Damp out the dew point and temperature spikes that follow regeneration.
Fig.13 Multi-stage centrifugal compressor
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2.5.2 Air dryers
a) Refrigerated air dryers: Refrigerated air dryers remove moisture from the
compressed air through a mechanical refrigeration system to cool the
compressed air and condense water and lubricant vapor. Most refrigerated
dryers cool the compressed air to a temperature of approximately 35°F,
resulting in a pressure dew point range of 33°F - 39°F. Keep in mind that this
range is also the lowest achievable with a refrigerated design since the
condensate begins to freeze at 32°F.
b) Desiccant dryers: Desiccant dryers utilize chemicals beads, called desiccant,
to adsorb water vapor from compressed air. Silica gel activated alumina and
molecular sieve are the most common desiccants used. (Silica gel or activated
alumina is the preferred desiccants for compressed air dryers). The desiccant
provides an average -40°F pressure dew point performance. Molecular sieve is
usually only used in combination with silica gel or activated alumina on
-100°F pressure dew point applications.
c) Deliquescent air dryers: Deliquescent air dryers utilize an absorptive type
chemical, called a desiccant, to provide a 20°F to 25°F dew point suppression
below the temperature of the compressed air entering the dryer. The moisture
in the compressed air reacts with the absorptive material to produce a liquid
effluent which is then drained from the dryer. Keep in mind that this effluent is
typically corrosive and must be disposed of in accordance with local
regulations.
2.5.3 Filters
Coalescing filters are the most common form of compressed air purification. These
filters remove liquid water and lubricants from compressed air and are installed
downstream in a refrigerated air dryer system or upstream in a desiccant dryer system.
Filters are rated according to liquid particle retention size (micron) and efficiency,
such as 0.50 micron and 99.99% D.O.P. efficient, or 0.01 micron and 99.9999%
D.O.P efficient.
Coalescing filters can only remove previously condensed liquids; they do not remove
water or lubricant vapors from the compressed air. Any condensation produced from
subsequent compressed air cooling will have to be eliminated. When seeking to
remove water and lubricant vapors from compressed air, specify an air dryer.
2.5.4 Piping distribution system
The piping distribution system not only controls how the air gets from the compressor
room to the tools, but it is also a major factor in the energy consumed by the
compressor.
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Fig.14 Air compressor system and components
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Chapter 3
3.1 Engines
An engine or motor is a machine designed to convert energy into useful mechanical
motion. Heat engines, including internal combustion engines and external combustion
engines (such as steam engines) burn a fuel to create heat, which then creates motion.
Electric motors convert electrical energy into mechanical motion, pneumatic motors
use compressed air and others, such as clockwork motors in wind-up toys, use elastic
energy. In biological systems, molecular motors, like myosin in muscles, use chemical
energy to create motion.
In modern usage, the term engines typically describe devices, like steam engines and
internal combustion engines, that burn or otherwise consume fuel to perform
mechanical work by exerting a torque or linear force to drive machinery that
generates electricity, pumps water, or compresses gas. In the context of propulsion
systems, an air-breathing engine is one that uses atmospheric air to oxidize the fuel
rather than supplying an independent oxidizer, as in a rocket [3].
When the internal combustion engine was invented, the term "motor" was initially
used to distinguish it from the steam engine which was in wide use at the time,
powering locomotives and other vehicles such as steam rollers. "Motor" and "engine"
later came to be used interchangeably in casual discourse. However, technically, the
two words have different meanings. An engine is a device that burns or otherwise
consumes fuel, changing its chemical composition, whereas a motor is a device driven
by electricity, which does not change the chemical composition of its energy source.
A heat engine may also serve as a prime mover a component that transforms the flow
or changes in pressure of a fluid into mechanical energy. An automobile powered by
an internal combustion engine may make use of various motors and pumps, but
ultimately all such devices derive their power from the engine. Another way of
looking at it is that a motor receives power from an external source, and then converts
it into mechanical energy, while an engine creates power from pressure (derived
directly from the explosive force of combustion or other chemical reaction, or
secondarily from the action of some such force on other substances such as air, water,
or steam).
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Devices converting heat energy into motion are commonly referred to simply as
engines.
3.2 Electrical engines
An electric motor is an electric machine that converts electrical energy into
mechanical energy.
In normal motoring mode, most electric motors operate through the interaction
between an electric motor's magnetic field and winding currents to generate force
within the motor. In certain applications, such as in the transportation industry with
traction motors, electric motors can operate in both motoring and generating or
braking modes to also produce electrical energy from mechanical energy.
Found in applications as diverse as industrial fans, blowers and pumps, machine tools,
household appliances, power tools, and disk drives, electric motors can be powered by
direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or by
alternating current (AC) sources, such as from the power grid, inverters or generators.
Small motors may be found in electric watches. General purpose motors with highly
standardized dimensions and characteristics provide convenient mechanical power for
industrial use. The largest of electric motors are used for ship propulsion, pipeline
compression and pumped storage applications with ratings reaching 100 megawatts.
Electric motors may be classified by electric power source type, internal construction,
application, type of motion output, and so on.
Devices such as magnetic solenoids and loudspeakers that convert electricity into
motion but do not generate usable mechanical power are respectively referred to as
actuators and transducers [4]. Electric motors are used to produce linear force or torque
(rotary).
Fig.15 Electrical engines (Electrical motors).
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3.2.1 The components of electrical motors
a) Rotor
In an electric motor the moving part is the rotor which turns the shaft to deliver
the mechanical power. The rotor usually has conductors laid into it which carry
currents that interact with the magnetic field of the stator to generate the forces
that turn the shaft. However, some rotors carry permanent magnets, and the stator
holds the conductors.
b) Stator
The stationary part is the stator, usually has either windings or permanent magnets.
The stator is the stationary part of the motor’s electromagnetic circuit. The stator
core is made up of many thin metal sheets, called laminations. Laminations are
used to reduce energy losses that would result if a solid core were used.
c) Air gap
In between the rotor and stator is the air gap. The air gap has important effects,
and is generally as small as possible, as a large gap has a strong negative effect on
the performance of an electric motor.
d) Windings
Windings are wires that are laid in coils, usually wrapped around a laminated soft
iron magnetic core so as to form magnetic poles when energized with current.
Electric machines come in two basic magnet field pole configurations: salient-pole
machine and non-salient-pole machine. In the salient pole machine, the pole's
magnetic field is produced by a winding wound around the pole below the pole
face. In the non-salient pole, or distributed field, or round-rotor, machine, the
winding is distributed in pole face slots. A shaded-pole motor has a winding
around part of the pole that delays the phase of the magnetic field for that pole.
Some motors have conductors which consist of thicker metal, such as bars or
sheets of metal, usually copper, although sometimes aluminum is used. These are
usually powered by electromagnetic induction.
e) Commutator
A commutator is a mechanism used to switch the input of certain AC and DC
machines consisting of slip ring segments insulated from each other and from the
electric motor's shaft. The motor's armature current is supplied through the
stationary brushes in contact with the revolving commutator, which causes
required current reversal and applies power to the machine in an optimal manner
26
as the rotor rotates from pole to pole. In absence of such current reversal, the
motor would brake to a stop. In light of significant advances in the past few
decades due to improved technologies in electronic controller, sensor less control,
induction motor, and permanent magnet motor fields, electromechanically
commutated motors are increasingly being displaced by externally commutated
induction and permanent magnet motors [5].
Fig.16 The structure of electrical motors
Fig.17 The electrical motors
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3.2.2 Uses of electrical motors
a) To convert electrical power to mechanical work.
b) To drive rotary machine in industrial like, pumps, fans and lifting system.
3.2.3 The advantage of electrical engine or motor
a) Easy operation and maintenance.
b) No environment pollution and noise less.
c) Not require cooling system.
d) Safety and easy control.
e) Variable speed.
3.2.4 The disadvantage of electrical engine or motors
a) Used in light duties in industrials.
3.3 Electrical generator
In electricity generation, an electric generator is a device that converts mechanical
energy to electrical energy. A generator forces electric current to flow through an
external circuit. The source of mechanical energy may be a reciprocating or turbine
steam engine, water falling through a turbine or waterwheel, an internal combustion
engine, a wind turbine, a hand crank, compressed air, or any other source of
mechanical energy. Generators provide nearly all of the power for electric power
grids.
The reverse conversion of electrical energy into mechanical energy is done by an
electric motor, and motors and generators have many similarities. Many motors can
be mechanically driven to generate electricity and frequently make acceptable
generators as you see in fig.18 below:
(a) (b)
Fig. 18 Electrical generator
(a) Electrical generator drive by turbine engine.
(b) Electrical generator drive by internal combustion engine.
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3.3.1 The difference between electrical motors and electrical generators
a) A generator converts electrical energy to mechanical energy, while a motor
converts mechanical energy to electrical energy.
b) In a generator, a shaft attached to the rotor is driven by a mechanical force and
electric current is produced in the armature windings, while the shaft of a motor is
driven by the magnetic forces developed between the armature and field; current
has to be supplied to the armature winding.
c) Motors (generally a moving charge in a magnetic field) obey the Fleming`s Left
Hand Rule, while the generator obeys Fleming’s Right Hand Rule.
3.4 External combustion engine
The difference between internal and external combustion engines, as their names
Suggest, is that the former burn their fuel within the power cylinder, but the latter use
their fuel to heat a gas or a vapor through the walls of an external chamber, and the
heated gas or vapors is then transferred to the power cylinder. External combustion
engines therefore require a heat exchanger, or boiler to take in heat, and as their fuels
are burnt externally under steady conditions, they can in principle use any fuel that
can burn, including agricultural residues or waste materials.
There are two main families of external combustion engines; steam engines which
rely on expanding steam (or occasionally some other vapors) to drive a mechanism; or
Stirling engines which use hot air (or some other hot gas). The use of both
technologies reached their zeniths around 1900 and has declined almost to extinction
since [6].
However, a brief description is worthwhile, since:
I. They were successfully and widely used in the past for pumping water.
II. They both have the merit of being well suited to the use of low-cost fuels such
as coal, peat and biomass.
III. Attempts to update and revive them are taking place.
The primary disadvantage of e.c. engines is that a large area of heat exchanger is
necessary to transmit heat into the working cylinder(s) and also to reject heat at the
end of the cycle. As a result, e.c. engines are generally bulky and expensive to
construct compared with i.c. engines. Also, since they are no longer generally
manufactured, they do not enjoy the economies of mass-production available to i.e.
engines. They also will not start so quickly or conveniently as an i.c. engine; because
it takes time to light the fire and heat the machine to its working temperature.
29
Due to their relatively poor power/weight ratio and also the worse energy/weight ratio
of solid fuels, the kinds of applications where steam or Stirling engines are most
likely to be acceptable are for static applications such as as irrigation water pumping
in areas where petroleum fuels are not readily available but low-cost solid fuels are.
On the positive side, e.c. engines have the advantage of having the potential to be
much longer lasting than i.c. engines (100-year-old steam railway locomotives are
relatively easy to keep in working order, but it is rare for i.c. engines to be used more
than 20 years or so engines are also significantly quieter and free of vibrations than i.c.
engines. The level of skill needed for maintenance may also be lower, although the
amount of time spent will be higher, particularly due to the need for cleaning out the
furnace.
Modern engineering techniques promise that any future steam or Stirling engines
could benefit from features not available over 60 years ago when they were last in
general use.
is in hand in various countries on a limited, however it will probably be some years
before a new generation of multi-fuel Stirling or steam powered pumps become
generally available.
Fig.19 External combustion engine
3.4.1 Steam engines
Only a limited number of small steam engines are available commercially at present
most are for general use or for powering small pleasure boats. A serious attempt to
develop a 2kW steam engine for use in remote areas was made by the engine
designers, Ricardos, in the UK during the 1950s. That development was possibly
30
premature and failed, but there is currently a revival of interest in developing power
sources that can run on biomass-based fuels. However, small steam engines have
always suffered from their need to meet quite stringent safety requirements to avoid
accidents due to boiler explosions, and most countries have regulations requiring the
certification of steam engine boilers, which is a serious, but necessary, inhibiting
factor.
The principle of the steam engine is illustrated in Fig. 19. Fuel is burnt in a furnace
and the hot gases usually pass-through tubes surrounded by water (fire tube boilers).
Steam is generated under pressure typically 5 to 10 atmospheres (or 5-10bar). A safety
valve is provided to release steam when the pressure becomes too high so as to avoid
the risk of an explosion. High pressure steam is admitted to a power cylinder through
a valve, where it expands against a moving piston to do work while its pressure drops.
The inlet valve closes at a certain point, but the steam usually continues expanding
until it is close to atmospheric pressure, when the exhaust valve opens to allow the
piston to push the cooled and expanded steam out to make way for a new intake of
high-pressure steam.
The valves are linked to the drive mechanism so as to open or close automatically at
the correct moment. The period of opening of the inlet valve can be adjusted by the
operator to vary the speed and power of the engine.
3.5 Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel
(normally a fossil fuel) occurs with an oxidizer (usually air) in a combustion chamber.
In an internal combustion engine, the expansion of the high-temperature and pressure
gases produced by combustion applies direct force to some component of the engine,
such as pistons, turbine blades, or a nozzle. This force moves the component over a
distance, generating useful mechanical energy.
The term internal combustion engine usually refers to an engine in which combustion
is intermittent, such as the more familiar four-stroke and two-stroke piston engines,
along with variants, such as the Wankel rotary engine. A second class of internal
combustion engines use continuous combustion: gas turbines, jet engines and most
rocket engines, each of which are internal combustion engines on the same principle
as previously described.
31
Fig.20 Internal combustion engine
3.5.1 Type of engine according to design
a) Two stroke engines
The two-stroke type of internal combustion engine is typically used in utility or
recreational applications which require relatively small, inexpensive, and
mechanically simple motors (chainsaws, jet skis, small motorcycles, etc).
The two-stroke engine is simple in construction, but complex dynamics are employed
in its operation. There are several features unique to a two-stroke engine. First, there
is a reed valve between the air-fuel intake and the crankcase. Air-fuel mixture enters
the crankcase and is trapped there by the one-way reed valve. Next, the cylinder has
no valves as in a conventional four stroke engine. Intake and exhaust are
accomplished by means of ports special holes cut into the cylinder wall which allows
fuel-air mixture to enter from the crankcase, and exhaust to exit the engine. These
ports are uncovered when the piston is in the down position.
Air-fuel mixture is drawn into the crankcase from the carburetor or fuel injection
system through the reed valve. When the piston is forced down, the exhaust port is
uncovered first, and hot exhaust gases begin to leave the cylinder. As the piston is
now in the down position, the crankcase becomes pressurized, and when the intake
port into the cylinder is uncovered, pressurized air-fuel mixture enters the chamber.
Both the intake and exhaust ports are open at the same time, which means the timing
and air flow dynamics are critical to proper operation. As the piston begins to move
up, the ports are closed off, and the air-fuel mixture compresses and is ignited; the hot
gases increase in pressure, pushing the piston down with great force and creating
work for the engine [7].
32
The major components of two-stroke engines are tuned so that optimum airflow
results. Intake and exhaust tubes are tuned so that resonances in airflow give better
flow than a straight tube. The cylinder ports and piston top are shaped so that the
intake and exhaust flows do not mix.
b) Four strokes
The four-stroke internal combustion engine is the type most commonly used for
automotive and industrial purposes today (cars and trucks, generators, etc). On the
first (downward) stroke of the piston, fuel/air is drawn into the cylinder. The
following (upward) stroke compresses the fuel-air mixture, which is then ignited
expanding exhaust gases then force the piston downward for the third stroke, and the
fourth and final (upward) stroke evacuates the spent exhaust gasses from the cylinder.
The four-stroke cycle is more efficient than the two-stroke cycle but requires
considerably more moving parts and manufacturing expertise.
Fig.21 Two stroke engine cycles
3.5.2 Type of engine according to fuel combustion
a) Spark ignition engine (gasoline engine):
The term spark-ignition engine refers to internal combustion engines, usually petrol
engines, where the combustion process of the air-fuel mixture is ignited by a spark
from a spark plug. This is in contrast to compression-ignition engines, typically diesel
engines, where the heat generated from compression is enough to initiate the
combustion process, without needing any external spark.
33
Spark-ignition engines are commonly referred to as "gasoline engines" in America,
and "petrol engines" in Britain and the rest of the world. However, these terms are not
preferred, since spark-ignition engines can (and increasingly are) run on fuels other
than petrol/gasoline, such as auto gas (LPG), methanol, ethanol, bioethanol,
compressed natural gas (CNG), hydrogen, and (in drag racing) nitromethane.
A working cycle consists of four-stroke spark-ignition engine is an Otto cycle engine.
It consists of following four strokes: suction or intake stroke, compression stroke,
expansion or power stroke, exhaust stroke. Each stroke consists of 180 degree rotation
of crankshaft rotation and hence a four-stroke cycle is completed through 720 degree
of crank rotation. Thus, for one complete cycle there is only one power stroke while
the crankshaft turns by two revolutions.
Fig.22 P-V Diagram Ideal Otto Cycle
3.5.3 Diesel engine
Compression Ignition (CI) The combustion process in a CI engine starts when the
air-fuel mixture self-ignites due to high temperature in the combustion chamber
caused by high compression.
34
The diesel engine has the highest thermal efficiency of any standard internal or
external combustion engine due to its very high compression ratio. Low-speed diesel
engines (as used in ships and other applications where overall engine weight is
relatively unimportant) can have a thermal efficiency that exceeds 50%.
Diesel engines are manufactured in two-stroke and four-stroke versions. They were
originally used as a more efficient replacement for stationary steam engines. Since the
1910s they have been used in submarines and ships. Use in locomotives, trucks, heavy
equipment and electric generating plants. Diesel engine based on diesel cycle as shown
in diagram below:
Fig. 23 P-V Diagram diesel cycle
3.5.4 Engine parts
a) Valves
The intake and exhaust valves open at the proper time to let in air and fuel and to let
out exhaust. Note that both valves are closed during compression and combustion so
that the combustion chamber is sealed.
b) Piston
A piston is a cylindrical piece of metal that moves up and down inside the cylinder.
35
c) Piston rings
Piston rings provide a sliding seal between the outer edge of the piston and the inner
edge of the cylinder. The rings serve two purposes They prevent the fuel/air mixture
and exhaust in the combustion chamber from leaking into the sump during
compression and combustion.
They keep oil in the sump from leaking into the combustion area, where it would be
burned and lost. Most cars that "burn oil" and have to have a quart added every 1,000
miles are burning it because the engine is old, and the rings no longer seal things
properly.
d) Connecting rod
The connecting rod connects the piston to the crankshaft. It can rotate at both ends so
that its angle can change as the piston moves and the crankshaft rotates.
e) Crankshaft
The crankshaft turns the piston's up and down motion into circular motion just like a
crank on a jack-in-the-box does.
f) Sump
The sump surrounds the crankshaft. It contains some amount of oil, which collects in
the bottom of the sump (the oil pan).
g) Superchargers and turbochargers
A supercharger and turbochargers are a "forced induction" system which uses a
compressor powered by the shaft of the engine which forces air through the valves of
the engine to achieve higher flow. When these systems are employed the maximum
absolute pressure at the inlet valve is typically around 2 times atmospheric pressure or
more [8].
Fig.24 Turbocharger
36
3.5.5 Engine parameters
a) Indirect injection (IDI): Fuel injection into the secondary chamber of an engine
with a divided combustion chamber.
b) Bore: Diameter of the cylinder or diameter of the piston face, which is the same
minus a very small clearance.
c) Stroke: Movement distance of the piston from one extreme position to the other:
TDC to BDC or BDC to TDC.
d) Clearance: Volume Minimum volume in the combustion chamber with piston at
TDC.
e) Displacement or displacement volume: Volume displaced by the piston as it
travels through one stroke. Displacement can be given for one cylinder or for the
entire engine (one cylinder time number of cylinders). Some literature calls this swept
volume.
Fig.25 Diesel engine with double turbocharger
37
3.5.6 The difference between SI engine and CI engine
a) SI engine spark ignition system ignites the A/F mixture to produce power and not
available in CI engine that depend totally on compression ratio and flash point of
diesel fuel.
b) Fuel injection is direct in CI engine and separated from air, which is different from
SI engine are mixed.
c) In CI engine thermal efficiency, power and torque are higher than SI engine.
d) Compression ratio in CI engine is 8-12, in SI engine around 4-6.
e) Fuel consumption in CI engine is less than SI engine.
f) CI engine used in heavy duties and SI engine used for light duties.
38
Chapter 4
4.1 Crude oil storages
When we drill wells in a productive field and start production, we need to store and/or
transport the fluids to the market. When several oil production wells are present then
connection of surface lines could be made in bundles. At the wellhead the separators
(single or two stages) can be utilized. They are used to separate the remaining gas in
solution by adjusting pressure in the separator. Water is separated due to the gravity
difference. Crude oil is fed into crude oil line and gas is flowed through the gas lines.
The storage of crude oil, refinery products and natural gas is an important subject. It is
needed to store them when they are not used. The necessary conditions must be
satisfied during storing. Crude oil is stored in large tanks after produced. When we
look at an oil field, we can see large storage tanks clustered together in what is called
tank farm.
These may run in size from a few hundred to several thousand barrels capacity,
according to the production of the wells. In the really big tank farms, it is quite
common to see tanks of 55,000 and 80,000 barrels capacity. Other groups of storage
tanks may be seen at key points along pipelines, at ports where oil is loaded on
tankers, and at the refineries to which crude oil goes to be processed for the market.
An enormous amount of crude petroleum is constantly kept stored in such tanks in all
parts of the world. The produced natural gas is liquefied before storage. It is also
stored in underground formations. Natural gas is injected into suitable formations
when market demand is low. Then it is produced when demand is high.
Fig.26 Spherical gas tank farm in the petroleum refinery
39
Reservoirs can be covered; in which case they may be called covered or underground
storage tanks or reservoirs. Covered water tanks are common in urban areas.
4.2 Type of crude oil storages
Storage tanks are available in many shapes: vertical and horizontal cylindrical; open
top and closed top; flat bottom, cone bottom, slope bottom and dish bottom. Large
tanks tend to be vertical cylindrical, or to have rounded corners transition from
vertical side wall to bottom profile, to easier withstand hydraulic hydrostatically
induced pressure of contained liquid. Most container tanks for handling liquids during
transportation are designed to handle varying degrees of pressure. There are two basic
type of oil storage according to roof design:
a) Fixed roof tanks are meant for liquids with very high flash points, (e.g. fuel
oil, water, bitumen etc.) Cone roofs, dome roofs and umbrella roofs are usual.
These are insulated to prevent the clogging of certain materials, wherein the
heat is provided by steam coils within the tanks. Dome roof tanks are meant
for tanks having slightly higher storage pressure than that of atmosphere (e.g.
slop oil), fixed Roof Tank used for diesel, kerosene, catalytic cracker
feedstock, and residual fuel oil.
b) Floating roof tanks are broadly divided into external floating roof tanks
(usually called as floating roof tanks FR Tanks) and internal floating roof
types (IFR Tanks) and used for crude oil, gasoline, and naphtha.
c) Bullet tank used for normal butane, propane, and propylene
d) Spherical tank used for iso-butane and normal-butane.
It is to be noted that fixed roof tanks could be used for storing low amounts of crude
oil as compared to the million barrels stored in floating roof tanks.
4.3 Crude oil storage components
1. Storage body or shell.
2. Stairs.
3. Drain valve.
4. Inlet valve.
5. Outlet valve.
6. Fire system.
7. Pressure relief valve.
8. Pressure gage.
9. Level Trans meter.
40
Fig.27 Fixed roof tank
Fig.28 Floating roof tank
41
Fig.29 Crude oil storage components
42
Chapter 5
5.1 Reactors
Chemical reactors are vessels designed to contain chemical reactions. It is the site of
conversion of raw materials like naphtha, kerosene and other materials into products
ready to use and is also called the heart of a chemical process.
The design of a chemical reactor where the motion of fluid over the catalyst would be
synthetic sized on a commercial scale would depend on multiple aspects of chemical
engineering. The Since it is a very vital step in the overall design of a process,
designers ensure that the reaction proceeds with the highest efficiency towards the
desired output, producing the highest yield of product in the most cost-effective way.
Reactors are designed based on features like mode of operation or types of phases
present or the geometry of reactors. They are thus according to operation of reactor
called:
a) Batch reactors: A process in which all the reactants are added together at the
beginning of the process and products removed at the termination of the reaction
iscalled a batch process. In this process, no addition or withdrawal is made while the
reaction is progressing (Fig. 30). Batch processes are suitable for small production
and for processes where a range of different products or grades is to be produced in
the same equipment for example, pigments, dye stuff and polymers.
b) Semi continues reactors: A Process that do not fit in the definition of batch or a
semi batch reactor is operated with both continuous and batch inputs and outputs and
are often referred to as semi continuous or semi-batch. In such semi-batch reactors,
some of the reactants may be added or some of the products withdrawn as the reaction
proceeds. A semi-continuous process can also be one which is interrupted periodically
for some specific purpose, for example, for the regeneration of catalyst, or for
removal of gas
c) Continuous reactors: A process in which the reactants are fed to the reactor and
the products or byproducts are withdrawn in between while the reaction is still
progressing. For example, Haber Process for the manufacture of Ammonia.
Continuous production will normally give lower production costs as compared to
batch production, but it faces the limitation of lacking the flexibility of batch
production. Continuous reactors are usually preferred for large scale production.
43
Fig.30 Chemical reactors
5.2 Type of reactors according to phase
a) Homogenous phase: Homogeneous reactions are those in which the reactants,
products and any catalyst used form one continuous phase; for example, gaseous or
liquid. Homogeneous gas phase reactors will always be operated continuously.
Tubular (Pipeline) reactors are normally used for homogeneous gas phase reactions,
for example, in the thermal cracking of petroleum, crude oil fractions to ethylene.
Homogeneous liquid phase reactors may be batch or continuous.
b) Heterogeneous phase: In a heterogeneous reaction two or more phases exist and
the overriding problems in the reactor design is to promote mass transfer between the
phases.
44
5.3 Type of reactor according to design
a) Stirred Tank Reactor: The stirred tank reactor can be considered the basic
chemical reactor, modeling on a large scale. Tank sizes range from a few liters to
several thousand liters.
b) Tubular Reactor: Tubular reactors are generally used for gaseous reactions but are
also suitable for some liquid phase reactions. If high heat transfer rates are required
small diameter tubes are used to increase the surface area to volume ratio.
c) Packed Bed Reactor: Industrial packed bed catalytic reactors range in size from
small tubes, a few centimeters diameter to large diameter packed beds. Packed bed
reactors are used for gas and gas liquid reactions. Heat transfer rates in large
diameter packed beds are poor therefore, where high heat-transfer rates are
required, fluidized beds should be considered.
d) Fluidized Bed Reactor: A fluidized bed reactor is a combination of the two most
common, packed beds and stirred tank, continuous flow reactors. It is very
important to chemical engineering because of its excellent heat and mass transfer
characteristics.
5.4 Catalyst
Catalysis is the increase in the rate of a chemical reaction of one or more reactants due
to the participation of an additional substance called a catalyst. Unlike other reagents
in the chemical reaction, a catalyst is not consumed by the reaction. With a catalyst,
less free energy is required to reach the transition state, but the total free energy from
reactants to products does not change. A catalyst may participate in multiple chemical
transformations. The effect of a catalyst may vary due to the presence of other
substances known as inhibitors or poisons (which reduce the catalytic activity) or
promoters (which increase the activity). The opposite of a catalyst, a substance that
reduces the rate of a reaction, is an inhibitor.
Catalyzed reactions have lower activation energy (rate limiting free energy of
activation) than the corresponding un-catalyzed reaction, resulting in a higher reaction
rate at the same temperature and for the same reactant concentrations. However, the
mechanistic explanation of catalysis is complex. Catalysts may affect the reaction
environment favorably, or bind to the reagents to polarize bonds, e.g. acid catalysts
for reactions of carbonyl compounds, or form specific intermediates that are not
produced naturally, such as platinum or rhenium in catalytic hydrogenation.
45
Kinetically, catalytic reactions are typical chemical reactions, i.e., the reaction rate
depends on the frequency of contact of the reactants in the rate determining step.
Usually, the catalyst participates in this slowest step, and rates are limited by amount
of catalyst and its "activity". In heterogeneous catalysis, the diffusion of reagents to
the surface and diffusion of products from the surface can be rate determining. A
nanomaterial-based catalyst is an example of a heterogeneous catalyst. Analogous
events associated with substrate binding and product dissociation apply to
homogeneous catalysts.
Although catalysts are not consumed by the reaction itself, they may be inhibited,
deactivated, or destroyed by secondary processes. In heterogeneous catalysis, typical
secondary processes include coking where the catalyst becomes covered by polymeric
side products. Additionally, heterogeneous catalysts can dissolve into the solution in a
solid - liquid system or sublimate in a solid–gas system.
Fig. 31 Reactors in reformer unit
46
5.5 Reactor design
In the chemical industry, proper reactor design is crucial because this is where both
mixing, and reaction occur. For a mixing sensitive reaction, the rate of mixing affects
both the yield and selectivity of the reaction.
Poor mixing can lead to side reactions and undesirable by products in competitive
reactions.
A common industrial example of this is acid/base neutralization in the presence of
organic substrates. Rapid, highly turbulent mixings needed to promote the
fast-reacting neutralization reaction and inhibit the slower, unwanted side reactions
such as hydrolysis.
There are many react, or geometries used in the chemical industry, but discussion will
be limited to four geometries: pipeline, Tee mixer, static mixer, and stirred tank.
Additionally, the effect of feed point location will be discussed.
A pipe, or tubular reactor, is the simplest chemical reactor. Reactants are injected in
one end and allowed to mix as they flow towards the outlet. Often injection is done
with a co-axial jet in the center of the pipe.
Turbulent flow requires approximately 50 to 100 pipe diameters to achieve 95%
Uniformity within the pipeline. This option is often used successfully in highly
turbulent flow where mixing length and time are not important.
Fig.32 Chemical reactor
47
Chapter 6
6.1 Heating, ventilation and air conditioning [HVAC]
The heat, ventilation and air conditioning system (HVAC) feeds conditioned air to the
equipment and accommodation rooms, etc. Cooling and heating are achieved by
water-cooled or water/steam-heated heat exchangers. Heat may also be taken from gas
turbine exhaust. In tropical and sub-tropical areas, cooling is achieved by compressor
refrigeration units. In tropical areas, gas turbine inlet air must be cooled to achieve
sufficient efficiency and performance. The HVAC system is usually delivered as one
package and may also include air emissions cleaning. Some HVAC subsystems
include:
a) Cool: cooling medium, refrigeration system, freezing system
b) Heat: heat medium system, hot oil system
One function is to provide air to equipment rooms that are secured by positive
pressure. This prevents potential influx of explosive gases in case of a leak.
c) Ventilating
Is the process of "changing" or replacing air in any space to provide high indoor air
quality (i.e. to control temperature, replenish oxygen, or remove moisture, odors,
smoke, heat, dust, airborne bacteria, and carbon dioxide). Ventilation is used to
remove unpleasant smells and excessive moisture, introduce outside air, to keep
interior building air circulating, and to prevent stagnation of the interior air [9].
Fig.33 HVAC system
48
6.2 Refrigeration cycle
The vapor compression refrigeration cycle is a common method for transferring heat
from a low temperature to a high temperature. The above figure shows the
objectives of refrigerators and heat pumps. The purpose of a refrigerator is the
removal of heat, called the cooling load, from a low-temperature medium.
The purpose of a heat pump is the transfer of heat to a high-temperature medium,
called the heating load. When we are interested in the heat energy removed from a
low-temperature space, the device is called a refrigerator. When we are interested in
the heat energy supplied to the high-temperature space, the device is called a heat
pump. In general, the term heat pump is used to describe the cycle as heat energy is
removed from the low-temperature space and rejected to the high temperature space.
The performance of refrigerators and heat pumps is expressed in terms of
Coefficient of Performance (COP).
Refrigeration systems are also rated in terms of tons of refrigeration. One ton of
refrigeration is equivalent to 12,000 Btu/hr or 211 kJ/min. How did the term “ton of
cooling” originate?
Reversed Carnot Refrigerator and Heat Pump shown below are the cyclic
refrigeration device operating between two constant temperature reservoirs and the
T-s diagram for the working fluid when the reversed Carnot cycle is used. Recall
that in the Carnot cycle heat transfers take place at constant temperature. If our
interest is the cooling load, the cycle is called the Carnot refrigerator. If our interest
is the heat load, the cycle is called the Carnot heat pump.
Fig.34 Refrigration cycle
The vapor-compression refrigeration cycle has four components: evaporator,
compressor, condenser, and expansion (or throttle) valve. The most widely used
refrigeration cycle is the vapor-compression refrigeration cycle.
49
In an ideal vapor-compression refrigeration cycle, the refrigerant enters the
compressor as a saturated vapor and is cooled to the saturated liquid state in the
condenser. It is then throttled to the evaporator pressure and vaporizes as it absorbs
heat from the refrigerated space. The ideal vapor-compression cycle consists of four
processes.
Fig.35 The vapor-compression refrigeration cycle
6.2.1 Ideal vapor-compression refrigeration cycle process description
1-2 Isentropic compression
2-3 Constant pressure heat rejection in the condenser
3-4 Throttling in an expansion valve
4-1 Constant pressure heat addition in the evaporator
50
Fig.36 Expansion valve in refrigeration system
To increase the [COP] of the cycle, increase the evaporation temperature or decrease
the condensing temperature. However, you can’t achieve as cold of a temperature now,
and your heat exchanger will need to be larger since temperature difference is smaller,
2-4% increase in [COP] per degree temperature change.

   
  
 …………………… (1)
 
   
  
 …………………… (2)
   …………………… (3)
51
Chapter 7
7.1 Upstream process sections in oil and gas location
We will go through each section in detail in the following chapters. The summary
below is an introductory synopsis of each section. The activities up to the producing
wellhead (drilling, casing, completion and wellhead) are often called “pre-completion,”
while the production facility is “post-completion.” For conventional fields, they tend
to be roughly the same in initial capital expenditure.
7.1.1 Wellheads
The wellhead sits on top of the actual oil or gas well leading down to the reservoir. A
wellhead may also be an injection well, used to inject water or gas back into the
reservoir to maintain pressure and levels to maximize production.
Fig.37 Wellheads
Once a natural gas or oil well is drilled and it has been verified that commercially
viable quantities of natural gas are present for extraction, the well must be “completed”
to allow petroleum or natural gas to flow out of the formation and up to the surface.
This process includes strengthening the well hole with casing, evaluating the pressure
and temperature of the formation, and installing the proper equipment to ensure an
52
efficient flow of natural gas from the well. The well flow is controlled with a choke.
We differentiate between, dry completion (which is either onshore or on the deck of
an offshore structure) and subsea completions below the surface.
The wellhead structure, often called a Christmas tree, must allow for a number of
operations relating to production and well work over. Well work over refers to various
technologies for maintaining the well and improving its production capacity.
7.1.2 Manifolds
Onshore, the individual well streams are brought into the main production facilities
over a network of gathering pipelines and manifold systems. The purpose of these
pipelines is to allow setup of production "well sets" so that for a given production
level, the best reservoir utilization well flow composition (gas, oil, water), etc., can be
selected from the available wells.
For gas gathering systems, it is common to meter the individual gathering lines into
the manifold as shown in this picture. For multiphase flows (combination of gas, oil
and water), the high cost of multiphase flow meters often leads to the use of software
flow rate estimators that use well test data to calculate actual flow.
Offshore, the dry completion wells on the main field center feed directly into
production manifolds, while outlying wellhead towers and subsea installations feed
via multiphase pipelines back to the production risers.
Risers are a system that allows a pipeline to "rise" up to the topside structure. For
floating structures, this involves a way to take up weight and movement. For heavy
crude and in Arctic areas, diluents and heating may be needed to reduce viscosity and
allow flow.
Fig.38 Manifolds and gathering
53
7.1.3 Separation
Some wells have pure gas production which can be taken directly for gas treatment
and/or compression. More often, the well produces a combination of gas, oil and
water, with various contaminants that must be separated and processed.
The production separators come in many forms and designs, with the classic variant
being the gravity separator. In gravity separation, the well flow is fed into a horizontal
vessel. The retention period is typically five minutes, allowing gas to bubble out,
water to settle at the bottom and oil to be taken out in the middle. The pressure is
often reduced in several stages (high pressure separator, low pressure separator, etc.)
to allow controlled separation of volatile components. A sudden pressure reduction
might allow flash vaporization leading to instability and safety hazards [10].
Fig.39 Crude oil separator
7.1.4 Metering, storage and export
Most plants do not allow local gas storage, but oil is often stored before loading
on a vessel, such as shuttle tanker taking oil to a larger tanker terminal, or direct to
a crude carrier. Offshore production facilities without a direct pipeline connection
generally rely on crude storage in the base or hull, allowing a shuttle tanker to
offload about once a week. A larger production complex generally has an
associated tank farm terminal allowing the storage of different grades of crude to
take up changes in demand, delays in transport, etc.
Metering stations allow operators to monitor and manage the natural gas and oil
exported from the production installation. These employ specialized meters to
measure the natural gas or oil as it flows through the pipeline, without impeding
its movement. This metered volume represents a transfer of ownership from a
producer to a customer (or another division within the company) and is called
custody transfer metering. It forms the basis for invoicing the sold product and
54
also for production taxes and revenue sharing between partners.
Accuracy requirements are often set by governmental authorities. Typically, a
metering installation consists of a number of meters runs so that one meter will
not have to handle the full capacity range and associated proved loops so that the
meter accuracy can be tested and calibrated at regular intervals.
Fig.40 Tank storage and transportation
7.1.5 Utility systems
Utility systems are systems which do not handle the hydrocarbon process flow but
provide some service to the main process safety or residents.
Depending on the location of the installation, many such functions may be available
from nearby infrastructure, such as electricity. Many remote installations are fully
self-sustaining and must generate their own power, water, etc.
Fig.41 Circulation system
55
Units
Some common units used in the industries are listed here as a representative selection
of US and metric units, since both are used in different parts of the industries. The
non-standard factors differ slightly between different sources.
API American Petroleum Institute crude grade
API = (141.5 / Specific gravity) – 131.5
Spec gravity = 141.5/(API + 131.5) kg/l
Bl Barrel (of oil) 1 Bl = 42 Gallons
1 Bl = 159 liters
1 Bl equiv. to 5487 scf = 147 scm gas
Bpd Barrel per day 1 Bpd ≈ 50 tons/tons per year
BTU British thermal unit 1 BTU = 0.293 Wh = 1,055 kJ
Cal Calorie 1 Cal = 4,187 J (Joules)
MMscf Million standard cubic feet
1 MMscf = 23.8 TOE ≈ 174 barrels
psi Pounds per square-inch
1 psi = 6.9 kPa = 0.069 atm
Scf Standard cubic feet (of gas) defined by energy, not a normalized volume
1 scf = 1000 BTU = 252 kcal = 293 Wh = 1,055 MJ ≈ 0.0268 scm
Scm Standard cubic meter (of gas, also Ncm) Defined by energy content
1 Scm = 39 MJ = 10.8 kWh
1 Scm ≈ 37.33 Scf (not a volume conv.)
1 Scm ≈ 1.122 kg
TOE Tons oil equivalent Range 6.6 - 8 barrels at API range 8 - 52
1 TOE = 1000 kg = 1 Ton (metric) oil
1 TOE = 1 Tone oil (US)
1 TOE ≈ 7.33 Barrels (at 33 API)
1 TOE ≈ 42.9 GJ =11,9 MWh
1 TOE ≈ 40.6 MMBTU
1 TOE ≈ 1.51 ton of coal
1 TOE ≈ 0.79 ton LNG
1 TOE ≈ 1,125 Scm = 42,000 Scf
kWh Kilowatt hour= 1000 joules * 3600 S
1 kWh = 3.6 MJ = 860 kcal = 3,413 BTU
56
References
[1] Johann Friedrich Gülich (2010) Centrifugal Pumps, Springer-Verlag Berlin
Heidelberg. https://doi.org/10.1007/978-3-642-12824-0.
[2] Kurzke J., Halliwell I. (2018) Compressors. In: Propulsion and Power. Springer,
Cham. https://doi.org/10.1007/978-3-319-75979-1_9.
[3] Mohamad B., Szepesi G.L., Bollo B. (2018) Review Article: Effect of
Ethanol-Gasoline Fuel Blends on the Exhaust Emissions and Characteristics of
SI Engines. In: Jármai K., Bolló B. (eds) Vehicle and Automotive Engineering 2.
VAE 2018. Lecture Notes in Mechanical Engineering. Springer, Cham.
https://doi.org/10.1007/978-3-319-75677-6_3.
[4] Mohamad B., Szepesi G., Bollo B. (2017) Combustion Optimization in Spark
Ignition Engines, MultiScience - XXXI. microCAD International
Multidisciplinary Scientific Conference.
[5] Amroune S., Belaadi A., Menasri N., Zaoui M., Mohamad B., Amin H. (2019)
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Diagnostyka, 20 (4): 95-101. https://doi.org/10.29354/diag/114621.
[6] Мохамед Б, Кароли Я, Зеленцов А.А. (2020) Трехмерное моделирование
течения газа во впускной системе автомобиля «формулы студент» Журнал
Сибирского федерального университета, 13(5); pp. 597-610.
https://doi.org/10.17516/1999-494X-0249.
[7] Mohamad B., Karoly J., Zelentsov A.A. (2020) Hangtompító akusztikai tervezése
hibrid módszerrel, Multidiszciplináris Tudományok, 9(4), pp. 548-555.
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This book gives an unparalleled, up-to-date, in-depth treatment of all kinds of flow phenomena encountered in centrifugal pumps including the complex interactions of fluid flow with vibrations and wear of materials. The scope includes all aspects of hydraulic design, 3D-flow phenomena and partload operation, cavitation, numerical flow calculations, hydraulic forces, pressure pulsations, noise, pump vibrations (notably bearing housing vibration diagnostics and remedies), pipe vibrations, pump characteristics and pump operation, design of intake structures, the effects of highly viscous flows, pumping of gas-liquid mixtures, hydraulic transport of solids, fatigue damage to impellers or diffusers, material selection under the aspects of fatigue, corrosion, erosion-corrosion or hydro-abrasive wear, pump selection, and hydraulic quality criteria. The 2nd ed. has been enhanced by hydraulic design information on axial pumps and sewage pumps, turbine performance curve prediction, torsional rotor vibrations and recent research results on partload flow and hydraulic excitation forces. To ease the use of the information, the methods and procedures for the various calculations and failure diagnostics discussed in the text are gathered in about 150 pages of tables which may be considered as almost unique in the open literature. The text focuses on practical application in the industry and is free of mathematical or theoretical ballast. In order to find viable solutions in practice, the physical mechanisms involved should be thoroughly understood. The book is focused on fostering this understanding which will benefit the pump engineer in industry as well as academia and students.
Трехмерное моделирование течения газа во впускной системе автомобиля «формулы студент» Журнал Сибирского федерального университета
  • Б Мохамед
  • Я Кароли
  • А А Зеленцов
Мохамед Б, Кароли Я, Зеленцов А.А. (2020) Трехмерное моделирование течения газа во впускной системе автомобиля «формулы студент» Журнал Сибирского федерального университета, 13(5);