Sh. A.K. De Indraprastha Gas Limited 1. Concern for Pollution: After Independence of India, Delhi, the capital became major centre of commerce, industry and education. Rapid growth of Delhi resulted in significant increase in environmental pollution. Based on the ambient air quality monitored by the Central Pollution Control Board in 1998, it was found that the contribution from vehicles to the ambient air pollution of Delhi was about 65% of total air pollution. This could be understood from the fact that vehicle population increased from a number of 2,35,000 in 1975 to 21,00,000 in 1991 and further to around 37,00,000 vehicles by 1st January 2004 in Delhi. The sector-wise emission of pollutants in Delhi can be seen from the Table. SECTOR-WISE EMISSIONS* IN DELHI (Metric Tonnes per Day) POLLUTANTS UHC SPM NITROGEN OXIDES SULPHUR DIOXIDE CARBON MONOXIDE TOTAL TRANSPORT 310 13 157 11 810 1301 POWER 2 50 143 121 8 324 INDUSTRY 6 60 20 35 128 249 DOMESTIC 2 12 3 12 117 146 TOTAL 320 135 323 179 1063 2020
*Source: Central Pollution Control Board (CPCB), 1998
The above situation had given dubious distinction to Delhi as one of the most polluted city of the world. With the increasing number of pollutants in Delhi’s air and with the background of increasing trend in the use of CNG in the other parts of the world, Public Interest Litigation (PIL) was filed in the Hon’ble Supreme Court of India in 1985 seeking intervention in this matter. The Hon’ble Supreme Court had directed the Government of India to take initiative in promoting the use of CNG, an established clean fuel in the world as transport fuel in Delhi to control the increasing levels of ambient air pollution.
What is CNG? Properties of Natural Gas: CNG is the short form of Compressed Natural Gas. The Natural Gas has less energy density as compared to Liquid Fuel and hence it is compressed to over 200 Kg/cm² (g) pressure to make it CNG for use in the automobile sector. In its natural form it is colourless, odourless, non-toxic and non-carcinogenic. However, this natural gas is mixed with an odorant to add flavour similar to the odour of LPG from a domestic cylinder so as to facilitate detection of its leakage. The typical composition and physical properties of CNG (i.e. Compressed Natural Gas) is as follows: Typical Composition: Methane Ethane Propane CO2 Others Total : : : : : : 88% 5% 1% 5% 1% ____ 100%
Physical Properties : Non-toxic – Natural gas being lead/sulphur free, its use substantially reduces harmful engine emissions. When natural gas burns completely, it gives out carbon dioxide and water vapour - the very components we give out while breathing! Natural gas being lighter than air, will rise above ground level and disperse in the atmosphere, in the case of a leakage. 2
Lighter than air –
Colourless – Odourless –
Natural Gas is available in the gaseous state, and is colourless. The gas in its natural form is odourless, however, ethyl mercaptan is later added as odorant so as to detect its leakage.
Pilot project of GAIL : Objective : A pilot project was initiated by GAIL (India) Ltd. in collaboration with Indian Institute of Petroleum, Dehradun to establish the feasibility of using CNG as an alternative to liquid fuels such as Diesel & Petrol used by buses & automobiles in 3 cities namely Delhi, Mumbai & Baroda. POLLUTION REDUCTION IN CNG FUELLED VEHICLES
The use of CNG in vehicles has lead to considerable reduction in air pollution as is evident from the following data: A. Autorickshaw – Three wheelers: CNG 1.26 1.57 27.60 0.20 (Emission in gram/Km) % Reduction 63.19 71.35 41.82 20.00
Bajaj Three wheeler
Pollutants Petrol HC 3.26 CO 5.48 CO2 47.44 NOx 0.25 Source: Bajaj Auto, the manufacturer of three wheelers B. Passenger Cars:
(Emission in gram/Km) Pollutants Petrol CNG % Reduction Maruti Omni CO...