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PREFACE It is an honour for me to present this report through the sincere efforts and training done by me at the Verka Milk Plant, Mohali in the months of June and July. The co-ordinator assigned to me helped me immensely through the various sections of the plant and hence forth I’m able to present my learning in the pages ahead. I would like to welcome valuable suggestions and criticism from teachers as well as from the student community for further enhancing my learning.
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Verka Milk Plant report

Apr 25, 2017

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Page 1: Verka Milk Plant report

PREFACE

It is an honour for me to present this report through the

sincere efforts and training done by me at the Verka Milk

Plant, Mohali in the months of June and July. The co-ordinator

assigned to me helped me immensely through the various

sections of the plant and hence forth I’m able to present my

learning in the pages ahead.

I would like to welcome valuable suggestions and criticism

from teachers as well as from the student community for

further enhancing my learning.

Page 2: Verka Milk Plant report

HISTORY AND INTRODUCTION

OF ORGANIZATION

The Plant was established in 1980 by The Punjab Dairy

Development Corporation. The Punjab Dairy Development

Corp. and Milked are the two Government dairy organizations

which are running pay rolled to each other. In 1982 both these

organizations submerged into one which is now named as

MILKFED. In the beginning the capacity of the plant was

1,00,000 liters per day and the number of workers was only

700. The products manufactured initially were liquid milk,

ghee and cheese. Paneer production started in 1990 and curd

production started in 1997. The Plant has introduced ISO-

9002 quality Management System to ensure highest quality

products with built in safety to the consumers.

Milk Plant, Mohali is located at District Ropar in Punjab. It is

located on National Highway No. 21, joining Chandigarh with

Ropar, Jalandhar and Amritsar. It is situated in Phase-VI

Industrial area, Mohali at a distance of about 8km.from

Chandigarh. There is a great advantage as it is directly

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connected to National Highway which is facilitating all

transportation and allied facilities.

The main objectives for its establishment were:

1. To create an organized factor to develop and command a

major share of urban milk market of Patiala.

2. To provide year around renumeration price to the small

rural Milk producers organized into co-operative.

3. To provide quality milk and milk products to the customers.

4. To carry out activities conductive to the economic

development to agriculturist by organizing effective

production, process and marketing of commodities.

The milk plant has installed capacity of processing 1,00,000

litre of milk per day and it is managed by the qualified

professionals in the dairy field. The production facility is

backed by quality assurance, marketing training, financial

management, data processing and other required services,

providing a vibrant work environment to its personnel in

pursuit of excellence.

The milk plant is committed to supply quality and safe milk

and milk products to its esteem customer at the right time.

The milk plant is ISO 9001:2000 certified and also has a

Indian Standard of Hazard Analysis and Critical Points

certificate (HAACP)/IS: 15000-1998 to ensure highest quality

products with built in safety to customers.

Page 4: Verka Milk Plant report

PRODUCTS

It produces Standardized and Pasteurized Milk, Double Toned

Milk, PANEER, GHEE, LASSI, KHEER, CURD, SWEETENED

FLAVOURED MILK , etc. All these products are marketed at

the plant under the name “the Punjab State Co-operation Milk

Producers Federation Ltd” under the brand name of ‘Verka

Milk Plant.

ORGANISATION NETWORK

For the smooth running of plant, various sections are

managed by the management. Each and every activity is

delegated to particular section. It is impossible for top

management to take decision on every problem, so various

risks are delegate to various sections. These sections are

interrelated to have frequent contacts with one other and it is

easy to share the ingormarition. These integrated tasks teams

handle their problems and make their supervision easy.

The following are the sections in the Verka Organisation:

1. Procurement Section

2. Production Section

3. Quality Control Section

4. Marketing Section

5. Accounts Section

6. Administrative Section

7. Engineering Section

8. Purchase Section

9. Store Section

10. Security Section

Page 5: Verka Milk Plant report

I had the opportunity to explore and learn in the engineering

section under the able guidance of our coordinator and learn

about machines and latest processes utilised for milk

treatment. The engineering section comprised of the following

segments

BOILER SECTION

REFRIGERATION SECTION

HTST TREATMENT SECTION

It is my immense pleasure to present the report on all the

three sections of ENGINEERING SECTION based on the

observations and learning opportunity i had during my

training.

Page 6: Verka Milk Plant report

BASIC LAYOUT OF ENGINEERING

SECTION

In the following report all the 3 sections are described in the

following defined pattern in very descriptive way.

ENGINEERING SECTION

REFREGERATION SCETION

BOILER SECTION

HTST SECTION

Page 7: Verka Milk Plant report

REFREGERATION SECTION

Refrigeration is a process in which work is done to move

heat from a low temperature to a high temperature and

typically also from one location to another. The work of heat

transport is traditionally driven by mechanical work, but can

also be driven by heat, magnetism, electricity, laser, or other

means. Refrigeration has many applications, including, but

not limited to: household refrigerators,

industrial freezers, cryogenics, and air conditioning. Heat

pumps may use the heat output of the refrigeration process,

and also may be designed to be reversible, but are otherwise

similar to refrigeration units.

The refrigeration system requires a efficient material to

transport the heat which is known as refrigerant.

A refrigerant is a substance used in a heat cycle usually

including, for enhanced efficiency, a reversible phase

transition from a liquid to a gas. It changes from vapour liquid

to vapour during the process of absorbing heat and

condenses to liquid from vapour while liberating heat in most

of the refrigerating system. Traditionally, fluorocarbons,

especially chlorofluorocarbons, were used

as refrigerants, but they are being phased out because of

their ozone depletion effects. Other common refrigerants used

in various applications are ammonia, sulphur dioxide, and

non-halogenated hydrocarbons such as propane. Many

refrigerants are important ozone depleting and global

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warming inducing compounds that are the focus of worldwide

regulatory scrutiny.

TYPES OF REFRIGERANT

1. Primary Refrigerant

These refrigerants directly take part in the refrigerating

system and actually produce the low temperature. These are

ammonia, CO2, Sulphur Dioxide, Freon etc.

2. Secondary Refrigerant

These are firstly cooled by the primary refrigerant and

then they are further circulated for economical application in

the place to be cooled. They cools the substance by

absorbing their sensible heat. These include water, ice and

brine solution.

Refrigerants may be divided into three classes according to

their manner of absorption or extraction of heat from the

substances to be refrigerated:

Class 1:

This class includes refrigerants that cool by phase change (typically boiling), using the refrigerant's latent heat.

Class 2:

These refrigerants cool by temperature change or 'sensible heat', the quantity of heat being the specific heat capacity x

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the temperature change. They are air, calcium chloride brine, sodium chloride brine, alcohol, and similar nonfreezing solutions. The purpose of Class 2 refrigerants is to receive a reduction of temperature from Class 1 refrigerants and convey this lower temperature to the area to be air-conditioned.

Class 3:

This group consists of solutions that contain absorbed vapors of liquefiable agents or refrigerating media. These solutions function by nature of their ability to carry liquefiable vapors, which produce a cooling effect by the absorption of their heat of solution.

REFRIGERANT CHARACTERISTICS

Odor

Most refrigerants contain no odor in low concentrations. While having no odor at low levels, some concentrations of refrigerants smell distinctly chemical and refrigerant leakage is often identified by its chemical smell. In concentrations above 20 percent by volume of air, the odor resembles carbon tetrachloride, which smells sweet and is similar to the smell of cleaners used for dry cleaning.

Color and Stability

All pure refrigerants are colorless in both gaseous and liquid forms. Color may be added for identification purposes or may appear when mixed with other chemical compounds. Many refrigerant compounds are considered stable because of their ability to not decompose while going through the physical change of a gas to a liquid.

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Boiling Point

The boiling point of refrigerants depends on the atmospheric pressure. Many refrigerants have a boiling point between -45 and -33 degrees Celsius, with the exceptions of R12 and R11 that have very low boiling points of -29 and 9 degrees Celsius, respectively. At normal temperatures under average pressure, most refrigerants

remain in liquid form and must reach their boiling point to become a vapor.

Dangers and Benefits

Refrigerants with low boiling points may damage the eyes in their liquid states and protective eyewear must be worn at all times. If the liquid refrigerant comes into contact with the eyes, the tissues freeze. Most refrigerants don’t contaminate foods and are nonpoisonous in both gas and liquid forms, with the exception of ammonia, which is highly toxic. When mixed with air, vapor forms of refrigerants cause no harm to the eyes, nose, throat or lungs if inhaled. Excessive concentrations of refrigerant vapor causes unconsciousness and possible death because of a lack of oxygen to the brain. It has solvent properties that reduce and remove particles of dirt and oil within the cooling system. Most liquid and vapor forms of refrigerants will not corrode metals in cooling systems. Some, such as ammonia and R290, are highly explosive or flammable.

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AMMONIA REFRIGERATION SYSTEM

The milk plant requires a very efficient refrigeration system so

as to maintain the quality of their products and store them at

low temperatures. For this purpose the refrigeration system

employed in the milk plant is AMMONIA GAS

REFRIGERATION system in which ammonia (NH3) is used as

the refrigerant.

The basic components of refrigeration system are:

Compressor

Condenser

Expansion device

Evaporator

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The line numbers denote:

1. Hot gas (high pressure, high temperature)

2. Liquid (high pressure, warm temperature)

3. Liquid + vapor (low pressure, cold temperature)

4. Vapor (low pressure, cold temperature + ~10 ºF superheat)

Starting at the discharge connection of the compressor, line 1 conveys a high pressure superheated hot ammonia gas where it enters a heat exchanger i.e. the cooling tower where ammonia gas is cooled using water (the condenser). After entering, the gas is first desuperheated. Upon reaching its saturation temperature, the vapour then begins to condense, changing from a vapour state back into a liquid state. If additional heat is removed from this liquid stream, the process is known as “subcooling”.

Line 2 conveys the high pressure ammonia liquid stream from the condenser into an expansion device. There are many different types of expansion devices; in the following short list.

1. Capillary tubes (fixed)

2. Orifices (fixed, short orifice, Accurator)

3. Electronic expansion valves (modulating, senses refrigerant temperature rise across evaporator)

4. Thermal expansion valves (modulating, senses refrigerant superheat generated within evaporator)

5. Hand expansion valves (fixed but manually readjustable)

6. High-side floats (modulating, senses liquid level)

7. Liquid control valves (usually positioned by a remote high side float)

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Expansion devices numbered 1 through 4 are commonly applied in halocarbon refrigeration systems. Devices numbered 4 through 7 are used as throttling devices in industrial refrigeration systems and practices. In this milk plant HAND EXPANSION VALVE is used as expansion valve.

After leaving the expansion device, the refrigerant has now become a mixture of low pressure cold ammonia liquid and ammonia vapour as it travels down line 3. This mixture then enters an evaporator where the remaining liquid is boiled away while transferring heat energy across the evaporator tubing of cold stores or cooling water. If the expansion device measures ammonia superheat (or a temperature rise) occurring within the evaporator, the gaseous ammonia is then superheated slightly before it leaves the evaporator and enters line 4.

Line 4 (also known as suction) conveys the now slightly superheated low pressure vapour back into the compressor where its pressure and temperature are simultaneously raised to a level where heat can be rejected from the condenser into a heat sink (air).

COMPONENTS

i. Compressor motor

ii. Compressor

iii. Discharge line

iv. Oil separator

v. Check valve

vi. Condenser

vii. Receiver

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viii. Safety valve

ix. Liquid line

x. Expansion valve

xi. Chilled water tank

xii. Agitator fan

xiii. Evaporator (cooling coil)

xiv. Chilled water

xv. Suction line

RECIPROCATING COMPRESSOR

Reciprocating compressors utilize crankshaft driven pistons to

compress gases for use in various processes. Much like

internal combustion engines, an offset crankshaft causes

rotary motion of a piston rod which is converted to linear

motion via a crosshead. The crosshead can only move in a

linear motion so that the rotary motion of the crankshaft is

transformed into linear motion of the piston. As the piston

moves to and fro, it takes in low pressure gas and increases

its pressure. Unlike an internal combustion engine, the gas is

not ignited. It is allowed to leave the compressor cylinder at a

higher level of pressure than when it went in

Main parts of reciprocating compressor:

1. HEAD PLATE

It consists of two compartments made of cast iron with a

very smooth surface. The refrigerant is sucked and

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discharged through these compartments. Both are

connected with inlet & outlet of compressor.

2. VALVE PLATE AND VALVES

A valve plate has suction and discharge valve seats with a

very fine and smooth surface. The function of valve is to

direct the flow of refrigerant through the compressor and

maintain difference of pressure between the high side and

low side of the compressor. A valve which sucks the

refrigerant is called suction valve and the other one which

discharge the refrigerant is called discharge valve.

3. CYLINDER

Gas is compressed in cylinder of the compressor be

reciprocating motion of the piston.

4. PISTON AND PISTON RINGS

Piston are made of best grade cast iron and mechanically

polished. The Se has drilled holes to fit the piston pin. The

function of the piston is to compress the refrigerant in an

enclosed cylinder. Generally two or more piston rings are

used on a piston. They are made of cast iron. The function

of a piston ring is to maintain the proper lubrication and a

good seal between the piston wall and a cylinder wall to

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prevent the leakage of the compressed gas in the crank

case.

5. CONNECTING RODS and PISTON PIN

It forms the link between the piston and the shaft. To

provide piston pin lubrication mant connecting rods have an

oil holes for supplying the oil.

6. SHAFT

It is a moving part, which moves, in a rotary motion in the

main bush bearings of compressor. It is used to change

the rotary motion of fly wheel to reciprocating motion of the

piston, with the help of connecting rod. Only two types of

shafts are used in compressor:-

(a) Crankshaft (b) Eccentric Shaft

7. SHAFT SEAL

It is located where shaft leaves the compressor towards

the flywheel. It is the main part where leakage

can be occurred easily. There are two types of shaft seal:-

(a) Bellow type Seal (b) Rotary type Seal

Page 17: Verka Milk Plant report

8. FLY WHEEL

Fly wheel is generally made of cast iron. It is connected to

the one end of the shaft for driving the compressor. The “V”

belt is connected with it.

Page 18: Verka Milk Plant report

BOILER SECTION

A boiler is an enclosed vessel that provides a means for

combustion heat to be transferred into water until it becomes

heated water or steam. The hot water or steam under

pressure is then usable for transferring the heat to any

process. This steam thus generated is used in different

processes to transfer heat in manufacturing of different

products in milk plant.

Steam boiler can be categorized into 2 types:

1. Fire tube boiler: Fire tube or "fire in tube" boilers contain

long steel tubes through which the hot gasses from a

furnace pass and around which the water to be

converted to steam circulates

2. Water tube boiler: Water tube or "water in tube" boilers

in which the conditions are reversed with the water

passing through the tubes and the hot gasses passing

outside the tubes

Both types are described below in detail with diagrams.

Page 19: Verka Milk Plant report

FIRE TUBE BOILER

In a fire tube steam boiler, heat and gases of combustion pass through the tube surrounded by water. Fire tube boilers steam boilers maybe either high or low pressure boilers. The three types of fire tube steam boilers are horizontal return tubular boiler, scotch marine boiler, and vertical fire tube boiler. All fire tube boilers have the same basic operating principles. The heat produced by the gases of combustion pass through the tubes while the water surrounds the tubes. However, fire tube boilers have different designs like 2 pass, 3 pass, and 4 pass based on application and installation considerations. Fire tube boiler tubes are always measured by their outside diameter (O.D.). Fire tube boilers

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are usually designed for pressures up to a maximum of 250 psi and approximately 750 horsepower. HOW THEY WORK: When water is heated, it increases in volume and becomes lighter. This warmer water, now lighter, rises and the cooler water drops to take its place. The steam bubbles that eventually form break the surface of the water and enter the steam space. The addition of tubes inside the drum containing the water increases the heating surface. The heating surface is that part of the boiler with water on one side and the heat and gases of combustion on the other. By increasing the heating surface, more heat is taken from the gases of combustion. This results in a more rapid water circulation and faster formation of steam bubbles. When larger quantities of steam are released, the thermal efficiency of the boiler increases. Thermal efficiency is the ratio of the heat supplied from the fuel to the heat absorbed by the water. Modern fire tube boilers with improved design and heat transfer rates have achieved thermal efficiency rates as high as 80% to 85%. Placing an internal furnace within the boiler shell greatly increases the heating surface allowing for maximum absorption of heat thus reducing the time to create steam.

BOILER SAFETY:

Because of the large volume of water fire tube boiler contain, disastrous explosions may occur. Explosions may occur because of a sudden drop in pressure without a corresponding drop in temperature. Knowledge of basic principles of boiler operation can prevent serious accidents.

Page 21: Verka Milk Plant report

Water will boil and turn into steam when it reaches 212 degrees F at atmospheric pressure. The higher the steam pressure, the higher the boiling point of the water in the boiler. As steam pressure in the boiler increases, there is a corresponding increase in temperature. When a steam boiler is operating at 100 psi gauge pressure the temperature of the water and steam will be about 337 degrees F. If there is a sudden drop in pressure from 100 psi to 0 psi without a corresponding drop in temperature, the water at 337 degrees F flashes into steam. When water flashes into steam its volume increases tremendously. This can result in a disastrous explosion. It is imperative that maximum care is exercised in the operation and maintenance of the fire tube boiler. This includes annual boiler inspections of the waterside and fireside of the boiler. Controls such as the low water cut off, relief valves, and flame safeguards must all be in correct working order.

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WATER TUBE BOILER

A water tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which heats water in the steam-generating tubes. In smaller boilers, additional generating tubes are separate in the furnace,

while larger utility boilers rely on the water-filled tubes that make up the walls of the furnace to generate steam.

The heated water then rises into the steam drum. Here, saturated steam is drawn off the top of the drum. In some services, the steam will reenter the furnace through a superheater to become superheated. Superheated steam is defined as steam that is heated above the boiling point at a

Page 23: Verka Milk Plant report

given pressure. Superheated steam is a dry gas and therefore used to drive turbines, since water droplets can severely damage turbine blades.

Cool water at the bottom of the steam drum returns to the feedwater drum via large-bore 'downcomer tubes', where it pre-heats the feedwater supply. (In 'large utility boilers', the feedwater is supplied to the steam drum and the downcomers supply water to the bottom of the waterwalls). To increase economy of the boiler, exhaust gases are also used to pre-heat the air blown into the furnace and warm the feedwater supply. Such water tube boilers in thermal power station are also called steam generating units.

In the VERKA MILK PLANT MOHALI the type of boiler used is FIRE TUBE BOILER which are, two 3 pass horizontal fire tube boilers which work with the capacity of 3 ton and 2 ton respectively.

Page 24: Verka Milk Plant report

Boiler Fittings and Accessories

BED

The silica sand is used for the proper combustion of husk.

Silica sand is used because it can bear high temperature. The

bed is nozzle type; its shape is square type. The air for

combustion of fuel comes from the air pre-heater. Then this

preheated air goes inside the bed at very high speed through

nozzles. When the air comes at high pressure the silica sand

jumps due to high pressure of air and proper mixing of fuel

and air takes place. Thus firing of fuel easily takes place.

There are two beds in a boiler. Each bed has two gates one at

the front and the other at the rarer side. Temperature of bed is

normally 700c.

The ash due to the firing of husk is removed with the help of

rotary valve. The ash goes to the ash collector with the help of

ID fan. There are two rotary valves in a boiler operate by the

electric motor. The ash from the rotary valve goes to the ash

conveyor. In the ash conveyor a plastic belt moves on the

roller normally a small quantity of water is added to ash so as

to easily collect the ash.

ECONOMIZER

An economizer is a device used to heat feed water by utilizing

the heat in the exhaust flue gases before leaving through the

chimney. As name indicates the economizer improves the

economy of the steam boiler. It may be note that temperature

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of the feed water should not be very low; otherwise there is

danger of corrosion.

Advantage of economizer

There is about 15to 20% saving of fuel

It increases the steam rising capacity of the boiler because it shortens the time required to converts water into steam.

It prevents the formation of scale.

Since the feed water entering the boiler is hot, therefore starting due to unequal expansion is minimize

AIR PREHEATER

An air pre-heater is used to recover heat from exhaust flue

gases. It is installed between the economizer and chimney.

The air required for the purpose of combustion is drawn

through the air pre-heater where its temperature is raised. It is

then passed through the duct of the furnace. The air is passed

through the tubes of the heater

internally while the flue gases passed over the outer side of

the tubes.

Advantages of using air pre-heater:

The pre-heater gives higher furnace temperature which results in more heat transfer to the water and thus increases the evaporation capacity per kg of fuel.

There is an increase of about 2% in the boiler efficiency for each 35to 40c rise in temperature.

It results in better combustion with less soot, smoke and ash.

It enables a low grade fuel to be burnt with excess air.

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BOILER DRAUGHT

It is used to remove the energy content from the flue gases to

the water being evaporated.

Forced Draught Fan This is used for proper mixing of air and fuel. By proper

mixing the efficiency of boiler is increased. It is placed with

the air pre-heater. Hot air from the pre-heater is fed in the

furnace with the help of forced draught fan.

Induced Draught Fan It is used to produce vacuum. Due to vacuum the flue

gases are easily removed from the grate. It is placed the

chimney and ESP.

CHIMNEY

It is used to remove exhaust gases to the environment. In this

industry the height of chimney is 55m.

BOILER DRUM

The water goes in the boiler drum. In boiler drum there is 75%

water and 25% air. There are steel pipes welded in the drum.

The flue gases are passed through these pipes for heating the

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water. The level of water is checked with the help of water

level indicator.

FUEL FIRING

Heated air from the air preheated goes to the firs grate, where

firing of fuel takes place with the help of wood, coal and

kerosene oil.

STEAM HEADER

Saturated steam produced in the boiler comes to the steam

header from where some steam goes directly to the plant and

some to the super heater.

SUPERHEATER

Its function is to convert the saturated steam to superheated

steam. In internal type super heater, super heater is fitted in

side the furnace. Saturated steam is passed through tubes on

the super heater and due to high temperature the saturated

steam is converted into superheated steam.

SAFETY VALVE

Its function is to permit the steam in the boiler to escape to

atmosphere when pressure in the steam space exceeds a

certain specified limit. Thus the two safety valves prevent the

building up of excessive pressure in the boiler.

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WATER LEVEL INDICATOR

The function of water level indicator is to keep water level

constant. It is also known as water gauge. It is fitted at the

front of the boiler from where it is easily visible.

PRESSURE GUAGE

Its function is to record the pressure at which the seam is

being generated in the boiler. The gauge is mounted at the

front top of the boiler shell. The gauge has to be clearly visible

to the attendant so that operator can easily record the

pressure reading. Mostly bourdon pressure gauge is used.

BLOW OFF COCK

It serves to drain out the water from the boiler periodically so

as to:

Discharge mud, scale and other impurities which settle down at the bottom of the boiler.

To empty the boiler for internal cleaning and inspection.

To lower water level rapidly if level becomes too high. This unit is fitted at the lower portion f the boiler. It may be mounted directly to the boiler shell.

FEED CHECK VALVE

Its main function is:

To allow the feed water to pass into the boiler.

To prevent the backflow of water from the boiler in the event of the failure of the feed pump.

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This valve is installed between the feed pump and the

boiler shell.

MANHOLE

There are two man holes to allow men to enter inside the

boiler for inspection and repair. Manholes are in water drum

one on lower side and other on the upper side of the drum.

STEAM STOP VALVE

It is the largest valve on the boiler. It is usually fitted to the

highest part of the shell by means of a flange. The main

function of this valve is:

To control the flow of steam from the boiler to the main steam pipe.

To shut of the steam completely when required.

INDIAN BOILER REGULATIONS(1950)

HISTORY

In the year 1863, a very serious boiler explosion occurred in

Calcutta which caused the loss of several lives. As a result of

this explosion, the necessity of inspection of boilers was

widely recognised and a bill was introduced in the Bengal

Council to provide for the inspection of steam boilers. In the

year 1864, the Bengal Act VI of 1864 was passed which

provided for the inspection of steam boilers and prime movers

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in the town and suburbs of Calcutta. In the year 1863, a very

serious boiler explosion occurred in Calcutta which caused

the loss of several lives. As a result of this explosion, the

necessity of inspection of boilers was widely recognised and a

bill was introduced in the Bengal Council to provide for the

inspection of steam boilers. In the year 1864, the Bengal Act

VI of 1864 was passed which provided for the inspection of

steam boilers and prime movers in the town and suburbs of

Calcutta. This is the beginning of boiler legislation in India.

Following the Bengal Act of 1864, each of the other provinces

framed legislation. At that time there were seven different Acts

and seven different sets of rules and regulations. Those Acts

and rules & regulations were

inconsistent with one another. As the differences in the Acts

and rules and regulations among the various provinces in

India gave rise to many difficulties and hampered the

development of industries, the Central Government appointed

a committee called "The Boiler Law Committee" in 1920 to

examine and report on the general question of boiler

legislation in India.

The Boiler Laws Committee, 1920-21, the first to review the

boiler laws on a national scale reported in March, 1921. The

report criticised the differences in the Acts, rules and

regulations. The Committee recommended that regulations to

cover the standard conditions for material, design and

construction of boilers should be framed by Government of

India and make applicable to all the provinces. The

Committee prepared a draft Act on the lines of which, the

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basic All-India Act was passed in 1923. The Boiler Laws

Committee also prepared a uniform set of technical

regulations and a model set of administrative rules. A sharp

distinction was drawn between the regulations and the rules.

The regulations referred entirely to technical matters where as

the rules referred to questions concerning the administration

of the Act. Indian Boiler act, 1923 provides for the safety of life

and

property of persons from the danger of explosion of boilers.

The Government of India Act, 1935 assigned the subject

'Boilers' to the concurrent field. The provision for constituting

Central Boilers Board having the authority to make regulations

consistent with the Act was made in the Indian Boilers

(Amendment) Act, 1937. A Board called the Central Boilers

Board was accordingly constituted in the year 1937.

The Central Boilers Board in exercise of the powers conferred

under section 28 of the said Act, formulated regulations on

boilers. The current version of these regulations is known as

the Indian Boiler Regulations, 1950 with amendments up to

22nd February, 2005.

Some of the definitions given by the IBR are as follows:

Boiler means any closed vessel exceeding 22.75 litres (five

gallons) in capacity, which is used expressly for generating

steam under pressure and includes any mounting or other

fitting attached to such vessel, which is wholly or partly under

pressure when steam is shut off.

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Calculation Pressure, in relation to a boiler, means the design

pressure of any part adjusted to take into account the

pressure drops corresponding to the most severe

conditions of pressure drop and hydraulic head.

Design Pressure means :-

i) In relation to a natural or assisted circulation boiler, the

maximum allowable working pressure in the steam drum

of the boiler.

ii) In relation to a once through forced-circulation boiler, the

maximum allowable working pressure at the final

superheater steam outlet.

Economiser means any part of a feed-pipe that is wholly or

partly exposed to the action of flue gases for the purpose of

recovery of waste heat.

Feed-pipe means ;-

(i) any pipe or connected fitting wholly or partly under

pressure through which feed-water passes directly to a boiler.

(ii) every reference to a steam-pipe or steam-pipes shall be

deemed to include also a reference to feed-pipe or feed-pipes

respectively.

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Steam-pipe means any pipe through which steam passes

from a boiler to a prime-mover or other user or both if :-

i) the pressure at which steam passes through such pipe

exceeds 3.5 Kilograms per square centimetre above

atmospheric pressure or

ii) such pipe exceeds 254 millimetres in internal diameter;

and includes in either case any connected fitting of a

steam-pipe.

Page 34: Verka Milk Plant report

HTST PASTEURIZATION SECTION

PASTEURIZATION

Pasteurization is a process of heating a food, which is

usually a liquid, to a specific temperature for a predefined

length of time and then immediately cooling it after it is

removed from the heat. This process slows spoilage due

to microbial growth in the food.

Pasteurization typically uses temperatures below boiling point.

The two main types of pasteurization used today are: high-

temperature, short-time (HTST) and "extended shelf life"

(ESL) treatment. Ultra-high temperature (UHT or ultra-heat-

treated) is also used for milk treatment. In the HTST process,

milk is forced between metal plates or through pipes heated

on the outside by hot water, and is heated to 73.8°C (165°F)

for 15–20 seconds. UHT processing holds the milk at a

temperature of 135°C (275°F) for a minimum of one second.

In VERKA MILK PLANT MOHALI, HTST method is used for

pasteurization which was designed to achieve a five-log

reduction, killing 99.999% of the number of viable micro-

organisms in milk. This is considered adequate for destroying

almost all yeasts, moles, and common spoilage bacteria and

also to ensure adequate destruction of common pathogenic,

heat-resistant organisms.

Page 35: Verka Milk Plant report

A pasteurization system normally contains the following

components:

• Balance tank with a float valve assembly: The balance, or

constant level tank provides a constant supply of milk. It is

equipped with a float valve assembly which controls the liquid

level nearly constant ensuring uniform head pressure on the

product leaving the tank. The overflow level must always be

below the level of lowest milk passage in regenerator. It,

Page 36: Verka Milk Plant report

therefore, helps to maintain a higher pressure on the

pasteurized side of the heat exchanger. The balance tank

also prevents air from entering the pasteurizer by placing the

top of the outlet pipe lower than the lowest point in the tank

and creating downward slopes of at least 2%. The balance

tank provides a means for recirculation of diverted or

pasteurized milk.

• Regenerator: A regenerative heat exchanger, or more

commonly a regenerator, is a type of heat exchanger where

the flow through the heat exchanger is cyclical and

periodically changes direction. a regenerator mixes the two

fluid flows while a counter current exchanger maintains them

separated. The temperature profile remains at a nearly

constant temperature, and this includes the fluid entering and

exiting each end.

Heating and cooling energy can be saved by using a

regenerator which utilizes the heat content of the pasteurized

milk to warm the incoming cold milk. Its efficiency may be

calculated as follows:

% regeneration = temp. increase due to regenerator/total

temp. Increase.

Page 37: Verka Milk Plant report

REGENERATOR

• High-pressure homogenizer: Milk homogenization is

accomplished by mixing massive amounts of harvested milk

to create a constant, then forcing the milk at high pressure

through small holes. Yet another method of homogenization

uses extruders, hammer mills, or colloid to mill (grind) solids.

Milk homogenization is an essential tool of the milk food

industry to prevent creating various levels of flavour and fat

concentration.

• A centrifugal pump with magnetic flow meter and

controller: A centrifugal pump or a booster pump maintains

the constant flow of milk in the regenerator with high pressure

so that the pressure required for the pasteurization is

maintained.

Page 38: Verka Milk Plant report

• Holding tube: A holding tube has a known-diameter pipe

designed to provide an established residence time for product

at the pasteurization temp., the critical time/temperature

relationship needed for pasteurization is achieved by the

residence time requirement in the holding tube. The length of

holding tube ensures the necessary residence time of

product.

• Recorder-controller: Recorder-controller is a digital device

which controls the temperature of the heat exchanger and the

regenerator at a constant point that is required for the

pasteurization.

• Flow diversion Valve: The FDV is controlled by a

temperature-sensing device located at the exit of the heating

section. If temperature is below the desired temperature, the

valve diverts flow to the entrance point. As soon as the

established temperature is reached, the flow diversion valve

changes and the product moves forward through the holding

tube. This control device ensures safety of product

• Centrifugal Separator: The separation of cream from milk

in the centrifugal separator is based on the fact that when

liquids of different specific gravities revolve around the same

centre at the same distance with the same angular velocity, a

greater centrifugal force is exerted on the heavier liquid than

on the lighter one. Milk can be regarded as two liquids of

different specific gravities, the serum and the fat.

• (+) some process automation and process integration.

Page 39: Verka Milk Plant report

CONCLUSION

• Came to know about various sections required for

running of an industry.

• Boiler and its various equipments such as

• Inlet of fuel and its pre-treatment.

• Treatment of water before feeding.

• Various safety measures taken with the

help of various valves installed.

• Insulation care to increase the effectiveness

and for proper working.

• How the different components work together to make

the industry and precisely how the different things

are recycled.

• How HTST milk is processed and its various

components and methodology.

• Most importantly how several constraints such as

capital and space utilization are used.

Page 40: Verka Milk Plant report

REFRENCES

1. www.wikipedia.com

2. www.google.com

3. A book named: Description of Modern HTST Plants

4. Thermax Boilers manual, Sustainable soiutions

Energy and Environment, PUNE

Page 41: Verka Milk Plant report

ACKNOWLEDGEMENT

It gives me immense pleasure & happiness to submit the

training report for training undertaken by me at VERKA

MILK PLANT, MOHALI.

Before I embark with the presentation of this training

report, I would like to acknowledge all contributions by

respected teachers and trainers who guided me

throughout my training.

I would like to EXPRESS MY HEART FILLED

GRATITUDE to our respected head of department Dr.

Rajeev Mehta for giving me the opportunity to undertake

this training programme.

I would like to thank our respected asst. Professor Mr.

Rakesh Kumar Gupta for his guidance and immense

support given by him to complete my training.

I would also like to express my deep sense of gratitude to

the general manager, verka milk plant Mohali Mr. T.P.S

Walia for extending his full support and help in completion

of my training.

They have been a great source of inspiration throughout

my training.

Page 42: Verka Milk Plant report

DECLARATION

I Harsh i t j ohar hereby dec la re tha t t he work p resen ted here in i s genuine work done originally by me and has not been published or submitted elsewhere for the requirement of a degree programme. Any literature, data or works done by others and cited within this project r e p o r t h a s

b e e n g i v e n d u e a c k n o w l e d g e m e n t .

Harshit Johar

Roll no.-101001026

B.E. THIRD YEAR