Environmental Pollution & Hazards of Natural Gas vs. Gasoline

What is CNG?

Natural gas consists mainly of methane (CH ). In addition to this, it usually includes ethane, propane and butane, long-chain hydrocarbons, water, hydrogen sulphide (H S) as well as inert gases such as carbon dioxide (CO ) and nitrogen (N ). The composition, however, depends to a great extent on the deposit.

Natural gas is compressed to 00 bars and carried as CNG  Compressed Natural Gas) in pressure tanks on the vehicle. The gas is usually depressurized to 7 bars by a high-pressure regulator and supplied to the engine induction system through a special mixing device.

In comparison with gasoline, natural gas has an unfavorable  volumetric energy content. Therefore, natural gas can only practically be applied in transport after being processed to a fuel with higher volumetric energy content.

Environmental View

Not long ago, the world used to be free of toxic compounds in the atmosphere, unlike today when every other person is contributing a large amount of waste gasses in the air. These waste gasses exit through the car’s exhaust pipe and into the atmosphere, free, free to pollute the world.

The topic for debate is that which fuel contributes more, CNG Compressed Natural Gas] OR Normal Pump Gasoline. [ISOOctane].
In theory, CNG is supposed to be less harmful for the environment. Carbon monoxide and non-methane hydrocarbons are reduced by upto 90 % compared with gasoline (on a car without a catalytic converter). The way catalytic converter designed for gasoline remains largely ineffective for the degradation of nitrogen oxides and methane in natural gas operation mainly due to low carbon monoxide values.
However, the quality of CNG in our country has led many to believe that it is not the clean fuel as it should be. Local CNG suppliers use low quality mixtures, introduce toxins into the gas stream to save up money and increase volume. Even after looking at these factors, CNG is way cleaner in an internal combustion engine than Gasoline.

Advantages of CNG Over Gasoline:

- 20- 25 % less carbondioxide emission.
- up to 90% less carbon monoxide emission.
- 75-90% less non-methane hydrocarbons.
- Approximately 80% less ozone deterioration potential.
- No Acid Smell from the exhaust gasses.
- No volume losses through vaporization from the tank while    refilling.
- No carcinogenic substances.
- Less Expensive than gasoline.

Disadvantages of CNG Over Gasoline:

- Heavy methane gas emission (global warming).
- Approximately 50 – 100 % more nitrogen dioxide emission.
- 20- 30% less power output with existing dual fuel engines at optimized conditions.
- Additional fuel station network necessary increasing Fire Risk..
- Weight and Space requirements for gas cylinders in a vehicle.
- Frequent Fill-ups.
- Dangerous Fire Hazard in case of Accident.
- Dangerous Explosion Hazard in case of Accident.
- Fire Hazard in case of gas leaks &/or substandard cylinders.
- Low Reliability.