If you’ve been making Biodiesel for a while, you probably know all about Titrating oil and how important it is. Since we’re just at the start of the new brewing season we figured it was time for a refresher course on this important topic.
What Is A Titration?
A Titration is nothing more than a set of steps used to figure out how acidic oil is that you want to use to make Biodiesel. The reason we need to do it is so that we know how much catalyst (NaOH – Lye, or KOH – Potassium Hydroxide) to add to our methanol to make Biodiesel.
How Does It Work?
Titrations work by neutralizing the acid with a strong base. It’s basically the same thing that happens when you make a volcano out of baking soda and lemon juice. The acid and the base neutralize each other.
In the case of titrations though, we have oil with an unknown amount of acid in it so we add measured amounts of base (our titration solution) to it and use a pH indicator (Phenol Red, Phenolphthalein, or Tumeric Powder) to tell us when the acid has been neutralized.
Want to learn more? Check out this video we made explaining titrations!
Video on how a Titration works
Why Do A Titration?
The reason titrations are so important is due to the fact that free fatty acids in oils will neutralize the catalyst into soap. This is bad because if too much of the catalyst gets neutralized then there’s not enough catalyst left to react the oil into Biodiesel.
To deal with this, we measure just how much acid is in the oil by titrating it so that we can add enough EXTRA catalyst to
A) Neutralize the acids in the oil and
B) Still have enough left to react the oil into Biodiesel and
C) Not add too much catalyst, which is both wasteful of an expensive chemical but more importantly, if you add too much, you could react the whole batch of oil into soap. Not fun!
So What Happens If You Don’t Add Enough Catalyst?
The acid in the oil begins to attack the catalyst FIRST and neutralizes a big chunk of it into soap. The left over catalyst then attempts to start reacting the oil into Biodiesel, but now there’s only so much to go around and a lot of oil molecules don’t ever have a chance to get reacted.
Long Answer Short:
You get left with unreacted oil in your Biodiesel. Not good since the goal is to convert the oil to Bidoiesel
How To Do A Titration
So, now that we’ve talked about what it is, how it works, and why you need to do it, let’s talk about how to do it. Titrations are simple! First you’ll need to make up some titration solution
Titration Solution Recipe
1 Add 1 liter of distilled water to a container
2 Measure out 1 gram of catalyst & add to the same jar
3 Shake it up until the catalyst is dissolved
Click here to see a video on making Titration Solution
Performing The Titration
1 Put 10 mL Isopropyl Alcohol in a small vial
2 Add 1 mL Oil to be titrated
3 Add 2-3 drops of pH Solution (Phenolphthalein, Phenol Red, Turmeric)
4 Shake it all up
5 Slowly add in titration solution until it turns color
6 Measure how much titration solution you added and record it
– This should be recorded in Milliliters
– This becomes your “titration value”
7 Do this 3 times and average the titration values together
Click here to see how to do an actual Titration
Click here to see another video of doing a Titration
If NaOH, you’ll use a base of 5.5
If KOH, you’ll use a base of 7
Now, divide the base for your catalyst by how pure it is.
For example, if your KOH is 90% pure, then it would be 7/.90 (or 7.8).
The Titration Calculation
(Base + Amount used in step 6) x liters of oil = grams required
50 Gallons of oil to be reacted into Biodiesel
Titration from step 6 was 5 milliliters
Using 90% Pure Potassium Hydroxide for your catalyst
Calculate the base. 7/.90 = 7.8
Calculate gallons into liters. 50 x 3.785 = 189.25 liters
Calculate the titration
(7.8+5) = 12.8 grams per liter
12.8 x 189.25 = 2422.4 Grams Required
I always round up, so the total grams of KOH required will be 2423.
Here’s the formula in a quick & dirty format:
[(B/P) + T] x O = Grams of Catalyst Required
B = Base Amount
P = Catalyst Purity
T = Titration Value
O = Oil In Liters
There are 3.785 Liters in 1 gallon.
Check out this great video on titrating oil!
Want To See More On Titrations?
We’ve created several video’s on titrations
Video On Building A Titration Kit
Video Explaining The Chemistry Behind Titrations
Video On Making Titration Solution
Video On Performing 3 Titrations
Need A Titration Kit? We’ve Got You Covered!
We carry 3 different Titration kits that can get you started with the right equipment in a hurry. Be sure to check them out today!
Link To Basic Titration Kit
– This kit adds everything needed to do a basic titration with. You just add isopropyl alcohol, oil, and distilled water.
And now you’re all set! Get out there & start titrating!