This document discusses different types of fuel gases, including their composition, production methods, and uses. It covers producer gas, water gas, coke oven gas, natural gas, and LPG. Producer gas is made from coal or coke with air and steam. Water gas involves heating carbon with air and producing gas through reactions with steam. Coke oven gas is a byproduct of coking coal to produce coke. Natural gas and LPG are extracted from natural gas wells and oil refineries. The key engineering challenges involve designing reactors and purification processes to efficiently produce and treat these various fuel gases.

1. FUEL AND
INDUSTRIAL GASES

2. FUEL GASES
Fuel gas is any one of a number of fuels that
under ordinary conditions are gaseous. Many
fuel gases are composed of hydrocarbons (such
as methane or propane), hydrogen, carbon
monoxide, or mixtures thereof. Such gases are
sources of potential heat energy or light energy
that can be readily transmitted and distributed
through pipes from the point of origin directly
to the place of consumption

3. CLASSIFICATION OF
FUEL GAS
 Producer gas
 Water gas
 Coke oven gas
 Carbureted or oil gas
 Natural gas and LPG

4. Chemical reactions:
C(s)+O2(g) (excess air) CO2(g)
2C(s)+o2(g) 2CO(g)
C(s)+CO2(g) 2CO (g)
C(s)+H2O(l) CO(g)+H2(g)
CO(g)+H2O(l) CO2(g)+H2(g)

5. Methods of Production
 PRODUCER GAS:
 Raw materials-
 Coal or blast furnace coke
 Air
 Quantitative requirements
 Basis: 100 Nm3 of producer gas
 Coke 20-25 Kg or coal 25-30 Kg
 Steam 8-10Kg
 Air 60-80 Nm3
 Plant capacities:25000-250000 cubic metres /day

6. Composition: CO ,N2 ,H2 with steam
Principal use : Steel industry heating requirements
(heat treat , coke ovens)
Process description:
Steam and air mixture injected in bottom of a
water cooled jacket of steel furnace
equipped with a rotating grate to remove fusible ash.
Solid fuel is added from hopper
valve on top a furnace. Producer gas is cooled by
passing through a waste heat boiler.

7. Major engineering problems:
 a) Design of suitable gas producer furnace to :
 keep uniform fuel surface
 Provide adequate gas-fuel contact time at high
temperature
 Avoid clinkering and provide for proper fused ash
removal
 b) Addition of correct steam quantities to supply net
heat of reaction near zero on a
 continuous once- through process

8. MANUFACTURE OF PRODUCER GAS

9. WATER GAS
 Composition : CO ,H2
 Principal use : Heating ,chemical synthesis
 Raw materials:
Bituminous, anthracite coal , or coke
 Quantitative requirements
 Basis: 100 cu m of water gas from C
C as coke 55kg
or C as coal 58 kg
Air 220 Nm3
Steam 80 kg
 Plant capacities : 250000-1500000 Nm3 /day

10. Process description:
Regenerative process- older process
consisting of two reactors one operates on
blow period which heats carbon by reaction
2(a) , the other on a run period where
endothermic reaction 2(d) occurs. The cycle
of 4-6 minutes is divided as
Blow or heat up - 35%
Up run - 30%
Down run – 33%
Short purge up run - 2%

11.  Reactors or generators or steel with refractory
lining .If higher BTU gas is required an additional
high temperature carburetor section is required for
pyrolyzing oil spray and mixing .
 Continuous process – newer process ,based on
low purity grade oxygen. The correct ratio of steam
, oxygen and coal is added to the reactor which
yields approximately zero heat release, ash content
greater than 30%

12. Major engineering problems:
a) Designing suitable ash removal system for
various grades of coal in continuous
processing.
b) Optimizing cycle for regenerative process

13. MANUFACTURE OF WATER GAS

14. Principal use COKE OVEN GAS
 Composition : H2 ,CH4 ,CO
 : Heating , Chemical synthesis
 Process description :
Upgraded coal for coking purposes is fed to a by-
product coke oven which uses producer gas for
heating the batch chamber to 1000 0C for 12-20
hours. Gas is removed continuously and put
through a series of purification steps.

15. If NH3 synthesis gas is required , further
purification including scrubbing with alkali to
remove CO2 ,liquefaction to remove light
hydro-carbons and finally scrubbing with liquid
N2 to take out CO . The N2 for scrubbing and
make up is obtained from a liquid air
fractionation plant . The oxygen being used to
purify pig-iron and make high grade steel by the
Linz and Donowitz process.

16.  Major engineering problems :
 Obtaining suitable grades of coking coal in
India . Washing , pre-roasting and solvent
extraction are some of the schemes used.
 Choice of scrubbing liquors for CO2 and CO.

17. SYNTHESIS OF COKE OVEN +NH3

18. NATURAL GAS
 Principal use –heating ,chemical synthesis
Process description
Gas is pumped from natural gas and petroleum wells to drying units
(absorption ,adsorption or refrigerated compression). separation of
the heavy ends done by either absorption or liquefaction.
Adsorption is not competitive for this operation
the natural gas ,containing over 95% CH4 with the balance as ethane
next sent to purification units for removal of H2S and other
sulphides . Various absorptions and chemical reaction methods are
available with the ethanol amine absorption process in current
favour.

19. Liquefied Petroleum Gases(LPG)
 Principal use-heating ,chemical synthesis.
 Process description
these gases are byproducts from natural gas
separation plants and petroleum refineries. They
consist essentially of purified propane and butane in
various mixtures . The propane fraction only is
supplied for residential fuel in northern winter
climates because of its lower boiling point.

20. The ethanol amine absorption process
e flow sheet indicates the possible physical steps used
for separating moisture,H2S and petrol. Drying can be
either by adsorption or refrigeration ;the heavy end
removal by either absorption or refrigerated
liquefaction .
The choice depends on location and power costs.
Natural gas as the overhead is stripped of H2S in an
ETHANOL AMINE ABSORPTION PROCESS.

21. NATURAL GAS AND LPG TREATMENT