Alternative Fuels CNG and LPG

ALTERNATIVE FUELS : CNG AND LPG

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STUDENT NO NAME

104135576 BHALAJI

103970268 MUNAWAR

104149267 SURESH

Alternative fuels :

Liquefied petroleum gas (LPG) & Compressed natural gas (CNG)

I.C.ENGINES


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14 • Dedicated fuel, Bi‐fuel, Dual fuel

15 • Fuel system layouts

16 • Questions

PRESENTATION OVERVIEW

4 • Liquid petroleum gas (LPG)

5 • Production process

6 • Comparison : Properties

7 • Co2 Emission comparison

8 • Advantages, drawbacks

9 • Compressed natural gas (CNG)

10 • Production process

11 • Comparison : Properties

12 • Emission comparison

13 • Advantages, drawbacks

1 • Why alternative fuels ?

2 • What are all the alternate fuels ?

3 • Features comparison

4 • Questions

ALTERNATIVE FUELS : CNG AND LPGAlternative fuels, also known as non‐conventional fuels, are any materials or substances that can be used as fuels, other than conventional fuels.

Why Alternative Fuels?

As the cost of conventional fuels goes up, the interest in other fuel sources increase

In some cases, alternative fuels are more environmentally friendly ( Less emissions )

Alternate fuels found abundance in nature.

Most of the alternate fuels are safer.

Some alternative fuels are more energy efficient.

Some well known alternative fuels used in automobiles vehicles are,

Natural gas ( CNG & LNG ) Propane (LPG) Ethanol Methanol Hydrogen Biodiesel Electricity

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FEATURES COMPARISONGasoline Diesel Compressed Natural Gas

(CNG)Propane (LPG)

Chemical Structure C4 to C12 C8 to C25 CH4 (83‐99%),C2He (1‐13%) C3H8 (majority) and C4Fl10 (minority)

Fuel Material Crude Oil Crude Oil Underground reservesA by‐product of etroleum refining or natural gas

processing

Storage pressure Normal Normal 200 bar 6 bar

Fuel type Liquid Liquid Compressed gas Liquid

Octane rating 91 – 97 38 – 45 cetane 130 110

Gasoline Gallon Equivalent (GGE)

100%1 gallon of diesel has 113% of the energy of one gallon of gasoline.

* 5.66 pounds or 126.67 cu. ft. of CNG has 100% of the energy of

one gallon of gasoline.

1 gallon of propane has 73% of the energy of one

gallon of gasoline.

Energy Content (Lower heating value)

116090 Btu/gal (g) 128450 Btu/gal (g) 20,268 Btu/lb (g) 84,950 Btu/gal (g)

Price $3.45/gallon $3.91/gallon $2.09/GGE * $2.96/gallon

* Gasoline gallon equivalent (GGE) or gasoline‐equivalent gallon (GEG) is the amount of alternative fuel it takes to equal the energy content of one liquid gallon of gasoline (1 gasoline gallon equivalent (GGE) means 5.660 pounds of natural gas)


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Propane, also called LPG, liquefied petroleum gas, or LP gas, is a widely used highly efficient

and clean burning fuel.

Varieties of LPG include primarily propane (C3H8), butane (C4H10) and, most commonly,

including both propane and butane and isobutane depending on the season — in winter

more propane, in summer more butane. Propylene and butylenes are usually also present

in small concentration.

A powerful odorant (ethanethiol) is added so that leaks can be detected easily.

Cleaner

Propane vehicles can produce fewer ozone‐forming emissions than vehicles powered by

reformulated gasoline

Economical

The cost of a gasoline‐gallon equivalent of propane is generally less than that of gasoline, so

driving a propane vehicle can save money.

LIQUID PETROLEUM GAS (LPG)

The average composition of LPG

constituents percentage

N‐butane 38.5

Iso butane 37

propane 24.5

C3H8 - Propane

C4H10 - Butane


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LIQUID PETROLEUM GAS (LPG) PRODCTION PROCESS

It is obtained as a by‐product during fractionaldistillation of crude petroleum oil or by cracking ofheavy oil. It consists of propane and butane.

It can be readily liquefied under pressure, so itcan be economically stored and transported incylinders.


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Fuel Properties Gasoline Diesel LPGFormula C4 to C12 C8 to C12 C3H8

Molecular Weight 100‐105 200 44.09Carbon 85‐88 84‐87 82Hydrogen 12.15 13‐16 18Oxygen 0‐4 0 0

Freezing Point, °C ‐40 ‐40 to ‐1 ‐187Boiling Point, °C 27‐225 188‐343 ‐42

Vapour Pressure, kPa 48‐103 <1 1303Viscosity, mPa‐s 0.37‐0.44 2.6‐4.1 0.102Latent Heat of

Vaporisation, kJ/kg 349 233 426

Flash Point, °C ‐43 74 ‐104Auto ignition

Temperature, °C 257 316 457

Flammability Higher Limits, Vol % 7.6 6 9.5

Stoichiometric Air‐Fuel Ratio, Weight 14.7 14.7 15.7

Octane Number 88‐100 40‐55(Cetane) 112

LPG PROPERTIES COMPARISON


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CO2 EMISSION COMPARISON


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LIQUID PETROLEUM GAS (LPG)

ADVANTAGES OF LPG DRAWBACKS OF LPG

Cost : LPG is cheaper than petrol (up to 50%)Cost: The initial cost for converting your vehicle to LPG can cost up to $3000. However the average car can repay the cost of the conversion in about 2 years

Emission: It produces less exhaust emissions than petrol

Availability: It isn't highly available.

Life : It is better for the engine and it can prolong engine life Storage: The gas tank takes up a considerable

amount of space in the car boot

Efficiency: Has a higher octane rating than petrol (108 compared to 91) hence the thermal efficiency is more.


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Natural gas is produced either from gas wells or in conjunction with crude oil production. Because of the gaseous nature of this fuel, it must be stored onboard a vehicle in either a

compressed gaseous state or in a liquefied state Natural Gas is composed of approximately 97% methane. Natural Gas is colorless, odorless, and non‐toxic.

Cleaner It is considered to be the cleanest fossil fuel because it produces fewer emissions than other

fuels when burned. Compared to gasoline or diesel, Natural Gas has the least amount of carbon. Natural Gas is

CH4, Diesel C14H30, and Gasoline C8H18. CNG vehicles produce approximately 25% less CO2 than gasoline or diesel. They also produce approximately 80% less nitrogen oxide than gasoline or diesel and

approximately 90% less particulates.

Economical Natural Gas is less expensive than gasoline or diesel. A gasoline gallon equivalent (gge) of Natural Gas is approx. $1.50 to $2.50. A diesel gallon equivalent (dge) of Natural Gas is approx. $1.75 to $2.50.

Safer Natural Gas has a high ignition temperature of approximately 1200 F compared to Diesel which

is 494 F and Gasoline which is 536 F. Natural Gas is lighter than air, will not lay on the ground, and it dissipates when released.

COMPRESSED NATURAL GAS (CNG)

The average composition of CNG

Constituents (%)

Methane 88.5

Ethane 5.5

Propane 3.7

Butane 1.8

Pentane 0.5


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NATURAL GAS PRODCTION PROCESS

DRILL RIG

Extraction Separation Processing Compression Storage


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Fuel Properties Gasoline Diesel CNGFormula C4 to C12 C8 to C12 CH4

Molecular Weight 100‐105 200 16Carbon 85‐88 84‐87 75Hydrogen 12.15 13‐16 25Oxygen 0‐4 0 0

Freezing Point, °C ‐40 ‐40 to ‐1 ‐182Boiling Point, °C 27‐225 188‐343 ‐162

Vapour Pressure, kPa 48‐103 <1 N/AViscosity, mPa‐s 0.37‐0.44 2.6‐4.1 0.01Latent Heat of

Vaporisation, kJ/kg 349 233 510

Flash Point, °C ‐43 74 ‐188Auto ignition

Temperature, °C 257 316 540

Flammability Higher Limits, Vol % 7.6 6 15

Stoichiometric Air‐Fuel Ratio, Weight 14.7 14.7 17.2

Octane Number 88‐100 40‐55(Cetane) 120

CNG PROPERTIES COMPARISON

PRICE COMPARISON


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An engine running on petrol for 100 km emits 22,000 gramsof CO2, for same distance on CNG emits only 16,275 grams ofCO2.

CNG is essentially CH4 with a c.v. of 900 kJ/mol. It burns withoxygen to produce 1 mole of CO2 and 2 moles of H2O. Bycomparison, petrol is essentially C6H6 with a c.v. of 3,300kJ/mol and this burns to produce 6 moles of CO2 and 3 molesof H2O.

CNG vehicle limit 40% less of nitrogen oxide, 90% less of hydrocarbons, 25% less of CO2

PollutantsEmission levels

Petrol driven vehicle

CNG driven vehicle

CO (gm/km) 0.92 0.05

HC (gm/km) 0.36 0.24

CNG EMISSION COMPARISON


ADVANTAGES OF CNG DRAWBACKS OF CNG

Cost : Natural gas costs are lower than gasoline. On average, natural gas costs one‐third less than gasoline at the pump.

High Cost: The high cost of implementing this technology is one of the stumbling blocks. Buying a natural gas vehicle will be more expensive than a petroleum car as they are not as popular and readily available. Overall costs of a NGV compared to a gasoline‐

powered car. NGVs tend to cost $3500 to $6000 more than gasoline powered ones

Emission: Per unit of energy, natural gas contains less carbon than any other fossil fuel, and thus produces lower carbon dioxide (CO2)

emissions per vehicle mile traveled.

Speed: Natural gas vehicles are not as fast as their gasoline counterparts. limited driving range of NGVs, which is typically

about half that of a gasoline‐powered vehicle.

Availability : There are huge amounts of natural gas deposits available mainly due to the fact that natural gas has not been used as much as petroleum. Although a non‐renewable resource, natural gas deposits

will not be depleted in our lifetime

Storage: Like with gasoline you will need a storage tank in your car for natural gas. Unfortunately this tank is huge and, as it is

normally installed in your trunk, you will have basically no trunk space available afterwards

Compression Ratio: Natural gas vehicle engines have a very high compression ratio, burning most of the fuel and leaving very few by

products behind.

Efficiency: The octane rating of CNG is high, hence the thermal efficiency is more.

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ADVANTAGES & DRAWBACKS OF CNG


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Dedicated fuel, Bi-Fuel, Dual-Fuel ?

Dedicated – A dedicated CNG vehicle is one that runs only on CNG. It can be either a new vehicle with a CNG engine or a repower. In either case, the old fuel tank is normally removed and replaced with CNG Cylinders. This is a great choice for vehicles running predictable routes with access to company‐owned fueling stations (for example, Food & Beverage delivery trucks and School Buses).

Dual Fuel – Technically, a dual fuel is categorized by the EPA as a “mixed fuel” because it blends natural gas with diesel by injecting it into the turbocharger BUT there is a big difference. The vehicle can still run on 100% diesel. That means if you run out of CNG you keep right on going, just like you did in the old days, running on diesel. You keep your existing diesel tanks and install additional CNG cylinders that extend the range. Depending on your load, a dual fuel system will use up to 50% CNG on average. This is a great choice for existing fleet customers that need range and fuel flexibility and do not want to go through the expense of replacing vehicles that have hundreds of thousands of miles remaining in their life.

Bi‐Fuel – Bi‐fuel systems are also called “switchable” systems because you can switch between gasoline or CNG. Most conversions we do for light duty (new or used trucks) are bi‐fuel because they give the customer the best of both worlds. You can run on CNG as long as you have fuel in the tank and switch over to gasoline if you run out. Most modern bi‐fuel systems are fully automated, switching to gasoline when they need to and then automatically switching back once the CNG tank is filled. Bi‐fuel vehicles come equipped with two fuel gauges and a switch to move from CNG to gasoline if the driver desires.


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VEHICLE LAYOUT

DEDICATED CNG FUEL DEDICATED LPG FUEL


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Use of combination fuels(CNG/LPG+DIESEL/GASOLENE)

Natural gas is the ideal fossil fuel to minimize the exhaust‐gas emissions of modern dual‐fuel diesel engines. Also the costs of maintenance and repair will be reduced considerably.

In this process, a very small percentage of between 1 and 10% liquid heavy fuel or diesel oil is injected.During the intake stroke, gas is admitted just before the inlet valves. The liquid fuel ignites the air/gas mixture.

The advantage is that the exhaust gases are cleaner than when heavy‐fuel oil or diesel oil are combusted. Gaseous fuel contains fewer carbon atoms than a liquid fuel therefore reducing CO2production. The emission of soot particles and the sulphur content are significantly reduced. Contamination of the engine decreases

Dual-Fuel (DF)


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Bi‐fuel vehicle

Bi‐fuel vehicles are vehicles with multi fuel engines capable ofrunning on two fuels.

On internal combustion engines one fuel is gasoline or diesel,and the other is an alternate fuel such as natural gas (CNG),LPG, or hydrogen.

The two fuels are stored in separate tanks and the engine runson one fuel at a time.

Bi‐fuel vehicles have the capability to switch back and forthfrom gasoline or diesel to the other fuel, manually orautomatically.

Normally, standard gasoline vehicles are retrofitted inspecialized shops, which involve installing the gas cylinder inthe trunk and the LPG or CNG injection system andelectronics.

The most common technology and alternate fuel available inthe market for bi‐fuel gasoline cars is Autogas (LPG), followedby natural gas (CNG), and it is used mainly in Europe. TheNetherlands or the Baltic states have a large number of carsrunning with LPG. Italy currently has the largest number ofCNG vehicles, followed by Sweden. They are also used inSouth America, where these vehicles are mainly used astaxicabs in main cities of Brazil and Argentina.


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Thank you for your attention. Questions ?

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Alternative Fuels CNG and LPG