How are Petrol,Diesel and CNG interrelated each other

How are Petrol,Diesel and CNG interelated each other

 In recent days a lot of heat has been 

generated on the issue of using CNG as a transprt fuel. While the pro CNG group is thrilled by the supreme Court directive fir conversion of city bus fleet to CNG mode the other group is eager to point out that diesel is a better option and CNG os not all that clean. 

Petrol and diesel are the major liquid fuels used in automobiles. On the other hand CNG is a gaseous fuel which is recent entrant in the transport sector. Petrol, diesel and CNG belong to the hydrocarbons family. The quality and quantity of end products are dictated by the nature of crude and technologies used in refineries. 

Both petrol and diesel gave sulphur content in varying proportions. And this is direct relationship with the emmision characteristics. 

Presence of sulphur in fuel causes gaseous and particle emmision. Also, the after burner devices like catalytic converters and particulate traps which are used to reduce the noxious exhaust from automobiles, cannot effectively function due to high sulphur content. Also the hydrogen fuels are inheritently pollitong in nature the extent of which can be minimised but not eliminated.

 The ratio between the carbon and hydrogen atom in the hydrocarbons is closely related to the pollution potential of fuels. Petrol and diesel belong to the long - chain hydrocarbons with larger number of carbon atoms forming the chain with hydrogen atoms on the other hand, the fuels like propane, LPG and CNG belong to the group of short- chain hydrocarbons having lesser number of carbon atoms. Hence the latter are less polluting. 

CNG has been used as an autofuel in several countries as of now, there are more than 1.2 million CNG driven vehicle in the world . Argentina, Canada, Italy, new Zealand and use are among the countries where CNG is being used as an auto- fuel for some years in India, Mumbai has been the first to use CNG, mainly for taxies. 

Notwithstanding limited number of CNG dispensing outlets in Delhi, more than 20000 taxies are using CNG price differential between petrol and CNG prompted the taxies to opt for CNG in Mumbai. 

In Delhi, the switch to CNG was directed by the supreme Court. For various reasons,

[28/05, 6:26 pm] Dinesh Prajapati: It has not been possible to achieve the target . However, the Delhi transport corporation (DTC) has since placed orders for more than 1800 CNG buses while a good number of private operators are yet to make up their mind lack of CNG kits dispensing outlets long filling time and of course, initial expenditure to be incurred on CNG conversation are among the reason cited for hesitation in switching over to CNG buses in a programme of this kind involving major technological trantransformation such teething problems are not unexpected.

 In this context, a question is raised as to whether the entire city bus fleet should be dependent only on one fuel. This is an important issue, which deserves serious consideration. To my mind, it will be judicious to drive multiple choices including CNG, LPG, propane and also diesel of pre determined proportions so that the total pollution load is kept within acceptable limits. 

There is yet another question as to whether ultra low sulphur diesel will be a cost effective if not cleaner option? In response, I am tempted to use the piverb that a bird in hand is better than two in the bush. 

The capital has the advantage of having UBJ pipeline carrying natural gas. So why not avail of this facility when adequate supply of gas is assured. On the other hand the so called low sulphur diesel supplied in the city contains 0.05% sulphur which needs to be reduced at least tto times for supplying ultra low sulphur diesel. While some of the tlrefineries are now geared to producing EURO-III equivalent fuel penalty with 0.035% sulphur content by 2005 , several others are still struggling to achieve 0.05% sulphur in diesel , that too by 2005,According to an estimate provided by the refineries, the total cost of producing 0.05% sulphur diesel will be around Rs 17,000 crores and to produce 0.035% sulphur diesel, the cost will be around Rs 35,000 crores.

Moreover, the refineries will need at least 4 to 5 years for technological upgradation. Alongside improvement of vehicular commission control technology, it will be necessary to build up capabilities for manufacture of state of art catalytic converters and particulate traps.