A Chemistry Lesson for Steven Harper (667 hits)
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Submitted by The Nick <nickuhlig.at.gmail.com> (View user info) at 2006-07-10 18:31:37 EDT
THe newly elected conservative government of Canada has recently announced plans to legislate hte addition of ethanol to gasoline in Canada as part of its "made in Canada" solution to Kyoto (a euphemism for "do nothing and then buy carbon credits").
They have stated that it is a good idea because ethanol is "cleaner burning" and can be derived from the fermentation of just about anything with sugar in it, once oyu add yeast.
Unfortunately, nobody in the Canadian government seems to have taken chemistry class, because the products of the combustion of any hydrocarbon, alcohols included, are WATER AND CARBON DIOXIDE. WHen gasoline is burned, it produces WATER AND CARBON DIOXIDE. Also, when ethanol is burned, it produces WATER AND CARBON DIOXIDE.
But let's not let that deter us. Maybe ethanol is more efficient? Easier to get? Let's find out together through the magic of chemistry and math!
ETHANOL: C2H5OH (liquid)
combustion equation: C2H5OH + 3O2 = 2CO2 + 3H2O
enthalpy change for combustion (energy released during combustion): 1408.4 kJ/mol
OCTANE (chief constituent of gasoline): C8H18 (liquid)
combustion equation: C8H18 + 12.5O2 = 8CO2 + 9H2O
enthalpy change for combustion: 5508.9 kJ/mol
At first, it seems obvious that octane is more efficient per mole (to get the same amount of energy you must burn 3.91 times as many moles of ethanol), but that's not all there is to it. We have to worry about volume! While octane is more efficient per mole, it takes up more space per mole, so perhaps ethanol is at least more efficient per litre?
ETHANOL
density: 0.79g/mL
molar mass: 46.07 g/mol
using enthalpy change and the above constants we can calculate energy density: 24.2 kJ/mL
OCTANE
density: 0.70g/mL
molr mass: 114.22/mol
energy density = 33.76 kJ/mL
So octane is STILL more efficient! When you divide the octane's energy density by that of ethanol you find that it is approximately 1.4 times more energy dense, meaning that if you wanted to get the same amount of energy out of a tank of pure ethanol, your tank would have to be 1.4 times bigger!
Let's look at this a little more in depth. The average gas tank on a mid-sized car is about 70L (mine is 72). Using the above ratio, a tank of PURE ETHANOL would have to be 1.4 times bigger to last as long, making it about 97.97 L. Again, using the chemical constants, we can see that this is equal to about 1680 moles of pure ethanol (.
Ethanol is derived from ethanol fermentation fermentation, which is the same for all organisms that use it (most commonly, yeasts). Fermentation has the formula:
C6H12O6 (glucose) = 2C2H5OH + 2CO2 + 2ATP (adenosine triphosphate, the "energy carrying molecule")
So, in order to produce one tank of gas (1680 moles of ethanol), we would need half as many moles of glucose, or 840 moles. Since glucose has a molar mass of 180.16 g/mol, this means that to produce one tank of pure ethanol we would need around 151.3 kg of glucose.
One of the chief ways the Canadian government has proposed to get all this new ethanol is to use corn. Since most corn has a sugar (not just glucose!) content of about 9-16 percent, this means that at BEST, assuming that all sugar in corn is glucose (which it isn't) and that all plants are at max sugar content (which they aren't), we would need at least 945.84 kg of corn to produce one tank of pure ethanol. That is almost equal to a metric ton of corn!
Also, since carbon dioxide is produced in burning AND making the ethanol, its total production of carbon dioxide is 4 moles of carbon dioxide per one mole of ethanol. Since one must burn 3.91 moles of ethanol to get the same amount of energy as produced by one mole of octane, this means that the total carbon dioxide output of ethanol is 15.64 moles of carbon dioxidecompared to octane's 8 when producing the same amount of energy.
This of course is neglecting carbon dioxide produced in maintaining facilities for either process, extraction, distillation, and peripheral carbon production of both industries.
But still! Ethanol produces 1.96 times as much carbon per unit energy as octane does! This means that ethanol is actually a far worse fuel than octane, when judged solely on carbon production and efficiency.
Not only that, but the production process for ethanol using corn, switchgrass, and wood was found to be retardedly inefficient, having a negative nergy output (production using corn was found to require 29% more energy than it produced, switchgrass required 50% more, and wood required 57% more).
Looks like once again the conservative government has its collective head up its ass! Maybe if any of them had taken chemistry calsses in high school they would be able to make better environmental decisions.
User Reviews
Submitted by JonnyX (user info) at 2006-07-12 18:13:48 EDT (#)
Ranking: -2
Submitted by Bizdorph (user info) at 2006-07-10 19:44:47 (#)
Ranking: 0
SO, final result: ethanol is cheaper to produce, money-wise.
Thanks to JonnyX for calling me out on the financial side.
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any time, sport.
Submitted by Tracer0351 (user info) at 2006-07-11 14:26:19 EDT (#)
Ranking: 0
So hookhand, what your saying is, we need to mine corn fields too?
Submitted by STIXS (user info) at 2006-07-11 09:54:09 EDT (#)
Ranking: 1
You might want to go back and check some more facts, there, guy.
Submitted by skrapmetal (user info) at 2006-07-11 07:02:39 EDT (#)
Ranking: 0
I'm 100% for the widespread availability and use of E85 fuel in North America. I doubt it will be any cheaper than gasoline in the overall sence, for though it will cost less per gallon, it will take more gallons to drive the same distance since E85 has less chemical potential energy to be converted to heat than does gasoline. There will be plain old gasoline available most places for us guys with old-school carbureted or pre-E85 fuel-injected engines in our vehicles, produced with oil from the US and Canada's oil reserves. The alcohol can come from fermentation of corn and sugar beets grown in North America. It is a good economic decision as well as a good pollution decision. I'll vote for it.
Submitted by Jorge_Burrito (user info) at 2006-07-11 01:21:20 EDT (#)
Ranking: -2
Wow I had to register just to educate you retards...
You may know a little about chemistry, (although from your post I would say not much) but you know nothing about biology apparently.
Photosynthesis, the way plants create energy (aka sugar), involves reacting carbon dioxide and water together:
6H2O + 6CO2 ----------> C6H12O6 + 6O2
The idea is the CO2 released from combustion gets removed from the atmosphere through the continued growth of more corn. This is why ethanol is referred to as a zero carbon energy source, although this is not a perfect process and there is a small net release of CO2 and more problematic CO. At any rate it is much better then fossilized fuels. Next time try not reading information provided by oil companies.
Oh and since this is my first rating...
-2 DIE !!!
Submitted by Dolson (user info) at 2006-07-10 20:22:08 EDT (#)
Ranking: 0
Stephen Harper? Don't you mean Commander Data?
Submitted by Hookhand (user info) at 2006-07-10 19:54:45 EDT (#)
Ranking: -2
Ehtanol is a temporary fix to dillute the amount of foreign oil we need since cars can run on nearly 90% ethanol. We have the corn. It may take a lot of corn to make a tank of E85, but no one's running over roadside bombs in Baghdad to protect our foreign corn interests. In fact, we have so much corn subsidized, we are paying farmers not to grow it.
Biodiesel seems like the future of fuels, but until the Unites States and Canada decide to elect leaders who aren't in Big Oil's pocket and will fund biodiesel research, we need to use as little oil as possible, especially with the Chinese starting to drive. We don't just need oil for gasoline, we use oil for nearly everything, and we need to use less of it IMMEDIATELY, which the use of Ethanol will allow us to do. You're missing the point.
Submitted by Bizdorph (user info) at 2006-07-10 19:44:47 EDT (#)
Ranking: 0
SO, final result: ethanol is cheaper to produce, money-wise, but is energy-negative and inefficient.
Thanks to JonnyX for calling me out on the financial side. I never took that into consideration. leave it to the British!
Submitted by JonnyX (user info) at 2006-07-10 19:39:24 EDT (#)
Ranking: 0
also, don't forget, we're talking E85 fuel, which is 15% petrol, 85 ethanol - also don't forget E85 fuel has a higher octane rating (about 100-105) than a gallon of gasoline.
It doesn't really matter anyways, America is going E85, so guess what kind of cars those factories in Windsor and St. Catherines are going to be building??
Submitted by JonnyX (user info) at 2006-07-10 19:29:42 EDT (#)
Ranking: 0
Submitted by Bizdorph (user info) at 2006-07-10 19:02:43 (#)
Ranking: 0
Whoops. Mistake. my logic was backwards on that last reply. YOu're right. I get an F in economics.
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but you DO get an A in Political Science...doesn't Mr. Linzy teach that class??
Submitted by JonnyX (user info) at 2006-07-10 19:27:51 EDT (#)
Ranking: -2
Submitted by Bizdorph (user info) at 2006-07-10 19:02:06 (#)
Ranking: 0
In 2004/2005 a bushel of corn (approximately equal to 25 kg) cost roughly 3 dollars US.
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Actually, that's incorrect - what you are forgetting to mention is that the Canadian government is currently imposing a tariff of $1.65 per bushel on American corn imports
http://www.bloomberg.com/apps/news?pid=71000001&refer=canada&sid=aK4EAd.naR5U
So, if market forces were called into play - the true price of corn would be a lot lower.
Current American corn prices are at approx. $1.65/bu, although hot weather forecasts are driving the futures market up for the summer.
Submitted by Jack_McCallum (user info) at 2006-07-10 19:17:37 EDT (#)
Ranking: 0
Submitted by domenad (user info) at 2006-07-10 18:46:25 (#)
Ranking: 0
Didn't you lucky pricks just find a few trillion in oil sands?
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True, but without a few hundred thousand illegal Mexicans to process that tar by hand they have to create new technology to do the work.
Submitted by mockidol (user info) at 2006-07-10 19:10:48 EDT (#)
Ranking: 0
the fuel source is being used beacuse we can always grow more corn
oil is slowly running out.
Submitted by BigD (user info) at 2006-07-10 19:04:15 EDT (#)
Ranking: 1
Then why is this fuel source being used in the first place?
Submitted by Bizdorph (user info) at 2006-07-10 19:03:41 EDT (#)
Ranking: 0
THe problem, though, is that ethanol is supposed to be touted as a more environmentally friendly option, which could not be farther from the truth.
Submitted by Bizdorph (user info) at 2006-07-10 19:02:43 EDT (#)
Ranking: 0
Whoops. Mistake. my logic was backwards on that last reply. YOu're right. I get an F in economics.
Sorry.
Submitted by Bizdorph (user info) at 2006-07-10 19:02:06 EDT (#)
Ranking: 0
In 2004/2005 a bushel of corn (approximately equal to 25 kg) cost roughly 3 dollars US.
945.84/25 x $3 = about 113 dollars for a full tank of ethanol. Since a barrel of oil costs what..60 or 70 now?...and a small fraction of it is used for gasoline, it seems to me like the corn option is actually more expensive.
Submitted by JonnyX (user info) at 2006-07-10 18:55:40 EDT (#)
Ranking: -2
we would need at least 945.84 kg of corn to produce one tank of pure ethanol. That is almost equal to a metric ton of corn!
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uh-huh, that's right, now compare the price of a ton of corn versus a barrel of oil.
That's OK, I'll wait right here.....
Ding!
Time's up, here's your Uber Report Card:
CHEMISTRY = A
ECONOMICS = F
That gives you a -2.00 GPA, way to blow $7800 on tuition, assmunch...
Submitted by marginwalker (user info) at 2006-07-10 18:53:09 EDT (#)
Ranking: 2
Good post - I enjoyed reading it.
As far as Harper though - I got dibs on the mofo
Submitted by Axolotl (user info) at 2006-07-10 18:52:56 EDT (#)
Ranking: 2
Shit...I actually UNDERSTAND this!
Submitted by mles76 (user info) at 2006-07-10 18:50:57 EDT (#)
Ranking: 2
Etha-what? Yall Speak good eh?
Submitted by domenad (user info) at 2006-07-10 18:46:25 EDT (#)
Ranking: 0
You realize that because ethanol is ultimately synthesized from airborne CO2, that's the reason why they want to use it? Because it has a lower net carbon production? Also, ethanol engines just have higher compression ratios than octane fuels, so while they have less per-unit power, they still have the same output in an engine. I would think its rather moot though. Didn't you lucky pricks just find a few trillion in oil sands?
Submitted by BobLobla (user info) at 2006-07-10 18:45:08 EDT (#)
Ranking: 2
Unfortunately, nobody in the Canadian government seems to have taken chemistry class, because the products of the combustion of any hydrocarbon, alcohols included, are WATER AND CARBON DIOXIDE. WHen gasoline is burned, it produces WATER AND CARBON DIOXIDE. Also, when ethanol is burned, it produces WATER AND CARBON DIOXIDE.
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you could use a chemistry lesson though, these are not the only two things produces, there is also alot of carbon MONOXIDE.
Submitted by BobLobla (user info) at 2006-07-10 18:41:42 EDT (#)
Ranking: 2
A well done post.
I still like harper better than martin...
Submitted by Bizdorph (user info) at 2006-07-10 18:32:51 EDT (#)
Ranking: 0
For hte study, just search "corn production canada" on Google and click the PDF link seventh from the top.
Submitted by Bizdorph (user info) at 2006-07-10 18:31:50 EDT (#)
Ranking: 0
sources:
corn info: Sweet corn genotypes, by Agriculture and agri-food canada. http://res2.agr.ca/stjean/pdf/2004_11_FsMais_e.pdf
chemical data: General Chemistry eighth edition by Darrell D. Ebbing and Steven D. Gammon (2005, Houghton Mifflin)
efficiency of producing ethanol from corn/switchgrass/wood: Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower, by David Pimentel1 and Tad W. Patzek. Natural Resources Research. Issue: Volume 14, Number 1 Date: March 2005 Pages: 65 - 76 . Abstract at
http://www.springerlink.com/egfnjf45rfuvllflvaosadyg)/app/home/contribution.asp?
referrer=parent&backto=issue,6,6;journal,5,49;linkingpublicationresults,1:105547,1
calculation methods: yours truly