Scouseflyer From United Kingdom, joined Apr 2006, 2748 posts, RR: 6 Reply 2, posted (1 year 4 months 1 week 6 days 23 hours ago) and read 1363 times:
Both Methonal (CH3OH) and Ethanol (C2H5OH) can be made from organic matter, crops, foodwaste, sawdust, CO2 from the air and even human sewage!
How practial would it be to make jet engines that ran on Methoanl or a number of fuels.
A good comparison would be the Lotus Exige TriFuel demonstrator (http://www.grouplotus.com/engineering/green_technology.html ) that adjusts it'self based on whatever fuel it finds in the tank.
Burner71 From United States, joined Oct 2007, 42 posts, RR: 0 Reply 3, posted (1 year 4 months 1 week 6 days 23 hours ago) and read 1354 times:
Petrosun in southeast Texas has quite a few 10 acre ponds currently growing algae for the purpose of oil extraction for jet fuel. Operations began on April 1st.
DL767captain From United States, joined Mar 2007, 1723 posts, RR: 0 Reply 4, posted (1 year 4 months 1 week 6 days 22 hours ago) and read 1320 times:
Quoting Burner71 (Reply 3): Petrosun in southeast Texas has quite a few 10 acre ponds currently growing algae for the purpose of oil extraction for jet fuel. Operations began on April 1st.
From what i've heard this is the most promising to replace jet fuel. It's easy to grow and in the US all it needs is sunlight so it can be grown in the desert where there are vast amounts of land so all our production could be domestic with no import need.
Gsosbee From United States, joined Jan 2005, 825 posts, RR: 1 Reply 5, posted (1 year 4 months 1 week 6 days 21 hours ago) and read 1255 times:
I am involved in an algae effort, and it does appear that as of now this is the most advanced of the replacement fuel efforts. The refined product will we certifiable as a kero replacement.
One of the benefits of the algae approach is that there is virtually no waste. Even the solid waste product from the process can be sold as livestock feed.
Ikramerica From United States, joined May 2005, 18485 posts, RR: 60 Reply 6, posted (1 year 4 months 1 week 6 days 20 hours ago) and read 1202 times:
Quoting DL767captain (Reply 4): From what i've heard this is the most promising to replace jet fuel. It's easy to grow and in the US all it needs is sunlight
Quoting Gsosbee (Reply 5): I am involved in an algae effort, and it does appear that as of now this is the most advanced of the replacement fuel efforts. The refined product will we certifiable as a kero replacement.
Doesn't this use a lot of water? Water is going to be scarcer than fuel in the future, and so many of these new fuel technologies require massive amounts of water to produce.
Of all the things to worry about... the Wookie has no pants.
Widebodyphotog From United States, joined Jun 1999, 916 posts, RR: 67 Reply 7, posted (1 year 4 months 1 week 6 days 20 hours ago) and read 1189 times:
Quoting Scouseflyer (Reply 2): Both Methonal (CH3OH) and Ethanol (C2H5OH) can be made from organic matter, crops, foodwaste, sawdust, CO2 from the air and even human sewage!
How practial would it be to make jet engines that ran on Methoanl or a number of fuels.
Ethanol has about 76,000 BTU/USG while Jet fuel has over 125,000 BTU/USG. You would have to burn 64% more ethanol to get the same amount of energy as the same volume of Jet fuel.
Ethanol burns well and has a low freezing point but the effect would be the same as what it is doing to our cars which is lowering fuel efficiency. Besides that with current technology it takes about 130,000 BTU of energy to produce one gallon of Ethanol. Putting it in in our airplanes would be quite a wasteful proposition.
For jet airplanes energy density is everything when it comes to fuel. Future fuels need to combine high energy content with ease of extraction/refinement, and lower emissions. There is not anything on the horizon that even comes close to what we have today in Jet A.
Quoting Ikramerica (Reply 1): Nothing will replace it any time soon. The efforts are all for show.
OldAeroGuy From United States, joined Dec 2004, 2819 posts, RR: 61 Reply 8, posted (1 year 4 months 1 week 6 days 20 hours ago) and read 1186 times:
Quoting DL767captain (Reply 4): From what i've heard this is the most promising to replace jet fuel. It's easy to grow and in the US all it needs is sunlight so it can be grown in the desert where there are vast amounts of land so all our production could be domestic with no import need.
If you're looking for pond scum, Washington DC would be a better starting point.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
TristarSteve From Sweden, joined Nov 2005, 2838 posts, RR: 23 Reply 9, posted (1 year 4 months 1 week 6 days 19 hours ago) and read 1178 times:
The problem with ethanol is that it freezes at about M5degC. In Sweden there are a lot of cars running on E85 which is 85pc ethanol and 15pc petrol. The earlier models had problems starting in the winter. All these cars have block heaters, and the later models have induction heaters to overcome the problem. Although it works well in Brazilian crop dusters, it has no chance in commercial aviation.
Algae seems to be the best bet at present. It can grow fast in sewage works ouflow tanks, but is expensive to refine. Even at the present prices of kerosene it is priced out of the market. But as fuel prices rise it should become economical.
Gas to kerosene is promising in areas that have loads of gas, like Qatar that is building a plant.
Coal to kerosene works and SASOL in South Africa already have approval for 50pc use in commercial aircraft, and are near 100pc approval.
Oils from nuts and rape work but never in commercial quantities.
Look in the Flight Global archives. There was an excellent summary in the paper Flight a couple of months ago.
Widebodyphotog From United States, joined Jun 1999, 916 posts, RR: 67 Reply 10, posted (1 year 4 months 1 week 6 days 19 hours ago) and read 1172 times:
Quoting DL767captain (Reply 4): From what i've heard this is the most promising to replace jet fuel. It's easy to grow and in the US all it needs is sunlight so it can be grown in the desert where there are vast amounts of land so all our production could be domestic with no import need.
Actually it needs lots of CO2 to produce a high yields of oil and the arid desert is not the best place to produce algae at all. However algae is a promising feed stock for producing bio-derived fuel because it has no use as a human source of food, yields a higher amount of oil per unit of mass than corn, and has a high growth rate. It has some merits, but for a wholesale replacement of aviation fuel it would have to be produced in unbelievably vast amounts. Algae has some merits but is impractical at best.
Right now it takes about 3 times the amount of energy to produce an amount bio fuel having equivalent energy to a given mass of fossil fuel. And you have to use fossil fuels to make the energy to produce bio fuels... IMO growing fuel is a wholly unsustainable process. We are probably better off trying to increase the energy efficiency of the fuels we already use. An IC engine for example turns less than 25% of the energy in the fuel it burns into useful work. That to me says that there is a lot of room for improvement in fossil fuel technology.
PITIngres From United States, joined Dec 2007, 343 posts, RR: 5 Reply 11, posted (1 year 4 months 1 week 6 days 18 hours ago) and read 1139 times:
The small alcohols (methanol, ethanol) have lower volumetric energy density than kerosene, so you need larger tanks. Also, they are corrosive compared to kerosene (just as water is), so you would have to reengineer seals and materials all over the place. Larger alcohols aren't any easier to make than aliphatic hydrocarbons, and the oxygen in them doesn't do squat for energy production.
I would imagine that the combustors in modern engines are very finely tuned to the properties of current jet fuels, and shifting fuel properties might mean a redesign of the combustors. What you really want is some sort of non-fossil kerosene equivalent, not alcohols.
Most (all?) of the present day schemes for non-fossil synthetics use more energy overall than they save. Unless your energy source is non-fossil-fuel, you're not saving anything. I suspect that unless fusion can be tamed, ultimately we'll be looking at solar power satellites, or covering a few hundred square miles of desert with solar cells. The resulting electricity can be used for (energy-wasteful) production of "stuff", which could include kerosenes.
(Fission electricity needs to be part of the picture, too, but I suspect it will be aimed more at relieving power grid needs, rather than being part of a giant desert-destructo synthesis plant. Wind, hydro, geothermal are good local sources, but they total a very very small part of the overall supply.)
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