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Hot vs. Cold Blending
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While blending my 20 gallon batch today, I got to thinking about a few things.

First, I've seen users heat their mix while blending, the settle, while others just cold mix and then settle. What is the difference?

I'm curious about such techniques, as which would be better for mixing, and for settling out any participates.

Over the last few days, I've been giving considerable thought to hot and cold blending, and methods to go about the process of settling. As of right now I cold blend about once every other week, and let it settle about 24-48 hours before using. Settling is done outside where outside temps have been varying from 50 degrees F at night to 75 degrees F during the day. It's apparent to me from my experimenting that consistent temps are better for settling.

With this in mind, do you suppose one would get better blending results while mixing while hot and then let settle? Or Would it better then cold blend, heat the blend, and then let settle?

To shed some light to aide myself in finding the answer, I stuck a jar of canola WVO in the fridge for three days after hot centrifuging. After the first of three days I noticed white patches forming in the canola WVO, and continued to get bigger the two days after. I took the jar out of the fridge and let settle for three days at ambient room temp of 72 degrees F. The white patches settled to the bottom of the jar and the canola WVO was considerably more clear than when first put in the fridge.

So, looks like more experimenting to come!

Thoughts? Comments? Experience words of wisdom?
 
Location: Columbus, GA, USA | Registered: September 29, 2011Reply With QuoteReport This Post
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I do all my processing cold. My cold upflow system is specifically designed to remove the troublesome PHO and fats from the UVO. It also separates out nearly all the water. I cold blend the other components of my fuel with the cleaned UVO, then mix thoroughly, while passing it through a column of Quik 'n Dri to remove any remaining water. The mix is then tested with a carbide manometer to ensure it's dry. The mix is allowed to settle outside in the ambient temperature where any components which might drop out with the cold settle to the bottom of the barrel. As needed, the fuel mix is pumped through a 5µ filter into the vehicle tank. Since adopting this method I've never had any filter or screen clogging problems and I get trouble-free operation all year long even in temperatures as low as minus thirty.



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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quote:
Originally posted by john galt:
It also separates out nearly all the water. I cold blend the other components of my fuel with the cleaned UVO, then mix thoroughly, while passing it through a column of Quik 'n Dri to remove any remaining water.


A while back you were adament your upflow system removed ALL the water and berated anyone that suggested different.
Now it only removes " Nearly " all the water and you have to put it through something else to make sure it IS actually Dry.

What happened? Don't tell me you discovered your system wasn't as perfect as you made it out to be over and ovver and over and..... i'm sure there is some good excuse for the difference in position.

Roll Eyes
 
Registered: July 30, 2010Reply With QuoteReport This Post
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It amazes me just how much variation there is in the way people work with WVO.This is entirely logical if you note how much climate, cars/trucks, and restaurants vary. This is also because we measure one outcome- driving satisfaction, and that varies wildly too. I no longer mix my blends at all, because I allow my cubies filled with filtered oil to sit before I pour them into the tank, and leave the last few inches to be refiltered with the raw WVO. I pour my RUG in by itself at the beginning or end of the filling process.
I have taken the waste removed from cold-upflow oil and found that as much as a quarter of it is liquid. I have a hard time finding WVO so I cannot afford to waste this bit. My preference is to do a half-assed job of filtering through vacuum cleaner bags from the Goodwill, and rely on a spin-on oil filter as prefilter in the car. Cleaning WVO is a series of stages. Gross filtering on land protects the vehicle's prefilter from too rapid plugging, the prefilter extends the life of the expensive final filter. All we care about is getting a usable life from that final filter.Each of my filtering and blending steps is directed to that final filter...including adding RUG as a cold-starting aid...it provides a fluid to feed the engine during the cold minutes before the WVO is warmed by my fphe enough to melt fat crystals in the filter pleats. If we could, we would skip all the rest of this and pour oil from the fryer directly into the tank... but we compromise to make the driving experience more practical. There are a thousand ways to accomplish this, if we just focus on keeping that final filter clean. Respectfully yours,
 
Location: puget sound | Registered: December 14, 2009Reply With QuoteReport This Post
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When I started using cold upflow settling many years ago, the HotPanTest was the generally accepted best method of detecting water in VO. Samples from the upflow system tested dry by the HPT. However, dissolved and suspended water contamination in the range of 500ppm and less is undetectable with the HotPanTest. As well, the HPT isn't a viable test for fuel blends. The recently developed Carbide manometer is a better test for water which quantitatively measures water undetectable with the HPT, and is particularly useful for fuel blends. Dry fuel is essential for successful long term operation.
http://make-biodiesel.org/Qual...for-water-in-vo.html



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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what are the psychics of hot and cold blending?

I'm sure it does make a difference as it's been put out to heat your mix when making biodiesel...
 
Location: Columbus, GA, USA | Registered: September 29, 2011Reply With QuoteReport This Post



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What do you really want to know. The question makes no sense.



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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I haven't the correct wording, but here's a try:

I understand, to a point, that chemicals, in this case; diesel and canola WVO have different properties at different temperatures. The only difference that I know of is the viscosity. Are there any other differences?

This type of thought in mind, why is it better to blend mixes such as biodiesel hot versus cold? Most folks cold blend their WVO/RUG/Diesel/ect. Does blending a mix hot or cold change the properties affecting gel point? Final mix viscosity at certain temperatures?
 
Location: Columbus, GA, USA | Registered: September 29, 2011Reply With QuoteReport This Post
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Various pure vegetable oils have different properties which can affect their combustion properties when used as fuel in diesel engines.
http://journeytoforever.org/biodiesel_yield2.html
http://www.omafra.gov.on.ca/en...t/2006/19cpo06a5.htm
http://journeytoforever.org/bi...vegoilslitreview.pdf

These properties of vegetable oils can be quite different from those of petroleum fuels
http://www.engineeringtoolbox....peratures-d_171.html

Used vegetable oil can also be quite different from pure vegetable oil depending on what's been cooked in it, how long it's been used, and at what temperature. UVO typically contains food particles as well as water, fats and hydrogenated oil from the items cooked in it. These all can alter the combustion and storage characteristics of the UVO.

Hot processing and hot blending will keep components with high melt point temperatures in the fuel solution. If the vehicle fuel system isn't entirely heated, then these components will settle out and cause problems blocking screens and filters.

quote:
Does blending a mix hot or cold change the properties affecting gel point? Final mix viscosity at certain temperatures?


Not in my experience if I understand the question correctly.



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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I blend at ambient temperature, usually 60 degrees and above. My settling barrels are at 60 plus degrees as well. Has worked well for 8 years.


And on the eigth day the LORD created the turbocharger
 
Location: Watertown, NY/Ocala, FL | Registered: August 14, 2002Reply With QuoteReport This Post
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quote:
I blend at ambient temperature

Yeah, so do I. This week it's been 25 to 30. Sometimes it's colder sometimes it's warmer. It's been working fine for about 7 years so far.



 
Location: coldest N.America | Registered: May 03, 2005Reply With QuoteReport This Post
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I am new. working on a processing unit. its not done and never will be buts its producing.

I have done experiments in blending in mason jars. my findings are as follows:
1. my control samples were a 0.5micron filtered WVO/WMO mixed jar and an unfiltered settled WVO/WMO mix jar.

2. after 2 weeks and dropping temperatures both jars settled even more. the filtered jar is currently at half full of sediment. the unfiltered jar has three layers (clear, cloudy, dark cloudy top to bottom) equal size bands.

hypothesis: the filtered oil is less dense and therefor needs more time to settle as saturated fats appear to be more numerous in the filtered jar even though both were from the same batch.

3. other jars were drown from the same batch and mixed with diesel and or low octane RUG. all three jars precipitated a very small quantity of particulates which immediately settled to the bottom. and the fluids appear cloudy.

hypothesis: the fuel stabilizers in diesel and RUG prevent most of the saturated fats from coming out of solution (ie:gelling) and causes a drastic density drop allowing heavier particulates suspended in solution to precipitate. or and I wouldn't know why but there is an actual chemical reaction occurring.

4. I drew 2 jars to mix 50/50 with diesel to analyze the necessity of providing adjitation for mixing. my findings were that the jar that was mixed only by gravity pouring (as you would into your vehicle) settled with diesel mostly on top and the jar that was mixed by manual shaking remained uniformly mixed.

conclusion: whatever is in your tank will not mix completely with what you put in it and may mix better as you drive.

I hope this helps.
 
Location: south georgia | Registered: January 13, 2015Reply With QuoteReport This Post



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sooo...0.5micron filtered oil had the most sludge placement per volume. it was cold. this was surprising but adding diesel and mixing clears it up. also, you should def settle again after you blend.

I plan to heat my oil, dump it into the holding tank, recirc it with a pump to mix it, make my blend, mist water on top, and then settle it.
 
Location: south georgia | Registered: January 13, 2015Reply With QuoteReport This Post
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