Freezing Fuel?

Wm226 · March 11th, 2004, 10:25

Does fuel freeze? If so, what temperature does it freeze at?

Thank You,
William

PhotoPilot · March 11th, 2004, 10:49

AVGAS won't freeze, but as it gets colder water that has been absorbed will seperate and either freeze or collect in the lowest point of the system. Jet fuel is very similar to diesel and can gel at low temps if the proper additives haven't been added.

pilot602 · March 11th, 2004, 11:05

AVGAS will freeze. It's just very unlikely that it will freeze in the kinds of temperatures it would normaly be exposed to. Any liquid will freeze at some point.

Wm226 · March 11th, 2004, 11:19

Thanks Guys!

[ QUOTE ]
Jet fuel is very similar to diesel and can gel at low temps if the proper additives haven't been added.

[/ QUOTE ]

Out of curiosity, what type of additives are added to help prevent fuel from freezing?

avi8tor · March 11th, 2004, 12:01

There are different gardes of Jet Fuel. The difference between the grades is the Max. Freezing Temp., and the flashpoint. Some additives that can be added to jet fuel include anti knock additives, anti oxidants,and corrosion inhibators. For everything you ever wanted to know about Jet Fuel.

Click Here

Wm226 · March 11th, 2004, 12:05

Great link!

Thank you!

PhotoPilot · March 11th, 2004, 13:30

[ QUOTE ]
AVGAS will freeze. It's just very unlikely that it will freeze in the kinds of temperatures it would normaly be exposed to. Any liquid will freeze at some point.

[/ QUOTE ]

Agreed, but I seriously doubt that the temps found naturally on our planet would do the trick. Probably should have actually looked up the freezing point before posting, though . . .

sorrygottarunway · March 12th, 2004, 15:02

I wished they had mentioned something about prist in that link....

I'm getting the feeling that when people ask for prist, it is similar to when I ask for mayo on my sandwich at the deli.

EatSleepFly · March 12th, 2004, 16:37

[ QUOTE ]
I wished they had mentioned something about prist in that link....

I'm getting the feeling that when people ask for prist, it is similar to when I ask for mayo on my sandwich at the deli.

[/ QUOTE ]

Prist is an anti-icing additive that lowers the freezing point of water.

Jet fuel contains small amounts of dissolved water. At altitude, the cold temperatures make it impossible for the water to remain in a dissolved state, so water can actually appear in the fuel as supercooled droplets. This is detrimental because it can freeze in lines and at filters.

Prist isn't very soluble in fuel, but it is in water. Therefore, when water particles form, the Prist is dissolved in it, lowering the freezing point to prevent it from freezing in lines/filters.

Windchill · March 12th, 2004, 22:05

FSII

sixpack · March 16th, 2004, 06:36

The oil cooler on some Turbine engines is used to heat the fuel to prevent fuel freezing. Don't know the specifics because I don't fly jets (YET).

mtsu_av8er · March 16th, 2004, 08:04

[ QUOTE ]
The oil cooler on some Turbine engines is used to heat the fuel to prevent fuel freezing. Don't know the specifics because I don't fly jets (YET).

[/ QUOTE ]

Actually, the oil cooler's purpose is to cool the oil (think radiator and coolant). It has a secondary purpose to heat the fuel somewhat, but it's not going to heat the entire fuel cell. It's only going to heat fuel that's in transit to the engine in question. So, it won't prevent the fuel in the tank from freezing - at all.

Does that make any sense?

EatSleepFly · March 16th, 2004, 16:48

Depends on the engine. The Garrett engines on a B100 have both an oil-to-fuel heat exchanger (to keep fuel from freezing on its way into the engine) and an oil radiator to keep the oil temps within normal limits.

mtsu_av8er · March 16th, 2004, 22:22

[ QUOTE ]
Depends on the engine. The Garrett engines on a B100 have both an oil-to-fuel heat exchanger (to keep fuel from freezing on its way into the engine) and an oil radiator to keep the oil temps within normal limits.

[/ QUOTE ]

Wow...now that's neat!! Got any graphics to scan in? That sounds pretty neat, and I'd like to see some diagrams, charts....or just draw it, man!!!!

Minuteman · March 18th, 2004, 00:29

Most kinds of jet fuel will freeze between -40°C to -50°C

Before they killed the publication, Boeing's Aero Magazine had a neat article about polar routes and the problem of fuel getting very close to freezing. http://www.boeing.com/commercial/aeromagazine/aero_16/polar_story.html

CAVOK · March 23rd, 2004, 19:33

Since fuels are a mixture of hydrocarbons....the water in them (if any) is what will freeze at a relatively high temperature. The mix of hydrocarbons themselves all freeze at different temps...usually between -40 and -70 degrees C, and when a hydrocarbon freezes it becomes waxy (spelling?) like candle wax. So what happens is the fuel starts to freeze and gets chunks of "wax" floating around...as it gets colder it all turns into this "wax". Needless to say...the fuel pumps have trouble pumping wax, so that is where the problem starts. Our airline uses -40 C, as the "standard freezing temp" for the various grades of jet fuel we can use.

....Just got back from "Polar Operations Training" yesterday. I was anxious to type some of my new found knowledge

.

dakovich · April 2nd, 2004, 11:25

ask anyone who drives a diesel car in the winter. the diesel gels up and if you don't use a fuel conditioner you'll be chillin on the side of the road waiting for the tow-truck

EatSleepFly · April 7th, 2004, 15:50

[ QUOTE ]
Wow...now that's neat!! Got any graphics to scan in? That sounds pretty neat, and I'd like to see some diagrams, charts....or just draw it, man!!!!

[/ QUOTE ]

Mtsu, if you feel I'm incorrect, come out and say it and please feel free to back it up.

I made my previous statement based on what I learned in B100 ground school. This afternoon after coming across your unanswered question, I went back and found this reference in our Ground Training manual on the oil-to-fuel heat exchanger:

[ QUOTE ]
An oil-to-fuel heat exchanger, located in the oil tank, regulates the fuel temperature automatically when the engine is running to prevent freezing of water that is suspended in the fuel. During engine start, the "Fuel Anti-Ice Lockout Valve" is energized closed. By so doing, fuel flow through the heat exchanger is temporarily stopped, thus providing increased fuel pressure to the engine while the engine speed is low.

[/ QUOTE ]

And this quote from the AFM/POH in reference to the engine lubrication system:

[ QUOTE ]
A dry-sump high-pressure lubricating system is provided to lubricate and cool the compressor and turbine bearings and the reduction gearing. The system also supplies actuating pressure to the propeller control system and to the torque sensing components. Included in the system are a high pressure pump, three scavenge pumps, an oil filter with a bypass valve, a pressure regulator, and an oil tank. A magnetic chip detector forms part of the drain plug in the lower sump of the output housing. An external oil radiator with non-congealing capabilities keeps the engine oil temperature within operating limits.

[/ QUOTE ]

Unfortnately, neither of the engine schematics I have show this in detail, and I don't draw. Sorry to bring up an old post, just wanted to answer your question a little more thoroughly. If that doesn't answer it, I'll go bug the mechanics sometime for you.

mtsu_av8er · April 7th, 2004, 15:52

[ QUOTE ]
[ QUOTE ]
Wow...now that's neat!! Got any graphics to scan in? That sounds pretty neat, and I'd like to see some diagrams, charts....or just draw it, man!!!!

[/ QUOTE ]

Mtsu, if you feel I'm incorrect, come out and say it and please feel free to back it up.

[/ QUOTE ]

Whoa....

I was being sincere!!! I really do think it's neat, and would like to see some diagrams...lol. I'm an engines and systems geek....I kinda dig that stuff!!!! No sarcasm in that one!!!

EatSleepFly · April 7th, 2004, 15:56

OK, just thought it sounded a little condescending, thats all...

Anyhoo, I'll ask a mechanic tomorrow just to make sure its not a mistake in the training manual.

mtsu_av8er · April 7th, 2004, 15:58

No, not at all man!! I was being serious!!! I may come off like a tough guy, but I'm not all that bad....

I just think that would be a cool system to understand, though. So no big deal, however, if you come across any technical diagrams or anything geeky like that, hook it up!!!

EatSleepFly · April 7th, 2004, 16:01

You got it. I'll see what I can find. I wish I had seen this post yesterday. I spent a good chunk of time today poking around in maintenance because the plane was in for some routine stuff and its fun to see it all uncowled.

mtsu_av8er · April 7th, 2004, 19:09

Hey, here's a powerpoint outline of the fuel system on the General Electric T-64 engine. It's pretty representative of the fuel system on many turboshaft engines of it's era. Note the slide discussing the fuel flow sequence of the -419 model.

ESF, not saying you're wrong, but after digging througn some of my techno-babble tonight, I just can't find any information on any aircraft having a fuel tank warming system, and that's really why I was so excited to hear that an aircraft had such a thing. If there is, I genuinely would like to learn about it!!!

If you check out this link , go down to the part that discusses Fuel Heaters. Here, you'll see them discussed as a system that warms fuel as it flows toward the combustion chamber of the engine, removing any ice so that the filters don't get clogged.

Whewww.....my brain is burning...been a long time since I taught this information!!!!

EatSleepFly · April 7th, 2004, 19:13

No no no man...I think you misunderstood what I was saying. Its not a fuel tank warming system. Its just that the oil-to-fuel heat exchanger and the oil cooler, are seperate things. You had said in a post above that heating fuel inbound to the engine was a secondary purpose of the oil cooler. I was saying that they're two seperate items (oil-to-fuel heat exhanger, and oil cooler) on the Garrett engine (or at least thats what ground school and the manuals has me believing...now I'm beginning to wonder).

Now I'm all confused, lol...sorry!

mtsu_av8er · April 7th, 2004, 19:20

Ooohhhh......

My bad, man...give me a minute to catch up with myself....lol.

March 11th, 2004, 10:25	#1
Wm226 Senior Member Join Date: Jul 2002 Location: U.S Posts: 407	Freezing Fuel? Does fuel freeze? If so, what temperature does it freeze at? Thank You, William

March 11th, 2004, 10:49	#2
PhotoPilot Senior Member Join Date: Jun 2003 Location: Indianapolis, IN Posts: 902	Re: Freezing Fuel? AVGAS won't freeze, but as it gets colder water that has been absorbed will seperate and either freeze or collect in the lowest point of the system. Jet fuel is very similar to diesel and can gel at low temps if the proper additives haven't been added.

March 11th, 2004, 11:05	#3
pilot602 Old Skool Join Date: Oct 2001 Location: who haa Posts: 3,750	Re: Freezing Fuel? AVGAS will freeze. It's just very unlikely that it will freeze in the kinds of temperatures it would normaly be exposed to. Any liquid will freeze at some point.

March 11th, 2004, 11:19	#4
Wm226 Senior Member Join Date: Jul 2002 Location: U.S Posts: 407	Re: Freezing Fuel? Thanks Guys! [ QUOTE ] Jet fuel is very similar to diesel and can gel at low temps if the proper additives haven't been added. [/ QUOTE ] Out of curiosity, what type of additives are added to help prevent fuel from freezing?

March 11th, 2004, 12:01	#5
avi8tor Senior Member Join Date: Nov 2001 Location: Chicago, ILL. Posts: 432	Re: Freezing Fuel? There are different gardes of Jet Fuel. The difference between the grades is the Max. Freezing Temp., and the flashpoint. Some additives that can be added to jet fuel include anti knock additives, anti oxidants,and corrosion inhibators. For everything you ever wanted to know about Jet Fuel. Click Here

March 11th, 2004, 12:05	#6
Wm226 Senior Member Join Date: Jul 2002 Location: U.S Posts: 407	Re: Freezing Fuel? Great link! Thank you!

March 11th, 2004, 13:30	#7
PhotoPilot Senior Member Join Date: Jun 2003 Location: Indianapolis, IN Posts: 902	Re: Freezing Fuel? [ QUOTE ] AVGAS will freeze. It's just very unlikely that it will freeze in the kinds of temperatures it would normaly be exposed to. Any liquid will freeze at some point. [/ QUOTE ] Agreed, but I seriously doubt that the temps found naturally on our planet would do the trick. Probably should have actually looked up the freezing point before posting, though . . .

March 12th, 2004, 15:02	#8
sorrygottarunway Senior Member Join Date: Oct 2003 Location: DXR, Connecticut Posts: 1,177	Re: Freezing Fuel? I wished they had mentioned something about prist in that link.... I'm getting the feeling that when people ask for prist, it is similar to when I ask for mayo on my sandwich at the deli.

March 12th, 2004, 16:37	#9
EatSleepFly Old Skool Join Date: Dec 2002 Location: ?? Posts: 4,600	Re: Freezing Fuel? [ QUOTE ] I wished they had mentioned something about prist in that link.... I'm getting the feeling that when people ask for prist, it is similar to when I ask for mayo on my sandwich at the deli. [/ QUOTE ] Prist is an anti-icing additive that lowers the freezing point of water. Jet fuel contains small amounts of dissolved water. At altitude, the cold temperatures make it impossible for the water to remain in a dissolved state, so water can actually appear in the fuel as supercooled droplets. This is detrimental because it can freeze in lines and at filters. Prist isn't very soluble in fuel, but it is in water. Therefore, when water particles form, the Prist is dissolved in it, lowering the freezing point to prevent it from freezing in lines/filters.

March 12th, 2004, 22:05	#10
Windchill Old Skool Join Date: Nov 2002 Location: Mid-Atlantic, KMRB Posts: 1,925	Re: Freezing Fuel? FSII

March 16th, 2004, 06:36	#11
sixpack Junior Member Join Date: Jul 2003 Location: Portland, Oregon Posts: 277	Re: Freezing Fuel? The oil cooler on some Turbine engines is used to heat the fuel to prevent fuel freezing. Don't know the specifics because I don't fly jets (YET).

March 16th, 2004, 08:04	#12
mtsu_av8er Old Skool Join Date: Dec 2002 Location: Utopia Posts: 12,567	Re: Freezing Fuel? [ QUOTE ] The oil cooler on some Turbine engines is used to heat the fuel to prevent fuel freezing. Don't know the specifics because I don't fly jets (YET). [/ QUOTE ] Actually, the oil cooler's purpose is to cool the oil (think radiator and coolant). It has a secondary purpose to heat the fuel somewhat, but it's not going to heat the entire fuel cell. It's only going to heat fuel that's in transit to the engine in question. So, it won't prevent the fuel in the tank from freezing - at all. Does that make any sense?

March 16th, 2004, 16:48	#13
EatSleepFly Old Skool Join Date: Dec 2002 Location: ?? Posts: 4,600	Re: Freezing Fuel? Depends on the engine. The Garrett engines on a B100 have both an oil-to-fuel heat exchanger (to keep fuel from freezing on its way into the engine) and an oil radiator to keep the oil temps within normal limits.

March 16th, 2004, 22:22	#14
mtsu_av8er Old Skool Join Date: Dec 2002 Location: Utopia Posts: 12,567	Re: Freezing Fuel? [ QUOTE ] Depends on the engine. The Garrett engines on a B100 have both an oil-to-fuel heat exchanger (to keep fuel from freezing on its way into the engine) and an oil radiator to keep the oil temps within normal limits. [/ QUOTE ] Wow...now that's neat!! Got any graphics to scan in? That sounds pretty neat, and I'd like to see some diagrams, charts....or just draw it, man!!!!

March 18th, 2004, 00:29	#15
Minuteman Old Skool Join Date: May 2003 Location: Austin, TX Posts: 1,528 Blog Entries: 1	Re: Freezing Fuel? Most kinds of jet fuel will freeze between -40°C to -50°C Before they killed the publication, Boeing's Aero Magazine had a neat article about polar routes and the problem of fuel getting very close to freezing. http://www.boeing.com/commercial/aeromagazine/aero_16/polar_story.html

March 23rd, 2004, 19:33	#16
CAVOK Junior Member Join Date: Jan 2004 Location: Los Angeles Posts: 123	Re: Freezing Fuel? Since fuels are a mixture of hydrocarbons....the water in them (if any) is what will freeze at a relatively high temperature. The mix of hydrocarbons themselves all freeze at different temps...usually between -40 and -70 degrees C, and when a hydrocarbon freezes it becomes waxy (spelling?) like candle wax. So what happens is the fuel starts to freeze and gets chunks of "wax" floating around...as it gets colder it all turns into this "wax". Needless to say...the fuel pumps have trouble pumping wax, so that is where the problem starts. Our airline uses -40 C, as the "standard freezing temp" for the various grades of jet fuel we can use. ....Just got back from "Polar Operations Training" yesterday. I was anxious to type some of my new found knowledge .

April 2nd, 2004, 11:25	#17
dakovich Senior Member Join Date: Jul 2001 Location: Buffalo, NY Posts: 1,032	Re: Freezing Fuel? ask anyone who drives a diesel car in the winter. the diesel gels up and if you don't use a fuel conditioner you'll be chillin on the side of the road waiting for the tow-truck

April 7th, 2004, 15:50	#18
EatSleepFly Old Skool Join Date: Dec 2002 Location: ?? Posts: 4,600	Re: Freezing Fuel? [ QUOTE ] Wow...now that's neat!! Got any graphics to scan in? That sounds pretty neat, and I'd like to see some diagrams, charts....or just draw it, man!!!! [/ QUOTE ] Mtsu, if you feel I'm incorrect, come out and say it and please feel free to back it up. I made my previous statement based on what I learned in B100 ground school. This afternoon after coming across your unanswered question, I went back and found this reference in our Ground Training manual on the oil-to-fuel heat exchanger: [ QUOTE ] An oil-to-fuel heat exchanger, located in the oil tank, regulates the fuel temperature automatically when the engine is running to prevent freezing of water that is suspended in the fuel. During engine start, the "Fuel Anti-Ice Lockout Valve" is energized closed. By so doing, fuel flow through the heat exchanger is temporarily stopped, thus providing increased fuel pressure to the engine while the engine speed is low. [/ QUOTE ] And this quote from the AFM/POH in reference to the engine lubrication system: [ QUOTE ] A dry-sump high-pressure lubricating system is provided to lubricate and cool the compressor and turbine bearings and the reduction gearing. The system also supplies actuating pressure to the propeller control system and to the torque sensing components. Included in the system are a high pressure pump, three scavenge pumps, an oil filter with a bypass valve, a pressure regulator, and an oil tank. A magnetic chip detector forms part of the drain plug in the lower sump of the output housing. An external oil radiator with non-congealing capabilities keeps the engine oil temperature within operating limits. [/ QUOTE ] Unfortnately, neither of the engine schematics I have show this in detail, and I don't draw. Sorry to bring up an old post, just wanted to answer your question a little more thoroughly. If that doesn't answer it, I'll go bug the mechanics sometime for you.

April 7th, 2004, 15:52	#19
mtsu_av8er Old Skool Join Date: Dec 2002 Location: Utopia Posts: 12,567	Re: Freezing Fuel? [ QUOTE ] [ QUOTE ] Wow...now that's neat!! Got any graphics to scan in? That sounds pretty neat, and I'd like to see some diagrams, charts....or just draw it, man!!!! [/ QUOTE ] Mtsu, if you feel I'm incorrect, come out and say it and please feel free to back it up. [/ QUOTE ] Whoa.... I was being sincere!!! I really do think it's neat, and would like to see some diagrams...lol. I'm an engines and systems geek....I kinda dig that stuff!!!! No sarcasm in that one!!!

April 7th, 2004, 15:56	#20
EatSleepFly Old Skool Join Date: Dec 2002 Location: ?? Posts: 4,600	Re: Freezing Fuel? OK, just thought it sounded a little condescending, thats all... Anyhoo, I'll ask a mechanic tomorrow just to make sure its not a mistake in the training manual.

April 7th, 2004, 15:58	#21
mtsu_av8er Old Skool Join Date: Dec 2002 Location: Utopia Posts: 12,567	Re: Freezing Fuel? No, not at all man!! I was being serious!!! I may come off like a tough guy, but I'm not all that bad.... I just think that would be a cool system to understand, though. So no big deal, however, if you come across any technical diagrams or anything geeky like that, hook it up!!!

April 7th, 2004, 16:01	#22
EatSleepFly Old Skool Join Date: Dec 2002 Location: ?? Posts: 4,600	Re: Freezing Fuel? You got it. I'll see what I can find. I wish I had seen this post yesterday. I spent a good chunk of time today poking around in maintenance because the plane was in for some routine stuff and its fun to see it all uncowled.

April 7th, 2004, 19:09	#23
mtsu_av8er Old Skool Join Date: Dec 2002 Location: Utopia Posts: 12,567	Re: Freezing Fuel? Hey, here's a powerpoint outline of the fuel system on the General Electric T-64 engine. It's pretty representative of the fuel system on many turboshaft engines of it's era. Note the slide discussing the fuel flow sequence of the -419 model. ESF, not saying you're wrong, but after digging througn some of my techno-babble tonight, I just can't find any information on any aircraft having a fuel tank warming system, and that's really why I was so excited to hear that an aircraft had such a thing. If there is, I genuinely would like to learn about it!!! If you check out this link , go down to the part that discusses Fuel Heaters. Here, you'll see them discussed as a system that warms fuel as it flows toward the combustion chamber of the engine, removing any ice so that the filters don't get clogged. Whewww.....my brain is burning...been a long time since I taught this information!!!!

April 7th, 2004, 19:13	#24
EatSleepFly Old Skool Join Date: Dec 2002 Location: ?? Posts: 4,600	Re: Freezing Fuel? No no no man...I think you misunderstood what I was saying. Its not a fuel tank warming system. Its just that the oil-to-fuel heat exchanger and the oil cooler, are seperate things. You had said in a post above that heating fuel inbound to the engine was a secondary purpose of the oil cooler. I was saying that they're two seperate items (oil-to-fuel heat exhanger, and oil cooler) on the Garrett engine (or at least thats what ground school and the manuals has me believing...now I'm beginning to wonder). Now I'm all confused, lol...sorry!

April 7th, 2004, 19:20	#25
mtsu_av8er Old Skool Join Date: Dec 2002 Location: Utopia Posts: 12,567	Re: Freezing Fuel? Ooohhhh...... My bad, man...give me a minute to catch up with myself....lol.

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