Petrol monopoly...
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24-04-2012, 12:29 AM (This post was last modified: 24-04-2012 01:41 AM by Filox.)
Petrol monopoly...
We already had some discussions here about cars, their technology, the MPG, diesel-petrol-LPG-hybrid-hydrogen... I have stated that the oil industry has a monopoly and is deliberately pushing petrol as the best fuel you can buy, all other are being pushed back little by little. I didn't have any specific evidence, it is all collected in my head little by little, by reading between the lines, by observing the bigger picture. So, yesterday I came across some articles that have clearly shown me I was right, the panic and the fear are the weapons for mass control.

And then this comes out...

http://www.forbes.com/sites/williampentl...accidents/

Now, I do not deny that the diesel engine produces CO, CO2 and all other pollutants, but to put out this whole article, just to bash on diesel technology, without even mentioning petrol and it's environmental/health issues and than comparing the two is just ridiculous and clearly a deliberate attack on the cheaper and more economical fuel.

Then I came across this one...

http://www.telegraph.co.uk/earth/environ...sions.html

So, the best biofuel, the biodiesel, that is known to be far less polluting for the last 70 years, is now suddenly producing 4 times (!) more CO2 than regular petrol and diesel. Like, it was so incredibly hard to measure the CO2 emissions any time during history. They also like to say that the production of biodeisel is very harmful, dangerous and polluting. They like to say all that without comparing this directly to the oil industry and how much does making of petrol and diesel actually pollute.

Very, very onesided stories, written with the clear intend to keep the petrol engines still on top sale, thus pushing the petrol sale to still be No. 1, while the price of petrol keeps going up and the MPG in (petrol) cars stays where it is... Bear in mind that these articles are starting to come out as the world is in crisis, the petrol price is going sky-high and people are looking for the cars that use less fuel, thus the diesel engine cars. It appears that the diesel is not preferable fuel for the oil industry, since diesel engines use less fuel.

I'm, probably crazy, seeing things and conspiracies everywhere, but do you see the pattern here?

Tongue

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24-04-2012, 05:08 AM (This post was last modified: 25-04-2012 04:50 AM by robotworld.)
RE: Petrol monopoly...
4 times CO2?? That's a joke. Here, let's have some chemistry.

Reaction 1: CH3CH2OH (ethanol) + 3O2 -> 2CO2 + 2H2O
Reaction 2: C8H18 (Shortest alkane in diesel) + 12.5O2 -> 8CO2 + 9H2O

In other words, one molecule of ethanol gives 2 molecules of CO2 per complete combustion while one molecule of octane gives 8CO2 molecules per complete combustion.

Standard Enthalpy Change of Combustion (To obtain the amount of energy generated per mole of fuel burnt)

Reaction 1: -1370.7kJ/mol
Reaction 2: -5330kJ/mol

This means for every mole of fuel burnt, diesel (octane) provides approximately 3.9 times more energy than burning ethanol. However, for every mole of fuel burnt, octane gives out 4 times more CO2 than ethanol.

Let's convert it to kJ/g to be fair. (One mole of octane has a molar mass greater than that of one mole of ethanol
Reaction 1: Molar Mass of ethanol is 46g/mol. Thus enthalpy change of combustion in terms of kJ/mol is -29.8kJ/g.
Reaction 2: Molar Mass of octane is 114g/mol. Thus enthalpy change of combustion in terms of kJ/mol is -46.8kJ/g

For every gram of fuel burnt, octane gives 1.57 times more energy than ethanol.

How about the CO2 emissions per gram?
Reaction 1: 1 gram of ethanol = 0.02 moles, which gives 0.04 moles of CO2
Reaction 2: 1 gram of octane = 0.00877moles, which gives 0.07 moles of CO2

For every gram of fuel burnt, octane gives out 1.75 times more CO2 than ethanol.

Ethanol still WINS, hands down. Any chemistry majors willing to check my calculations? Hope I did not screw up somewhere Tongue

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24-04-2012, 11:58 PM
RE: Petrol monopoly...
OK, you did this with ethanol, but I am pretty sure you could to the same thing with biodiesel and regular diesel compared to regular petrol. I mean, people could measure the dangerous emissions for a very long time now, yet, somebody has decided that it was never correct and that only now, in the year 2012, we have made some ground breaking discoveries on the dangers of diesel/biodiesel.

I call a complete and utter bullshit on these claims.

Thanx for the chemistry calculations.

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25-04-2012, 03:37 AM
RE: Petrol monopoly...
I'll gladly do the math again for bio-diesel. In this case I'll use ethyl stearate and methyl linoleate as bio-diesel compared to petro-diesel, which I will still use octane. Ethyl stearate and methyl linoleate are usually derived from soy beans.

Ethyl stearate: C20H40O2
Methyl linoleate: C19H34O2

C20H40O2 + 29O2 = 20CO2 + 20H2O

2C19H34O2 + 53O2 = 38CO2 + 34H2O



1 gram of ethyl stearate = 0.0032 moles which gives 0.064 moles of CO2
1 gram of methyl stearate = 0.0034 moles which gives 0.0646 moles of CO2

At this point I realised I made a huge mistake in my previous calculations, and have edited accordingly with new values. (Ethanol still wins, but what about bio-diesel?)

1 gram of octane gives out 0.07 moles of CO2

We can gain the conclusion that burning one gram of octane still gives out more CO2 than bio-diesel. Note that I'm kind to use the shortest alkane chain in diesel already.


But compared to petrol, what will the values be like? For that, I will be using butane (shortest alkane chain in petrol) and dodecane (longest alkane in petrol)

2C4H10 + 13O2 = 8CO2 + 10H2O

2C12H26 + 37O2 = 24CO2 + 26H2O



1 gram of butane = 0.017 moles which gives 0.068 moles of CO2
1 gram of dodecane = 0.0059 moles which gives 0.0708 moles of CO2

Based solely on CO2 emissions, bio-diesel wins. Petrol and regular diesel gives out more CO2 per gram than bio-diesel. Consider that you are pouring litres and litres of fuel into your tank, and a 0.004 mole difference can lead to a huge difference.

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26-04-2012, 05:52 AM
RE: Petrol monopoly...
Thank you my good sir, you have just proven my point, they are fucking up the scientific data for the purpose of selling more petrol cars than other ones.

But then again, if you look at the news that reported this, it all becomes clear as olive oil, Telegraph and Forbes...

Jerks!

Smile

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