SEMINAR TOPIC IN MECHANICAL ENGINEERING ON FUEL CELLS. SHORT AND BRIEF PRESENTATION ON FUEL CELLS. The presentation consists for preview till conclusion and is meant for minor projects submission by engineering students.
PEMFC (proton exchange membrane)
DMFC (direct methanol)
SOCF (solid oxide)
AFC (alkaline)
PAFC (phosphoric acid)
MCFC (Molten Carbonate)
PEM Fuel Cell
A fuel cell is a battery that produces DC current and voltage
Most fuel cells use hydrogen which burns cleaner compared to hydrocarbon fuels
A fuel cell will keep producing electricity as long as fuel is supplied
The energy efficiency of fuel cells is high when compared to many other energy systems
There is great interest in fuel cells for automotive and electronic applications
There will be employment for technicians particularly in Ohio’s fuel cell industry.
SEMINAR TOPIC IN MECHANICAL ENGINEERING ON FUEL CELLS. SHORT AND BRIEF PRESENTATION ON FUEL CELLS. The presentation consists for preview till conclusion and is meant for minor projects submission by engineering students.
PEMFC (proton exchange membrane)
DMFC (direct methanol)
SOCF (solid oxide)
AFC (alkaline)
PAFC (phosphoric acid)
MCFC (Molten Carbonate)
PEM Fuel Cell
A fuel cell is a battery that produces DC current and voltage
Most fuel cells use hydrogen which burns cleaner compared to hydrocarbon fuels
A fuel cell will keep producing electricity as long as fuel is supplied
The energy efficiency of fuel cells is high when compared to many other energy systems
There is great interest in fuel cells for automotive and electronic applications
There will be employment for technicians particularly in Ohio’s fuel cell industry.
Post-combustion CO2 capture from natural gas combined cycles by solvent supported membranes - presentation by Matteo Romano of Politecnico di Milano at the UKCCSRC Natural Gas CCS Network Meeting at GHGT-12, Austin, Texas, October 2014
Co2 emission rate per MWh of energy generated from coal fired plantsDavid Palmer, EIT
It has been proven that carbon dioxide emissions (greenhouse gases GHGs) absorb energy, slowing or preventing the loss of heat to space. In this way, GHGs act like a blanket, making Earth warmer than it would otherwise be. This process is commonly known as the “greenhouse effect”. How much GHGs are actually emitted from Ontario plants.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Boiler Efficiency Improvement through Analysis of Lossesijsrd.com
Thermal is the main source for power generation in India. The percentage of thermal power generation as compare to other sources is 65 %. The main objective of thermal power plant is to fulfill the energy demands of the market and to achieve these demands; plant requires technical availability with the parts reliability and maintenance strategy. This paper deals with the determination of current operating efficiency of Boiler and calculates major losses for Vindhyachal Super thermal power plant (India) of 210 MW units. Then identify the causes of performance degradation. Also find the major causes of heat losses by Fault Tree Analysis (FTA) and recommends its appropriate strategy to reduce major losses. The aim of performance monitoring is continuous evaluation of degradation i.e. decrease in performance of the steam boiler. These data enable additional information which is helpful in problem identification, improvement of boiler performance and making economic decisions about maintenance schedule.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
ENGINEERING CHEMISTRY: Module 3 [chemical fuels & solar cells]
1. CHEMICAL FUELS AND PHOTOVOLTAIC CELLS
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ENGG.CHEMISTRY [RM] Page 1
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Definition of a chemical fuel: A chemical fuel is a substance, which produces a significant amount of heat
energy and light energy when burnt in air or oxygen.
Classification of chemical fuels:
Chemical fuels are classified as primary and secondary fuels. Fuels, which occur in nature, are called primary fuels.
Fuels, which are derived from primary fuels, are called secondary fuels.
Chemical fuels are further classified as solids, liquids and gases. A complete classification of fuels with examples is
shown in the following Table.
Physical state Primary fuels Secondary fuels
Solid Wood, coal Charcoal, coke
Liquid Petroleum Petrol, diesel, kerosene
Gas Natural Gas LPG, CNG, Water gas, producer gas
Importance of hydrocarbons as fuels: Fossil fuels contain mainly hydrocarbons. These hydrocarbons are important
sources of energy in daily life. Hydrocarbons are used as energy sources in cooking, lighting, automobiles, production of
electricity in thermal power plants etc. These hydrocarbon fuels meet 80% of the world’s energy demand. Thus
hydrocarbons are important sources of energy.
Definition of calorific value of a fuel [Gross calorific value]:It is defined as the amount of heat
liberated when unit quantity (1 kg or 1 m3
) of a fuel is completely burnt in air or oxygen and the products of combustion
are cooled to room temperature.
Definition of net calorific value: It is defined as the amount of heat released when unit quantity of a fuel is
completely burnt in air or oxygen and the products of combustion are let off into the atmosphere.
2. CHEMICAL FUELS AND PHOTOVOLTAIC CELLS
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S. I. unit of calorific value: For solids, calorific value is expressed in J kg-1
(Joules per kg). For gaseous fuels it is
expressed in J m-3
(Joules / m3
).
Determination of calorific value of a solid fuel using Bomb Calorimeter:
Principle: A known mass of the solid sample is burnt in excess oxygen. The surrounding water and the calorimeter
absorb the heat liberated. Thus the heat liberated by the fuel is equal to the heat absorbed by the water and the calorimeter.
Construction: The bomb calorimeter consists of a stainless steel vessel with an airtight lid. This vessel is called bomb.
The bomb has an inlet valve for providing oxygen atmosphere inside the bomb and an electrical ignition coil for starting
of combustion of fuel. The bomb is placed in an insulated copper calorimeter. The calorimeter has a mechanical stirrer for
dissipation of heat and a thermometer for reading the temperature.
Working: A known mass of the solid fuel is placed in a crucible. The crucible is placed inside the bomb. The lid is
closed tightly. The bomb is placed inside a copper calorimeter. A known mass of water is taken in the calorimeter. The
bomb is filled with oxygen at a pressure of 25-30 atm. The temperature t1 in the thermometer is noted.
On passing an electric current through the ignition coil, the fuel gets ignited. The fuel burns liberating heat. The water is
continuously stirred using the stirrer. The maximum temperature attained by the water, t2 , is noted.
Observation and calculations:
b) Calculation of G C V
Gross calorific value (G C V) =
m
tsww 21
kJ kg-1
Where
3. CHEMICAL FUELS AND PHOTOVOLTAIC CELLS
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ENGG.CHEMISTRY [RM] Page 3
MODULE-2MODULE-3
w = w1+ w2
= mass of water in the calorimeter, in kg + water equivalent of the calorimeter, in kg
s = specific heat of water, in kJ kg-1 o
C-1
t = t2-t1 = rise in temperature, in o
C
m = mass of the fuel, in kg
(Note: If the mass of fuel is given in grams, convert that into kg. For example, 0.2 g = 0.2 10-3
kg. If specific heat of
water is given in J kg-1o
C-1
, calorific value will be in J kg-1
. If the specific heat is given in kJ kg-1o
C-1
, then the calorific
value will be in kJ kg-1
.)
(Note: Specific heat of water is the amount of heat energy required to increase the temperature of one kg of water by one
degree C.)
b) Calculation of N C V
NCV = GCV-0.09 % H Latent Heat of steam ……..kJ Kg-1
NCV = GCV-0.09 % H 2454 103
kJ Kg-1
Problem 1. Calculate the calorific value of a sample of coal from the following data:
Mass of Coal = 0.6 g
Mass of water + water equivalent of calorimeter = 2200 g
Specific heat of water = 4.187 kJ kg-1o
C-1
Rise in temperature = 3o
C
Solution:
(Note: In solving the problem, follow the steps given below:
1. Write the given quantities and convert them into appropriate units.
2. Write the equation.
3. Substitute the values.
4. Simplify using calculator if necessary.
5. Write the answer.
6. Write the units.)
Given: m = 0.6 g = 0.6 10-3
kg
w1 + w2 = 2200 g = 2.2 kg
s = 4.187 kJ kg-1o
C-1
t = 3o
C
Gross calorific value =
m
tsww 21
kJ kg-1
= 3
106.0
3187.42.2
= 46057 kJ/kg
4. CHEMICAL FUELS AND PHOTOVOLTAIC CELLS
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Problem 2. A 0.85 g of coal sample (carbon 90 %, H2 5%, and ash 5% ) was subjected to combustion in a bomb
calorimeter. Mass of water taken in the calorimeter was 2000 g and the water equivalent of calorimeter was 600 g.
The rise in temperature was 3.5 o
C. Calculate the gross and net calorific value of the sample. (Given, specific heat
of water = 4.187 kJ kg-1o
C-1
and latent heat of steam = 2454 kJ kg-1
)
Solution: Given m = 0.85 g = 0.85 10-3
kg
% of hydrogen = 5%
w1 = 2000 g = 2 kg
w2= 600 g = 0.6 kg
t = 3.5 o
C
s = 4.187 kJ kg-1o
C-1
L = 2454 kJ kg-1
a) Gross C.V. =
m
tsww 21
=
3
1085.0
5.3187.46.02
= 44825kJ kg-1
b) Calculation of N C V
NCV = GCV-0.09 %H Latent Heat of steam ……..kJ Kg-1
=44825 -0.09 5 2454 =44825 - 1104.3 =43720kJ kg-1
(Note: Latent heat of steam is the amount of heat energy liberated when one kg of steam is converted into one kg liquid
water.)
Problem 3. On burning 0.75g of a solid fuel in a bomb calorimeter the temperature of 2.5kg of water is increased
from 240
C to 280
C the water equivalent of calorimeter and latent heat of steam are 0.485 Kg and 4.2X587
KJ/Kgrespectively , specific heat of water is 4.2KJ/Kg/0
C, H2 2.5%.
Solution: Given
m = 0.75 g = 0.75 10-3
kg
w1+W2 = (2.5+0.485) kg = 2.985 kg
t = t2-t1=28-24=4 o
C
s = 4.2 kJ kg-1o
C-1
L = 2454 kJ kg-1
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MODULE-2MODULE-3
a) Gross C.V.=
m
tsww 21
= KgkJKgJk
X
XX
/66864/
1075.0
2.44985.2
3
b) Calculation of N C V
NCV = GCV-0.09 % H Latent Heat of steam ……..kJ Kg-1
=66864-0.09 2.54.2X587 =66864– 554.715=66309kJ kg
Problem 4. Calculate the gross and net calorific values by data given.
Mass of Coal = 0.7 g = 0.7 10-3
kg
Mass of water = 2.2 kg
Water equivalent of calorimeter = W2 = 0.25 Kg
Raising temperature = 3.2 0
C
Specific heat of water = 4.187 kJ kg-1o
C-1
Latent heat of steam = 580 calories / g [1 calorie = 4.187 kJ]
H2 =2%,
Solution :
m = 0.7 10-3
kg
w1+W2 = 2.45 kg
t = 3.2 o
C
s = 4.187 kJ/kg/o
C
L = 580 calories / g=580 X 4.187kJ /Kg = 2428kJ/Kg
Solution:
Gross C.V. =
m
tsww 21
= KgkJ
X
XX
/44689
107.0
187.42.345.2
3
b) Calculation of N C V
NCV = GCV- 0.09 %H Latent Heat of steam ……..kJ Kg-1
= 46894- 0.09 2580 X4.187 kJ kg-1
=46894-437.122 =46456 kJ kg-1
Problem 5. On burning 0.96g of a solid fuel in bomb calorimeter the temperature of 3500g of H2O increased by
2.70C water equivalent of colorimeter and latent heat of steam are 385 g and 587 cal/g respectively. If the fuel
contains 5% H2 calculate its gross and net calorific value.
Given:
m=0.96g=0.96X10-3
Kg
W1=3500g=3500X10-3
Kg
W2=385g= 385X10-3
Kg
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t=2.70
C
Latent heat =587 cal/g = 587X4.187 kJ/Kg
S= 4.187 kJ/Kg/0
C
H2 =5%,
Gross calorific value =
KgJk
m
tsww
/21
= 3
33
1096.0
7.2187.4)10385103500(
XX
= 45749.5 kJ/Kg
NCV = GCV- 0.09 %H Latent Heat of steam ……..kJ Kg-1
=45749.5- 0.09 5587X 4.187=44643 kJ/kg
Problem 6: On burning 0.85 ×10-
3 kg of a solid fuel in a bomb calorimeter ,the temperature of 2.1 kg wateris raised
from 24O
C to 27.6O
C.the water equivalent of calorimeter and latent heat of steam are 1.1 kg and 2454 kj/kg
respectively. Specific heat of water is 4.187 kJ/kg. if the fuel contains 2% hydrogen ,calculate its gross and net
calorific values.
m = 0.85 X 10-3
kg
W1=2.1Kg
W2 = 1.1 Kg
t1= 24O
C
t2=27.6O
C
s = 4.187kj/Kg
L = 2454Kj/Kg
KgkJ
X
X
KgJ
m
tsww
GCV /56746
1085.0
6.3187.4)1.11.2(
/
)(
3
21
NCV = GCV- 0.09 %H Latent Heat of steam ……..kJ Kg-1
=56746- 0.09 22454 =56746-441.72 =56304kJ kg-1
Problem 7: On burning 0.96 X 10-3
Kg of a solid fuel, in a bomb calorimeter, the temperature of 3.5 Kg of water
was increased by 2.7o
C. Water equivalent of the calorimeter and latent heat of steam are 0.385 Kg 2455 KJ/Kg,
respectively. If the fuel contains 5% hydrogen, calculate its gross and net calorific value.
Solution: Given m = 0.9610-3
kg
% of hydrogen = 5%
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w1 = 3.5 kg
w2 = 0.385 kg
t = 2.7 o
C
s = 4.187 kJ kg-1o
C-1
L = 2455 kJ kg-1
a) Gross C.V. =
m
tsww 21
=
3
1096.0
7.2187.4855.3
= 45749 kJ kg-1
b) Calculation of Net C.V.:
NCV = GCV- 0.09 %H Latent Heat of steam ……..kJ Kg-1
=45749-0.09 52455 =45749-1104.3 =44644.7kJ kg-1
CRACKING
Definition of cracking: Cracking is defined as the process of converting high molecular weight hydrocarbons into
lower molecular weight hydrocarbons to increase the yield of the gasoline.
C14H30 C7H16 + C7H14
Fluidized bed catalytic cracking:
Principle: In fluidized bed catalytic cracking, the powder catalyst is kept agitated by gas streams (cracking fuel) so that
the catalyst can be handled like a fluid system. This also results in a good contact between the catalyst surface and the
reactant.
Construction: A schematic diagram of fluidized bed catalytic cracking method is shown in the following figure.
Optimum conditions:
Feed stock : Heavy oil
Catalyst used: y- type zeolite activated with a rare earth oxide(Al2O3+ SiO2)
Temperature: 450 to 5500
C
Pressur : 1 to atm
Yield: 70 to 80%
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Working: The feed stock vapors are passed
into cracking chamber. The reactants undergo
cracking in the presence of catalyst. The
products are passed to a fractionating
column.Spent catalyst from the cracking
chamber is continuously transported into the
regeneration chamber through an air stream.
The carbon deposited on catalyst particles is
burnt off in regeneration Chamber. The
regenerated catalyst is transported back into
the cracking chamber together with feed stock.
REFORMATION OF PETROL
Definition of reformation of petrol: Conversion of straight chain hydrocarbons in petrol into branched chain, cyclic and
aromatic hydrocarbons, resulting in up gradation of quality of the petrol is known as reformation.
How reformation improves the quality of petrol?
The octane number for straight chain hydrocarbons is low. For branched chain, cyclic and aromatic hydrocarbons, the
octane number is high. Thus reformation converts the low octane number petrol into high octane number petrol.
Reformation reaction conditions:
Reactant (feed stock) : Gasoline obtained by fractionation of petroleum + H2
Catalyst: Platinum supported on alumina (Pt / Al2O3 )
Temperature: about 500 o
C
Pressure: 15-50 atm
Reformation reactions:
The main reformation reactions are:1) Isomerization, 2) Dehydrogenation and 3) Cyclization and dehydrogenation.
1) Isomerization:
Example: n – Heptane 5 - Methyl hexane
H3C CH2 CH2 CH2 CH2 CH2 CH3
n-Heptane
H3C CH CH2 CH2 CH2
CH3
CH3
2-Methyl-hexane
2) Dehydrogenation:
Example: Cyclo hexane Benzene + Hydrogen
9. CHEMICAL FUELS AND PHOTOVOLTAIC CELLS
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H2C
H2C
C
H2
CH2
CH2
H2
C
+ 3H2
3) Cyclization and dehydrogenation
H2C
H2C
C
H2
CH2
CH2
H2
C
H3C
H2
C
H2
C
H2
C
H2
C CH3
-H2 -3H2
Synthetic petrol
Synthesis of petrol by Fischer-Tropsch process:
Franz Fisher- Hans Tropsch showed that carbon monoxide and hydrogen in the presence of catalyst at 180-250o
C form a
mixture of aliphatic hydrocarbons ranging from methane to wax. The natures of the products formed however depend on
the temperature, pressure and catalyst used.
Process: In this process a mixture of [CO+H2] is preheated and passed through a compressor. Then the mixture is send to
catalyst reactor contains a iron based or cobalt based catalyst at 200-3000
C, produces a mixture of hydrocarbons. The
petroleum (Mixture of hydrocarbons) so formed is next fractionated to yield gasoline, kerosene, heavy oil and paraffin
wax.
Diagram :
10. CHEMICAL FUELS AND PHOTOVOLTAIC CELLS
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n CO + 2nH2 CnH2n + nH2O
Unsaturated hydrocarbons
n CO + (2n + 1)H2 CnH2n + 2 + nH2O
Saturated hydrocarbons
Knocking in petrol engine:
Definition of knocking: Knocking may be defined as the production of a shock wave in an IC engine as a result of an
explosive combustion of fuel-air mixture, leading to a rattling sound.
FOUR STROKE INTERNAL COMBUSTION ENGINE (CAR ENGINE / PETROL ENGINE):
1st Stroke INTAKE: piston moves down, air + diesel fuel mixture drawn in
2nd Stroke COMPRESSION: piston moves up, air + fuel mixture compressed then ignited by sparking plug
3rd Stroke POWER: piston pushed down by exploding air + fuel mixture
4th Stroke EXHAUST: piston moves up, spent gases pushed out through exhaust
Compression ratio =
𝑎 ℎ ℎ 𝑖
𝑎 ℎ ℎ 𝑖
Mechanism of knocking in chemical terms:
A. Under normal conditions there is smooth oxidation of the fuel. It involves following reaction
Oxygen combines with hydrocarbon molecule (for example, ethane) forming carbon dioxide and water
C2H6 + 31/2O2 2CO2 + 3H2O
B. Under knocking conditions, the rate of combustion is very high. It involves following steps.
1. Oxygen combines with hydrocarbon molecule forming peroxides.
H3C CH3 + O2 H3C O O CH3
Ethane Ethane peroxide (unstable)
11. CHEMICAL FUELS AND PHOTOVOLTAIC CELLS
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2. The peroxides decompose readily to give a number of gaseous products. For example,
H3C O O CH3
Ethane peroxide
CH3 CHO + H2O
Acetaldehyde
CH3 CHO
Acetaldehyde
+ 11/2O2 HCHO + CO2 + H2O
Formaldehyde
Formaldehyde
HCHO + O2 H2O + CO2
Formation of peroxide, number of gaseous product and rapid increase of pressure results in explosive combustion &
knocking in IC engine .
Antiknocking agent for Petrol engine: Antiknocking agent is a chemical substance added to petrol to improve the
Antiknocking property of the petrol. For example, tetra ethyl lead (TEL). Addition of TEL to petrol increases the octane
number of petrol. TEL is normally used along with ethylene dibromide or ethylene dichloride. [Formula of tetra ethyl
lead = (C2H5)4Pb ]
Unleaded petrol: Unleaded petrol is the petrol where tetra ethyl lead (TEL) is not used as an antiknocking agent.
Addition of TEL to petrol leads to release of PbBr2 and PbCl2 into the atmosphere through automobile exhaust. This
results in air pollution. To prevent air pollution, unleaded petrol is preferred.
In unleaded petrol, methyl-t-butyl ether (MTBE) and ethyl-t-butyl ether (ETBE) are used as antiknocking agents.
Definition of octane number: The octane number of a gasoline (petrol) is the percentage volume of iso-octane in a
mixture of iso-octane and n-heptane, which has the same knocking property as the gasoline being tested.
CH3 C
CH3
CH3
CH2 CH
CH3
CH3
2,2,4 Tri Methyl Pentane
H3C CH2 CH2 CH2 CH2 CH2 CH3
n - Heptane
Knocking in diesel engine:
In diesel engine there is no spark plug.
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The air is passed into the cylinder and it is compressed by the piston till it attains
ignition temperature of the fuel .As soon as the fuel is injected in to the cylinder, it
absorbs heat from the heated air and burns on attaining ignition temperature
spontaneously.
Ignition delay is the time lag between the start of the fuel injected and its ignition.
Straight chain hydrocarbon has shorter ignition delay whereas branched and
aromatic hydrocarbon has longer ignition delay.
Ignition delay causes accumulation of more hydrocarbons and results in explosive
combustion is called as ‘diesel knocking’.
Antiknocking agent for diesel engine: Antiknocking agent is a chemical substance added to diesel to improve the
Antiknocking property of the diesel.
Ex. Alkyl nitrates and Amyl nitrates
Cetane number: The cetane number of a diesel fuel is the percentage by volume of n-cetane in a mixture of n-cetane
and -methyl naphthalene which has the same knocking characteristic as the diesel being tested.
H3C (CH2)14 CH3
n-cetane
= C16H34 = Hexadecane C10H7 CH3
Methyl naphthalene
POWER ALCOHOL
Definition of power alcohol: When ethyl alcohol is used as an additive to motor fuel(petrol) to act as a fuel for
internal combustion engines, it is called power alcohol.
The importance’s of power alcohol as fuel are:
(Characteristics of alcohol-blended petrol are: )
1. The power output is good.
2. Addition of alcohol reduces the emission of carbon monoxide and volatile organic compounds in to the atmosphere.
3. Alcohol improves the antiknocking property of the fuel.
4. Petrol-alcohol mixture has the same lubrication as the pure petrol has.
5. Since ethanol is produced from agricultural products, it can be a sustainable fuel.
6. Ethanol is biodegradable
Biodiesel: Biodiesel is obtained by the transesterification of the vegetable oil or animal fat or blue green algae and
used as a fuel in the internal combustion engine.
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Production:
Biodiesel is produced by the trans-esterification of the
vegetable oil or animal fat or blue green algae with
methanol and NaOH catalyst at 60 O
C.
CH2OCOR1
CHOCOR2
CH2OCOR3
+ 3CH3OH
NaOH
60o
C
CH3OCOR1
+
CH3OCOR2
+
CH3OCOR3
+
CH2OH
CHOH
CH2OH
Biodiesel GlycerolTriglyceride oil
NOTE: Soap formation is avoided by esterification of
free fatty acid in presence of acid catalyst fallowed by
trans-esterification
Advantages:
1. Biodiesel is a renewable source of energy.
2. It is an alternative fuel for fossil fuels.
3. It refers to a vegetable oil or animal fat based diesel.(Green fuel).
4. It is biodegradable.
5. It has a high flash point and low ignition point than diesel.
6. Addition of alcohol reduces the emission of carbon monoxide and volatile organic compounds in to the
atmosphere.
7. It is nontoxic.
Solar Energy
Direct solar energy: Direct solar energy involves only one step transformation into a usable form.
Examples: Solar water heater, Solar cooker, Photovoltaic cells.
Indirect solar energy: Indirect solar energy involves more than one transformation to reach a usable
form.
Examples: Photosynthesis, Ocean thermal energy
Photovoltaic Cells:
Photovoltaic cells are semiconductor device which convert solar energy into electrical energy.
(Photovoltaic cell is based on the principle of photoelectric effect).
Construction & Working of Photovoltaic Cell:
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A typical silicon photovoltaic cell consists of p-n junction made of silicon.
It consists of two electrical contacts, one of which is in the form of metallic grid and allows light
to fall on the semiconductor between the grid lines.
The cell’s other electrical contact is formed by a metallic layer on the back of the solar cell.
An antireflective layer avoids the reflection of light.
When light radiation falls on the p-n junction diode, electron-hole pairs are generated by the
absorption of the radiation.
𝐸 = ℎ𝜗 = ℎ
𝜆
The electrons are made to move across the external circuit.
Thus photoelectric current is produced and available for use.
Advantages:
Fuel source is vast and essentially infinite.
No emissions, no combustion or radioactive residues for disposal. Does not contribute to global
change or pollution.
Low operating cost (no fuel).
No moving parts and so no wear and tear.
High reliability in modules.
Can be integrated into new or existing building structures.
High public acceptance and excellent record.
Disadvantages:
Sun light is a diffuse, i.c., it is relatively low density energy.
High installation cost.
Poor reliability of auxiliary elements including storage.
Energy can be produced only during the day time.
Metallic grid
Layer of silver
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Importance of Photoelectric cell:
Photovoltaic cell provides enormous amount of energy from sun which is unlimited,
inexhaustible and renewable.
Photovoltaic cells can serve for both off grid and on grid application.
Photovoltaic cell produces no pollution so it is environment friendly.
Photovoltaic cell energy conversion is highly modular. This is important with respect to the
development of electricity supply systems in many rural and remote areas, where grid
extension is economically not feasible.
It provides power for space craft and satellite.
Photovoltaic can be used as roof integrated systems, providing power and also serving as
optical shading elements for the space below and preventing overheating in the summer.
Developments in the field of Photovoltaic cells will boost the semiconductor industry and
storage battery industries.
PHOTOVOLTAIC MODULE , PANEL & ARRAY
Photovoltaic module: A number of Photovoltaic cells electrically connected to each other and mounted
in a support structure or frame is called photovoltaic module.(0.5-0.6V)
Photovoltaic panel: Multiple modules electrically connected to each other and mounted in a support
structure or frame is called photovoltaic panel.(27-36 cells, 12-18V)
Photovoltaic arrays: Photovoltaic array is the complete power generating unit, It consist of number of
photovoltaic panels, electrically connected to each other and mounted in a frame.
Physical properties of silicon relative to photovoltaics:
Physical properties of silicon are as follow:
Silicon is a semiconductor with band gap of 1.2eV at 25o
C.
At atmospheric pressure, silicon crystallizes to diamond cube like structure.
Panel
Array
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Silicon contracts when melted and expand when solidify.
High refractive index limits the optical applications of silicon.
The absorption and transmission properties in the 0.4-0.5 µm wavelength spectra are important in
the performance of photovoltaic cells.
Chemical properties relevant to photovoltaics:
Silicon is stable in the tetravalent and has a strong affinity for oxygen, forming stable oxides and
silicates.
Silicon and carbon form a strong Si-C bond and stable products.
Silicon forms hydrides, and monosilane (SiH4) is key chemical compound for the production of
amorphous silicon and the purification of silicon to semiconductor grad.
Silicon forms trichlorosilane and tetrachlorosilane with chlorine, which are the intermediates and
the by-products of the purification process in metallurgical grade silicon to semiconductor grade.
Production of solar grade silicon:
Solar grade silicon has impurities in the ppb level is required for polysilicon used in semiconductor
industry. It can be prepared by using two methods.
The Union Carbide process:
This process involves the following steps:
STEP – 1: The hydrogenation of tetrachlorosilane through a bed of metallurgical silicon is carried out in
a fluidized bed reactor
Si + 4HCl SiCl4+2H2 at 3000
C
SiCl4+H2 HSiCl3+HCl at 10000
C
STEP 2: The trichlorosilane is separated by distillation while the unreacted tetrachlorosilane is recycled
back to the hydrogenation reactor.
The purified trichlorosilane is passed through a fixed bed column filled with quaternary ammonium ion
exchange resin acting as catalyst. Trichlorosilane gets converted into dichlorosilane.
2SiHCl3 SiH2Cl2 + SiCl4
STEP 3: The products are separated by distillation, tetrachlorosilane is recycled to the hydrogen reactor
and dichlorosilane is passed through a second fixed bed column filled with quaternary ammonium ion
exchange resin. Dichlorosilane is converted into silane.
3SiH2Cl2 SiH4 + 2SiHCl3
STEP 4 : The above products are separated by distillation and trichlorosilane is recycled to the first bed
column. Silane is further purified by distillation and then pyrolized to produce polysilicon onto heated
silicon seed rods mounted in a metal bell-jar reactor
SiH4 2H2 + Si
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Purification of Silicon by Zone refining Process
Zone refining method is used to get ultra-pure silicon..This process is used where the impurities are
soluble in molten state. When Si rod is melted, impurities tend to concentrate in the molten.
Process:
The impure silicon rod surrounded by RF coil is clamped to vertical zone refiner and it is placed in an
inert argon atmosphere. The silicon rod is heated near to its melting point using RF coil, when the RF
coil is moved slowly from top to bottom ,the dissolved impurities in silicon will also moves along with
the coil [since impurities are more soluble in its molten state] by leaving pure silicon at the upper portion
.The rod is subjected for several zone process to get ultra-pure silicon.
Doping of Silicon:
It is the method of addition of impurity atom to a pure semiconductor to get desired extrinsic (p or n)
semiconductors.
In the preparation of solar grade silicon, impure silicon is converted into vapors this vapors is condensed
on the silicon rod. The vapor of doping material is passed in to the chamber, doping can be accompanied
by simultaneous depositing a dopant with the semiconductor material.
Diffusion Technique:
It is a process of diffusing the impurity atoms into a silicon wafer by heating the thin wafer just below its
melting point in an atmosphere of impurity.
Doping of Silicon by Diffusion Technique:
In this technique, a region of a semiconductor material is incorporated with dopant atoms by the different
impurity atom into the crystal of the material without actually melting it. By this technique the extent of
impurity penetration can be controlled to a very small thickness of the material. For example, a n-type
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silicon can be obtained by heating a silicon wafer below its melting point in an atmosphere of n-type
impurity such as Phosphorus. The impurity atoms condense on the surface of the wafer diffuse into the
crystal. P-type silicon can be obtained by heating a silicon wafer below its melting point in an
atmosphere of P-type impurity such as Boran. The extent of diffusion is regulating by temperature and
concentration of the impurity atom.
Si + PH3
N-Dopped silicon
Diffusion
Si + BH3 B2H6 P-Dopped silicon
Questions :
1. What is chemical fuel ? write a note on classification of fuel
2. Explain the determination of calorific value of a solid or a liquid fuel using bomb calorimeter
3. A 0.85 g of coal sample (carbon 90 %, H2 5%, and ash 5% ) was subjected to combustion in a
bomb calorimeter. Mass of water taken in the calorimeter was 2000 g and the water equivalent of
calorimeter was 600 g. The rise in temperature was 3.5 o
C. Calculate the gross and net calorific
value of the sample. (Given, specific heat of water = 4.187 kJ kg-1o
C-1
and latent heat of steam =
2454 kJ kg-1
)
4. Define the terms : gross calorific value & net calorific value.
5. What is cracking ?Explain the process of cracking using fluidized bed catalytin cracking (FCC)
6. What is reformation? Give any three reaction
7. What is knocking in IC engine? Explain the mechanism of knocking in chemical terms.
8. Explain the following terms : a. octane number b. cetane number c. antiknocking agents
9. Explain the following terms : a. Power alcohol b. biodiesel
10. What is solar cell? Explain the construction & working of PV cell
11. Explain the production of Si by union carbide process
12. Explain photovoltaic module, panel & array
13. Explain the purification os Si by zone refining process
14. What is doping? Explain doping of Si by diffusion technique.