Fuel Stratification in cold temperatures

[beyond biodiesel]

Fuel Stratification in cold temperatures

A way to reduce the high melting point esters (HMPEs) in a fuel blend might be to employ fuel stratification.  Fuel stratification occurs near the gel-point of a component in a fuel blend.  The reason for fuel stratification is, as a component in a fuel blend approaches its gel-point it precipitates out of solution and becomes dense, which means it is going to move to the bottom of the tank.  So, we can take advantage of Fuel Stratification in cold temperatures, if we have a cone, or domed, shaped bottom on a settling tank, and we keep that settling tank unheated and out side on the shady part of our shop, and we drain it early in the morning, then we could drain off the thick component of our blend first thing in the morning.  This might be all one has to do to remove the high gel-point components in one's fuel blend.  Then the high gel-point components in one's fuel blend can be stored for use in warmer weather.

Sources:
" Fuel stratification can occur when an aircraft is turned around after a long flight. Any residual fuel may be very cold (say –30 degrees C). This fuel can lie on top of the colder, denser fuel from one location to another in the aircraft.

Aircraft Fuel Systems

Roy Langton, Chuck Clark, Martin Hewitt - 2009 - Science - 345 pages
Fuel stratification:

http://books.google.com/books?id=9ndqO2hsUU8C&lpg=PA16&ots=8UHNiEJvBM&dq=Fuel%20Stratification&pg=PA16#v=onepage&q=Fuel%20Stratification&f=true

Temperature Stratification and Fuel Use During Winter in Three Pennsylvania Broiler Houses
1.   E. F. Wheeler,
2.   J. S. Zajaczkowski and
3.   R. W. J. Weiss
1.   The Pennsylvania State University 228 Agricultural Engineering Building Dept. of Agricultural & Biological Engineering University Park, PA 16802; Phone: (814) 865-3552; FAX: (814) 863-1031
1.   R. M. Hulet
+ Author Affiliations
1.   Dept. of Poultry Science The Pennsylvania State University University Park, PA 16802; Phone: (814) 865-3411; FAX: (814) 865-5691
1.   E. F. Wheeler, E-mail:efw2@psu.edu
Abstract
Providing a comfortable, uniform environment for broilers is one goal of ventilation, but minimizing fuel consumption is often an overriding consideration during cold weather. Three broiler houses in central Pennsylvania were monitored over three complete flock cycles for temperature conditions to document the impact winter ventilation management had on house environment and fuel use. Undesirable temperature stratification resulted in chick-level temperatures that averaged over 3.0 °C (5.4 °F) cooler than target temperatures on the day of chick arrival at the poultry house. Temperatures at the thermostat sensor height of 1.5 m (5 ft) were closer to desirable conditions. Space heaters (furnaces) directed heated air well into the room, but when the ventilation system inlets did not provide adequate mixing of this heated air with cooler outside air, temperature stratification developed. This was particularly a problem at low minimum ventilation rates when timer fans were employed. Timer fans were not necessarily effectively managed in these facilities. Monitoring environmental conditions at bird level is a first step in eliminating cool floor temperatures. A more uniform temperature can be maintained when more effective air mixing discourages temperature stratification development. Partial house brooding was an advantage because approximately one-third less fuel was utilized with an opportunity for tighter environmental control in a smaller space.
http://japr.fass.org/content/9/4/551.short

[veggie]

You bring up an interesting point.
We tend to think of adding heat to de-water and settle WVO.
I had not considered chilling.
Perhaps cold filtering also fits in somewhere ?

veggie

[beyond biodiesel]

Hi Veggie, most people think of heat when they think of fractional distillation; however, just as every fraction in a compound solution has a unique boiling point, it also has a unique freezing point, so freeze distillation is just as valid as heat distillation.

[LowGear]

That's how I get the pork fat off my gravy.

Casey

[beyond biodiesel]

Using Fractional freezing to reduce the gel-point of a waste oil blend

From Wikipedia, the free encyclopedia
Fractional freezing, or freeze distillation, is a process used in process engineering and chemistry to separate two liquids with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals, or by partial crystallization of a liquid, for example "freeze distillation", also called "normal freezing" or "progressive freezing".

Partial crystallization can also be achieved by adding a dilute solvent to the mixture, and cooling and concentrating the mixture by evaporating the solvent, a process called "solution crystallization".[1] Fractional freezing is generally used to produce ultra-pure solids, or to concentrate heat-sensitive liquids...

In Alternative Fuels fractional freezing is commonly employed through the simple method of reducing the gel-point of Biodiesel, SVO, blends and other alternative diesel fuels, whereby esters of higher Gel point are removed from esters of lower Gel point through cold filtering, or other methods to reduce the subsequent alternative fuel Gel point of the fuel blend. This process employs fuel stratification whereby components in the fuel blend develop a higher specific gravity as they approach their Gel point and thus sink to the bottom of the container, from which they can be removed.