Using acetone to aid soap removal

This page is Work In Progress and therefore may not be complete.

The use of acetone to aid soap removal in water washing was something that was first discussed by Nathan and Steve on this forum, testing has been done by Mark.

First test.

Initial test with no acetone

Initial test with 4 drops of acetone

The initial test was done with a 250ml sample. This had already been water washed and had a soap content of 76ppm. It showed a clear 50/50, 4 drops of acetone were added, the test was then shaken and left to settle. It clearly shows more soap has been liberated into the water.

Soap content now tested at 36ppm

Comparason test

To get a more scientific results I did a batch and then split it in half, the 1st half was finished using the standard pump washing method, the 2nd half was finished using the acetone wash method, this way it shows the difference between the two washing methods on the same batch of biodiesel.

These are the ditails of the batch.

200L of oil that had been glycerol pre-washed
Two stage non titration method was used,
1st stage 25L methanol and 800g of NaOH,
2.5ml dropout in 90/10 test,
2nd stage 7L methanol and 240g of NaOH,
clear pass 90/10 test,
after the glycerol was drained 450ml of hydrochloric acid was added to 20L of water, pumped for 1hr. settled for 3hrs, water drained,
this left a yield of 190L of unfinished biodiesel.
At this stage 95L was drained into clean containers to be acetone washed later.

Results

The results of the standard pump washing are as followed.
A titrated soap test and 50/50 were done at every stage.

Wash No1 soap content
Wash No2 soap content
Wash No3 soap content
Wash No4 soap content

Method.

As yet this has only been tested in conjunction with the Water washing Titrated method.

After the acid wash is drained, add 1ml of acetone to every 10L of bio in to 15% (of batch volume) water. add this to the bio and pump for 1 hour.

Turn pump off and let the water settle, this normally take a few hours to obtain a good split of bio and water.

At this stage, after just one wash (remember the acid wash is just for neutralisation, not soap removal) do a 50/50 soap test, if like me you find that this gives a clear pass (water at the bottom is clear and you have a good split of bio/water) you may wish to to a titrated soap test.

I have done a titrated soap test and got a result of 42.56ppm of soap.

I would normally need to do at least 3 washes to get soaps down to this level.

I see no adverse effects of adding acetone to the bio as it's quite a common practice to do this to aid combustion.