Putting it all Together

Math
So, we just made 1 liter of biodiesel. Now it's time to see if this is something that can save us money- that's one purpose of this project- to see if replacing some our weekly fuel consumption with what we just did will lower fuel costs. Let's start off by figuring how much our biodiesel costs to make:

Our bottle of Heet cost $2.29 for 355 mL, so that turns into $1.29 for the 200 mL we used.

The bottle of Drano cost $5.78 for 510 g, that turns into about $.06 for the 5.5 g we used.

The vegetable oil was $2.50 for the 1.42 L bottle, which turns into $1.76 for the 1 L we used.

Adding this up makes our biodiesel cost $3.11/L or $11.78/gallon!

Clearly, this is not a viable economic choice at all. So, now what? Can this be economically feasable? Perhaps on a large scale. Looking aroung on the internet, I found a purchasable large-scale (relatively speaking of course) biodiesel reactor from Northern Tool for the price of $3500.

This is an 80 gallon capacity batch processor- so we can make up to 80 gallons of biodiesel at a time. Now, we need to figure out how much to scale up our chemical raw materials. I'll spare the nitty-gritty unit analysis, but to make 80 gallons of biodiesel, we'll need roughly:

17 gallons of methanol

80 gallons of vegetable oil

~2 kg lye

I was able to find prices for the methanol and lye in bulk from Oakwood Chemical Products (http://www.oakwoodchemical.com/). Unfortunately, I found that vegetable oil only comes in sizes of 1-10 L or sizes on the scale of 1 metric ton (1000 kg). So, I figured that investing $3500 in a biodiesel maker, we'll be making a lot more than just one 80 gallon batch. Re-scaling everything to make 1 metric ton of biodiesel (using 1 metric ton of oil as the basis- or ~320 gallons), and using prices from Oakwood, our raw materials will cost us:

$480 for four 18 L jugs of methanol at $120 each

$110 for a 15 kg container of lye (we'll only need ~8 kg, but there's not a big choice in size here)

and $1000 for the oil (metric ton)

This leaves us with a fuel cost of $1590/320 gallons, or $4.97/gallon. That is a lot more economical, but we're not including the whopping $3500 up front cost to make this. Including that in our calculations for 320 gallons makes our biodiesel cost $15.90/gallon! Ouch! That's even more expensive than the home-brewed variety we made. 

Something that is very important to understand now, is that most diesel engines can only handle around 20% biodiesel. So our 320 gallons would be good for around 1,600 gallons total. If we have a Volkswagen Jetta that holds 15 gallons in its tank, and averages 40 mpg, our 320 gallons of biodiesel would last us around 64,000 miles! Most people only drive around 10,000 miles a year, so 320 gallons of biodiesel would last us over 6 years! Since biodiesel is, well, a bio-based fuel, there is some serious breakdown and deterioration of the fuel over the course of 6 years. 

No matter how we slice it, on a backyard/garage-sized setup, we wouldn't be able to make biodiesel less expensive than regular diesel that currently costs $3.98 on average in the Midwest (http://www.eia.gov/petroleum/gasdiesel/).

Conclusion

Well, we learned how to make a biofuel known as "biodiesel" which is really just a (slightly) complicated class of organic molecules known as fatty acid methyl esters. It's really simple to do, and can be done with household products. Economically, this process is not viable- for now. This is a classic example of where the chemistry is pure awesome, but the real-world economics say, "I don't think so." 

The whole concept of biofuels leaves plenty of room for improvement- one of the big downfalls is figuring out how to make stuff like biodiesel and corn ethanol for a fraction of the current cost. That's why it takes teams of research scientists to figure out processes for making biofuels, and engineers to figure out how to make it big and cheap. I hope you followed along in this series of posts, and that you learned a thing or two about biofuels. Thank you  also to Paige Hancock, who assisted with picture-taking and moral support. Finally, thank you to Professor David Schmidt who assigned this project and helped me learn a plethora of things in the process. Now, go out and make a gallon or two of biodiesel! Or better yet, switch to an engineering major and help figure out how to make a billion gallons! 

-John Hancock

Separation/Purification

Separation
So, I left off with the freshly-made biodiesel suspended upside-down so the glycerol and actual biodiesel could separate. This is what it should look like after 24-48 hours:

Separated mixture of biodiesel and glycerol

As you can see, there are two distinct layers. The top is our product- biodiesel. The bottom layer is our glycerol, which we can dispose of. Glycerol is soluble in water, and harmless. We can drain the bottom layer out by unscrewing the cap slightly and applying pressure to the bottle- squeezing a little biodiesel out as well (now you understand why I stored it upside-down- I'm not crazy!). What we will need to do now is something called "washing" the biodiesel. This doesn't mean using Dawn detergent to clean it up- but on the same track. Even though we got most of the glycerol out, there still may be some impurities. This could include tiny amounts of glycerol, bits of dust from the pot and pouring apparatus we used, or even un-reacted lye (NaOH). Basically, anything that's not an organic molecule needs to come out (OK, glycerol technically is an organic alcohol, but it is water soluble, and we need to get rid of it, so it fits our description). This is done by simply pouring about 500 mL (you don't need to be exact, this is to get rid of impurities, so the the amount you put in doesn't really matter- I've found that this technique throws off lots of budding organic chemists in lab settings) or so of water. Then, mix it up, and let it separate (sit overnight- upside-down again!). After the product is settled, we can do the same procedure to remove the water- drain it out through the cap. If you feel so bold, and want to follow proper lab technique, you can repeat this washing process two more times. Since I'm not planning on actually using this biodiesel as a fuel source (I don't have a diesel-powered vehicle or engine), one washing is good enough. However, I strongly suggest that you wash yours two to three times if you plan on using it for fuel. When all is said and done, we have a low-grade, pure biofuel. Pretty awesome. 

Homemade biodiesel. To quote Bill Nye- "Science rules"

So, to recap, we took vegetable oil, drain cleaner, and Heet fuel additive, and turned it into a drop-in biofuel know as biodiesel. There was some chemistry fun along the way, and we learned some basic organic lab techniques. I always like to reflect on anything scientific that I learn or do by asking myself the following question:

So now what?

Naturally this raises other questions such as, can I eliminate making gas station stops? Can this be scaled up? Is this process economically viable? Will this help USA fuel independence? 

Part of this blog and project is for addressing some of these questions, and doing some math to answer them. That will have to wait until tomorrow, but if you're following along in real-time, see if you can find some answers! In the meantime, I need to crunch some numbers, and we'll talk in my next post about costs of biodiesel fuel, practical concerns, and we can see if this is really a viable option to help solve the renewable energy debate.

Making Biodiesel

Making Biodiesel
Last time, I talked about the raw materials needed for this, and the (very) basic chemistry behind our reaction. Now, we're going to move on to the fun stuff- let's make some biodiesel!

To begin, we need 1 Liter of vegetable oil (above)

In order to have a successful reaction, that proceeds at a decent rate (chemical kinetics is a bit beyond the scope of this blog/project), we need to heat the oil to 130 degrees F.

Heated oil at 130 degrees F

While waiting for the oil to heat, you can prepare the sodium methoxide. This is done by measuring 200 mL of methanol (Heet) and adding ~5.5 g (capfull) of NaOH (Drano/lye). I did  this by pouring the methanol into a glass home canning jar, and then adding the NaOH.

~5.5 g lye (NaOH)

Adding NaOH to methanol

You want to make sure ALL of the lye dissolves. I found that there were some inert compounds that didn't dissolve- I strained those solids out using a small-holed colander (don't use it for food preparation afterwards!). During the methoxide reaction, it is important to be in a well-ventilated area. There won't be any seriously toxic gases given off, since we're dealing with small amounts, but it is always good practice to have a kitchen fan on and a few windows open. 

After the oil is heated up, it is time to pour it into the mixing (and later separating) vessel (above). Make sure to use a funnel so you're not spilling hot oil and/or sodium methoxide all over the place.

Adding the sodium methoxide to the heated oil

Here is where the chemical "magic" happens- You can see the liquids are slightly miscible, and bubbles are forming. This is good- it means the reaction is going! After all the liquids are poured, it is time to mix.

Mixing. And shaking. Like a salt shaker.

You'll want to shake the mixture for a good 5-10 minutes. This will ensure a thorough reaction, and that most of the oil/methoxide will go to completion (that means almost all of it will react- we want that). After this is done, store the vessel cap down and let it sit for around 48 hours (using a glass to balance works great) so it can readily be separated.

Now What?

Now, you have made a very crude and impure one liter batch of biodiesel! Something that is important to understand (and helps explain why we'll need to separate the mixture) is that the reactants ("ingredients") made the product (biodiesel) that we wanted, but also something called glycerine (also known as glycerol). Basically, when the methoxide breaks apart the oil (lipid) molecules to make the fatty acid methyl ester (see previous post for more chemistry talk), the "backbone" portion doesn't just disappear, and it becomes glycerine. We'll need to separate this from our biodiesel, so our new biofuel will be less crude, and more pure, which means it will run better in our diesel engine. But for right now, we'll need to let it sit so the two liquids can separate. 

What is Biodiesel?/Getting Started

What is Biodiesel?
Biodiesel is a "drop-in" biofuel that is "clean burning and renewable" (http://www.biodiesel.org/) and can be used to power and supply current diesel engines with fuel. Currently, the US Department of Energy  mandates a 5% biodiesel blend for all diesel fuels sold at gas stations in the state of Minnesota (http://www.afdc.energy.gov/laws/law/MN/5452).
What this means is that there is potential for a clean, renewable fuel source made from completely domestic and renewable sources. "Drop-in" means that you can pour some biodiesel directly into your diesel tank, and your vehicle will run- pretty cool, eh? Most diesel engines aren't designed to run completely on this stuff, but it is completely safe and plausible to cut fuel costs (watch for this post a bit later) by making a few liters right in your kitchen.
On a more complicated, chemical level, biodiesel is really just a fatty acid methyl ester, which is easily made using household products:
Vegetable oil will give the backbone of the chemical formula for biodiesel. Vegetable oil is actually composed of a mixture of triglyceride oils (fats) that are similar in chemical composition. When these oils come into contact with a compound called methoxide, a strong organic base, the triglyceride bonds are broken, and are re-formed with methoxide, creating a fatty acid methyl ester.
Methoxide is not found readily at Cub foods or Wal-Mart, so we'll have to make it ourselves. This is done by mixing methanol (found in Heet fuel additive) with an equal amount (molar ratio) of NaOH- sodium hydroxide- otherwise know as lye. You can find this in the popular drain cleaning agent Drano. An important note is that this needs to be 100% NaOH solid drain cleaner. If not, other side reactions can occur that aren't too safe!

Getting Started

Materials and safety ware

The above picture shows what you will need to make your own biodiesel:

Safety goggles/glasses

Gloves

Funnel

Measuring containers

Thermometer

Plastic Bottle (for mixing)

Glass Jar (for heating oil)

Vegetable Oil- 1000 mL

Methanol (Heet)- 200 mL

NaOH (Drano)- 5.5 g

Water

Heat source (stove)

As you can see, everything is easily found at an all-around store like Wal-Mart or Target. Even most grocery stores will have most, if not all, of the necessary materials/ingredients. Safety is always the number one issue, so ALWAYS remember to work in a well-ventilated area with proper safety equipment.

Now, it's time to begin!