Diesel Fuel Viscosity at Low Temperature

  • #1

Main Question or Discussion Point

I need to do some head loss calculations for pumping diesel fuel or No. 2 fuel oil from a storage tank to an emergency generator. I see in many places that diesel fuel is specified to have kinematic viscosities of 1.3 to 4.1 cSt at 40C. However, under worst case scenarios, this fuel is likely to be at or near freezing. I suspect the viscosity could increase one or more orders of magnitude at 0C. Does anyone have information on the variation of viscosity with temperature? Ideally, some sort of power law would be great. Alternatively, links to graphs will do.

Thanks,
Bent
 

Answers and Replies

  • #2
brewnog
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Is this some homework question or something?
 
  • #3
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Is a diesel engine power station located at north Alberta in Canada. The diesel fuel will be delivered once each year during winter time. pump it at temperature expected to be -45 Degree C.
 
  • #4
brewnog
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Diesel at -45C will wax. At 0C it will start to cloud, and at around -10 it will gel.
 
  • #5
Ivan Seeking
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Brewnog, are you aware of any means by which one can lower the cloud or gel temp?
 
  • #6
brewnog
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There are various cold flow improvers which can be added to the fuel to lower gel and cloud point, sometimes by 20-30 degrees. However, I don't have experience of using any.
 
  • #7
Danger
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I don't suppose that you could just heat the tank?

In my brief, hideous experience with a U-Haul dealership, we were supplied with an anti-gel agent for the truck tanks. At about -20 the damned things would drain both on-board 12V batteries and the booster cart, and even then probably not start. I don't know how much of that was a fuel problem and how much was just lousy motors.
 
  • #8
Ivan Seeking
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I don't suppose that you could just heat the tank?
What about when the car or truck is just sitting? [ah, you weren't responding to me]

One of the drawbacks for biodiesel is that the cloud point temp is higher than regular diesel [winter blend]. If you look at the following page
http://www.nearbio.com/nearbio/mapper.php

you will note that only the weaker blends of biodiesel are used in the coldest regions of the country. If this problem can be addressed, it would go a long way towards the use of B100..or at least towards having B20 as a national minimum standard.

Btw, the state of Washington has a ~B2 minimum requirement already.
 
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  • #9
Danger
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What about when the car or truck is just sitting? [ah, you weren't responding to me]
True, but I should have specified. Yeah, I was thinking of an insulated bulk tank with a low-wattage immersion heater or maybe a circulating type. I don't know if that's practical or not.
 
  • #10
FredGarvin
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I have no idea if it has ever been used in a biodiesel, but the standard for jet fuels, and would also work for most diesels, is PRIST. It's inexpensive enough to try some experimentation. If it works as well as it does on jet fuel, the freezing point is suppressed to around -45°F.

http://www.csdinc.org/prist/
 
  • #11
brewnog
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Fuel tank heaters are definitely an option, though you have to be careful with biodiesel because higher temperatures promote bacterial growth that 'eat' the fuel over time.
 
  • #12
Ivan Seeking
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Why is it that I keep thinking that I need to add EDTA to my biodiesel? :biggrin:
 
  • #13
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Put a heater ribbon around the pipe and lag. These ribbons come with a controller etc so you don't vapourise
 
  • #14
From an avid skier and layman type terms in oz, as far as i am aware they mix standard heating oil into the diesel, without it, most diesels cars wont start after a couple of hours in -temps as it turns to jelly.....its the lines that freeze being easy to cool and no amount of glow will help. you need to run out as much as possible before hitting Jindabyne and fuel up locally before going up the hill, we dont deal with the temps you guys do tho. Rather old post but i thought it might differ a touch from majority of users in US.
 
  • #15
Danger
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we dont deal with the temps you guys do tho. Rather old post but i thought it might differ a touch from majority of users in US.
You guys from tropical climates really bug me. :tongue:
Never mind the US; try out Canuckville for coldness. It routinely hit's -45° C in winter, and I've experienced -65 F (back in the early 60's, before we went metric). That's not too bad in itself, but once you get the wind-chill factor involved, it starts to get cold. Our weather reports regularly remind us to wear toques and mufflers, because exposed skin will freeze in less than 30 seconds.
My consolation is that Arildno probably has it worse in Norway. :biggrin:
 
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  • #16
Ranger Mike
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last year when gasoline hit $4 plus a gallon I traded in the convertible and got a 44 MPH VW diesel..and a kit from http://www.frybrid.com/ [Broken] ..this permits using waste vegetable oil filtered and dewatered in the fuel tank ...have not installed it yet though..and for the WVO to work . it has to be preheated to 120 degree F..so check out the various heaters at frybrid...one cheap alternative is to plumb a hose from the diesel water pump to a submerged heater in the storage tank and return the line back to the diesel...use the heat available from the diesel to good use..you can even snake the fuel line from the storage tank thru one of the water li nes( antifreeze..obviously)
i.e you have the diesel fuel line (3/8") aluminum or steel running inside a 1 inch diameter hose that carries the antifreeze.
and bury the sucker or insolate it

....it is mechanical, simple and cheap
 
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