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Senior Member
Registered: 11-04-08
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quote: ... This is actually good for global vegitation, One greeny professor on the net, tried to explain it ...
I find this part interesting. Is it really true that the Gore camp is defending his high emissions of CO2 by asserting that more CO2 is good for vegetation? This might (or might not) even be true, but I'd be amazed if actually said it. |
Junior Member
Registered: 08-07-09
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Just a side note, the UN, EPA,and now Congress have declared CO2 to be a pollutant. The dictionary defines pollutant as a material unfit or harmful to living things. But we cannot exist without CO2, see a pattern here?
1.Rename CO2 a "pollutant"
2.Make up nonsense about how much CO2 is produced by whom using a questionable formula.
3. Impose a tax on the producers CO2.(everyone)
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Senior Member
Registered: 02-18-07
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You got it!
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Senior Member
Registered: 10-28-07
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quote: Forgive my ignorance, math is not my strong suit. How is it that you can get more out of the fuel than there is fuel? If there is only six tons of raw material, how do you end up with twenty tons of waste material?
2C10H22 + 31 O2 = 20 CO2 + 22 H2O CO2 weighs 44 grams per mole, while the fuel weighs 142 grams per mole. Thus, the above reaction will transform 284 grams of JetA (and 992 grams of oxygen) into 880 grams of CO2 and 396 grams of water vapour. |
Senior Member
Registered: 10-28-07
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Notice that 284+992 = 880+396.
Yes, the masses are rounded and there will be some minor mass loss with the energy released and the new bonds, but for all intents and purposes fuel + oxygen = exhaust products.
The only source of confusion is that the mass of the oxygen is never given, only the mass of the fuel and then the mass of the exhaust products.
The same "mystery" happens with just about any combustion because the mass of the oxygen gets overlooked. One science example is to burn steel wool. You weigh the steel wool first, then burn it. Then weigh the oxidized "ashes" and they weigh more. The Fe becomes either FeO or Fe2O3 and either way, the "ash" weighs more than the iron you started with.
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Senior Member
Registered: 11-04-08
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quote: Originally posted by willyger:
I probably wasn’t clear enough in my original post, for those who are biased and use the technique of trying to make facts fit a preexisting concept, as opposed to following the evidence wherever it leads.
Since no one mentioned CO, O3, or Nox, as emissions, they most likely have derived their answers from a method that uses a certain lab apparatus to heat a hydrocarbon , applies pure oxygen , and runs it through 2 filters which measure CO2only, and H2Oonly, and exhausting unused oxygen. They could have used a model airplane engine and obtained a result closer to reality.
This was my analogy to using the coefficient of friction equation to predict how fast a dragster could ever go in a ¼ mile, get it? They were wrong, and the above lab formula cannot possibly predict exactly what an air breathing engine will emit, when breathing atmospheric air, not pure oxygen.
The above lab experiment is using a controlled situation, using only oxygen, and a hydrocarbon, to predict the emissions output of an engine which breaths atmospheric air which is 79 % nitrogen and and contains hydrogen etc. and contains plenty of sulfur and other reactive chemicals especially near the 1500 active volcanoes on the planet , In fact , the state requires an emissions test for CO, O3 and Nox, also, I think engines burning hydrocarbons using atmospheric air will emit H2O2, CH20, C3H6O3, C20H28O2, H2SO4, HNO3, CO, ( CO is an emission used to commit suicide, so it must be an actual fact, get it?) .
So, maybe try explaining, according to the greenies why an AIR breathing engine only emits CO2 and H2O, and no CO, O3, CH2O, etc.
My original post was meant to help think up a small scale experiment to test a real engines CO2 output, because I seriously doubt the greenie version , which is based on a lab apparatus using pure oxygen
You really didn't read, did you? " The equations that have been shown, while they don't predict the exact composition of the exhaust, are very good at telling what the general mixture will be. The equations that would predict the exact nature would take more memory and data than your computer can handle. Even if you're working from a supercomputer, no computer on earth has the capabilities to do an exact calculation of anything you've asked so far. Generalities are all you're going to get. And smarti listed some of the common impurities in the exhaust. There are probably a few hundred others altogether, with likely a dozen or so stable molecules present." You aren't going to get a full analysis of all of the exhaust products. The "lab data" was an ideal case of actual jet engines, which are designed to burn as efficiently as possible. Efficient combustion means very low production of side products such as the nitrogen oxides, sulfur oxides, etc... Really, before accusing people of using bad equations, actually know what the equations apply to. They have been repeatedly declared to be idealistic. Is that not enough. No one here is willing to do a serious analysis ,which would probably cost thousands of dollars, of an actual jet engine. quote: The dictionary defines pollutant as a material unfit or harmful to living things. But we cannot exist without CO2, see a pattern here?
Well, you try living in even 15% CO2 and see how that works out for you. Yes, it is necessary for certain parts of life. However, so is iron. Do you really want to go around eating large amounts of iron? CO2 is a pollutant. However, while cutting emissions is good(for other reasons), it may not make sense to tax people. But that's beyond the scope of this thread. quote: 2.Make up nonsense about how much CO2 is produced by whom using a questionable formula.
You're the only one questioning it. The formula is IDEALISTIC. How many times must I repeat that? |
Senior Member
Registered: 10-02-08
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quote: Originally posted by willyger:
The claim has been bandied about in the news Media that a light jet produces about 40 tons of co2.(Al Gores private jet on a cross country flight)
Can you provide a link for this? I can't find any mention of 40 tons of CO2 anywhere on web. |
Senior Member
Registered: 11-12-04
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quote: Originally posted by willyger:
I probably wasn’t clear enough in my original post, for those who are biased and use the technique of trying to make facts fit a preexisting concept, as opposed to following the evidence wherever it leads.
Since no one mentioned CO, O3, or Nox, as emissions, they most likely have derived their answers from a method that uses a certain lab apparatus to heat a hydrocarbon , applies pure oxygen , and runs it through 2 filters which measure CO2only, and H2Oonly, and exhausting unused oxygen. They could have used a model airplane engine and obtained a result closer to reality.
This was my analogy to using the coefficient of friction equation to predict how fast a dragster could ever go in a ¼ mile, get it? They were wrong, and the above lab formula cannot possibly predict exactly what an air breathing engine will emit, when breathing atmospheric air, not pure oxygen.
The above lab experiment is using a controlled situation, using only oxygen, and a hydrocarbon, to predict the emissions output of an engine which breaths atmospheric air which is 79 % nitrogen and and contains hydrogen etc. and contains plenty of sulfur and other reactive chemicals especially near the 1500 active volcanoes on the planet , In fact , the state requires an emissions test for CO, O3 and Nox, also, I think engines burning hydrocarbons using atmospheric air will emit H2O2, CH20, C3H6O3, C20H28O2, H2SO4, HNO3, CO, ( CO is an emission used to commit suicide, so it must be an actual fact, get it?) .
So, maybe try explaining, according to the greenies why an AIR breathing engine only emits CO2 and H2O, and no CO, O3, CH2O, etc.
My original post was meant to help think up a small scale experiment to test a real engines CO2 output, because I seriously doubt the greenie version , which is based on a lab apparatus using pure oxygen
 Yes of course with the temperatures and air-fuel ratios there are NOX emissions, whatever sulfur is there comes out as oxides, etc. The OP was disputing how much CO2 a jet produces and maybe not all the carbon produces CO2. Turbines burn very lean. There is plenty of oxygen available to completely burn better than 99% of the carbon. I used to do the performance calculations, participated in emission tests, etc. NOX production is irrelevant when you are debating the CO2 production. Many of the more complex chemical products you believe are coming out of the engine are more likely produced by photochemical effects in the atmosphere after the jet is long gone. Whatever other constituents you might be able to the detect in the turbine exhaust, the vast majority of carbon is coming out as CO2. Be my guest if you want to quibble about a tiny fraction of a percent that isn't an "ideal" product of hydrocarbon combustion. |
Senior Member
Registered: 06-22-09
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quote: Originally posted by roofingguy:
The fact remains that which "light jet" wasn't specified.
An EMB-135LR holds about 12,000 pounds of fuel and will thus generate almost 40,000 pounds of CO2, so even that smallish jet is halfway to making the "40 tons" accurate.
I felt the need to interject a small factoid here - while the jet may hold that much fuel, the question was never raised about how long it would take to burn it. Google tells me that 313 gallons per hour is a reasonable burn rate for the EMB-135LR. Jet-A weighs 6.8 pounds per gallon, so that is about 4200 pounds per hour. The 12,000 gallons on board last for 6 hours, carrying 40 people roughly 2,200 miles. Google also tell me that your average car produces 24.1 pounds of CO2 per gallon used and I'll call an average mileage of 25 mpg. Yes I know there are cars that are better than 25 and there are many which are worse. So if I can fudge that a little, we can say that a car emits about a pound of CO2 for every mile it drives. Now we're going to drive those 40 people that 2,200 miles. If each one takes their own car, they're going to drive 88,000 miles and they will also produce 88,000 lbs of CO2. Kinda puts that 40,000 lbs number into a slightly different perspective doesn't it? Makes you wonder what else they might not have been entirely up front with you about, eh? |
Senior Member
Registered: 10-28-07
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quote: Kinda puts that 40,000 lbs number into a slightly different perspective doesn't it? Makes you wonder what else they might not have been entirely up front with you about, eh?
I was only evaluating whether the original claim was plausible, not whether it was meaningful.   quote: I probably wasn’t clear enough in my original post, for those who are biased and use the technique of trying to make facts fit a preexisting concept, as opposed to following the evidence wherever it leads.
Since no one mentioned CO, O3, or Nox, as emissions, they most likely have derived their answers from a method that uses a certain lab apparatus to heat a hydrocarbon , applies pure oxygen , and runs it through 2 filters which measure CO2only, and H2Oonly, and exhausting unused oxygen.
And yes, obviously I idealized the reaction -- and never claimed otherwise. Nothing was measured at all. But even with big bad cars the idealized reaction isn't that far off. If ALL the isooctane underwent complete combustion, then 1 gallon of gas (by the EPA numbers) produces 19.45 pounds of CO2. At 25MPG, that's 0.778 pounds per mile, or 353 grams per mile. What are the EPA Tier 1 limits for the major pollutants for passenger cars? THC: 0.41 g/mi NMHC: 0.25 g/mi NOx: 0.4 g/mi CO: 3.4 g/mi Particulate: 0.08 g/mi So the maximums in the exhaust are 4.54 grams per mile. This is a small proportion of the 353 grams of CO2 and 325 grams of H2O that "should" be produced at 25MPG. So only about 350 grams of CO2 are "really" produced per mile instead of 353. Or maybe only 340. So what? Rounding the answers off more than accounts for this (hence "about 12,000 pounds" and "about 40,000 pounds") and the net result is still accurate. |
Senior Member
Registered: 06-09-09
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FORTY TONS?? How can we allow this? After all, CO2 is a trace gas, only about 0.038% of the atmosphere is CO2. So that's what, 380 parts per million? Hardly any, so any increase is important, right? Do you all realize HOW MUCH IMPACT that much CO2 makes on that 380 ppm? Start with 0.038% of the atmosphere. OK. Now, theres 14.7 pounds of atmosphere per square inch, right? And there's 144 square inches in a square foot, right? So there's 2100+ pounds of air over every square foot. How many square feet in a square mile? A bit more than 26.2 million. (I'm just rounding out numbers here, but staying on the low side) Now we got 55,020,000,000 pounds of air over every square mile. Let's convert to tons, so we can get back to smaller numbers. Thats 27,510,000 tons. Per square mile. 27.5 million tons. Per. Square. Mile. So that 40 tons, that's NEARLY ONE AND A HALF MILLIONTH!! Added to that 380 parts per million we already got there. We're up to 381.5 ppm!! Woo hoo! The sky, she is a falling!! Oh, wait a minute. That's just for one square mile. Oops! Let's see, there are about 196,000,000 square miles of surface area for the Earth. So, take one and a half parts per million, divide by about two hundred million, and that 40 tons is 3/4 of a part per trillion. Yeah, I'm panicking now!! (sigh) Maybe I'll just go watch some TV and have a beer. Carbonated, you know. All those bubbles, that's CO2. Yeah, I'm Destroying The Planet Now!! Maybe, I'll have TWO beers!! hee hee! I'm so evil |
Senior Member
Registered: 10-28-07
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quote: I'm so evil
Well, if you want to do the math that way, you also need to consider that the U.S. airlines alone flew 1,072,417,541,000 passenger-miles in 2008. There are other countries with airlines as well. If you assume 250 passengers per plane and 48 pounds CO2 per mile (based on one source giving 22,000 pounds for a 454-mile flight with a 747), then the American airlines would have generated 205,904,167,872 pounds (102,952,084 tons). I wonder why choosing to see what impact 40 tons has seems rather negligible... "Gee... what impact will 0.00004% of the U.S. contribution have? Look! it's almost nothing!!!" |
Senior Member
Registered: 10-28-07
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Just for reference... yes, there's a LOT of CO2 in the atmosphere already... about 3x10^12 tons.
But when the calculated yearly increase from 1750 to 1960 is 1,190 million tons per year, the U.S. airlines alone (from the preceding rough back-of-the-envelope calculations) would thus account for 8.5% of the yearly increase.
Still insignificant?
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Senior Member
Registered: 06-09-09
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Well, first of all, I wasn't the one to raise an alarm over a single flight by a light jet. And I'll grant you, that one flight is only 40 out of 100 million tons. So, the actual impact of ALL flights is 2 1/2 million times the impact of that one flight. 2.5 million times 3/4 of a trillionth is... lets see..... almost one half of one thousandth? roofingguy, I usually agree with your posts, but on this.... Still not ready for panicking.  |
Senior Member
Registered: 06-22-09
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Hmmmm....I wonder how much CO2 comes from people breathing.
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Senior Member
Registered: 11-04-08
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quote: Originally posted by bflynn:
Hmmmm....I wonder how much CO2 comes from people breathing.
[Hyperventilates] I don't know. All of this talk about global warming is freekin' me out, man. |
Senior Member
Registered: 10-28-07
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quote: Originally posted by roofingguy: I was only evaluating whether the original claim was plausible, not whether it was meaningful.
I thought you'd at least point out that the "per year" average is just that... the arithmetic mean. Obviously the 1780-1781 change is NOT the same as the 2008-2009 change. This will put the 2008 aircraft production down to a much smaller percentage of the yearly production and not the 8.5% it mathematically worked out to. I didn't say I was ready for panicking either. But, I was at least trying to offer a bit of balance, before the Greenies came in and started ripping everything to shreds. |
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