Hi as a beginner with biodiesel, should I dry was or wet wash? I have read on both and they both seem to have there own merits. I like to keep things simple. The idea of possible spontaneous combustion scares me a little with the wood chips but putting water in my fuel? At present our batches are only small 88ltrs till we get the hang of it and scale up.
I have access to both wood chips and water maybe it comes down to a personal choice?
your inputs though would be great.
I vote for dry.
What merit does water washing have over dry washing?
I am not aware of any advantage to water washing over dry but I see many advantages to dry over water.
I always water washed because it cost me essentially nothing and there was no question it was working.
It must cost something to dry it after washing, no?
I "bubble wash"
after making a batch of biodiesel I pump it into an open-top Bubbling/ Settling tank and bubble air through it for a day or so.
I then leave the biodiesel sit for a day or two in the open-toptank and then pump it into 205 litre drums and seal it up tight.
When I want to use the biodiesel I first pump it into 20 litre open top pails with loose fitting tops where it will sit for a week or three before it is used.
My inline filter lasts much longer now than when I water washed and it is a lot easier to wash.
I do have a good reserve of biodiesel on hand so I can leave the biodiesel to sit for a minimum of 6 months before using.
An issue with making biodiesel is dealing with polluting the environment. In this country (USA) there are people that believe it is important to not pollute. Water washing crude biodiesel produces waste water that would be expensive to responsibly dispose of. Dry washing produces a smaller volume of waste. The wood chips, in that type of dry washing might be burned in the winter. Just dumping waste water, isn't a very good alternative.
Really, from testing I have done with the KF the water content of dry washed biodiesel is around the 600ppm level.
It doesnt have to be expensive to dry water washed biodiesel.http://biodiesel.infopop.cc/eve/forums/a/tpc/f/5367078823/m/5697001243/p/9
Water washing crude biodiesel produces waste water that MIGHT be expensive to responsibly dispose of, however it certainly is not expensive to responsibly dispose of in all cases.
That is true John. I water wash 200 litres of de-methed bio with 32 litres of water (4x 8 litre washes) I use little water because after my process using a small amount of catalyst the soap after de-mething is only @ 300ppm. on the few occasions the soap is higher I wash 1st with pure glycerine. This will bring the soap level down to <100ppm.
My banana plants seem to like the wash water.
Dgs; I just did some small calculations. If you used 5 grams NaOH per litre for making biodiesel for your approximately 200 litres, then that's 1000 grams NaOH catalyst used for a batch. If all the sodium present goes to making sodium soap, then just prior to water washing, 7,500 grams of sodium soap was produced. But a portion of the soap produced goes out with removal of the glycerine layer. If all the sodium doesn't go into making soap then some of the 1 kilogram of NaOH catalyst is in the wash water as sodium hydroxide, which has a high pH. I assume a high pH wash water is bad to dump into a convenient drain. But if all the sodium goes to making soap, I could recognize that is much less objectionable. There are "greenies" in the USA that never took significant science courses (like President Obama) who believe they have valid objections to what experienced chemical industry practises are. The greenies are probably, usually wrong on science issues.
Very interesting Wesley, thanks.
I have done both (see website for details on both methods), and both have their strong points and weak points.
If speed is a considerable factor, then HOT water washing is much quicker than dry media filtration. If water availability is a factor then dry filter. You can also not use either water or media filtration IF time is no biggie GL eco-system and your caustic is NaOH.
I recommend taking your time to study the subject (something most here did not have being the pioneers of these methods) and then evaluate your real world need. Done right all these methods work well, or even combinations IE: water wash with HOT water which will give results fairly quickly and then dry by heating the biodiesel while evaporating the water and finish up by running it through resin or wood chips.
The idea of using a dry method is essentially the same as using Graham's eco-system method but speeding it up which grabs the residual particulates in the resin or chips rather than waiting for gravity to do it.
** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.
Can this following method subsidize the bubble washing?:
I have a very similar nozzle.
My "bubble washing" does not include any added water.
Alkl I am doing when I bubble is de-mething
Yes I understand that, I mean can I use the method I mentioned instead of your bubble washing to try and "de-meth" the biodiesel without water washing?. I don't need to recover any methanol
You didn't mention any methods, the link just leads to a bunch of spray nozzles for sale?
What method are you talking about?
Sorry about that. The method I am referring to is the one that you squirt the oil back into itself in an open top drum and you do it using a nozzle that creates a fan shaped thin stream.
Is this method safe enough for evaporating the methanol?
Yes, if used in a well ventilated area.
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