Using Vegetable oil as a diesel fuel

Biodiesel Production Health and Safety

MOST COMMON ACCIDENT: Biodiesel processor blows up due to immersion heater being accidently turned on when empty. REMEDY: Do not build/buy a processor with an immersion heater installed in it. Always heat the vegetable oil in a separate vessel that never has methanol in it.

Biodiesel manufacture is a potentially dangerous industrial process and should never be done in the home.

 Biodiesel production commonly uses some potential lethal chemicals including methanol, caustic soda and concentrated sulphuric acid. Methanol exposure on a small daily dose causes cumulative damage to the body, possibly leading to blindness and death. It is also explosive, similar to petrol, and when mixed with caustic soda it is poisonous, explosive and caustic.

Sodium hydroxide is extremely corrosive. It can cause burning to unprotected skin and is particularly damaging to the eyes. Stirring the liquid can often produce a fine mist of liquid droplets. If this mist is inhaled, severe irritation of the respiratory tract and breathlessness can occur. Accidental swallowing can cause major damage to the throat lining and digestive system.

Methanol is a toxic chemical. It can enter the body through breathing in the vapor, direct skin contact or by accidental swallowing. It can cause nausea, dizziness and visual disturbances that can result in blindness. Swallowing small quantities could pose a significant health threat to the central nervous system and could also affect other vital organs. It is a cumulative poison and repeated exposure to relatively low concentrations could cause harm in the longer term.

 Many people in the biodiesel industry have a very casual attitude to health and safety and prefer to ignore many of the obvious risks with businesses regularly exposing their employees to methanol vapor and home brewer's blowing up their equipment. This is partly due to enviromentalists trying to promote biodiesel as a safe process to benefit the environment, but more often, people trying to make bigger profits in the biodiesel industry by selling processors as 'safe to use'. We have been criticised for discouraging people from producing biodiesel, but surely it is better to be aware of the dangers if a biodiesel producer is to do it safely? Our attitude is different from people like Richard Price of Filtertechnik who is quoted by the Telegraph as saying: "It's not rocket science. The process is pretty simple and perfectly safe", which we think is an irresponsible and misleading thing to say. There are also biodiesel processors on the market promoted as being 'family friendly' consumer items - these should definitely be avoided.

 Accidents in the biodiesel industry have included: methanol spillage igniting and fire spreading to storage tanks, people being burnt by sulphuric acid due to poor training/supervision/suitability, small processors exploding due to accidentally switching on electric immersion heaters, pipework bursting due to using incompatible materials, adding methanol to hot oil and small fires escalating to large fires due to using plastic reactor vessels.

 Designers/users of biodiesel processors may want to take heed of the following advice:

  • Dont use plastic for the biodiesel reactor as it is not suitable for the temperatures required and at these temperatures the fittings come loose as the plastic goes soft resulting in leaks. Leaking methanol can easily catch fire, especially if there is a source of ignition such as an everyday unapproved pump. A small fire underneath or inside a plastic reactor will escalate into a large fire when the plastic starts to burn or melt.
  • Use electrical and mechanical equipment that conforms to the EU regulations for areas that may contain methanol vapour (methanol vapour is explosive at just 5% concentration with air).
  • Do not use cheap single tank systems as these are likely to be dangerous. The reactor should have no electrical parts in it or close to it unless they are certified safe with methanol fumes, which normally makes them extremely expensive.
  • Make sure your processor has a well designed control panel that has fail safe systems in place to prevent immersion heaters from accidentally being turned on or not being able to turn them off.
  • Dont install electrical heating elements in the biodiesel reactor even if there is a float switch etc as the level sensors can get clogged and fail. Use a separate vessel for heating the vegetable oil.
  • Dont advise people to add methanol to the hot oil. Always add methanol to oil and stir whilst doing so. More info.
  • Never add water to acid or methanol to caustic soda.
  • Always have very good ventilation in your workspace.
  • Never make biodiesel in the house or in a garage adjoining, or part of, a home.
  • Never use plastic piping for the transport of any fluid containing methanol downstream of any pump.
  • Always mix or react methanol in closed, externally vented containers. Never use open topped drums or kegs. Never use a food mixer or similar.
  • Never breathe in methanol fumes, even if at low concentrations. Each exposure to methanol will permanantly destroy parts of your nervous system.
  • Dont leave caustic soda lying around on the floor as it smells of salt and animals will try to eat it.
  • Get proper training on how to handle chemicals such as sulphuric acid.
  • Biodiesel should only be made by mature, coherent, sensible and able 'competent people', not children, the elderly, the physically or mentally impaired (apologies where due), or those prone to accidents. You may think this funny, but I once saw the results of a conc sulphuric acid accident due to the fore-mentioned.
  • Dont make biodiesel whilst tired, emotionally upset, or under the influence of alcohol or drugs.
  • Keep your work area tidy and well organised. Put sawdust on oil spillages and sweep up after absorbtion.
  • Do everything practical to ensure safe biodiesel processing and never skimp on health and safety to save time, effort or money.

Recommended biodiesel processor: Twyn Tub 150 MK2



Oops - Kaboom!!!

Methanol vapours explode