Make Your Own Biodiesel Processor




About: Ask me questions. I know the answers.

In a world where environmental awareness is becoming increasingly important for individuals, businesses, and mankind as a whole, it's always important to be looking for ways to re-use waste and cut carbon emissions. Biodiesel is a great way to do this. You're reusing waste oil and reducing your impact on the environment.

This Instructable will take you step-by-step through the process of making a BioDiesel processor. This type of Processor is called an appleseed processor. It uses an old (or new if you feel like dropping the money) water heater. The amount of fuel you can make will depend on the size tank you use. My first prototype uses a 10 gallon tank. Not too efficient if you plan on making large quantities, but great for figuring things out.

Before you do this project you should research the process and dangers involved in producing biodiesel at home.

Before you run out and buy $100+ worth of plumbing materials, I should say this: As biodiesel becomes more and more popular the resources available become more and more scarce, and people are starting to charge for things that used to be free, specifically Waste Vegetable Oil (WVO). I would suggest securing a source for WVO before you embark on this project.

There are many unspoken rules about gathering WVO from businesses, and I can talk about those in another instructable. For now just know that you CANNOT just take oil, for this you can get arrested and tried. You also need to be consistent (If you say you'll be there every Tuesday to pick up someone's oil and you show up on Wednesday half the time people will often give your oil to other people).

My instructable on how to use this processor can be found here.

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Step 1: Do Some Research

Do some research. You can't read too much about biodiesel. I spent about a year researching before I built this and started making fuel.
A book that is a must read is Biodiesel Basics and Beyond: A Comprehensive Guide to Production and Use for the Home and Farm Much of the information you find on the internet (including this instructable, no doubt) is incomplete information. This book will give you the ins and outs of every step you need to take.

Be familiar with how the process works before you build a processor. If you understand how it's supposed to operate when it's finished, you will make fewer mistakes when you're building it.

Step 2: Plan

Plan, plan, and plan some more. You can't get too detailed in your planning. Map out every part you'll need, list the functions of every part, and estimate costs. Nothing would suck more than getting half way through and realizing you're out of money and you've just blown $130 on half a processor. We made the trip to Lowes about 9 times before we had everything we needed.

Here's some pictures of our planning process, but only a fraction of it; we probably drew this diagram in a dozen ways a dozen times.
Tip: Black boards and white boards come in handy, like mine, when you;re trying to get a feel for what you need. Things erase easily and you get a larger diagram to concentrate on.

I will include some more detailed diagrams of what we did here soon.

Step 3: Aquire the Necessary Parts

You will need a water heater, a pump, and all the plumbing in between. I used a 10 gallon water heater and a 1" water pump from Northern Tool.
Be sure that the water heater does not leak and has a working heat element. The element is very very important since you will be heating the oil up prior to making the fuel. You will also want to keep it warm when it settles, in addition to when you remove the glycerin.

You will need about ten feet of 3/4" clear PVC flexible hose. (+hose clamps)
The plumbing materials I used were:

-3 tee Joints 3/4" x 3/4" x 3/4"
-2 3/4" Unions (these are so you can disconnect your pump without disassembling the whole thing.)
-2 1"-3/4" reducer couplings
-1 3/4" 90 degree elbow
-7 3/4" Ball valves
-11 3/4" x 1.5" male connectors
-1 3/4" x 2" male connector
-2 1" x 1.5" male connector
-4 3/4" to 3/4" Male adapters (Barb to MPT)
-2 to 3 lengths of 3/4" pipe (this depends on the size of tank you're using. Lows, the one by me anyways, will cut and thread piping for free. Measure twice, so you only have to pay once.)
-You will also need tape to seal each fitting.

You're going to need some way to secure your processor. We used some adjustable straps and some connectors. Certainly you can secure it however you like, but this best suited us since we plan on replacing the tank very shortly.

One other thing you'll need to get acquainted with are carboys. You can some good ones here. You need one with a cap that has a 3/4" female threaded port. This will make your methoxide mixing tank, so you will want it to be air tight.

Lastly, you will need 2 power cords. Or just one if your water heater is already wired.

Step 4: Start Assembling

Start putting it together. No doubt you will have leaks the first time you run water through this, so don't tighten things so tight you won't be able to get them apart again.

Start with the bottom of the processor. First attach a ball valve and work your way to where you'll put the pump.


The three places you use the Tee joints are essentially identical, so I recommend assembling these before you put them on the rest of what you have. From the tee- connector-> Ball valve->Barbed adapter

Then it goes--Ball valve-> Connector-> Tee joint (assembled)-> connector-> Ball valve-> Connector-> Tee joint (assembled)-> Connector-> Union-> Connector-> Reducer coupling-> 1" Connector-> Pump-> (now heading up)-> 1" Connector-> Reducer coupling-> Connector-> Union-> connector-> Tee Joint (assembled)-> Connector-> Ball Valve-> Pipe (length depends on how tall the processor is)-> 90 degree elbow-> Pipe back to processor (again, the length depends on how far it is to the processor)-> Malleable coupling-> and you're back!

Be sure to have the unions disconnected when you assemble the upper part, then connect them again to put the pump back on.

This is a good point to start thinking of what to mount it on, and where. Keep in mind you need a place to drain glycerin below the processor, so you'll need it raised some.

The last piece to assemble is the carboy lid. Drill a hole where you're supposed to and screw in the connector. Onto this, add a ball valve and the fourth hose adapter.

Be sure that your carboy has a vent behind the handle, and be sure this vent is drilled out.

Step 5: Wire It All

Go ahead and wire your pump. A wiring diagram should be included.

Wire the Water heater, the next step is testing the element.

Step 6: Pressure and Leak Test.

Now that you've got it assembled you need to do a pressure test. You can use an air compressor or you can run water through it, which is what we did.

Reasons for pressure testing:
-test for leaks
-gives you an idea of how to use the valves to get liquids where you want them
-to test the heating element
-to be sure everything is facing the right direction (the first time we hooked it all up the pump was facing the wrong way... oops)

Fill a carboy with water and connect a section of hose from the carboy to the intake valve. Use hose clamps to secure the hose. Be sure to have primed the pump.
Now open the valve on the carboy and the intake valve. Turn on the pump and make sure the glycerin drain and out-take valve are both closed, so water doesn't come shooting out. Also be sure that all the valves in the circuit are opened so you don't have any pressure building up. At this point it is very important to have the pressure vent on the tank open.

Mark where you see any leaks with a sharpie.

Go ahead and turn on the heating element, it may take a while to heat up. Mine didn't, 7 gallons of water takes just a few minutes to get hot. You can open the out-take valve whenever you like to get a sample of the water. Be careful, though, we're talking hot water here. You can test it with a quick-read thermometer.

When you're finished, close the valve nearest the tank and let the pump run a few more minutes before you turn it off. There's still some water behind the pump, so open the glycerin drain to drain off the cup or two of water left.

Close the next valve over from the drain and open the first valve. Have something to catch the water as it comes out.
It's probably still hot, so be careful depending on how hot you got the water.

One more thing. After testing all this be sure to open up every connection and let it dry. You don't want a drop of water in there when you make your fuel.

Step 7: Mount It

Now it's time to mount it. You may find it useful to disconnect the pump at the unions when you're moving it around. You can mount it however you want, and it doesn't have to be able to move, but you do want it raised some so you can drain stuff.

We mounted ours on an existing wooden box, just because we had it. We just took some plywood, screwed some 2x4's onto that, and attached some wheels to the 2x4's. Two of the wheels are locking,so it won't roll down my driveway, slide around, or generally escape us.

We screwed the pump into a board on top of the box and used adjustable straps to secure the tank.

In my next Instructable I will explain how to use this processor. In the mean time, build one!

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    106 Discussions

    Paul TJ

    2 years ago

    Using bio-diesel in modern cars with electronic injectors and common rail systems is not recommended unless the manufacturer OKs it. I run my bus on 25% vegetable oil added to ordinary diesel, the engine is a Cummins B series 8.6 litres. The problem with bio-diesel made from waste cooking oil/vegetable oil is that it forms a deposit in pipes, fuel filter, injector pump and injectors. This can be prevented by occasionally emptying the fuel tank, refill with proprietary diesel to which add 5% methanol. I do this every 10 th fill to be sure.


    2 years ago

    Hi There

    Great project! I just wanted to point out that there are certain materials that should be avoided in a bio-diesel processor or handling/storage equipment. Brass, bronze, copper, lead, tin, and zinc may accelerate the oxidation process of bio-diesel creating fuel in-solubles or gels and salts. Lead solders and zinc linings should be avoided, as should copper pipes, brass regulators, and copper fittings or tanks.

    I guess if you are just making a small rig to test out the process this maybe fine but for a long term unit it would be best to avoid the above materials. It is also worth doing a little research on plastics and elastomers used for example in pump seals etc to make sure they will not be adversely affected resulting in catastrophic failure.

    Keep up the good work :-) This kind of project inspires us all.


    11 years ago on Introduction

    yo man whats up!!! i like how you made your bio-diesel processor here is a picture of my processor i make with my dad. i can make 20 gallons at a time!!!! i also have alot of good web-site's to help you with any problems you have i'll give you a web-site they have alot of cool pic's all about bio-diesel

    5 replies

    Reply 2 years ago

    I am making a biodiesel fuel processor for a project in school and need a step by step process on how to make it with pictures preferably. I don't even know where to start please email me at


    Be very careful with a poly processor. I have a friend in Mololla, Oregon, who burnt down his barn (and $20,000 worth of solar panels) when the processor heater melted the poly tank, which then ran out, causing the heating element to explode and ignite the biodiesel, which then ignited the methanol stored on site.

    Thinks can get out of hand VERY QUICKLY! I strongly suggest avoiding the combination of plastic tanks and electric heating elements. You can use a poly tank processor ONLY if you use hydronic heating that well NEVER get hot enough to melt the tank!


    Reply 10 years ago on Introduction

    Steven, I like your system. Is it possible to obtain a step by step schematic of your entire processor? Thanks, Jim


    3 years ago

    One thing to point out, is that you should never pressure test and the enclosed vessel with air other compressible gas, because you are essentially creating pressure bomb. You should use a fluid like water or something that is not impressed because the system will either only week, or if it bursts open it is not as dangerous.

    1 reply

    Reply 3 years ago

    correction ... Water or something that is non-compressible ...


    3 years ago

    Hi, can you use a copper hot water tank as I have 2 spare 280L units?


    3 years ago

    I read the whole first section in movie trailer announcer voice. In a world where... lolz


    4 years ago

    You need to lay out all the parts you used side by side and tagged for extra info


    4 years ago on Introduction

    Good article but if any more want to know more about biodiesel Processor can visit the below given link.

    Matt D655

    8 years ago on Introduction

    Bio-diesel is very useful. They even have bio-diesel heaters.


    It is possible but you should never try it. The only way it will work is if the car is to full temp and diesel is added it the tank but when it cools there is no chance of starting it till the tank and fuel lines have been drained and the fuel injectors are cleaned. (That all refers to dino-D but should be about the same.)

    Do not try running any Diesel on a gas engine.


    10 years ago on Introduction

    where do i get a water heater. is it assumed that i have an old one lying around. thanks, nolan