What factors contribute to high yield?

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello Troy
I could see that my first post was confusing as I used the work Biodiesel to mean Methyl esters.
If you think it was wrong that is fine with me
I am glad you now understand my edited version.
If you wish to participate on a home brew biodiesel forum is probably better that you learn the language than expect everyone to change to your way of talking..

Perhaps this explanation by Neutral on the Infopop Forum will help you to understand better.
"Yield is the amount of product divided by the amount of starting material
Conversion is the proportion of methyl ester in the product."

It is so simple when you read it that way. I can not recall Neutral ever having a problem understanding the difference between yield and Conversion.
Perhaps that was because he has a PhD in chemistry.

I do not understand the blond joke. What is a 710 cap?

[TroyH Senior Member Find all posts View Profile Close TroyH]

Re: What factors contribute to high yield?

Perhaps you should go and read what neutral said again. since it is not what you were saying, and is very close in fact, to what I said.

the definition I gave for yield, is the same as what neutral gave (go on, click the link.) only I made reference to what was being considered product.

When neutral says "Conversion is the proportion of methyl ester in the product." it means the same thing as proportion of oil converted to ester, rather than to something else (although strictly all alternative reaction products should be considered. neutral hasn't done that.). Think about what the actual word conversion means for a minute.

The only thing really that would change anything, is if you only consider esters to be your product, of if you consider the entire organic layer to be product. Neutral here is referring to yield in terms of the entire organic layer being a product, but conversion in terms of the methyl ester being product. if he was talking about yield ONLY in terms of methyl ester, the conversion and the yield would be the same thing.
This is why I say it is subjective.
There are times when you can have a low yield, and a high conversion, but this is when not all of your feedstock is consumed. If all of your feedstock is consumed, the only way you can have a high yield, is if you have a high conversion (provided you are referring to the same chemical when you talk about conversion and yield).

i.e. 20% of your feedstock reacts to form products, and 100% of your product is what you desired, then you had 20% yield, and 100% conversion. However, if you had 100% of your feedstock reacts, but only 20% is converted to your desired products, then both your conversion and your yield are 20%.

There is nothing wrong with the terminology, only your use of it, and possible misinterpretation of what neutral says.

you said something along the lines of "high conversion = low yield, and low conversion = high yield." which is not the case. That is what I was referring to as being wrong and confusing.

I hope this clears things up.


edit: OIL upside-down reads 710. the blonde and the mechanic were talking about the same thing, but she was using her interpretation of the name on the cap. Which was of course incorrect. The mechanic is hardly going to start using the term "710 cap" to describe the oil cap, as it would not make sense.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello Troy
I understand the difference between Yield and conversion
You seem confused.
Perhaps this post by Neutral will help.
yield (quantity of product)
conversion (purity of product).

As for increased yield with lower conversion these posts by Neutral might help.
Neutral said
"If you go back through the posts on this forum you will find one which states there is a tradeoff between yield (quantity of product) and conversion (purity of product).
If you use the Tickell amount of NaOH (3.5 g per litre plus titration) you will fall short of getting the ASTM figure for conversion but you will usually get a good yield. If you use 5g NaOH plus titration you should reach ASTM standard for conversion and the yield will be reduced, but so little that you would never notice it in a backyard batch."

Another post
Remember that there is a trade off between conversion and yield. Very high conversion occurs with 5g NaOH plus titration, but max yield occurs with a little less.'

When I did some testing I could easily detect the difference in yield between a high conversion batch and a low conversion batch

If you still are unclear you might want to go to the infopop forum and do an advanced search using the words yield and conversion with neutral as the author. Lots of posts

[TroyH Senior Member Find all posts View Profile Close TroyH]

Re: What factors contribute to high yield?

Tilly, I am not unclear on the meanings. In fact, I often have to use them when writing reports to be graded by...funnily enough, an organic chemist with a PhD who is also an Associate Professor.

What neutral is saying there, is that to get astm standard fuel, you need to convert to esters, rather than mono or diglycerides. Since in the first instance (using Tickell quantities) the mono and diglycerides are counted in the yield value, the overall yield is high. The yield of ester, isn't (as conversion isn't).

In the second instance, the yield of ester is about the same or higher, as the conversion is higher.

He is describing circumstances that result in higher TOTAL yield with incomplete conversion to esters, or lower TOTAL yield with more complete conversion to esters(I would suggest it is related to the formation of water and the formation of the catalytic species). He is not saying that the ester yield is higher in the incomplete conversion.
You are once again trying to take something neutral said in a specific example, and use it out of context in an incorrect sweeping statement.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello Troy

You really sound confused.
I am telling you of my own experiences which oddly enough are the same as neutral's experience.

In my experience High conversion biodiesel typically achieves a lower yield than than Lower conversion biodiesel.

You never explained the blond joke.
.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello Troy

Perhaps this will help you understand.
Lets say I reacted 100 litres of high titration oil and after washing and drying I find that I have 45 litres of fuel.
In Home brew biodiesel talk, my Yield is 45%.

I have plenty of money so I send a sample of this fuel away to have a GC test performed and I find that 95% of the sample is Methyl Esters.
Therefore, in home brew biodiesel talk my Conversion is 95%

That is all there is to it. Do not read anything else into the meaning of these two words when they are used by themselves in home brew biodiesel speak

In home brew biodiesel talk the single word Yield by itself is not directly related to the methyl esters present in the fuel.
.

[gwalker Senior Member Find all posts View Profile Close gwalker]

Re: What factors contribute to high yield?

Hello Troy

Perhaps this will help you understand.
Lets say I reacted 100 litres of high titration oil and after washing and drying I find that I have 45 litres of fuel.
In Home brew biodiesel talk, my Yield is 45%.

I have plenty of money so I send a sample of this fuel away to have a GC test performed and I find that 95% of the sample is Methyl Esters.
Therefore, in home brew biodiesel talk my Conversion is 95%

That is all there is to it. Do not read anything else into the meaning of these two words when they are used by themselves in home brew biodiesel speak

In home brew biodiesel talk the single word Yield by itself is not directly related to the methyl esters present in the fuel.
.

OK! I'm getting close to the question I want to know?

" Lets say I reacted 100 litres of high titration oil and after washing and drying I find that I have 45 litres of fuel."

How many litres of fuel should a home brewer normally expect - 45litres?

ie From 100 litres of VO, how much BD should I expect to be able to pour into my vehicle fuel tank?

George

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello George

Using a single stage base method people typically seem to achieve a yield between about 82%- 92%. I often achieved in the high 80's or better.
The titration is probably the largest reason for variation.

So with "normal" titrating WVO you should expect at least 85 litres of fuel for every 100 litres of WVO you react.

[gwalker Senior Member Find all posts View Profile Close gwalker]

Re: What factors contribute to high yield?

Hello George

Using a single stage base method people typically seem to achieve a yield between about 82%- 92%. I often achieved in the high 80's or better.
The titration is probably the largest reason for variation.

So with "normal" titrating WVO you should expect at least 85 litres of fuel for every 100 litres of WVO you react.

Good morning Tilly,
I haven't seen anything like 82%- 92% in my test batches using KOH. I think I should look for a source of better oil.
George

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello George

What did the WVO titrate.

[gwalker Senior Member Find all posts View Profile Close gwalker]

Re: What factors contribute to high yield?

Hello George

What did the WVO titrate.

Tillly,
This batch titrated at 6.
George

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello George

A titration of 6 KOH is about 3% FFA.
A rule of thumb suggested by Neutral is that for every1% of FFA you will lose about 3% yield. I never actually achieved this good a result, but you should have a yield in the mid to high 80%'s with that titration.
Have you checked for water in the oil?

[marki Senior Member Find all posts View Profile Close marki]

Re: What factors contribute to high yield?

Hello Troy

You really sound confused.
I am telling you of my own experiences which oddly enough are the same as neutral's experience.

In my experience High conversion biodiesel typically achieves a lower yield than than Lower conversion biodiesel.

You never explained the blond joke.
.

Hi Tilly,

Actually, Troy was not confused at all - he was just trying to clarify some of the finer points of Neutrals posts that you had missed.

But anyway - thanks for a most enlightening discussion. It raises a point that I had been wondering about for a while. If I have made a low conversion batch, what are the other things in there besides the ester?
Mono and diglycerides?

And, the $64 question is, does it matter? Presumably these would not be removed at the washing step, and would finish up in my fuel tank. Are there any implications in terms of either their combustion products or their lubricity as far as my engine are concerned.

I ask this because my Injector Pump is being overhauled as we speak, and I have a badly scored timing piston in it. It seems to have simply been a product of normal wear, but nonetheless if compounds other than the highly lubricating ester are in there, I want to know about any implications.
Cheers,
Mark

[gwalker Senior Member Find all posts View Profile Close gwalker]

Re: What factors contribute to high yield?

Hello George

A titration of 6 KOH is about 3% FFA.
A rule of thumb suggested by Neutral is that for every1% of FFA you will lose about 3% yield. I never actually achieved this good a result, but you should have a yield in the mid to high 80%'s with that titration.
Have you checked for water in the oil?

aaaahhhh! I'm still learning what corners I can cut and the ones I can't.
I assumed that the process was more like making concrete than catching a train.
George

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: What factors contribute to high yield?

Hello marki
I actually think I understand most of what Neutral posts.

In answer to your question:
Not considering the methanol, NaOH/KOH, Soap, glycerol and water, I have been told that the things in a low conversion batch of biodiesel will likely be methyl esters as well as mono, di and tri glycerides.
Th glycerine apparently pulls most of the rest of the Gunk out with it.
What the Glycerine leaves behind is pretty well taken care of in the wash.

As to whether low conversion biodiesel matters, most Indirect injection diesels seem to run fine on non ASTM conversion biodiesel. I know mine did and I have never heard of an Indirect inection Diesel being damaged by lower conversion fuel.
On the other hand there is big question mark about some of the newer common rail direct injection engines, but no reports that I know of of actual damage from Non ASTM conversion fuel.
I have also heard on a few occassions of claims of some of the computer sensors being damaged but I do not know the validity of those claims either.

I never filtered my washed biodiesel prior to putting it into the fuel tank, but when I used unwashed biodiesel I would run it through a 5 micron bag filter