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

Photovoltaic Terms 2

Load - Electrical power being consumed at any given moment. The load that an electric generating system supplies varies greatly with time of day and to some extent season of year. Also, in an electrical circuit, the load is any device or appliance that is using power.

Parallel connected - A method of connection in which positive terminals are connected together and negative terminals are connected together. Current output increases and voltage remains the same. (See also series connected.)

Photovoltaic cell - The semiconductor device that converts light into dc electricity. The building block of photovoltaic modules.

Series connected - A method of connection in which the positive terminal of one device is connected to the negative terminal of another. The voltages add and the current is limited to the least of any device in the string. (See also parallel connected.)

Solar constant - The rate at which energy is received from the sun just outside the earth's atmosphere on a surface perpendicular to the sun's rays. Approximately equal to 1.36 kW/m2.

Thick cells - Conventional cells, such as crystalline silicon cells, which are typically from 4 to 17 mils thick. In contrast, thin-film cells are several microns thick.

Thin-film cells - Photovoltaic cells made from a number of layers of photo-sensitive materials. These layers are typically applied using a chemical vapor deposition process in the presence of an electric field.

Voltage regulator - A device that controls the operating voltage of a photovoltaic array.

Photovoltaic Terms 1

Cell efficiency - The ratio of the electrical energy produced by a photovoltaic cell (under full sun conditions or 1 kW/m2) to the energy from sunlight falling upon the cell.

Charge controller - A component that controls the flow of current to and from the battery subsystem to protect the batteries from overcharge and over discharge. The charge controller may also monitor system performance and provide system protection.

Diffuse radiation - Sunlight received indirectly as a result of scattering due to clouds, fog, haze, dust or other substances in the atmosphere.

Direct radiation - Light that has traveled in a straight path from the sun (also referred to as beam radiation). An object in the path of direct radiation casts a shadow on a clear day.

Flat-plate array - A photovoltaic array in which the incident solar radiation strikes a flat surface and no concentration of sunlight is involved.

Fresnel Lens - A concentrating lens, positioned above and concave to a PV material to concentrate light on the material.

Grid-connected - An energy producing system connected to the utility transmission grid. (Also called utility interactive.)

Hybrid system - A power system consisting of two or more power generating subsystems (e.g., the combination of a wind turbine and a photovoltaic system).

Insolation - The amount of sunlight reaching an area, usually expressed in watts per square meter per day.

How does solar energy work?

Solar Electric or Photovoltaic Systems convert some of the energy in sunlight directly into electricity. Photovoltaic (PV) cells are made primarily of silicon, the second most abundant element in the earth's crust, and the same semiconductor material used for computers. When the silicon is combined with one or more other materials, it exhibits unique electrical properties in the presence of sunlight. Electrons are excited by the light and move through the silicon. This is known as the photovoltaic effect and results in direct current (DC) electricity. PV modules have no moving parts, are virtually maintenance-free, and have a working life of 20 - 30 years.

Solar energy is a major contributor to the overall growth of renewable energy resources, and global output is expecting to be 26GWH by 2025.

Energy Links

http://www.eia.doe.gov/kids/energyfacts/index.html
http://www.edugreen.teri.res.in/explore/n_renew/energy.htm
http://www.scienceonline.co.uk/energy/renewable-energy.html
http://www.itpi.co.in/Resources/Renewable_energy/Renewable_energy.htm

GEOTHERMAL ENERGY

Geothermal energy is the natural heat generated from within the earth. Undemeath the earth’s relatively thin crust, temperatures range from 1000 to 4000 C and in some areas, pressure exceeds 20,000 pounds per square inch (Psl).

Geothermal energy is most likely generated from radioactive thorium, pot assium and uranium dispersed evenly throughout the earth’s interior which produce heat as part of the decaying process. Volcances, hot springs, geysers and fumaroles are natural clues as to the presence of geothermal resources near the surface and perhaps where economic drilling operations can tap their heat and pressure. About 10 percent of the worlds land mass contains accessible geothermal resources and could provide several million quads of energy annually.

Geothermal energy is derived using the earth’s natural fluids to extract thermal energy that can be sent through turbines to generate electricity or be used directly e.g. direct heating and industrial process heat. Conventional oil and gas drilling methods are primarily used to extract ge0thermal resources using harder drill bills to combal corrosion and high temperature. As it is uneconomical to transport the thermal energy over long distances, the end use is often located near the source.

OCEAN THERMAL ENERGY CONSERVATION

OTEC utilizes the temperature different between warm (26 C) surface waters of low latitude tropical oceans and the cool deep waters (5-10 C) lying below a depth of a few hundred meters to run a turbine and a generator via a heat exchanger and a suitable medium (e.g. ammonia or low pressure steam).

OTEC is a method of using solar energy stored as a temperature difference in the oceans.The earth’s oceans absorb solar radiation the major part of which they store as thermal energy in the warm surface waters. On the other hand, cold water layers move slowly from polar regions towards the equator at depths of less than 100 m. Thus, a vertical temperature difference of up to 25 C exists throughout the year at many tropical locations According to the fundamental laws of thermodynamics, this temperature gradient can be exploited as an energy source.

The ocean thermal gradient does not vary significantly from day to night and hence can be regarded as a steady source of energy. It does have however, a seasonal variation which increases with the distance from the equator.The natural power potential of the thermal gradient energy is estimated to be as large as 10 W (10 TW). Obviously it is not technically feasible to extract all this energy.

A fair estimation would be approximately 10 W as against the world installed electrical generation capacity of the order of 10 W.In India activities in this area are coordinated by the OTEC Cell at Indian Institute of Technology, Madras. A feasibility study of setting up a 5 to 8 MW pilot R & D OTEC plant off the main Anandman Islands is ready and a proposal for a feasibility study for installation of a 100 MW OTEC plant off Madras is under consideration.