Study of refrigeration unit & boilers. It involved the calculation of safe chimney height required to dispose the smoke out into atmosphere without polluting the land and the estimation of fuel amount required for an oil fired boiler per day in HIL, Rasayani.

1. 1
INDUSTRIAL TRAINING REPORT AT
HINDUSTAN INSECTICIDE LIMITED
(A Government of India Enterprise)
RASAYANI
“working of Mechanical equipments in the plant”
Submitted to
University of Pune
BY
Miss. Akansha Jha
(B.E Mechanical)
Under the guidance of
Mr. R.K. Nagpal
(MANAGER TECHNICAL SERVICES)
AMRUTVAHINI COLLEGE OF ENGINEERING, SANGAMNER

2. 2
HINDUSTAN INSECTICIDES LTD
RASAYANI PLANT
CERTIFICATE
This is to certify that Miss. Akansha Jha, a student of III
year, mechanical department, Amrutvahini College Of
Engg., Sangamner has undergone a 15 days Industrial
Training and completed the implant training report on
‘Working of Mechanical equipments in the plant’.
Mr.J.A.Paliwal Mr. R.K.Nagpal
Training Officer Manager Technical Services
HIL, Rasayani HIL, Rasayani
(Mentor) (Head of Training Dept)

3. 3
ACKNOWLEDGEMENT
I am here by submitting a report on the completion of project at
Hindustan Insecticides Ltd. during the period of 15 days. I offer my
profound gratitude to the management of Hindustan Insecticides
Ltd. Providing me an opportunity to undergo such a simulative
training in the most estimated organization.
I would like to thanks Mr. R.K. Nagpal (MTS) & Mr. J.A Paliwal
(Training Officer) & all other plant supervisors for their valuable
co-operation & guidance during apologies are extended to those
people whose names are not mentioned above but their
contribution cannot be overlooked.

4. 4
INTRODUCTION ABOUT HIL
Hindustan Insecticides Limited (HIL) is a Government of India enterprise under the
Ministry of Chemicals and Fertilizers. It was incorporated in March 1954 in order to start
production of DDT for the National Malaria Eradication Programme. Since then its
product range has expanded to include Insecticides, Herbicides, Weedecides, and
Fungicides.
HIL is the world's largest producer of DDT. The company has three manufacturing units,
located at Udyogamandal, near Cochin (Southern India) and Rasayani near
Mumbai(Western India) and Bathinda in Punjab (Northern India).
The operation of the unit started in the year 1980 mainly to cater the demand of National
Vector Borne Disease Control Program (NVBDCP). HIL is ISO 9001:2008,ISO
14001:2004, and OHSAS 18001:2007 certified company.
Manufacturing activity is well supported by engineers, experienced plant operators and
quality assurance personals.

5. 5
TABLE OF CONTENTS
Chapter Title Page No.
Introduction About HIL 1
1 Utility: Refrigeration System 2
1.1 Refrigerant Section 2
1.2 Refrigeration Cycle 3
1.3 High And Low Pressure Sides Of The Refrigeration
Plant
7
2 Centrifugal Pump 7
2.1 Hydraulic Component 8
3 Boilers 9
3.1 Classification Of Boiler 10
3.2 Maintaining Your Boiler: Three Essential Elements 14
3.3 Boiler Terms 17
3.4 Boiler Mountings And Accessories 19
3.5 Boiler Information 21
3.6 Causes Of Boiler Accidents 21
3.7 Boiler Inspections 22
3.8 Concept Of Equivalent Evaporation 24
3.9 Boiler Efficiency 24
3.10 Boiler Do’s And Don’ts 26
3.11 Calculations On Boilers 27

6. 6
1 UTILITY: REFRIGERATION SYSTEM[1]
The job of a refrigeration plant is to cool articles or substances down to, and maintain
them at a temperature lower than the ambient temperature. Refrigeration can be defined
as a process that removes heat.
Fig 1.1 Typical refrigeration system
1.1 REFRIGERANT SECTION
The main function of any refrigeration system is to cool given substance. The amount of
refrigeration is measured in term of tons is defined quantity of a system in which it
remove heat at the rate of 210 kg/min. In the chemical plant refrigeration is required for
two purpose:
1) Some chemical reaction takes place below room temperature.
2) Some chemical reaction are exothermic. In order to keep the temperature at
desired value, heat is to be removed from reactor, which is done by refrigeration
system.
Here production of DDT technical at (-10C) and for MCB technical is at (-50C).This Low
temperature achieved by refrigeration system. Commonly used refrigerant are

7. 7
NH3,R22,R11,brine(CaCl2 )etc. In this plant R22 used as primary refrigerant and brine as
secondary refrigerant. There are two types of refrigeration system:
a) Vapours absorption system.
b) Vapours compression system.
Refrigeration R22 has low specific volume and hence it will reduced the size of the plant
compared to others, which is suitable for industrial purpose. The different refrigeration
units in this company are 100 TR & 200 TR. Specifications of the system are:
a) 100TR plan
 Compressor-Voltas
 Condenser and evaporation-shell tube type
 Expansion valve
b) 200TR
 Compressor-Kirlosker
 Expansion device-thermostatic expansion
1.2 REFRIGERATION CYCLE
Fig 1.2 Refrigeration cycle

8. 8
The main component of refrigeration are as follows:
 Compressor
 Evaporator
 Expansion Device
 Condenser
1.2.1 Evaporator
A refrigerant in liquid form will absorb heat when it evaporates and it is this conditional
change that produces cooling in a refrigerating process. If a refrigerant at the same
temperature as ambient is allowed to expand through a hose with an outlet to atmospheric
pressure, heat will be taken up from the surrounding air and evaporation will occur at a
temperature corresponding to atmospheric pressure. If in a certain situation pressure on
the outlet side (atmospheric pressure) is changed, a different temperature will be obtained
since this is analogous to the original temperature it is pressure dependent. The
component where this occurs is the evaporator, whose job it is to remove heat from the
surroundings, i.e. to produce refrigeration.
Fig 1.2.1 Evaporator
1.2.2 Compressor
The refrigeration process is, as implied, a closed circuit. The refrigerant is not allowed to
expand to free air. When the refrigerant coming from the evaporator is fed to a tank the
pressure in the tank will rise until it equals the pressure in the evaporator. Therefore,
refrigerant flow will cease and the temperature in both tank and evaporator will gradually

9. 9
rise to ambient. To maintain a lower pressure, and, with it a lower temperature it is
necessary to remove vapour. This is done by the compressor, which sucks vapour away
from the evaporator.
Fig 1.2.2 Compressor
In simple terms, the compressor can be compared to a pump that conveys vapour in the
refrigeration circuit. In a closed circuit a condition of equilibrium will always prevail. To
illustrate this, if the compressor sucks vapour away faster than it can be formed in the
evaporator the pressure will fall and with it the temperature in the evaporator. Conversely,
if the load on the evaporator rises and the refrigerant evaporates quicker, the pressure and
with it the temperature in the evaporator will rise.
1.2.3 Condenser
The refrigerant gives off heat in the condenser, and this heat is transferred to a medium
having a lower temperature. The amount of heat given off is the heat absorbed by the
refrigerant in the evaporator plus the heat created by compression input. The heat transfer
medium can be air or water, the only requirement being that the temperature is lower than
that which corresponds to the condensing pressure. The process in the condenser can
otherwise be compared with the process in the evaporator except that it has the opposite
“sign”, i.e. the conditional change is from vapour to liquid. The heat transfer medium can
be air or water, the only requirement being that the temperature is lower than that which
corresponds to the condensing pressure. The process in the condenser can otherwise be
compared with the process in the evaporator except that it has the opposite “sign”, i.e. the
conditional change is from vapour to liquid.

10. 10
Fig 1.2.3 Condenser
1.2.4 Expansion process
Liquid from the condenser runs to a collecting tank, the receiver. This can be likened to
the tank mentioned under section 3.1 on the evaporator. Pressure in the receiver is much
higher than the pressure in the evaporator because of the compression (pressure increase)
that has occurred in the compressor. To reduce pressure to the same level as the
evaporating pressure a device must be inserted to carry out this process, which is called
throttling, or expansion. Such a device is therefore known either as a throttling device or
an expansion device. As a rule a valve is used – a throttle or expansion valve.
Fig 1.2.4 Expansion Valve

11. 11
Ahead of the expansion valve the liquid will be a little under boiling point. By suddenly
reducing pressure a conditional change will occur; the liquid begins to boil and evaporate.
This evaporation takes place in the evaporator and the circuit
is thus complete.
1.3 HIGH AND LOW PRESSURE SIDES OF THE REFRIGERATION PLANT:
There are many different temperatures involved in the operation of a refrigeration plant
since there are such things as subcooled liquid, saturated liquid, saturated vapour and
superheated vapour. There are however, in principle, only two pressures; evaporating
pressure and condensing pressure. The plant then is divided into high pressure and low
pressure sides, as shown in the sketch.
Fig 1.3 Refrigeration pressure sides
2 CENTRIFUGAL PUMP[2]
Principle Of Centrifugal Pump: An increase in the fluid pressure from the pump inlet to
its outlet is created when the pump is in operation. This pressure difference drives the
fluid through the system or plant.
The centrifugal pump creates an increase in pressure by transferring mechanical
energy from the motor to the fluid through the rotating impeller. The fluid flows from the
inlet to the impeller centre and out along its blades. The centrifugal force hereby increases
the fluid velocity and consequently also the kinetic energy is transformed to pressure.
Figure shows an example of the fluid path through the centrifugal pump.

12. 12
Fig 2.1 Principle of operation
Fig 2.2 Centrifugal pump
2.1 HYDRAULIC COMPONENT
The principles of the hydraulic components are common for most centrifugal pumps. The
hydraulic components are the parts in contact with the fluid. Fig 2.3 shows the hydraulic
components in a single-stage inline pump. The subsequent sections describe the
components from the inlet flange to the outlet flange.

13. 13
Fig 2.3 Hydraulic Components of Centrifugal pump
3 BOILER
A boiler is a vessel or zone in which heat is generated with the help of fuel and
transferred to any other material like water, sodiun or heating up of gasses. Its a heating
zone thus is the most critical portion in any industry whether its a gas plant, nuclear plant
or electric plant. So the safety of boiler is the most important concern of any industry. In
the industries there is proper codes and standards for the boiler and one have to follow
these codes for proper using of boilers. As well as companies have to have various
certification also for Boilers.[3] Steam generator or boiler as per Indian Boiler actis a
closed pressure vessel used for generation of steam under pressure.[4]

14. 14
Fig 3.1 Schematic diagram of a Boiler Room
3.1 CLASSIFICATION OF BOILER[5]
3.1.1 Horizontal, Vertical or Inclined Boiler
If the axis of the boiler is horizontal, the boiler is called horizontal, if the axis is vertical,
it is called vertical boiler and if the axis is inclined it is called as inclined boiler. The parts
of horizontal boiler is can be inspected and repaired easily but it occupies more space.
The vertical boiler occupies less floor area.
3.1.2 Fire Tube and Water Tube
In the fire boilers, the hot gases are inside the tubes and the water surrounds the tubes.
Fire tube boilers are generally used for relatively small steam capacities and low to
medium Steam pressures. As a guideline, fire Tube boilers are competitive for steam
Rates up to 12,000 kg/hour and Pressures up to 18 kg/cm2. Fire tube Boilers are available

15. 15
for operation With oil, gas or solid fuels. For Economic reasons, most fire tube Boilers
are of “packaged” construction (i.e. Manufacturer erected) for all fuels.
Examples: Cochran, Lancashire and Locomotive boilers.
Fig. 3.1.1 Fire tube boiler
In the water tube boilers, the water is inside the tubes and hot gases surround them. The
circulated water is heated by the combustion gases and converted into steam at the vapour
space in the drum. These boilers are selected when the steam demand as well as steam
pressure requirements are high as in the case of process cum power boiler / power boilers.
Most modern water boiler tube designs are within the capacity range 4,500 – 120,000
kg/hour of steam, at very high pressures. Many water tube boilers are of “packaged”
construction if oil and /or gas are to be used as fuel. Solid fuel fired water tube designs
are available but packaged designs are less common. The features of water tube boilers
are:
 Forced, induced and balanced draft provisions help to improve combustion
efficiency.
 Less tolerance for water quality calls for water treatment plant.
 Higher thermal efficiency levels are possible
Examples: Babcock and Wilcox, Stirling, Yarrow boiler etc.

16. 16
Fig 3.1.2 Simple Diagram of Water Tube Boiler
3.1.3 Externally Fired and Internally Fired
The boiler is known as externally fired if the fire is outside the shell.
Examples: Babcock and Wilcox boiler,Stirling boiler etc.
In case of internally fired boilers, the furnace is located inside the shell.
Examples: Cochran, Lancashire boiler etc.
3.1.4 Higher Pressure and Low Pressure Boilers
The boiler which produce steam at pressures of 80 bar and above are called high pressure
boilers.
Examples: Babcock and Wilcox, Velox,Lamomt,Benson Boiler etc.
The boilers which produce steam at pressure below 80 bar are called low pressure boilers.
Examples: Cochran, Cornish, Lancashire and Locomotive boiler etc.
3.1.5 Forced circulation and Natural Circulation
In forced circulation type of boilers, the circulation of water is done by a forced pump.
Examples: Velox,Lamomt,Benson Boiler etc.
In natural circulation type of boilers, circulation of water in the boiler takes place due to
natural convention currents produced by the application of heat.
Examples: Lancashire, Babcock and Wilcox boiler etc.

17. 17
Fig 3.1.3 Forced circulation in water tube boiler
Fig 3.1.4 Natural circulation in water tube boiler
3.1.6 Stationary and Portable
• Primarily, the boilers are classified as either stationary or mobile.
• Stationary boilers are used for power plant steam, for central station utility power plants,
for plant process steam etc.

18. 18
• Mobile boilers or portable boilers include locomotive type, and other small units for
temporary use at sites.
3.1.7 Single Tube and Multi Tube Boiler
The fire tube boilers are classified as single tube and multi-tube boilers, depending upon
whether the fire tube is one or more than one.
Examples: Cornish ,simple vertical boiler are the single tube boiler and rest of the boilers
are multi-tube boiler.
3.2 MAINTAINING YOUR BOILER: THREE ESSENTIAL ELEMENTS[6]
Whether powered by electricity or fuel, boilers can be a handy heating solution in both
small and large facilities. But a little diligence is required for them to work at their peak
function. Check out these three essential elements of a good boiler maintenance program.
3.2.1 Boiler water treatment
Boiler system (steam/water) loses water through steam and water leaks. Additional water
called “make-up water” is added to the boiler to replace these losses. The amount of
make-up water and the level of naturally occurring impurities in water will determine the
type of water treatment required. Boiler heating systems that have very few leaks will
require a simple water treatment program. Your boiler water treatment professional can
assist you in developing an effective water treatment program.
All water contains dissolved minerals and these minerals, if allowed to reach high
enough levels in the boiler water, will come out of solutions and form as a hard shell on
the hot surfaces of the boiler. This hard shell is called “scale” and is often found on the
outside of the fire tubes or the inside of water tubes. Scale insulates the heating surfaces
reducing the ability of the fire tubes to transfer heat from the hot combustion to the boiler
water. High stack temperatures or ruptured tubes are common problems related to scale
build up. Boiler water also contains dissolved gases such as oxygen or carbon dioxide.
These gases, in the presence of water and metal, can cause corrosion. Corrosion eats away
the metal affecting the durability of the boiler.

19. 19
Fig 3.2.1 Boiler water treatment system
It’s important to remove as much oxygen as possible from the water in the boiler because
oxygen will attack the metal tubing inside and shorten the life of the equipment, says
Roll. Sodium sulfite is one commonly used oxygen scavenger. “The oxygen molecules
attach to the sodium sulfite and it’s rendered harmless,”.
The water inside the boiler should also be sampled regularly and tested to ensure a
proper balance of chemicals and the correct pH. The ideal pH for most boilers is 7, which
is neutral. In certain systems, such as those used for hot water, once-a-month water
sampling may be adequate. However, the water quality in most boilers should be checked
daily.
If you are uncertain about the amount or types of chemicals that should be in the
boiler’s water system, hire a water treatment company. Reputable water treatment
companies can train employees on water quality testing, provide chemicals and return
periodically for troubleshooting. Using a water treatment company also leaves less room
for potentially expensive employee errors.
3.2.2 Safety Checks
Boilers are equipped with numerous safeguards to minimize hazards, so it’s important to
make sure they’re working properly. One of these safeties is the low-water cutoff, which
cuts off the boiler’s power or ignition source when water drops to an unsafe level. “The
flame or ignition source will shut down and prevent a catastrophe,”. Most boilers have a

20. 20
manual valve on the water column, which allows the operator to simulate low-water
conditions. If shutdown doesn’t occur, then further inspection – and repairs – may be
necessary. The low-water cut-off should be tested daily, though in larger facilities, it may
need to be checked out once per shift.
Another safety function (especially in fuel-fired boilers) is the flame safeguard,
which makes sure that the boiler’s pilot light is on before opening the main fuel valve. It
also ensures that the fuel valves close when the pilot light goes out. If this safeguard is not
working properly, the boiler’s combustion chamber can be flooded with raw fuel, Roll
says. Operators can check the flame safeguard by simply observing the boiler as it cycles.
In addition to these daily checks, all electrical circuitry and safeties on a boiler
should be inspected and tested two to four times per year. “A good technician would
check out the circuitry, sequencing, and make sure all electrical components are operating
as they should,” .
3.2.3 Combustion Efficiency
If you are maintaining a fuel-fired boiler, a periodic combustion efficiency analysis is
needed to ensure a proper balance of air and fuel in the burner. This improves efficiency
and ensures that building managers are “getting the biggest bang for their BTU buck,”.
This can be done by a reputable mechanical contractor – most have combustion efficiency
experts on staff.
Many boiler operators have no idea how inefficiently their equipment is running
until an analysis is performed. “Some are rated as having 10 to 15 percent excess air.
“That’s huge.” Too much air will make the burner’s flame go out, while too little air
causes it to “run rich,” leading to excess fumes, unburned fuel and reduced thermal
efficiency.
Ideally, combustion efficiency analysis is performed during the height of the
heating season, when the boiler is running at fully rated capacity. “It’s best when you
have a full load on the boiler and can run the boiler to all of its firing points. Another
analysis can also be done just before the weather turns cold, to head off potential
problems before they star

21. 21
Figure 11. Energy balance diagram of a boiler
3.3 BOILER TERMS[7]
Shell: The shell of a boiler consists of one or more steel plates bents into a cylindrical
form and riveted or welded together. The shell ends are closed with the end plates.
Setting: The primary function of setting is to confine heat to the boiler and form a passage
for gases. It is made of brick work and may form the wall of furnace and the combustion
chamber. It also provides support in some type of boilers(eg. Lancashire boiler).
Grate: It is the platform in the furnace upon which fuel is burnt and it is made of cast iron
bars. The bars are so arranged that air may pass on to the fuel for combustion. The area of
the grate on which the fire rests in a coal or wood fired boiler is called grate surface.
Furnace: It is a chamber formed by the space above the grate and below the boiler shell,
in which combustion takes place. It is also called fire-box. Water space and steam space:
The volume of the shell that is occupied by the water is termed water space while the
entire shell volume less the water and tubes space is called steam space.
Mountings: The items such as stop valve, safety valves, water level gauges, fusible plug,
blow off cock, pressure gauges, water level indicator etc are termed as mounting and
boiler can not work safely without them.

22. 22
Accessories: The items such as super heaters, economizers, feed pumps etc. are termed as
accessories and they form integral part of the boiler. They increase the efficiency of the
boiler.
Water Level: The level at which water stands in the boiler is called water level. The space
above the water level is called steam space.
Foaming: Formation of steam bubbles on the surface of boiler water due to high surface
tension of the water.
Scale: A deposit of medium to extreme hardness occurring on water heating surface.
Blowing off: The removal of the mud and other impurities of water from the lowest part
of the boiler is termed as ‘blowing off’. This is accomplished with the help of blow off
cock or valve.
Refractory: A heat insulation material, such as fire brick or plastic fire clay, used for such
purposes as lining combustion chambers.
Fig 3.3 Fire tube boiler

23. 23
3.4 BOILER MOUNTINGS AND ACCESSORIES
3.4.1 Boiler mountings
Mountings are the machine components that are mounted over the body of the boiler itself
for the safety of the boiler and for complete control of the process of steam generation.
Various boiler mountings are as under:
1) Pressure gauge.
2) Fusible plug.
3) Steam stop valve
4) Feed check valve
5) Blow off cock
6) Man and mud holes.
1. Pressure gauge
Function: To record the steam pressure at which the steam is generated in the boiler.A
bourden pressure gauge in its simplest form consists of elliptical elastic tube ABC bent
into an arc of a circle as shown in figure. This bent up tube is called as BOURDEN’S
tube. One end of tube gauge is fixed and connected to then steam space in the boiler. The
other end is connected to a sector through a link.
2. Fusible plug:
Function: To extinguish fire in the event of water level in the boiler shell falling below a
certain specified limit. It protects fire tubes from burning when the level of the water in
the water shell falls abnormally low and the fire tube or crown plate which is normally
submerged in the water, gets exposed to steam space which may not be able to keep it
cool. It is installed below boiler's water level. When the water level in the shell falls
below the top of the plug, the steam cannot keep it cool and the fusible metal melts due to
over heating. Thus the copper plug drops down and is held within the gunmetal body by
the ribs. Thus the steam space gets communicated to the firebox and extinguishes the fire.
Thus damage to fire box which could burn up is avoided. By removing the gun metal plug
and copper plug the fusible plug can be put in position again by interposing the fusible
metal usually lead or a metal alloy.

24. 24
3. Steam stop valve
A valve is a device that regulates the flow of a fluid ( gases, fluidized solids, slurries, or
liquids) by opening, closing, or partially obstructing various passageways Function: to
shut off or regulate the flow of steam from the boiler to the steam pipe or steam from the
steam pipe to the engine. When the hand wheel is turned, the spindle which is screwed
through the nut is raised or lowered depending upon the sense of rotation of wheel. The
passage for flow of steam is set on opening of the valve.
4.Feed check valve
i) To allow the feed water to pass into the boiler.
ii) To prevent the back flow of water from the boiler in the event of the failure of the
feed pump.
5.Blow off cock
Function: To drain out the water from the boiler for internal cleaning, inspection or
other purposes.
6.Man and mud holes
To allow men to enter inside the boiler for inspection and repair.
3.4.2 Boiler accessories
Accesorries are those components which are installed either inside or outside the boiler to
increase the efficiency of the plant and to help in the proper working of the plant.
Various boiler accessories are:
1) Air Preheater
2) Economizer
3) Superheater
1.Air preheater
Waste heat recovery device in which the air to on its way to the furnace is heated utilizing
the heat of exhaust gases

25. 25
2.Economiser:
Function:To recover some of the heat being carried over by exhaust gases (This heat is
used to raise the temperature of feed water supplied to the boiler.
3. Superheater :
To superheat the steam generated by boiler Super heaters are heat exchangers in which
heat is transferred to the saturated
steam to increase its temperature.
3.5 BOILER INFORMATION[8]
Boiler stacks and chimneys - Reprinted Courtesy of the National Board of Boiler and
Pressure Vessel Inspectors. Any boiler using a combustible fuel source requires a stack or
chimney. The stack or chimney aids combustion in natural draft boilers by helping to
ensure a steady supply of combustion air which mixes with the fuel. The primary purpose
of a stack or chimney, though, is to exhaust the products of combustion at some elevation
above the boiler which aids the environmental conditions in the immediate area around
the boiler. The height of the stack or chimney is determined by several factors including:
 height of the nearest building or roof line
 prevailing wind direction
 height of surrounding manmade structures or natural landforms
 location of air intake vents
 type of boiler draft (natural or fan assisted)
 type of fuel
 local and/or national requirements
3.6 CAUSES OF BOILER ACCIDENTS
Boiler systems are designed for safety and efficiency. The boiler operator is the key to
safe boiler operations. Having knowledge about boiler systems and maintenance can
ensure years of safe, reliable service. History has shown that without proper operation and
maintenance, boiler conditions and safety deteriorate causing potential hazards due to
neglect and misunderstanding. Routine maintenance is well within the ability of most
boiler operators. Boiler tune up and repairs, however, are best left to trained

26. 26
professionals. Understanding when to turn to qualified professionals for assistance is one
of the operator’s responsibilities and can save time and money. Some of the areas where
trained professionals are needed are:
 Leaking safety and or safety relief valves
 Feed water to boiler
 Steam leaks (steam systems)
 High stack temperatures (excess of 350ºF)
 Insufficient heat for building
 Condensate dripping down stack or out the front of the boiler
 Constantly resetting of controllers and safety devices
Boiler accidents can occur when the boiler is allowed to operate without adequate water
in the boiler. Proper functioning low water cutoffs are essential to prevent these types of
accidents. Boiler damage can run from severe buckling and deforming of the boiler to
complete meltdown or potential boiler explosions.
Another type of boiler accident and the most lethal is excessive pressure. These accidents
occur when the boiler can no longer contain the excessive pressure allowed to build in the
boiler. Excessive pressure accidents, even in small boilers, have been known to
completely destroy a building.
Fuel related accidents usually occur when there is a failure to purge combustible gases
from the firebox before ignition is attempted. Leaking fuel valves can also be the cause of
these accidents. If the operator notices any gas odor, the boiler should be shut down and
the fuel supplier notified immediately.
“Never bypass safety devices with jumper wires to restart your boiler. Unintended
ignition of unburned combustion gases in the fire box is possible.”
3.7 BOILER INSPECTIONS
Much like your automobile, furnace, or air conditioner, a boiler requires an ongoing,
routine maintenance and inspection program. Well trained maintenance personnel, boiler
operators and boiler inspectors are important components to the safe operation of a boiler.
Routine boiler inspections are required by the Texas Boiler Law and Rules. The State and

27. 27
Authorized Inspection Agencies provide trained personnel throughout the state to perform
the required inspections to be in compliance with the Texas Boiler Law and Rules. A
boiler should be examined internally and externally to determine the operating condition
of the boiler and to ascertain the true condition of the boiler.
Boiler inspectors examine the structural integrity of the boiler along with the
associated safety devices attached to the boiler. These devices must remain in good
operating condition for the continued safe operation of the boiler.
The loss of water (low water), furnace explosion, over pressure and excessive temperature
are the principal causes for boiler accidents and are primarily the direct result of the
missing or inoperative controls and safety devices, lack of maintenance, untrained
operators, and complacency. These are some reasons why boiler inspections are so
important and what could result if boilers are left uninspected.
3.7.1 Option checklist
This section includes the most common options for improving a boiler’s energy efficiency.
Periodic tasks and checks outside of the boiler:
 All access doors and plate work should be maintained air tight with effective gaskets.
 Flue systems should have all joints sealed effectively and be insulated where
appropriate.
 Boiler shells and sections should be effectively insulated. Is existing insulation
adequate?
 If insulation was applied to boilers, pipes and hot water cylinders several years ago, it
is almost certainly too thin even if it appears in good condition. Remember, it was
installed when fuel costs were much lower. Increased thickness may well be justified.
 At the end of the heating season, boilers should be sealed thoroughly, internal
surfaces either ventilated naturally during the summer or very thoroughly sealed with
tray of desiccant inserted. (Only applicable to boilers that will stand idle between
heating seasons).

28. 28
3.8 CONCEPT OF EQUIVALENT EVAPORATION[4]
For comparing performance of various boilers, it is assumed to be operating under
standard pressure 1 atm ( 1.01325 bar at sea level) with feed water temperature 100 ˚C
and quality of steam obtained dry & saturated.
Under standard condition 1 kg of steam requires 2257 KJ/kg (hfg)
Let, m= amt of water evaporated in kg/hr or kg/kg of fuel burnt;
hfg = latent heat of vapourisation, KJ/kg;
x = actual dryness fraction;
hf = enthalpy of feed water at ‘t1’ ˚C =4.187 *t1 ;
hfg0 = latent heat of vaporization at 1.013 bar = 2257 KJ/kg ;
me = mass of equivalent vapourization from and at 100 ˚C ;
h = enthalpy of steam at outlet of the boiler;
= hf + (x*hfg) ; if wet
= hsup ; if superheated
= hg ; if dry & saturated
Heat required to produce 1 kg of steam = h – hf1 ;
Heat absorbed under standard condition = heat absorbed under actual condition ;
me * 2257 = m * (h – hf1);
me =
𝑚∗( ℎ−ℎ𝑓1)
2257
;
or me = m * fe; where fe = generation factor;
3.9 BOILER EFFICIENCY[4]
Thermal efficiency of a boiler is defined as “the percentage of (heat) energy input that is
effectively useful in the generated steam.” There are two methods of assessing boiler
efficiency:

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 The Direct Method: the energy gain of the working fluid (water and steam) is
compared with the energy content of the boiler fuel
 The Indirect Method: the efficiency is the difference between the losses and the
energy input
The various energy efficiency opportunities in a boiler system can be related to:
1. Stack temperature control
2. Feed water preheating using economizers
3. Combustion air pre-heating
4. Incomplete combustion minimization
5. Excess air control
6. Radiation and convection heat loss avoidance
7. Automatic blow down control
8. Reduction of scaling and soot losses
9. Reduction of boiler steam pressure
10. Variable speed control for fans, blowers and pumps
11. Controlling boiler loading
12. Proper boiler scheduling
13. Boiler replacement
Direct method of determining boiler efficiency
This is also known as ‘input-output method’ due to the fact that it needs only the useful
output (steam) and the heat input (i.e. fuel) for evaluating the efficiency. This efficiency can
be evaluated using the formula:
Boiler Efficiency, (η) =
Heat Output
Heat Input
* 100
Boiler Efficiency, (η) =
m x (hg – hf)
mf x GCV
* 100
Parameters to be monitored for the calculation of boiler efficiency by direct method are:
 Quantity of steam generated per hour (m) in kg/hr.
 Quantity of fuel used per hour (mf) in kg/hr.
 The working pressure (in kg/cm2(g)) and superheat temperature (Celcius), if any
 The temperature of feed water (Celcius)
 Type of fuel and gross calorific value of the fuel (GCV) in kcal/kg of fuel
And where

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hg – Enthalpy of saturated steam in kcal/kg of steam
hf – Enthalpy of feed water in kcal/kg of water
Advantages of direct method
� Plant workers can evaluate quickly the efficiency of boilers
� Requires few parameters for computation
Needs few instruments for monitoring
� Easy to compare evaporation ratios with benchmark figures
Disadvantages of direct method
� Does not give clues to the operator as to why efficiency of the system is lower
� Does not calculate various losses accountable for various efficiency levels
3.10 BOILER DO’S AND DON’TS
Do’s Don’ts
1. Soot blowing regularly
2. Clean blow down gauge glass once a shift
3. Check safety valves once a week
4. Blow down in each shift, to requirement
5. Keep all furnace doors closed
6. Control furnace draughts
7. Clear, discharge ash hoppers every shift
8. Watch chimney smoke and control fires
9. Check auto controls on fuel by stopping
feed water for short periods occasionally
10. Attend to leakages periodically
11. Check all valves, dampers etc. for correct
operation once a week
12. Lubricate all mechanisms for smooth
functioning
13. Keep switchboards neat and clean and
indication systems in working order
14. Keep area clean, dust free
15. Keep fire fighting arrangements at
readiness always. Rehearsals to be carried
1. Don’t light up torches immediately after
a fire-out (purge)
2. Don’t blow down unnecessarily
3. Don’t keep furnace doors open
unnecessarily
4. Don’t blow safety valves frequently
(control Operation)
5. Don’t over flow ash hoppers
6. Don’t increase firing rate beyond that
permitted
7. Don’t feed raw water
8. Don’t operate boiler blind fold
9. Don’t overload boiler as a practice
10. Don’t keep water level too high or too
low
11. Don’t operate soot blowers at high loads
12. Don’t trip the ID fan while in operation
13. Don’t look at the fire in furnace directly,
use tinted safety glasses
14. Avoid thick fuel bed

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out once a month.
16. All log sheets must be truly filled
17. Trip FD fan if ID fan trips
18. CO2 or O2 recorder must be
checked/calibrated once in three months
19. Traps should be checked and attended to
periodically
20. Quality of steam, water, should be
checked once a day, or once a shift as
applicable
21. Quality of fuel should be checked once a
week
22. Keep sub heater drain open during start
up
23. Keep air cocks open during start and
close
15. Don’t leave boiler to untrained
operators/technicians
16. Don’t overlook unusual observation
(sound change, change in performance,
control difficulties), investigate
17. Don’t skip annual maintenance
18. Don’t prime boilers
19. Don’t allow steam formation in
economizer (watch temps.)
20. Don’t expose grate (spread evenly)
21. Don’t operate boiler with water tube
leaking
3.11 CALCULATIONS ON BOILERS
Available boiler used in the plant of HIL company is:
 Three Pass Fully Wet Back Type.
 Designed with proper grate area and furnace volume for efficient burning of solid fuels
(Applicable for Solid Fuels)
 Good Combustion Efficiency as greater furnace diameters and furnace volumes are
provided.
 Higher efficiencies as designed properly with required heating surface areas.
 Available for liquid fuels like LDO/HSD/FO/LSHS, gaseous fuels like Natural
Gas/LPG/Biogas and Solid Fuels like Bagasse, Husk, Wood, Coal and other agro-wastes.
 Good Steam Purity up to 98% dry saturated as large disengaging surface and free board
distance in boiler.
 Steam Quality as 98% dry saturated.
 Consistent and trouble free performance under ‘Normal Operating Conditions’.
Working Pressures of Boiler available at 7 kg/sq.cm/10.54 kg/sq.cm/15 kg/sq.cm and 17.5
kg/sq.cm for complete range of boilers for different fuels.

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Figure 3.11.1 A typical 3 Pass, Oil fired packaged boiler
Technical Specification:
1) Steam generation capacity 14000 Kg/hr
2) Maximum operating pressure 12 Kg/cm2
3) Hydraulic test Pressure 18 Kg/cm2
4) Thermal efficiency based on fuel 87 +/- 2% on NCV of fuel
5) Steam quality (Dryness) 98% dry saturated: wet
steam
6) Type of grate Fixed Grate
7) Boiler design & construction IBR 1950 with latest
ammendments
8) Type of boiler Smoke tube wet back
10) No. Of furnace two
11) Heating surface area 401 m2
12) Flow rate of water 17.5 m3/hr

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Fig 3.11.2 Oil-fired boiler
GIVEN:
 Density of F/O : 0.97 kg/ltr.
 Calorific Value: 10,114 KJ/kg
 Equivalent evaporation F/A 100˚∆C: 14,000 kg/hr
 Dryness Fraction of Steam : 0.98
 Pressure of Steam inside the boiler: 12 kg/cm2
 Inlet water temperature, t1 = 60 ˚C
 Boiler efficiency : 87%
CALCULATIONS:
Pressure of steam:
1 kg/cm2 = 9.8066 N/cm2;
= 9.8066 * 10,000 N/m2;
= 0.98066 bar;
Therefore, 12kg/cm2 = 0.98066 * 12;
= 11.77 bar;
Condition of steam at 11.77 bar: (from steam table, using interpolation)
Saturated Temperature, Ts = 187.07 ˚C;

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Enthalpy of water, hf = 794.421 KJ/kg;
Latent heat of evaporation, hfg =1987.566 KJ/kg;
Specific Enthalpy of 0.98 dry steam, h = hf + ( x * hfg) = 794.421 + (0.98 * 1987.566)
h = 2742.236 KJ/kg ;
Specific enthalpy of water ( at 60 ˚C) , hf1 = cpw * ∆T
hf1 =4.187 * 60;
hf1 = 251.22 KJ/kg ;
1) Actual amount of water evaporated per hr (from section 3.8) :
m =
𝑚𝑒∗ 2257
( ℎ−ℎ𝑓1)
;
Therefore m =
14,000∗2257
(2742.236−251.22)
;
m = 12, 684.78 kg/hr ;
2) Amount of fuel used per day (from section 3.9)
We know, Boiler Efficiency, (η) =
m x (hg – hf)
mf x GCV
* 100 ;
& also, me * 2257 = m * (h – hf1);
Therefore, Boiler Efficiency, (η) =
me ∗ 2257
mf x GCV
* 100 ;
Boiler Efficiency, (η) =
14,000 ∗ 2257
mf x 10,114
* 100 = 87;
mf =
14,000∗2257∗100
10,114 ∗ 87
;
therefore, mf = 367.551 kg/hr ;
mf = 367.551 * 24 kg/day;
mf = 8821.226256 kg/day;

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we know, density =
𝑚𝑎𝑠𝑠 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒
𝑣𝑜𝑙𝑢𝑚𝑒 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒
;
therefore, Volume flow rate =
𝑚𝑎𝑠𝑠 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 (
𝑘𝑔
𝑑𝑎𝑦
)
𝑑𝑒𝑛𝑠𝑖𝑡𝑦 (𝑘𝑔/𝑙𝑡𝑟)
;
Volume flow rate =
𝟖𝟖𝟐𝟏.𝟐𝟐𝟔𝟐𝟓
0.97
ltr/hr ;
Volume flow rate = 9,094 ltr/day;
Therefore fuel requirement per day is estimated to be around 9 Kl/day
3) Chimney Height for boiler flue gas disposal
Ht. of chimney in meters = H =14 * Q1/3 ;
Where Q = amount of SO2 geenrated in kg/hr;
Boiler capacity =14 T/hr;
Fuel consumption = 3675.51 kg/hr;
Sulphur content as per IS1593 = 3.5 % max;
Amount of SO2 generated =
367.551 ∗ 3.5 ∗2
100
= 25.728 kg/hr ;
Ht. of chimney, H = 14 * 25.7281/3 = 14 * 2.920 ;
Chimney height, H = 40.885 m

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BIBLIOGRAPHY
[1] Stoecker and Jones, Refrigeration and Air Conditioning, Tata-McGraw Hill Publishers
[2] Adamczyk, J. J. (1999), "Aerodynamic Analysis of Multistage Turbomachinery Flows in Support of
Aerodynamic Design", ASME Paper 99-GT-80
[3] http://www.indiastudychannel.com/experts/23138-definition-Boiler.aspx
[4] B.L. Singhal(2009- 10) - ”Applied Thermodynamics”
[5] http://www.crazyengineers.com/community/threads/classification-of-boilers.39561/
[6] http://www.lowesforpros.com/maintaining-your-boiler-three-essential-elements
[7] http://www.crazyengineers.com/community/threads/boiler-terms.39562/
[8] www.rakoh .com
[9] http://www.parkerboiler.com/pdf/bulletins/Water%20Treatment/1001B-C.PDF