Safe Aviation Fuel Tanks

[rogers_buck]

Just saw the CNN program on Ft 800. The program left a bit of a shadow of danger hanging over airplanes in service concerning fuel tank explosions. The new nitrogen pressurization systems will be built into Boeing aircraft by 2008, but the existing fleet will be at risk.<br /><br />Does anyone know if you can carbonate jet fuel? Would that work for purging the fuel tanks of oxygen throughout the fligh?<br />

 

[vogon13]

It's been a long time since chemistry class . . . <br /><br />Does the polar or non-polar nature of the flud impact the solubility of gas?<br /><br />Water, a polar solvent, disolves mucho CO2, your aviation fuels, JP-4, etc., are hydrocarbon and non polar in nature.<br /><br />Don't know if CO2 dissolves readily in it or not. If it doesn't, perhaps another gas would.<br /><br /><br />Keep in mind, this idea does carry some other problems. Pressure buildup in sealed containers. Replenishment of the gas. Workers in fuel storage containers might suffocate. Foaming of the fuel as the ambient pressure decreases as the aircraft climbs to altitude.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[webtaz99]

They already put <b>anti-foaming</b> agents in jet fuel. <div class="Discussion_UserSignature"> </div>

 

[vogon13]

Enough to counteract a drastically more 'fizzy' fuel?<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[webtaz99]

All I know is that high pressure fuel pumps and injectors don't like bubbles. <div class="Discussion_UserSignature"> </div>

 

[vogon13]

Enough to counteract a drastically more 'fizzy' fuel ? ?<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[propforce]

<font color="yellow">Does anyone know if you can carbonate jet fuel? Would that work for purging the fuel tanks of oxygen throughout the fligh? </font><br /><br />The answer is not in "carbonating" the jet fuel. The problem is that there is a presence of *air* (hence 21% oxygen by volume) in the fuel tank.<br /><br />So the question is how to eliminate *air* in the fuel tank (the empty part)? The solution (I believe) is come up with a nitrogen *purging* system thus replacing the *air* in the fuel tank with *pure nitrogen*. <br /><br />The problem is adding high pressure nitrogen bottles in the aircraft compartment (how much depending on flight duration) and the high pressure GN2 goes through a "regulator" to drop the pressure to a suitable level for aircraft fuel tanks. <br /><br />Now as you know, there's not just a single fuel tank in an aircraft. The fuel is stored in the fuselage (belly) of aircraft as well as in its wings. So that means you'll need to route this GN2 pressure lines all over the aircraft to where the fuel tanks are. This takes time, effort and make room available. It becomes another "retrofit" job for every aircraft. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

If there is no Oxygen available there is no chance of fire. The only thing needed is using larger pumps to use bypass fuel to pressurize the tanks and a relatively small amount of Nitrogen to inert the tanks when they are not full. <div class="Discussion_UserSignature"> </div>

 

[josh_simonson]

Alternately some fuel could be burnt fuel-rich and the cooled exhaust used to purge the fuel tanks. That'd probably be lighter than a compressed nitrogen system.

 

[scottb50]

You would be putting Oxygen into the tanks, even fuel rich some would be left, not a good idea. <div class="Discussion_UserSignature"> </div>

 

[rogers_buck]

That's what they are doing for the new jets starting in 2008. But they aren't planning on doing anything for the existing fleet. The odds are too low, cheaper to just buy the dead.<br /><br />So the question I'm exploring is how you might treat the fuel to get it to purge the oxygen/air as the tank is drained. Granterd, you can treat the airplane, but the economics don't allow for that.<br /><br />Hypothetically, a fizzy fuel would purge air from the tank and replace it with inert CO2. CO2 is heavier than air and would tend to push the air out of a vent at the top of the tank. The supersaturated CO2/fuel soloution would stay in equilibrium as the fuel level dropped by releasing more CO2.<br /><br />But jet fuel isn't soda pop, and fuel pumps aren't soda jerks. I just wonder if there is a chance a simple scheme like this might work.<br />

 

[nacnud]

how about toping the tanks up with a cup of liquid nitrogen after every fill? As it reverts to gas it should displace the air. Thats how the draft flow beer cans are pressureised.

 

[barrykirk]

Or throwing some dry ice into the tanks?<br /><br />Since CO2 is heavier than air, would it form a layer in the tank seperating the fuel from the oxygen in the tank?<br /><br />It's not perfect, since turbulance can mix it up, but would it provide any more safety?

 

[nexium]

All those ideas have both advantages and disadvantages. My guess is do nothing is best. The wiring arc explanation is likely a cover up for one or more missiles that hit flight 800. The nitrogen on new planes will only slightly reduce the valnerbility of passenger planes to missle hits.<br />Another possibility is that the fuel in flight 800s tanks contained far more petroleum volitiles than the specs for the fuel. Neil

 

[bdewoody]

In all the years jet aircraft have been flying there has been only this one case where supposedly a spark in the fuel tank pump caused an explosion. I still think it is just as likely that flight 800 got hit by a meteor.<br /><br />By the way many modern cars have an electric fuel pump in the fuel tank, including mine. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[propforce]

An electric fuel pump fully immersed in the fuel will not cause fire in case of a spark. <br /><br />First, there won't be a "spark" in the absence of oxygen. Second, there has to be an adequate mixture of fuel & air in order for a combustion to occur. <br /><br />Don't try this at home, but suppose you can light a match in a pool of fuel, it will not burn. <div class="Discussion_UserSignature"> </div>

 

[why06]

you can carbonate anything!<br /><br />....Soda is carbonated..... all you have to do is mix it in..<br /><br />but seriously don't worry,....... If your worried the fuel tank is going to explode on a plane you've got more pressing matters to attend to....like:<br /><br />......<font color="yellow">"why would the fuel tank catch on fire?.... Oh yeah the engine blew up!"</font> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[nexium]

You can disolve perhaps a gram of carbon dioxide in a liter of water at normal pressure and temperature. Carbon dioxide may be less soluable in jet fuel and would pressurize the fuel tank if the fuel got hot. The carbon dioxide that was in solution would reduce jet engine performance at least slightly. Neil