This document provides an introduction to gaseous fuels and their sources. It discusses the objectives of the course which are to describe industrial fuels, combustion phenomena, and fuel processing. It then defines gaseous fuels and lists various sources including methane from coal beds/mines, gobar gas from fermentation of biodegradable waste, and coal gas from coal gasification. The document further discusses gas heating values in terms of calorific value and Wobbe index, and provides more details on the production and composition of methane from coal beds, gobar gas, and coal gas from gasification.

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Fuel and Energy
Dr Zakir Khan
Department of Chemical Engineering
CUI Lahore Campus, Lahore
Introduction to Gaseous Fuels and their
Sources

2. 2
Objectives
Course Learning Outcomes (CLOs)
• CLO-1 Describe the industrial fuels, combustion phenomena and fuel processing
• CLO-2 Explain the industrial combustion system and renewable and alternative
energy sources
• CLO-3 Demonstrate the knowledge of combustion through calculations
 Introduction to gaseous fuels
 Gas heating values
 Sources of gaseous fuels
• Methane from coal bed/mines
• Gobar gas (Dung gas)
• Coal gas from Coal gasification
Objectives and Related CLOs

3. Gaseous fuel
• Fuel which are burnt in gaseous state in the presence of air or oxygen (pure) to
give heat utilization in homes and industry.
Sources
• Methane from coal bed/mines (Coal mines)
• Dung gas (Gobar gas) (Fermentation of biodegradable)
• Coal/biomass gas from gasification (gasification at atmosphere pressure)
• Gas from underground coal gasification (underground gasification)
• Sewage gas (Gas produced by sewage disposal through anaerobic decomposition)
• Liquified petroleum gas (LPG) (Mixture of propane (80-90 %) and Butane (10-20 %) extracted
from oil well)
• Refinery gas (produced during distillation of crude oil or treatment of oil products (e.g.
cracking) in refineries contains H2, CH4 and C2H6)

4. Gaseous fuel
Sources (continue……….)
• Producer gas (Mixture of CO and N2 produces in a furnace by blowing air or mixture of
air/steam in a furnace through coal/coke).
• Blast furnace gas (Generated in Blast furnace when the iron ore is reduced with coke to
metallic iron)
• Water gas (Reaction of superheated steam with bed of hot coke/coal producing CO and H2
mainly)
• Coke oven gas (is produced during the manufacture of metallurgical coke by heating
bituminous coal)
• Oil gas from oil gasification process ( Gasification of light/middle distillate and heavy oils (low
CH ratio) from refinery to produce synthesis gas for Ammonia production to used in
Fertilizers)
• Hydrogen and Acetylene

5. Gas fuel heating values
What is Calorific value (CV) or Heating value
The heat produced by a fuel for its complete combustion
Wobbe Index=CV/(specific gravity)0.5
Gas group Wobbe index (CV in kcal/Nm3
1 Rich fuel gas (>4000 kcal/Nm3)
2
3 7650+380
4 6970+285
5 6400+285
6 5870+240
7 5340+285
Lean fuel gas
(<1500 kcal/Nm3)
• Gross heating values or High
heating values
(With water heating values
In exhaust gas)
• Net heating values or lower
heating values
(without water heating values)
This index is helpful in comparing energy generation from
different fuel gases while using a burner. When the Wobbe
index for two fuel gases is identical or very close (less than 5%),
then for a specified gas pressure and burner valves settings the
energy generation would be nearly identical.

6. Methane from coal bed/mines
• Methane is formed and adsorbed on the surface of coal during
“coalification process”
[CH4=93-99%], C2H6=0-3%, CO2=0-4%, N2=2-6%]
• Methane is desorbed during coal
mining and extremely danger if
not properly handled
Most of the coal we use
now was formed about
300 million years ago. As
plants and trees died,
their remains sank to
the bottom of the
swampy areas, making
layers and layers of
plant material and
eventually forming a
soggy, thick material
called coal (PEAT).

7. Gobar gas (Dung gas)
Temperature 30-40 ℃
Methane rich gas
Fermentation
The chemical breakdown of a substance by bacteria, yeasts, or other microorganisms and the giving off of heat.

8. • To convert solid carbonaceous fuel (biomass and coal etc.) into a
gaseous mixture i.e. H2, CO CO2 and CH4.
8
What is Gasification
Coal
Gasification Steps
Solid
Liquid
Coal gas from coal gasification
Difference between Combustion and
Gasification???

9. 9
Reactors for Coal Gasification