Diesel Fuel Viscosity at Low Temperature

In summary, diesel fuel has a kinematic viscosity of 1.3 to 4.1 cSt at 40C. However, under worst case scenarios, this fuel is likely to be at or near freezing. Some means of lowering the cloud or gel temp is needed. The state of Washington has a ~B2 minimum requirement already.
  • #1
BentFranklin
1
0
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
 
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  • #2
Is this some homework question or something?
 
  • #3
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
Diesel at -45C will wax. At 0C it will start to cloud, and at around -10 it will gel.
 
  • #5
Brewnog, are you aware of any means by which one can lower the cloud or gel temp?
 
  • #6
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
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
Danger said:
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
Ivan Seeking said:
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
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
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
Why is it that I keep thinking that I need to add EDTA to my biodiesel? :biggrin:
 
  • #13
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 won't 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 don't 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
aussieclutz said:
we don't 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
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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1. What is diesel fuel viscosity at low temperature?

Diesel fuel viscosity at low temperature refers to the thickness or resistance to flow of diesel fuel when it is exposed to cold temperatures, typically below 32 degrees Fahrenheit. It is an important characteristic to consider for diesel engines operating in cold climates.

2. Why is diesel fuel viscosity important at low temperature?

Diesel fuel viscosity is important at low temperature because it can affect the performance and efficiency of diesel engines. If the fuel is too thick, it may not flow properly through the fuel system, leading to engine malfunctions and potential damage. If the fuel is too thin, it may not provide enough lubrication for engine components, causing wear and tear.

3. How does cold temperature affect diesel fuel viscosity?

Cold temperature can cause diesel fuel to thicken and become more viscous due to the paraffin wax molecules in the fuel solidifying. This can lead to difficulties with starting the engine, reduced fuel flow, and increased stress on the engine.

4. What is the ideal diesel fuel viscosity at low temperature?

The ideal diesel fuel viscosity at low temperature will vary depending on the specific engine and climate conditions. In general, it is recommended to use diesel fuel with a viscosity of 3.0 centistokes (cSt) or less at low temperatures to ensure proper engine performance and avoid potential issues.

5. How is diesel fuel viscosity at low temperature measured?

Diesel fuel viscosity at low temperature is typically measured using a viscometer, which is a device that measures the resistance of a fluid to flow. The most common unit of measurement for diesel fuel viscosity is centistokes (cSt). Fuel suppliers and manufacturers may also provide data on the pour point and cold filter plugging point of diesel fuel, which are related to its viscosity at low temperature.

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