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| Re: subway under the ocean (1621448) | |||
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Re: subway under the ocean |
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Posted by Avid Reader on Sat Jun 17 12:24:25 2023, in response to Re: subway under the ocean, posted by The Silence on Fri Jun 16 22:17:45 2023. It's not that "jet fuel is bad" that is the key concern... it's that there's only so much oil to make it out of. One day that WILL run out. What are we going to do then? Production Jet fuel is a mixture of various hydrocarbons. The range of their sizes (molecular weights or carbon numbers) is restricted by the requirements for the product, for example, freezing point or smoke point. Jet fuels are sometimes classified as kerosene or naphtha-type. Kerosene-type fuels include Jet A, Jet A-1, JP-5 and JP-8. Naphtha-type jet fuels, sometimes referred to as "wide-cut" jet fuel, include Jet B and JP-4. "Drop-in" biofuels are biofuels that are completely interchangeable with conventional fuels. Deriving "drop-in" jet fuel from bio-based sources is ASTM approved via two routes. ASTM has also found it safe to blend in 50% SPK into regular jet fuels.[40][22] Only tests have been done so far with blending in synthetic paraffinic kerosene (SPK) in considerably higher concentrations.[41] HEFA-SPK Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosine (HEFA-SPK) is a specific type of hydrotreated vegetable oil fuel.[2] As of 2020 this was the only mature technology.[15][2] HEFA-SPK fuel is considered to be a leading alternative replacement for conventional jet fuel by the CAA.[42] HEFA-SPK was approved by Altair Engineering for use in 2011.[43] HEFA-SPK is produced by the deoxygenation and hydroprocessing of the feedstock fatty acids of algae, jatropha, and camelina.[44] Bio-SPK This fuel uses oil that is extracted from plant sources such as jatropha, algae, tallows, waste oils, babassu, and Camelina to produce synthetic paraffinic kerosene (bio-SPK) by cracking and hydroprocessing. Using algae to make jet fuel remains an emerging technology. Companies working on algae jet fuel include Solazyme, Honeywell UOP, Solena, Sapphire Energy, Imperium Renewables, and Aquaflow Bionomic Corporation. Universities working on algae jet fuel are Arizona State University and Cranfield University. Major investors for algae based SPK research are Boeing, Honeywell/UOP, Air New Zealand, Continental Airlines, Japan Airlines, and General Electric.[citation needed] FT-SPK Another route involves processing solid biomass using pyrolysis to produce oil or gasification to produce a syngas that is processed into FT SPK (Fischer–Tropsch Synthetic Paraffinic Kerosene).[citation needed] ATJ-SPK Alcohol-to-jet (ATJ) pathway takes alcohols such as ethanol or butanol and de-oxygenates and processes them into jet fuels.[45] Companies such as LanzaTech have created ATJ-SPK from CO2 in flue gases.[46] The ethanol is produced from CO in the flue gases using microbes such as Clostridium autoethanogenum. In 2016 LanzaTech demonstrated its technology at Pilot scale in NZ –using Industrial waste gases from the steel industry as a feedstock for its microbial fermentation.[47][48][49] Gevo developed technology to retrofit existing ethanol plants to produce isobutanol.[50] Alcohol-to-Jet Synthetic Paraffinic Kerosene (ATJ-SPK) is a proven pathway to deliver a bio-based, low-carbon option to travelers.[citation needed] Future production routes Systems that use synthetic biology to create hydro-carbons are under development. The SUN-to-LIQUID project is examining Fischer-Tropsch hydro-carbon fuels (solar kerosine) through the use of a solar reactor.[51][52][53] Alder Fuels raw material is waste from forestry and agriculture. This is mainly structural polymers cellulose, hemicellulose and lignin. They are processed via pyrolysis. The result is condensed into greencrude, a hydrocarbon-rich liquid, which is turned into fuel in refineries.[54] Piston engines Small piston engines can be modified to burn ethanol.[55] Swift Fuel, a biofuel alternative to avgas, was approved as a test fuel by ASTM International in December 2009.[56][57] Technical challenges Nitrile-based rubber materials expand in the presence of aromatic compounds found in conventional petroleum fuel. Pure biofuels that aren't mixed with petroleum and don't contain paraffin-based additives may cause rubber seals and hoses to shrink.[58] Synthetic rubber substitutes that are not adversely affected by biofuels, such as Viton, for seals and hoses are available.[59] The United States Air Force found harmful bacteria and fungi in their biofueled aircraft, and use pasteurization to disinfect t |
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