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Newbie - Simple method to dry oil?
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Hi

Ive recently started making biodiesel but unfortunately i can only get oil that has some water in it. At present i use a small 18 litre water boiler to dry my oil before processing but this is very time consuming. I cant seem to find much info on how people dry oil. I assume a bubbler that is used to dry bio wouldnt work that well as oil is much thicker?

Would a steel drum with a heating element and a tap on the bottom work ok to dry the oil? ie pour oil through filter into the barrel, heat until it reaches a temperature near 100 degrees celcius, settle and then drain the water off out the bottom?

Some advice would be great! thanks


VW Golf MK4 1.9 tdi - B100
 
Location: Northern Ireland | Registered: January 15, 2011Reply With QuoteReport This Post
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No need to heat to 100c-heating to 60c is normally enough,then settle and drain water-alternatively use glycerol pretreating to remove water and condition your oil ready for process
 
Location: UK | Registered: October 14, 2008Reply With QuoteReport This Post
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I have an insulated 55 gallon drum with a band heater on it for my settling drum. I pour my wvo through window screening to filter it. When nearly full, around 6" from the top, I'll plug in the band heater until it reaches about 135F-140F. Unplug the heater and let it settle for a week or so. I have a drum pump mounted on the lid which I use to pump out the bottom few gallons or so of wet muck and throw that in the trash. Then I just pump from above the bottom ring when I go to make a batch. Lately I have been also mixing in my glycerol so that I can recover some of my methanol and lower my titration. After that has settled, I just pump out the spent glycerol. This also absorbs any more water if there is any left after settling.


Alvin
'01 F250 7.3 4x4 Lariat Crew
'95 Mercedes Benz E300 D
 
Location: Seattle | Registered: January 06, 2009Reply With QuoteReport This Post
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You dont say whether the water in your oil is free water or suspended, so Im going to assume its free water.

Taralec is right, 60 degrees C is hot enough to let the water settle out quickly.Any free water will form a layer under the oil and can be drained off. The suspended water, which is usually about 1000ppm, will still be in the oil and you can choose to either dry it off or contend with the extra soap that will be produced.
Glycerol pretreatment is a good option but will take a week or more to work.

A drying attachment is easy to setup if your processor has an open top. I have a u bend made of copper pipe which attaches to the circulation inlet in the processor. The open end of the u bend has a 6 inch length of threaded bar with a large washer attached to it sitting loose in the pipe. The oil is heated up to 63 degrees and pumped through the u bend. The oil forms a large bubble shape fountain. Hot air is blown over the bubble to evaporate suspended water. 2 hours of this will reduce the suspended water content to about 300ppm and processing can begin immediately. The low water content makes processing very easy with minimal soap production.
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post
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Thanks for the prompt replies!

Imakebiodiesel, you say that that the glycerol pretreatment will take a week or more to work. What do you mean by this? I thought that the oil could be mixed with the glycerol and then drained off after a day of settling? Also do i need to heat the oil before mixing with the glycerol ?


thanks


VW Golf MK4 1.9 tdi - B100
 
Location: Northern Ireland | Registered: January 15, 2011Reply With QuoteReport This Post
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Most home brewers pretreat by taking the still warm glycerol from a batch of biodiesel and mixing it immediately with 150 litres of wvo. The residual heat methanol and catalyst go to work on the wvo. Heating the wvo is not usually done as it might simply evaporate the methanol. The glycerol will settle to the bottom in a day or so but it seems to keep working for up to 2 weeks. Several things are going on all at once. The methoxide is partially processing the wvo. The glycerol is absorbing water, The wvo is absorbing excess methanol. The longer you can leave it to work the better.
When draining it can be difficult to tell when the glycerol stops and the wvo begins so it is a good idea to note how much glycerol you add and drain off slightly less than that amount before processing.
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post



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For my pretreat,Oil goes into processor through a screen to protect pump-the whole lot goes in fats crud and all-then heat and circulate to 55c,add glyc-then mix for an hour -then settle for 1 hour-drop glyc-titrate oil-mix methoxide and process-works brilliantly for me
 
Location: UK | Registered: October 14, 2008Reply With QuoteReport This Post
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That seems like a much better system. Although I have used pretreatment in the past I always found it a bit of a pain. My oil supply is currently dry and titration 2ml so I dont need to use pretreatment. If I get some low quality oil or wet oil I will try your method. How much of a reduction in titration number would you expect?
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post
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John, why not use the previous batch of glycerine as pre-treatment even if your wvo is good. Better yield regardless. Jim.
 
Location: Cape Town | Registered: May 17, 2006Reply With QuoteReport This Post
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quote:
Originally posted by JimKohler:
John, why not use the previous batch of glycerine as pre-treatment even if your wvo is good. Better yield regardless. Jim.


I agree. My oil is dry to begin with and titrates at 1.5-2, KOH. With the glycerine prewash, it drops titration to .5-.9, I recover some methanol and absorbed biodiesel., and on my single stage process I usually gain another 10-15 litres on a 170 litre batch. I can run 18% methanol and pass 3/27 in 1.25-1.5 hour.


Alvin
'01 F250 7.3 4x4 Lariat Crew
'95 Mercedes Benz E300 D
 
Location: Seattle | Registered: January 06, 2009Reply With QuoteReport This Post
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I stopped using pretreatment because I found it too much hassle but Taralec's method is much better, Im going to try it next batch.
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post
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Imake-I think you will find it is worth the effort-also I back off my meth to 17%- 18% (because I have gained some meth back during pretreat).I do an 80:20 process-keep the glyc from the 80 for pretreating next time.Once I have added the 20 and have passed 27/3-then I add ~10% water(10% of the "20" meth addition)pump round for 10 mins or so,then settle,gets rid of a whole load of soap.
This way I can do glyc pretreat and water prewash in same batch.Works really well for me
 
Location: UK | Registered: October 14, 2008Reply With QuoteReport This Post



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Thanks, thats exactly what I was going to ask you. Im very committed to continuing to use the 2 stage method with reduced water wash to finish because it is producing such high quality results. your method combines 2 stage with pretreatment without a lot of extra work and less chemicals which also appeals to my parsimonious soul.
I noticed that on a separate post you asked were there any diesel outboard motors available. Yanmar made a 36 hp model but stopped production a few years ago. They are quite rare but might turn up on ebay occasionally.
 
Location: Lismore Ireland | Registered: November 25, 2007Reply With QuoteReport This Post
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