Using Vegetable oil as a diesel fuel

Biodiesel viability

Biodiesel Health and safety

Biofuels Training



How to buy a small scale biodiesel processor

The Oil Files DVD

The Twyn Tub 100

Veggi-boost combustion enhancer



Twyn Tub 150 Biodiesel Processor

Twyn Tub 150

  Probably the world's first intrinsically safe, all in one, homebrew biodiesel plant. The design features a hand operated mixer and main pump, reducing the chance of explosion due to electrical spark. Full, professional 3D expanded drawing are available with explanations of the design logic learnt from 7 years of experience on larger industrial applications. Will soon be available with 'Methalyzer' technology which detects methanol vapour and shuts off all the electrics in the control panel. Comes with operating instructions on how to make the highest quality biodiesel from waste cooking oil/ rapeseed oil etc.

Price for the recently upgraded plans for the Twyn Tub 150 MK2: £115.00, including the New full length training and fabrication DVDs (2 separate professionally produced, menu driven DVDs) and postage to mainland UK.

Availability: NOW. £115.00:

Postage options:

Includes free upgrades DVD (PAL format) of step by step assembly and free telephone or email consultancy (you phone us). Use of the plans is subject to terms and conditions. Basically, one machine per plans purchase. The build requires somebody with good welding and plumbing skills. Time to build this machine = 5 days, start to finish. The plans include a fully comprehensive parts list, recommending the cheapest places to buy from, so that the build cost is kept to a minimum, a schematic diagram so that you can understand what you are building and many useful 3D representations and real life photos to give extra clarity. In total, there are 22 double sided A4 pages of information, including 12 colour photographs.

Please note: If you use the plans to build your own Twyn Tub biodiesel processor, YOU buy the parts, straight from the supplier - no middle man or commissions.

Twyn Tub 100 plans


  The 'Twyn Tub' design addresses some serious safety considerations that should be made when making biodiesel. From our extensive research, we have found that the most common accidents are usually a combination of bad design and user error. The main consideration has been to separate the electirc heating elements from the reactor vessel so that there is NEVER an opportunity to turn them on in an empty vessel containing methanol fumes. Many accidents have happened due to having electrical elements in the processor and some are documented HERE.

  Why is this machine safe and not others? Answer: The machine has been professionally designed to minimise the chances of methanol vapour detonation by either spark or very hot metal surfaces. Furthermore, it has been laid out to be very simple to operate, so that the chances of user error are minimised. For example, our reactor (the right hand 'Tub') features a hand operated mixer which avoids the necessity of using a very expensive ATEX rated pump or motor. However, NOT suitable for industrial/work environments.



  • Ultra-safe design.
  • The reactor and heating tanks are made from steel, which has high resistance to pressure and does not go soft at 60 degrees C.
  • The pipe work is mostly made of steel and is properly supported.
  • The main pump is a spark less, high flow rate pump operated by hand to keep the overall machine cost down. The pump is self priming, tolerant of large particles in the oil and resistant to all the chemicals used.
  • The unit is securely mounted on a sturdy platform and cannot be accidentally knocked over in normal operation.
  • There are NO add ons required for this machine, it is all inclusive and ready to go to make high grade biodiesel conforming to EN14214. The machine will accommodate all the stages of the biodiesel process from heating the oil to drying and de-waxing the finished product.
  • The processes used are all well established, employing traditional biodiesel technology with no 'research' techniques or otherwise. It is a fully developed biodiesel processor.
  • The heating tank is fitted with an internal 3KW 240 volt a/c stainless steel/incalloy heating element with thermostat and over temperature safety cutout switch. There is no heating element in the reactor.
  • Low level sensosr prevents immersion heater being switched on accidentally.
  • Secondary thermostatic cutout in case the main thermostat fails.
  • Will NOT turn your biodiesel acidic with 'Dry wash' or ionic exchange wash.
  • The processor is capable of making one batch of biodiesel every 24 hours although we recommend longer settling times to achieve highest quality.
  • Yield is normally 95% and a minimum of 150 litres.
  • Sight tubes to see fluid levels in the tanks.
  • Sample points on both tanks to determine state of reaction/state of drying etc.
  • Waste vegetable oil pre-filter.
  • Spray nozzle filter system.
  • Biodiesel de-waxing system.
  • Conical tank bottoms to get maximum separation efficiency.
  • Electric circulation pump for drying the oil and drying and de-waxing the biodiesel.
  • Plinthe mounted.
  • Full, comprehensive, training available plus full, two day, training course on DVD.
  • Free on site installation with delivery.
  • Spare parts always in stock.

What this machine will do:

  • Filter waste vegetable oil
  • Heat the vegetable oil
  • Separate water from the oil
  • Safely react the methanol with vegetable oil
  • Separate glycerol from the biodiesel
  • Wash and dry the biodiesel
  • De-wax the biodiesel
  • Pump out high quality biodiesel through a filtration unit


Costs to build or buy a Twyn Tub 150 (UK), April 2011:

  • Plans £115
  • Parts and materials £910. Not including control panel (£114).

Our price for complete machine: CLICK HERE

Deposit of £500 secures order and delivery slot (non-refundable). Pay deposit:

Additional deposits will be required for international orders.

Dimensions of machine: 2.2 long x 0.8 wide x 2.0 high (m)
Chemicals required: Methanol, sodium hydroxide, sulphuric acid. All readily available throughout the UK.
Actual man hours per batch: 4 to 5 hours

Cost analysis: (updated on 17th Jan 2009)

  • Personal fuel production allowance before tax is payable (UK)= 2,500 litres.
  • Methanol cost = 35p per litre = 7 pence per litre of biodiesel produced.
  • Electricity cost per litre = 1 pence
  • Water cost = 0.25 pence per litre of biodiesel produced.
  • Catalyst and acid cost = 0.75 pence per litre of biodiesel produced.
  • Waste vegetable oil = FREE if collected personally.
  • Total cost per litre of fuel = 7 + 1 + 0.25 + 0.75 = 9 pence

If the full 2,500 litre quota is used and the price of diesel at the pump was £1.00 a litre and the price of the machine was £2150, the machine would pay for itself in: 12 x 2150 / (2,500 x (1.00 - 0.09)) = 11 months and 10 days.

Videos to watch:
Introduction to the old Twyn Tub 100 biodiesel processor - a video tour of the design features.
New Making biodiesel with the Twyn Tub 150 MK2 biodiesel processor, Day 1  

This video goes through whole Goat Industries 2 day training option that comes with the Twyn Tub 150 MK 2. Normally, customers opt for the training at their own premises so that the machine gets delivered, installed and fully commissioned at the same time by one of our highly experienced technicians.

 You can also buy this 2 day training session on one DVD, lasting 2 hours 30 minutes, for £9.95. Please see below for details.

Purchase a DVD (PAL format) of the training videos: £9.95, UK only. Availability: 4th April 2009
New Making biodiesel with the Twyn Tub 150 MK2 biodiesel processor, Day 2  

Day 2 of the training session.

Need a proper high resolution, professional, menu driven version? Please see the above to buy the DVD of this training.

The Twyn Tub 150 goes to the Isle of Bute, Scotland

 Short news reel showing one of our customers receiving the Twyn Tub and having it commissioned.
3D model
This is the Twyn tub 100 - now superceded by the 150 MK2, but still interesting to watch.
Discuss the Twyn Tub biodiesel processor on:
This product has been independently reviewed on:

Customer's testimonials on the Twyn Tub 150 MK2:

Extras and options:

  • Air operated main pump, add £500.
  • Electric main pump, add £700.
  • Stainless steel tanks, add £600 (machine life span = 25 years with stainless steel).
  • One day's on site training, add £200 (Goes through the basic process but not washing and drying)
  • Two day's on site training, add £300 (Goes through the whole biodiesel process)
  • TT200 now available - same as the 150 except larger tank, produces 200 litres of biodiesel per batch.

Please note that you will need the following chemicals for the training: 35 litres of methanol, 2 kg of sodium hydroxide and 200 litres of liquid vegetable oil.


What to watch out for when buying/building a small scale biodiesel processor:

1. Are you planning to employ people to operate your biodiesel processor? If so, your processor MUST conform with health and safety regulations. These are called ATEX and DSEAR.

2. What materials is the machine made from? Stainless steel is the ideal material for the vessels but this will make the machine expensive. Steel is OK and is 100% resistant to the caustic catalyst used. Plastic is NOT acceptable as it starts to become unstable at 60 degrees, which is very near the biodiesel reaction temperature, and is gradually destroyed by the catalyst dissolved in methanol. Most plastics, except for PTFE (which contains fluorine), will firstly go opaque, then go brittle and then go a dark brown colour with final disintegration within about 2 years. HDPE and PVC are NOT compatible. The pipe work particularly should NOT have braided flexible plastic on the biodiesel mixer pump. This is something to watch out for as it is a sure indicator that the builders of the machine are incompetent. Accidents have been recorded due to accidental pressure build up in flexible pipe work causing an 'annul ism' and subsequent bursting, spraying hot vegetable, oil possibly containing sodium methoxide, over the operator.

3. What pumps are used? The pump for mixing the biodiesel reactants should be spark proof and this normally requires full ATEX zone 1 certification, not only on the electrics, but also the pump itself. Good quality hand operated pumps are OK. Watch out that the pump will handle particles in the fluid as when making biodiesel it is not normal to filter the veg oil beyond about 2mm. Mag drive pumps are NOT tolerant to particle contamination. Centrifugal is the best option. Most machines have an inadequate mixing pump - many are illegal.

4. Where is the pump mounted and is it self priming? If the pump is not mounted below the level of the bottom of the tank it will need to be a self priming pump. Do not buy machines with pumps mounted half way up the vessel and equipped with priming kits - waste of time!

5. Does the machine have internal heating or is it a separate 'add on'? The heater should be ATEX rated to zone 0 if it is in the biodiesel reactor and the reactor itself should have automatic fluid level sensors to prevent the following: Many biodiesel processors use immersion heaters located in the reactor and many accidents have been caused by inadvertently turning/leaving the heater element on in an empty reactor that contains methanol fumes. The result is explosions.

6. Does the machine do all the stages of biodiesel production? These are: Heating, separating any water, drying the waste oil (if used), methoxide mixing, biodiesel reaction, neutralisation of the crude biodiesel, water washing, biodiesel drying and filtration. If any of these stages are missing the biodiesel produced WILL damage your engine.

7. Methoxide mixing: NEVER buy a machine that pumps methanol through a container with the catalyst as this produces a dangerous exothermic reaction. Methanol is generally mixed with a conventional vortex mixer, not a pump. If, for some reason a pump is used for mixing the methoxide, make sure it is a proper ATEX centrifugal pump rated for grinding particles. NEVER mix methoxide in a open topped vessel as the fumes will harm your health.

8. Buy from a reputable supplier. Things to watch out for here are if they say you can make money out of a small scale biodiesel plant. This is NOT true. Due to various economies in scale, it has been calculated that the minimum size to make a profitable business is 5,000 litres per day. Otherwise, it is always going to be a hobby activity. Do NOT buy from people kindly offering to build you a one off machine. Although their intentions may be good, they are unlikely to have the experience to build a safe machine and will therefore be acting illegally. If you do buy an illegal machine, YOU are not acting illegally unless you ask your mate to come and help you. You are allowed to harm yourself but not your mate. Don't buy an illegal machine.

9. Watch out for false claims made by the seller. One is the profitability as above. Another common sales bluff is to exaggerate the production capability of the machine. The way it is done is to say that biodiesel can be produced in 2 hours, giving 12 batches per 24 hour day. This is completely misleading as quality, clean biodiesel cannot be made in less than 24 hours per batch and even this is optimistic. The production from a machine with a reactor capacity of, say 200 litres, is not normally more than 100 litres per day. Be very suspicious of claims more optimistic than this.

10. Look for useful features such as sample points in the reactor and methanol mixing tanks. You need these to test that the process is going to work before mixing the reactants together. Temperature gauges are always useful for peace of mind.

11. Is the unit skid mounted? This is essential if tanks are connected with rigid pipe work as just connecting them on a concrete floor wont be accurate enough to ensure that the joints meet up and don't get strained. If the tanks are not skid mounted they will need to be connected by flexible pipe or by custom onsite built rigid pipe work which are both expensive options and the latter may mean that the machine cannot be moved.

12. Accidents have happened due to bad biodiesel making process. Don't buy a machine that advocates mixing the methoxide into the hot oil, always do it the other way round. Even if the vessel has a temperature gauge, the oil is generally much hotter at the top than at the bottom. If the oil is over 65 degrees C at the top and you add methanol or methoxide the methanol will boil off, potentially causing a pressure build up and subsequent bursting of the vessel, especially if it is plastic. Then, if you've got non-spark proof motors running and a large methanol spillage you've got the perfect recipe for a major explosion.

13. Biodiesel production IS dangerous. Don't buy equipment from suppliers who claim that it is safe. The chemicals used are deadly poisonous and highly explosive. Companies marketing biodiesel production as a safe family activity are acting in a very irresponsible manner and risk heavy fines and imprisonment if an accident occurs. If the suppliers claim that biodiesel production is safe, then their equipment is likely to be unsafe and probably wont work properly.

14. Be aware of the need for extra add on tanks etc as many machines are not complete biodiesel processors and only do the basic reaction. Ask about pre-processing waste oil, drying the finished biodiesel, de-waxing the biodiesel and final filtration. If the answers are vague - don't buy it!

15. Does the fuel produced meet the European standard (EN14214)? Most biodiesel processor manufacturers have never even tested their fuel by a professional, independant, laboratory. We have made extensive tests on our fuel and can confirm that it will pass EN14214, using the proper recipe. Fuel produced to less than this spec. will be inferior quality and may, for example, still contain over 20% unreacted vegetable oil or even be acidic.

16. Does the process use 'Dry washing', ion exchange, resin, purolite, amberlite or any of the afore-mentioned? If it does - watch out! Ion exchange WILL turn your biodiesel acidic so making it more corrosive and more prone to attacking the parts of the vehicle injection system and anything else made of steel or brass. PLUS, you've still got a disposal issue when you come to replace the beads. PLUS, your fuel will NOT pass EN14214, EVER! Dry washing turns the soaps formed during the biodiesel process back to 'Free Fatty Acids' or 'FFA's. These acids will then react with the parts of the engine's ignition system, corroding the metallic parts and reforming back to thick, sludgy soaps. Soaps should be washed out of crude biodiesel with water and the soapy water disposed of down a sewer drain and not a rain water drain.

17. Does the supplier offer methanol recovery options? Methanol recovery is ESSENTIAL for commercial, large scale plant as to get EN14214 standard biodiesel you will have to use excess methanol, which MUST be recovered again if the plant is to be financially viable. No methanol recovery = either no EN14214 or high methanol expense or 3 day glycerol separation time lag to meet EN14214. Methanol recovery is not necessary for biodiesel units under 250 litres per batch.

18. Does the supplier offer comprehensive training? You cant learn how to make biodiesel in one hour, training should be at least one day long and should cover all the health and safety aspects in full detail. Most accidents occur due to user error and a good training course helps prevent this. The best training courses will be backed by written instructions and even video DVDs.