Biodiesel and your vehicle
Spanish version -- Versión en español
Compatibility:
-- Filters
-- Timing
-- Rubber
Biodiesel quality
-- Homebrew quality
-- Homebrew vs commercial production
Why quality matters
Quality testing
-- Wash test
-- What should you do if your fuel doesn't pass the wash-test?
-- Reprocessing test
-- Methanol test
-- Methanol test by mass
-- Reprocessing biodiesel
-- How to use the quality tests
-- More quality checks
Standards for biodiesel
Using biodiesel in winter
Biodiesel in gasoline engines
Very Frequently Asked Question: "Can I use biodiesel in my car?"
Answer: If it's a diesel, yes. But there are a few things you need to know.
Filters
Conventional fossil-fuel petrodiesel is dirty stuff. Not only are the exhaust fumes dirty, but the fuel itself leaves a deposit in the tank and fuel system. Biodiesel isn't only clean, it's a good cleaner -- it does a great job of cleaning up the gunge the fossil diesel leaves. But then all the freed gunge blocks up the fuel filter.
When you first switch to biodiesel, check the fuel filters often and change them when needed. The first few weeks are the most important. Some people fit a second cheap filter upstream of the main filter for the first few weeks.
If a car has been left standing for a long time with petroleum diesel fuel in the tank, as with some second-hand cars up for sale, the bottom of the tank may have rusted (water content is a common problem with petro-diesel fuel). Biodiesel will free up the rust, and it could clog the particle filter inside the tank. At worst the car simply stops, starved of fuel. More likely the engine steadily loses power first, probably for long enough to get you there before it stops, the first time anyway. It's not a common problem, but it happens.
It's happened to a few older Mercedes in the US, and it happened to our 1990 Toyota TownAce, after running on 100% biodiesel for about a year. We took the particle filter out of the tank and replaced it with an external filter, which we cleaned very often, and after awhile it stayed clean. When we checked the tank the rust had gone. It had cost us an extra final filter element.
There's probably no need to take the precaution of removing the particle filter from the tank before there's a rust problem just in case it happens because it probably won't happen, and with some cars it's not easy to get the particle filter out of the tank.
Timing
Optional: Retard the injection timing by 2-3 degrees -- this overcomes the effect of biodiesel's higher cetane number. The engine loses a little of the extra power you get with biodiesel, but it runs quieter and the fuel burns cooler, reducing NOx emissions. (See also NOx emissions and biodiesel.)
Rubber
Rubber parts in the fuel system may corrode in time with biodiesel, especially 100% biodiesel (B100). Newer cars (since the mid-1990s) use resistant parts, and biodiesel is used in many older engines without any problems. If necessary, check with your vehicle's manufacturer. Viton parts are best. In fact these problems are rare -- just do it, go ahead and use biodiesel, and wait and see. If you do have problems it won't be soon and it won't be sudden, you'll have warning and it's easily fixed.
This is what commercial biodiesel producer Camillo Holecek of Biodiesel Raffinerie GmbH, Austria (http://www.energea.at/en_info.html) had to say about it:
"As a commercial producer I used to tell my clients: Any European car maker's product after 1996 is 100% biodiesel-proof, as countries like France are already mixing 5% biodiesel in their standard diesel fuel sold at the pump, and in the Czech Republic it is 30% in the 'Bio-Naphta' that is also sold to anyone at the pump, and none of those car makers wants to get a bad name that his brand car failed in those important markets.
"And by the way, Nissan Austria just approved its Primera for 100% biodiesel, too.
"We did hear of a few medium-aged trucks having the original injection pump seals going to pieces, after growing bigger over several months due to biodiesel 'attack'."
Terry de Winne (Biofuels for Sustainable Transport -- http://www.biofuels.fsnet.co.uk/) had this to add:
"Ultra low sulphur diesel fuel (ULSD) suffers from two things -- lack of the lubricity of the sulphur and also its ability to vulcanise any rubber components. Ergo, when Europe went over to ULSD in 1993/95, all fuel components were changed by all manufacturers to Viton or similar plastic.
"Initially, supplies of ULSD were found to be very harsh on the injectors and caused many problems. Most oil companies added lubricity additives to compensate.
"The French, being farmer-friendly, opted for biodiesel. The three main companies add 5% to all their ULSD. Shell International adds just 2%, but even this small amount is enough to compensate for the removal of the sulphur. It also oxygenates the fuel and brings the emission levels down marginally -- particularly carbon monoxide and nitrous oxide.
"Hence, all Euro vehicles are compatible with biodiesel, whether or not the manufacturers acknowledge it.
"Biodiesel, being an organic substance, tends to be absorbed by natural rubber -- after a month or so exposure, the rubber swells and rots. This applies to all ratios of biodiesel additive to petrodiesel. A tank or two to try it out will do no harm, if ULSD or standard diesel fuel is used thereafter.
"This is particularly applicable when using biodiesel in diesel generators, which are usually designed to run on high sulphur fuel, so probably have rubber hoses."
In fact it seldom happens. Any vehicle made from the early 1980s on is unlikely to have problems, even using 100% biodiesel. Some 1980s Volkswagen models eventually suffer return-line leaks, but you'll have warning of it and it's easy to replace the damaged part. As for injector pump seals, we've yet to hear of it actually happening with any clear proof that biodiesel was the culprit. Petro-diesel is also tough on seals.
Two of many similar enquiries sent to the Biofuel mailing list:
"I own a Toyota Corolla 2.0D van (1993), I was told that diesel fuel pumps in older diesel vehicles aren't compatible with the use of biodiesel. The rubber parts inside the fuel pump will be damaged and they aren't replaceable. A fuel pump is a very expensive part (hundreds of euros). Can anyone tell me if that's true?"
And:
"I've spent weeks since my first batch of corn-based BD came out of the processor trying to determine what will need to be done to my Datsun pickup before I get to use B-100 in it. It's a 1981, and although it's running alright on B-20, I have gotten the lengths of fuel line I'll need to replace to run on 100% biodiesel.
"It's my only vehicle, so I will have difficulty removing the seals for comparison at the auto parts store, unless I disassemble it in their parking lot.
"Has anyone else out there done a conversion on the same engine (vintage) as I'm dealing with? What parts are needed to complete? Do I just need a new pump? Are there rubber impeller seals inside it?"
Reply:
"If your biodiesel is properly made (i.e. a complete reaction) and, more importantly well washed (typically three or four washes), I see no reason to fear pump failure even in early pumps. The car companies say otherwise to cover their backs, and likewise the oil companies want you to keep buying their diesel. Having the pump rebuilt with a Viton kit is not necessary." -- Malcolm Maclure, June 2005
Petroleum diesel, even when it's not low-sulphur diesel, is aggressive stuff itself, it also attacks rubber and plastic. We have some tough 12-litre plastic carboys which we've been using for years for biodiesel, methanol, methoxide, glycerine by-product, by-product separated with concentrated phosphoric acid, and never had any problems until we stored some petro-diesel in one of them. After a while it just broke, the whole side fell out. Fuel-system parts are made to be resistant, but seals can wear out eventually anyway.
Biodiesel quality
Homebrew quality
Biodiesel made from different kinds of oil can have slightly different characteristics (see Oils and esters characteristics) -- some are better for cold climates, for instance. But it's all excellent fuel, even when made from used cooking oil (WVO) -- as long as it's well made. You CAN make high-quality biodiesel yourself if you follow the instructions given on this site.
Our normal production biodiesel made here at Handmade Projects from used cooking oil was tested by Gas Chromatograph at a technical university in Tokyo. "Very clean biodiesel!" was the comment on the lab test results. Ester content was 99.09%, a very complete reaction, better than the European EN 14214 biodiesel quality standard specification of 96.5% minimum ester content.
The lab staff said later it was the cleanest biodiesel they'd seen. "How do you make such good biodiesel from WVO?" they asked. See:
http://snipurl.com/pie8
[Biofuel] Biodiesel test results
11 Apr 2006
Aleks Kac, making homebrew biodiesel with his "Foolproof" acid-base two-stage process, has passed the German DIN 51606 tests twice, as well as the Austrian ONORM test, with samples taken from his normal production without any special preparation. Again, the lab was surprised he could make such good biodiesel from WVO.
- Make your own biodiesel
- Mike Pelly's biodiesel recipe
- Aleks Kac's two-stage process
- Aleks Kac's FOOLPROOF biodiesel method
"Backyard" and small-scale producers take a pride in what they do, many or most of them make high-quality biodiesel. Jack Kenworthy, a teacher at the Cape Eleuthera Island School in the Bahamas, joined our Biofuel mailing list in November 2002 as a novice. List members helped him learn how to make biodiesel from scratch, helped him solve problems he encountered, then helped him design and build a processor. Nine months after joining he wrote to the list:
"Hey All -- just thought I would let you know that I just received my results from the ASTM tests [the US ASTM D-6751 biodiesel standard] and we passed all categories. Just another good example of a homebrewer in a remote setting (Bahamas) making spec-grade biofuel! Thanks! -- Jack"
Jack uses the single-stage base process and makes the fuel in 150-gallon batches, totalling about 300 gallons a week. He uses waste vegetable oil from cruise liners that call at the island once a week.
See: Standards and the homebrewer -- "Most of the ASTM D-6751 standards can be met simply by preparing and washing the fuel well," says Todd Swearingen of Appal Energy.
We've received many reports from people using their own fuel of how diesel engineers were surprised at how clean their engines are following a professional inspection.
Homebrew vs commercial production
You can make better fuel yourself than the big commercial companies often do, despite the industry mythology to the contrary.
On 7 Nov 2002 Graham Noyes of World Energy, a major commercial supplier of biodiesel in the US and beyond, wrote to the Biofuels-biz mailing list:
"The big fear of the biodiesel industry is that homebrewers are going to destroy the market. I have seen home-brewed biodiesel cause problems in multiple locations and it has taken significant efforts to undo the damage. One region of the country in particular had large quantities of homegrown off-spec fuel that was being sold and distributed. The use of biodiesel was substantially delayed in this area until trust for the fuel was re-established."
But, though put under considerable pressure by list members, he was unable to provide any details of this catastrophe. Three weeks later he changed his tune:
"After some experience here, I have a much better understanding of the efforts that are being made to make top-quality fuel. I also think I should provide some more details regarding my perspective on homebrew (and should have been more careful about sweeping statements in the first place). While I do nothing but biodiesel 40-70 hours/week, I have not seen any significant problems result from the use of homebrew. There are concerns but these are primarily perception rather than experience."
An apocryphal tale, as we'd charged: there was no off-spec homegrown fuel causing problems, it was just industry rumour-mongering. But Graham earned the homebrewers' respect for admitting it -- and now he works to counter such negative mythology in the industry in the US, and heads a committee focusing on small-scale producers at the National Biodiesel Board (NBB, which represents the commercial industry in the US).
Some months later, in May 2003, World Energy recalled a consignment of commercial biodiesel from the Pacific Northwest because it was sub-standard, with a "high glycerine content" (ie unwashed fuel). To their credit, World Energy acted quickly to withdraw the fuel, replace it with quality fuel and repair the PR damage. But soon afterwards several thousand gallons of commercial biodiesel distributed in the San Francisco area (not by World Energy) turned out to be very poor-quality, sub-standard fuel (also unwashed, and worse) and was recalled, fortunately before it reached consumers.
In summer and fall 2003 there were serious problems in California with bad-quality biodiesel produced by NBB member Imperial Western Products' plant, which cost drivers repair bills. IWP went on delivering the bad fuel, it wasn't just a single bad batch. The fuel was independently tested twice and found to contain high levels of triglycerides -- there was unconverted oil in the biodiesel. The NBB was not aware of the issue, and in fact scheduled a tour of the Imperial Western Products plant on the NBB convention agenda after the incident.
The NBB continues to attack homebrewers: "'Unlike commercial biodiesel, the homemade fuel is not held to ASTM International specifications drafted to protect engines,' said Jenna Higgins, spokesman for the National Biodiesel Board. ... Fuels from home reactors would void engine warranties, she added." -- From Grease-guzzlers thrive on leftovers, Arkansas Democrat-Gazette, February 26, 2006
http://www.nwanews.com/adg/News/146919/
There is similar industry prejudice in other countries, and it's similarly baseless.
Aleks Kac reported this:
"For nosyness' sake I tried the ole' quality test (mix a little water in your finished product and watch the separation -- see below) but with a commercial biodiesel sample from Austria. Horrifying results: it created a thick white foam between the water and bio layers. The white foam thinned to 1/4 of the thickness in two weeks, but hasn't disappeared. After two weeks the fuel still hasn't cleared. Conclusion: this commercial biodiesel is not washed with water! I suspect it has merely the methanol distilled out and been neutralized in a solid acid bed."
Rob Del Bueno of Vegenergy resells commercially manufactured biodiesel. He told the Biofuel mailing list:
"Over the past two years I have seen the quality of this fuel vary greatly. Funny thing about the 'commercially manufactured' biodiesel... One of the big arguments against backyard biodiesel (from industry folks) is quality, yet every batch that I have made, and every batch I have seen by a homebrew biodiesel maker has been much better than the 'fuel' I am reselling. Individuals with small-scale setups seem to really care, take their time, and craft their fuel... after all, most are using it in their own cars, not selling to the boiler fuel market."
You can do it too.
Why quality matters
A message to one of the biodiesel discussion groups told how someone had made some biodiesel by shaking the ingredients up a few times in a plastic bottle and put it straight into his tank: "... I've had dozens of trouble-free miles!" he enthused.
Unlike gasoline engines, diesels will run on bad fuel -- for a while: they'll run on used motor oil, or with kerosene or even gasoline added, or on sub-standard, unwashed biodiesel. But diesel motors and their fuel systems should last 250,000 miles or more, half a million miles is common. Dozens of miles, 10,000 miles or even 20,000 miles don't mean much. A real test would be over at least 250,000 miles on unwashed biodiesel with all its contaminants -- soaps, excess methanol, residual lye, free glycerine, with regular engine disassembly and full professional examination for wear. There aren't any such scientific tests, especially as standards committees and other professional bodies in several countries have already determined what damage these contaminants and impurities do -- that is the basis of the various national standards for biodiesel.
Here's what the Fuel Injection Equipment (FIE) Manufacturers (Delphi, Stanadyne, Denso, Bosch) have to say about biodiesel quality:
Summary -- html
Full document -- Acrobat file, 104kb
Quality testing
Wash test
This is the most useful all-round test, and it's very simple: Put 150 ml of unwashed biodiesel (settled for 12 hours or more, with the glycerine layer removed) in a half-litre glass jar or PET bottle. Add 150 ml of water, screw the lid on tight and shake it up and down violently for 10 seconds or more. Then let it settle. The biodiesel should separate from the water in half an hour or less, with amber biodiesel on top and milky water below. This is quality fuel, a completed product with minimal contaminants. Wash it, dry it and use it with confidence.
But if it turns into something that looks like mayonaisse and won't separate, or if it only separates very slowly, with a creamy white layer sandwiched between water and biodiesel, it's not quality fuel and your process needs improvement. Either you've used too much catalyst and made excess soap (better titration), or a poor conversion has left you with half-processed mono- and diglycerides, fuel contaminants that act as emulsifiers (better titration, try more methanol, better agitation, longer processing time, better temperature control), or it's both too much catalyst and poor conversion. See Emulsions.
Whichever, you're headed for washing problems. Super-gentle washing techniques might avoid the problems, but you'll still be left with poor-quality fuel laced with contaminants that can cause injector coking and engine damage and they can't be washed out.
If you have an emulsion any thicker than the normal "paper thin" interface layer between oil and water, the batch should probably be retreated. See Reprocessing biodiesel, below.
Bubble-washing is also gentle, and it's worth repeating the test with some washed fuel after bubble-washing -- it should separate from the water cleanly within a few minutes.
Also try the Methanol test, see below.
See:
Washing
How the process works
How to use the quality tests
What should you do if your fuel doesn't pass the wash-test?
See Accurate measurements
Frequently Asked Question: "Alright, I'm stumped. When I tried to wash the biodiesel with tap water, it formed a white emulsion. I've waited a long time but there was no separation, absolutely nothing. What happened?? What am I doing wrong??? Can I make biodiesel with this oil?"
Answer: Keep trying, make more test batches, practice makes perfect.
Learners at the Biofuel mailing list:
- Re: Alright, I'm stumped -- Sad to say but I think most of us have screwed up at one point or another. My big mistake was the very first thing doing the titration with the Better Titration method, but I forgot one minor thing. So from that point all was up hill. I was checking my process one thing at a time, checking and rechecking, but all I did seemed to be A1. After thinking that this was all a trick, I found the first thing I did was wrong. Now all is well with the process. Until I mess up once more. -- Derick Giorchino, 10 Oct 2005
- Re: Alright, I'm stumped -- Sounds like my first run and I'm no expert now but ... I had to eliminate the variables one by one. So I got virgin oil, got better at titration, got better lye (and how to measure it!) -- and Bingo, there it was, perfect biodiesel. Make sure you measure your lye very carefully, I found I added too much the first time and smoked a blender. But it was this and several other blunders that have made it easier to get along with now. -- Jim, 10 Oct 2005
Perseverance furthers.
"I went from 1 & 2 liter test batches to a small 15 liter processor and all went fine. When I bumped up to a 30 gal batch I got incomplete reactions and the emulsions during wash that can go with it. The washed and dried biodiesel looked great, but produced more glycerine when a sample was reprocessed. Following advice from Keith Addison at Journey to Forever I scaled down the volume of the batches, increased the temperature a few degrees, and increased processing time... It takes less time and it's less expensive to process it right the first time than to have to reprocess a batch. -- Tom Kelly, Biofuel mailing list.
Now Tom uses stir-washing and doesn't get emulsions.
"It is my belief (may be wrong) that the higher the quality of biodiesel the more rigorous the wash agitation can be. The batches that I have made that cannot take stir washing (emulsions occurred) have invariably been the result of incomplete reactions. As the biodiesel I make has increased in quality, it has stir washed very easily.
"For anyone starting out or still in the R&D phase of scaling up and tweaking the process to improve quality, disregard anything other than the tried and tested directions at Journey to Forever. Read them and then re-read them. Follow the instructions, don't add or subtract anything and you will be making quality biodiesel." -- Tom Kelly, 5 Nov 2005
See also How to use the quality tests, below.
Reprocessing test
Todd Swearingen of Appal Energy in the US offers some useful D-I-Y quality tests:
"The barnyard tests for your fuel are to take a liter of finished fuel, process it again as if it were new veg oil. If any more glycerine drops out, then you know it wasn't as good as it could have been.
"Also, look at your wash water. The second wash should be almost completely clear. The third wash should be nearly crystal clear.
"After settling 24 hours after a third wash, the fuel should be transparent when held up to light in a glass jar. If slightly hazy, simply heating the fuel to 90 deg Fahrenheit (32 deg C) should clarify it.
"If it clarifies with minimal application of heat, throw it into your tank and go see your mum for the weekend.
"If all of the above 'tests' turn out well, you probably have a fuel that would analytically beat fuel produced using continuous process (i.e. commercial) methods."
Methanol test
Jan Warnqvist uses this test:
"Take exactly 25 ml of biodiesel and dissolve it in exactly 225 ml of methanol in a measuring glass.
"The biodiesel should be fully soluble in the methanol, forming a clear bright phase. If not, there is pollution in the biodiesel. Each ml of undissolved material corresponds to 4% by volume. Is there any undissolved material at the bottom of the measuring glass? If there is, your reaction is not complete and this is causing you trouble with the water test.
"This method does not cover every aspect of quality, but it gives a hint. It is valid only for biodiesel made from vegetable and animal oils. It is not valid for biodiesel made from oils with a very wide fatty acid pattern, such as fish oils."
Jan Warnqvist
AGERATEC AB
Methanol test by mass
Determination by mass will give you a more precise result, says Jan Warnqvist:
Equipment needed for the analysis:
1. One 250 ml separation funnel
2. One 400 ml beaker
3. One magnetic stirrer
4. Balance accurate to 0.05 g
5. One 50 ml E-flask with narrowed neck
Chemicals for the analysis:
1. Water-free methanol, minimum 225 g
2. FAME (Fatty Acid Methyl Esters, biodiesel) with water content less than 500 ppm, clear, bright and without visible impurities, minimum 25 g
Take the clean beaker and put exactly 225 g of methanol in it. Then add exactly 25 g of the biodiesel.
Stir the fluids with the stirrer for 2 minutes.
Take the beaker off the stirrer and pour the contents into the separation funnel.
Set the clean e-flask on the balance and set the balance to zero.
Let any oil phase separate out from the biodiesel/methanol phase and put it in the e-flask.
Weigh the contents and calculate the result as follows:
1 - m1/m2 = m3
where
m1 = the amount of undissolved material
m2 = the amount of biodiesel put into the reaction
m3 = the amount of biodiesel that is dissolved in methanol in mass %
Example:
m1 = 0.5 g undissolved material
m2 = 25 g biodiesel put into the reaction
1 - m1/m2 = m3
1 - 0.5/25 = 0.98
m3 = 98% of the biodiesel dissolved in the methanol, leaving 2% unreacted oil.
Ideally there should be no undissolved material, indicating a high conversion rate leaving no unreacted oil and only small amounts of diglyceride and monoglyceride.
Reprocessing biodiesel
For failed batches, reprocess as with fresh oil, with the standard 3.5 g of lye per litre of oil but using only 100 ml methanol per litre of oil.
Message to the Biofuel mailing list, 22 September 2005:
I tested some biodiesel after processing it by treating it as new virgin oil and some additional glycerine dropped out. Do I use 10% methanol and 3.5 g NaOH/liter per Journey to Forever to reprocess the batch? Won't that cause washing problems because of the additional NaOH causing an emulsification? -- Todd H.
Reply:
I reprocessed a 95-litre batch using 10% methanol and 3.5 g NaOH per liter as per Journey to Forever. I recall having the same question you pose re: the lye. I simply followed the instructions given at Journey to Forever and slightly more than a gallon of additional glycerine mix separated out. The reprocessed biodiesel washed beautifully without emulsion and after three washings and a few days drying in the sun was crystal clear and ready to use. -- Tom K.
How to use the quality tests
From Tom Kelly, Biofuel mailing list, 9 May 2007:
It is my impression that a thicker than "paper-thin" middle layer in the Wash test may not indicate an incomplete reaction, but rather excess soap production. This may be due to high FFA content in the WVO oil, water in the oil, water in the caustic [lye catalyst], or in the methanol. It may even be due to too much caustic.
For these reasons, and others, beginners should start with small (1-liter) test batches using virgin oil, the highest quality chemicals, and balances that allow accurate measurements.
Much of the soap settles out with the glycerin, as does most of the caustic and excess methanol. Even after 12 or 24 hours of settling some of the soap, caustic and excess methanol is still in the biodiesel fraction. That's why we wash it. The amount that remains is related to the amount produced in the reaction.
Using virgin oil eliminates not only the need to titrate, but also soap formed due to FFAs in the oil. Initial test batches with anything other than the "paper-thin" middle layer (wash test) are unacceptable because it indicates either an incomplete reaction or excess soap. Given virgin oil, accurate measurements, and quality chemicals excess soap should not form.
After success with small (1-liter) test batches using virgin oil, one may begin using WVO and eventually scale up to larger batches. This not only increases the volume of a potential disaster (Emulsions), but also increases the number of variables that must be considered when a problem arises.
How do you know what is causing the problem?
Become familiar with the Methanol test described at Journey to Forever (see above).
If there was an incomplete reaction and various glycerides remain in the "biodiesel", they will remain undissolved in the methanol and form a residue at the bottom; reprocessing is in order (above). If the entire sample of biodiesel dissolves in the methanol, but the wash test resulted in a thicker than "paper-thin" middle layer, the problem is soap formation. If using virgin oil (or low-titrating WVO) and too much soap forms, consider the possibility of water contamination or inaccurate measurements/calculations.
Example: During methanol recovery (from glycerin mix) one must consider water contamination in the distillate. Using the recovered methanol may result in a complete reaction with little soap (good methanol), complete reaction with more soap than expected (some water contamination), or incomplete reaction with a lot of soap (serious water contamination).
The more serious problems are invariably associated with the last liters of methanol that were distilled. I have had a similar experience using the last gallons of methanol from a barrel. As the barrel empties, water in the air condenses, with more water in the final gallons.
The wash test and the methanol quality tests are both valuable.
Towards the end of each reaction, I shut off the pump and draw off a sample of the mix, and then turn the pump back on. I let the mix settle for about 10 minutes and then do a solubility-in-methanol test (Methanol test) on some of the biodiesel fraction. If it passes, I pump the mix into my settling tank. If I'm making fuel for my car, and the biodiesel fails the test, I'd add a bit more methoxide and continue processing. If I'm making fuel for my oil-fired boiler (larger batches; only 16% methanol vol/vol) a small residue of unreacted oil is acceptable. Testing this way saves the expense of time and resources involved in reprocessing.
Prior to washing a batch I always do a wash test. If the batch passed the methanol test, but there is a thicker than "paper-thin" middle layer I may let it settle longer, or put a few extra ml. of phosphoric acid in the first wash water.
Having passed the methanol test, I wouldn't consider reprocessing.
-- Tom
More quality checks
Aleks Kac has provided some useful quality checks you can do yourself:
- Nicely cracked biodiesel: very pale yellow (less than virgin sunflower oil) and no change in color with artificial lighting;
- Acceptable biodiesel: yellow like virgin sunflower oil or straw, but will get orangey undertone in reflected tungsten light;
- Deeper color biodiesel has a lot of glycerine in it in the form of various glycerids. Not good for standard engines. Remedy: If the diesel is too dark and you are sure that you used the correct quantitie(s) of catalyst(s), add a pinch more alcohol -- you could be losing it due to evaporation."
"Diesel engines require fuel of a certain quality. You just can't pour poor-quality biodiesel into the tank and expect the engine to go on and on without problems. You have three very dangerous enemies: free glycerine, poorly converted oils/fats and lye catalyst. Free glycerine and mono-, di- and triglycerides (poor ester conversion) will form gum-like deposits around injector tips and valve heads, lye can damage the injector pump. The key to good fuel is to just do it right and finish it! Use pure chemicals (sulfuric acid, lye and methanol) and measure them accurately. A proper wash will get rid of any glycerine and remaining lye.
"There is a rule of thumb: the brighter yellow in color, the better the crack. As a standard you should take virgin sunflower oil yellow color in see-through sunlight. (It's a sort of colorometry). Then take a glass jar of your fuel and place it in front of a white wall in the evening. When seen in the reflected light of a tungsten bulb it should not change to orange (a very simple case of absorbtion spectrometry).
The USDA's Agricultural Research Service has adapted a sophisticated tool known as Near Infrared spectroscopy, or NIR, for testing the quality of biodiesel.The standard method is the gas chromatograph, a complex piece of equipment that needs technical expertise, takes time, and requires special chemicals. NIR can also be used for determining fatty acid composition in vegetable oils and oil content in seeds, and needs no special training. It uses light rather than chemicals to perform the analysis, and can measure the conversion of vegetable oil to biodiesel in less than a minute.
Standards for biodiesel
Oils and esters and characteristics
Iodine Values
Quality standard for rapeseed oil fuel
Cetane Numbers
National standards for biodiesel
Fuel properties of fats and oils
Fuel properties of esters
US standard -- D6751-02 Standard Specification for Biodiesel Fuel (B100) Blend Stock for Distillate Fuels. Download from the ASTM site, costs $30 (pdf):
http://www.astm.org/cgi-bin/SoftCart.exe/STORE/
filtrexx40.cgi?U+mystore+mofc8213+-L+D6751+/usr6/
htdocs/astm.org/DATABASE.CART/PAGES/D6751.htm
Or: http://snipurl.com/fva4
EU standard -- DIN EN 14214, Publication date:2003-11 Automotive fuels - Fatty acid methyl esters (FAME) for diesel engines - Requirements and test methods. Order from Beuth Verlag GmbH ("search" for "EN 14214")
http://www.beuth.de/index_en.php
Standard testing:
Biodiesel fuel testing for the US ASTM D-6751 standard:
Analytical Testing Services, Inc.
http://wetestit.com/
Harris Testing Laboratories, Inc.
http://www.harristestinglab.com/quote/d6751.htm
Using biodiesel in winter
Like petroleum diesel fuel, biodiesel clouds when the weather gets cold, filling with little crystals of wax that can clog the fuel filter. When it gets colder still the biodiesel gels -- sets solid and won't flow or pour. But petroleum diesel fuel, especially winterized or #1 diesel fuel, can take more cold than biodiesel can.
Here's what you can do about using biodiesel in cold weather:
Biodiesel in winter
Biodiesel in gasoline engines
Biodiesel can also be used in gasoline (spark-ignition) engines, both 2-stroke and 4-stroke, but only as an additive. Users have reported good results with it, but it's still experimental, there are no guarantees.
See Biodiesel in gasoline engines
Biofuels
En español -- Biocombustibles, biodiesel
Biofuels Library
Biofuels supplies and suppliers
Biodiesel
Make your own biodiesel
Mike Pelly's recipe
Two-stage biodiesel process
FOOLPROOF biodiesel process
Biodiesel processors
Biodiesel in Hong Kong
Nitrogen Oxide emissions
Glycerine
Biodiesel resources on the Web
Do diesels have a future?
Vegetable oil yields and characteristics
Washing
Biodiesel and your vehicle
Food or fuel?
Straight vegetable oil as diesel fuel
Ethanol
Ethanol resources on the Web
Is ethanol energy-efficient?
