L. D. COLLEGE OF ENGINEERING

RUBBER TECHNOLOGY

Sub:- THERMODYNAMICS OF ELASTOMERS & POLYMERS

Introduction

The Formation of Fuel

Solar energy is converted to chemical energy through photo-synthesis in plants.

Energy produced by burning wood or fossil fuels

Fossil fuels: coal, oil and natural gas

=>) We know that, in most of the world today, wood is not the main source of fuel. We generally use natural gas or oil in our homes, and we mainly use oil and coal to heat the water to produce the steam to drive the turbines for our huge power generation systems. Coal, oil, and natural gas are often referred to as fossil fuels.

Types of Fuel

Usage

• Used extensively in industrial applications

Examples

• Furnace oil

• Light diesel oil

• Petrol

• Kerosene

• Ethanol

• LSHS (low sulphur heavy stock)

Liquid Fuels

Types of Fuel

Liquid Fuels

Density

• Ratio of the fuel’s mass to its volume at 15 oC,

• kg/m3

• Useful for determining fuel quantity and quality

Types of Fuel

Sulphur content

• Depends on source of crude oil and less on the

refining process

• Furnace oil: 2-4 % sulphur

• Sulphuric acid causes corrosion

Ash content

• Inorganic material in fuel

• Typically 0.03 - 0.07%

• Corrosion of burner tips and damage to materials

/equipments at high temperatures

Liquid Fuels

Types of Fuel

Storage of fuels

• Store in cylindrical tanks above or below the ground

• Recommended storage: >10 days of normal

consumption

• Cleaning at regular intervals

Liquid Fuels

Types of Fuel

Solid Fuels

Coal classification

• Anthracite: hard and geologically the oldest

• Bituminous

• Lignite: soft coal and the youngest

• Further classification: semi- anthracite, semi-

bituminous, and sub-bituminous

Types of Fuel

Solid Fuels

Physical properties

• Heating or calorific value (GCV)

• Moisture content

• Volatile matter

• Ash

Chemical properties

• Chemical constituents: carbon, hydrogen, oxygen,

sulphur

Types of Fuel

Solid Fuels (Physical properties)

Ash

• Impurity that will not burn (5-40%)

• Important for design of furnace

• Ash = residue after combustion

Fixed carbon

• Fixed carbon = 100 – (moisture + volatile matter + ash)

• Carbon + hydrogen, oxygen, sulphur, nitrogen

residues

• Heat generator during combustion

Types of Fuel

Solid Fuels (Chemical Properties)

Storage, Handling & Preparation

• Storage to minimize carpet loss and loss due

to spontaneous combustion

• Reduce carpet loss: a) a hard surface b)

standard concrete/brick storage bays

• Coal preparation before use is important for

good combustion

Types of Fuel

Gaseous Fuels

Advantages of gaseous fuels

• Least amount of handling

• Simplest burners systems

• Burner systems require least maintenance

• Environmental benefits: lowest GHG and other

emissions

Types of Fuel

Gaseous Fuels

Natural gas

• Methane: 95%

• Remains 5%: ethane, propane, butane, pentane,

nitrogen, carbon dioxide, other gases

• High calorific value fuel

• Does not require storage facilities

• No sulphur

• Mixes readily with air without producing smoke or

soot

Types of Fuel

Gaseous Fuels

Liquefied Petroleum Gas (LPG)

• Propane, butane and unsaturated, lighter C2

and heavier C5 fractions

• Hydrocarbons are gaseous at atmospheric

pressure but can be condensed to liquid state

• LPG vapour is denser than air: leaking gases

can flow long distances from the source

Combustion Calculation

There are mainly three types of measuring calorific value of fuel by several technology as per below;

Bomb calorimeter

Junker’s gas calorimeter

Boy’s gas calorimeter

Performance Evaluation

• Combustion: rapid oxidation of a fuel

• Complete combustion: total oxidation of fuel (adequate

supply of oxygen needed)

• Air: 20.9% oxygen, 79% nitrogen and other

• Nitrogen: (a) reduces the combustion efficiency (b) forms

NOx at high temperatures

• Carbon forms (a) CO2 (b) CO resulting in less heat

production

Principles of Combustion

Performance Evaluation

Stochiometric calculation of air

required

Stochiometric air needed for combustion of furnace oil

Theoretical CO2 content in the flue gases

Actual CO2 content and % excess air

Constituents of flue gas with excess air

Theoretical CO2 and O2 in dry flue gas by volume