This document provides information on compressed natural gas (CNG) and liquefied petroleum gas (LPG). It defines CNG and LPG, lists their compositions and properties. CNG has higher methane content while LPG contains more propane and butane. Both are used as alternative fuels, with CNG being cleaner but requiring high-pressure storage while LPG has lower pressure storage. Their emissions and applications in vehicles and industry are also compared.

3. COMPRESSED NATURAL GAS
 DEFINITION
 PROPERTIES
 USES
 ADVANTAGES
 APPLICATIONS

4. COMPRESSED NATURAL GAS
 When the natural gas is compressed, it is
called Compressed Natural Gas (CNG).
 The primary component present in CNG is
methane. It is mainly derived from natural gas.
 The natural gas can either be stored in a tank
of a vehicle as compressed natural gas (CNG)
at 3,000 or 3,600 psi or as liquified natural gas
(LNG) at typically 20-150 psi.

5. The average composition of
CNG is as follows
Constituents Percentage (%)
Methane 88.5
Ethane 5.5
Propane 3.7
Butane 1.8
Pentane 0.5

6. CNG
CNG is made by compressing natural gas (which is
mainly composed of methane [CH4]), to less than 1%
of the volume it occupies at standard atmospheric
pressure
. It is stored and distributed in hard containers at a
pressure of 200–248 bar (2900–3600 psi), usually in
cylindrical or spherical shapes

7. Properties
 1.CNG is the cheapest, cleanest and least
environmentally impacting alternative fuel.
 2. Vehicles powered by CNG produce less
carbonmonoxide and hydrocarbon (HC) emission.
 3. It is less expensive than petrol and diesel.
 4. The ignition temperature of CNG is about
550°C.
 5. CNG requires more air for ignition

8. Uses
 CNG is used to run an automobile
 vehicle just like LPG.

9. Advantages of CNG over LPG
 1.CNG produces less pollutants than LPG.
 2.CNG is cheaper and cleaner than LPG.
 3.The octane rating of CNG is high, hence
the thermal efficiency is more.
 4.It does not evolve sulphur and nitrogen gases.
 5.It mixes very easily with air than the other
gaseous fuels.
 6.Noise level is much less than diesel
 7.CNG vehicle limit 40% less of nitrogen oxide, 90%
less of hydrocarbons, 25% less of CO2

10. Comparison of emission levels between
CNG-driven vehicles and petrol driven
vehicles
Pollutants
Emission levels
Petrol driven
vehicle
CNG driven
vehicle
CO (gm/km) 0.92 0.05
HC (gm/km) 0.36 0.24

11. APPLICATION OF CNG
 (CNG) is a fossil fuel substitute for gasoline (petrol),
diesel, or propane/LPG.
 CNG may also be mixed with biogas, produced from
landfills or wastewater, which doesn't increase the
concentration of carbon in the atmosphere.
 Cars and locomotives.

12. The difference between CNG and LPG
Compressed natural gas
(CNG)
Liquefied petroleum gas
(LPG)

13. LIQUEFIED PETROLEUM GAS (LPG)
 DEFINITION
 USES
 ADVANTAGES
 DISADVANTAGES
 APPLICATIONS

14. LIQUEFIED PETROLEUM GAS
(LPG)
 It is obtained as a by-product during
fractional distillation of crude petroleum oil
or by cracking of heavy oil. It consists of
propane and butane. It can be readily
liquefied under pressure, so it can be
economically stored and transported in
cylinders.

15. The average composition of LPG
is as follows
 Its calorific value is about 25,000 kcal/m3
constituents percentage
N-butane 38.5
Iso butane 37
propane 24.5

16. LPG
 Varieties of LPG bought and sold include mixes
that are primarily propane (C3H8), primarily
butane (C4H10) and, most commonly, mixes
including both propane and butane and
isobutane depending on the season — in winter
more propane, in summer more butane[.
Propylene and butylenes are usually also present
in small concentration. A powerful odorant,
ethanethiol, is added so that leaks can be
detected easily

17. Uses
 1. It is used as a domestic and industrial fuel
 2. It is also used as a motor fuel.

18. Advantages of LPG over gaseous fuels
 1.LPG consists of hydrocarbons, so it burns
cleanly without leaving any residue.
 2.The LPG (hydrocarbons) has higher calorific value
than the other gaseous fuels containing H2 or
CO. The calorific value is 7 times higher than
coal gas and 3 times higher than natural gas.
3.LPG is characterized by high thermal efficiency
and heating rate.

19.  4. It is easy to manipulate.
 5. Comparatively it is less of health hazard, even
in case of leakage.
 6. Needs little care for maintenance.
 7. It is free from CO, so it is less hazardous

20. Disadvantages of LPG over other
gaseous fuels
1. Due to its faint odour, leakage cannot be easily
detected
2. Its octane value is low.
3. Handling must be done under high pressure.
4.LPG is suitable only for the engines working
under high compression ratio.

21. Application of LPG
 It is increasingly used as an aerosol propellant and
a refrigerant, replacing chlorofluorocarbons in an
effort to reduce damage to the ozone layer.
 When specifically used as a vehicle fuel it is often
referred to as autogas.
 Other industrial application includes its use in
portable blow lamps, soldering, welding,
annealing hardening, brazing, steel cutting etc