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How To Make Biodiesel

Imagine keeping the farm fuel tanks full without ever seeing a delivery truck. That situation could be a reality for many prairie farmers, particularly those who can turn oilseeds into biodiesel.

How much money would that save every year? Rex Newkirk, director of research and business development at the Canadian International Grains Institute, says there are some input costs associated with refining fuel on the farm, but it is possible to see some savings. Exactly how much depends primarily on the cost of the base oil.

“For on-farm production you’re looking at about 17 cents per litre when making 1,000-litre batches,” he says. “On top of that you have the cost of your oil.” With a small, commercially-available press designed to squeeze the oil out of oilseeds, the base oil could come right out of a farm bin. For anyone with poor quality oilseeds in storage, such as heated canola, this could be an ideal way to get maximum value out of it.

But before picking up the phone to order a press and refining equipment, farmers need to know how to do it properly and safely. “Not only is quality important, but there is a safety aspect,” adds Newkirk. “Methanol is really flammable and toxic. I can’t stress the safety aspect enough.” (Methanol is used in the refining process). With some basic safety precautions and a good understanding of the process, the risks can be easily managed.

To help people learn the correct process, CIGI’s trailer with an onboard refinery travels the prairies

to hold one and two-day training seminars, leaving students with the basic skills and knowledge to make their own biodiesel. According to Newkirk, the students range from farmers with no previous bio-fuels experience to training staff at small, commercial biodiesel refineries.

HOW TO MAKE BIODIESEL

For anyone who didn’t make it to a seminar in their area, here are the basic steps.

To begin with, find a suitable spot to set up the refinery. “(Set ups) on farms are typically looking at buying an old semi trailer, something that stands alone and they can put the (proper) ventilation into it,” says Newkirk. And while many companies are selling small refining systems designed to fit into the garage attached to a city home, Newkirk says that isn’t the best situation from a safety standpoint. “You’ve got to do this carefully.” Keep it out of inhabited buildings, he says.

The raw oil coming out of a press is too thick for most diesel injectors to handle. It’s best to convert the oil to biodiesel.

Next, find a suitable oil source. Which one is best? Newkirk says one of his students recently asked him that very question. “I said, whatever I can afford.” The point here is to keep economics in mind. Canola has good properties for making fuel, but it isn’t always cost effective.

If farmers want to use seed from the bin, they’ll need to have an expeller press to extract the oil. “There are a number of these on the market. There are all kinds of suppliers,” says Newkirk. “On the farm we’re typically looking at a one to four tonne-per-day press.”

Of the options available, the

It is kind of a complicated thing and it’s a challenge, but it’s the coolest thing to

be driving my truck down the road on fuel we made yesterday

Komet style is simple and effective but tends to be a little more expensive. Newkirk believes it is the higher-quality option and works best. Along with oil, the press will create oilseed meal as a by-product, which can be used as a high-protein livestock feed supplement. That adds additional value to the process.

THE REFINING PROCESS

The raw oil coming out of the press is too thick for most diesel engine injectors to handle, even though it can be used as a fuel in that state; and some special systems can be installed on an engine to accommodate it. “Fuel has a weight (viscosity) of two, while vegetable oil has a weight of about 40, making it similar to engine oil. Your engine (fuel system) is really not designed for that kind of viscosity,” says Newkirk.

Converting that raw oil to biodiesel involves a process called transesterification, a chemical reaction breaking the long molecule chains that make the raw oil for about an hour at a temperature of 55 C. That removes the glycerol molecules and lowers viscosity.

The mixture is left for another hour, allowing the separated glycerol to settle to the bottom of the tank. The glycerol component amounts to about 14 per cent of the oil’s overall volume.

Using a larger amount of alcohol than necessary allows the reaction to occur faster. And the extra alcohol is recovered using the same process involved in an old-fashioned whiskey still. The reclaimed alcohol (methanol) is then held in a second tank, which is stored in a separate area to minimize the risk of fire and dangerous vapours.

The remaining fuel is transferred into a another tank for a water wash to remove impurities and any remaining glycerol. A spray nozzle at the top of the tank mists water over the fuel. The droplets attach to impurities as they settle to the bottom. “For each gallon of fuel we use a gallon of water,” adds Newkirk. “It really should be good quality soft water.”

— Rex Newkirk, Canadian International Grains Institute

raw oil so viscous. It uses an alcohol-based catalyst, which removes the glycerine molecule from the chain and allows the resulting biodiesel to flow much easier.

The process starts by testing the raw oil for fatty acids. Depending on the results from that initial test, a blend of methanol and lye is mixed together in the proper proportions to create a catalyst. (When refining an 80-litre batch of oil at the Saskatoon seminar, students blended in 600 grams of lye mixed with 17 litres of methanol as a catalyst.) That, along with extra alcohol, is mixed with The water is then drained off, and the fuel is passed through a resin tank to capture any remaining traces of it. From there the fuel goes through an ordinary filter and the process is complete.

TEST THE FINAL PRODUCT

But Newkirk says following that up with a testing procedure will confirm the fuel has a high quality and there are no remaining impurities. “Even on the farm where you’re just using the fuel yourself, it’s important to ensure you’ve done the job well.”

Having a commercial lab do all the necessary tests to confirm the fuel conforms to ASTM standards will cost about $1,500. “But that’s (only) for sale,” says Newkirk. “A number of those tests have no meaning to the actual user. But there are some key things you have to do to ensure your fuel is safe.” Those tests can be done on the farm.

They begin with testing for the presence of bound glycerine, which involves taking a small fuel sample and mixing it with methanol to see if anything settles to the bottom. If there is no reaction, the refining process is complete.

Next is a viscosity test. This involves putting a sample of fuel heated to 40 C into a special cup to see how long it takes to flow out. A water and sediment test is done by putting a tube full of fuel in a small centrifuge to see if anything comes out of solution after spinning it. The testing process is finished off by measuring the acid level through a simple titration method. That ensures there are no residual minerals remaining.

If the fuel fails any of these tests, the process hasn’t been a waste. It can simply be reprocessed until it passes.

While all this may sound pretty involved, each step involves nothing more complex than some basic high-school chemistry. Taking the CIGI course will leave students primed and ready to refine their own biodiesel on the farm.

“It is kind of a complicated thing and it’s challenge,” adds Newkirk. “But it’s the coolest thing to be driving my truck down the road on fuel we made yesterday.”

To check for upcoming biodiesel making courses, visit www.cigi.ca

Scott Garvey is machinery editor for Grainews. He’s saving his french fry oil to fuel his farm truck. Contact him at [email protected]

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Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.

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