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Acid/Base reaction 41% Glycerol produced
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Good day,

I have made my first 100 liter batch of biodiesel using the Acid/Base method:
Start litration 9.5

I did the Acid reaction:
97.5ml H2SO4 98%
12 liters of methanol

Let it settle over night then mixed it as there was nothing to drain at the bottom, did the titration again and ended up with 2.2 - not bad for a first try.
Did the Base reaction:
1.13 kg of KOH
8 liters of methanol

and let it settle for 8 hours and started draining the glycerol, I thought it would be roughly 20 liters as 20 liter of methanol was added but it came to 41 in total that was drained off. How could this happen? The Bio passed the 3/27 test with little soap particles in the test but no veg oil.

My oil was a bit wet to start with but how could 41 % be glycerol?
 
Registered: March 24, 2015Reply With QuoteReport This Post
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Are you sure about the soap content, when you go to the transesterfication step without draining the acidic junk a good portion of the caustic would be used up neutralizing the acid. When the acid is neutralized water is a byproduct!
The junk can either drain to the bottom or float on top. Reduce the amount of methanol to 10% or less (8%) to ensure the junk settles to the bottom.
To get the real picture on how well your AE worked you would have to mix everything up before draining the junk then do a titration test. your starting T was 9.5, then add the T amount for the acid used, in this case about 2 (2 points for each ml of acid/ltr of oil), subtract the ending T from 11.5 to see how well the AE worked.
You can't get those kind of results from AE unless the oil is very dry, less than 500ppm water.
your claim of passing 3/27 don't make sense to me nor does the ending T The amount of byproduct on the other hand makes sense for a Base reaction that was starved of caustic. Tom


" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
 
Location: Manitoba Canada | Registered: March 24, 2009Reply With QuoteReport This Post
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Tom, attached is the 3-27 test with small white particles but no unreacted oil, it is cloudy because I disturbed it to show you.
I will try using 8 % methanol to let the junk settle to the bottom maybe that works. during the washing of the biodiesel there is a considerable amount of emulsion that formed but I will wash it with warm water tonight maybe it breaks the emulsion layer.

Imagetest3-27.jpg (22 Kb, 9 downloads)
 
Registered: March 24, 2015Reply With QuoteReport This Post
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Using the acid/base reaction is not the easiest thing to do on your 1st batch.

I appreciate that you want as much biodiesel as possible from your oil, but a titration of 9.5 is not excessive to just do a base reaction on, as long as you glycerol pre-treat your oil 1st.

Try adding @ 500 gms of KOH in 2 to 3 litres of methanol, then add this to your 41 litres of glycerol. Mix this with your next 100 litres of oil. @ 50degs C for 1 hour, leave overnight then drain the glyc.

Use 7 gms KOH/litre of oil + 16% methanol, you will end up with 90+ litres of biodiesel.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post
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Hi Dgs,

quote:
Originally posted by Dgs:
Using the acid/base reaction is not the easiest thing to do on your 1st batch.

He said "I have made my first 100 liter batch of biodiesel using the Acid/Base method:"
I understood this to mean it is his first acid/base batch, not his first batch of biodiesel, but I could be mistaken.

How do you think the titrationless method would work out in this situation? Wink

This message has been edited. Last edited by: Tilly,






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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I think It work more efficiently than his a/e process so far.

Loosing the 5% or so FFA's by neutralisation is not really significant as long as the resultant water is removed by glyc pre-treatment before the first actual reaction.
 
Location: YORK UK | Registered: April 27, 2014Reply With QuoteReport This Post



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Hi Dgs,

quote:
Originally posted by Dgs:
I think It work more efficiently than his a/e process so far.

Loosing the 5% or so FFA's by neutralisation is not really significant as long as the resultant water is removed by glyc pre-treatment before the first actual reaction.
You have misunderstood my question.
I am not talking about your above instructions,
I am talking about the latest titrationless method
http://www.biopowered.co.uk/wi...ss_with_no_titration

"The process

No need to Titrate (but you can if you want to)

Make your first stage methoxide solution with base amounts 3.5g/l for NaOH or 5g/l KOH x full batch size + 80% of normal methanol amount.
Put this first stage methoxide mix into the processor at normal reaction temperature, and mix for an hour.
Stand for 20 minutes and drain off the glycerol into a clean container, and seal.
Do your 3/27, 5/45 or 10/90 test and measure the amount of drop out.
Determine the amount of unprocessed oil in your batch from the dropout.
Make up the second stage methoxide by mixing "unprocessed oil volume x 20%" methanol with "unprocessed oil volume x base" catalyst.
Now mix as normal for second stage
Do another 3/27 test after 30 minutes to check conversion. If this does not give a clear pass continue mixing for another 30 minutes - it should give a clear pass. If not go to step 4 above and repeat but with minimal methanol.

If you know you normally have feedstock titrating above 4 you can raise your first stage base to 6 or 7g/l NaOH. Alternatively you can opt for a multi stage process which will help reduce the amounts of soap and glycerol.

If you find you are not getting any glyc dropping from the 1st stage add some more methoxide in stages of 1g/L of oil and circulate for 30 min's or so, keep doing this until your glyc drops, note the amount needed and use this for your 1st stage amount for future batches assuming you use oil from the same suppliers as your test batch.

If your oil is very variable in quality you may need to titrate each batch to determine stage 1 methoxide, you will still get the benefit of less chemicals used but won't get the easy life a consistent supply of similar oil would give. Glycerol_wash will help a lot if this is the case.

If your process involves whole batch demeth or water prewash, the stage one glycerol should be returned to the mix first. Although you may be concerned that the first stage NaOH glycerol might solidify while out of the processor, the methanol present should keep it liquid and it should stay warm for some time.

Otherwise, stand for a further 20 minutes, and drain off any further glycerol present, leaving just biodiesel ready to settle or filter.

After extensive testing it has been found that first stage catalyst of 3.5g/l for NaOH or 5g/l KOH give good results. Adjust the levels of catalyst to get around 60 to 75% conversion on the first stage, this will ensure you are producing as little soap as possible while being able to achieve a good pass with two stages.

It seems that most of the people who have been trialling this method are getting around a 25% reduction in catalyst use and much less soap produced in the process. It has also been reported that some people are getting more biodiesel out than WVO put in."






 
Location: ลึก ประเทศอินเดีย | Registered: March 03, 2001Reply With QuoteReport This Post
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Thanks for everyone's commenets the actual problem was my electronic scale was incorrect, it indicated half of the actual amount thus I ended up using more than double the amount of catalyst. My second batch base/base reaction produces 100l of glob glycerin soap.
 
Registered: March 24, 2015Reply With QuoteReport This Post
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