The New B100-WH Biodiesel Reactor (with Dry Wash)


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Welcome to the updated B100-WH biodiesel reactor page . B100-WH is the designation given to this version of the water heater based reactor / processor for the home based production of biodiesel from a waste vegetable / used cooking oil ( WVO/UCO ) feedstock. All links to this page are welcomed and a partial text paragraph may be used freely only in the event that it precedes to this page. Please do not hotlink images.

The 3 stages of making biodiesel

The 3 stages of making biodiesel

Getting started :

The first thing that needs to be done,after being assured that the oil does not contain water, is to find out what the levels of FFA’s (Free Fatty Acids) are in the oil. This is done by the process of titration. A reliable method of titration is a priority for the most commonly used method of producing homebased Biodiesel. The school of thought on methods varies slightly from author to author, however it must show the accurate titration level in order for the proper amount of catalyst, be it Sodium Hydroxide/NaOH, or Potassium Hydroxide/KOH that is to be disolved into the Methanol/Methyl Hydrate forming a layman’s methoxide.

  • These substances are classified as a Dangerous Goods (HazMat) and so appropriate safety measures must be applied when handling and using them *.

And the result of using a proper amount of this mixture will achieve a complete reaction and result in Faty Acid Methyl Esters (Biodiesel).

Here is a method describing titration;

  • The method we use consists of 40 ml of 99% isopropyl alcohol and 4 ml WVO/UCO blended together in a jar sitting in a warm water bath until disolution is achieved. Then we slowly add drops of 1% sodium hydroxide solution (1gr NaOH in 1 liter distilled water) until a PH of 8.5 is reached on the electronic PH meter. The number of ml’s of 1% NaOH solution used, divided by 4, will be added to the base amount of NaOH (between 5 and 5.5gr) to give a total grams per liter of WVO/UCO catalyst amount to be disolved in the methanol creating the needed methoxide solution for the reaction.

We use 20% methanol per liter WVO/UCO, so for an 80 liter batch of oil we will use 16 liters methanol to which is added the base catalyst amount plus the titration results to form the needed amount of methoxide.

The Isopropyl alcohol we use is 99% pure and was acquired at a pharmacy on special order. Store it in a cool dark dry place, and only pour enough for short term use into a seperate bottle using the larger one as a fill up bottle.

It cannot be stressed enough how important the titration is in the production of good homebased biodiesel. Use the best possible equipment you can find / afford. This is not the area to skimp on quality. Here we use a tripple-beam scale and electronic PH meters that are calibrated before each use. The scale is a My Weigh Tripple Beam Balance. And there are two electronic PH meters that we use; the first is an American Marine Pinpoint Ph Meter and the second is a Hanna Instruments Checker Pocket PH meter -pH-2 WP. The places that sell these meters (supply houses or aquarium shops) can also provide buffer solutions needed to calibrate them. There are other methods of recording the PH level, such phenolphthalein, phenol red and turmeric (the spice) however the electronic PH meter is the one we use.


Most experienced homebased producers of Biodiesel ( Faty Acid Methyl Esters ) will recommend that test batches be done prior to engaging a larger one. This is a scaled down volume of a larger batch that is anticipated later. Here we do 500ml oil with 100ml methanol (20%) and NaOH (Sodium Hydroxide) according to a base amount of 5gr/Lt + titration results. Heat the oil to 55C (130F) with the pre-measured and disolved methoxide waiting in the wings in a flip top Grolsch beer bottle, which works very well for this purpose and is completely fumeless (no fumes escape into the air). It’s good beer too 🙂 A properly made batch will have the esters separate from the glycerine content by a clear line distinguishing the two.

Preparing to Process :

What you need to get things going is a supply of waste vegetable /used cooking oil. The titration was done using a sample of prospective oil to see if it was suitable, not containing water or too high an FFA level, for the process to be done without substantial extra effort and/or chemicals. Many places are happy to give you their oil free and will even help you in your quest to a more environmentally friendly fuel by pre-filtering and putting the used oil in cubies or containers that you supply. And that brings us to:

Test batch w / clear glycerine separation

Test batch w / clear glycerine separation

Collecting and filtering the UCO:

There are several ways to collect your UCO, all depending on just how intricate you want to be about it. Some use vaccum tanks and pumps, electric pumps, hand pumps and then there are those who simply go in there with a 1 gal jug cut out to act as a scoop and bring some 22 liter pails along. One item that can save time and effort is a filtering screen such as one of these in the 200 micron rating : Ez-Strainer.
Water can present a problem in getting used oil from a unknown source, so a test is necessary to determine if there is water present or not BEFORE you titrate it. This can be done by heating a sample of the oil to 100C (212F) to boil off the water but be careful to stir regularly if the crackling shows that there is water present or it can cause a steam bubble and you end up with hot oil all over the place when it vulcanoes. You should know before then if there is water by the crackling noises the oil will make along with a rolling motion.
One method of removing the water if you do get some is to heat the oil to about 40-45C for about 30 minutes and then let cool. The water will settle to the bottom and then you can syphon off the top 90% for biodiesel use. This method does not work if there is cleaning solution in the oil.

You do not have to filter the WVO/UCO prior to processing to a meticulous extent, just the main food particles is plenty. The rest will come out in the glycerine layer during the processing. Finer filtration is only recommended for those wishing to make soap from the raw by-product afterward (it makes for a nicer soap).

Getting the Methoxide Ready :

OK, so now we have sampled, titrated and collected the oil. Now we have to prepare the methoxide. Methoxide is made mixing of the NaOH or KOH with methanol / methyl alcohol. We use 20% methanol in which we disolve the amount of catalyst the titration gave us plus the standard base amounts. The NaOH will disolve slower than the KOH will. The best method is to keep it completely fumeless as these are two dangerous chemicals and need to be handled with care. Pour the needed amount of methanol first into an HDPE 2 rated (little triangle on the bottom with a “2” in it and the letters HDPE over or below it) natural colour 20 liter (5gal) carboy / jug equipped with a vent cap and 70mm cap center-threaded to accept 3/4″ plumbing, and then slowly add the caustic (NaOH or KOH) and close it up, then slosh it around by rocking it back and forth to get the dissolultion started. You can either leave it overnight and it will eventually dislove on it’s own or just rock the carboy back and forth occasionally until it has completely disolved. It is important that it is completely disolved which is why you use a natural coloured carboy so you can see through it and determine if the catalyst has disolved or needs more time or gentle agitation.

We have equiped our 20 liter carboy with a Delrin Sleeve stiffener in the vent cap. This is a small tubular brass piece that is flared slightly at one end and snugly holds a conventional air hose without the need for clamps. The idea is to first tighten down the vent cap and then mark the cap and carboy body with a line and then drill through both simultaneously, but the hole should be just barely big enough to let the stiffener sleeve go through but not the flared end. Then open the vent cap and from it’s inside push the stiffener sleeve through so that the flared end comes up against the inside top of the vent cap and then tighten it all down remembering to line up the marks you made on the cap and carboy body. This ensures that the holes are lined up.


This will be air assisted by an aquarium air pump via the vent cap’s Delrin Sleeve opening in case the check valve refuses to open completely to allow proper methoxide flow. The air adds pressure inside the carboy and forces the methoxide to flow easier, also avoiding the potential for vaccum buildup inside the carboy as you are replacing the volume of methoxide inside the carboy with air from the air pump. Flow is controled by the air and also by the ball valve at the bottom of the delivery tube. This also contributes to the “fumeless” operation of the process, by keeping the vent hole closed to the outside air.

Now your methoxide is ready and set up.

Now your methoxide is ready and set up.

Loading the Reactor:

The B100-WH uses a pre-heat tank to warm up the WVO/UCO to it’s operating temperature of 55C (130F). The heater is a 115V screw in type water heater element that is used for the conversion of square shaped heaters to the round screw in type.


The square flange is welded into the side of the tank and then the round element is screwed into it. We produce 80 liter batches at a time, even though the B100-WH is capable of larger batches, as that is the volume that is simplest to process, using only one 20 liter carboy of methoxide instead of needing a second with less methoxide just to process an extra 20 liters. The pre-heat tank holds 40 liters so it must be filled twice and emptied into the main reactor using a Northern Tool 1″ Clear Water Pumpplumbed down to 3/4″ NPT to match the overall 3/4″ NPT threads throughout the reactor’s plumbing.

The 1″ Clear Water Pump is NOT self priming. To overcome this we have set the preheat tank above the level of the feed tube’s inlet (valve BP-4) to the pump and that way the liquid follows the path of least resistance and primes the pump as it attempts to go up the sight tube to reach the level of the preheat tank’s outlet. Otherwise it must be manually primed before use. The reactor is a Giant water heater of the “fatboy” type with dimensions essentially the same as the 200 liter drum used for settling.The total capacity is 135 liters (30 Imp gal), however that is not the volume of biodiesel that will be made. Space must be allowed for the oil, the methoxide and some head space for circulation. This is why we have settled on 80 liter batches with the B100-WH reactor.

Operating the B100-WH Biodiesel Reactor:


The first thing we must do is load the reactor. Open the inlet port at the top of the reactor (up-V-3) and an air intake (up-V-1).We use a preheat tank who’s outlet port is set above the inlet port of the 1″ clear water pump. This provides self priming for the pump, which normally is not self priming. Once the WVO/UCO has been heated to reaction temperatures (55c / 130F) it must be transfered to the reactor. This is accomplished by firstly opening an air vent on top of the reactor (up-V-1), and closing the tank’s main drain valve (BP-1). Open the feed valve (BP- 4) as well as the valve on the preheat tank and wait for the oil to show up in the sight tube after having primed the pump. The heat from the preheat tank should now be off . Flip on the reactor’s pump on and empty the preheat tank. Repeat this a second time to fill it to 80 liters capacity and then close BP- 4 and the valve on the preheat tank. Open the tank’s main drain outlet (BP-1) and the second isolation valve (BP-3) , be sure BP- 2 is closed so the hot oil doesn’t go out the glycerine drain, and circulate the oil checking that the temperature registering on the thermometer is right. If it is not at processing temperature (55C / 130F) flip on the reactor’s heating element. After a few minutes of recirculating check the thermometer again. The thermometer is mounted at the top of the sight tube as it T’s into the reactor. Keep the oil circulating with the air vent on top (up-V-1) still open. Now it is time to introduce the methoxide.


While the hot oil is circulating with the reactor’s heat off and the air vent open *slowly* start introducing the methoxide by opening the ball valve at the carboy’s outlet and opening the methoxide delivery valve (BP- 5). After flipping on the air pump there should be a noticable change in colour of the circulating oil in the sight tube. The air pump charges the carboy with light air pressure and forces the check valve open. It should take several minutes (10-20 minutes) to fully empty the methoxide into the oil flow if it is done right. Once the methoxide has been completely introduced into the oil fow it is time to shut the air pump, methoxide delivery valve (BP- 5) as well as the one on the carboy. Also close the air vent at the top of the reactor (up-V-1) and circulate the mixture for about two to two and one half hours. The mixing process is now complete.

The reacted product must now be allowed to settle for about 8 hours so that the glycerine by-product will drop out of the oil and the biodiesel will sit atop it. As a side benefit to this design, once the processing is done we still have the sight tube, pump and lines full of reacted biodiesel still containing the glycerine that has not yet seperated. Should this be allowed to stay in the pump, lines ect. there is a possibility that it harden there causing future problems. To eliminate this open the air vent at the top of the reactor (up-V-1) and open the glycerine drain (BP- 2). Have something ready to receive the draining product.

With air coming in from the top,and the glycerine drain (BP-2) open the reactor, sight tube, lines, pump ect. flush out the residual reacted biodiesel.

The only other valve we have not discussed is BP- 3 . This is an isolation valve to stop any glycerine from reaching back to the pump should the option be used to keep the settling inside the reactor and not send it to a seperate tank. When BP- 3 is closed and BP- 1 opened the draining has nowhere to go, so we open BP- 2 (glycerine valve) and drain out the glycerine first. Before opening anything though there must be an air vent opened on top of the reactor (up-V-1) otherwise it causes gulping air via the open lower valve to make up for volume leaving the tank and that will mix the glycerine with the biodiesel. The only time all valves are all completely closed is during the actual circulation/mixing time, otherwise the outside vent is always open.

Another option, and the one we use and prefer, is to immediately send the completed reaction to a seperate settling tank that has been equipped with the StandPipe design where two bungs are used at the bottom and one has an 8″ elevated pipe inside. This design allows for the biodiesel to be drained first, and then the glycerine to be drained afterward. This helps ensure that glycerine and biodiesel stay seperated so as not to cause problems later. Once the reaction is complete,and while the mix is still circulating, draw a sample of about 500ml’s into a jar via the glycerine drain valve (BP-2) to check on the biodiesel/glycerine seperation.

Now open the vent (up-V-1) . The next valve to open is (up-V-4). This is the one that comes from the settling tank and goes out of doors thus venting air allowing the biodiesel to be transfered but also it vents potentially dangerous methanol fumes from the hot oil mixture entering the settling tank from the reactor. Now open (up-V-2) while closing (up-V-3). Remember we have not stopped circulating the oil and now we have simply redirected the flow from going back into the reactor and into the settling tank instead.

Once most of the biodiesel has been transfered and no more will pump, close the pump, up-v-2 (the transfer hose) as well as up-V-4, the settling tank vent. The hot biodiesel mixture is now isolated in the settling tank. But we still have reacted biodiesel in the pump and lines and also some left over in the reactor, so, as above, we must drain these to avoid further problems. First we open (up-v-1) allowing air to be sucked in from the outside. Then open (up-V-3) to permit this air to follow down the sight tube and into the pump. Have a pail or bucket ready under the glycerine drain (BP-2) and then open it. The reacted biodiesel in the lines, pump and reactor will drain out this port. You are now ready to start another batch in the reactor while the first ones starts to settle.

Water heaters as a reactor :

The water heater has become a very popular way of setting up a biodiesel reactor. The reason for this is simple. They are completely closed to the air (fumeless), and easily obtainable either new or used from plumbing enterprises who replace old ones. They come in a variety of sizes that adapt easily to differing peoples’ needs. They have outlets in all the right places.

Preparing a water heater is fairly simple also; remove all existing drains and tubes, including the anode rod (magnesium rod sometimes found in a seperate port under the insulation) and dip tube and replace them with 3/4″ NPT black iron plumbing. Black iron because galvanised iron and copper react negatively with biodiesel. For simplicity’s sake in N.America most people chose to convert them from their 240V to 115V configuration, although this is not mandatory, but using 240V elements in a 115V source will greatly reduce it’s output. Those outside N.America who use 220V as standard voltage need not change the heating element. Most have a top and bottom element; in all cases the top one must be disabled so that only the bottom one is usable. For the water heaters having a square flange type element it is sometimes necessary to get a conversion flange and screw in type element to replace it with. These can usually be had where the water heaters are sold.

There exists a major flaw in the design use of a water heater as a biodiesel reactor however. After the processing of the oil / methoxide mixture the mix must be settled. This gives a layer of glycerine by-product on the bottom and a layer of biodiesel on top. The problem with water heaters is that they may not drain cleanly. In other words, they leave some residual glycerine by-product on the bottom and when the glycerine by-product is drained (BP_ 2) out after it’s settling time not all of it comes out, even if a few liters of biodiesel are allowed to drain along with it. This is because the water heater’s outlet port is slightly raised creating a lip inside to trap the glycerine. Coned-bottom tanks have a greater potential for draining cleanly or near clean enough so that the glycerine does not cause problems in the next phase, washing.

There are two predominant methods used today for homebased biodiesel producers to wash their fuel; one is the water wash and the other is the dry wash. Water washing involves suplemental tanks that will be used for washing and drying the biodiesel, whereas dry washing traditionally uses an ion exchange resin in purification tanks to finish processing the biodiesel into useable fuel and no water or drying is necessary. Another option in dry washing is The GL Eco-System.

Final filtering is recommended for both methods. Below we offer examples of both water and dry washing :


The Benz, and it’s cousin (another Benz) and their diet of B100 homebased biodiesel are a very happy combination.

In our opinion, the installation of a second, heated fuel tank in the vehicle solves all geling problems associated with cold weather use of biodiesel. Problem that varies with the type of oil used as feedstock as some are more tolerant of the cold than others, however a little heat overcomes this geling problem. This type of system is widely used with those using SVO (Straight Vegetable Oil) as an alternative to diesel fuel, although in their application a great deal more heat is required to adequately reduce the oil’s viscosity (thickness), a thing that has already been adressed in the transesterification (making biodiesel) process.

Biodiesel is much more tolerant of heat exposure ( flash point over 149C / 300F) than it’s counterpart, petroleum diesel, so running it in a warm tank is not going to harm it or your engine. Installing ball valves at the T’s to the engine coolant by-pass gives you the flexibility to turn the heat on or off to the “hot” tank at will. Summer temperatures do not require heat for B100 biodiesel. In our opinion those using SVO in their vehicles should consider a tank full of B100 (100% biodiesel) every 4th or 5th tank fills profiting from biodiesel’s solvent properties to keep fuel lines, pumps ect clean and clear.

If you would like to visit our own heated winter B100 use system please click here . Thank you for your interest.


The Life of Rudolph Diesel

The history of Diesel and his engine can be read at this link :

  • Historical Perspectives