hmil - project report

HMIL – Project Report

A

Project Report On

Improving Inlet Conditions

Of

Centrifugal Air Compressor

Project Report

Improving Inlet Conditions


At Hyundai Motors Limited India,SriPerumbu

Sugan Durai Murugan V,

Suram Srikanth,

Department of Mechanical Engineering,

IIT Madras, Chennai


At Hyundai Motors Limited India, SriPerumbudur.

July – 2011.

Submitted by,

Sugan Durai Murugan V, ME09B056

Suram Srikanth, ME09B057

Department of Mechanical Engineering,

IIT Madras, Chennai – 36.


BONAFIDE CERTIFICATE

This is to certify that the project trainees V.Sugan Durai Murugan and

Suram Srikanth of INDIAN INSTITUTE OF TECHNOLOGY – Madras have

successfully completed their project on "Improving Inlet Conditions for

Centrifugal Compressors" in the Utilities & Services Department, Hyundai

Motors India Limited in July 2011.

Signature, Signature, Signature,

Mr. S. Balan Mr. S. Thirumalai Nambi Mr. C.S. Lakshmi Narayan

Project guide, Manager Manager, Deputy General Manager,

Utilities & Services, Utilities & Services, Utilities and Services,

HMIL . HMIL. HMIL.

*This document is property of HMIL, and is illegal to reproduce.


ACKNOWLEDGEMENT

We deeply thank Hyundai Motors Limited India and Utilities and

Services Department for providing an opportunity to do this project. We

would like to deeply acknowledge the support and guidance of Mr.S.BALAN –

Manager, U&S Department, without whom the project would not been this

successful.

We also would like to thank heart fully Mr.THIRUMALAI NAMBI -

Manager, U&S Department and Mr.C.S.LAKSHMI NARAYAN – General

Manager- U&S Department.

Our sincere thanks to all the staff members of U&S Department for

support and help in the completion of project. We also would like to thank all

the Technicians in Compressors, Water Treatment plant and Propane yard,

who helped us in understanding of the processes involved in the plant.


ABSTRACT

Energy conservation is the most important task that all the industries

leaning for. Certain innovative methods which reduce energy consumption are

considered as energy conservation methods. That includes all the new

physically and chemically evolved processes, which pave their way for Energy

Conservation. All of the processes do not result in positive manner, because

each and every process does have their own problem of Investment,

Environmental impacts, and Life span. They may or may not uplift the profit

obtained in implementing them.

Efficiency is a more suitable term used in this context. In energy

competing society, getting the maximum efficiency for their machines is the

main motto of all the Companies. In case of Centrifugal air Compressor; the

term efficiency goes with different factors.

Giving cooler and lighter air to compressor is one of the ways to save

power consumption in Compressor Working and to improvise its efficiency.

Many machines do that job. But we need that kind of machines which can cope

up with compressor flow rate, withstanding the continuity of compressor, the

changes in pressure.

The basic principle behind the Cooled and dehumidified air is

refrigerating the air. Nowadays Refrigeration comes in handy with lot of

physical principles. This project elaborates about Centrifugal Compressor and

some of the principles used in energy efficient context.

This project report shows with theoretical assumptions and practical

ways to find the energy savings, their respective annual savings on those

Efficiency Optimizing principles to operate on HMIL’s Centrifugal Compressor.


TABLE OF CONTENTS

� HMIL and U&S Department.

� Report on Propane Yard.

� Report on Water treatment plant.

� Report on Boiler plant.

� Project on Centrifugal Compressor.

o About

o Parts

• Inlet

• Impeller

• Diffuser

• Coolers

o Working

o Performance and Control

o Centrifugal Compressor Instabilities.

• Surge

• Rotating Stall

o Efficiency

• Volumetric Efficiency

• Isentropic Efficiency

• Polytropic Efficiency

o Improving Inlet Conditions

• Pre-cooled air intake

• Decrease in Humidity

o Achieving Better Inlet Conditions

• Evaporative Coolers

• Chiller Coils

• Comparison

o Conclusion


HMIL

Hyundai Motor India Limitedis a wholly owned subsidiary of the

Hyundai Motor Company in India. It is the 2nd largest automobile

manufacturer in India.

LOCATION:

HMIL is situated in Sriperumbudur in the Kanchipuram district of Tamil

Nadu.Here HMIL has two manufacturing plants capable of producing 600,000

vehicles annually.

HYUNDAI LOGO(HISTORY AND DESIGN):

The Hyundai logo seen above is appears to be an oval shaped H

(symbolizing Hyundai). It is also supposed to be symbolic of the company's

desire to expand. The ovaloid shape indicates the company's global expansion

and the slanted, stylized 'H' is symbolic of two people (specifically the company

and customer) shaking hands.

HYUNDAI MOTOR COMPANY:

Hyundai Motors Company is a Korean automaker which along with Kia

comprises the Hyundai Kia Automotive Group, the world's fourth largest

automaker as of 2009. As of 2009, it is the world's fastest growing automaker.

In 2008, Hyundai (without Kia) ranked as the eighth largest automaker.

Headquartered in Seoul, South Korea, Hyundai operates the world's

largest integrated automobile manufacturing facility in Ulsan, which is capable

of producing 1.6 million units annually.

The Hyundai Motor Company (HMC) is a South Korean company

manufacturing automobiles. Their automobiles are available in many countries

around the globe. In 2003 it was South Korea's largest car maker and the

world's seventh largest car maker. Its slogan is "Drive your way". Hyundai

Motor Company is a division of Hyundai Motor Group which also manages Kia

Motors.

The company employs about 75,000 persons around the world. Hyundai

vehicles are sold in 193 countries through some 6,000 dealerships and

showrooms worldwide. In 2010, Hyundai sold over 1.7 million vehicles

worldwide.


HISTORY:

Chung Ju-Yung founded the Hyundai Engineering and Construction

Company in 1947. Hyundai Motor Company was later established in 1967. The

company's first model, the Cortina, was released in cooperation with Ford

Motor Company in 1968.

When Hyundai wanted to develop their own car, they hired

George Turnbull, the former Managing Director of Austin Morris at British

Leyland. He in turn hired five other top British car engineers. They were

Kenneth Barnett body design, engineers John Simpson and Edward Chapman,

John Crosthwaite ex-BRM as chassis engineer and Peter Slater as chief

development engineer.

In 1975, the Pony, the first Korean car, was released, with styling by

Giorgio Giugiaro of Ital Design and power train technology provided by Japan's

Mitsubishi Motors. Exports began in the following year to Ecuador and soon

thereafter to the Benelux countries. In 1991, the company succeeded in

developing its first proprietary gasoline engine, the four-cylinder Alpha, and

transmission, thus paving the way for technological independence.

In 1986, Hyundai began to sell cars in the United States, and the Excel

was nominated as "Best Product #10" by Fortune magazine, largely because of

its affordability. The company began to produce models with its own

technology in 1988, beginning with the midsize Sonata.

In May 6th

1996, Hyundai Motors India Limited was established with a

production plant in Irrungattukotai near Chennai, India.

In 1998, Hyundai began to overhaul its image in an attempt to establish

itself as a world-class brand. Chung Ju Yung transferred leadership of Hyundai

Motor to his son, Chung Mong Koo, in 1999.

Hyundai's parent company, Hyundai Motor Group, invested heavily in

the quality, design, manufacturing, and long-term research of its vehicles. It

added a 10-year or 100,000-mile (160,000 km) warranty to cars sold in the

United States and launched an aggressive marketing campaign.

In 2004, Hyundai was ranked second in "initial quality" in a survey/study

by J.D. Power and Associates. Hyundai is now one of the top 100 most valuable

brands worldwide. Since 2002, Hyundai has also been one of the worldwide

official sponsors of the FIFA World Cup.


HMIL Policy:

HMIL’S policy is always to be a stickler for quality. HMIL presently

markets 16 variants of passenger cars in six segments. The Santro in the B

segment, Getz in the B+ segment, the Sonata Embera in the E segment and the

Tucson in the SUV segment.

HMIL's first car, the Hyundai Santro was launched in 23 September 1998

and was a runaway success.

CARS MANUFACTURED BY HMIL:

HMIL presently markets 6 models of passenger cars across segments.

• The A2 segment includes the Santro, i10 and the i20.

• The A3 segment includes the Accent and the Verna.

• The A5 segment includes the Sonata Transform.

• The SUV segment includes the Santa Fe.

• Latest segment includes now the Fluidic Verna also.

HMIL’s fully integrated state-of-the-art manufacturing plant near

Chennai boasts of the most advanced production, quality and testing

capabilities in the country. To cater to rising demand, HMIL commissioned its

second plant in February 2008, which produces an additional 300,000 units per

annum, raising HMIL’s total production capacity to 600,000 units per annum.

In continuation with its commitment to providing Indian customers with

cutting-edge global technology, HMIL has set up a modern multi-million dollar

research and development facility in the cyber city of Hyderabad. It aims to

become a centre of excellence for automobile engineering and ensure quick

turnaround time to changing consumer needs.

As HMC’s global export hub for compact cars, HMIL is the first

automotive company in India to achieve the export of 10 lakh cars in just over

a decade. HMIL currently exports cars to more than 110 countries across EU,

Africa, Middle East, Latin America, Asia and Australia. It has been the number

one exporter of passenger car of the country for the sixth year in a row.

To support its growth and expansion plans, HMIL currently has a 307

strong dealer network and 627 strong service points across India, which will

see further expansion in 2010.


EXPORTS:

HMIL currently exports vehicles to more than 110 countries across Europe,

Africa, Middle East, Latin America and Asia. It has been the number one

exporter of passenger cars for the sixth year in a row in India.

ACHIEVEMENTS:

HMIL has been the number one exporter of passenger car of the country

for the sixth year in a row.

Here are the achievements of HMIL over their period of time till today.

2010 • Fastest exports of 10 lakh cars

2009 • Hyundai Motor India Ltd. receives the EEPC

‘National Award for Export Excellence for 2007-

08. Hyundai won the Gold Trophy in the ‘Large

Enterprise’ category.

• Hyundai Motor India honoured with ‘EXIM

Achieved Award’ for the year 2008 by Tamil

Chamber of Commerce

• Hyundai Motor India conferred the Top

Exporter of the Year for 2006-07in the category

of ‘Large Enterprises’ and received the Gold

Trophy at the Southern Region Annual Award

Presentation by the Engineering Export

Promotion Council (EEPC).

2008 • Hyundai Motor India awarded with the ‘Niryat

Shree’ Silver Trophy for the year 2005-06 by

the Federation of Indian Export Organizations

(FIEO).

• Hyundai exports its first batch of ‘i20’ to

European market. The first export consignment

comprised 2,820 units of ‘i20’.

• Fastest Export - Over One lakh units of i10

exported since its launch in Oct 31, 2007

• Fastest Export of 5 lakh units

2007 • Fastest Export of 4 lakh units

• Hyundai Motor India adjudged the Top


Exporter of the Year for 2005-06 in the

category of ‘Large Enterprises’ and received

the Gold Trophy by the Engineering Export

Promotion Council (EEPC)

• Hyundai Motor India ships out the first Getz

2006 • Hyundai Motor India rolls out the fastest

300,000th export car

2005 • No 1 Entry Midsize Car' by Accent Petrol.

• No 1 Entry Midsize Car' by Accent CRDi.

• Hyundai Getz became the 'Car of the Year' by

BS Motoring.

• Hyundai Motor India Limited became the

'Company of the Year' by BS Motoring.

• Hyundai Getz became the 'CNBC Autocar Car of

the Year.'

• Hyundai Elantra became the 'Best Value for

Money Car' by CNBC.

2003 • Hyundai Motor India adjudged as the 'Car

Maker of the year' at the ICICI Bank Overdrive

awards.

2002 • Hyundai Santro topped the 'JD Power Asia

Pacific Initial Quality Study (IQS)' that measures

the product quality for three consecutive years

(2000, 2001 & 2002).

• Hyundai Santro topped the 'JD Power Asia

Pacific Apeal' study that measures customer

satisfaction for three consecutive years (2000,

2001 & 2002).

• Hyundai Accent topped the 'JD Power Asia

Pacific IQS' for 2002 and the APEAL study for

2001 & 2002.


U & S DEPARTMENT

Utilities and Services Department is one of the main departments in HMIL.

It controls the Needs for the whole plant. It maintains

• Propane Yard

• Water and Waste Water Treatment Plant

• Boilers

• Air Compressors

• Electricity power

• Air Conditioners

• Air Washers

• Mist Collectors etc.

And with control over these, the U&S department provides plant

Propane gas as fuel, Supplying industrial and canteen water, Electricity, Steam,

Compressed air, treatment in waste water, air conditioning. In fact, U&S

Department is the fuel behind the working of plant. Because it takes control

over all the main energy sources for engine shop, body shop, Paint shop,

Aluminium foundry, even for Canteen. Therefore U&S Department is the

steering wheel for Plant Production.

This Project concentrates on some of the equipment in U & S

Department controlled plants, which are

• Propane Yard

• Water Treatment plant

• Boilers

• Centrifugal Compressor


PROPANE YARD

ABOUT PROPANE:

Propane is a gas derived

from natural gas and petroleum.

It is found mixed with natural gas

and petroleum deposits. Propane

is one of the many fossil fuels

included in the liquefied

petroleum gas (LPG) family.

Propane is a very clean burning fossil fuel, w

settings. It was approved as an alternative fuel under the Clean Air Act, as well

as the National Energy Policy Act

Propane undergoes

Alkanesi. In the presence of excess oxygen, propane burns to form water and

carbon dioxide.

C3H8 + 5 O2 → 3 CO

Propane + oxygen → carbon dioxide + water

When not enough oxygen is present for complete combustion,

incomplete combustion occur when propane burns and forms water,

monoxide, carbon dioxide

2 C3H8 + 7 O2 → 2 CO

Propane + Oxygen → Carbon dioxide +

Water

PROPANE IN HMIL:

HMIL Utilises propane fuel in gas form, in 24X7basis. The yard has two

bullets of Propane tank, Vaporiser, and Compressor units. Each Propane bullet

has a Capacity of 95 MT, storing propane in both liquid

average the plant utilizes around 23 MT of propane daily. The pressure level of

the propane is seen through the pressure gauge. And only upto 70 to 75

percentage of volume is filled with propane, because propane is easily

expandable with temperature increase. Also bullet tank is designed with huge

thickness to withstand any expansion or explosion.

PROPANE YARD

Propane is a gas derived

from natural gas and petroleum.

It is found mixed with natural gas

and petroleum deposits. Propane

is one of the many fossil fuels

included in the liquefied

petroleum gas (LPG) family.

Propane is a very clean burning fossil fuel, which explains its use in indoor


National Energy Policy Act of 1992.

Propane undergoes combustion reactions in a similar fashion to other

. In the presence of excess oxygen, propane burns to form water and

→ 3 CO2 + 4 H2O + heat

→ carbon dioxide + water


incomplete combustion occur when propane burns and forms water,

carbon dioxide, and carbon.

→ 2 CO2 + 2 CO + 2 C + 8 H2O + heat

→ Carbon dioxide + Carbon monoxide + Carbon +



has a Capacity of 95 MT, storing propane in both liquid and gas form. On an




h temperature increase. Also bullet tank is designed with huge

thickness to withstand any expansion or explosion.

hich explains its use in indoor


reactions in a similar fashion to other

. In the presence of excess oxygen, propane burns to form water and


incomplete combustion occur when propane burns and forms water, carbon

Carbon monoxide + Carbon +



and gas form. On an




h temperature increase. Also bullet tank is designed with huge


Propane has a physical property, that Liquefied1ml of Propane occupies

270 ml in Gaseous form, therefore all propane users use propane eithe

completely in liquid form or partly gas and partly liquid form, In HMIL propane

bullet stores in both liquid form and gas

form, because plane needs gaseous form,

and it is expensive to boil liquid propane

into gas continuously.

The plant needs propane supply at

a pressure of 3 kg/cm2 continuously. The

pressure levels are maintained by

and By-Pass valves. Vaporiser is used to

heat the liquid propane to its boiling

point and vaporise it. It is done by heating

the water up to 85oC and it heats the

propane. Vaporiser is used only if the propane gas form goes insufficient in the

bullet, which is compromised by the liquid propane. The yard has three modes

of colour codes in piping arrangement. They are

• Plain Yellow.

• Plain Yellow with Red Band.

• Plain Red.

Plain Yellow carries propane in pure liquid form. Plain yellow with red

band carries propane in vapour form, and the plain red carries fire water for

emergency purposes.

The yard gets its propane source from tankers which come

load the Bullets. Initially, the tanker is at high pressure than the bullet. Hence,

liquid propane unloads from the

tanker into the bullet until the

pressure in the tanker equals that

of the bullet. Then the

compressor pushes the vapour

from the bullet to the tanker and

pressurises the remaining liquid

propane into the bullet. Once the

liquid propane is completely filled

into the bullet, the compressor loads compressed air into the tanker to empty

the vapour propane to the bullet. Thus unloadin

Fire fighting is supposed to be very important in any industry and its

importance is almost equal to the importance which is given to production and

profit. There are several methods of fire fighting used at HMIL. Since, propane


270 ml in Gaseous form, therefore all propane users use propane eithe


bullet stores in both liquid form and gas

form, because plane needs gaseous form,

and it is expensive to boil liquid propane

The plant needs propane supply at

continuously. The

pressure levels are maintained by PRV

Vaporiser is used to

heat the liquid propane to its boiling

point and vaporise it. It is done by heating

C and it heats the



of colour codes in piping arrangement. They are

th Red Band.



The yard gets its propane source from tankers which come

Initially, the tanker is at high pressure than the bullet. Hence,

liquid propane unloads from the

tanker into the bullet until the

pressure in the tanker equals that

of the bullet. Then the

compressor pushes the vapour

he bullet to the tanker and

pressurises the remaining liquid

propane into the bullet. Once the

liquid propane is completely filled


the vapour propane to the bullet. Thus unloading is done into the bullets.

is supposed to be very important in any industry and its




270 ml in Gaseous form, therefore all propane users use propane either






The yard gets its propane source from tankers which come regularly to

Initially, the tanker is at high pressure than the bullet. Hence,


g is done into the bullets.

is supposed to be very important in any industry and its




is an explosive gas, the yard has large amount of precautions in fire fighting

process. The yard is planted with 24 sensors to notify the temperature and

any propane leakage. Innumerable fire alarms and sprinklers are implanted in

various parts of the Yard. Also at the top of the bullets, automated fire

extinguisher is fixed to quench the fire at the top, in case fire can’t be

controlled manually. In addition to this, external Hydrant is in practise. All the

activation of fire fighting systems are situated in separate portion, on water

treatment plant part with Jockey, Spray, and Hydrant pumps for respective

activation. All are automated pumps.

USES OF PROPANE: Heat is produced when propane undergoes combustion, which is used

for several parts of the HMIL. They are

� Drying paints

� Heat treatment in hardening of gears

� Melting aluminium ingots

� Canteen

� Boilers furnace pilot firing

PROPERTIES OF PROPANE:

1. Molecular weight - 44.097.

2. Specific Gravity - 1.52.

3. Specific Volume - 0.552 m3/kg.

4. Density - 580 kg/ m3.

5. Specific Heat - 1630 J/kg.K.

6. Specific Heat Ratio - 1.2

7. Gas Constant - 188 J/kg.C

8. Latent Heat of Evaporation - 428000 J/kg.

9. Flammable - Yes.

10. Heat of Combustion - 50340 kJ/kg.


WATER TREATMENT AND SUPPLY

WATER TREATMENT PLANT:

HMIL meets its water requirements from the water treatment plant. The

plant supplies treated water to all parts of the HMIL. At first, raw water storage

tank gets water from outside sources and it stores it. The outside sources are

• Chembarambakkam Lake.

• Rain water storage.

The capacity of the raw water tank is 2000kL. The water from there is

pumped for pre-treatment. The water passes through

in which chemicals such as Sodium hydroxide and poly aluminium chloride are

used to decrease the turbidity, and it is passed

through layers of filters, which vary with their

porosity and it filters out the dust and remains in the

water. Thus the filters reduce the

filter must be cleaned with backwash method, to

avoid blockage of water inside the filters. During the

process of backwash, the outlet is closed, and inlet

is switched to outlet portion, and water flows in

reverse, peeling the sediments out.

The water from there is stored in two separate

tanks, in which one is called treated water tank

which is used for canteen purposes, and other is

called recycled or industrial storage, used for

industrial purposes.

DEMINERALIZATION PLANT:

Water from industrial storage can be used for cleaning, cooling, etc.. But

for boilers, the water must be de

corrosion, scale formation, inside the boiler parts when the water boils.

Therefore, De-Mineralization plant supplies demineralised water to boiler feed

supply.


WATER TREATMENT PLANT:

eets its water requirements from the water treatment plant. The



Chembarambakkam Lake.

er storage.


treatment. The water passes through MGF (Multi Grade Filter)


used to decrease the turbidity, and it is passed

through layers of filters, which vary with their

porosity and it filters out the dust and remains in the

r. Thus the filters reduce the Turbidity. The

filter must be cleaned with backwash method, to

avoid blockage of water inside the filters. During the

, the outlet is closed, and inlet

is switched to outlet portion, and water flows in

reverse, peeling the sediments out.

The water from there is stored in two separate

tanks, in which one is called treated water tank

which is used for canteen purposes, and other is

called recycled or industrial storage, used for

ERALIZATION PLANT:


for boilers, the water must be de-mineralized, because the minerals may cause


Mineralization plant supplies demineralised water to boiler feed


eets its water requirements from the water treatment plant. The




(Multi Grade Filter)



mineralized, because the minerals may cause


Mineralization plant supplies demineralised water to boiler feed


Ion exchange resins

methodology used to demineralise the water.

There are two types of resins called Anion

exchange resin and Cation exchange resin.

Anion resin removes all anions from water,

such as Cl,I,Br,S etc..in exchange of OH ions,

and Cation resin removes all cations from

water , such as Ca,Mg,Na,Al etc...in exchange

with H ions. It is done by insoluble,cross

linked, long chained polymers with a micro

porous structure and the functional groups attached to them in the resins

which are responsible for the reaction and removal of ions from Water.

The components in the

base anion(WBA), Degasser

strong base anion (SBA). The outlet of the SBA

is the DM water which is used in the boilers.

The regeneration of SAC is being done with

Hydrochloric acid, WBA,SBA is being done with

Sodium hydroxide. The regenerated sludge is

neutralized and proposed to waste wat

treatment plant for further treatment.

The parameters that are changed by the DM plant are

• PH (alkaline).

• Hardness.

• Turbidity.

• Conductivity.

• TDS(Total dissolved solids).

FIRE PUMPS:

Besides treating water for Industrial purposes, it also pumps wat

fire fighting system all around the plant in automated way. The Water

Treatment plant has pumps for fire fighting system. They are

• Hydrant Pump

• Spray Pump

• Jockey pump

Ion exchange resins are the basic

methodology used to demineralise the water.

There are two types of resins called Anion

exchange resin and Cation exchange resin.

removes all anions from water,

such as Cl,I,Br,S etc..in exchange of OH ions,

and Cation resin removes all cations from

water , such as Ca,Mg,Na,Al etc...in exchange

with H ions. It is done by insoluble,cross

linked, long chained polymers with a micro

ous structure and the functional groups attached to them in the resins


The components in the DM plant are strong acid Cation

Degasser tower and the

base anion (SBA). The outlet of the SBA

is the DM water which is used in the boilers.

The regeneration of SAC is being done with

Hydrochloric acid, WBA,SBA is being done with

Sodium hydroxide. The regenerated sludge is

neutralized and proposed to waste water

treatment plant for further treatment.

The parameters that are changed by the DM plant are

TDS(Total dissolved solids).

Besides treating water for Industrial purposes, it also pumps wat


Treatment plant has pumps for fire fighting system. They are

ous structure and the functional groups attached to them in the resins


strong acid Cation (SAC),weak

Besides treating water for Industrial purposes, it also pumps water to all the



Hydrant Pump:

There are three pumps which is always kept in ON condition. In case of

fire incidents there will be heavy pressure losses inside the pipe line. To

increase the pressure all the three pumps are switched on automatically. This

pump discharges 171 m3/hr.

Spray Pump:

Spray Pump builds pressure for water sprinklers and supplies water to

them. In case of fire accidents, the quartzite bulb detects the temperature rise

immediately and pump valves are opened automatically. The pump covers

propane yard, substation, paint shop.

Jockey Pump:

The main use of this pump is to maintain pressure in the fire fighting

water pipes, which automatically detects the loss of pressure in the pipe and

builds pressure automatically.


BOILER PLANT

STEAM: Steam is vaporised water, being part gas, part liquid. Steam itself is

usually interspersed with minute droplets of water in its liquid state, which

gives it a white, cloudy appearance. In industrial and process situations, steam

is often generated using water boilers that are heated to create steam under

controlled conditions. The energy generated is then transferred and used in

many different ways.

BOILERS: HMIL needs steam at high pressure for industrial purposes. There are

two types of boilers in HMIL, they are

• Fire Tube Boiler (FTB).

• Water Tube Boiler

FTB: A fire-tube boiler is a type of

which hot gases from a fire pass through one

or more tubes running through a sealed

container of water. The heat

transferred through the walls of the tubes

by thermal conduction, heating the water

and ultimately creating steam

WTB: A water tube boiler

in which water circulates in tubes heated

externally by the fire. Fuel is burned inside

the furnace, creating hot gas which heats

waterin the steam-generating tubes.

smaller boilers, additional generating tubes

are separate in the furnace, while larger

utility boilers rely on the water

that make up the walls of the furnace to

generate steam.

BOILER PLANT

Steam is vaporised water, being part gas, part liquid. Steam itself is




s. The energy generated is then transferred and used in

HMIL needs steam at high pressure for industrial purposes. There are

two types of boilers in HMIL, they are

(FTB).

(WTB).

is a type of boiler in

which hot gases from a fire pass through one

or more tubes running through a sealed

heat of the gases is

transferred through the walls of the tubes

, heating the water

steam.

water tube boiler is a type of boiler

in which water circulates in tubes heated

externally by the fire. Fuel is burned inside

, creating hot gas which heats

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

Steam is vaporised water, being part gas, part liquid. Steam itself is




s. The energy generated is then transferred and used in

HMIL needs steam at high pressure for industrial purposes. There are


PARTS OF BOILER: Boiler contains innumerable parts associated in the process; the

following are core machinery processes involved in the steam generation

process.

1.DEAERATOR:

Deaerator is an important component in

production of steam. Dissolved gase

and carbon dioxide are initially present in the feed

water. If these gases are not removed, they can line

the surfaces within the boiler and cause accelerated

corrosion. Since these gases cannot be condensed out.

A deaerator utilizes

dissolved oxygen, carbon dioxide, and other non

condensable gases from boiler feed water. The feed

water is sprayed in thin films into a steam atmosphere

allowing it to become quickly heated to saturation. Spraying feed water in thin

films increases the surface area of the liquid in contact with the steam, which,

in turn, provides more rapid oxygen removal and lower gas concentrations.

This process reduces the solubility of all dissolved gases and removes it from

the feed water. The liberated gases are then vented from the deaerator. In this

process, addition of Hydrazine is done to improve the efficiency.

2.ECONOMIZER:

Economizer is the core of the

boiler, where the fire from oil heats up

the water into steam. Latter, economizer

is also employed to utilize the waste

heat generated from the combustion

process to improve overall efficiency in

the boiler. Flue gas exiting the

combustion chamber is still, Very hot

and can be used as a pre

these boilers is a horizontal counter current shell and tube heat exchanger.

Feed water enters finned tubes while hot flue gases pass over the outside. This

allows for the recovery of energy which would otherwise be wasted.

Boiler contains innumerable parts associated in the process; the


Deaerator is an important component in

production of steam. Dissolved gases such as oxygen

and carbon dioxide are initially present in the feed

water. If these gases are not removed, they can line

the surfaces within the boiler and cause accelerated

corrosion. Since these gases cannot be condensed out.

A deaerator utilizes Henry’s law to remove

dissolved oxygen, carbon dioxide, and other non-

condensable gases from boiler feed water. The feed

water is sprayed in thin films into a steam atmosphere


ms increases the surface area of the liquid in contact with the steam, which,



ated gases are then vented from the deaerator. In this


Economizer is the core of the

boiler, where the fire from oil heats up

the water into steam. Latter, economizer

also employed to utilize the waste

heat generated from the combustion

process to improve overall efficiency in

the boiler. Flue gas exiting the

combustion chamber is still, Very hot

and can be used as a pre-heater for the feed water. The economizer used fo




Boiler contains innumerable parts associated in the process; the



ms increases the surface area of the liquid in contact with the steam, which,



ated gases are then vented from the deaerator. In this


heater for the feed water. The economizer used for





3.FURNACE and FLUE GAS:

Flue gas is the main heating element of the boiler. It is formed in the

furnace by atomising the oil into particles with compressed air, and igniting

them up to 1500oC. The oil is being pumped into finned tubes, where oil

atomised and mixes with compressed ai

numerous no of thin tubes into the water tank, slowly temperature of the flue

gas gets reduced to 350oC at the end of the economizer.

4.BLOW DOWN:

Dissolved solids and particles entering a boiler through the make

water will remain behind when steam is generated. During operation the

concentration of solids build up and finally a

concentration level is reached where operation

of the boiler becomes impossible.

Blowdown is a common procedure for a

boiler to control the contaminants in the boiling

water. Two types of blowdown exist, manual and

continuous. For a continuous blow down, a

Calibrated valve continuously takes water from

the top of the boiling surface in the steam drum. Manual blowdown is

accomplished through tap

are removed. With manual blowdown water level control devices and cut off

devices are kept clean of any solids interfering with their operation.

PRODUCTION OF STEAM: The basic principle behind the pro

heated, heated, and post heated by fire, there exists two path ways in this

production, one describes how water converts into steam, whereas another

goes with how air becomes flue gas.

Water – Steam:

From the De Mineralization plant water enters Feed water storage tank,

which primarily stores water required for steam formation, from there using

raw water pump it is pumped to deaerator. From Deaerator water enters

economizer to heat up, the hotter water passes into Ba

muddrum and passing through rifer tube where it finally converts into steam,

the steam gets stored at Steam Drum (Steam Receiver).

3.FURNACE and FLUE GAS:

e gas is the main heating element of the boiler. It is formed in the


C. The oil is being pumped into finned tubes, where oil

atomised and mixes with compressed air. The flue gas passes through a


C at the end of the economizer.

Dissolved solids and particles entering a boiler through the make

r will remain behind when steam is generated. During operation the

concentration of solids build up and finally a

concentration level is reached where operation

of the boiler becomes impossible.

Blowdown is a common procedure for a

ontaminants in the boiling

water. Two types of blowdown exist, manual and

continuous. For a continuous blow down, a

Calibrated valve continuously takes water from


accomplished through tapings at the bottom of the boiler where solids settled



PRODUCTION OF STEAM: The basic principle behind the production of steam, is that water is pre



goes with how air becomes flue gas.

eralization plant water enters Feed water storage tank,



economizer to heat up, the hotter water passes into Bank tube, then to


the steam gets stored at Steam Drum (Steam Receiver).

e gas is the main heating element of the boiler. It is formed in the


C. The oil is being pumped into finned tubes, where oil

r. The flue gas passes through a


Dissolved solids and particles entering a boiler through the make-up

r will remain behind when steam is generated. During operation the


ings at the bottom of the boiler where solids settled



duction of steam, is that water is pre-



eralization plant water enters Feed water storage tank,



nk tube, then to



Air–Flue gas:

The atmospheric air is compressed and passed through Forced Drafter

and mixes with atomised oil particles and ignited at the inlet of economizer to

give flue gas which heats water inside the Economizer, part of the flue gas is

reused to its maximum efficiency, and then passed onto the chimney, from

where it leaves outside.

OUTPUT and CONTROL OF BOILER:

The WTB provides steam at 198°C and at 14 kg/cm2pressure, whereas

FTB delivers steam at around 180°C and at 10.54 kg/cm2pressure. Pressure

Gauges are located at the inlet and at Steam drum to record the pressure of

steam continuously. Safety valve and Stop valves are fitted in the boilers in

case of emergency purposes. Air vent is a valve, which is opened to remove air

from free air left in Boiler. The flue gas leaving the chimney contains a lot of

heat energy, which could be reused; modern boilers are more efficient in

utilising the heat energy to the maximum extent.

The steam produced in the boiler is used in

• Paint Shop

• Canteen

• Engine Shop

• Waste Water evaporation Unit


CENTRIFUGAL COMPRESSORS

ABOUT CENTRIFUGAL COMPRESSORS (CC):

A compressor is a piece of machinery that compresses a fluid, a liquid or

a gas, that flows in the compressor into greater pressure. As the pressure of

the fluid rises, the fluid flows through the compressor from lower pressure into

higher pressure. Compres

referred as blowers.

Centrifugal compressors use the rotating action of an

exert centrifugal force on air inside a round chamber (volute). Air is sucked into

the impeller wheel through a large circular intake and flows between the

impellers. The impellers force the air outward, exerting centrifugal force on the

air. The air is pressurized as it is forced against the sides of the volute.

Centrifugal compressors are well suited to compressing large volumes of air to

relatively low pressures. The compressive force generated by an impeller

wheel is small, so chillers that us

more than one impeller wheel, arranged in series. Centrifugal compressors are

desirable for their simple design and few moving part.

Compressors are used in Hyundai Motor India limited to provide

compressed air to meet their requirements in various fields.

acts like a heart in heart, an ultimate source of energy next to electricity in this

industry. It is used for air filling, drying, for pneumatic applications, painting

etc, to meet the compressed a

Ingersoll Rand Centrifugal Compressors

PARTS OF THE CENTRIFUGAL COMPRESSOR:


ABOUT CENTRIFUGAL COMPRESSORS (CC):

compressor is a piece of machinery that compresses a fluid, a liquid or



higher pressure. Compressors working in a small pressure ratio can also be

Centrifugal compressors use the rotating action of an impeller




air is pressurized as it is forced against the sides of the volute.



wheel is small, so chillers that use centrifugal compressors usually employ


desirable for their simple design and few moving part.


meet their requirements in various fields.



ompressed air requirements of the industry. At HMIL,

Ingersoll Rand Centrifugal Compressors are used.

PARTS OF THE CENTRIFUGAL COMPRESSOR:


compressor is a piece of machinery that compresses a fluid, a liquid or



sors working in a small pressure ratio can also be

impeller wheel to




air is pressurized as it is forced against the sides of the volute.



e centrifugal compressors usually employ



Compressed air



ir requirements of the industry. At HMIL,


Inlet:

The inlet to a centrifugal compressor is typically a simple pipe. It includes

features such as a valve, stationary vanes and their respective instrumentation.

All of these additional devices have important uses in the control of the

centrifugal compressor.

Centrifugal Impeller:

The key component that makes a compressor centrifugal is the

centrifugal impeller. It is the impeller's rotating set of vanes that gradually

raises the energy of the working gas by imparting their kinetic energy. In many

modern high-efficiency centrifugal compressors the gas exiting the impeller is

travelling near the speed of sound.

Impellers are designed in many

configurations including open (visible blades),

covered or shrouded, with splitters (every other

inducer removed) and without splitters (all full

blades). Most modern high efficiency impellers

use back sweep in the blade shape.

Diffuser:

The next key component to the simple

centrifugal compressor is the diffuser. Downstream of

the impeller in the flow path, it is the diffuser's

responsibility to convert the kinetic energy of the gas

into pressure by gradually diffusing the gas velocity.

Diffusers can be vane less, vaned or an alternating

combination Bernoulli's fluid dynamic principal plays

an important role in understanding diffuser

performance.

Coolers:

The Centrifugal Compressor is equipped with Water coolers and Oil

coolers to absorb the enormous heat energy produced and stored in air when

it is compressed. The coolers swirl around the air pipe and by indirect means of

heat exchange, it cools down the air. The coolers are further classified into

Inter Cooler and After Cooler, with name implying its meaning that inter cooler

cools in between the stages of compressor, and after cooler cools after

completion of all stages.


Centrifugal compressor(Ingersoll-Rand) parameters

Discharge pressure 7.0 kg/cm2

Discharge Flow 132 NM3/min

Shaft power at coupling for FAD 132 NM3/min(dry) 753.5 kW

Shaft power at coupling for FAD 132 NM3/min 709.3 kW

Installed motor power in kW 900 kW

Actual turn down ratio Above 25%

Compressor Inlet Conditions

Suction pressure 1.013 bar

Inlet pressure 0.994 bar

Inlet air temperature 45oC

Relative humidity 80%

Cooling water temperature 35oC

Compressed Air-Phase I Compressed Air-Phase II

Centrifugal Compressors 4*132 NM3/min 5*132 NM

3/min

1*60 NM3/min

Screw Compressors 5*50 NM3/min 1*50 NM

3/min

1*60 NM3/min

Total Capacity 778 NM3/min 720 NM

3/min

Present Consumption 580 NM3/min 446 NM

3/min


WORKING OF CENTRIFUGAL COMPRESSORS:

Atmospheric air is brought to the inlet of the CC by using suction inlets.

The sucked air is passed through primary and secondary filters, to absorb the

dust and particulates. The filtered air passes through three stages of the CC.

In the first stage the air is passed to the impeller, in which the air is

circulated and it gains Kinetic energy and goes through the diffuser to convert

the kinetic energy into Pressure energy. The pressure rises from 0.994 bar to

1.5 bar. During this process, the temperature of air raises dramatically up to

150oC. Then the hot air passes through the Inter Cooler 1, in which the cooling

water passes around the hot air, and cools it down, back to the Inlet

Temperature without changing the pressure.

In the second stage , the air goes through the second impeller and

diffuser to raise its pressure from 1.5 to 3.5bar approximately, once again an

Inter cooler is set up to bring back the temperature to its Inlet Point without

changing the pressure.

In the final third stage, pressurized air goes through the third impeller

and diffuser and it goes through an After Cooler to cool down its temperature

in similar to Inter Cooler, except that the final temperature from the After

Cooler is slightly above than that of Inter Cooler. In this stage, the Pressure

rises from 3.5 to 6.5bar, and reaches outlet.

Apart from inter cooler and after cooler, there exists also Oil cooler

which takes part in the cooling of compressed air. All the coolers in the

centrifugal compressor do not make contact with the compressed air, so no

contact with the coolants. The amount of water and oil flow in these coolers is

TYPE OF COOLER CONSUMPTION

Inter Cooler 78.8 M3/hr

After Cooler 27.3 M3/hr

Oil Cooler 17 M3/hr


The cooling water is being purified and recycled and pumped back to

compressor throughout the process, also the water is been added certain

chemicals to reduce corrosion of materials inside the inter cooler, and to avoid

any formation of algae inside the machinery which would be a lot difficult to

clean manually.

Atmospheric air contains a huge amount of moisture (around 80%

relative Humidity). When air gets cooled at Inter and after cooler, the moisture

gets condensed to water. Therefore both inter and after cooler condense a

large amount of water during the compression process, which are drained to

water treatment plant in HMIL.

Even after this, Compressed air contains a particular amount of

moisture, which is needed to be removed. It is done by the use of Dryers. The

basic principle behind the working of Dryers is that, when the dry air with

moisture comes in contact with the cooled water, moisture condenses out as

water droplets. There are two types of dryers in practise in HMIL. They are


1. Refrigeration Dryers. (Absorbs up to 90 percent of the

moisture content)

Compressed Air Quality - Refrigeration Dryer outlet

Pressure 5.8-6.2 kg/cm2

Dew Point Below (-)20oC

Dust Size Less than 0.5 µm (Oil free Air)

2. Adsorption Dryers. (Absorbs 99.9 percent of the moisture content,

particularly used for compressed air to paint shops, where there is no

compromise for moisture)

Compressed Air Quality – Adsorption Dryer Outlet

Pressure 5.8-6.2 kg/cm2

Dew Point Below (-)40oC

Dust Size Less than 0.01µm (Oil Free Air)

PERFORMANCE AND CONTROL OF CC.

To monitor the CC, it is to

be designed with Pressure Ratio π

(the ratio between the Discharge

pressure and inlet pressure), Flow

rate which is either mass flow rate

or volumetric flow. The primary

source of power to run the CC is

the Motor Input to the Centrifugal

Impeller, the secondary sources

include the inter and after cooler motor inputs, suction power supply and

power for digitally recording operating parameters.

Basically the capacity control is achieved by inlet throttling or inlet guide

vane control. For a given impeller design and speed of operation, the pressure


ratio varies with the volume. The power consumption increases as the volume

increases.

When the flow demand fluctuates, constant pressure has to be

maintained at the discharge. When flow demand reduces, inlet valve is

throttled; keeping the bypass valve closed and the air flow will follow the

straight line, keeping the pressure constant. However, this throttling is done

only up to the point which is only marginally above the surge limit. Any further

reduction in flow will result in the compressor operating in the surge region. At

this point, if the flow demand is still reducing, the bypass valve is kept open by

the signal from the surge sensor. The compressor now blows off surplus air

thorough the bypass valve for flow requirements. Evidently, this mode of

control is not energy efficient although surging is avoided. This mode of

operation is used when system demand is more than 50% of the compressor

capacity and is fairly constant.

Use of movable inlet guide vanes is a better method of capacity control

in centrifugal compressors, the movable inlet guide vanes add pre-whirl to the

gas stream entering the impeller. By modifying the inlet whirl component, drop

in efficiency is very little. It may be noted that the specific power consumption

remains essentially the same for flow variation from 100% to 70%.

FAD of CC.

FAD (Free Air Delivery) of an air compressor is the air sucked in by the

compressor at standard condition. The specific power consumption

(kW/100scfm) is a good figure of merit to evaluate the performance of

compressors, It may be noted that centrifugal compressors are the most

efficient Compressors compared to screw and Reciprocating. The formula for

calculating FAD is

�� = �� − � ∗ � ∗ � ∗ � ∗ �

Where P2 – final pressure of the receiver.

P1 - inlet pressure of the compressor.

V –Volume of the receiver.

T1 – Inlet temperature in Kelvin.

T2 – Compressed air temperature in Kelvin.

T – time taken to fill the receiver at working pressure of the system.

The design value FAD of Centrifugal Compressor in HMIL is 132 �� .The

difference between measured FAD and designed FAD should not exceed 20%

of the value which is 26.4. If not, then compressor needs a check up.


CENTRIFUGAL COMPRESSOR INSTABILITIES:

Surge:

Surge is an instability that affects the entire compression system. Surge

is characterized by a limit cycle

oscillation that results in large

amplitude fluctuations of the

pressure and flow rate. In contrast

to rotating stall, during surge the

average mass flow is unsteady but

circumferentially uniform. In other

words, surge is one dimensional

system instability while rotating stall

is two-dimensional compressor

instability. Furthermore, surge only

occurs in compressible flow systems whereas rotating stall occurs in both

incompressible and compressible flow.

As mentioned before, surge results in considerable loss of performance

and efficiency. Furthermore, the power level of the pressure oscillations can

approach that of the compressor itself, inducing large mechanical loads on the

entire compression system. The main Reasons behind the formation of Surge

are

• Low Inlet Pressure

• High Discharge pressure.

• High Inlet Temperature.

• Tear and worn of machinery parts.

• Improper functioning of machine parts.

The basic techniques for surge avoidance are:

• Improved aerodynamic design in Air flowing paths.

• Reduction of variations in operating conditions.

• Inclusion of components that supporting the flow, not obstructing

the flow

• Active suppression of aerodynamic instabilities (if any).


Rotating Stall:

Rotating stall is an aerodynamic instability confined to the compressor

internals that is characterized by

pattern. One or more regions of stagnant

around the circumference of the compressor at 10

The stall cells reduce or completely block the

stresses and thermal loads on the compressor blades. While the effects of

rotating stall are known, details of stalled

cells, their size and speed relative to the impeller, are far from being

completely understood.

Given its distorting effect on the

flow, rotating stall can result in a large

drop in performance and efficiency.

Rotating stall introduces a gradual or

abrupt drop of the pressure rise.

Moreover, rotating stall can introduce

hysteresis into the system, implying that

the flow rate has to be increased

beyond the stall initiation point in order

to bring the compression system out of

its stalled operating mode.

otating stall is an aerodynamic instability confined to the compressor

internals that is characterized by a distortion of the circumferential

pattern. One or more regions of stagnant flow, so-called stall cells, travel

around the circumference of the compressor at 10–90% of the shaft speed.

The stall cells reduce or completely block the flow, resulting in l


rotating stall are known, details of stalled flow, for example the number of stall


Given its distorting effect on the

ow, rotating stall can result in a large

drop in performance and efficiency.

Rotating stall introduces a gradual or

abrupt drop of the pressure rise.

Moreover, rotating stall can introduce

system, implying that

flow rate has to be increased

beyond the stall initiation point in order

to bring the compression system out of

its stalled operating mode.

otating stall is an aerodynamic instability confined to the compressor

a distortion of the circumferential flow

called stall cells, travel

90% of the shaft speed.

flow, resulting in large vibratory


flow, for example the number of stall



EFFICIENCY OF THE CC:

The efficiency of the machine is how much output does it give related to

our given input. In the case of Centrifugal Compressor, the efficiency is

calculated in many ways.

• Volumetric Efficiency.

• Isentropic Efficiency.

• Polytropic Efficiency.

Volumetric Efficiency:

Volumetric Efficiency is the ratio of Net Volume flow into the

compressor to the compressor design flow. Compressor Design flow is a

function of the impeller design flow coefficient, its speed and diameter and is

inclusive of all leakages. Volumetric efficiency can then be defined as follows,

�� = �� !"��.

The Compressor design volume flow depends on Flow coefficient, Speed,

and Diameter of the impeller. The equation follows as,

�� !"�� = �� # �"� ∗ $�� ∗� ��.

Net Volumetric Flow (or flange-to-flange flow) is Compressor design flow

minus the internal leakages i.e. balance piston and centre seal leakages

whichever is applicable.

Design flow = 5525.0802cfm.

Net flow = 5445.2580cfm.

Leakages = 5525.0802cfm – 5445.2580cfm = 120.778cfm

Therefore %&'( = )**).�)+,))�).,+,� = 99.94%.

The volumetric efficiency will be close to 100 % in factory test and lower in

the field depending upon application, operating pressures and sizes of the

machine and pressure ratios etc. This concept can help to explain some of flow

anomalies found during field tests and reconcile the differences in head,

efficiency and power found in field tests.


Isentropic Efficiency: The isentropic efficiency expresses how much the compression process

resembles an isentropic compression process. When the value of efficiency is

one, the compression process is an ideal process, which has no losses.

Isentropic efficiency is defined by calculating the change in specific enthalpy in

the real compression process and comparing it to the change in specific

enthalpy in an ideal compression process. Isentropic efficiency is calculated

throughout the whole compressor system.

Isentropic efficiency “µ” for a compression process can be calculated with the

equation

� = �� − � �� − ��

Where “c1” is the specific heat capacity in average temperature of an ideal

isentropic compression process, T2ideal is the outtake temperature in an

isentropic compression process, T1 is the intake temperature, “c2” is the

specific heat capacity in constant pressure computed in average temperature

of a real compression process and T2real is the outtake temperature in a real

compression process.

Applying, adiabatic conditions to the process, we get,

Theoretical Power (kW) =

- ∗ $ ∗ .� ∗ / ∗ 01.�.�2�-3∗$- − 4 �- − ∗ 5�,.6

Where S= no of stages.

K=adiabatic constant of air.

Ps=Suction pressure.

Pd=Discharge pressure.

Q=FAD.

CALCULATION OF ISENTROPIC EFFICIENCY OF 3 DIFFERENT STAGES OF

CENTRIFUGAL COMPRESSOR.

*Motor input Power (kW) = 776.35 kW.


*Motor Efficiency, µ7898: = 96.2%.

*Real Power = 776.35 * ;<.=>??.= 746.85 kW.

*K≈ 1.4

*S = 1. (Since the formula is applicable for only compression process, cooling is

not involved, we calculate the efficiency stage wise.).

*Q = 132CD/min.

*EF = 0.994IJK.

*EL = 1.5 bar for stage 1,

3.5 bar for stage 2,

6.5 bar for stage 3.

Substituting the data to the above formula, we get

Theoretical Power for Stage 1:

E9MN,> = >∗>.P∗?.;;P∗>D=∗Q1 R.S.TTU2V.UR.UW>X

?.P∗<>=? = 92.62 kW


E9MN,= = >∗>.P∗>.Y∗>D=∗Q1Z.SR.S2V.UR.UW>X

?.P∗<>=? = 287.8 kW


E9MN,D = >∗>.P∗D.Y∗>D=∗Q1[.SZ.S2V.UR.UW>X

?.P∗<>=? = 105.0 kW

Therefore, the corresponding Isentropic Efficiencies are


Stage 1:

µ=;=.<=\P<.]Y

µ= 12%.

Stage 2:

µ==]\.]Y\P<.]Y

µ= 38.5%

Stage 3:

µ=>?Y\P<.]Y

µ=14%

Polytropic Efficiency:

The Polytropic efficiency expresses how much the real compression

process resembles an ideal compression process, but different from isentropic

efficiency, the Polytropic efficiency is defined across a differential part in the

system, and so calculated through the whole system. Polytropic efficiency can

be calculated by assuming that in an ideal process the temperature ratio is

relative to the pressure ratio according to equation

� =.��̂�.�̂�

Where p2 is the outtake pressure,p1 is the intake pressure and R is the specific

gas constant of the fluid. When calculating a real compression process, the

Polytropic efficiency is included in the equation by adding it to the exponent

“_"according to the equation,


� =.��-W�-.�-W�-

The Polytropic efficiency is better for compressor comparison than the

isentropic efficiency, because the value of the Polytropic efficiency does not

change as much as the value of the isentropic efficiency does. It is possible to

have the same value of Polytropic efficiency for two different compressors

working in the same conditions. The greater the pressure ratio, the more the

isentropic and Polytropic efficiency values differ.

We can find the _by substituting the values found out by experimentally

observed. Consider Stage 1, where pressure increases from 1bar to 1.5 bar,

and temperature raises from 300°K to around 420°K.On Substituting these

values we get .��a�� #b�� # �"#acdKefJgh1"_"(with K=1.4) as

ln k=k> = �l − 1l_> ln E=E>

ln 420300 = 0.41.4_> ln 1.50.994

� = ,. �*p*.

Likewise, Efficiency for stage 2 and 3 are calculated with its parameters. We

get,

�� = ,. qp).

�� = ,. )�*.

From both isentropic efficiency and polytrophic efficiency one could notice

that, even though the value of efficiencies differ, the order of efficiency

doesn’t change i.e. Second stage is most efficient and first stage is least

efficient, which depicts on the magnitude of Pressure Ratio.


IMPROVING INLET CONDITIONS:

Improving Inlet conditions is basically increases the performance of the

compressor and its efficiency. Efficiency is a ratio between ideal process value

and its real process value, in every practical purpose the real value will be

always less than the ideal value. That’s why the efficiency never be 100%. The

efficiency of the centrifugal compressor depends on various parameters, and

there are many methods which could increase the efficiency of the

compressors. But the problem associated with that is that all methods

wouldn’t be suitable in either cost, space, energy, etc..That’s why optimizing

efficiency means us the meaner and fitter methods of better performance to

the compressor.

We choose two basic methods to reduce the power usage of the

compressor. They are

• Pre Cooled Air intake.

• Humidity Reduction.

Both of the methods actually inter relate to each other in a complex

way. In an approximate way, it can be said that, cooling of air takes place

easier at low humidity.

PRE-COOLED AIR INTAKE:

In general, air at ambient conditions is sucked in for compression. Due to

this the compressor had to work more particularly during summer and

monsoon period, because of high temperature and moisture content of

ambient air. By cooling the air entering the compressor, the efficiency of the

compressor can be improved which will reduce the energy consumption for

generating the same quantity of compressed air. This cooling is achieved by

sucking the air though a refrigeration dryer unit. As the temperature of air is

reduced, its volume also decreases per unit mass and a greater mass of air is

available for the given compressor work. Therefore, due to pre cooling either

more air is delivered for a given power input or the power input is reduced for

a required volumetric flow rate.

The moisture present in inlet air is condensed out giving dry air for

compression and saving energy, which would otherwise be used for

compressing water vapour. This will also reduce the wear and tear of the

moving parts in the compressor. The dust present in the air is entrained in the

ice during freezing. This acts as a filter eliminating the need for a conventional

filter and its inherent flow resistance, leading to further energy as well as

capital cost savings.


The work for the coolers and dryers are also reduced in this case. This

represents another capital cost saving as well as an additional energy-saving

device. It is estimated that for every 3°C drop in suction air temperature

improves the compressor efficiency by 1%. Installing of exhaust fans could

make the cooling part easier and fast.

Assume the Temperature gets reduced by ∆T, therefore savings in

specific energy is

b� −b= s ∗ �� ∗ 01.�.�2�-3�- − 4t – s� − ∆u ∗ �� ∗ 01.�.�2

�-3�- − 4t =

s∆u ∗ �� ∗ 01.�.�2�-3�- − 4t

Neglecting changes in K and _ due to change in temperature.

Calculations:-

Finding the Savings in specific energy for 1 degree change in temperature,

vw = 1.03 xyxz.{ .

We get specific energy for three stages, as

∆b = 1°K * . ,� |}|!.- * 01 .),.pp*2 .*.*∗.�*p* − 4 = 0.403 kJ/kg.

∆b� = 1°K * . ,� |}|!.- * 01�.).)2 .*.*∗.qp) − 4 = 0.401 kJ/kg.

∆b� = 1°K * . ,� |}|!.- * 015.)�.)2 .*.*∗.)�* − 4 = 0.415 kJ/kg.

Annual Power Savings (theoretically) is = `[∆E * Mass flow rate(kg/hr) * Unit

cost(per kW hour) * 24 * 365].

=`(0.401kJ/kg * 9420.71 7ZM: .∗ >.>PYYxz7Z ∗ [

P.\D<??] * 24 * 365.)

=` 49,490 ≈50,000


Therefore reducing the inlet temperature by 1°K, the annual savings is

`̀̀̀50,000. Up to 15°K redu

as `(`(`(`(50000 * ∆u

DECREASE IN HUMIDITY:

Humidity is nothing but the presence of water vapour in the air. Due to

the presence of humidity in air, compared to dry air work, the work done for

humid air is higher. It is because the water vapour in the air makes its heavy

(by means of increase in their molecular weight).

Humidity is location dependent;

or Madurai, due to the sea shore in Chennai. Therefore on a whole

cannot be suppressed or removed, instead it can be reduced up to certain

extent, for which the expense can be easily renewed in a smaller period with

the power savings given by the compressor in sucking in air with lesser

humidity.

The calculations in this study are made considering the compressed fluid

to be air, but the effects of air humidity have to be considered as well. Humid

air can be considered to be a mixture of dry air and water vapour. In this study

the water vapour is assumed to be near liquefying and humid air is treated as a

perfect gas. Air humidity influences the values of air molecular mass, the

specific gas constant of air and the specific heat capacity of air.

Relative Humidity:

The amount of water vapour in air

vapour in the air. The pressure

of the vapour in the air cannot

be greater than the pressure of

saturated water vapour;

otherwise the water is in liquid

or solid state. Relative humidity

states the relation between the

pressure of the water vapour in

the air and the pressure of

saturated water vapour.

~ � .��


50,000. Up to 15°K reduce in temperature, the savings can be approximated

DECREASE IN HUMIDITY:



s higher. It is because the water vapour in the air makes its heavy

(by means of increase in their molecular weight).

Humidity is location dependent; Chennai has more humidity than T

or Madurai, due to the sea shore in Chennai. Therefore on a whole







sumed to be near liquefying and humid air is treated as a



The amount of water vapour in air is defined by the pressure of the

vapour in the air. The pressure

of the vapour in the air cannot

be greater than the pressure of

saturated water vapour;

otherwise the water is in liquid

or solid state. Relative humidity

states the relation between the

essure of the water vapour in

the air and the pressure of

��/.��


ce in temperature, the savings can be approximated



s higher. It is because the water vapour in the air makes its heavy

Chennai has more humidity than Trichy

or Madurai, due to the sea shore in Chennai. Therefore on a whole humidity







sumed to be near liquefying and humid air is treated as a



is defined by the pressure of the


Where Pvap is the water vapour pressure in the air, Psat is the pressure of the

saturated water vapour and � is the relative humidity.

Specific Heat Capacity :

After calculating the water vapour humidity, the molecular mass and gas

constant can be calculated for the air-water vapour mixture. The molecular

mass for air-water vapour mixture M can be calculated with the mole fraction

of Water vapour “�" given by,

� = .��.��

� = ��9N: ∗ � + ��: ∗ �1 − �

��9N: = 18, ��: = 29.

The gas constant for humid air can be calculated with the equation

where the molecular mass M is now the molecular mass of air-water vapour

mixture.

^ = ^ ��

The specific heat capacity for water vapour can be calculated with the

equation using the constants for water vapour. With the mole fraction of water

vapour in humid air, the specific heat capacity for humid air can be calculated

with the equation.

��, = �� ∗ �� +��a� � ∗ � − �.

v��w8�: = 1.85 xyxz.{ ,

v��: = 1.005 xyxz.{ .

Since , the specific heat capacity of vapour is higher than that of air,

presence of humidity increases the net specific heat capacity, in other words

more the humidity , more the net specific heat capacity. Therefore, the extra

specific energy consumed for compressor,(theoretically) is

�M�7�L −�L:� = [vw,� * ∆T] - [vL:��: * ∆T]


= [ �v��w8�: ∗ �� +�vL:��: ∗ �1 − �]∆T - [vL:��: * ∆T].

= [�v��w8�: − vL:��:) * � * ∆T].

From above, written equations, we get � = �∗�� .

Therefore, Running the Compressor plant at 70% relative humidity

(average relative humidity in Chennai) . In fact, month wise June has the lowest

relative humidity and October has the highest relative humidity, Therefore in

June Compressor should consume lowest power, and in October it should

consume highest power.

And v��w8�: = 1.85 xyxz.{. vL:��: = 1.005 xyxz.{. EF�9= 4.2 X 10DEJ��J�, E989 = 0.994�10YEJ��J�, ∆k = �420°l − 300°l = 120°l. An approximated Temperature difference

for three stages.

b�� −b��a = [ (1.85-1.005) * 1.q,∗*.�∗,,,.pp*∗,,,,,2 * 120 ] = ~� |}|!.

Therefore, its shows for 70%humidity decrease; the specific power

consumption is 3kJ/kg, then for 10% humidity decrease.

∆� = D\? * 10 = 0.428 kJ/kg.

Annual Power Savings is = ` [ ⟨�M�7�L −�L:�⟩ * Mass flow rate(kg/hr) * Unit

cost(per kW hour) * 24 * 365].

=`(0.428kJ/kg * 9420.71 7ZM: .∗ >.>PYYxz7Z ∗ [

P.\D<??] * 24 * 365.)

=`53,110 ≈ `53,000.


An Annual Savings of `̀̀̀53,000 appears on 10%humidty decrease.

TOTAL POWER SAVINGS.

Assume, with 1°C reduction of inlet temperature and humidity decreases

from 70% to 60%, then the theoretically calculated specific energy and power

savings will be

Let,

k> = ¡¢�hffhC£hKJf¤Kh ∆k = Kh¥¤�f¡d¢¡¢¡¢�hffhC£hKJf¤Kh � = ¦h�Jf¡§hℎ¤C¡¥¡f©. �` = «h�KhJ�h¥¦h�Jf¡§hℎ¤C¡¥¡f©. vw,� = e£h�¡c¡�¬hJfdc«K©J¡K. vw,� = e£h�¡c¡�¬hJfdcJfhK®J£d¤K. ¯hf°IhfℎhfhKC ±².�.�³

�-W�- − ´ µ¡fℎELJ¢¥EF¤�¤J�ChJ¢¡¢g,µℎhKh_¡�0.3494�efJgh1

�> = ¶¢¡f¡J�e£h�¡c¡��¢hKg©. �= = ·¡¢J�e£h�¡c¡��¢hKg©.

The following calculation is made with only the First Stage of the compressor,

because from the second stage the temperature may not be as same as in the

first stage.

Calculations: �> = ¸vw,�[1 − �] +vw,��¹ * ° ∗ k>

�= = ¸vw,�[1 − �`] +vw,��`¹ * ° ∗ [k> − ∆k]

�> − �= = ± ¸vw,�[1 − �`] + vw,��`¹ ∗ ∆k−¸vw,�[� − �`] −vw,�[� − �`]¹ ∗ k> ´* °.


Withat60%relhumidity�` = .5,∗*.�∗,,,.pp*∗,,,,, = .02535 J¢¥Jf70%Kh�Jf¡§hℎ¤C¡¥¡f©� = .q,∗*.�∗,,,.pp*∗,,,,, = .02957, J¢¥∆k = 1°v ,

° = 01 >.Y.;;P2 V.U.ZUTU∗R.U − 14 = 0.4

�> − �= = Q É1.005[1 − .02535] + 1.85[.02535]Ê ∗ 1−É1.005[. 02957 − .02535] − 1.85[. 02957 − .02535]Ê ∗ 300 X *.4

= 0.84 |}|!.

Annual Power Savings is = `[ [�> − �=] * Mass flow rate(kg/hr) * Unit cost(per

kW hour) * 24 * 365].

=`(0.84 kJ/kg * 9420.71 7ZM: .∗ >.>PYYxz7Z ∗ [

P.\D<??] * 24 * 365.)

=`1,03,671.04

≈`1,00,000

It is shown from this calculation that combining both methods sums up the

savings approximately.


ACHIEVING BETTER INLET CONDITIONS:

The above mentioned methods to increase compressor performance can

be achieved only with implementing new machineries. The machine which

does this function must reduce the inlet temperature and decrease the

humidity level. Moreover the two methods are dependable on each other.

Reducing the inlet temperature will also reduce the humidity ideally, but

note that it is more difficult to reduce temperature of air at higher humidity

than at lower humidity. Therefore whatever machine that is being

implemented, that must be efficient enough to control both the parameters.

The Machines that more the less perform our desired function are

• Evaporative coolers(Industrial use)

• Chiller Coils.

In general, these are used for cooling in turbine functions and for house hold

purposes in areas of desert. They can be used for Compressors with some

primary changes involved in their fitting and functioning. They do not affect

the working of the rest of the compressor in any way. Also its Safe and

Environment friendly in their use.

EVAPORATIVE COOLERS:

What is Evaporative Cooling?

An evaporative cooler (also swamp cooler, desert cooler and wet air

cooler) is a device that cools air through the evaporation of water. Evaporative

cooling differs from typical air conditioning systems which use vapour-

compression or absorption refrigeration cycles. Evaporative cooling works by

employing water's large enthalpy of vaporization.

An evaporative cooler produces effective cooling by combining a natural

process - water evaporation - with a simple, reliable air-moving system. Fresh

outside air is pulled through moist pads where it is cooled by evaporation and

circulated through a house or building by a large blower.


Working of Evaporative Cooler:

An evaporative cooler is essentially a large fan with water

front of it. The fan draws warm

outside air through the pads and

blows the now-cooled air

throughout the house.

The pads can be made of

wood shavings - wood from

aspen trees is a traditional choice

- or other materials that absorb

and hold moisture while resisting

mildew. Small distribution lines

supply water to the top of the

pads. Water soaks the pads and,

thanks to gravity, trickles through

them to collect in a sump at the bottom of the cooler. A small re circulating

water pump sends the collected water back to the top of the pads.

Since water is continually lost through evaporation, a float valve

like the one that controls the water in a toilet tank

when the level gets low. Under normal conditions, a swamp cooler can use

between 3 to 15 gallons of water a day.

A large fan draws air through the pads, where evaporation drops

temperature approximately 20 degrees. The fan then blows this cooled air.

Small units can be installed in ventilation, blowing cooled air directly into a

target.

Implementation and Benefits of Evaporative cooler:

Evaporative coolers are rated by the

of air that they deliver to the house. Most models range from 3,000 to 25,000

cfm. Manufacturers recommend providing enough air

40 air changes per hour, depending on climate.

out of an evaporative cooler obviously depends on the temperature and the

humidity of the air going in.

Working of Evaporative Cooler:

An evaporative cooler is essentially a large fan with water-moistened pads in

front of it. The fan draws warm

outside air through the pads and

cooled air

The pads can be made of

wood from

aspen trees is a traditional choice

or other materials that absorb

and hold moisture while resisting

Small distribution lines

supply water to the top of the

pads. Water soaks the pads and,

thanks to gravity, trickles through



Since water is continually lost through evaporation, a float valve

like the one that controls the water in a toilet tank - adds water to the sump


between 3 to 15 gallons of water a day.

A large fan draws air through the pads, where evaporation drops



Implementation and Benefits of Evaporative cooler:

Evaporative coolers are rated by the cubic feet per minute (cfm)


cfm. Manufacturers recommend providing enough air-moving capacity for 20

40 air changes per hour, depending on climate. The temperature of air coming


humidity of the air going in.

moistened pads in



Since water is continually lost through evaporation, a float valve - much

adds water to the sump


A large fan draws air through the pads, where evaporation drops the



cubic feet per minute (cfm)


moving capacity for 20–

The temperature of air coming



The chart shows that an evaporative cooler can deliver comfortable air

under a wide variety of typical summertime temperature and humidity ranges.

In addition to the dropping the temperature of the air, evaporative cooling

offers an additional cooling benefit. The constant movement of the air created

by the blower - the cooling breeze it creates, if you will

to 6 degrees cooler than the actual temperature.





the cooling breeze it creates, if you will - makes the room feel 4

r than the actual temperature.





makes the room feel 4


( * above mentioned air temperature is in Fahrenheit Scale)

An added benefit of evaporative cooling is that it works best in the

hottest time of the day. As the temperature outside increases as the sun

climbs, the humidity normally drops. In the early morning, for example, the

temperature may be 30°C, with a relative humidity of 60 percent. By mid

afternoon, when the temperature has climbed to 40°C, the humidity may well

have dropped to 30 percent

more effectively.

Multi stage Evaporative coolers:

Two stage evaporative coolers have been developed that pre

goes through the moistened pad. The new coolers are reported to be as

effective as air conditioni

same as air conditioning. The price may come down as more such systems are

sold, but for the time being two

Evaporative coolers are now on the market that uses photovolta

panels to create the electricity used to run the blower and the water pump.

For hot areas, the combination of evaporative cooling and solar power are a

perfect match: the afternoon, when the most solar energy is available, is also

the hottest part of the day, when cooling is most needed. And since swamp

coolers use a fraction of the energy of air conditioners, PV cells can provide

enough electricity to run the system effectively.




humidity normally drops. In the early morning, for example, the

temperature may be 30°C, with a relative humidity of 60 percent. By mid


have dropped to 30 percent - conditions that make evaporative cooling work

Multi stage Evaporative coolers:

Two stage evaporative coolers have been developed that pre-cool air before it


effective as air conditioning, but their initial cost is high, approximately the


sold, but for the time being two-stage systems are hard to find.

Evaporative coolers are now on the market that uses photovolta




e day, when cooling is most needed. And since swamp


enough electricity to run the system effectively.




humidity normally drops. In the early morning, for example, the

temperature may be 30°C, with a relative humidity of 60 percent. By mid-


make evaporative cooling work

cool air before it


ng, but their initial cost is high, approximately the


stage systems are hard to find.

Evaporative coolers are now on the market that uses photovoltaic




e day, when cooling is most needed. And since swamp



CHILLER: What is a chiller?

A chiller is a machine that removes heat from a liquid via a vapour

compression or absorption refrigeration cycle

circulated through a heat exchanger

Working of a Chiller.

As airflow passes through the chilled

coils, the air is cooled through an indirect

heat exchange with the coo

then passes through drift eliminator media

and into the turbine. The coils are cold and

therefore condensation is created.

Condensate droplets are directed downward

and collected in pans, then directed out of

the system. Typically, al

eliminated this way, but to ensure air

dryness, mist eliminator panels are in place

to remove any stray condensate droplets. In

the chiller, refrigerant flows through the coil

that cools the chilled water.

The chilled water is pumped through a

piping loop to air handlers in the spaces to be

is a machine that removes heat from a liquid via a vapour

absorption refrigeration cycle. This liquid can then be

heat exchanger to cool air or equipment as required.

As airflow passes through the chilled

coils, the air is cooled through an indirect

heat exchange with the cooling fluid. The air

then passes through drift eliminator media

and into the turbine. The coils are cold and

therefore condensation is created.

Condensate droplets are directed downward

and collected in pans, then directed out of

the system. Typically, all Condensation is

eliminated this way, but to ensure air

dryness, mist eliminator panels are in place

to remove any stray condensate droplets. In

the chiller, refrigerant flows through the coil

that cools the chilled water.

The chilled water is pumped through a

piping loop to air handlers in the spaces to be

is a machine that removes heat from a liquid via a vapour-

. This liquid can then be

to cool air or equipment as required.


cooled, where it absorbs heat from the air that flows over the air handling coil.

The warmed up water then returns through the piping loop back to the chiller,

where the heat it absorbed is released to the refrigerant flowing through the

chillers evaporator.

The chilled water circuit of a typical water chiller system will consist of a

pump, cooling coils, expansion tank, and piping valves and controls, in a closed

loop. The temperature of the chilled water supplied to the loop will depend on

the set point of the chiller. The temperature in the spaces being cooled will be

controlled by thermostats.

Performance of a Chiller.

The factors that affecting the operation of Chiller are total life cycle cost,

the power source, chiller IP rating, chiller cooling capacity, evaporator capacity,

evaporator material, evaporator type, condenser material, condenser capacity,

ambient temperature, motor fan type.

To maintain the chiller its fins and parts should stay clean enough to

function well for many years. Using pre-filters to ensure the cleanliness and

functionality of the coils will maximise its life span. For maximum performance,

the design temperature of the air leaving the cooling system and entering the

turbine is typically no less than 7°C. The ambient air temp and the altitude at

the site are the major factors used in sizing and designing a coil system.

Cooling agents are usually either water or a water/glycol mix, depending on

local ambient conditions.

Comparison between Chillers and Evaporative Coolers:

Evaporative cooler Chiller coils

Advantages:

• Economical operation

• Uncomplicated System

Advantages:

• Can cool the inlet air regardless

of ambient humidity.

• Can be sized for small or large

systems

Disadvantages:

• Not preferred in areas with high

humidity of air.

• Need source of make-up water.

Disadvantages:

• Need source of chilled water

• Cause slightly higher Pressure

difference than an evaporative

cooler does.


CONCLUSION:

• To increase the performance of CC, it can be provided with lighter air

by reducing the humidity content in air, and cooler air by decreasing

the inlet temperature.

• Machines that perform our desired function are Evaporative Coolers

and Chillers. They do mild cooling with little humidity reduction

(reduce air temperature by around 5°C or so and dehumidify by

around 10%). They also use lesser power than any other refrigeration

equipment.

• In more humid conditions, Chiller coils are preferred to Evaporative

coolers.

• Energy Savings comes in a noticeable amount for each method, and

when combined it sums up. Therefore it is best for results when both

the methods are in use simultaneously.

• This project elaborates about Centrifugal Compressor and Optimizing

efficiency ways in a theoretical description and practical methods of

implementation.

This report is Submitted by Sugan Durai Murugan and Suram Srikanth, and is illegal to copy and distribute.

hmil - project report

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