Introduction: Making Biodiesel From Waste Vegetable Oil

Maybe if Walt and Jesse had taken to making biodiesel rather than methamphetamine they would have had less trouble with the Mexican cartels, less murders and violence and an altogether easier life? Also a lot more environmentally friendly! There have however been some moments of excitement in my biodiesel career - on one occasion I was raided and interrogated by the Feds on suspicion of processing 'red' diesel into 'white', but fortunately they went away happy that I was innocent.

When I watched Breaking Bad there were quite a few actual similarities like, for example, always being wanting to perfect the product and taking a great pride in it. Some of the machinery in their industrial production plant looked a bit weird and unfortunately there was not enough pipework for it to actually work. It does however give some insight into what it is like to work with chemicals and in many ways making diesel (biodiesel) is a mysterious business and more akin to alchemy than science.

Biodiesel made from waste vegetable oil is possibly one of the most environmentally friendly fuels available for road vehicles. Yes, the methanol used is derived from petroleum but once it is reclaimed from the glycerol bi-product it's use is only at 14% by volume. It's not 100% carbon neutral, but goes a long way to help prevent climate change. A big bonus is that it is made from a waste product, which gives it a lot of extra points on the eco-friendly scale. Using new vegetable oil sometimes can have some negative consequences such as the destruction of natural environments by planting palm oil trees or competition with local food crops in countries such as Mexico, pushing up food prices. Please check the source when processing new vegetable oil!

Essentially, biodiesel is vegetable oil that has been broken down with chemicals to reduce it's viscosity thus making it spray out of a diesel injector nozzle with finer particles, making it easier and cleaner to combust. The main reaction takes place with methanol, which is a type of alcohol, in the presence of a strong hydroxide catalyst such as sodium hydroxide. Although the reaction itself is fairly simple, there are many steps in the process that involve heating, mixing, neutralisation, washing, drying and filtration. Waste oil presents it's own challenges - it's more tricky to process than new oil, but with good techniques devised over a ten year period we have 'cracked' it!

This instructable is a video based step by step of a training course but can not be thought of as a substitute for proper hands on training. Please do not attempt to make biodiesel without such training.

Difficulty:..........Training required
Cost:..........Starts at £2500
Satisfaction:..........
Hazards:..........See next step

Step 1: Health and Safety

There are considerable health and safety implications when making biodiesel. Some of the chemicals are extremely hazardous, explosive and inflammable. Never make biodiesel in your house or even in the garage unless it is separated from the house by at least 30 metres. If something goes wrong in your garage you may have a small fire which escalates to a large fire as other things in the garage start to burn and if your garage is connected to your house it could well burn your house down and harm those within it. Here's a run down of the individual hazards:

  • Methanol is flammable, burns with an invisible flame, it's vapor is explosive and it has a cumulative poisoning effect on the central nervous system.
  • Sodium hydroxide is caustic and will dissolve flesh when mixed with water. Wear gloves and goggles at all times when handling.
  • Sulphuric acid is extremely corrosive and will dissolve flesh and metal. It will also cause an explosion if water is added to it's concentrated form. Always add acid to water, never the other way round. Never use containers greater than 2 litres as they are too difficult to decant. Always wash jugs and measuring cylinders in water immediately after use as it's easy to forget.
  • Sodium methoxide is the chemical formed when sodium hydroxide is added to methanol. It has all the characteristics of methanol and sodium hydroxide so gloves and goggles are essential.
  • Vegetable oil is a slip hazard on the floor. Use sawdust to keep the floor slip free. Waste vegetable may be a bio-hazard if vermin such as rats have been near it. Rats carry many serious diseases which may be transmitted by their urine.
  • Chemicals need to be stored in locked cabinets according to local laws. Sulphuric acid must be stored separately from sodium hydroxide.
  • No smoking signs, no mobile phones signs etc need to be in place.
  • Fire extinguishers and eye wash kits are required.
  • Ensure that there is good ventilation in the building. Low roofed buildings are not suitable.

Step 2: Legal

The main legal implications are listed below but will be dependant on which country/state you live in so check your local laws.

  • Storage of methanol - consult your local fire department
  • Other fire regulations when processing oil and methanol - as above.
  • Employment of personnel - consult your local health and safety unit regarding using hazardous substances.
  • Tax - consult your local government tax office for taxes payable.
  • Delivery of chemicals - sometimes chemicals may not be transported in your own vehicle or delivered to a residential address.
  • Other laws particular to your country/state.
  • Environment protection authority

Step 3: Equipment and Chemicals Required

Equipment:

  • Biodiesel processor eg. TT700A. For safe operation the mixer tank should be separate from the heating tank and the heating tank must have level switch cut outs and thermostats installed.
  • Methoxide mixer
  • IBC's x 10 of
  • 14 cfm compressor
  • Electricity supply
  • Water supply
  • Drain to the sewerage system
  • Titration kit (see next step)
  • Large funnel
  • 10kg weighing machine
  • Personal health and safety equipment (goggles, gloves masks etc.)
  • Fire extinguishers
  • Eye wash kit
  • Sawdust for spillages
  • Pipe work
  • 100 ml plastic measuring cylinder
  • 500 ml ml plastic measuring cylinder
  • 1 litre plastic measuring jugs x 3
  • Mason / kilner jars x 5 of
  • Kettle for heating oil
  • Work bench for testing oils and samples
  • Plate and frame filter machine
  • Methanol storage facility
  • Chemical storage cabinets
  • Extraction fan and hood over the heating tank

Chemicals:

  • 2 litre bottles of concentrated sulphuric acid x1
  • Industrial grade methanol 200 litres
  • Industrial grade sodium hydroxide 25 kg
  • Waste vegetable oil 1000 litres

Step 4: Titrating the Vegetable Oil

Waste vegetable oil is commonly used for producing biodiesel and becomes degraded during the cooking process into it's constituent fatty acids. This can also happen with new oil if the raw seeds have not been stored properly. The acidity can not be measured with a pH meter or litmus paper as it is not an aqueous solution and so the titration method must be used.

Equipment required:

Instructions:

Add 1ml of oil to the flask and then 10ml of Isopropanol using the syringes and then 3 drops of the indicator solution. Whilst stirring the solution add the sodium hydroxide one drop at a time using the pipette until the indicator solution changes from yellow to green. Keep adding the drops until the green colour is maintained for at least 15 seconds. The amount of hydroxide used will be the final reading minus the initial reading, in ml.

If your amount of hydroxide used = x (ml) and the quantity of oil to process is y (litres), then the amount of solid sodium hydroxide required should be:

z = (x + 3.5) * y grams per litre.

For example, if the titration reading was 3.0 ml, then z will be 6.5 grams of sodium hydroxide per litre of oil.

Step 5: Mixing the Methoxide

We are planning to make a 700 litre batch and so need to make a quick calculation to get the quantities of sodium hydroxide and methanol. From the previous step we arrived at z = 6.5g grams per litre. Now the amount of sodium hydroxide will be z x 700:

s = 6.5 x 700 = 4550 grams = 4.5 kg of sodium hydroxide

The methanol required is normally 20% by volume of the oil although, with experience, this can be reduced slightly to save cost. Here is the methanol calculation:

m = 700 x 0.2 = 140 litres of methanol

So we now add 140 litres of methanol to the methoxide mixer and then pour in 4.5 kg of sodium hydroxide and stir for 5 to 10 minutes or until the granules can not be heard whizzing around inside.

Step 6: Making a Mini Batch

Equipment required:

  • 1 litre mason / kilner jars
  • 100 ml plastic measuring cylinder
  • 500 ml plastic measuring cylinder
  • Kettle
  • Stirring rod
  • Plastic 1 litre measuring jugs

The titration that we did in step 1 is a really good indication of how much chemicals to use to get a good biodiesel reaction, but it is not fool proof. Sometimes, with waste oil, there can be all kinds of weird contaminants that the titration test wont pick up on, so just to be on the safe side we test the oil once more by making a mini batch in a mason jar watching very carefully how quickly the black coloured glycerol separates out.

The process involves taking a 100ml sample from the methoxide mixer and a 500ml sample from the hot oil tank and mixing them together in a 1 litre mason jar. If the solution gets cold then it can be quickly heated in a kettle for about 5 seconds and poured back into the jar. If anything unusual is noticed in the next few minutes then the oil in the heating tank can be discarded before being pumped into the mixing tank, thus saving time and chemicals.

Step 7: Drain the Water / Gunge From the Heating Tank

The filling and heating of the vegetable oil is NOT shown in these instructions so we are starting from the point where the left hand tank, the heating tank, has about 750 litres of hot oil in it. After it reaches about 70 degrees C, the level in the tank needs to be brought down to 700 litres and the water and 'rubbish' that falls to the bottom of the cone is flushed out. This is particularly important when processing waste vegetable oil as there is often a certain amount of water etc. in the oil. It is of crucial importance that water is not accidentally pumped across to the mixing tank on the right hand side in the mixing / reaction stage as water will spoil the reaction and reduce the overall yield.

The level of fluid in the tanks is indicated by a sight tube running down the inner sides. This system is NOT fool proof as sometimes the tubes can become blocked or give false readings due to a difference in density of the fluid in the sight tube and the fluid in the tank itself. Believe me this happens, so watch out! The efficiency of the sight tubes can be improved by only opening the sight tube valve at the bottom when necessary, so preventing unwanted contamination entering the tube. A marker made by wrapping a cable tie around the tube is located at the 700 litre level point.

Step 8: Check for Contamination in the Mixer Tank

It's really easy to get water left over from the previous batch lurking in the bottom of the right hand mixer tank, so drain off any water by opening the bottom valve with a pipe connected to remove the residue. Never short cut this step as water will seriously affect the main biodiesel reaction.

Step 9: The Primary Biodiesel Reaction

The methoxide is now pumped out of the methoxide mixer into the right hand mixer tank with the sight tube valve remaining closed to prevent contamination. Then the hot oil is pumped onto the methoxide and simultaneously mixed. Never pump the hot oil in first as methanol can boil off the top of the oil if the oil is hotter than 64 degrees C. Another advantage of this technique is that the mixing is much more efficient than trying to mix a whole tank load of reactants and normally only needs 10 minutes of actual mixing time.

As the hot oil is pumped into the mixer tank, the temperature can be seen to slowly rise. If it gets to 64 degrees C then the pump needs to be switched off until the temperature has dropped down a few degrees, after which it can be turned on again. With practise it is possible to get the final temperature of the batch to exactly 64 degrees at the end of one continuous pumping procedure.

Now we take another sample of the contents of the mixer tank whilst it is still mixing to check that we are getting a good reaction. Very quickly we see glycerol separating out in our mason jar and can turn off the mixer system after 10 minutes of mixing the full tank load.

Step 10: The Secondary Biodiesel Reaction

The contents of the mixer tank are left to settle for exactly one hour and the crude glycerol is pumped out from the bottom of the cone until the golden biodiesel can be seen in the pipe work. At this stage the biodiesel is only about 80% pure and needs to be sent through another reaction phase to 'push' the reaction forwards.

The crude biodiesel is processed with 10% by volume of methanol and 1.4g of sodium hydroxide per litre of biodiesel. So for 700 litres of crude biodiesel the chemicals required are:

m = 0.1 x 700 = 70 litres of methanol

s = 1.4 x 700 = 1000 grams of sodium hydroxide

These ingredients are mixed in the methoxide mixer in exactly the same way as before but this time they are pumped INTO the mixer on top of the crude biodiesel. The reactants are now mixed for 10 seconds and allowed to settle for about ten minutes before draining off any glycerol that has settled to the bottom. Sometimes there is none at all!

An alternative method is not to perform the secondary reaction, but to allow the reactants from the primary reaction to stand for 3 days, during which time the reaction proceeds at a very slow rate as glycerol continues to settle out. (This method is not used so much these days).

Step 11: Acid Washing the Crude Biodiesel

In this stage dilute sulphuric acid is used to neutralise the residual sodium hydroxide in the mixer tank making it easier to wash the biodiesel in the next stage. If the catalyst is not neutralised it will tend to form soapy emulsions with some of the co-products when water is added. The amount of concentrated sulphuric acid required for 700 litres of crude biodiesel is calculated as follows:

a = 700 / 2.3 = 300 ml of concentrated suphuric acid

This is then carefully poured into a drum of 25 litres of water. Full personal protection equipment is required at this stage as the concentrated acid is extremely corrosive. Never try to use acid in large containers as they are too difficult to handle - a 2 litre container is the maximum.

The diluted acid is now slowly pumped through the spray nozzle in the mixer tank until the drum is empty. Much of the acid will fall straight to the bottom of the cone so it's a good idea to recycle it back through the spray nozzle to get more efficiency from the acid. This is done for about 5 minutes, watching carefully what the fluids look like as they exit the cone pipe work. If biodiesel starts to come through, the air operated diaphragm pump needs to be slowed down.

Step 12: Water Washing the Biodiesel

Water is now used to wash out all the residual chemicals and glycerol in the crude biodiesel. Great care needs to be taken to prevent emulsions of water with the diesel, particularly if the original feed stock had a high fatty acid (FFA) value in the titration stage.

The valve on the sight tube is now opened and water is sprayed in through the spray nozzle in the mixer tank using mains pressure - about 2 bar. The dirty water is simultaneously drained off from the bottom of the cone, taking care not to drain off too much and get into the biodiesel layer. In any case, the water is always drained into an IBC so as to catch any biodiesel that gets through by mistake. (IBC = intermediate bulk container).

Normally about 400 litres of water is required for a 700 litre batch, but this could be more if the vegetable oil was of high FFA. The trick is to keep looking at the colour and consistency of the waste water coming out. The flow of water going in is regulated using the ball lever at the top of the main in such a way that it balances the flow of waste water coming out. This is a bit of an art and is aided by looking at the sight tube, checking that the level is not too high or too low and checking the waste water coming out. The whole process normally takes about 1 hour.

Step 13: Draining Off Residual Water

Now the contents of the mixer are allowed to stand for about 60 minutes to allow any residual water to settle out to the bottom of the cone. The more time given to this stage of the drying process, the less time required in the heating tank so it is a bit of a balancing act here.

The residual water is now drained off and the wet biodiesel is pumped back over to the heating tank for the final drying stage. It's a really good idea to allow the wet biodiesel to flow by gravity as much as possible and only use the pump when the levels in the two tanks have equalised - this will prevent any droplets of water hanging about on the mixer tank walls from emulsifying in the diaphragm pump due to it's aggressive action. Once the mixer tank is empty, the heating tank elements can be turned on and left to heat to about 70 degrees C. At this temperature most of the dissolved water will separate out and fall to the bottom of the cone. However, there is still a very small amount of water dissolved in the biodiesel and this needs to be removed by spray drying. At this stage, residual water in the cone must be removed as otherwise it will be picked up by the circulating pump and ruin the effectiveness of the drying stage.

Step 14: Drying the Biodiesel

The hot biodiesel is now sprayed back on top of itself using the electric centrifugal pump at the bottom and spray nozzle in the top of the tank. An overhead hood type extractor fan removes any fumes from the work area. This part of the process normally takes about 15 minutes and the effectiveness of the drying can be observed by watching the temperature of the tank contents. If the temperature is falling it means that the biodiesel is still wet, if it starts to rise then it is dry. Now samples from the heating tank can be taken and the process is finished when the sample stays bright and clear at room temperature.

If the electric circulating pump is turned on and the flow seems to be restricted, there is probably a blockage in the brass filter unit located upstream of the pump. It has a gauze that protects the pump from damage and can be removed, cleaned and replaced.

Step 15: Filtering the Biodiesel

Finally, the biodiesel needs to be filtered before using in a vehicle. The best type of filter machines are the frame and plate type which have a very low running cost and massive capacity for removing particles. Cartridge filters can also be used but they will be expensive to use in the long run as they will block up fairly quickly. The cartridges themselves would need to be rigid enough to sustain high pressures and normal water cartridges are not suitable. ProBond filters are the ones to go for. The biodiesel is left to stand for about 3 days, by which time any wax that wants to form will appear as a wispy haze in the sample jar. If a diaphragm pump is used, this waxy biodiesel can be pumped through a frame and plate filter without breaking up the wax too much.

Now that you have a quantity of finished biodiesel you will need to blend it with diesel according to the ambient temperatures and your vehicle warranty. Some people just go ahead and use it 100% with no problems but there are definitely issues with vehicles with a DPF (diesel particulate filter) fitted. Biodiesel is not compatible with the DPF as it does not ignite in the unit as it is supposed to and the unit then becomes broken, at considerable expense to the owner. Even filtered biodiesel will go waxy at low temperatures, depending on the nature of the vegetable oil originally used. Typically, it will start to wax at about 5 degrees C so will need to be blended with diesel to prevent the vehicle fuel filter from becoming blocked.

Step 16: Play All the Videos in Order

If you've got 77 minutes to kill, you can watch the whole training session here in one go.

If you enjoyed this Instructable, please vote generously. Thank you.

PS. An oscilloscope would be really useful for my electronic projects.

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Comments

author
sbayley2 (author)2017-07-23

Hey, thanks for the instructable.

I wanted to know if you have ever tried to make biodiesel out of insect oils?

It's an avenue I would be interested in exploring.

thanks
Sheldon

author
QasimA12 (author)2016-03-30

very nice

author
bobthemoron (author)2015-07-21

Who has $3500 lying around to produce what may or may not run your vehicle? Seems silly to me. Wood gasification makes a lot more sense as there are far more gasoline driven vehicles, generators, etc.

author
vipin786 (author)2015-01-25

Whats the cost of production of bio diesel(assuming waste vegetable oil is free) when compared to regular diesel in your country, Can this bio-diesel be directly used in trucks and other vehicles which use regular diesel without any vehicle modification.

author
deba168 (author)2015-01-16

Very nice instructables.

I know people in our country used Jatrapha seeds to make Bio dissel.

author
Tecwyn Twmffat (author)deba1682015-01-18

That's very cool! Jatropha oil makes really good biodiesel and it's easy to grow the plant. The kernals of the seeds are however quite tough so a special oil extraction machine design is needed. I know there's a lot of this plant grown in Madagascar and India, but where else I wonder?

author
zazzbat made it! (author)2014-12-06

hey Tecwyn and to all,

here's just a simple instruction site for learning, and understanding; with a few seeds, Jack found a castle of plenty atop a cloud... http://www.wikihow.com/Make-Vegetable-Oil ...it's quite small scale, but for those who would like to know, here it is. Sunflowers are crazy insane in producing seeds, and you can literally crowd a small amount of acreage with them producing a nice crop. After sowing and reaping, following the instructions and voila! you have your pure clean oil for processing into biodiesel. well...enough to run a small engine for electricity, a converted Jeep...anyway, I would agree that the amount farmed for processing is dependent on the acreage farmed, and the processing system in place. 10 sq yd processed in a 10 x 10 ft shed maybe not much, but 10 sq mi processed in a plant operated in a warehouse sized building like Kraft Foods? Yep. Take care all...

sunflower-lightning-field-james-bo-insogna.jpg
author
Tecwyn Twmffat (author)zazzbat2015-01-18

I planted some sunflowers last spring and harvested about 5 kg of seed - it was really worthwhile!

author
Tecwyn Twmffat (author)2014-11-26

¿Alguien puede traducir esto en español por favor?

author
redsunmtm (author)Tecwyn Twmffat2014-12-01

buenas, traducir el que, todo el tutorial o solo tu comentario ?

author
Tecwyn Twmffat (author)redsunmtm2014-12-01

Sería realmente excelente para traducir todo el tutorial si eso es posible ? Sólo sé español con traductor Google !

author
redsunmtm (author)Tecwyn Twmffat2014-12-08

ok, por cuanto ? porque traducir 16 paginas no lo voy a hacer gratis tio... hubiera sido solo una igual te lo hago por nada, pero 16 !!! no tengo tiempo para regalar...

author
jf_blanco (author)Tecwyn Twmffat2014-12-03

Para los hispanohablantes el mejor videotutorial en mi opinión es este:

https://www.youtube.com/watch?v=Qj4eU9OFVuo

author
romanyacik (author)2014-12-05

We did this in chemistry class last month. We used potassium hydroxide as a catalyst instead of sodium though

author

That's very cool! Sometimes people do use potassium to make their biodiesel as, in the winter, the glycerol bi-product won't go to jelly so easily and won't block up the pipe work. The disadvantages of potassium is that it is mostly made into flakes and this is very dusty. The other is that more of it is required in the process and it is more expensive.

author
maxhuey (author)2014-12-01

Turn key operation here: https://www.youtube.com/watch?v=J7hndrw-w_4

author
Tecwyn Twmffat (author)maxhuey2014-12-03

Hmmmmmmnnnn ....... I like your avatar photo though, looks like a younger version of mine!

author
sekitori (author)2014-12-02

Nice !

It's actually illegal in NL to make your own fuel - something to do with evading taxes..

author
theturn (author)sekitori2014-12-03

I didn't know the EN was the same standard in The U.S., I would have thought an American standard would have been in place!. in reference the the guy from the Netherlands, the UK 'allows' home brewers to make up to 2,500 litres with no tax penalty per year. This came about when biodieselers tried to point out to the Government that their vehicles were far more carbon friendly than before and asked to be road tax exempt (a tax based on the CO2 emissions of each vehicle) The Government quickly thwarted this with the 'tax free' 2,500 litre limit. Both sides then shut up, because a) how were the government going to regulate home brewers production and b) The home brewers knew if they pushed, more sweeping laws would be passed to screw it up completely.

author
Tecwyn Twmffat (author)theturn2014-12-03

Well said Amigo!

author
Tecwyn Twmffat (author)sekitori2014-12-02

Thank you for your reply sekitori. I am intrigued, are you in one of these places: Netherlands, Newfoundland and Labrador, North Lanarkshire or Nuevo León ?

author
sekitori (author)Tecwyn Twmffat2014-12-02

Netherlands.....

author
Tecwyn Twmffat (author)sekitori2014-12-02

Cool. I'm sorry it's illegal in your country. Could you register to pay the taxes?

author
sekitori (author)Tecwyn Twmffat2014-12-02

Hi Tecwyn, thanks for your interest.

I'm pretty sure it COULD be done, but then you'd need all kinds of permits (e.g. to handle/store flammable liquids) which would make it virtually impossible or at the least very expensive for a person to do so.

These guys at the taxes department are very clever :-(

However, I heard of people adding a percentage of vegetable oil to their diesel after filling up at the gasstation. This is also illegal (of course.....) but who is going to check that ?

author
jf_blanco (author)2014-12-03

Para los hispanohablantes el mejor videotutorial en mi opinión es este:


Nice tutorial though :-)

author
Tecwyn Twmffat (author)jf_blanco2014-12-03

Gracias amigo. El video se ve muy interesante.

author
theturn (author)2014-12-02

Hi, great instructable. I've been making Biodiesel (BD) for about 4 years now, and have only produced one failed batch (the second one I ever made). For those thinking about starting up, its often a good idea to start smaller, say 100 litre batches. It cast me about £650 including plenty of chemicals, filters, and oil for a batch.

I've tinkered with my process over the last few years and can confidently say its the best it could be for home brew : Crystal clear (varying in shade of yellow batch to bathc - depends on stock), always passes 27/3 test & fairly confident it would be within EN 14214 (the Euro norm standard for FAME / fatty acid methyl esters or Biodiesel!). My current car (2.2 CTDi Honda CR-V) has done over 25,000 miles and returns around 43 mpg average on 100% BD all year round.

I've thought about making an instructable with my process (2 stage Base) but that was as far as I got.

I would question a couple of your timings in your process, if I've read them correctly the first being 10 mins mix followed by 10 secs second stage mix, Most processors call for a hour then an hour, since it is a diminishing reaction, unless your using some kind of super pump, but for a batch that large, 10 minutes and then 10 seconds cannot possibly allow such volumes to transesterify. Also 64 degree is dangerously close to the boiling point of methanol, is the process pressure sealed?. Typical process temperatures are 52 to 55 degrees C. I only ever need to wash with water (I use Potassium Hydroxide (KOH), which as I'm sure you know gives liquid glycerol and is very forgiving as a catalyst in the reaction) If you're producing crude BD that is difficult to wash, you may not be dealing with a complete reaction. The 27/3 test will quickly show you this. The more complete the reaction, the quicker and easier it is to wash.

You are right in that you can use slightly less than 20% methanol in the reaction, but since it is a reversible reaction, 20% is specified to ensure a push over. Using your glycerol from the previous batch to 'prewash' your oil is an excellent way to a) lower titration of your stock, b) recover any lost oil / BD / catalyst and added benefit of drying your oil. Water is the absolute enemy in oil.

Of course, you can't do this using NaOH, since it sets solid when cool, which is another reason to use KOH as a catalyst.

There has also been several in depth studies available online, as to suitability of BD in DPF vehicles, and on the whole it was found that the oxides of nitrogen present in BD exhaust was found to help the DPF regenerate at lower temperatures in mineral/BD mixes, requiring lower revs to enable the regeneration. However, and free glycerol in BD will ash up the DPF until it is ruined, is is essential that glycerol is removed. Glycerol can also gum up injectors, since it is not dissolved in any way by the BD (which is of course how we are able to remove it at the separation phase)

As I understand it (from studies and research and the lack of black clag shooting out of my exhaust) BD when burnt in a diesel engine does not produce the same soot associated with mineral diesel, which is why 100% BD engines do not regenerate the DPF.

Biodiesel is added to pump diesel (UK at least! 5-7%), since sulphur was removed to prevent injector pumps and injectors seizing, because sulphur was used as the lubricant and because biodiesel has excellent lubricating properties. I am lead to believe some European countries are now at 30% BD in the pump diesel. I haven't heard of any rumblings in the DPF are yet, but will keep a close eye on that one.

In any case, well done on the instructable.

All the best.

author
Tecwyn Twmffat (author)theturn2014-12-02

Thanks for your excellent comment! These machines have now, quite literally, made many millions of litres of biodiesel which get sent to an independent lab on regular occasions for testing against EN14214. I can assure you that all the reaction and mixing times are correct. The most critical timing is actually the glycerol separation time after the first reaction, not the mixing of the reactants. THIS HAS TO BE NO LESS THAN 60 MINUTES. I'm sure the 10 minutes primary stage mix could be reduced to 5 minutes, but what's 5 minutes in the scheme of things? The tanks are never pressurised as they are all vented to the outside and, although methanol boils at 64 degrees, by the time the pumping stage is finished most of the methanol is locked into the newly formed biodiesel molecules and the rest is dissolved so the boiling point rises to about 70 degrees. There is a technical name for this - boiling point elevation and Raoult's law.

http://en.wikipedia.org/wiki/Boiling-point_elevation

Making biodiesel is a fascinating process and we argue about it for hours/days/weeks/months/years/decades at:

http://www.vegetableoildiesel.co.uk/mybbforum/

Please feel free to join us!

author
rimar2000 (author)2014-12-01

Excelente instructable, felicitaciones.

author
Tecwyn Twmffat (author)rimar20002014-12-02

Muchas gracias . Es el producto de unos diez años de trabajo.

author
Tecwyn Twmffat (author)2014-11-27

More comments can be found here: http://www.vegetableoildiesel.co.uk/mybbforum/showthread.php?tid=38239

author
redsunmtm (author)Tecwyn Twmffat2014-12-01

(SP) Se pueden encontrar mas informaciones aqui:

(FR) pour plus d'infos, voir ce lien:

: http://www.vegetableoildiesel.co.uk/mybbforum/sho...

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