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For SpaceNut .... The forum contains discussions along these lines, but there was no topic dedicated to this market...
https://finance.yahoo.com/news/clean-je … 00846.html
The article at the link above includes reporting on several ventures that are in early stages, as well as a few that have not done well.
Apparently investor interest in the goal is helping to pay for attempts to deliver high quality jet fuel without digging it up.
The link was contributed by FriendOfQuark1
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I don't know what the new "sustainable jet fuels" really are.
About 25 years ago I worked with biodiesel, which is more viscous than kerosene, physical properties resembling #2 diesel, which is too thick for gas turbines as currently built. It also freezes at about 29 F, when commercial Jet-A typically freezes near -58 F.
We could only blend it with kerosene. Typically 20 to 30% by volume biodiesel in Jet-A, which would then freeze somewhere around -10 to -15 F. I did make one blend with 30% biodiesel and about 0.5% ethyl tetra butyl ether (ETBE). That did not freeze even at -68 F, despite the plain Jet-A freezing at -58 F in tests I ran.
But that's not a fully sustainable fuel, only a fuel extender. It did not reduce emissions of NOx, but it did reduce carbon sooting quite a bit. You could smell the source of the biodiesel in the jet blast.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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What is Dimethyl Ether like in jet engines? It sounds like it's one of the easier synfuels to produce from water and CO2.
Use what is abundant and build to last
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Shell: Civil Jet Fuel
Jet A-1
Jet A-1 is a kerosine grade of fuel suitable for most turbine engined aircraft. It has a flash point minimum of 38 degrees C (100°F) and a freeze point maximum of -47 degrees C. It is widely available outside the U.S.A. The main specifications for Jet A-1 grade (see below) are the UK specification DEF STAN 91-91 (Jet A-1) Nato code F-35, (formerly DERD 2494) and the ASTM specification D1655 (Jet A-1).Jet A
Jet A is a kerosine grade fuel, normally only available in the U.S.A. It has the same flash point as Jet A-1 but a higher freeze point maximum (-40°C). It is supplied against the ASTM D1655 (Jet A) specification.Jet B
Jet B is a distillate covering the naphtha and kerosine fractions. It can be used as an alternative to Jet A-1 but because it is more difficult to handle (higher flammability), there is only significant demand in very cold climates where its better cold weather performance is important. ASTM have a specification for Jet B but in Canada it is supplied against the Canadian Specification CAN/CGSB 3.23TS-1
TS-1 is the main jet fuel grade available in Russian and CIS states. It is a kerosine type fuel with slightly higher volatility (flash point is 28C minimum) and lower freeze point (<-50C) compared to Jet A-1.
This means Jet A-1 freezes at -47°C (-52.6°F), while Jet A freezes at -40°C (-40°F), and Jet B freezes at -60°C (-76°F).
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For RobertDyck re #4
Thank you for the concise summary of jet fuels in current use.
For Terraformer ... Thank you for a helpful question!
I asked Google to try get the ball rolling, and it found a ** lot ** of citations... this one seems like a good starting point...
https://afdc.energy.gov/fuels/emerging-dme
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Biobutanol
Dimethyl Ether
Methanol
Renewable GasolineDimethyl Ether
Dimethyl ether (DME) is a synthetically produced alternative to diesel for use in specially designed compression ignition diesel engines. Under normal atmospheric conditions, DME is a colorless gas. It is used extensively in the chemical industry and as an aerosol propellant. Dimethyl ether requires about 75 pounds per square inch (psi) of pressure to be in liquid form. Because of this, DME's handling requirements are similar to those of propane—both must be kept in pressurized storage tanks at an ambient temperature.
The use of DME in vehicles requires a compression ignition engine with a fuel system specifically developed to operate on DME. A number of DME vehicle demonstrations have been held in Europe and North America, including one in which a customer operated 10 vehicles for 750,000 miles.
ProductionAlthough DME can be produced from biomass, methanol, and fossil fuels, the likely feedstock of choice for large-scale DME production in the United States is natural gas. DME can be produced directly from synthesis gas produced from natural gas, coal, or biomass. It can also be produced indirectly from methanol via a dehydration reaction. DME is not commercially available in the United States.
BenefitsDimethyl ether has several fuel properties that make it attractive for use in diesel engines. It has a very high cetane number, which is a measure of the fuel's ignitibility in compression ignition engines. The energy efficiency and power ratings of DME and diesel engines are virtually the same.
Because of its lack of carbon-to-carbon bonds, using DME as an alternative to diesel can virtually eliminate particulate emissions and potentially negate the need for costly diesel particulate filters. However, DME has half the energy density of diesel fuel, requiring a fuel tank twice as large as that needed for diesel.
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What I did not realize is that DME has to be carried in pressure tanks like propane. A detail is that the energy density is nearly half that of diesel fuel, so fuel tanks have to be twice as large for a given work load. However, there appear to be some definite advantages!
So far I haven't found anything that indicates the fuel can be used as jet fuel directly. It may need processing further to yield something suitable for jet engines.
We certainly appear to have an opportunity for members to contribute. If anyone has questions about the book I bought at Calliban's recommendation, I would be happy to try to find an answer.
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As often happens, NewMars members may not have time to read or view the original source material for a topic.
Here is a snippet from the original article ...
The investment values Twelve at more than $1 billion. It is one of several startups using a chemical process that mimics photosynthesis to produce jet fuel with far lower emissions than fossil fuels. They are raising significant amounts of cash in the midst of a rush of funding deals.
Last week, Brookfield Asset Management said it would invest more than $200 million into a company called Infinium that has a generally similar approach. Brookfield might put in up to $850 million more. A few years ago, Prometheus Fuels, a startup with a deal to sell fuel to American Airlines that has a comparable process, hit a $1 billion valuation. A competitor called HIF Global is also a unicorn after raking in investment.
Investors are shifting their bets in clean fuels to companies that use chemistry to turn carbon dioxide, water and renewable electricity into energy. Known as eFuels, synthetic fuels or power to liquids technologies, they offer the tantalizing possibility of producing limitless amounts if given enough cheap renewable power.
“This actually has a shot at eventually replacing fossil fuels,” said Zachary Bogue, co-managing partner at the venture-capital firm DCVC. It was one of Twelve’s first investors and is putting money in again in the new fundraising.
The point is that despite the difficulty of the undertaking, there are investors willing to place bets on this technology because the payoff would be massive at a planetary level.
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US Air Force (from 2010): Air Force scientists test, develop bio jet fuels
The A-10 was powered by a blend of conventional JP-8 and a biomass fuel derived from camelina, a nonfood rotation crop similar to soybean and mustard. The alternative fuels certification office is preparing to test fuels made primarily from plant oils and animal fats.
The Guardian (also 2010): Algae to solve the Pentagon's jet fuel problem
This item contained incorrect information supplied by the Defence Advanced Research Projects Agency (Darpa). We repeated its assertion that jet fuel production from refined algae would begin next year. Darpa now says that it should have told us that testing will begin next year with production not planned until 2013.
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Darpa's research projects have already extracted oil from algal ponds at a cost of $2 per gallon. It is now on track to begin large-scale refining of that oil into jet fuel, at a cost of less than $3 a gallon, according to Barbara McQuiston, special assistant for energy at Darpa. That could turn a promising technology into a market-ready one. Researchers have cracked the problem of turning pond scum and seaweed into fuel, but finding a cost-effective method of mass production could be a game-changer.
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McQuiston said a larger-scale refining operation, producing 50 million gallons a year, would come on line in 2011 and she was hopeful the costs would drop still further – ensuring that the algae-based fuel would be competitive with fossil fuels. She said the projects, run by private firms SAIC and General Atomics, expected to yield 1,000 gallons of oil per acre from the algal farm.
UK Air Force (14 August 2024): Jets powered by algae: The RAF's green revolution driven by sustainable fuel
For the first time, RAF Lossiemouth in Scotland, one of the UK's busiest air bases, has integrated a blend of conventional jet fuel with sustainable aviation fuel (SAF) into its routine operations, marking a significant step towards a more sustainable future.
Apart from algae, sustainable fuel sources also include hydrogenated fats and oils, wood waste, alcohols, sugars, household waste and biomass.
Between November 2023 and February 2024, the RAF received 4,000,000 litres of blended SAF through a contract with World Fuel Services, with an additional 5,150,000 litres scheduled for delivery from July to October 2024.
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In November 2022, an RAF Voyager made history as the first wide-bodied military aircraft to successfully fly using 100% SAF.
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