Manganeese or other metalic jet fuel additives

Manganeese or other metalic jet fuel additives

Postby TillamookTurbine on Sat Apr 18, 2009 4:47 pm

Anybody have much experience with metallic or or other inorganic fuel additives in tubines? I see manganeese compounds are used some for holding down corrosion in the hot section. Ammonia compounds can decrease NOx's, I've read. In the rocket world, attempts have been made to load kerosene (RP1) with aluminum powder to increase the heating value. Solid rocket fuel commonly carries aluminum powder. The space shuttle SRB's use it at about 10%. Above that and the aluminum oxide in the plume erodes the nozzle, too much. Isn't emery cloth aluminum oxide?

Terry
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Re: Manganeese or other metalic jet fuel additives

Postby j79guy on Sun Apr 19, 2009 9:33 pm

Not in the industrial/Marine world. Not that the Marine units don't need additives, as the crap the marine engines have to burn sometimes boggles the mind. However, it generally is standing Naval policy to "Burn what you brung", without any conditioning, or other "pandering" to gas turbine longevity.
Industrial units too, tend to run what is delivered to the tank. The fuels I've seen range from top grade diesel, to Saudi "Distillate", which is basically the stuff that runs straight out of the ground, with minimal conditioning. (Filtration only.) Saudi power plants, you can see the brown coloured exhaust plumes from miles away, and once on-site at the plants, everything is permeated with that smell of raw distillate.

Industrial turbines, generally run the other way 'round to what you think, in terms of fuel. We put specialized coatings on the turbine hot section, to accomodate the fuel being used. Locally here, there are a number of Solar turbines running "sour" gas as the fuel. Yes, they will run fine, up to about 1.5% H2S content. Sodium in the fuel obviously is a hot section parts killer, but again, with the correct application of applicable hot section coatings, even a significant sodium content can be handled.

Yes, aluminum oxide indeed is the prime abrasive of certain types of sandpaper, or media blast, parts cleaning cabinents. No wonder the rocket nozzles erode.

Interesting topic, of which I certainly am not an expert. Hopefully someone else here will chime in.

Robin.
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Re: Manganeese or other metalic jet fuel additives

Postby f4dj79 on Mon Apr 20, 2009 1:14 pm

So my opion is this the ASTM group has created a bible of sorts for fuel and the many things you can do. Then there is the expirementation method, add some of this and some of that and if does not explode, go to the next step pour it, if does not explode go to next step, try to burn it, if explodes use it!
All kidding aside I have included just some of the data I have complied for up coming fuels expirement with J34. I have tons of papers and junk on what to add. Robin said it very well, the metalic additives cause more troubles then they are worth. Now here is a good idea if you want to include additives, why not inject them just before the fuel goes in the engine. Nothing says were you have to apply injectable additives if they are liquid. That way you could add a little at a time and see what happens. In a turbine it should very predictable, in a rocket motor that may be a different story. I do know there is a lot of data on engine operations with different fuel additives some things were good and some were very bad. I was not aware that the shuttle used fuel cut with metals for the main engines. I know the solid fuel boosters use that red stuff that is very bad. below is an article on the solid fuel additives.

The main fuel, aluminum is used because it has a reasonable specific energy density of about 31.0MJ/kg, but having a high volumetric energy density, as well as being difficult to accidentally ignite.
The propellant is an 11-point star-shaped perforation in the forward motor segment and a double-truncated-cone perforation in each of the aft segments and aft closure. This configuration provides high thrust at ignition and then reduces the thrust by approximately a third 50 seconds after lift-off to avoid overstressing the vehicle during maximum dynamic pressure propellant.
The propellant mixture in each SRB motor consists of ammonium perchlorate (oxidizer, 69.6% by weight), aluminum (fuel, 16%), iron oxide (a catalyst, 0.4%), a polymer (such as PBAN or HTPB, a binder that holds the mixture together, also acting as secondary fuel, 12.04%), and an epoxy curing agent (1.96%). This propellant is commonly referred to as Ammonium Perchlorate Composite Propellant, or simply APCP. This mixture develops a specific impulse of 242 seconds at sea level or 268 seconds in a vacuum.



I have use solid fuel rocket motors for my estes rockets and know just how dangerous and safe they are. I even have played with some exoitic rocket fuel that was made up for the larger model rockets. It sure did have some metal oxidies in it and it was a pale red and it seem to me it was stable enough.
However getting back to liquid fuel if you can get a specific gravity float to test properly then the fuel is probably safe. Again I would look in the ASTM guide book for fuel additives to learn more about the recommended additive amounts

http://en.wikipedia.org/wiki/Corrosion_inhibitor
http://en.wikipedia.org/wiki/Jet_fuel
http://en.wikipedia.org/wiki/Aviation_fuel
http://yarchive.net/env/turbine_fuel.html
http://www.astm.org/Standards/D2880.htm
http://www.gepower.com/prod_serv/produc ... r3481c.pdf
http://www.chemtura.com/bu/v/index.jsp? ... 0315acRCRD
http://www.astm.org/BOOKSTORE/BOS/TOCS_2008/05.04.html
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Re: Manganeese or other metalic jet fuel additives

Postby f4dj79 on Tue Apr 21, 2009 10:49 am

Terry
Here is another atricle that might help with info. on what is currently being done to stationary turbines
WB

http://www.epa.gov/ttncatc1/dir1/gasturb.pdf
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Re: Manganeese or other metalic jet fuel additives

Postby TillamookTurbine on Tue Apr 21, 2009 1:10 pm

Thanks WB. Fuels research is the hot topic right now. I'm periphereally involved with two proposals for fuel research. If either or both are awarded, I will be involved with setting up some kind of test bench that will start a J85/ CJ610 or some other engine on Jet A and then switch after the clearances are stabilized to the research fuel.

Terry
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Re: Manganeese or other metalic jet fuel additives

Postby j79guy on Tue Apr 21, 2009 8:10 pm

Terry,

Let me know whar you are underway with this project. I built a J85 test cradle set up for measuring thrust with strain gauges. The project imploded, and I was left with the cradle, with no use/home for it.

Anybody ever mess with anhydrous ammonia as a fuel? Looks to me like it should "handle" the same as propane, with provisions made for corrosion resistance in the liquid phase. Once vapourised, should run in a gas turbine fine wouldn't you think?

Robin.
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Re: Manganeese or other metalic jet fuel additives

Postby TillamookTurbine on Wed Apr 22, 2009 8:27 am

I may take you up on the J85 hardware. I converted the thrust measurement stand that I used for the J85 during RASCAl to be the thrust stand for the 11" hybrid. Since that program's still ongoing, I'll need one for the J85 if that program goes.

You'r also correct about ammonia. That's one of the alternative fuel programs that I referred to in the earlier post. Here's a website about ammonia: http://www.ammoniafuelnetwork.org/ .

Terry
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Re: Manganeese or other metalic jet fuel additives

Postby f4dj79 on Wed Apr 22, 2009 9:53 am

Wow
Anhydrous Ammonia NH3, that is very bad stuff and volatile at that. I have messed with this stuff in refrigeration units. It seems to me that it is not quite as bad as hydrazine but real close. I messed around with Hydrazine N2H4 in the Air Force on the F-16's and this stuff is so dangerous. Either gas or liquid,it has that, (if you smell almonds you are in trouble), because it is so toxic. When compressed both become very volatile and that is why they make such go rocket fuel. PPE (personal protection gear) is aboslute need for both that is 100% contaniment.

So My question is this. Using NH3 are the expirements using vapor (gas) or liquid. I am just trying to understand just how dangerous the NH3 is, I remember that you should not get it on you or breath the vapors.
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Re: Manganeese or other metalic jet fuel additives

Postby j79guy on Wed Apr 22, 2009 7:38 pm

Anhydrous ammonia, as in farmers fertilizing the heck out of their crops with it. Here, there are big storage tanks in the middle of farming country, so the local guys don't have to drive so far to fill up.
Boiling point is -33C. and vapour pressure is close to liquid propane, so if you have stainless hardware, handling should be the same as propane. (?) I would like to run on vapourous NH3, vapourized the same as propane, and fed into the engine through traditional natural gas type injection nozzles, or through vapour propane injectors on my pickup truck. Ok how dangerous is it? The farmers aren't keeling over and they are notorious for not using protective equipment or procedures. I'm running my test cell on vapourous propane now, and it seems to be a natural to try some NH3.

Robin.
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Re: Manganeese or other metalic jet fuel additives

Postby TillamookTurbine on Thu Apr 23, 2009 3:28 pm

All correct about the dangers of NH3. However, if one were trying to push gasoline as a fuel today, I expect there'd be a lot of resistance due to its flammability and danger. One advantage of NH3 is that other than the synthesis of it from natural gas, no carbon is produced in its combustion. Also, NH3 is used in coal power plants to treat the NOx emissions.

I don't expect any major shift to NH3 soon, but I hope to participate in some research to further investigate its use in turbines.

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