Tweet
I've had reason to need to bleach a batch of WVO before esterification with methoxide and just wanted to share some of my findings with others and outline an alternate work around should the requisite bleaching clay be unavailable.
There has been a lot of talk about using magnesium silicate type bleaching agents and some have suggested using talc. Talc is actually a hydrated form of magnesium silicate and is not acid activated unlike the commercial products hence the poor results.
Although it may be possible to acid activated talc I chose calcium bentonite (smectite) type clays because the procedure called for this. The clay I actually used was sold is a thixotrope and had other compounds like alkyl amine tallowates but I disregarded these knowing I was going to treat with concentrated sulphuric acid.
NOTE: There are swelling and non swelling clays, what is needed is a NON SWELLING type clay, although they may actually both be acid activated, the swelling type has a tendency to froth and foam excessively. Not a good idea with conc H2SO4.
Procedure
1. Add 330 g of Ca/bentone clay to one liter of DI water and mix until homogenous.
2. Bring temp up to about 60 C and slowly add conc. H2SO4 equal to 35%
of total solution volume.
3. Increase temperature to between 100 and 120 C and heat for six to twelve hours. CAUTION: MONITOR FOAMING AS THERE MAY BE A LOSS OF CONTAINMENT
4. Filter solution and wash with DI until pH is neutral
5. Oven dry at 100 C for four hours or overnight at 40 C
6. Crush dried filter cake to -75 um, about the same size as a kitchen sieve
And thats it.
All you need to do know is add this to your WVO or meth ester at 10% and heat to 100 C for about six hours, then cool and filter.
All filtering should be done down to about 10 um, anything above this size can wreak havoc on an engine, its like sandblasting it from the inside!
I haven't actually used my home made bleaching clay so I really can't talk about its efficacy (drying as I write this) but I'll update the thread next week (with pics) when I've had a chance to try it out. From all reports though, this recipe should bleach veg oils equally as good as the best bleaching clays on the market.
Lastly none of this work would be possible if not for 250downunder who supplied me with a free 100L waste soy sample and has been more than generous with his advice and expertise in the area of both bio production and bleaching
Happy bleaching all!
Cheers,
bioboy
There has been a lot of talk about using magnesium silicate type bleaching agents and some have suggested using talc. Talc is actually a hydrated form of magnesium silicate and is not acid activated unlike the commercial products hence the poor results.
Although it may be possible to acid activated talc I chose calcium bentonite (smectite) type clays because the procedure called for this. The clay I actually used was sold is a thixotrope and had other compounds like alkyl amine tallowates but I disregarded these knowing I was going to treat with concentrated sulphuric acid.
NOTE: There are swelling and non swelling clays, what is needed is a NON SWELLING type clay, although they may actually both be acid activated, the swelling type has a tendency to froth and foam excessively. Not a good idea with conc H2SO4.
Procedure
1. Add 330 g of Ca/bentone clay to one liter of DI water and mix until homogenous.
2. Bring temp up to about 60 C and slowly add conc. H2SO4 equal to 35%
of total solution volume.
3. Increase temperature to between 100 and 120 C and heat for six to twelve hours. CAUTION: MONITOR FOAMING AS THERE MAY BE A LOSS OF CONTAINMENT
4. Filter solution and wash with DI until pH is neutral
5. Oven dry at 100 C for four hours or overnight at 40 C
6. Crush dried filter cake to -75 um, about the same size as a kitchen sieve
And thats it.
All you need to do know is add this to your WVO or meth ester at 10% and heat to 100 C for about six hours, then cool and filter.
All filtering should be done down to about 10 um, anything above this size can wreak havoc on an engine, its like sandblasting it from the inside!
I haven't actually used my home made bleaching clay so I really can't talk about its efficacy (drying as I write this) but I'll update the thread next week (with pics) when I've had a chance to try it out. From all reports though, this recipe should bleach veg oils equally as good as the best bleaching clays on the market.
Lastly none of this work would be possible if not for 250downunder who supplied me with a free 100L waste soy sample and has been more than generous with his advice and expertise in the area of both bio production and bleaching
Happy bleaching all!
Cheers,
bioboy
Comment