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Bob Armantrout

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Recent posts by Bob Armantrout

Thanks for the warm welcomes everyone!

And for the great questions.
4 years ago

Tony Rupp wrote:When you use a gallon of used vegetable oil, how much bio fuel is created? What is ratio on conversion?



Hi Tony,

In my experience...it depends.

With Waste Vegetable Oil (WVO) collected from restaurants there's usually about a 10% loss through dewatering and settling to remove the particles of flour and fried bits prior to making biodiesel. If you get very clean and dry oil, this loss can be mush less.

It also depends on how degraded the oil is. When oil degrades, free fatty acids (FFAs) are created that depending on the process you use, may turn into soaps rather than biodiesel. WVO from restaurants is typically about 3% FFAs and are lost to most homebrewers.

The short answer is that for most homebrewers, 1 gallon of collected oil turns into about 0.85 gallons of finished fuel - plus or minus 10%.
4 years ago

Jason Vath wrote:I was wondering if Biodiesel is, or could be made to be less polluting out the exhaust.
To me diesel exhaust is unacceptable, way too toxic.



Agreed about diesel exhaust.

As Tel has pointed out, biodiesel combustion results in less particulate emissions as well as lower poly aromatic hydrocarbons (PAHs) which are known carcinogens.

Here's a page and chart that wraps it up pretty well: Biodiesel Vehicle Emissions

Another big benefit of biodiesel over petroleum diesel is its relatively closed carbon cycle - meaning much less net addition to CO2 in the atmosphere. The carbon being released was fixed into the oil by the oilseed plant from the atmosphere - not a one way trip from a fossil fuel deposit that was sequestered in the earth for millennia.
4 years ago

Jeff Lewis wrote:What have you heard about making Biodiesel, from algae? have they made any progress?



Hi Jeff,

I'll state right up front that I don't believe that algae based biodiesel will ever be commercially available on any significant scale.

Lots of progress is being made in academia, making the process more technically feasible. The challenges include developing strains that are high oil bearing, preventing contamination of the algae culture, and developing an efficient process to extract the oil.

The problem is the potential economic feasibility. Algae has been grown for years on a fairly large scale for the neutraceutical market (particularly spirulina) Cyanotech has been doing this on Hawaii Island for quite some time. The fact is that the neutraceutical market can pay a much higher price for the output, with much less capital invested that it would take to isolate the oil and turn it into biodiesel.

It's a "food vs fuel" play, and food will always be able to support a higher price for the output in my opinion
4 years ago

Wes Cooke wrote:So, what are the pros and cons of WVO vs biodiesel, from an entirely DIY standpoint? My preliminary thoughts... there seems to be a fair amount of the preparation that is similar. Whatever is collected has to be filtered, heated, dewatered, etc. There are obviously some additional steps in making the biodiesel, so I can imagine that the process would be a bit more time consuming.



Hi Wes,

I think you've summed things up pretty well.

Vegetable oil is more viscous than diesel so the fuel needs to be thinner in order to atomize properly on injection and reduce wear on the fuel pump.

Running SVO is modifying you vehicle - running biodiesel in modifying the oil. Both can and are being done successfully by many people worldwide. It really boils down to your personal preference and abilities. I really don't like wrenching on my car, and also am not overly fond of collecting and de-watering oil, so I prefer to buy commercially produced biodiesel from my local small-scale biodiesel plant. There's no right answer that fits every one - just what works for you.
4 years ago

tel jetson wrote:I've got a 2004 Golf TDI that I run biodiesel in. the word I heard was that the 2003-2005 TDI had the right hoses/gaskets/seals for biodiesel standard, but newer models do not. I haven't bothered to look into that much further, but fuel system material compatibility may be an issue for you.



Most vehicles post 1994 have no material compatibility issues with biodiesel. We have a number of customers tooling around in 2013 VW TDI's with no fuel line issues.
4 years ago

Andrew Schreiber wrote:1.) I have concerns about how economical it would actually be run a biodiesal plant. Can you elaborate on the cost of set up, and the potential Return on that investment over the life of the system? Wondering primarily if the embedded energy in the establishment and maintenance of the system itself is greater or less than what the system processes. Perhaps there is a optimal scale for production?

2.) I wonder your opinion about where biodiesel stands in relation to other fuel sources, such as woody biomass from a longterm forest systems. In terms of it's resiliency and long-term viability, how can a person. My concern is biodiesel, as a energy-system, is not a net producer of energy. Which means it is invariably propped up by fossil fuels, making it only a short term option for people who have basically free access to waste stream oil, or who have ample and fertile enough land to grow energy crops. So that, a person spending the time and money investing in biodiesel system is going to get only get short term (less than one life time) use out of it. When another type of energy system would be a much more viable option long-term, and so it makes more sense to put the investment in the long-haul resilient technologies.



Hi Andrew,

Running smaller scale commercial biodiesel plants has never been very cost effective. This is why many smaller scale plants have failed and why very few are still operating.

The old rule of thumb used to be that the capital costs (equipment but not including buildings and land) run about $US1 per gallon of annual output - a 1 million gallon a year plant would cost about US$1 million in capital to set up. Depending on technology choices - this rule is still about right. Larger producers are more vertically integrated from field to fuel and can operate at a loss in the fuel making side of the business to offset profits in the food oil and meal side.

Conversion cost varies on feedstock and process, but for smaller plants (< 3 million gallons per year) the margins are typically negative without the US government subsidy of $1 per gallon, which is not in play right now and may or may not be reenacted retroactively in November. For our plant - we would lose 30 cents per gallon without subsidy and make 70 cents per gallon with it. Kind of like playing Russian Roulette and hoping to get lucky.

I believe that biodiesel makes sense in only a couple of niches - home or small co-op scale using WVO (Waste Vegetable Oil) collected from local restaurants and farms who can use the fuel and meal from some of a soy or canola crop on their farm to fuel their equipment and feed their livestock. I'm aware of a number of examples of both these cases that are working well for those whose site specific situations are favorable.

As far as biodiesel's resiliency versus other fuel choices, I'll comment on just a couple of aspects of this huge topic.

I don't see biodiesel as resilient at all, in anything but the very short run (which still is relevant IMHO). If by resilient we mean able to withstand shocks to the status quo, supply chains for methanol and KOH reach across the planet. Disruption of supply lines would render making biodiesel impossible as soon as you run out of methanol, KOH, or electricity. That being said, it is easy for someone to today to collect oil, turn it into biodiesel, and reduce their dependency on fossil fuels and save some money. Not a bad value proposition for those who don't mid spending some of their time and money on getting set up to do this.

As far as woody biomass goes, it's not currently very easy to run a vehicle on it. and I don't believe that we'll ever see cellulosic ethanol be a big player in our liquid fuel mix. It seems much more likely that the electric car's day is finally arriving.
4 years ago

howie story wrote:It seems the best vehicles for conversion to boi-diesel are the ones made in the 1980 - 1990 's . The engines are simpler to convert, with none of the fancy electronics modules and sensors. Not to mention the much lower purchasing cost.
My preference is towards the VW diesels of this era. What are your experiences with conversion of older (pre 2000) vs newer diesel engines to bio diesel?



Hi Howie,

I wonder is you're asking about converting cars to run on SVO (Straight Vegetable Oil) rather than running on biodiesel (chemically converted fats and oils).

Running biodiesel requires no vehicle modifications for cars and trucks newer than about 1994 - older vehicles often have fuel lines, gaskets, and o-rings that are susceptible to breaking down with the use of biodiesel due to its solvent properties. There are now fuel lines and gasket materials that can stand up to biodiesel use. So Post 1994 vehicles are usually easier to run biodiesel in, as no changing of fuel lines is required.

Running SVO requires modifications to the vehicle to heat the oil prior to combustion in order to reduce its viscosity so that it atomizes properly upon injection and puts less demand on the fuel pump. These modifications often include a second tank for the SVO, a heat source for the oil, and valves and themostats to control temperature and flow. Most conversions I've seen are on older equipment, where the warranty has long expired and the engines a bit more forgiving of SVO use.

As I don't enjoy wrenching on my car, I find commercially available biodiesel the right fit for me and my 1987 Mercedes turbodiesel wagon, in which I changed the fuel lines to tygothane.
4 years ago

Nick Kitchener wrote:Discovering that the amount of methanol involved can be very significant left me feeling rather disappointed.

Am I wrong in my views on biodiesel? Has technology advanced? Is there a process where the other main ingredients can be readily manufactured on a homestead (like ethanol)?

Your comments would be very much appreciated



Hi Nick,

I share your concern.

Biodiesel is term used for the fuel use of methyl esters - a product of a reaction involving methanol, fats or oil, and a catalyst typically potassium or sodium hydroxide (KOH or NaOH). Methanol is typically made as a byproduct of natural gas - often a byproduct of the petroleum industry and comes from places like Iran, Qatar, Trinidad, Equatorial Guinea , and Russia. KOH and NaOH typicaly comes from China these days.

A typical biodiesel reaction uses 22% by volume of the fat or oil to be converted - not insignificant.

Ethyl esters (made using ethanol) are another possible fuel source but the processes required to produce anhydrous ethanol (without water) are a bit daunting for homescale. The alcohol (methanol or ethanol) needs to be about 99.5% pure or better to make the reaction worthwhile. The amount of ethanol required to make ethyl esters is also greater, which is partly why it's not cost competitive commercially.

To my knowledge, there is no energy without impact - not wind, solar, hydro and certainly not biofuels. The original biofuel that powered people and farms was hay for farm animals - also not without impact but arguably more sustainable that solar, wind, hydro, and biodiesel or ethanol. I think the more we can reduce our need to commute, shop, and recreate far away from our homes, the better our lives will become. Call me a Luddite!

Although I garden daily, home brewed beer for 10 years, and my wife has been making all of our bread for about 10 years - I have never homebrewed biodiesel. I have worked with five commercial biodiesel producers so have been able to run my vehicle on B100 for the last 14 years. I'll admit that if and when I don't have access to commercial biodiesel, I have no intention of homebrewing myself - just not into it. I'd happily buy it or trade for it with someone who did though!
4 years ago

Adam Geriak wrote:I am wondering if ANY diesel engine can be converted into Biodiesel? Even the very big machines? Does the cost of the transformation increase as size of the machine increases?



Hi Adam,

The short answer is "yes". Any diesel motor *can* run on biodiesel.

and as far as "transformation" - depending on the piece of equipment - "maybe".

Diesel motors made after about 1994 should have elastomeric ("rubber") components compatible with biodiesel so no conversion of the motor is required. This was due to the introduction of better fuel system materials introduced to support low sulfur diesel.

If your equipment is pre-1994, you'll need top replace fuel lines due to the strong solvent properties of biodiesel. And if there's other "rubber" components in your pre-1994 fuel system like gaskets and o-rings, they'll like start to leak over time as well.

That being said, poor quality fuel can clog filters and leave you by the side of the road (or missing your harvest window) at the worst possible time. Making good quality fuel is not difficult, but many people will cut corners and learn the lesson the hard way.

A good farmer friend of mine grows soy and canola on his farm and crushes some of the crop to make biodiesel and meal for his cows and turkeys. Although he has run his combine on his home made fuel, he prefers to use it in his lower risk farm equipment and remove the stress of introducing another variable into his harvesting operation. Biodiesel breaks down faster than diesel fuel which is great for the environment in case of a spill, but no so good in the tanks of equipment that doesn't get used every day - like combines, backup generators, and firetrucks.
4 years ago