Biofuel takes flight with Virgin Atlantic
02-25-2008, 07:54 PM
#11
Gets Weekends Off
Joined APC: Dec 2005
Posts: 845
Biodiesel isn't that bad. In a vehicle it just requires a newer model. The main reason being that bio-diesel requires earlier combustion phasing for peak efficiency. So you need a modern on-board computer to make the changes. Kinda like how new vehicles can run premium or down to 87 octane.
In a jet engine these issues don't really matter. Biodiesel makes 67% less hydrocarbons than regular diesel which is a HUGE plus, however it does create more NOX which in airplanes I think is the biggest issue. At altitude the sun reacts with NOx causing a chain reaction that produces O3(ozone) which causes birth defects, respiration issues, and (I'm not 100% on this) I think it even kills the immune system. I have no clue if putting O3 out at higher altitudes is a good or a bad thing. They are always complaining about the ozone layer so perhaps in the upper altitudes it helps.
Diesel has on average= 129,500 btu/gal and a density of .85g/cm3
B100(100% biodiesel)= 118,296 btu/gal with a density of .88g/cm3 (8.65% less power producing ability while weighing 3.53% more than conventional No. 2 diesel)
B20 = 127,259btu/gal @ .856g/cm (1.73% less power producing ability while weighing only .7% more)
There's also a B2 blend but there's no point in it. 1-2% could barely be noticed if at all. In automotive diesel there can be a 15% variance in the btu/gal depending on the manufacturer and time of season. When I lived on the Mexican border I'd fill up over there for half the price and get 23mpg going 80mph in a 4dr Dodge diesel :O
It will be interesting to see what data they manage to produce from the test. I'd like to see a comparison of the reduction in hydrocarbons vs the reduction in fuel economy. If we get a 5-10%+ reduction in hydrocarbons with only a 1-2% loss in fuel economy that would be incredible.
In a jet engine these issues don't really matter. Biodiesel makes 67% less hydrocarbons than regular diesel which is a HUGE plus, however it does create more NOX which in airplanes I think is the biggest issue. At altitude the sun reacts with NOx causing a chain reaction that produces O3(ozone) which causes birth defects, respiration issues, and (I'm not 100% on this) I think it even kills the immune system. I have no clue if putting O3 out at higher altitudes is a good or a bad thing. They are always complaining about the ozone layer so perhaps in the upper altitudes it helps.
Diesel has on average= 129,500 btu/gal and a density of .85g/cm3
B100(100% biodiesel)= 118,296 btu/gal with a density of .88g/cm3 (8.65% less power producing ability while weighing 3.53% more than conventional No. 2 diesel)
B20 = 127,259btu/gal @ .856g/cm (1.73% less power producing ability while weighing only .7% more)
There's also a B2 blend but there's no point in it. 1-2% could barely be noticed if at all. In automotive diesel there can be a 15% variance in the btu/gal depending on the manufacturer and time of season. When I lived on the Mexican border I'd fill up over there for half the price and get 23mpg going 80mph in a 4dr Dodge diesel :O
It will be interesting to see what data they manage to produce from the test. I'd like to see a comparison of the reduction in hydrocarbons vs the reduction in fuel economy. If we get a 5-10%+ reduction in hydrocarbons with only a 1-2% loss in fuel economy that would be incredible.
02-25-2008, 07:56 PM
#12
Che Guevara
Joined APC: Aug 2005
Posts: 6,408
Either you've followed up on me or you made one hella guess. I was a student of his. On a side note my family farms and we've sold to BD plants. I've talked with the guys there a few times and had them take me through the process. There are also other huge bonuses from these plants. The byproducts can be used to feed cattle, help make foundations, and so on.
Also he has a son and someone needs to take a branch off a tree and keep whipping him till there's no more branches left. Last I remember of him anyway. Been a few years.
Also he has a son and someone needs to take a branch off a tree and keep whipping him till there's no more branches left. Last I remember of him anyway. Been a few years.
Last edited by ToiletDuck; 02-25-2008 at 08:01 PM.
02-25-2008, 08:34 PM
#14
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Joined APC: Mar 2007
Position: Sabre 60
Posts: 203
Which is the exact reason why we should be turning away from oil for our energy needs. Solar power, wind power, hydro power, nuclear power, biodiesel, whatever...
I personally agree with rickair. The cost to farm, produce, and transport biodiesel probably offsets all the environmentally friendly aspects of using biodiesel. I think we have a better chance of switching to alternative energy for our other energy needs (cars especially). I think kerosene is going to be powering airplanes for a long time.
It is good to know there are subsidies that make biodiesel less expensive, as well as carbon regulations to make oil consuming more expensive. The free market is great in many applications, but with something as critical to our nations survival as energy, we need someone to intervene (even if it is the government).
I personally agree with rickair. The cost to farm, produce, and transport biodiesel probably offsets all the environmentally friendly aspects of using biodiesel. I think we have a better chance of switching to alternative energy for our other energy needs (cars especially). I think kerosene is going to be powering airplanes for a long time.
It is good to know there are subsidies that make biodiesel less expensive, as well as carbon regulations to make oil consuming more expensive. The free market is great in many applications, but with something as critical to our nations survival as energy, we need someone to intervene (even if it is the government).
02-25-2008, 09:01 PM
#15
Che Guevara
Joined APC: Aug 2005
Posts: 6,408
When we finally start using up all our own waste we can then start going out into the "Great Pacific Garbage Patch" and get all we need from there.
Last edited by ToiletDuck; 02-25-2008 at 09:08 PM.
02-25-2008, 10:16 PM
#16
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Thread Starter
Joined APC: Dec 2007
Position: Fixed wing, left
Posts: 434
Completely untrue. Everyone and their mother seems to think that the only way to get these fuels is to farm, produce, and transport them. Completely false. 60% of human waste can be converted. Something that we are already making long before alternatives came along. From old candy, human feces, cooking oils, thrown away furniture, and even plastic. 60%-80% of landfills can be converted. Think of it as a byproduct to human living. We're going to create it regardless so we might as well convert it. They already do it in Japan at some places and in the US, Texas and Tennessee. We just need to implement it on a larger scale. Plug the plant into a nuclear reactor and we've got a clean solution.
When we finally start using up all our own waste we can then start going out into the "Great Pacific Garbage Patch" and get all we need from there.
When we finally start using up all our own waste we can then start going out into the "Great Pacific Garbage Patch" and get all we need from there.
Whats the cost to process that compared to refining dino bones or corn?
02-26-2008, 08:36 AM
#17
Feeling blessed.
Joined APC: Feb 2005
Position: Was I finally in the right place at the right time?
Posts: 540
Has anyone suggested to Sir Richard that a 4 engine jet uses quite a bit more fuel than a two engine jet?
Another point. Biodiesel may be the better choice, but it's necessarily the best choice. It holds water much like ethanol and therefore needs an anti-ice agent in the fuel. You can ask Speedishuttle in HI, particularly Maui. They used BD for a while and cause havoc with their Mercedes/Dodge vans.
Another point. Biodiesel may be the better choice, but it's necessarily the best choice. It holds water much like ethanol and therefore needs an anti-ice agent in the fuel. You can ask Speedishuttle in HI, particularly Maui. They used BD for a while and cause havoc with their Mercedes/Dodge vans.
02-26-2008, 12:07 PM
#18
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Joined APC: Apr 2007
Posts: 4,657
My guess is that safety not fuel efficiency was the issue. Much better to risk 25% of your engines that 50% if something doesn't work out as planned. Also I don't know much about the 747 fuel system. Would it be pretty easy to isolate the fuel for one engine from the other three?
02-26-2008, 12:15 PM
#19
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Joined APC: Nov 2005
Posts: 1,425
Originally Posted by Clue32
I would rather give money to American farmers than rich Saudi princes.
We won't ever be able to get away from them unless you make your own ethanol or biodiesel at home.
02-26-2008, 12:33 PM
#20
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Joined APC: Feb 2008
Position: retired
Posts: 645
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