Fuels like diesel, gasoline, hydrogen need to be mixed with air for an oxygen source to take place.
Posted on 01/03/2014 12:25:45 PM PST by thackney
Energy density and the cost, weight, and size of onboard energy storage are important characteristics of fuels for transportation. Fuels that require large, heavy, or expensive storage can reduce the space available to convey people and freight, weigh down a vehicle (making it operate less efficiently), or make it too costly to operate, even after taking account of cheaper fuels. Compared to gasoline and diesel, other options may have more energy per unit weight, but none have more energy per unit volume. On an equivalent energy basis, motor gasoline (which contains up to 10% ethanol) was estimated to account for 99% of light-duty vehicle fuel consumption in 2012. Over half of the remaining 1% was from diesel; all other fuels combined for less than half of 1%. The widespread use of these fuels is largely explained by their energy density and ease of onboard storage, as no other fuels provide more energy within a given unit of volume. The chart above compares energy densities (both per unit volume and per unit weight) for several transportation fuels that are available throughout the United States. The data points represent the energy content per unit volume or weight of the fuels themselves, not including the storage tanks or other equipment that the fuels require. For instance, compressed fuels require heavy storage tanks, while cooled fuels require equipment to maintain low temperatures. Beyond gasoline and diesel, other fuels like compressed propane, ethanol, and methanol offer energy densities per unit volume that are less than gasoline and diesel, and energy densities per unit weight that are less than or equal to that of gasoline. Natural gas, either in liquefied form (LNG) or compressed (CNG), are lighter than gasoline but again have lower densities per unit volume. The same is true for hydrogen fuels, which must be either cooled (down to -253oC) or compressed (to 3,000 to 10,000 psi). However, considering only energy density leaves out the relative fuel economies associated with vehicles capable of using other fuels. The typical fuel economy of an internal combustion engine in a light-duty vehicle is around 25 miles per gallon. On an equivalent basis, electric vehicles with fuel cells powered by hydrogen can double the fuel economy of a similarly sized gasoline vehicle, while battery-powered electric vehicles can achieve a quadrupling of fuel economy, but the costs of fuel cells, hydrogen storage, and batteries are prohibitively expensive to most consumers and the availability of refueling and charging facilities is extremely limited. In addition, the improvement in fuel economy of these vehicles does not compensate for the lower fuel densities of hydrogen and various battery types like lithium ion, lithium polymer, and nickel-metal hydride batteries that result in limited driving range relative to gasoline-powered vehicles.
I think that would be limited to longer chain hydrocarbons. #6 Fuel Oil (bunker fuel) will have a greater energy density.
Because when it comes to lifting, energy per pound is more important than energy per gallon. Hydrogen one of the best at the first and one of the worst at the second.
Fuels like diesel, gasoline, hydrogen need to be mixed with air for an oxygen source to take place.
Using this as the criteria, diesel would be best.
...............
Someone on one of these forums was telling me that the light sweet crude produced by most shale oil formations in the USA does not produce as nearly as much diesel as the heavy crude from say Venezuela.
Is this true?
OK, thanks.
The energy density of gasoline exceeds that of black powder by several orders of magnitude, which is why fuel-air explosives are so devastating. Not sure about HE, though.
The first stage of the Saturn burned kerosene which has a similar energy density. I think the opted for hydrogen on the upper stages to reduce weight and the load on the first stage.
bookmark
Gasoline can make some pretty impressive booms if you do it right, but I won’t give the details here. You are correct about speed making the difference; high explosives don’t release much energy but they release it all nearly instantaneously.
U235/U238 makes a pretty dense submarine fuel.
Light oil has less BTUs per barrel than heavy oil. But heavy oil takes more energy to refine because more energy is consumed cracking those longer chain hydrocarbons into the more valuable transportation fuels like gasoline and diesel.
The API gravity at 60°F (15.6°C) for No. 2 diesel fuel is between 30 and 42.
http://www.chevronwithtechron.com/products/documents/Diesel_Fuel_Tech_Review.pdf
Page 5
So while very light oil, nearly gas condensate with API gravities in the 40s and above, that should be true, Bakken, West Texas Intermediate, Brent and the like are most valuable because they have the most gasoline/diesel type hydrocarbons.
Long answer to say no, not true.
“So why didn’t Saturn V burn liquid oxygen and diesel instead of liquid hydrogen?”
Cause hydrogen go boom?
It certainly makes some pretty impressive noise when it explodes in the cylinders of a Harley.
I'm guessing that being compressed to a few hundred psi before being ignited has something to do with it.
Fuel/Air Explosive (FAE)
http://www.fas.org/man/dod-101/sys/dumb/fae.htm
http://www.fas.org/man/dod-101/sys/dumb/faeanim.gif
> other options may have more energy per unit weight, but none have more energy per unit volume.
/bingo
Thanks thackney.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
