This presentation summarizes the topic of boilers and steam systems. It includes definitions of key boiler types such as water tube and fire tube boilers. It also classifies different types of steam based on pressure and water content. The major constructional parts of boilers are outlined as well as auxiliary equipment. Combustion processes and burner management steps such as purging are also summarized.

1. Welcome
TO
My Presentation

2. Name: Sajal Mandol
ID:20131207038
Year: 4rd
Semester: 2nd
Session: 2013-2014
Department: Applied
Chemistry and Chemical
Engineering
Course Title: In-Plant training (TICI)
Course Code: ACCE 458
Date: 20.04.2018
Bangabandhu Sheikh Mujibur Rahman Science and
Technology University, Gopalganj
TOPIC- Boiler and Steam System

3. Boiler:
A boiler is closed vessel in which water under pressure is transformed
into steam by the application of heat.
CLASSIFICATION OF BOILER:
Based on construction:
A) Water tube boiler: Here water circulates through the tube, which is
surrounded by flame and hot gases. Generally high-pressure boilers
are of water tube design.
B) Fire tube boiler: Here the hot products of combustion of fuel (flame
or hot gases) pass through the tube, which are surrounded by water.
Based on the application of heat:
A) Direct fire boiler: e. g. Water tube boiler, Fire tube boiler.
B) Indirect fire boiler: e. g. Waste heat boiler.

4. Based on- the method of circulation of water:
A) Natural circulation boiler: Boiler water circulates naturally (by
density difference).
B) Forced circulation boiler: Boiler water is circulated by the action of a
pump.
Based pressure on steam generation:
A) Low pressure steam boiler (< 20 bar).
B) Medium pressure steam boiler (20 to 80 bar).
C) High pressure boiler (< 80 bar)

5. Based on fuel charge in the furnace:
a)Solid fuels: Wood, Coal, Peat, Charcoal, Bagasse, cokes etc.
b)Liquid Fuels: Alcohol, Petroleum oil, Furnace oil, Tar, etc.
c) Gaseous Fuels: Natural gas, Coal gas, Producer gas, etc.
d)Combined fuels: Oil & gas.
Advantages of water tube boiler over fire tube boiler:
It can produce higher pressure steam than that of fire tube boiler.
Steam generation is rapid than fire tube boiler.
For a given power it occupies a smaller area than a fire tube boiler.
It can be constructed to work at high pressure without excessive
thickness of metal.
Heating surface area of water tube boiler is greater than that of fire
tube boiler.

6. Steam system:
Water vapor or water in its gaseous state is known as steam. When
heat energy is transferred to water, its enthalpy and physical state
change (liquid to vapor). The vapor thus formed is known as steam. As
heating takes place the temperature of water rises and generally its
density decreases. The temperature at which boiling and evaporation
occurs is depended on the following-
- The purity of water
- Absolute pressure exerted
Sensible heat:When a quantity of heat applied to a substance is
consumed in raising the substance’s temperature, the heat is called
Sensible heat.
Latent heat : When a substance is heated and its state is changed such
as evaporation or melting by the heat applied under constant
temperature that heat is called latent heat.
The sum of sensible heat and latent heat is called Total heat.

7. Classification of steam:
Steam may be classified into two categories:
1.Based on water content
a)Saturated steam.
b) Superheated steam.
2. Based on pressure:
a)Low pressure steam.
b)Medium pressure steam.
c)High pressure.

8. So 06 kinds of steam can be used in industry
- Low pressure saturated
- Low pressure Superheated
- Medium pressure saturated
- Medium pressure Superheated
- High pressure saturated
- High pressure Superheated.
Quality of steam:
The dry steam per pound of wet steam is the quality of steam.It may be
expressed either as a percentage or as a decimal. e.g. If the steam is
fully dry then the quality of steam is said to be 100%. If the steam
contains 2% moisture, then the quality of that steam will be (100-
2)=98%.

9. Uses of steam:
i. Power generation
ii. Steam engines or Steam Turbines
iii. Heating
iv. Heat Exchangers: Heaters, Evaporators, Re-boilers etc.
v. Room heater/ Radiator
vi. Utilization in process industries such as Ammonia manufacturing vii.
Sizing and bleaching in textile industries.

10. CONSTRUCTION SYSTEM OF NATURAL
CIRCULATION TYPE BOILER
The constituents of a boiler system may be classified as follows:
i. Major constructional parts
ii. Auxiliary equipment
iii. Mountings
iv. Measuring and control Instrument
v. Electrical equipment vi. Piping

12. Major constructional parts of boiler:
A boiler consists of the following major constructional parts:
i. Boiler shell
ii. Furnace / Combustion chamber
iii. Burner
iv. Steam drum & Water drum/mud drum
v. Down comer & Riser
Auxiliary equipment:
i. Deaerator
ii. Feed water pump
iii. Feed water heater/economizer & Air heater
iv. Super heater & Desuperheater
v. IDF (Induced draft fan)
vi. FDF (forced draft fan)
vii. Stack
Mounting:
i. Water level indicator
ii. Pressure gage
iii. Safety valve
iv. Steam supply valve
v. Blow-down valve

13. Combustion:
Combustion is a chemical reaction involving the combination of fuel and oxygen to
produce heat and combustion products. Boiler requires fuel to produce steam,
which may be in the form of gas, liquid and solid. Fossil fuel, utilized for the
generation of steam is generally burned directly in the furnace of boiler. The
convenient source of oxygen is that which forms almost 21% of atmospheric air.
Fuel has a definite intrinsic heat content, which is released by combustion.
Complete combustion occurs when the fuel is fully oxidized and all the energy
released. Incomplete combustion may result from
-Insufficient oxygen
-Poor mixing of fuel and oxygen
-A temperature too low to support combustion

14. BURNER MANAGEMENT
Steps of Burner management:
- Furnace purge
- Burner startup
- Burner trip
Purging:
The removal of exhaust gases or other unwanted gaseous substances
before charging the fuel and ignition by rinsing the boiler with Nitrogen
gas is called Purging.