CNG!!!

I was wonder about this CNG when i was seen this in all motor vehicles in Delhi. Keenly i entered into Internet ....

(Blue Diamond Symbol used in Fleets North America )
Got it as Compressed Natural Gas its as like the LPG.
CNG (Furnished in Fleets of Delhi Metros)

CNG ( Compressed Natural Gas ) is usually around 70-90% methane with 10-20%
ethane, 2-8% propanes, and decreasing quantities of the higher HCs up to
pentane. The major disadvantage of compressed gaseous fuels is the reduced
range. Vehicles may have between one to three cylinders ( 25 MPa, 90-120

litre capacity), and they usually provide about 50% of the gasoline range.

LPG ( Liquefied Petroleum Gas ) is predominantly propane with iso-butane
and n-butane. It has one major advantage over CNG, the tanks do not have
to be high pressure, and the fuel is stored as a liquid. The fuel offers
most of the environmental benefits of CNG, including high octane - which
means higher compression, more efficient, engines can be used. Approximately
20-25% more fuel than gasoline is required, unless the engine is optimised
( CR 12:1 ) for LPG, in which case there is no decrease in power or any
significant increase in fuel consumption [4,5].

Whats Special in it?

CNG is a fossil fuel substitute for gasoline (petrol), diesel, or propane fuel. Although its combustion does produce greenhouse gases, it is a more environmentally clean alternative to those fuels, and it is much safer than other fuels in the event of a spill (natural gas is lighter than air, and disperses quickly when released).

What is LPG?

What is LPG? LPG or LP Gas is the abbreviation of Liquefied Petroleum Gas. This group of products includes saturated Hydrocarbons - Propane (C3H8) and Butane (C4H10), which can be stored/transported separately or as a mixture. They exist as gases at normal room temperature and atmospheric pressure.

Why is it called Liquefied Petroleum Gas? This is because these gases liquefy under moderate pressure. They liquefy at moderate pressures, readily vaporizing upon release of pressure. It is this property that permits transportation of and storage of LP Gas in concentrated liquid form.

Where does LPG come from? LPG comes from two sources. It can be obtained from the refining of crude oil. When produced this way it is generally in pressurized form. LPG is also extracted from natural gas or crude oil streams coming from underground reservoirs. 60% of LPG in the world today is produced this way whereas 40% of LPG is extracted from refining of crude oil.

What is commercial Propane & Butane? Ideally products referred to as "propane" and "butane" consist very largely of these saturated hydrocarbons; but during the process of extraction/production certain allowable unsaturated hydrocarbons like ethylene, propylene, butylenes etc. may be included in the mixture along with pure propane and butane. The presence of these in moderate amounts would not affect LPG in terms of combustion but may affect other properties slightly (such as corrosiveness or gum formation).

Advantages of LPG?

• Because of its relatively fewer components, it is easy to achieve the correct fuel to air mix ratio that allows the complete combustion of the product. This gives LPG its clean burning characteristics.
• Both Propane and Butane are easily liquefied and stored in pressure containers. These properties make the fuel highly portable, and hence, can be easily transported in cylinders or tanks to end-users.
• LPG is a good substitute for petrol in spark ignition engines. Its clean burning properties, in a properly tuned engine, give reduced exhaust emissions, extended lubricant and spark plug life.
• As a replacement for aerosol propellants and refrigerants, LPG provides alternatives to fluorocarbons, which are known to cause deterioration of the earth's ozone layer.

The clean burning properties and portability of LPG provide a substitute for traditional fuels such as wood, coal, and other organic matter. This provides a solution to de-forestation and the reduction of particulate matter in the atmosphere (haze), caused by burning the traditional fuels.

Petro Product - What is HSD?

High Speed Diesel

(Simply Called Diesel)

A diesel fuel is any fuel suitable for burning in diesel or compression ignition engines. Petroleum diesel fuels may be distillates or blends of distillates and residual fuels.

In a compression ignition engine, air alone is drawn into cylinder and compressed until it is very hot (about 500 deg C). At this stage, finely atomized fuel is injected at a very high pressure, which is ignited by the heat of compression and hence the term compression ignition (C.I.). A spark ignition engine on the other hand, relies upon a carburetor to supply into the cylinder a mixture of gasoline vapour and air, which after compression, is ignited by a spark.

The average compression ratio of a diesel engine is much higher (about 15:1) than that of a gasoline engine (about 8:1) and this is the reason for the higher thermal efficiency of the diesel engine (about 33% as compared to about 25% of the gasoline engine) which makes for economy in operation.

Two main grades of diesel fuel are marketed in India, High Speed Diesel (HSD) and Light diesel oil (LDO). The former is a 100% distillate fuel while the latter is a blend of distillate fuel with a small proportion of residual fuel.

HSD is normally used as a fuel for high speed diesel engines operating above 750 rpm i.e. buses, lorries, generating sets, locomotives, pumping sets etc. Gas turbine requiring distillate fuels normally make use of HSD as fuel. LDO is used for diesel engines, generally of the stationery type operating below 750 rpm

CETANE NUMBER

The most accurate method of assessing the ignition quality of a diesel fuel is by measuring its cetane number in a test engine, the higher the cetane number the higher the ignition quality. The cetane number of a fuel is defined as the percentage of cetane, arbitrarily given a cetane number of 100, in a blend with alphamethyl-naphthaline (cetane number -0 ), which is equivalent in ignition quality to that of the test fuel.

CARBON RESIDUE

Different fuels have different tendencies to crack and leave carbon deposits when heated under similar conditions. This property is normally measured by the Conradson or the Ramsbottom coke tests. In these tests, a sample of the fuel is heated without contact with air under specified conditions and the weight of carbon residue remaining after the test is expressed as a percentage of the weight of the sample.

Petrol Products - What is Motor Sprit

(Simply Called Petrol)

Motor gasoline is meant a mixture of the lighter fractions of petroleum composed of hydrocarbons having boiling points in the range approximately 30 ⁰C to 215 ⁰C. Straighfluidizet run stream from Crude Distillation Unit (CDU) and cracked stream from d Catalytic Cracker Unit (FCCU) with the above boiling range are blended to obtain required quality Motor Gasoline. It may contain small quantities of chemical e.g. tetraethyl lead, etc. added to improve its performance.

Motor spirit, Petrol and Gasoline are different nomenclatures for the same product. Motor spirit is of British origin while Gasoline is of American origin.

SPECIFICATIONS

Motor gasoline are currently marketed meeting Bureau of Indian Standards Specification, IS : 2796-1971, for Motor Gasoline 87 and 93 Octane. Besides Motor Gasoline (MT 80) is marketed as defense applications.

The most important property of a gasoline is its Octane Number, (ON), which indicates whether the fuel will knock in an engine. Knock or "Pink" is the audible explosion (detonation) produced when a portion of the fuel charge in the cylinder ignites spontaneously ahead of the normal flame front. All things being equal, knock is a direct function of the fuel alone, some fuels being more prone to it than others. It is determined in the CFR (Co-operative Fuel Research) engine and is defined as the percentage of iso-octane, arbitrarily given an O.N. of 100, in a blen with normal heptane (O.N.=0) which matches the fuel under examination.

Motor gasoline is normally rated in the CFR engines under two sets of conditions which differ in severity. The Research or F.1 method gives a rating more applicable to operation under mild conditions, while the Motor or F.2 method may be a better criterion when operating at higher speeds and loads.

The higher the compression ration of an engine the higher is its thermal efficiency. The limiting compression ration that can be utilized is set by the anti-knock characteristics of the fuel; thus increasing of the octane number permits the use of higher compression rations and gives more power, higher efficiency and lower fuel consumption. However, no advantage is gained by increasing the octane number beyond that necessary to give knock free performance.

The CFR octane number is a rating on one particular type of engine under a given set of conditions and cannot by itself be used to predict the road octane number (RON) of the fuel under varying conditions of operations.

IS- 2796-1971 SPECIFICATION OF MS (INDIA)

No.	Characteristics	Test Method	87 Octane	93 Octane
1	Colour, Visual	-	Orange	Red
2	Copper Strip Corrosion for 3 hours at 50 0C	P-15	Not worse than No.1
3	Density at 15 0C g/ml	P-16	0.730	0.735
4	Distillation
	Initial boiling point 0C		50	45
	Recovery upto 75 0C,%v,min.		10	10
	Recovery upto 125 0C,%v,min.		50	50
	Recovery upto 180 0C,%v,min.		90	90
	Final boiling point 0C, Max		2	2
5	Octane Number (research Method)	P-27	87	93
6	Oxidation stability in Minutes, min.	P-28	360	360
7	Residue on evaporation, mg/100 ml, max.	P-29	4.0	4.0
8	Sulphur, % wt.max.	P-34	0.25	0.20
9	Lead content, g/lmax	P-38 or 82	0.56	0.80
10	Reid vapour pressure at 38 0C kgf/cm2, max	P-39	0.70	0.70